environmental technology systems awareness learning tool enter

Environmental Technology Systems Awareness

Learning Tool

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Environmental Technology Systems Awareness

Welcome

Welcome to the ‘Environmental Technology Systems Awareness’ learning tool which is one of four learning tools that have been developed by the Skills for Climate Change project.

How to use this tool

The main way to navigate around this tool, use the forward and back arrows in the bottom right corner of each screen.

In some areas of the tool a set of icons similar to those below will appear for you to select from.

You can click on the icon from anywhere in the tool to access the module menu page.

Introduction

Welcome to the ‘Environmental Technology Systems Awareness’ learning tool.

The purpose of the tool is to enable you to develop a fundamental knowledge of micro-renewable energy and water conversation technologies .

The aim of the learning tool is to :

• develop your understanding of the fundamental working principles of micro-renewable energy and water conservation technologies

• enable you to recognise the top level regulatory requirements that apply in relation to micro-renewable energy and water conservation technologies installation

• enable you to recognise the fundamental requirements of building location/building features for the potential to install micro-renewable energy and water conservation systems to exist.

• enable you recognise the typical advantages and disadvantages of micro-renewable energy and water conservation systems

Please note: This learning tool is not intended to develop the occupation competence to design or install micro-renewable energy and water conversation technologies. The information and illustration provided is limited to awareness only. The diagrams provided only contain the relevant technical detail for awareness purposes and must not be used as installation diagrams.

When is it appropriate to install environmental technology systems?

Before we move onto the rest of the tool, it is important to understand the role that environmental technology systems have in helping to address climate change and improve sustainability. Before considering the installation of environmental technology systems it is essential that approaches to reduce demand and to improve efficiency are taken first .

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Learning Tool Overview

This learning tool includes four modules:

To enable you to gain a good overall awareness and understanding, It is recommended that you study all four modules; however, the modules can be studied in any order.

Each module includes points. It is recommended that you complete each learning check before you move on.

To begin, click on any module above.

Module 1: Heat Producing Technologies


Solar Thermal Hot Water Systems

Objectives

At the end of this section you will:

• understand the fundamental working principles of solar thermal hot water systems• recognise the top level regulatory requirements that apply in relation to solar

thermal hot water systems installation work• recognise the fundamental requirements of building location and building features

for the potential to install to a solar thermal hot water system to exist• recognise the typical advantages and disadvantages of solar thermal hot water

systems


Solar Thermal Hot Water Systems – Basic System Categories

Although there are a number of system types, variations and configurations, solar thermal hot water systems fall into two basic system categories:

• passive systems• active Systems

In passive systems, the system circulation takes place by the natural thermosiphon or convection process. For this process to work the solar collector needs to be mounted below the storage cylinder. As this arrangement is not as practical in the UK as it is in warmer countries, the majority of systems installed in the UK are ‘active’ systems where the system circulation takes place due to the inclusion of a circulating pump.


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Click on each number for a brief overview of the purpose of the system component

Solar Thermal Hot Water Systems - Indirect Active System (with Twin-Coil Cylinder)

Please note that due to the intended purpose of this learning tool, some system components are not shown. This is not an installation diagram.


Solar Thermal Hot Water Systems – Direct Active Systems

In direct solar hot water systems, the domestic hot water that is stored in the cylinder is directly circulated through the solar collector.

This type of system can be added to existing hot water systems, but it is essential that all system components are compatible with the system design. For example, as the domestic hot water is circulated through the solar collector it is not possible to add anti-freeze protection to the system water – therefore some components such as the solar collector need to be freeze tolerant.



Solar Thermal Hot Water System Components - Solar Collector

Sometimes referred to as a solar panel, the collector is mounted in a suitable location (usually on a roof). The collector absorbs the sun's energy and uses it to heat the heat transfer fluid within the system.

Types of Solar Collector

‘Flat Plate’ Solar Collectors

‘Evacuated Tube’ Solar Collectors


Solar Thermal Hot Water System Components - Differential Temperature Controller

The Differential Temperature Controller (DTC) is the heart and brains of the system. Linked to high level and low level temperature sensors the DTC only allows the system circulating pump to operate when there is:

1. solar energy available2. there is a demand for water to be heated


Solar Thermal Hot Water System Components - Circulating Pump

The circulating pump circulates the system heat transfer fluid which is either water or glycol depending upon the type of system, around the solar hot water circuit.

The operation of the circulating pump is controlled by the Differential Temperature Controller

Where a space heating system is installed, the boiler typically provides the auxillary heat source for the solar hot water system. Where there is no space heating the auxillary heat source is typically an electric immersion heater


Solar Thermal Hot Water System Components – Auxillary Heat Source

In the UK, solar thermal hot water systems require an auxillary heat source to heat the stored domestic hot water when there is either:

1. insufficient solar energy to heat the water fully; or 2. no solar energy to heat the water


Solar Thermal Hot Water System Components – Storage Cylinder

The storage cylinder stores the domestic hot water and allows for the heat transfer from the solar collector circuit to the stored domestic hot water. A popular cylinder type is the twin coil cylinder. This type of cylinder incorporates a lower solar heating coil and a higher auxillary heating coil. Some cylinders will also include a shunt pump to circulate the stored water in the cylinder when just the auxillary heat coil is in operation

One of a number of alternative arrangements is to use a separate solar pre-heat cylinder as shown below. This arrangement is less common.



How did you do?

Question Answer

Most solar hot water systems in the UK fall into which system type category?

Active or pumped systems

What types of solar collector are available? Flat plate and evacuated tube

What is the function of the Differential Temperature Controller?

To control the system circulating pump to operate only when there is:1. solar energy available2. there is a demand for water to be heated

What is the purpose of an auxillary heat source?

To provide back-up heat when there is no or insufficient solar energy available to heat the water

Click here to reveal





Solar Thermal Hot Water Systems – Regulatory Requirements

The installation of a solar thermal hot water system will require compliance with a number of regulatory requirements including health and safety, water regulations, electrical regulations. A competent installation contractor will have a detailed knowledge of these regulations and will ensure compliance.

Within this section we consider two primary regulatory requirements in relation to solar hot water systems:

• Building Regulations• Town and Country Planning Regulations

Note: The requirements stated in this section relate to England and Wales only. The requirements for Scotland and Northern Ireland may differ.



The Building Regulations (England and Wales) comprise of 14 parts. Seven of these parts may have relevance to solar hot water systems installation.

Part Topic Relevance or possible relevance

A Structure Where solar collectors and other components put load on the structure, in particular wind uplift loads.

B Fire Safety Where holes for pipes etc. may reduce the fire resistant integrity of the building structure

C Site preparation and resistance to moisture Where holes for pipes etc. may reduce the moisture resistant integrity of the building structure

E Resistance to the passage of sound Where holes for pipes etc. may reduce sound proof integrity of the building structure

G Sanitation, hot water safety and water efficiency

Hot water safety and water efficiency

L Conservation of fuel and power Energy efficiency of the system and the building

P Electrical safety in dwellings Safe installation of electrical controls and components










Town and Country Planning Regulations – Building Mounted Collectors

The installation of a solar hot water system collector array is typically classed as permitted development for houses and bungalows providing :

• the solar collectors are not installed above the ridgeline and do not project more than 200mm from the roof or wall surface.

• the solar collectors are sited, so far as is practicable, to minimise the effect on the appearance of the building

• the solar collectors are sited, so far as is practicable, to minimise the effect on the amenity of the area.

• the property is not a listed building*• the property is not in a conservation area or in a World Heritage Site

The Local Planning Authority should be consulted for clarification, particularly for installations to flats and non-dwelling building types.

*Listed Building Consent may be required even if planning permission is not required.



Town and Country Planning Regulations – Stand-alone Collector Arrays

The installation of a stand-alone solar hot water system collector arrays is typically classed as permitted development providing :

• The array is no higher than four metres• The array is sited at least 5m from boundaries• The size of array is limited to 9m2 or 3m wide and 3m deep• The array is not being installed within boundary of a listed building• In the case of land in a conservation area or in a World Heritage Site the array will not be

visible from the highway.• Only one stand-alone solar installation is being installed.



Solar Thermal Hot Water Systems - Building location and feature requirements

For the potential to install to a solar thermal hot water system to exist, as a minimum some or all of the following building and location factors will need to be considered:

• orientation of the solar collectors• tilt of the solar collectors• adjacent structures or obstructions that introduce overshading• the availability of a suitable solar collector mounting structure• compatibility with any existing hot water system


Solar Thermal Hot Water Systems – building location and feature requirementsCollector Orientation

In the UK, we tend to relate a south facing garden in our homes to the availability of the most sunshine throughout the day. Well the same applies in relation to solar hot water systems.

The ideal orientation is south facing. Orientations between south east and south west will also provide good results.

For buildings with suitable east and west facing roof areas, a split collector system is possible with solar collectors mounted on both east and west facing roof slopes.


Solar Thermal Hot Water Systems – building location and feature requirementsSolar Collector Tilt

As well as orientation, the ‘tilt’ of the solar collector is also key factor that determines the amount of solar energy that is transferred from the sun to the solar hot water system.

Collector ‘tilt’ is the angle that the solar collector is mounted from the horizontal plane.

Where a pitched roof already exists, the tilt is typically determined by the roof pitch.

Where there is no pitched roof available, it is possible to mount solar collectors on vertical and horizontal surfaces. Solar collectors may also be mounted on purpose built support frames to provide the required tilt. However, this type of installation typically requires more design consideration and consultation with product manufacturers etc.


Solar Thermal Hot Water Systems – building location and feature requirements

What is the optimum orientation and tilt given in the table above? Click on the forward arrow to check your answer

Tilt of Collector

Orientation of collector

South SE/SW E/W NE/NW North

Horizontal 961

300 1073 1027 913 785 730

450 1054 997 854 686 640

600 989 927 776 597 500

Vertical 746 705 582 440 371Annual solar radiation kWh/m2 (Source: Table H2, SAP, 2009)

We have identified that the building orientation and collector tilt are key factors in determining the amount of available solar energy that is transferred from the sun to the solar hot water system. Now let’s examine some data….


Solar Thermal Hot Water Systems – building location and feature requirements

Tilt of Collector

Orientation of collector

South SE/SW E/W NE/NW North

Horizontal 961

300 1073 1027 913 785 730

450 1054 997 854 686 640

600 989 927 776 597 500

Vertical 746 705 582 440 371

Annual solar radiation kWh/m2 (Source: Table H2, SAP, 2009) The optimum orientation and tilt given in the table above is south facing at a 30o tilt.

Typically, a collector tilt of between 30o and 40o from horizontal is considered to be very close to optimum with 35o being optimum.


Solar Thermal Hot Water Systems – building location and feature requirementsOvershading

Any overshading of the solar collector(s) will have an impact on how much available solar energy that is transferred from the sun to the solar hot water system

Overshading % of sky blocked by obstacles

Impact of overshading

(% reduction in potential system

performance)

Heavy ˃ 80% 50%

Significant ˃ 60 - 80% 35%

Modest 20% - 60% 20%

None or very little

˂ 20% none

Based upon Table H4, SAP, 2009


Solar Thermal Hot Water Systems – building location and feature requirementsSuitable Collector Mounting StructureThe collector mounting structure must be suitable in terms of being:

• of sufficient size (m2)− typically a minimum of 3- 4m2 of suitable collector mounting

area is needed with approximately 0.75m2 to 1m2 of collector area being required per person

• strong enough to support the collectors− as well as considering the the potential for collapse or

damage to the structure under normal conditions, wind uplift loads must be considered and assessed.

• in good condition − there is no sense in installing a solar collector to a roof that

is in a poor state of repair. Any repairs or refurbishment should be carried out prior to installing the solar collector(s)

Point of use systems and instantaneous centralised systems are not normally suitable for use with solar hot water systems. However, some combination boilers are compatible with solar pre-heated water. Product manufacturer’s instructions should always be consulted for advice.


Solar Thermal Hot Water Systems – building location and feature requirementsCompatibility with any Existing Hot Water System

Existing hot water systems come in various types and configurations. Three types of systems are shown below:



How did you do?

Question Answer

What type of solar hot water system is typically suitable for a property with and East/West roof orientation?

A split collector system with solar collectors mounted on both east and west facing roof slopes

What effect will heavy overshading of solar collectors have on system performance?

A potential reduction in system performance of approximately 50%

What are the essential requirements for a structure to be suitable for the mounting solar collectors?

1. Sufficient size2. Strong enough3. In good condition

Which type of hot water system is most compatible with a solar hot water system?

A centalised storage system






Solar Thermal Hot Water Systems – Advantages and Disadvantages

Some example advantages and disadvantages are:

Advantages Disadvantages

Reduces carbon dioxide emissions Not compatible will all existing hot water systems

Solar energy is free, energy costs will be reduced

Less solar energy is available in the winter months

Relatively low maintenance is needed Initial installation costs can be off-putting

Improves Energy Performance Certificate ratings

Needs a linked auxillary heat source

Well Done! You have now completed the solar hot water systems section.

Click on the forward arrow to return to heat producing technology system menu page


Heat Pump Systems

Objectives


• understand the fundamental working principles of a heat pump unit• know the common types of heat pump unit• know the types of heat emitters that are suitable for heat pump system installations• recognise the top level regulatory requirements that apply in relation to heat pump

systems installation work• recognise the fundamental requirements of building location and building features

for the potential to install heat pump systems to exist• recognise the typical advantages and disadvantages of heat pump systems


Heat Pump Systems

What is a heat pump?

A heat pump is a device for converting low temperature heat a to higher temperature heat

Some heat pumps can also work in reverse and convert high temperature heat to a lower temperature

So how does a heat pump work? ………………


Heat Pump Systems

How does a heat pump work?

Most heat pumps make use of the mechanical vapour compression cycle commonly known as the refrigeration cycle to convert heat form one temperature to another. The heat pump refrigeration cycle works on a similar principle to a domestic refrigerator but in reverse.

Let’s look at how the heat pump refrigeration cycle works ………………


Heat Pump Systems

Heat pump refrigeration cycle

1. The low temperature heat (heat source) enters the Evaporator which is a heat exchanger . A refrigerant on the other side of the evaporator is at a cooler temperature than the heat source and heat is transferred from the source into the refrigerant causing the refrigerant to evaporate. 2. The now gaseous refrigerant enters the compressor, resulting in a rise in the temperature and pressure of the refrigerant.

3. The refrigerant continues its course through the Condenser (which is also a heat exchanger) transferring the higher temperature heat to either an air or water distribution circuit (often referred to as the ‘heat sink’ or emitter circuit). 4. The refrigerant, now at a cooler temperature, enters the expansion valve, which reduces its pressure and temperature to its initial state at the evaporator. The cycle then repeats itself.


Heat Pump Systems

How efficient are heat pumps?

Heat pumps are classified as a ‘low’ carbon technology because they need some electrical energy to operate.

Depending on the application, operating conditions and type of heat pump utilised, heat pump energy output can be 300% to 500% more than the electrical energy input.

Heat Pump efficiency is referred to as Coefficient of Performance (COP) In its simplest form COP relates to heating output divided by the electrical power input. For this example the COP is 4.0, calculated as follows:

Heating output (4kW) ÷ Electrical power input (1kW) = 4.0


Heat Pump Systems

Heat pump technology can convert low temperature heat from an air, ground or water source to higher temperature heat for use in ducted air or piped water ‘heat sink’ systems. The type of heat pump unit must be selected in relation to the intended ‘heat source’ and ‘heat sink’ arrangement’

Let’s now look at the options in more detail………….


External Air Source Heat Pump System Options

A variety of heat pump system arrangements are possible using the external air as the heat source. Air source heat pump will typically operate at temperatures up to -20 oC. Air source heat pumps can be single internal units that receive the incoming air through an inlet duct that passes through the external wall of the building . An popular alternative is the use of an external fan coil (evaporator) unit that is linked to an internal unit. Fan coil units can be noisy and this need to be considered at the design stage.

Let’s now look at the ground source options ………….


Ground Source Heat Pump System Options

A variety of heat pump system arrangements are possible using geothermal ground heat as the heat source. A variety of closed (sealed circuit) collector loop arrangements can be used. SlinkyTM type collectors (illustrated) are sometimes used where available ground area (m2) is limited.

External ground source heat pump units (not illustrated) are also available.

Let’s now look at some more ground source options ………….



An alternative to horizontal ground collector loops is a vertical collector loop installed in a borehole.

This type of installation requires a specialist drilling rig to be used to create the borehole. A specialist contractor is normally used to undertake the drilling operation.

Vertical borehole collector loops are often used where the geothermal conditions support the use of a ground source heat pump but where the available ground area (m2) is limited.

Click on next for more ground source options ………….



An ‘open’ vertical borehole ground collector loop is an alternative to a ‘closed’ vertical borehole ground collector loop.

With this arrangement , two boreholes are used and the collector circuit is open and the collector circuit fluid flows naturally from the open ended return pipe to the open ended flow pipe. . This type of arrangement requires the availability of a suitable geothermal water source.

Click of next for water source collector circuit options ………….


Water Source Heat Pump System Options

Where a suitable water source exists such as a lake or a pond, this can be a very effective alternative to a ground source collector circuit. For illustration purposes the SlinkyTM type collector is shown in a vertical position, but water source collectors are simply laid on the bottom of the lake or a pond and weighted as necessary to keep them in place. ‘Open’ water source collector circuits (not illustrated) are also an option.


Heat Pump Systems

How did you do?

Let’s now look at the ‘heat sink’ emitter circuit options ………….

Question Answer

What type of heat conversion process does a heat pump use?

A refrigeration circuit

What types of heat source options exist? Air, ground and water

What types of heat sink circuit exist? Air and piped water

What is the typical % increase in energy output from a heat pump in relation to the electrical energy input?

300% to 500%

What does Coefficient of Performance relate to? Heat pump efficiency (heating output divided by the electrical power input)







One of the factors that affects heat pump system efficiency is the temperature difference between the heat source and the heat sink. The closer the temperature between the heat source and the heat sink circuit, the better the Coefficient of Performance.

Traditional ‘wet’ heating systems that incorporate a condensing boiler use a mean (average) water temperature of approximately 70oC. A heat pump system mean water temperature will typically be between 30oC and 40oC

The lower mean water temperature dictates that some types of heat emitter and hot water storage cylinder are more suitable than others for use with heat pump systems.

Heat Pump System Piped Water ‘Heat Sink’ (Emitter) Circuits


Heat Pump System Piped Water ‘Heat Sink’ (Emitter) Circuit Options

Heat pumps using a piped Water ‘Heat Sink’ Circuit can be used to heat domestic hot water storage vessels (1), underfloor heating circuits (2), radiators (3) and fan convector heaters (4). However, some of these are more suitable than others. Click on each number for more information and when finished click on next

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Domestic Hot Water Storage

Heat pumps can be used to heat a domestic hot water storage cylinder. Standard type indirect hot water storage cylinders are not suitable for heat pump system due to the size of the heat transfer coil. A ‘tank-in-tank’ hot water cylinder is the most appropriate for use with heat pumps. Some heat pump units have an integrated ‘tank-in-tank’ cylinder.

The ‘tank-in-tank’ design provides a large surface to surface contact between the heating circuit water and the stored domestic hot water. This design is very suitable due to the lower temperature of the heating circuit water in a heat pump system when compared to a traditional boiler-fed heating system.

A ‘boost’ or auxillary heater is required to boost the stored water temperature to standard 60oC domestic hot water storage temperature


‘Tank-in-Tank’ Hot Water Cylinder


Underfloor Heating

Underfloor heating systems operate at a lower mean (average) water temperature than a heating system with radiators.

Therefore, underfloor heating is very suitable for use with heat pumps.



Panel Radiators

Standard type panel radiators are designed to work at a mean (average) water temperature of approximately 70oC. A heat pump system mean water temperature will typically be between 30oC and 40oC


To be effectively and efficiently used with a heat pump system, standard type panel radiators would need to be significantly over-sized to enable the required heat output to be achieved using a lower mean water temperature . This factor means that heat pump units are typically less suitable for use with existing standard type panel radiator circuits that have been sized for a mean water temperature of 70oC.

Low temperature, high efficiency panel radiators are available and these are more suitable for use in a heat pump heat sink circuit. Where low temperature, high efficiency panel radiators are used, the Coefficient of Performance will typically be lower than if underfloor heating is used.


Convector Heaters

Natural and fanned convector heaters are suitable for use with heat pumps.

As is the case with low temperature, high efficiency panel radiators, where natural and/or fanned convector heaters used, the Coefficient of Performance will typically be lower than if underfloor heating is used.


Fanned Convector Heater


Buffer Tanks

Some heat sink circuits make use of a component called a buffer tank. In basic terms, a buffer tank is a vessel that accumulates and stores heating circuit water ready for use when needed.

Heat Pump System Piped Water ‘Heat Sink’ (Emitter) Circuits

Heat pumps are not designed or sized to meet short-term heat loads. For efficient operation a heat pump heeds to be able to start-up and run for a period of time. Stop-start operation can also shorten the life of the heat pump compressor.

Buffer tanks are also useful where an auxillary heat source such as a boiler is being used with a heat pump. This type of system is known as a bivalent system.

Most air source heat pumps, particularly those with an external fan coil unit need to defrost regularly. Buffer tanks are also useful to provide heat for the defrost cycle.


Heat Pump Systems – Regulatory Requirements

The installation of heat pump systems will require compliance with a number of regulatory requirements including health and safety, water regulations, electrical regulations. A competent installation contractor will have a detailed knowledge of these regulations and will ensure compliance.

Within this section we consider two primary regulatory requirements in relation to heat pump systems:





The Building Regulations (England and Wales) comprise of 14 parts. Seven of these parts may have relevance to heat pump systems installation.


A Structure Where heat pumps and other components put load on the structure


C Site preparation and resistance to moisture Where holes for pipes etc. may reduce the moisture resistant integrity of the building structure

E Resistance to the passage of sound Where holes for pipes etc. may reduce sound proof integrity of the building structure














Town and Country Planning Regulations

Installing a ground source or water source heat pump system does not usually need planning permission and should fall within permitted development rights.

Due to potential noise issues, most air source heat pump installation currently require planning permission. However, this is currently being reviewed and as soon as relevant standards and safeguards to deal with noise have been established air source heat pumps are likely to be classified as permitted development.

The Local Planning Authority should be consulted for clarification, particularly for installations in conservation areas and installations to non-dwelling building types.



Heat Pump Systems - Building location and feature requirements

For the potential to install to a heat pump system to exist, as a minimum some or all of the following building and location factors will need to be considered:

• an appropriate heat source (air, ground or water)

• the availability of a suitable location to mount the components - particularly the potential for noise issues if an air source heat pump is being considered

• The compatibility of the proposed installation with any existing heating and hot water system unless a new heating and hot water system is to be installed


Heat Pump Systems

How did you do?

Question Answer

What is the mean water temperature used in a heating system connected to a heat pump ?

30oC to 40oC

What type of domestic hot water cylinder is most suitable for use in a heat pump system?

A ‘tank-in-tank cylinder

What component can be used to prevent the heat pump cycling on and off during short-term heat demand periods?

A buffer tank

Which type of heat pump installation is most likely to require planning permission?

Air source






Heat Pump Systems – Advantages and Disadvantages



Reduces carbon dioxide emissions Not usually suitable for connection to existing heating systems using panel radiators

Efficiencies between 300% to 500% are typical. Initial installation costs can be off-putting

Relatively low maintenance is needed Air source installations can present a noise issue


Ground source installations require a large ground area or a borehole

Well Done! You have now completed the heat pump systems section.



Biomass Fuelled Systems

Objectives


• understand the fundamental working principles of biomass fuelled systems• recognise the top level regulatory requirements that apply in relation to biomass

fuelled systems installation work• recognise the fundamental requirements of building location and building features

for the potential to install to a biomass fuelled system to exist• recognise the typical advantages and disadvantages of biomass fuelled systems



The Biomass Resource

Biomass fuelled systems are generally considered to be carbon neutral. This is because the carbon dioxide released when combustion takes place is equal to the carbon dioxide that was used during tree growing process.

Even when the carbon dioxide produced through the growing, harvesting and transportation processes is taken into account, biomass fuelled systems are extremely carbon friendly when compared to fossil fuelled appliances

Logs Logs have been used to provide heating for hundreds of years and is the original biomass fuel. Logs for biomass appliances need to be of maximum length and diameter

Wood Chip Wood Chip is typically produced from the ‘small round-wood’ that is left over when trees are felled and logs are harvested but can also be produced from reclaimed timber

Pellets Wood pellets are pellets made from fine wood particles such as sawdust. They are cylindrical in shape, typically 6 or 8mm wide (diameter), and 15-30mm long.



Within this section we look woody biomass fuels i.e fuels that come from a wood source

Woody Biomass fuels come in three main types:

Note: woody biomass fuels must be stored in a dry environment to minimise the fuel moisture content level. Logs and wood chip also require a ventilated storage area



Biomass Appliances

In this section we look at two main categories of biomass appliance:

• Biomass stove• Biomass boiler

Each type of appliance has a range of fuel type and output options

Biomass Stove Biomass Boiler



Biomass stove fuel options

Some biomass stoves burn pellets and some burn logs.

Pellet burning stoves include a integrated hopper and an auger feed mechanism that transfers the pellets from the hopper to the burner when heat is needed. Log burning stoves require manual loading.

The typical heat capacity range for biomass stoves is 5- 15kW but some stoves can be regulated to outputs as low as 2kW



Biomass stoves output options



Biomass boiler fuel options

Biomass boilers are available for all three main type of biomass fuel. Some biomass boilers are multi-fuel boilers.

Pellet burning boilers and wood chip boilers will include some type of automated feed arrangement to transfer the fuel to the burner. In many cases and automated feed arrangement is also used to transfer the fuel from the store to the appliance. Log burning boilers require manual loading.

Most biomass boilers also include an automated arrangement to clean the heat exchanger surfaces



Biomass boiler output options

Biomass boilers can provide heat for domestic hot water and space heating purposes.

The typical minimum heat output rating for biomass boilers is 8kW for pellet boilers, 12kw for log boilers and 25kW for wood chip boilers. Biomass boilers are typically more suited to larger domestic properties, non-domestic applications and communal heating schemes.

For smaller domestic properties, a biomass stove that can provide heat for domestic hot water and space heating purposes is often used.


Biomass Fuel Storage and TransferFor smaller installations, biomass pellets are available in sealed bags that can be carried and loaded directly into the appliance.

For larger installations with automated fuel transfer, the fuels can either be stored in the existing building in a room near the boiler, or in a separate store outside the building.

External storage options include an underground store or over ground silo from where the fuel is fed to the boiler by auger or suction. In underground stores for pellets, it is important to ensure that no moisture can get in. Stores for chips should be well ventilated to let the wood dry and prevent mould.

The size of the fuel store depends on many factors: anticipated fuel requirements, fuel type, reliability of deliveries, space available, delivery vehicle capacity etc.

It is normally cheaper to have large loads of fuel delivered providing suitable storage is available.


Biomass Fuelled Systems - some example pellet storage and automated suction feed arrangements


Question Answer

Why is biomass considered to a carbon neutral fuel ?

Because the carbon emitted during combustion is used in the growing process for new biomass fuels.

As well as logs and pellets, what other type of biomass fuel is available?

Wood Chip

What type of biomass appliance is typically the best type for a small property?

A stove

What type of biomass fuel is suitable for storage in a circular underground storage tank?

Pellets







Biomass Fuelled Systems – Regulatory Requirements

The installation of a biomass fuelled system will require compliance with a number of regulatory requirements including health and safety, electrical regulations and regulations relating to smoke control. A competent installation contractor will have a detailed knowledge of these regulations and will ensure compliance.

Within this section we consider three primary regulatory requirements in relation to biomass fuelled systems

• Building Regulations• Town and Country Planning Regulations• The Clean Air Act and Smoke Control Zones




A Structure Where the biomass appliance and other components put load on the structure


C Site preparation and resistance to moisture

Where holes for pipes etc. may reduce the moisture resistant integrity of the building structure

E Resistance to the passage of sound

Where holes for pipes etc. may reduce sound proof integrity of the building structure



J Combustion appliances and Fuel Storage system

Biomass appliances are a heat-producing combustion appliances and must be installed safely












The Building Regulations (England and Wales) comprise of 14 parts. Eight of these parts may have relevance to biomass systems installation.


Biomass Fuelled Systems – Regulatory RequirementsTown and Country Planning Regulations

Planning permission is not normally needed when installing a biomass fuelled system in a house if the work is all internal. If the installation requires a flue outside, however, it will normally be permitted development if the conditions outlined below are met:

• Flues on the rear or side elevation of the building project to a maximum of one metre above the highest part of the roof.

If the building is listed or in a designated area even if the building has permitted development rights it is advisable to check with the local planning authority before a flue is fitted. Consent is also likely to be needed for internal alterations.

In a conservation area or in a World Heritage site the flue should not be fitted on the principal or side elevation if it would be visible from a highway.

If the project also requires an outside building to store fuel or related equipment the same rules apply to that building as for other extensions and garden outbuildings.



The Clean Air Act and Smoke Control Areas

Under the Clean Air Act, local authorities may declare the whole or part of the district of the authority to be a smoke control area. It is an offence to emit smoke from a chimney of a building, from a furnace or from any fixed boiler if located in a designated smoke control area. It is also an offence to acquire an "unauthorised fuel" for use within a smoke control area unless it is used in an "exempt" appliance.

The Secretary of State for Environment, Food and Rural Affairs has powers under the Act to authorise smokeless fuels or exempt appliances for use in smoke control areas in England.

Where a biomass appliance is to be installed to a property located within a smoke control area, the appliance must be an exempted appliance. The Department for Environment, Food and Rural Affairs (DEFRA) provides information regarding smoke control areas, exempted appliances and exempted fuels. The information is available at http://smokecontrol.defra.gov.uk/


Biomass Fuelled Systems - Building location and feature requirements

For the potential to install to a biomass fuelled system to exist, as a minimum some or all of the following building and location factors will need to be considered:

• A suitable flue or chimney system or the potential to install a suitable flue or chimney system. The flue system must be constructed of, or lined with a material that is a suitable to receive the products of combustion from a biomass appliance. Prefabricated gas appliance flue systems are not suitable for biomass appliances. The flue must also be fitted with and appropriate terminal to disperse the products of combustion.

• A suitable location and arrangement for fuel storage. Factors such a space, moisture, access for fuel deliveries and the frequency of fuel deliveries must be considered.



How did you do?

Question Answer

Is the installation of a biomass stove in a house classified as permitted development under the Town and Country Planning Regulations?

Yes providing:Flues on the rear or side elevation of the house project no more than one metre above the highest part of the roof.The house is not listed, not in a designated area not in a conservation area or in a World Heritage site

What is an ‘exempted appliance’? An appliance that is permitted for use in a Smoke Control Area

What does DEFRA stand for? The Department for Environment, Food and Rural Affairs





Biomass Fuelled Systems – Advantages and Disadvantages



Biomass is a carbon neutral technology Requires a suitable flue/chimney system

Does not rely on building orientation or weather conditions to operate effectively

Initial installation costs can be off-putting

Biomass is generally considered to be an inexhaustible fuel source

Typically require a large space to store fuel

The cost of producing biomass for use as fuels and energy sources is very cheap compared to the cost of finding and extracting fossil fuels

Sometimes considered less suitable for smaller properties

Well Done! You have now completed the biomass fuelled systems section.


Module 2: Electricity Producing Technologies


Solar Photovoltaic Systems

Objectives


• understand the fundamental working principles of solar photovoltaic systems• recognise the top level regulatory requirements that apply in relation to solar

photovoltaic systems installation work• recognise the fundamental requirements of building location and building features

for the potential to install to a solar photovoltaic system to exist• recognise the typical advantages and disadvantages of solar photovoltaic systems


Solar Photovoltaic Systems – Introduction

In basic terms a solar photovoltaic system is a system that uses solar cells to convert light energy from the sun into electricity.

Solar cells are semiconductors -typically silicon. A group of solar cells is known as a solar photovoltaic module

Photons in sunlight hit the solar cells and are absorbed by the cell. This process causes the negatively charged electrons within the solar cell to come loose from their atoms allowing them to flow through the cell to produce electricity. The electricity that is produced is direct current (d.c.) – the type of electricity that is produced by a battery.

Solar photovoltaic is a zero carbon technology. solar photovoltaic module


Solar Photovoltaic Systems – Basic System Categories

Although there are a number of system types, variations and configurations, solar photovoltaic systems fall into two basic system categories:

• ‘on-grid’ systems• ‘off-grid systems

‘On-grid’ systems allow any surplus electricity that is generated to be exported to the electricity distribution grid. This type of system is very popular since the introduction of the Feed-in Tariff scheme

‘Off-grid’ systems use a battery bank arrangement to store the electrical power generated for use when needed.

‘on-grid’

‘off-grid’

Some system installations will combine ‘on and ‘off’ grid arrangements


Solar Photovoltaic Systems – Direct Current and Alternating Current

Some electrical appliances operate using direct current electricity, but the most common type of electricity used in our homes and places of work etc. is alternating current.

Before direct current (d.c) electricity that is generated by a solar photovoltaic system can be used with alternating current (a.c.) systems and appliances, the electricity has to be converted from d.c. to a.c. electricity.

It is only possible to export alternating current (a.c.) electricity to the electricity distribution grid. Therefore on-grid a.c. solar photovoltaic systems are the most popular an common type of system.

Let’s now look at the typical layout of an ‘on-grid’ solar photovoltaic system in more detail.


1

2

Click on each number for a brief overview

Solar Photovoltaic Systems - Components (‘on-grid’ systems)


4

3


Solar Photovoltaic System Components - Solar Photovoltaic Module

Sometimes referred to as a solar photovoltaic panel, solar photovoltaic modules are mounted in a suitable location - often on a building - where they will receive the maximum amount of solar light energy.

As previously explained, solar photovoltaic modules contain solar cells that convert light energy from the sun into electricity.

A group of solar modules is known as an solar array.

A range of different solar photovoltaic modules (monocrystaline, polycrystaline, thin-film etc.) are available, each type having different levels of efficiency.

Roof mounted solar photovoltaic modules can be mounted on the surface of the roof using a rail system or integrated into the roof surface. Some manufacturers also make solar photovoltaic roof tiles.


Solar Photovoltaic System Components - Inverter

The inverter is the system component that converts the direct current (d.c.) to alternating current (a.c).

Depending upon the photovoltaic module array layout and size, the d.c voltages that enter the inverter can be very high.

The inverter can be mounted in the roof area adjacent to the PV module location or in the building.


Solar Photovoltaic System Components – Consumer Unit

The consumer unit or fuse board as it is sometimes referred to is used to as the connection point for the solar photovoltaic system installation. .

Where the existing consumer unit is of a modern type, and has a spare connection circuit point available, it can often be utilized. Older type consumer units will need to be replaced at the time that the solar photovoltaic system is installed.


Solar Photovoltaic System Components – Generation Meter

A generation meter is fitted to record how much solar generated electricity has been exported to the supply grid.

Some energy supplier’s incoming supply (import) meter have the capability to perform this function but a generation meter is typically included as part of the solar photovoltaic installation.

The generation meter must be of an approved type and located in a position where it is easily accessible for reading purposes.



How did you do?

Question Answer

Where is a semiconductor material used in a solar photovoltaic system?

In a solar cell

What is the most popular type of solar photovoltaic systems?

‘On-grid’ systems

What is a solar photovoltaic array? A group of two or more solar photovoltaic modules

What is the function of a solar photovoltaic system inverter?

To convert the d.c. electrical electricity generated by the solar photovoltaic array into a.c. electricity






Solar Photovoltaic Systems – Regulatory Requirements

The installation of a solar photovoltaic system will require compliance with a number of regulatory requirements including health and safety, electrical regulations and regulations relating to the connection of ‘on-grid’ solar photovoltaic systems. A competent installation contractor will have a detailed knowledge of these regulations and will ensure compliance.

Within this section we consider two primary regulatory requirements in relation to solar photovoltaic systems:





The Building Regulations (England and Wales) comprise of 14 parts. Five of these parts have relevance to solar photovoltaic systems installation.


A Structure Where solar photovoltaic modules and other components put load on the structure, in particular wind uplift loads

B Fire Safety Where holes for cables etc. may reduce the fire resistant integrity of the building structure


Where holes for cables etc. may reduce the moisture resistant integrity of the building structure


Where holes for cables etc. may reduce sound proof integrity of the building structure

P Electrical safety in dwellings

Safe installation of electrical controls and components








Town and Country Planning Regulations – Building Mounted Arrays

The installation of building mounted solar photovoltaic arrays is typically classed as permitted development providing :

• the solar modules are not installed above the ridgeline and do not project more than 200mm from the roof or wall surface.

• the solar modules are sited, so far as is practicable, to minimise the effect on the appearance of the building

• the solar modules are sited, so far as is practicable, to minimise the effect on the amenity of the area.

• the property is not a listed building*• the property is not in a conservation area or in a World Heritage Site

The Local Planning Authority should be consulted for clarification, particularly for installations to flats and non-dwelling building types.




Town and Country Planning Regulations – Stand-alone Arrays

The installation of a stand-alone solar photovoltaic arrays is typically classed as permitted development providing :

• The array is no higher than four metres• The array is sited at least 5m from boundaries• The size of array is limited to 9m2 or 3m wide and 3m deep• The array is not being installed within boundary of a listed building• In the case of land in a conservation area or in a World Heritage Site the array will not be

visible from the highway.• Only one stand-alone solar installation is being installed.



Solar Photovoltaic Systems - Building location and feature requirements

For the potential to install to a solar photovoltaic system to exist, as a minimum some or all of the following building and location factors will need to be considered:

• orientation of the solar photovoltaic array• tilt solar photovoltaic array• adjacent structures or obstructions that introduce overshading• the availability of a suitable solar photovoltaic array mounting

structure


Solar Photovoltaic Systems – building location and feature requirementsOrientation

In the UK, we tend to relate a south facing garden in our homes to the availability of the most sunshine throughout the day. Well the same applies in relation to solar photovoltaic systems.

The ideal orientation is south facing. Orientations between south east and south west will also provide good results.


Solar Photovoltaic Systems – building location and feature requirementsSolar Photovoltaic Array TiltAs well as orientation, the ‘tilt’ of the solar photovoltaic array is also key factor that determines the amount of solar energy that is harnessed from the sun and converted to electrical energy.

‘Tilt’ is the angle that the solar photovoltaic array is mounted from the horizontal plane.

Where a pitched roof already exists, the tilt is typically determined by the roof pitch.

Where there is no pitched roof available, it is possible to mount solar photovoltaic arrays on vertical and horizontal surfaces. Solar photovoltaic array may also be mounted on purpose built support frames to provide the required tilt.

Typically, a tilt of between 30o and 40o from horizontal is considered to be close to optimum

Orientation

East South West

-90 -75 -60 -45 -30 -15 0 15 30 45 60 75 90

Tilt from horizontal (o)

90 56 60 64 67 69 71 71 71 71 69 65 62 58

80 63 68 72 75 77 79 80 80 79 77 74 69 65

70 69 74 78 82 85 86 87 87 86 84 80 76 70

60 74 79 84 87 90 91 93 93 92 89 86 81 76

50 78 84 88 92 95 96 97 97 96 93 89 85 80

40 82 86 90 95 97 99 100 99 98 96 92 88 84

30 86 89 93 96 98 99 100 100 98 96 94 90 86

20 87 90 93 96 97 98 98 98 97 96 94 91 88

10 89 91 92 94 95 95 96 95 95 94 93 91 90

0 90 90 90 90 90 90 90 90 90 90 90 90 90


Solar Photovoltaic Systems – building location and feature requirementsOptimum Orientation and Tilt

‘Solar sundial showing the likely yield (%) of optimum for different orientation and tilt arrangements


Solar Photovoltaic Systems – building location and feature requirementsOvershading

Any overshading of the solar photovoltaic array will have an impact on much solar energy is harnessed from the sun and converted to electrical energy.

Heavy overshading will reduce the performance of the system by approximately 50% during peak irradiation. Modest overshading will reduce performance by approximately 20%,

Overshading can also lead to thermal stress in solar photovoltaic modules causing malfunctioning to occur, possibly leading to early component failure.


Solar Photovoltaic Systems – building location and feature requirementsSuitable Solar Photovoltaic Array Mounting Structure

The solar photovoltaic array mounting structure must be suitable in terms of being:

• of sufficient size (m2)− The required area will vary according to the module efficiency.

Typically a minimum of 8m2 of suitable array mounting area is needed for each 1000 watts of electricity generation under peak conditions (1 kWp or kilo-watt peak)

• strong enough to support the array− as well as considering the the potential for collapse or damage under

normal conditions, additional factors such as wind uplift loads and snow loading will also need to be considered

• in good condition − there is no sense in installing a solar photovoltaic array to a roof that

is in a poor state of repair. Any repairs or refurbishment should be carried out prior to installing the array



How did you do?

Question Answer

What is the optimum orientation for a solar photovoltaic array in the UK?

South facing

What is the optimum tilt angle for a solar photovoltaic array?

Between 30o and 40o from the horizontal plane

What effect will overshading have on a solar photovoltaic array?

Reduce performance (and possibly lead thermal stress and malfunctioning)

What are the essential requirements for a structure to be suitable for the mounting of a solar photovoltaic array ?

1. Sufficient size2. Strong enough3. In good condition






Solar Photovoltaic Systems – Advantages and Disadvantages



It is a zero carbon technology Requires a relatively large array area to make the installation worthwhile

The technology qualifies for Feed-In Tariff payments


Most buildings are suitable for the technology Variable performance according to the availability of solar energy


Some people consider that solar photovoltaic arrays reduce the appearance of the building

Well Done! You have now completed the solar photovoltaic systems section.

Click on the forward arrow to return to the electricity producing technology system menu page


Micro-Wind Turbine Systems

Objectives


• understand the fundamental working principles of micro-wind turbine systems• recognise the top level regulatory requirements that apply in relation to micro-wind

turbine systems installation work• recognise the fundamental requirements of building location and building features

for the potential to install to a micro-wind system to exist• recognise the typical advantages and disadvantages of micro-wind systems


Micro-Wind Systems – Introduction

Micro-wind systems make use of the natural wind resource to generate electrical energy

A basic wind turbine operates on the principle that wind passing across the rotor blades of a turbine cause a ‘lift’ and ‘drag’ effect which in-turn causes the hub to turn. The hub is connected by a low-speed shaft to a gearbox which increases the speed of rotation of the shaft. The high-speed shaft is connected to a generator that produces electricity.

Basic horizontal axis wind turbine


Micro-Wind Systems – Introduction

The horizontal axis wind turbine (HAWT) that we have just seen is the most common type of turbine.

Vertical axis wind turbines (VAWT) are also available.

Vertical axis wind turbines accept wind from any direction and do not include the tailfin detail that is included on horizontal axis turbines.

This type of turbine also includes a gearbox and generator.

Basic vertical axis wind turbine


Micro-wind Turbine Systems – Basic System Categories

Although there are a number of system types, variations and configurations, micro-wind turbine systems fall into two basic system categories:


‘On-grid’ systems allow any surplus electricity that is generated to be exported to the electricity distribution grid. This type of system is included in the Feed-in Tariff scheme


‘on-grid’

‘off-grid’

Some system installations will combine ‘on and ‘off’ grid arrangements


Micro -Wind Turbine Systems – ‘Wild Current’

Most micro and small scale wind turbines (less than 20 kilowatt (kW)) produce "wild" (variable voltage and frequency) alternating current (AC) electricity which is rectified to direct current (DC) via a system controller. This DC is then either directly used to charge batteries or is converted using an inverter to normal AC (240V 50Hz).

Let’s now look at the typical layout of an ‘on-grid’ micro-wind system in more detail.



Typical ‘on-grid’ micro-wind turbine system


It is also possible to mount micro-wind turbines directly onto the building, although this is not recommended for small buildings or for premises where noise and flicker may be an issue


Micro -Wind Turbine Systems

How did you do?

Question Answer

What are the main types of micro-wind turbine?

Horizontal axis wind turbines (HAWT) and vertical axis wind turbines (VAWT)

What type of wind turbine accepts wind from any direction?

A vertical axis wind turbine (VAWT)

What is a micro-wind turbine system battery pack used for?

To store the electricity that has been generated by the turbine until it is needed

What options are there for mounting a micro-wind turbine ?

Mast mounted or building mounted






Micro-Wind Turbine Systems – Regulatory Requirements

The installation of environmental technology systems will require compliance with a number of regulatory requirements including health and safety, electrical regulations and regulations relating to the connection of ‘on-grid’ micro-wind turbine systems. A competent installation contractor will have a detailed knowledge of these regulations and will ensure compliance.

Within this section we consider two primary regulatory requirements in relation to micro-wind turbine systems :





The Building Regulations (England and Wales) comprise of 14 parts. Five of these parts may have relevance to micro-wind turbine systems installation.


A Structure Where micro-wind turbines are mounted on buildings and put load on the structure




E Resistance to the passage of sound Where holes for cables etc. may reduce sound proof integrity of the building structure










The installation of micro-wind turbines is not classed as permitted development.

At present planning permission is nearly always required to install a micro-wind turbine to a building, or grounds surrounding a building.

Factors that may affect whether permission is granted or not include:

• visual impact• noise• vibration• electrical interference (with TV aerials)• safety

The Government is currently reviewing the planning requirements formicro-wind turbines and it is possible that some permitted development will be included in the future.


Micro-Wind Turbine Systems - Building location and feature requirements

For the potential to install to a micro-wind turbine system to exist, as a minimum some or all of the following building and location factors will need to be considered:

• average wind speed• height at which the turbine can be mounted• obstructions and turbulence• a location that will not be affected by turbine noise, vibration

and flicker


Micro-Wind Turbine Systems - Building location and feature requirementsAverage Wind Speed

The average wind speed is a critical factor in determining the viability of a micro-wind turbine system. Wind speed is measure in metres per second (m/s)

Whilst micro-wind turbines will typically start generating electricity at 3-4 m/s, the minimum viable wind speed is 5 m/s.

Most micro-wind turbines will reach their maximum rated output at between 10-14 m/s so this is the ideal wind speed range.

Wind speed can be measured on-site using an anemometer but if this is done measurements should be taken over a period of months to be accurate.

There is a national wind speed database but this database is no longer being updated. The database also has limitations in terms of its relevance to micro-wind turbine installations.


Micro-Wind Turbine Systems - Building location and feature requirementsHeight, Obstruction and Turbulence Considerations

As wind speed typically increases with height, the basic principle is the higher the mounting location the better.

A high mounting location with a smooth prevailing wind flow is ideal.

To minimise the effect of turbulence, micro-wind turbines should ideally be mounted at a distance equal to 10 times the height of the nearest obstruction


Micro-Wind Turbine Systems - Building location and feature requirementsNoise, Vibration and Flicker Considerations

All wind turbines will generate some degree of noise, vibration and shadow flicker which caused by the sun passing across the turbine rotor blades as it spins.

These factors are much less of a consideration when the micro-wind turbine can be located away from buildings.

Where a micro-wind turbine is to be building mounted, careful consideration must be given to these factors.



How did you do?

Question Answer

Which part of the Building Regulations need to be considered when a micro-wind turbine is to be mounted directly onto a building ?

Part A - Structure

Is a micro-wind turbine installation classified as permitted development?

No – planning permission is normally required

What is the minimum recommended average wind speed for a micro-wind turbine?

5 m/s

What is the ideal average wind speed range for a micro-wind turbine?

10 to 14 m/s






Micro-Wind Turbine Systems – Advantages and Disadvantages



It is a zero carbon technology Requires a suitable mounting site, ideally well away from buildings and obstructions



Micro-wind turbine electricity generation output levels can be very good in the UK which has 40% of Europe’s wind resource

Variable performance according to the availability of wind

Can be a very effective technology where no mains electricity is available

Micro-wind turbines can cause noise, vibration and flicker problems

Well Done! You have now completed the micro-wind turbine systems section.



Micro-Hydropower Systems

Objectives


• understand the fundamental working principles of micro-hydropower systems• recognise the top level regulatory requirements that apply in relation to micro-

hydropower systems installation work• recognise the fundamental requirements of building location and building features

for the potential to install to a micro-hydropower system to exist• recognise the typical advantages and disadvantages micro-hydropower systems


Micro-Hydropower Systems – Introduction

Micro-hydropower systems make use of the natural water resource to generate electrical energy

A micro-hydropower turbine operates on the principle that water passing across or through a turbine causes the turbine to rotate. The turbine shaft is connected to a generator that converts the hydropower to electrical energy

Micro-hydropower is a zero carbon technology.


Micro-Hydropower Systems – Basic System Categories

Although there are a number of system types, variations and configurations, micro-hydropower turbine systems fall into two basic system categories:


‘On-grid’ systems allow any surplus electricity that is generated to be exported to the electricity distribution grid. This type of system is included in the Feed-in Tariff scheme


‘on-grid’

‘off-grid’


Micro–Hydropower System – Basic principles

Water is taken from a high level watercourse or other source via a purpose made inlet.

The water passes through a pipe known as a ‘penstock’ to reach the turbine unit.

As water passes through the turbine the hydropower is harnessed and electricity is generated.

As water leaves the turbine unit it is returned to the watercourse or another discharge to a suitable location via a outlet known as a tailrace.


Micro-Hydropower Systems - Building location and feature requirements

For the potential to install to a micro-hydropower system to exist, the key requirements are:

• the availability of a water course (river, stream etc.)• the ability to achieve adequate ‘hydraulic head’ an ‘flow’ within

the system design• a suitable location for an inlet• a suitable location for the turbine and generator• a suitable location for the tailrace outlet

Adequate ‘hydraulic head’ an ‘flow’ is also a key factor that will determine the type of micro-hydropower turbine that can be used.


Micro–Hydropower Systems – Head and Flow

Head = the vertical distance between the upper and lower water levels or the vertical distance between the intake and turbine

Flow = the quantity of water that is moving over a given period of time


Micro-Hydropower Systems - Turbine Classification

Micro-hydropower turbines are classified according to their ability to operate in high, medium or low head conditions and also are classified being either an ‘impulse’ turbines or a ‘reaction’ turbine according to how they operate:

• Impulse turbine – where the turbine wheel or runner is surrounded by air and the turbine is moved by the impulse created by a jet or ‘jets’ of water that is aimed at the turbine. Types of impulse turbine include Pelton, Multi-jet Pelton, Turgo, Cross-flow.

• Reaction turbine - where the turbine wheel or runner is fully immersed in water and the turbine is moved in reaction to flow of the water Types of reaction turbine include Francis (spiral case), Francis (open-flume), Propeller and Kaplan


Micro–Hydropower Systems – Example Pelton Type ‘Impulse’ Turbine


Micro–Hydropower Systems – Example Horizontal Francis Type ‘Reaction’ Turbine

Plan view Side view


Micro–Hydropower Systems – Example turbine applications in relation to available head of water

Turbine Type Head Classification

High (> 50m)

Medium (10 to 50m)

Low (> 10m)

Impulse PeltonTurgo

Multi-jet Pelton

CrossflowTurgo

Multi-jet Pelton

Crossflow

Reaction Francis (Spiral Case) Francis (open-flume)Propeller

Kaplan


Micro–Hydropower Systems – Example ‘Reverse Archimedian Screw’ Type Turbine

The ‘Reverse Archimedian Screw’ is an alternative type of turbine that is sometimes used for larger micro-hydropower schemes. This type of turbine is particularly suitable for low head installations and is also ‘fish friendly’ allowing fish and eels to pass through without injury.


Micro–Hydropower Systems

How did you do?

Question Answer

What is the purpose of a the ‘penstock ‘in a micro-hydropower system

To carry water from the inlet to the turbine

After the availability of a water course, what is the next key factor that will determine the potential for a micro-hydropower installation?

Suitable hydraulic head and suitable flow

Which type of turbine operates using a jet or ‘jets’ of water ?

An impulse turbine

What type of turbine is most likely to be considered as ‘fish friendly’?

A reverse archimedian screw turbine






Micro-Hydropower Systems – Regulatory Requirements

The installation of a micro-hydropower system will require compliance with a number of regulatory requirements including health and safety, electrical regulations and regulations relating to the connection of ‘on-grid’ micro-hydropower systems. A competent installation contractor will have a detailed knowledge of these regulations and will ensure compliance.

Within this section we consider three primary regulatory requirements in relation to micro-hydropower systems:

• Building Regulations• Town and Country Planning Regulations• Environmental Regulations



Micro-Hydropower Systems– Regulatory RequirementsThe Building Regulations (England and Wales) comprise of 14 parts. Five of these parts may have relevance to micro-hydropower systems installation, depending upon the actual installation details and arrangements. Where a micro-hydropower systems is partly installed in or connected to a habitable building some or all of the following may apply.


A Structure Where any part of the micro-hydropower system puts load on the structure





Where holes for cables etc. may reduce sound proof integrity of the building structure

P Electrical safety in dwellings

Safe installation of electrical controls and components in dwellings







Micro-Hydropower Systems – Regulatory Requirements


As we have identified, the key features of a micro-hydropower scheme include:

• a hydraulic 'head' - vertical distance from water source to the turbine.• a water intake • a pipe or channel to take water to the turbine• a turbine, generator and electrical connection• an outflow, where the water returns to the watercourse

These elements raise a number of important planning issues and planning permission will usually be needed. The elements of a small-scale hydro electricity scheme create potential impacts on:

• landscape and visual amenity • nature conservation • the water regime.

Some form of environmental assessment is also essential when it comes to applying for planning permission and environmental licenses.


Micro-Hydropower Systems– Regulatory Requirements

Environmental Regulations – Licences

All water courses of any size in England and Wales are controlled by the Environment Agency. To remove water from them (even though it may go back in) will almost certainly require their permission in the form of a licence. There are three licences that can apply to a hydropower scheme:

• Abstraction Licence - if water is being diverted ‘away from the main line of flow of the river’. Part of the consideration will be fish migration. Most micro-hydropower turbines are not ‘fish friendly’ so where fish migration is a factor, an abstraction licence will only be issued with conditions stating the requirement for fish screens and a fish pass arrangement

• Impoundment Licence - if changes are being made to structures which impound water, such as weirs and sluices, or if new structures are to be built.

• Land Drainage Consent - for any works being carried out in a ‘main channel’


Micro-Hydropower Systems– Regulatory Requirements

Environmental Regulations

It is necessary to carry out a Environmental Site Audit (ESA) as part of the process of identifying the suitability of a micro-hydropower installation. The ESA covers the following areas:

• Water resources • Conservation • Chemical and physical water quality • Biological water quality • Fisheries • Flood risk • Navigation

The Environment Agency must always be consulted as early as possible when a micro-hydropower installation is being considered.


Micro–Hydropower Systems

How did you do?

Question Answer

Is a micro-hydropower installation classified as ‘permitted development’ under the Town and Country Planning Regulations?

No – the local planning authority must be consulted

What is an Abstraction Licence? A licence that authorises the temporary or permanent extraction of water from a water course

Which body would issue an Abstraction Licence?

The Environment Agency

What type of audit must be carried out as part of the process to decide is a micro-hydropower installation is possible?

An Environmental Site Audit






Micro–Hydropower Systems – Advantages and Disadvantages



It is a zero carbon technology Requires a watercourse with suitable head and flow



Excellent payback potential Usually requires planning permission and

Can be a very effective technology where no mains electricity is available

Requires permission from the Environment Agency

Well Done! You have now completed the micro-hydropower systems section.


Module 3: Co-generation Technologies

Module 3: Cogeneration Technologies

Micro-Combined Heat and Power Systems (Heat Led)

Objectives


• understand the fundamental working principles of a heat-led micro-combined heat and power system

• recognise the top level regulatory requirements that apply in relation to a heat-led micro-combined heat and power system installation work

• recognise the fundamental requirements of building location and building features for the potential to install to a heat-led micro-combined heat and power system

• to exist• recognise the typical advantages and disadvantages a heat-led micro-combined

heat and power system


Micro-Combined Heat and Power Systems (Heat Led) - Introduction

A heat-led micro-combined heat and power (mCHP) system includes a mCHP unit, similar in appearance to a heating system boiler, that generates some electricity as well as generating heat for domestic hot water and space heating purposes.

The term ‘heat-led’ means that the generation of the electricity occurs when the unit is responding to a system demand for heat and that the majority of output from the unit is for heating purposes.

Although mCHP units have existed for some time, units suitable for domestic installations have only recently become available. The currently available domestic units are gas-fired only. Other fuels options may be available for non-domestic units.

MCHP is a low carbon technology and the units are typically up to 95% efficient.

Typical mCHP System Energy Flows


Micro-Combined Heat and Power Unit Components

The key mCHP unit internal components are:

• an engine or gas turbine• an alternator • two heat exchangers• a supplementary burner• a combustion fan • electrical controls (not illustrated)

mCHP units can contain any of the following engine types

• External combustion (Stirling type illustrated )

• Internal combustion• Organic rankine cycle

Example mCHP Unit


Micro-Combined Heat and Power Unit Operation (Stirling Engine Unit)

When demand for heat occurs, a gas burner provides heat to the Stirling engine unit causing the Stirling engine to operate.

The Stirling engine unit includes a generator comprising a piston that moves between a copper coil. As the Stirling engine operates electricity is generated providing the engine runs for a minimum period of time and does not cycle on and off.

There is a limit (typically 25% of total unit output) to the amount of heat that can be provided during the operation of the Stirling engine.

When additional heat is needed to meet higher demand, the supplementary burner operates.


Micro-Combined Heat and Power Unit – Electrical Output and System Connections

A domestic mCHP unit will typically generate between 1kW and 1.5kW of electricity. Larger mCHP units typically generate up to 5-6 kW of electricity.

The preferred connection arrangement between the mCHP unit and the main electricity system is using a dedicated circuit from/to the consumer unit (Option 1).

Where this is difficult, it is possible to connect the unit to an existing final circuit (Option 2).

Any surplus electricity can be exported to the distribution grid. mCHP installations are eligible for Feed-In Tariff payments providing the installation is carried out by a Microgeneration Certification Scheme MCS) certified contractor using an MCS approved unit.

All electrical work must be designed, installed and tested by a competent person.


Micro-Combined Heat and Power Systems

How did you do?

Question Answer

How does a mCHP unit generate electricity? Using a generator connected to an engine or turbine

Approximately, what percentage of the energy produced by a mCHP unit is electrical energy ?

15%

What is the maximum efficiency of a mCHP unit?

95%

Are mCHP installations eligible for Feed-in Tariff payments?

Yes - providing the installation is carried out by a Microgeneration Certification Scheme MCS) certified contractor using an MCS approved unit






Micro-Combined Heat and Power Systems – Regulatory Requirements

The installation of a micro-combined heat an power system will require compliance with a number of regulatory requirements including health and safety, electrical regulations and regulations relating to the connection of ‘on-grid’ micro-combined heat and power systems. A competent installation contractor will have a detailed knowledge of these regulations and will ensure compliance.

Within this section we consider two primary regulatory requirements in relation to micro-combined heat and power systems




Micro-Combined Heat and Power Systems – Regulatory RequirementsThe Building Regulations (England and Wales) comprise of 14 parts. Eight of these parts may have relevance to micro-combined heat and power systems installation.


A Structure Where the mCHP unit and other components put load on the structure








J Combustion appliances and Fuel Storage system

mCHP units are a heat-producing combustion appliance and must be installed safely












Micro-Combined Heat and Power Systems – Regulatory Requirements


Planning permission is not normally needed when installing a micro-combined heat and power system in a house if the work is all internal. If the installation requires a flue outside, however, it will normally be permitted development if the conditions outlined below are met:

• Flues on the rear or side elevation of the building project to a maximum of one metre above the highest part of the roof.

If the building is listed or in a designated area even if the building has permitted development rights it is advisable to check with the local planning authority before a flue is fitted. Consent is also likely to be needed for internal alterations.

In a conservation area or in a World Heritage site the flue should not be fitted on the principal or side elevation if it would be visible from a highway.

If the project also requires an outside building to store fuel or related equipment the same rules apply to that building as for other extensions and garden outbuildings.


Micro-Combined Heat and Power Systems - Building location and feature requirements

For the potential to install to a micro-combined heat and power system to exist, as a minimum some or all of the following building and location factors will need to be considered:

• A suitable route and termination point for the mCHP unit flue system

• A suitable heat-demand – heat-led mCHP units only generate electricity when the unit engine is able to run for a minimum period of time. Additionally, the unit will not be as efficient if the unit cycles ‘on and ‘off’ Small dwellings and dwelling with low heat demand are not suitable for heat-led mCHP.


Micro-Combined Heat and Power Systems

How did you do?

Question Answer

Is the installation of a mCHP in a house classified as permitted development under the Town and Country Planning Regulations?

Yes providing:Flues on the rear or side elevation of the house project no more than one metre above the highest part of the roof.The house is not listed, not in a designated area not in a conservation area or in a World Heritage site

What effect does ‘on’ – ‘off’ cycling operation have on a mCHP unit?

The operation is inefficient and it is unlikely that the unit will produce electricity.

What type of heat-demand is most suitable for a mCHP system?

A high heat demand





Micro-Combined Heat and Power Systems – Advantages and Disadvantages


Well Done! You have now completed the micro-combined heat and power systems section.

Click on menu to return to the module menu.


Domestic mCHP units are now similar in size to a central heating boiler

The cost of domestic mCHP units do not compare favourably to central heating boilers

Heat-led mCHP units produce free electricity whilst generating heat

Heat-led mCHP units are not suitable for property with low heat demand

Eligible for Feed-in Tariff payments (subject to conditions)

Heat-led mCHP units have a limited electrical generation capacity

Does not rely on building orientation or weather conditions to generate renewable electricity

Unlike other renewable electricity producing technologies, mCHP is a low carbon rather than zero carbon technology

Module 4: Water Conservation Technologies


Rainwater Harvesting Systems

Objectives


• understand the fundamental working principles of a rainwater harvesting system• recognise the top level regulatory requirements that apply in relation to rainwater

harvesting system installation work• recognise the fundamental requirements of building location and building features

for the potential to install to a rainwater harvesting system to exist• recognise the typical advantages and disadvantages rainwater harvesting systems


Rainwater Harvesting Systems - Introduction

A rainwater harvesting system captures and stores rainwater for permitted non-wholesome usage.

A rainwater harvesting system reduces mains water usage.

Although not typically associated with being a low carbon technology, rainwater harvesting systems do reduce wholesome (mains) water consumption. To become ‘wholesome’ water is treated by the water supply company before it is supplied. Any reduction in usage of wholesome water will also lead to energy savings and a carbon emission reduction through a reduction in treated water consumption.


Rainwater Harvesting Systems – Permitted use of harvested rainwater

Harvested rainwater is classified as Class 5 Risk under the Water Supply (Water Fittings) Regulations 1999.

If harvested rainwater is filtered, stored correctly and used frequently, untreated harvested rainwater is suitable for use and is permitted for use for the following purposes:

• Supplying an clothes washing machine• Flushing WCs• Garden watering/irrigation• Car washing

Harvested rainwater is not suitable for use and is not permitted for use for the following purposes:

• Drinking water• Dishwashing (hand or machine)• Food preparation • Personal washing, showering bathing


Rainwater Harvesting System Layout and Key Components (Indirect distribution with below ground tank)

1

3

2 4


Click on each number for a brief overview


Rainwater Harvesting System Components - Below Ground Storage Tank

The storage tank can be located above or below ground providing the stored water is protected from freezing, warming and bacterial contamination.

Water enters the storage tank via the calmed inlet. The calmed inlet minimises turbulence and slows the flow of water into the tank

The harvested rainwater is then pumped away to the outlet points using a submersible pump.

Where possible, the submersible pump is best supplied via a floating extraction point to avoid disturbance of any sediment at the bottom of the tank.


Rainwater Harvesting System Components – Inlet filter

Before the harvested rainwater enters the storage tank it must pass through an approved type inlet filter.

The inlet filter can be located anywhere in the collection pipework but must be accessible for maintenance purposes.


Rainwater Harvesting System Components – Intermediate Storage Cistern

Harvested rainwater can be distributed directly from the storage tank or distributed via an intermediate storage cistern.

Where an intermediate storage cistern is included the arrangement shown is used.

A key requirement is the inclusion a back-up wholesome water supply. The back-up supply can be from a mains water supply or a private water supply.

Backflow of the stored rainwater into the back-up water supply must be prevented. The required backflow prevention arrangement is a Type AA air gap.


Rainwater Harvesting System Components – Signage and Labelling

Appropriate signage and labelling must be provided to minimise the risk of incorrect use of harvested rainwater and/or the possibility of cross-connections between wholesome water systems and harvested rainwater systems.

All harvested rainwater pipework systems must be suitably marked to identify its use using either approved type labels at stated maximum intervals or using pipe that is marked during the manufacturing process


Rainwater Harvesting System Layout (example direct distribution system with above ground tank)



Rainwater Harvesting System Layout Options

We have looked at example system layouts for:

• Below ground rainwater harvesting storage tank with indirect distribution system via an intermediate system

• Above ground rainwater harvesting storage tank with direct distribution system

Other storage tank and distribution system arrangements include:

• Below ground rainwater harvesting storage tank with direct distribution system

• Above ground rainwater harvesting storage tank with indirect distribution system via an intermediate system

• Above ground high-level storage tank (usually internal) with gravity distribution to outlets.



How did you do?

Question Answer

Is harvested rainwater suitable for use to supply a bath or shower?

No

What is the purpose of a Type AA air gap arrangement in a rainwater harvesting system?

To prevent backflow of stored rainwater into the wholesome water supply

Why is labelling and marking of rainwater harvesting pipework and outlets important?

To minimise the risk of incorrect use of harvested rainwater and/or the possibility of cross-connections between wholesome water systems and harvested rainwater systems.

Which component is a floated extraction connected to?

The submersible pump







The installation of rainwater harvesting systems will require compliance with a number of regulatory requirements including health and safety, water regulations . A competent installation contractor will have a detailed knowledge of these regulations and will ensure compliance.

Within this section we consider two primary regulatory requirements in relation to rainwater harvesting systems :




Rainwater Harvesting Systems – Regulatory RequirementsThe Building Regulations (England and Wales) comprise of 14 parts. Six of these parts may have relevance to rainwater harvesting systems installation.


A Structure Where rainwater harvesting system components put load on the structure and/or where excavations are made near to the structure







Water efficiency

H Drainage and Waste Disposal Rainwater gutters and rainwater pipework connected to rainwater harvesting systems

P Electrical safety in dwellings The connection of rainwater harvesting system electrical components









Rainwater Harvesting Systems – Regulatory Requirements


Planning permission is not normally needed when installing a rainwater harvesting system in a house if the finished installation does not alter the outside appearance of the property. Where above ground rainwater harvesting storage tanks are to be included, planning permission may be required.

If the building is listed or in a designated area it is advisable to check with the local planning authority before installing a rainwater harvesting system even if the building has permitted development rights . Consent is also likely to be needed for internal alterations to listed buildings.

The local planning authority should also be consulted if the property is In a conservation area or in a World Heritage site.

If the project requires an outside building to house the rainwater harvesting storage tanks same rules apply to that building as for other extensions and garden outbuildings.


Rainwater Harvesting Systems - Building location and feature requirements

For the potential to install to a rainwater harvesting system to exist, as a minimum some or all of the following building and location factors will need to be considered:

• A suitable location and space for a storage tank of a suitable size to meet the demand.

• A suitable location for rainwater harvesting system storage tank(s) to minimize the potential for freezing, warming and algal blooms

• For retrofit installations access for excavation machinery may also need to be considered.

• A suitable supply (yield) of rainwater in relation to the demand on the system. Rainwater harvesting systems are not suitable for areas with a low rainfall intensity or suitable for buildings with a small rainwater catchment area.

• The availability of a wholesome back-up water supply



How did you do?

Question Answer

Why is Part A of the Building Regulations relevant to the installation of a rainwater harvesting system?

Because the load imposed by system components such as storage tanks and cisterns may affect the structure of the building. Also, any excavation work may have an effect on the structural stability of the building.

Is planning permission normally required for a rainwater harvesting system installation?

Not normally unless the storage tank is above ground or unless the building is listed or located is a conservation area or similar type of area.

Is a rainwater harvesting system suitable for a building that is located in an area with low rainfall intensity?

No





Rainwater Harvesting Systems – Advantages and Disadvantages



Conserves wholesome water Payback periods can be long.

Indirectly reduces energy consumption and reduces carbon emissions

Not always straightforward to install to existing building

A wide range of system options exist There is a risk of contamination or cross-connection

Rainwater is free so for buildings where a water meter is fitted the annual cost of water will reduce

Only certain types of outlet and appliance can be supplied using harvested rainwater

Well Done! You have now completed the rainwater harvesting systems section.

Click on the forward arrow to return to the water conservation technologies menu page


Greywater Re-use Systems

Objectives


• understand the fundamental working principles of a greywater re-use system• recognise the top level regulatory requirements that apply in relation to greywater

re-use system installation work• recognise the fundamental requirements of building location and building features

for the potential to install to a greywater re-use system to exist• recognise the typical advantages and disadvantages for greywater re-use systems


Greywater Re-use Systems - Introduction

A greywater re-use system captures and stores ‘grey’ waste water that is discharged from washbasins, baths, showers washing machines and kitchen sinks for permitted non-wholesome usage

A greywater re-use reduces mains water usage.

As with rainwater harvesting systems, greywater re-use systems are not typically associated with being a low carbon technology, greywater re-use systems do reduce wholesome (mains) water consumption. Any reduction in usage of wholesome water will also lead to energy savings and a carbon emission reduction through a reduction in treated water consumption.


Greywater Re-use Systems – Permitted use of reclaimed greywater

Greywater is classified as Class 5 Risk under the Water Supply (Water Fittings) Regulations 1999.

If greywater is filtered, stored correctly and used frequently and where necessary treated, greywater is suitable for use and is permitted for use for the following purposes:

• Flushing WCs• Garden watering/irrigation• Car washing • Supplying an clothes washing machine (if appropriately treated)

Greywater is not suitable for use and is not permitted for use for the following purposes:

• Drinking water• Dishwashing (hand or machine)• Food preparation • Personal washing, showering bathing


Greywater Re-use Systems – Types of system

System Type Description

Direct re-use system A system that collects greywater from appliances and delivers it directly to the points of use with no treatment and minimal, or no storage.

Short retention system

A system that includes a basic filtration or treatment technique such as surface skimming and allow for natural particle settlement.

Basic physical/chemical system

A system that filter s greywater prior to storage and uses chemical disinfectants such as chlorine or bromine to stop bacterial growth during storage

Biological system A system that introduces an agent, such as oxygen, into the stored greywater to allow bacteria to digest any unwater organic mater. Pumps or plants can be used to aerate the stored water.

Bio-mechanical system

A system that combines both physical and biological treatment.

Hybrid system A combination of any of the above systems or a combiner rainwater harvesting and greywater re-use system.


Greywater Re-use Systems – Storage, Treatment and Use Considerations

Greywater from showers, baths and washbasins will often be contaminated with human intestinal bacteria and viruses as well as organic debris such as skin particles and hair.

Greywater will also contain residues of soaps, detergents and other cosmetic products; these often contain nutrients that help bacteria develop. This combination of bacteria, organic material and nutrients provides ideal conditions for bacteria to grow. The relatively high temperature of greywater can also encourage the growth of bacteria further.

For these reasons untreated greywater should never be stored for more than a few hours.

If greywater is to be used for irrigation, it should be directly applied to soil and not through a sprinkler or method that would allow contact with above ground portions of plants.

Greywater should not be used to water crops, which are eaten uncooked. It is recommended that greywater should not be applied to seedlings or young plants.


Example Greywater System Layout and Key Components



Greywater Re-use System Layout Options

We have just looked at an example layout for a below ground greywater re-use storage tank with indirect distribution system via an intermediate storage cistern system

A wide range of other system layout options exist including a number of options for an internal greywater storage tank and treatment unit. The internal units come in a variety of shapes and sizes and offer a lot of flexibility in system design.

As with rainwater harvesting systems, all greywater re-use system supply points and pipework must be marked and labelled to minimise the risk of incorrect use of reclaimed greywater and/or the possibility of cross-connections between wholesome water systems and greywater re-use systems.



How did you do?

Question Answer

Is reclaimed greywater suitable for use to supply a clothes washing machine?

Yes if it is appropriately treated before use. (appropriate treatment is likely to be a combination of membrane filtration, anaerobic bacteria and ultra-violet disinfection)

What is a direct reuse greywater system ? A system that collects greywater from appliances and delivers it directly to the points of use with no treatment and minimal, or no storage.

Is reclaimed greywater suitable for use to water vegetables that will be eaten uncooked?

No, this type of use is not recommended






The installation of greywater re-use systems will require compliance with a number of regulatory requirements including health and safety, water regulations . A competent installation contractor will have a detailed knowledge of these regulations and will ensure compliance.

Within this section we consider two primary regulatory requirements in relation to greywater re-use systems :




Greywater Re-use Systems – Regulatory RequirementsThe Building Regulations (England and Wales) comprise of 14 parts. Six of these parts may have relevance to greywater re-use systems installation.


A Structure Where greywater re-use system components put load on the structure and/or where excavations are made near to the structure







Water efficiency

H Drainage and Waste Disposal Sanitary pipework connected to greywater re-use systems

P Electrical safety in dwellings The connection of greywater re-use system electrical components









Greywater Re-use Systems – Regulatory Requirements


Planning permission is not normally needed when installing a greywater re-use system in a house if the finished installation does not alter the outside appearance of the property. Where above ground greywater re-use storage tanks are to be included, planning permission may be required.

If the building is listed or in a designated area it is advisable to check with the local planning authority before installing a greywater re-use system even if the building has permitted development rights . Consent is also likely to be needed for internal alterations to listed buildings.

The local planning authority should also be consulted if the property is In a conservation area or in a World Heritage site.

If the project requires an outside building to house the greywater re-usestorage tanks same rules apply to that building as for other extensions and garden outbuildings.


Greywater Re-use Systems - Building location and feature requirements

For the potential to install to a greywater re-use system to exist, as a minimum some or all of the following building and location factors will need to be considered:

• A suitable location and space for a storage tank of a suitable size to meet the demand.

• A suitable location for greywater system storage tank(s) to minimize the potential for freezing, warming and algal blooms

• For retrofit installations access for excavation machinery may also need to be considered.

• A suitable supply (yield) of greywater in relation to the demand on the system. Greywater re-use systems are not suitable for buildings with a low volume of greywater discharge.

• The availability of a wholesome back-up water supply



How did you do?

Question Answer

Why is Part H of the Building Regulations relevant to the installation of a greywater re-use system?

This part of the Building Regulations states the requirements relating to the design, installation and testing of sanitary pipework connected to greywater re-use systems.

Is planning permission normally required for a greywater re-use system installation?

Not normally unless the storage tank is above ground or unless the building is listed or located is a conservation area or similar type of area.

Is a greywater re-use system likely to be suitable for a property with two occupants who prefer to take sort showers instead of baths?

Not typically because the volume (yield) of available greywater is likely to be insufficient to make the system viable. However, some small-scale greywater systems may be suitable.





Greywater Re-use Systems – Advantages and Disadvantages



Conserves wholesome water Payback periods can be long.

Indirectly reduces energy consumption and reduces carbon emissions

Not always straightforward to install to existing building

A wide range of system options exist There is a risk of contamination or cross-connection

Greywater is free so for buildings where a water meter is fitted the annual cost of water will reduce

Only certain types of outlet and appliance can be supplied using reclaimed greywater

Well Done! You have now completed the greywater re-use systems section.

Click on the forward arrow to finish

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