Energy efficient ventilation solutions

Paul Compton

I J O’Hea,Colt Founder

A private company founded in 1931

I J O’Hea OBE (1897 - 1984)

2013 Group turnover £152 million

Manufactures in the Brazil, China, the Netherlands, Saudi Arabia, the

UK and the USA

A brief history of Colt

Current UK Business markets

Smoke Control

Solar Shading

Natural Ventilation

Louvre

Environmental Comfort Control

Programme

Introduction

Natural ventilation

Mechanical ventilation

Cooling

PIATRA

INTRODUCTION

Environmental Control Requirements – Natural AOVWhat’s important to you?

•First cost

•Running cost

•Total cost of ownership / life cycle costing

•Carbon (total or embodied)

•Energy (total or embodied)

Environmental Control Requirements – Natural ShaftsEmbodied energy and carbon

•Accurate information is very difficult to get

•Manufacturers haven’t grasped the nettle

•For most systems it’s outweighed by energy in use

•Aluminium 1tCO2/t recycled, 3-20tCO2/t raw

INTRODUCTION

Environmental Control Requirements – Natural ShaftsFirst cost

•Mechanical ventilation – low cost = high energy and carbon in use?

•Natural ventilation – low cost = low energy and carbon?

•Our industry makes first cost so important - specifications are critical

•Approved document L and the associated building services guides?

INTRODUCTION

Environmental Control Requirements – Natural ShaftsRunning cost and total cost of ownership

•Important to the occupier but not necessarily to the builder

•Soft Landings can help by at least getting the systems set up properly, but if the design is inherently inefficient ……...

•Reduce loads by solar control, tight building, low energy lighting, limiting plug loads, etc

INTRODUCTION

Environmental Control Requirements – Natural Shafts- If you really want low energy and carbon

•Generally simple, lightweight systems, therefore with low embodied energy and carbon

•Virtually no energy use in operation

•But in heated buildings there will be extra winter energy use to counteract the extra fabric and ventilation heat losses – these can be significant

NATURAL VENTILATION

Environmental Control Requirements – Natural ShaftsSo why are all buildings not naturally ventilated?

•Conditioning of the incoming air is generally not possible

•Close control of internal conditions is generally not possible

•Noise control can be difficult

•Building form may not suit natural ventilation

•Controls need to be well thought through and designed

•Lack of experience/confidence

NATURAL VENTILATION

Environmental Control Requirements – Natural ShaftsEnergy and carbon

•Take a simple example of a heated and naturally ventilated DIY store requiring roof ventilators with 40m2 aerodynamic area

•Consider 2 options: Colt Seefire or Colt Firelight

NATURAL VENTILATION

Seefire Firelight

U value 3.5 1.2

Leakage (m3/h/m2 at 50Pa

170 7

Installed cost £19 000 £30 500

NATURAL VENTILATION

Environmental Control Requirements – Natural Shafts

•The embodied energy and carbon of a fan are probably similar to those of an equivalent natural ventilator but we also have:

ducting, controls, wiring, etc

•Running costs: every kWh typically costs 10p. At an SFP of 1.5 that’s 15p per hour per m3/s air flow – and there are 8760 hours per year

•With a typical UK power generation mix that equates to 670 kgCO2 and £150 per m3/s per 1000 hours running time.

MECHANICAL VENTILATION

Environmental Control Requirements – Natural ShaftsHow can we minimise energy use?

•Don’t over estimate the required flow rate

•Limit usage by mixed mode ventilation

•Reconsider duct sizing

•Make ducts as low resistance as possible – simple layouts, minimum bends, tuning vanes or radiused bends, etc and minimise duct leakage

•Choose efficient fans

•Use VSD control if practical

•Consider EC motors for smaller fans

MECHANICAL VENTILATION

Environmental Control Requirements – Natural ShaftsEnergy and carbon

Take the previous example

•Consider the option of using mechanical extract instead

•55 m3/s extract at 0.5 SFP (roof units)

•Initial cost £24000 Running 1000 hours p.a. (summer daytime)

•£2750 p.a. electrical cost, 4500 kgCO2

•Winter heat losses £1300 p.a., 12000 kgCO2

•Overall

•“good” natural ventilation system gives 2 year payback

•“good” natural ventilation system reduces CO2 emissions by 9500 kg p.a.

MECHANICAL VENTILATION

Environmental Control Requirements – Natural ShaftsEnergy and carbon

•Three options: refrigerant, adsorptive, adiabatic

•Very different performance and total cost of ownership

•Refrigerant cooling has a high cost but is well established and provides excellent control of conditions

•Adiabatic provides virtually free cooling, but has limitations

COOLING

Environmental Control Requirements – Natural ShaftsAdiabatic cooling

•Operates by evaporation of water, converting sensible heat to latent heat and thus reducing the dry bulb air temperature

•Only operating cost/energy is fan and water pump power. No refrigerants.

•Ideal for providing cooling under peak conditions when simple mechanical ventilation is insufficient

•Limitations:

•System LAT floats with incoming air temperature and humidity

•Cannot dehumidify

•Increases humidity, needs a high percentage FAI

COOLING

COOLING

COOLING

Environmental Control Requirements – Natural ShaftsComparison of carbon and ownership costs

•A proprietary Colt program (not available for external use)

•Uses Meteonorm local hourly weather data

•Designed to compare systems, not to give accurate running cost forecasts

•Allows comparison of more than just first cost for Colt systems

•Used to provide the comparisons in this presentation

PIATRA

PIATRA

PIATRA

PIATRA

Design

Commissioning

MaintenanceEquipment/Controls

Installation

The End