Electricity smart lighting: Reducing energy costs in agri-buildings

Brochure

ighting is often one of the most overlooked opportunities for saving energy in the agricultural sector. Farms can significantly reduce energy consumption and, therefore, cut operating costs with a comparably low investment in energy-efficient lighting technologies.

Energy-smart lighting in agri-buildings reduce energy costs

The most common types of lamps used in agricultural sector buildings such as barns, warehouses and greenhouses are incandescent lamps, T-12 fluorescents and High Intensity Discharge (HID) lamps, such as Mercury Vapour and High-Pressure Sodium lamps.

All of these lighting systems, with the exception of energy-efficient High-Pressure Sodium lamps, are energy-intensive and use more electricity than new generation lighting technologies.

Energy-efficient lights save money and more

New generation lighting systems use less electricity, are kinder to the environment and generally have a longer lifespan than older lighting technologies. Switching to energy-efficient lights has tremendous potential to reduce greenhouse gas emissions - the Carbon Dioxide (C0²) emission reduction potential of energy-saving lights has been estimated at about 15 mega tons (European Energy Commission).

The large variety of components available today means there are energy-efficient lighting solutions for almost any context and purpose. Different applications and tasks have different lighting requirements, which will dictate the light intensity (lumens or foot candles), degree of whiteness and colour rendering required from lamps; the best lighting provides the optimal amount and type of light to best perform a task or increase productivity at the minimum annual cost (operating and fixed costs).

Role of lighting in buildings

It’s important to understand the role that lighting plays in an agricultural setting. The primary function of light and lighting is to see - artificial lighting enables indoor work and activity around the clock every day.

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In agri-commerical buildings, lighting plays a significant role in animal and plant productivity whilst colour rendering (how well light reproduces colour) and illumination (the amount of light received on a surface) influence the way people feel and perceive colours, and how they experience thermal comfort.

Studies on the influence of both artificial and natural lighting have shown that people are more energetic and productive when they’re exposed to daylight and when they work in an appropriately lit environment.

The amount of light or illumination (measured in lux) required depends on the activities planned for a building. For instance, more lux is needed for intricate tasks such as working with small parts than is required for cleaning.

From a lighting point of view, illumination is the most important factor because of the role that lighting plays in behaviour and productivity. However, from an energy-savings perspective, luminous efficacy (the ratio between input energy and the light emitted) is crucial.

Lumen (lm) - the measurement of the power of light emitted by a given source and perceived by the human eye.

Luminous efficacy/efficiency - the measure of a lamp’s ability to convert electric power into visible light (expressed in lumen/watt (lm/W)).

Colour Rendering Index (CRI) - on a scale of 0 to 100, the measurement of how well a lamp renders colour.

A lamp with a CRI of 100 makes objects appear as they do in sunlight. All lamps have various characteristics in terms of colour rendering. Various systems can, therefore, be more or less appropriate for a given application in an agri-commercial building.

It is estimated that lighting is responsible for between 35 and 45% of monthly energy consumption in agri-commercial buildings.

Energy-saving lighting options in the agricultural sector

T-8 fluorescent lampsThe fixtures for T-8 lamps look similar to the commonly used T-12 lamps, except that the T-8 bulbs are smaller in diameter. A T-8 lamp provides about 15% more lumens per bulb and its ballast is 40% more efficient than a T-12’s ballast. • Most standard T-8 ballasts can start in cold temperatures. • T-8 lamps use electronic ballasts that operate at high frequency and eliminate the flicker associated with T-12 electromagnetic ballasts when ambient air temperatures are cooler. • Electronic ballasts are available for T-12 fixtures. If the correct dust - and moisture-resistant fixtures are used, T-12 fixtures can be converted to use T-8 lamps by replacing the lamps and ballasts (the same sockets are used for both lamps). • T-8 lamps have a lifespan of about 20,000 hours.

T-5 fluorescent lamps T-5 lamps are approximately 40% smaller in diameter and also slightly shorter than T-8 lamps. They cannot, therefore, be used as a replacement for the larger lamps.• Some luminaires, however, accept either T-5 or T-8 lamps by changing the sockets and ballasts. • T-5 lamps are available for standard output and high output and are the most energy-efficient compared to T-12 and T-8 fluorescents.

It is important to look at the application and cost benefits of T-5 over T-8 lamps to determine if the increased efficiencies of T-5s justify the substantial increase in initial and long-term maintenance costs.

Compact Fluorescent Lamps (CFLs)CFLs are direct replacements for incandescent lamps because they have a similar medium screw base. • They use up to 75% less electricity whilst providing the same amount of light - their Colour Rendering Index and correlating colour temperature are similar to that of incandescent lamps.• Their lifespan is about 6,000 to 10,000 hours, which means they last from six to 10 times longer than incandescent lamps.

CFLs today are second generation technology and are available in a bigger range of compact sizes to suit a variety of applications - they can take a few minutes to warm up to full output in low ambient temperatures.

Standard CFLs should not be used in livestock housing unless installed in sealed fixtures. Some lighting manufacturers have already developed specialised CFLs for use in livestock housing.

Light Emitting Diodes (LEDs)LEDs use less electricity to operate and produce more light per watt than most other light sources. • They are about 70 to 85% more energy-efficient than conventional incandescent lamps and more efficient than Compact Fluorescent Lamps (CFLs). • LEDs have a colour temperature (warmth) comparable to that of incandescent lamps and produce full lighting capacity as soon as they are switched on. They start up quickly and turn off immediately so there is no fading as the lamp cools down.

Generally, LEDs can last up to five times longer than CFLs, which last about six times longer than incandescent lamps. LEDs do not burn out or fail - instead, they experience lumen depreciation, with the amount of light produced decreasing and light colour appearance shifting over time.

LEDs are available in a range of sizes and shapes for a variety of applications and offer impressive flexibility in colour and light distribution - some are directly compatible drop-in replacements for incandescent or fluorescent lamps.

LEDS have standard lamp connections and shapes, such as:• An Edison screw base• An MR16 shape with a bi-pin base • A GU5.3 (bi-pin cap)• A GU10 (bayonet fitting).

A note on power factor:An overall power factor at a point of supply of less than one can result in the following problems:• Harmonics from lamps could degrade the sine wave of the Alternating Current electricity supply and affect the performance of other equipment on the same feeder• More current in transmission lines can lead to more power loss in the form of heat and, therefore, wasted energy• When purchasing a CFL or LED, make sure to check that the power factor is specified and displayed on the packaging - cheaper lights will not have it specified. With quality lamps, harmonic filters are built in to mitigate the problems associated with low power factor.

Metal Halide lampsMetal Halide lamps provide good colour rendering and are an effective replacement for Mercury Vapour lamps in areas where colour recognition is important, such as in a dairy parlour.• Metal Halide lamps are available in a standard version and a pulse-start version - pulse-start is newer technology that results in up to 50% longer lamp life, about 8% more lumens per watt, faster warm up and restarts and up to 33% less lumen depreciation over the lamp life.

Pulse-start Metal Halide lamps are not interchangeable with standard Metal Halide lamps because a different ballast is required - if you are adding new fixtures to an existing installation it is recommended that all fixtures be upgraded to pulse-start ballasts and lamps to eliminate inventory issues.

A Mercury Vapour lamp is the least efficient of the High Intensity Discharge (HID) lamp types and poses a greater environmental risk than High-Pressure Sodium (HPS) and Metal Halide (MH) lamps.

Lighting controlsProgrammable lighting control systems can limit electricity wastage by controlling when and how light is emitted where needed in agri-commercial buildings - systems can switch lights off automatically or reduce lighting levels according to occupancy or night time security requirements.• Occupancy sensors control lighting based on occupant detection in intermittently occupied areas such as storerooms. • Daylight sensors brighten, dim or even switch off lights according to changing natural light levels. • Sensors can be positioned on walls, corners or ceilings to provide the best detection area for each application.

Considering lighting options for agri-commercial buildings

Warehouses, barns and dairy parlours • For lighting in a warehouse or barn with ceilings as high as 12 to 20 feet, a low-bay Metal Halide fixture would be suitable for a wide distribution pattern - this type of fixture is usually equipped with a diffuser to spread light horizontally. • In a barn, lights can be controlled by photo sensors or a time clock.• T-8 fixtures designed for wet and dusty environments are required for lighting barns, parlours and milk rooms.

Different lighting fixtures distribute light in different ways - consult a lighting specialist to calculate the correct spacing and mounting height for a fixture in a particular barn, warehouse or dairy parlour layout.

A reputable lighting specialist will have access to lighting design software that considers the size of the space to be lit, the reflectance values of the internal surfaces and lamp mounting height.

Greenhouse lighting Supplemental lighting for plant growth can decrease growing times and reduce the risk associated with low levels of sunlight - plant growth is directly related to the amount of light energy received on leaf surfaces.

Different plant species have different saturation levels for the amount of light energy they can absorb. Above this level, additional light will not increase plant growth.

A range of lighting technologies can be used in greenhouses, such as Compact Fluorescent Lamps (CFLs), Light Emitting Diodes (LEDs) and High Intensity Discharge (HID) lamps. CFLs and High-Pressure Sodium and Metal Halide Lamps are the most widely applied by indoor vegetable and flower growers. CFLs and LEDs are, however, replacing Metal Halides due to their superior energy efficiency and cost effectiveness. Moreover, recent advances in power efficiency and optimised light spectra show that high-powered LED systems can produce improved yields.

It is important to ensure that suitable energy-efficient lighting technologies are selected for your greenhouse in terms of light levels, colour rendering and warmth - consult a lighting specialist for assistance.

Pretorius Blomme cuts energy costs Pretorius Blomme in Delmas has dramatically reduced operating costs by overhauling lighting in its greenhouses. Switching from incandescent bulbs to energy-saving Compact Fluorescent Lamps (CFLs), the company has reduced energy consumption by 50,000 kilowatt-hours annually.

1,000 incandescent lights were replaced with 20W ‘warm white’ spiral CFLs to achieve the required 70 lux at flower level.

This resulted in a 100kW to (almost) 20kW reduction in the wattage required for greenhouse lighting at Pretorius Blomme.

General lighting For lighting in public areas, storage facilities and offices in your agri-business, replace all conventional incandescent bulbs with Compact Fluorescent Lamps (CFLs) or Light Emitting Diodes (LEDs).

Regulations

Owners and managers of agri-commercial buildings should take note of the lighting regulations set out in SANS 10114-1 and the Occupational Health and Safety (OHS) Act of 1993.

SANS 10114 provides basic guidelines and recommendations for the creation of good viewing conditions and a comfortable visual environment. Although the recommendations are primarily intended for interior workplaces, they also apply, in general, to other interior locations. The visual environment should be such that essential task details are easily visible and that adverse factors, which can cause visual discomfort, are appropriately controlled or excluded.

Although SANS 10114 recognises the need for good energy management and cost-effective lighting schemes, this should not lead to the lowering of the recommended standards needed to promote efficient work, safety and welfare.

Revisions, amendments and affirmations of SANS 10114-1 are conducted periodically to keep pace with international developments in lighting and lighting products and to apply guidance from international standardisation bodies such as CIE, IEC, ISO and others.

Extract from the Occupational Health and Safety (OHS) Act, 1993:• Every employer shall cause every workplace in his undertaking to be lit in accordance with the illuminance values specified in the Schedule to these regulations: Provided that where specialised lighting is necessary for the performance of any particular type of work, irrespective of whether that type of work is listed in the Schedule or not, the employer of those employees who perform such work shall ensure that such specialised lighting is available to and is used by such employees.

For detailed information visit:www.labour.gov.zawww.sabs.co.za

More tips for energy efficient lighting:• Replace conventional control gear with electronic control gear - the switch to electronic high-frequency ballasts can lead to an increase from 30 to 40% in system efficiency • Remove unnecessary lamps and ballasts in over lit areas, which can be identified by measuring the amount of illumination - lighting can be reduced where illumination exceeds set standards and recommendations for specific tasks and applications in your agri-business • Match light provided with demand - lighting control technologies such as motion and daylight sensors limit electricity wastage by controlling when and where light is provided.• Use the correct lamp reflectors and make sure they are properly maintained to ensure optimal light output. • Regularly maintain lighting systems, especially in environments where there is a lot of dust, high levels of humidity and chemically aggressive vapours and gases• Regularly clean light diffusers to improve light output levels and efficacy.

Energy assessment

Before commencing with any lighting retrofit or replacement in an agri-commercial building or facility, first conduct an energy assessment to help you prioritise energy-saving initiatives based on:• Available budget• The cost and availability of technologies • The scale of your envisaged retrofit or replacement • Its feasibility in the framework of your operation.

Eskom Energy Advisors

Eskom’s national Advisory Service offers information on manufacturers and suppliers of energy-efficient lighting. The team can also advise agri-businesses on:• Reducing energy usage• Doing walk-through energy assessments to identify energy usage patterns, energy needs, areas of energy wastage and energy-saving opportunities• Improving the energy efficiency of operations and electrical systems and processes • Prioritising maintenance as an important contributor to reducing energy usage• Finding SANAS approved Measurement & Verification Authorities.

Advisors can also provide information on funding opportunities for energy efficiency projects.

Call 08600 37566, leave your name and number and an Eskom Energy Advisor will contact you. Alternatively, ask for a specific advisor to contact you.

Visit www.eskom.co.za/idm for more information.

Credits:http://learningstore.uwex.eduwww.carbontrust.comwww.wikipedia.com

Issued by Eskom Integrated Demand Management November 2015Eskom Holdings SOC Ltd Reg No 2002/015527/30