Energy-efficient farm lighting

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Effective lighting does more than just illuminate an area. It can reduce running costs and improve the working environment, safety and aesthetics. Energy use associated with lighting systems can be reduced by up to 82 percent if energy-efficient lighting practices are adopted (NSW Office of Environment and Heritage, 2013).

Lighting applications on farms range from farmhouses, workshops and warehouses to large-scale use in intensive production facilities.

Indoor lighting for farm facilities is critical to safe and efficient production. Lighting systems should be designed to meet minimum lighting requirements in the most energy-efficient and economical manner. This paper gives an overview of lighting types suitable for use in farm facilities.

Energy savings through lighting

There are two general types of upgrades: retrofitting and an entire replacement. A retrofit changes only part of an existing lighting system, such as the lamps or control gear. Or you can replace the entire luminaire with a new luminaire.

The decision you make will depend on a number of factors. Generally, retrofitting requires less up-front capital and installation is relatively easy; however, installing a new luminaire is often more cost-effective in buildings containing older equipment. Full replacement can also be economical where technology advancements have led to price reductions .

Lighting upgrades

The following solutions require capital investment and could be undertaken as part of a site-wide lighting upgrade.

Fitting reflectors. Installing light fittings with reflectors that direct light to specified areas and do not absorb too much light can improve efficiency by up to 40 percent.
Installing efficient ballasts. Around 20 percent of the total energy used in fluorescent systems is lost in heat from the ballast. By installing low-loss ballasts for fluorescent lighting, you can make substantial savings in energy costs.
Installing energy-efficient lighting systems. Induction high bays can be replaced by metal halide high-bay lights; incandescent globes by CCFL.

Common lighting terminology

Luminaire. Also referred to as a light fitting or fixture, the luminaire includes the lampholder and the lamp itself.

Lampholder. A part of the luminaire that provides electrical connection to the lamp and holds the lamp in place.

Lamp. The light source mounted within a luminaire.

Control gear. The mechanism that converts the energy supplied to the building into a form that best suits the light source. Control gear includes starters and ballasts.

CRI. The Colour Rendering Index (CRI) is a measurement of a light source's accuracy in rendering different colours when compared to a reference light source with the same correlated colour temperature. CRI generally ranges from 0 for a source like a low-pressure sodium vapour lamp to 100 for a source like an incandescent light bulb.

Types of lighting

Incandescent lamps

Incandescent lamps are the least expensive and until recently, were the most commonly available lamps. An incandescent lamp creates light by using electrical resistance to heat a finely coiled wire to the point where the coil is hot enough to glow. They are also the least efficient form of lighting, however. About 90 percent of the energy used by an incandescent lamp becomes heat; only 10 percent becomes light.

General lighting service incandescent lamps (GLS lamps) are no longer available to purchase thanks to their poor efficiency, so farm facility operators must look for alternatives when replacing or upgrading such lighting.

Halogen lamps

Tungsten-halogen (or just halogen) lamps are a type of high-pressure incandescent lamp that is more energy-efficient than regular incandescent lamps. Halogen lamps operate at very high temperatures and use less energy because they recycle heat to keep their filaments hot, thus using less electricity.

Linear fluorescent lamps

Often, linear fluorescent lighting is used in shops, barns, and other covered spaces. The most common designations for linear fluorescent lighting include T-5, T-8 and T-12. The T indicates the shape of the lamp tube and the corresponding number indicates the tube diameter in eighths of an inch. A T-8 lamp is tubular and 8/8” (one inch) in diameter.

T-8 (usually 75 to 98 lm/W) lamps are the most energy-efficient option and are commonly used in farm applications. Compared to a T-12 lamp and ballast, a T-8 fluorescent lamp provides about 15 percent more lumens per watt, and its ballasts are 40 percent more efficient. Both T-8 and T-12 lamps can be used in the sealed fixtures needed in most farm applications.

Although T-5 lamps are even more efficient than T-12 and T-8 lamps, they produce more heat than larger-diameter lamps and can’t be used in sealed fixtures. Sealed and weatherproof fixtures are necessary in many areas, such as those with livestock, moisture and/or dust. For these reasons, T-5 lamps are generally not recommended for agricultural applications.

Most types of magnetic ballast (used with T-12 lamps) have not been manufactured since 2010. They can be replaced with higher-efficiency electronic ballasts or with more efficient fixtures and lamps such as the T-8.

Compact fluorescent lights (CFLs)

CFLs can be used to replace incandescent bulbs directly because they require no wiring changes. Typically, CFLs use
75 percent less energy than incandescent bulbs and last approximately 10 times longer. Normally they will not operate below -17°C and require about a minute to reach full light output. CFLs installed in livestock and poultry facilities should be rated for damp environments; however, bulb life may be shortened if you place them in globes or enclosures, due to increased temperatures. CFLs are best suited for facilities in which lights stay on for extended periods, since frequent on/off cycles shorten their lifespan.

Induction lamps

These lamps are similar to fluorescent lamps except that they do not receive their energy by electrodes creating an arc. The mercury in a typical induction lamp is excited into producing light by the use of a powerful magnetic field. The lamps are operated by electronic control gear.

High-intensity discharge (HID) lamps

HID lamps include metal halide and high-pressure sodium vapour lamps. Usually, HIDs are easy to install and maintain and are well suited for high bay applications (i.e. ceilings higher than 12 feet). However, they require a few minutes to warm up before they reach full light output so they are not ideal for short-cycle lighting. They should be replaced when light output begins to fade appreciably or when they shut off and restrike continually while power is still on.

Metal halide (MH) lamps

These bulbs generally have efficiency ratings between 60 and 80 lm/W and are available in a pulse-start or standard version. Typically, pulse-start bulbs are more efficient and can have 50 percent more lamp life than the standard version.

MH are not instant-on lights; they require one to three minutes to reach full light output. They must also cool down for five minutes before re-starting.

High-pressure sodium vapour (HSPV) lamps

HPSV lighting is more efficient than metal halide lighting. However, these lamps emit a yellow-orange light that may not be desirable for livestock facilities where true colour observation is critical to monitoring animal health. They work well at cold temperatures and are typically used outdoors.

Light-emitting diodes (LEDs)

LEDs use semiconductors (diodes) to produce light. They are up to five times more efficient than incandescent lighting and are long-lasting, with ratings up to 100,000 hours. LEDs emit directional lighting rather than the 360-degree illumination provided by other bulbs. Currently, they have limited application in livestock and poultry housing due to their susceptibility to moisture, heat and dust. New LED products are being developed, however, and some have been tested successfully in broiler housing.

Figure 1: Poultry shed using newer LED tube lighting technologies.

NSW Farmers

The following table shows a list of some of the lighting technologies that are available for farm applications. Important details to consider are lumens per watt and application types for any candidate lights.

Table 1: General characteristics of light sources used for farming facilities (Kindberg, 2010).
Lamp type	Lumens per watt	Average rated life (hrs)	Colour	CRI	Instant on (mins)	Ballast	Minimum start temp. (°C)	Application
Standard incandescent	5–30	750–4,000	White	98–100	Yes	No	Below -18	Indoor/outdoor
Tungsten halogen	12–25	2,000–6,000	White	98–100	Yes	No	Below -18	Indoor/outdoor
Compact fluorescent	50–80	6,000–12,000	White	65–95	Yes	Yes	10	Indoor/outdoor, poultry houses, storage rooms and general lighting
Cold cathode compact fluorescent	41–49	18,000–25,000	Bluish to white	82–84	Yes	Internal	-24	Indoor/outdoor, poultry and general lighting
T-12 fluorescent	75–98	6,500–20,000	White	52–95	Yes	Yes	10	Indoor, milking parlours, milk rooms, storage rooms and bay areas
T-12 high- output fluorescent	75–98	6,500–20,000	White	70–95	Yes	Yes	-30	Indoor, milking parlours, milk rooms, storage rooms and bay areas
T-8 fluorescent	75–98	7,500–20,000	White	52–95	Yes	Yes	-18	General area lighting of all kinds and low-bay areas
T-8 high-output fluorescent	75–98	6,500–20,000	White	70–95	Yes	Yes	-30	Indoor, milking parlours, milk rooms, storage rooms and bay areas
Induction	50–90	60,000–100,000	White	80–90	Yes	Yes	-40	Where maintenance costs are high
Quartz pulse-start metal halide	60–80	5,000–20,000	Bluish	65–75	No (1–3)	Yes	Below -18	Indoor/outdoor, including high-bay and greenhouses
Ceramic pulse-start metal halide	60–80	20,000	Bluish	85–94	No (1–3)	Yes	Below -18	Indoor/outdoor, including high-bay and greenhouses
High-pressure sodium vapour	50–140	15,000–24,000	Yellowor orange	20–80	No (3–5)	Yes	Below -18	Indoor/outdoor, poultry sheds, livestock holding areas and greenhouses
Low-pressure sodium	60–150	12,000–18,000	Yellow	-44	No (7–15)	Yes	Below -18	Indoor/outdoor, general and security
Mercury vapour	25–60	16,000– 24,000	Bluish	50	No (7–15)	Yes		Outdoor
Light-emitting diode	4–150	35,000–50,000	White	80–90	Yes	‘Driver’	NA	Indoor/outdoor

Notes:

Average rated life may vary depending on how often the lamp is switched on and off, and the operating environment.
Minimum start temperatures may vary depending on the lamp and ballast combination.

Light levels

Australian lighting standards outline minimum luminance requirements for farms and businesses. Sufficient lighting from a natural or artificial source must be provided to meet these standards, which have been created to allow safe movement around the workplace and to allow workers to perform their jobs without having to adopt awkward postures or strain their eyes to see. Correct lighting must also be provided for the safe and healthy farming of animals and produce. For example, lighting is an essential component of successful commercial poultry production.

Table 2: Typical recommended lighting levels for various agricultural applications.
Application	Lighting (lux)
Young chickens (1–5 days old)	24 hours constant light at 40 lux* minimum with 5–60 minutes blackout training
Young chickens (6–10 days old)	23 hours constant light at 30 lux
Pullets	15 hours constant light at 5 lux
Layers	15 hours constant light at 10 lux
Broilers	23 hours constant light at 40 lux 1–5 days, then 23 hours constant light at 3–5 lux, or alternate 2 hours light at 5 lux, 2 hours dark
Other birds
Ducks and geese	15 hours constant light at 10 lux
Pheasant breeders	15 hours constant light at 10 lux from January to end of breeding season (about April)
Occupational health and safety (Safe Work Australia, 2011)
Corridors; cable tunnels; indoor storage tanks; walkways	40 lux
Waiting rooms; entrance halls; canteens; rough checking of stock; rough bench and machine work; general fabrication of structural steel; casting concrete; automated process monitoring; turbine halls	160 lux
Routine office tasks (e.g. reading, writing, typing, enquiry desks)	320 lux
Fine inspection; plant retouching; fine manufacture; grading of dark materials; colour matching of dyes	800 lux

Case study: Victorian poultry farm lighting upgrade (ANL Lighting, n.d.)

Australian poultry farms typically used 75-watt incandescent globes to perform the invaluable role of controlled lighting to stimulate bird growth and egg production until a ban on the sale of inefficient incandescent globes started growers looking for more efficient forms of lighting.

The latest replacement globes to undergo trials are Micro-Brite Cold Cathode Fluorescent Lamps (CCFL), which are said to require much less wattage, consume up to 80 percent less power and last 18 times longer. The Micro-Brite CCFL globes used in the trial are dimmable and flashable as well as being very energy-efficient. Lamps in Micro-Brite’s range (currently in 3-, 5- and 8-watt versions) are rated to last 18,000 to 25,000 hours, which is four times longer than compact fluorescent lamps (CFL) and 18 times longer than incandescent lamps.

Table 3: Comparison of expected spending from a 40 W incandescent versus an 8 W compact fluorescent light (CFL).
Lamp type	40W incandescent	8W CFL
Hours per year	8,760	8,760
Watts per year	350,400	70,080
KWH per year	3,504	700.8
Kilowatt hour rate	0.15c	0.15c
Cost per socket	$52.56	$10.51
Total cost for 18,000 hrs	$108.00	$21.60
Total number of sockets	100	100
Total energy consumption	$10,800.00	$2,160.00
Lamp cost (GLS $1/M$30)	$18.00	$30.00
Labour cost est. $25/h	$75.00	$4.20
Total cost per socket (more than 18,000 hours)	$201.00	$55.80

NSW Energy Savings Scheme (ESS)

When seeking suppliers and installers of lights, ask if they’re Accredited Certificate Providers (ACP) under the NSW Energy Savings Scheme.

Products that are certified under the scheme and provided and installed by an ACP are commonly offered at much lower prices, as they are partly subsidised by the production of Energy Saving Certificates (ESCs or ‘eskeys’). In certain instances – usually when retrofitting halogen lights with LED technologies – the subsidy allowed by the generation of ESCs is more than sufficient to cover the entire cost of the lighting unit, and can therefore result in getting a new lighting retrofit for free.

Consult the links provided at the end of this information sheet for a list of certificate providers accredited under the ESS.

De-lamping

De-lamping can be one of the easiest ways to reduce energy use and, as the name suggests, involves removing unnecessary light fixtures in places where light levels are above what is required.

Before removing any lights, you should conduct a light-level assessment of the candidate premises. This can be done using a lux meter and checking actual levels of illumination against the minimum luminance levels recommended by relevant lighting standards (AS/NZS1680).

Reflectors

Figure 2: Reflectors direct light downward from the fixture.

Green Riverside

As shown in Figure 2, in some cases, a farmer can remove one fluorescent tube from a bank of two without significant sacrifices in light levels by using reflectors. You should also consider wiping/cleaning existing reflectors to ensure light levels are being maintained.

From an occupational health and safety perspective, every business needs to ensure that after any reduction in light output, its site continues meets minimum luminance levels recommended by relevant lighting standards (AS/NZS1680).