All conventional sources of light produce heat as well as light. While some lights sources like the incandescent filament lamp are quite inefficient, producing huge amounts of heat, others like the sodium vapor lamp are somewhat more efficient and run comparatively ?cool?. In applications like hydroponics this heat produced in the lamp can have several deleterious effects on the plants in an indoor grow room. It is imperative in such applications that the heat generated in the lamp is dissipated effectively and efficiently so that plant growth is not adversely affected.



Perhaps, the best approach is to deal with the problem at the source. Water cooled lighting attempts to address the problem by conducting the heat away from the source, using a water circulating system. There are several such systems to choose from, which allows growers a degree of flexibility in selecting the system best suited to their needs and preference.

Water cooled lighting is typically available in the higher wattage range with 400W and 600 W high pressure sodium (HPS) or metal halide (MH) lamps along with accessories such as reflector, remote ballast, contactor, relay timer etc. The basic lighting system is the same as the one used commonly, the special feature being the replaceable lamp which is encased within two tubes. Water flows thru the tubes that allow for maximum heat transfer leaving the casing cold to the touch. This is ideally suited for mounting the lights in close proximity to plants, which ensures availability of more light for plant growth. This also eliminates the problem of plants burning due to their proximity to the intense heat of the high wattage lights.

Cooling Systems

The cold water is taken from a reservoir; for best results large reservoirs are preferable. Large reservoirs enable greater heat dissipation which allows several lamps to share a common reservoir. The water may be obtained from any clean source, like the local municipally water supply as this will reduce maintenance, though other sources may also suffice. Growers can choose from a number of cooling systems. These include:

Run to Waste

This system is cheap, easy to set up and requires minimal hardware support. Best suited for growers with just a few lights it basically comprises a hose connected to a tap at one end. At the other end, the hose is connected to the first of the lights that are arranged serially. The water finally exits through the last light and is vented to waste. This system will require a good quality water supply such as the municipal supply.

Recirculation System

This system saves on water costs and uses a heat exchanger to cool the heated water thus saving on the consumption of water and electricity. It comprises a reservoir, filter, hose and heat exchanger and pump. Water is pumped from the reservoir through the filter, passes through the lights and is then cooled in the heat exchanger prior to flowing back to the reservoir.

This system is recommended by many manufactures of water-cooled-lights.

System for Venting Heat to Lakes, Streams etc.

This system offers an easy way of getting rid of the heat produced in the lights for people who live near large bodies of water like lakes, streams etc. The system involves stringing several hundred feet of garden hose from the pump in the reservoir to the lake. From the lake it is connected back to the house to the inlet to the lights. The water is pumped from the reservoir, through the hose in the lake where it gives off its heat before re-entering the lights.

The systems described above comprise only a few of the cooling options for use with water cooled lights available to growers today. Several advanced systems incorporating the basic features of the above cooling systems can be built to optimize lighting performance and enhance grow-room productivity.

Water cooled lighting systems have been around since a decade; growers have reported all-round benefits of incorporating such systems in their grow rooms. The following benefits reported by growers will perhaps help you in making informed decisions about water cooled lighting your grow room -

Enhanced grow tent productivity

Better control over pests

Reduction in installation size

All weather operation through out the year

Modular design for rapid, easy setup and expansion.

Easy and fast dismantling and disassembly