RainMaker – Simple and Effective Cooling System

By Big Dutchman. RainMaker is a pad cooling system developed by Big Dutchman for poultry houses particularly in areas that have hot, dry summers.
calendar icon 21 December 2007
clock icon 5 minute read

It features an innovative frame system and has minimum installation requirements, designed for simple supervision and maintenance.

Because the cooling system works on the basis of evaporation and is, therefore, mainly used in climate regions with hot and dry summers, the higher the temperatures and the lower the relative humidity, the higher the resulting cooling effect will be.

The pads that are used consist of a special cellulose material with a large specific surface to ensure a high cooling performance. A chemical impregnation protects the pads from atmospheric influence. Alternatively, there are also plastic pads available which are built for a longer service life.

RainMaker with plastic pads Double RainMaker for high cage houses

Frame system with top profile and pad retainer

A core part of the new frame system is the top profile - the complete upper part of the frame, made from one piece.

It is designed as an open system, which means the water supply is always visible and there is no closed space available to serve as a nesting place for rodents, or other pests.

The system has a perforated pipe, which is integrated into the top profile and distributes water down the pads. It is visible to the operator, so that any dirt and obstructions in the holes can be spotted immediately.

A special deflector spreads the water evenly along the pads to ensure an ideal wetting of the pads.

The deflector is connected to the top profile by a plastic hinge, which can easily be folded up for maintenance, with no tools or any parts to remove. The top profile is simply snapped into the pre-mounted wall brackets to allow for simple assembly and the pads can be easily released so that they can also easily be replaced.

Top profile with perforated pipe and
deflector for an even distribution of
water along the pads
Practical snap retainers allow for a
simple and quick replacement of the

Water reservoir, centrifugal pump and supply unit with float valve

Excess water is collected at the bottom part of the frame - the water reservoir - and is then returned to the cycle. The special profile is designed to provide more stability. The reservoir is designed to be large enough so that no additional water tank is needed. The covering, which supports the pads, is simply mounted onto the water reservoir and it can easily be removed for maintenance. The special perforation ensures a back flow of excess water and, at the same time, prevents rodents getting in.

When RainMaker is in operation, some water evaporates so the mineral content in the circulating water increases. To prevent deposits on the pads, a part of the water has to be continuously drained off. The amount of water that is bled off depends on the water quality and on the amount of evaporated water. It is usually 10 per cent of the water throughput , where the water quality is good.

As an optional feature the system can have an extended centre coupler, which allows easy maintenance because it provides easier access to the float valve.

Water resevoir for up to 48 litres
per running metre water capacity
Centifugal pump including filter and
bleed off

Mode of operation

The pads - made of cellulose or plastic - are soaked from above and thanks to negative pressure ventilation inside the poultry house, the warm outside air is sucked into the house through the moist pads. The air takes up humidity and cools down the atmosphere. Excess water is collected in the water reservoir and returned to the cycle.

The water it is pumped up to the pads by the centrifugal pump.

Combined with tunnel ventilation, Big Dutchman says it is possible to achieve a very efficient cooling effect, especially in large house compartments.

Corridor for higher air entrance speed

If RainMaker is to be used on hot summer days only, or a second ventilation system is available for the cold season (Combi-Tunnel-Ventilation), Big Dutchman recommends extending the building with a corridor or "dog-house".

This way, it says, it is possible to keep the air inlets in the wall of the building much smaller.

This has the advantages:

  • that the necessary air speed can be precisely adjusted, giving a better distribution of air in the house;
  • insulation is cheaper for the winter time;
  • the house can be made airtight by means of a roller curtain in the dog-house where it is protected from dust and other environmental effects;
  • it provides good protection against wind, light and rain and;
  • service and maintenance works may be carried out regardless of whether the house is occupied or not, no water enters the house.
Corridor for more precise air supply Tunnel inlet with roller curtain

Technical specifications

The frame system allows for pads that are 10cm (4 ") and 15cm (6 ") thick. The two-piece side parts are made from stainless steel and can be easily adjusted for pad heights of 1.20 to 2.0 metres.

The water reservoir is available in two sizes: 3 metres or 10 feet and there are two circular pumps including filters for pads of up to 12 metes long (code no. 62-00-3522) and for pads of from 12 metres to a maximum of 30 metres (code no. 62-00-3523).

December 2007
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