Water Source Air Conditioning & Heat Pump
Water source air conditioning was very popular years ago for cooling homes until the cost of water usage was compounded by added sewer taxation. A water cooled A/C would have the condensing unit with the compressor installed near the furnace or air handler and use domestic water to cool the freon, in contrast to an air cooled unit with the condenser outside. No condenser fan motor is required with a water cooled unit so there is a saving on electricity and because the unit is indoors, it can be used in the middle of winter when air cooled units cannot be used. This made water cooled units very useful for commercial applications where there was a need for year round cooling (eg. computer rooms). Water source heat pumps were also developed for residential and commercial applications and in most cases were able to recycle the water through a boiler and cooling tower system where no water was wasted. The water source heat pumps have become the new “Green Energy” machine for new condominiums that provide each owner the flexibility of heating or cooling when they want it rather than the old method of a central chiller and boiler that was an either / or system for the entire building. This also made each owner responsible for their own maintenance and service with the added reliability of each condo having their own system for their suite.
There are many water cooled A/C’s still in use in some homes and the waste water from the condenser is able to be diverted from the drain to water lawns, wash the car or even heat a swimming pool. Unfortunately the sewer tax still applies regardless of whether the water is recycled for other uses.
All water cooled A/C’s and Heat Pumps are protected against interruptions to the flow of water. Should the water be shut off to a unit while it is operating the refrigerant pressures quickly soar to extreme levels. Before any damage can occur to the unit compressor a pressure switch turns the unit off. This switch will have to be manually reset before the cooling system will operate. The operating manual for the unit will direct you to the location of the high pressure switch reset button. The water flow has to be restored before resetting the switch. Modern heat pump units will also shut off automatically and most can be reset by turning the power supply to the unit off and back on or by switching the thermostat from cool or heat to “OFF” then back to the desired mode of operation.
A rough idea of the amount of water that a water cooled A/C will use, while running is 1 ½ gallons of water per minute per ton. This formulae would illustrate the consumption to be 4 ½ gallons of water in one minute for a three ton unit or approximately 22 liters per minute. The units do not use any water if the A/C or Heat pump is not operating.
The older water cooled units that used the freon, R-22 would discharge water at the above rate of flow per ton at a temperature of exactly 110 degrees F. if the unit was properly set up. This temperature made it wonderful for heating swimming pools, but inconsistent for washing the car. The only problem with pool heating was that the A/C does not run for many hours in the spring and fall when heat is required in the pool and in the heat of the summer can actually overheat the pool.
There is less wear and tear on the compressor of any water source unit as the system is always operating under constant temperature conditions whereas an air cooled condenser could be running in temperatures from 55F to 110F. There are no efficiency losses due to ambient temperatures with water cooled units.