Aqua Heat Pumps
Heat pumps work by circulating a working fluid, or refrigerant, which vaporizes at a low temperature (in the evaporator), producing additional energy in the process. A compressor further concentrates the warmed vapor, raising it to a temperature where it can be circulated through an air handler and used for heating. When the cycle reverses, heat is pumped from indoors to out, as with standard air conditioners. Traditionally, heat pumps have been sized to cooling loads and used where outdoor temperatures rarely fall below freezing.
As outdoor temperatures drop, there is less heat available for efficient extraction by the evaporator, and supplemental heat may need to be provided by electric resistance strips. To protect the evaporator from freeze damage, it must occasionally run in a defrost cycle where the flow of refrigerant is reversed, so that heat from the interior of the house will melt accumulated ice deposits in the outdoor coil. This results in uncomfortably cold air being circulated throughout the home during the cycle, a common source of frustration and complaint among heat pump owners.
The Reverse Cycle Chiller, produced by Aqua Products Company, Inc. uses a highly efficient heat exchanger to transfer energy to a water line, achieving temperatures up to 120 degrees in the heating mode, and down to 50 degrees in cooling mode. The water line can then supply a central air handler, a radiant floor heating system or multiple zoned air handlers. This configuration allows the system to be sized for heating loads rather than typically smaller cooling loads.
On its return trip towards the evaporator, the water replenishes a super-insulated tank that serves as a "thermal flywheel," replacing resistance strips as the auxiliary heat source, and supplying heat for the defrost cycle. The system is said to supply a more consistent, comfortable level of heating, that operates efficiently, even at temperatures below 0 degrees Fahrenheit.
