Water to Water Heat Pumps

Another option for Commercial/Industrial Heat Pump water heaters is the Water to Water - or hydro sourced Heat Pump.   Water source heat pumps (WSHP) are specialized types of heat pumps that can also be used as reverse cycle or multi function units that use water as a heat source when in the heating mode and as a heat sink in the cooling mode. In the Water to Water HeatPump, heat is absorbed or rejected in a fluid medium rather than from the ambient air. Water loop heat pumps (WLHP) use a circulating water loop which could be from a chiller/cooling tower system as the primary heat source for the liquid refrigerant causing it to vaporize before moving it to where it is upgraded by an electrically-driven compressor and is then subsequently delivered at a useful super heated temperature for heating potable water via a suitable heat exchanger.

A typical schematic of a multi function Water sourced Heat Pump shown above indicates how in some cases a single Water to Water Heat Pump Unit can be used to provide hot water, air conditioning, as well as under floor heating if required.   In the schematic layout above the primary heat source can be provided by any medium (ground, lake, sea water or hotel cooling tower circuits) where heat energy can be captured (transferred) in the primary evaporator in the Heat Pump Unit.   These types of Heat Pumps can also be used very effectively for just the hot water output function depending upon the project requirements and still have the capability of delivering a very high Coefficient of Performance (COP) outcome of over 370% more than the actual energy consumed.   However, when used as a multi function unit for example, delivering hot water and air conditioning in an ambient temperature environment of around 24ºC the combined COP’s for both functions can be as high as 700% more than the energy consumed for the operation of the system.

By Mel Peatey.