"Home made" 150 kW heat pump

[SteinarN]

I constructed a fairly large water/water heat pump in November -05. It heats an assisted living facility of 4,900 m2, that is 52,700 ft2, two ventilation systems of a combined 9 m3/s capacity and 300 m2 heated outside area.

The heating capacity is between 140 to 155 kW dependent of the ground loop temperature and the outlet water temperature. It extracts heat from 19 wells, each 155m deep, 508ft, total 2950m, 9678ft.

The return temperature in the ground loop water/glycol mix is 5C in the autumn at the start of the heating season and drops to -1.5C in the spring. Flow is 10.5 l/s, 2.77 US Gal/s. Dt is 3.5C at full capacity. Heat extracted is 110 to 125 kW.

Outlet water temperature on the warm side is regulated dependent of the ambient temperature, varying between 21C at 20C ambient and 32C at -20C ambient. Warm side flow is roughly 8 l/s.

It is equipped with a liquid refrigerant subcooler connected to the water return from one of the ventilation system heating coils. This cools the liquid refrigerant from between 26 to 36C down to 20 to 21C. This cooling of the liquid/heating of the water yields an additional up to 20 kW heating capacity without affecting the compressor power consumption. The COP is 4.6 to 5.2 dependent of the water temps. This is a very high COP.

The compressor is an eight cylinder Copeland Discus compressor, the 2nd largest. Displacement is 2,060 cm3. Max amps is 152 A at 230 V. 50-75-100% capasity steps. Power consumption under actual running conditions is 31 kW at 100% capasity.

Pictures: http://s684.photobucket.com/albums/v...20heat%20pump/