A 203kW (58 ton) water-loop heat pump system was installed in a 1459 m² (15700 ft²) office building addition in Columbia, Ohio. The new heating, ventilating and air conditioning (HVAC) system is expected to consume 40% less energy than the electric resistance heating system with rooftop air conditioning in the original office building. The 28 water-loop heat pumps are connected to closed vertical ground loops totalling 5944 m (19500 ft) in length. The loops are installed in 65 boreholes each 46 m (150 ft) deep. The new HVAC system is the first commercial water-loop heat pump system in the United States using scroll compressors and variable-speed blowers in horizontally mounted heat pumps. The new technology provides a coefficient of performance (COP) as high as 3.6, as rated by ARI standard 330-90. Describes the design and installation of this new heat pump system and gives the actual performance results for its first six months of operation.

KEYWORDS: water heat pumps, heat pumps, soil heat exchangers, designing, USA, vertical, air conditioning.