This paper provides a brief study of various ground-source heat pump (GSHP) pumping alternatives. The first alternative is subcentral circulator pumping with various size pumping loops followed by constant-volume central pumping and then variable-volume central pumping. This study found that variable-volume central pumping provided higher available differential pumping heads at lower energy demands for the same flow rates than the constant-volume central pumping and the circulator pumping alternatives for all flow rates tested with the exception of flow rates below 22 gpm. Below 22 gpm, the circulator pumping method proved to be the pumping method of choice. This paper also proves that constant-volume pumping is the worst energy consumer at almost every flow demand.

Units: Dual