Geothermal heat pumps achieve high efficiency by extracting or
rejecting heat to the ground surrounding a building through
either horizontal or vertical heat exchangers. Their operation
is not adversely affected by weather changes as electric heat
pumps are on very cold winter days or heat pumps and air
conditioners are on hot summer days. Projects were undertaken to
develop new or improve existing computer models for simulating
ground coil performance, to demonstrate and monitor ground coil
installations, to develop and test water source heat pumps, and
to document ground-water resources in the U.S. for ground-water
heat pumps.