A versatile way to integrate solar thermal and geothermal heat pumps.
Two thermally based renewable energy technologies that grab many headlines these days are solar water heating and geothermal heat pumps. Both now enjoy the “favored status” of a 30% income tax credit from Uncle Sam, as well as numerous other rebates and credits at the state level.
Solar thermal systems and geothermal heat pump systems are both ways of capturing solar energy. The solar thermal system does it in real time, whereas the geothermal heat pump system, operating from a horizontal earth loop, extracts solar heat driven into the soil several months earlier. This time shift between when the energy is available and when it’s needed allows combinations of solar thermal hardware and geothermal heat pumps to be complementary.
Take a look at the system schematic in Figure 1. It combines both solar thermal and geothermal heat pump subsystems into an overall system for space heating, space cooling and domestic water heating.