Heat-activated multiphase fluid-operated pump for geothermal temperature control of structures

Abstract

A heat-activated fluid pump heats and cools a building. For cooling, an evaporator, coupled to a solar heater or comprising multi-pane windows with solar radiation-absorbent areas thermally coupled to a fluid cavity, converts a working fluid into a vapor. A pressure control valve allows vaporized working fluid into a liquid-piston chamber whenever a target pressure in the evaporator is exceeded. The working fluid expands, displacing liquid from the liquid-piston chamber in a pump stage where it enters a condenser situated in a vertical hole or covered horizontal trench in the ground. Ground-temperature pumped fluid returning to the liquid-piston chamber in a suction stage passes along the way through coils in rooms of the building. Check valves allow replenishment of the evaporator with return working fluid and direct flow of pumped fluid into and out of the liquid-piston chamber. For heating, the evaporator is in the ground.