Abstract: Various techniques are disclosed for improving airtight two-phase heat-transfer systems employing a fluid to transfer heat from a heat source to a heat sink while circulating around a fluid circuit, the maximum temperature of the heat sink not exceeding the maximum temperature of the heat source. The properties of those improved systems include (a) maintaining, while the systems are inactive, their internal pressure at a pressure above the saturated-vapor pressure of their heat-transfer fluid; and (b) cooling their internal evaporator surfaces with liquid jets. FIG. 43 illustrates the particular case where a heat-transfer system of the invention is used to cool a piston engine (500) by rejecting, with a condenser (508), heat to the ambient air; and where the system includes a heat-transfer fluid pump (10) and means (401-407) for achieving the former property.

Abstract: Various techniques are disclosed for improving systems that include an evacuated, and in essence hermetically-sealed, fluid circuit containing a heat-transfer fluid which--while circulating, usually with the assistance of a pump, around the fluid circuit--absorbs heat, primarily by evaporation, from a heat source and releases the absorbed heat, primarily by condensation, to a heat sink; the maximum temperature of the heat sink being, at a given instant in time, lower than the maximum temperature of the heat source at that instant in time.The various techniques disclosed always furnish the fluid circuit with a property named `self-regulation`; and, where applicable, with one or more properties named `overpressure protection`, `freeze protection`, `heat-absorption control`, `heat-release control`, and `heat-source control`.

Abstract: Various control methods and means are disclosed for varying the temperature of vaporization of a solar-powered system so that the instantaneous power delivered by the heat engine of this system, or by a device driven by this engine, is a maximum for given conditions external to the power system, or to the power system and the driven device, respectively, while ensuring that dry saturated vapor, or vapor with a preselected amount of superheat is supplied to the heat engine.The power system uses a Rankine power cycle whose working fluid is either vaporized in the absorber of a solar collector, or in a heat exchanger by a separate fluid which absorbs heat by flowing through the solar collector absorber.Also, various methods and means are disclosed for controlling the foregoing separate heat-transfer fluid so that it absorbs sensible and latent heat in the absorber of the solar collector in essentially the same ratio as the power-cycle working fluid absorbs sensible and latent heat from this heat-transfer fluid.

Abstract: Various systems are disclosed for absorbing radiant heat, especially solar heat, by evaporating a refrigerant, and for releasing the heat thus absorbed to a medium to be heated, by condensing the evaporated portion of the refrigerant. The refrigerant fluid loop includes (1) an evaporator, or solar collector, including passageways where at least a portion of the refrigerant is vaporized, (2) a separator which may be a part of or a separate component from the evaporator, that divides the vapor portion and the liquid portion of the refrigerant exiting the evaporator passageways, (3) a condenser for condensing the vapor portion of the refrigerant and transferring the latent heat released to a medium to be heated, and (4) a condensate pump to return the liquid refrigerant from the separator and condenser to the evaporator. Systems are also disclosed for returning the liquid refrigerant to the evaporator by gravity thus eliminating the need for a condensate pump.

Abstract: A combined heating and cooling system includes a solar collector and evaporator for absorbing heat from solar radiation and/or the ambient air and for using the absorbed heat to evaporate a binary-phase, liquid-vapor working fluid. In the heating mode, whenever the temperature of the working fluid inside the evaporator of the solar collector is sufficiently higher than that of the medium to be heated, the working fluid follows a cycle similar to the Rankine cycle in which the heat engine is eliminated. Whenever the temperature of the working fluid inside the evaporator is no longer high enough for heat to be transferred unassisted to the medium to be heated, the working fluid is made to follow a heat-pump cycle. Finally, whenever the temperature of the working fluid in the evaporator falls below the temperature of the surrounding air, the evaporator is exposed to the ambient air and the system runs as an air-source heat pump.