Abstract: A heat pump system selectively operable in cooling and heating modes of operation and having a combustion prime mover which produces refrigerant vapor compression and which produces combustion heat in greater amounts than usable energy for motive power, provided with a first heat exchanger that evaporates compressed refrigerant in the system heating mode of operation and with a first radiator means which transfers excess prime mover heat to a working fluid, and with a working fluid distribution means selectively operable to proportionately flow the heated working fluid to the first radiator in convective heat exchange relations to the first heat exchanger means, in the system heating mode of operation, to provide defrost capabilities and especially to improve heat pumping capacity at low ambient temperatures.

Abstract: A method, apparatus and system is provided for controlling the rate of insolation transmission through the roof of a building, such as a greenhouse. The roof is provided with translucent panels through which liquid containing opaquing material passes. Control is effected by varying the amount of opaquing material passing through the panels, according to preselected optimum fulfillment of the combined heating, cooling and insolation needs of the building under varying atmospheric conditions.