Abstract: A heat-exchanging system for an enclosed space having wall-forming members, pipes provided on said members, and being adapted for discharging water for flow along the surfaces of the same, a source of water, a pump connecting said source and said pipes, ducts for returning water to said source, and a temperature sensor controlling the operation of said pump whereby said members serve as a heat exchanger for both heating and cooling purposes in response to predetermined temperatures.

Abstract: A passive-type solar device comprising a transparent plate disposed for exposure to sunlight, a reflecting film curtain provided in alignment with said transparent plate and adapted for covering and uncovering movement with respect thereto, and a heat insulating, sunlight transmissible, board provided in alignment with said reflecting film curtain, said board comprising at least first and second sections of predetermined thickness in spaced apart relationship with an intervening air layer, each of said sections being constituted of a honeycomb material member sandwiched between transparent plates.