Abstract: A building-integrated solar energy system is disclosed that comprises an evacuated closed-loop conduit network circulating a working fluid through a solar thermal collector and at least one heat usage device, wherein the effective entirety of the surfaces of the closed-loop conduit network are in contact with the working fluid such that phase change occurs whenever heat energy is added by the solar thermal collector or removed by a heat usage device. The working fluid is adiabatically isolated and contained in a low pressure environment within the closed-loop conduit network. The full surface contact and low-pressure isolation of the working fluid dramatically reduces temperature differentials and energy losses, allowing for highly efficient and cost-effective heat collection and distribution.

Abstract: An energy collector is disclosed. The energy collector contains an absorber and a working fluid. The working fluid is held in a state of two-phase equilibrium to minimize sensible heating and thus heat losses to the environment. The energy collector may be held under a vacuum to further prevent heat losses to the ambient environment. One or more energy collectors may be connected to other energy collectors, end uses, or thermal energy storage.

Abstract: A building-integrated solar energy system that concurrently provides space heating, space cooling, hot water, and electricity to commercial and residential buildings. The solar energy system comprises an evacuated closed-loop conduit network circulating a working fluid through a solar thermal collector and at least one heat usage device, wherein the effective entirety of the surfaces of the closed-loop conduit network are in contact with the working fluid such that phase change occurs whenever heat energy is added by the solar thermal collector or removed by a heat usage device. The solar energy system further comprises an impermeable outer housing enveloping the closed-loop conduit network and forming an evacuated space located between and defined by the outer surface of the closed-loop conduit network and the inner surface of the impermeable housing such that the working fluid is adiabatically isolated.