A refrigeration and/or heat transfer device includes a heating section and cooling section, a release member, and a one-way check valve affixed together in a continuous loop so working fluid may flow in one direction therein. The heating section absorbs heat and transfers such heat to the working fluid, thereby heating, expanding and increasing pressure upon the working fluid therein. The pressurized working fluid is released in a regulated manner from the heating section to the cooling section, thereby carrying the heat away. The released working fluid cools and transfers its heat to the surroundings within the cooling section. As released working fluid enters the cooling section, such fluid displaces already cooled working fluid, pushing such fluid through the one-way check valve back into the heating section to absorb heat. The working fluid may undergo a phase change or remain in a single phase throughout to enhance heat transfer.

A solar thermophotovoltaic system has a heat exchanger containing a heat exchange fluid, and a thin-film integrated spectrally-selective plasmonic absorber emitter (ISSAE) in direct contact with an outer surface of the heat exchanger, the ISSAE including an ultra-thin non-shiny metal layer that is strongly absorbing in a solar spectral range and strongly reflective in an infrared spectral range. The metal layer has an inner surface in direct contact with an outer surface of the heat exchanger. A photovoltaic cell support structure with an inner surface in a concentric configuration partially surrounds the ISSAE; and an airgap separates the support structure and the outer surface of the metal layer. Photovoltaic cells are arranged on a portion of the inner surface of the support structure to receive emissions from the ISSAE, and a solar energy collector/concentrator allows solar radiation to impinge a portion of the metal layer.

A solar thermophotovoltaic system has a heat exchanger containing a heat exchange fluid, and a thin-film integrated spectrally-selective plasmonic absorber emitter (ISSAE) in direct contact with an outer surface of the heat exchanger, the ISSAE including an ultra-thin non-shiny metal layer that is strongly absorbing in a solar spectral range and strongly reflective in an infrared spectral range. The metal layer has an inner surface in direct contact with an outer surface of the heat exchanger. A photovoltaic cell support structure with an inner surface in a concentric configuration partially surrounds the ISSAE; and an airgap separates the support structure and the outer surface of the metal layer. Photovoltaic cells are arranged on a portion of the inner surface of the support structure to receive emissions from the ISSAE, and a solar energy collector/concentrator allows solar radiation to impinge a portion of the metal layer.

Techniques for hybrid solar thermal and photovoltaic energy collection are provided. In one aspect, a photovoltaic concentrating thermal collector (PVCTC) includes: a thermal absorber collector; and bent solar panels forming a parabolic shaped trough reflector partially surrounding the thermal absorber collector so as to reflect incident light onto the thermal absorber collector. A PVCTC system including an array of PVCTC units and a method for hybrid electrical and thermal energy production are also provided.

Techniques for hybrid solar thermal and photovoltaic energy collection are provided. In one aspect, a photovoltaic concentrating thermal collector (PVCTC) includes: a thermal absorber collector; and bent solar panels forming a parabolic shaped trough reflector partially surrounding the thermal absorber collector so as to reflect incident light onto the thermal absorber collector. A PVCTC system including an array of PVCTC units and a method for hybrid electrical and thermal energy production are also provided.

A curved surface absorber type solar fluid heater having radially spaced curved surfaces, preferably hemispherical and closed at bottom periphery, defining a closed chamber termed as collector which receives a fluid to be heated. The curved surface absorber type solar fluid heater encompasses two radially spaced transparent curved surfaces preferably hemispherical, closed at bottom periphery, placed over collector termed as a glazing, and an insulated hemispherical hot fluid tank, placed within the cavity of inner curved surface of the collector and bottom insulation. A plurality of plumbing connections is made between the collector and the hot fluid tank with arrangement of non-return valves to prevent backflow of fluid from hot fluid tank towards the collector. An air vent is located at the highest position of the collector. A drain plug is located at a lowest position on the collector.

A curved surface absorber type solar fluid heater having radially spaced curved surfaces, preferably hemispherical and closed at bottom periphery, defining a closed chamber termed as collector which receives a fluid to be heated. The curved surface absorber type solar fluid heater encompasses two radially spaced transparent curved surfaces preferably hemispherical, closed at bottom periphery, placed over collector termed as a glazing, and an insulated hemispherical hot fluid tank, placed within the cavity of inner curved surface of the collector and bottom insulation. A plurality of plumbing connections is made between the collector and the hot fluid tank with arrangement of non-return valves to prevent backflow of fluid from hot fluid tank towards the collector. An air vent is located at the highest position of the collector. A drain plug is located at a lowest position on the collector.

Systems and methods for a thermosyphonic water heating system for a storage tank. A DC heat pump receives power from a DC power source and heats water via a heat exchanger using a thermosyphonic piping system. A passive back-flushing having a cold water inlet pipe connected to the hot water return pipe draws cold water into the storage tank through the heat exchanger. A vertical array of temperature sensors distributed throughout the storage tank monitor temperature of stored water at multiple heights and a communication unit communicates monitored data to an external control device.

Systems and methods for a thermosyphonic water heating system for a storage tank. A DC heat pump receives power from a DC power source and heats water via a heat exchanger using a thermosyphonic piping system. A passive back-flushing having a cold water inlet pipe connected to the hot water return pipe draws cold water into the storage tank through the heat exchanger. A vertical array of temperature sensors distributed throughout the storage tank monitor temperature of stored water at multiple heights and a communication unit communicates monitored data to an external control device.

A hydride heat engine produces electricity from a heat source, such as a solar heater. A plurality of metal hydride reservoirs are heated by the heating device and a working fluid comprises hydrogen is incrementally move from one metal hydride reservoir to a success metal hydride reservoir. The working fluid is passed, at a high pressure, from the last of the plurality of metal hydride reservoirs to an electro-chemical-expander. The electro-chemical-expander has an anode, a cathode, and an ionomer therebetween. The hydrogen is passed from the anode at high pressure to the cathode at lower pressure and electricity is generated. The solar heater may be a solar water heater and the hot water may heat the metal hydride reservoirs to move the hydrogen. The working fluid may move in a closed loop.