An apparatus includes first and second tanks each configured to receive and store a refrigerant under pressure. The apparatus also includes at least one generator configured to generate electrical power based on a flow of the refrigerant between the tanks. The apparatus further includes a collector configured to transfer solar thermal energy to one of the tanks to heat the refrigerant in that tank and/or radiate thermal energy from one of the tanks into an ambient environment to cool the refrigerant in that tank. In addition, the apparatus could include first and second insulated water jackets each configured to receive and retain water, where the first tank is located within the first insulated water jacket and the second tank is located within the second insulated water jacket.

An apparatus includes first and second tanks each configured to receive and store a refrigerant under pressure. The apparatus also includes at least one generator configured to generate electrical power based on a flow of the refrigerant between the tanks. The apparatus further includes a collector configured to transfer solar thermal energy to one of the tanks to heat the refrigerant in that tank and/or radiate thermal energy from one of the tanks into an ambient environment to cool the refrigerant in that tank. In addition, the apparatus could include first and second insulated water jackets each configured to receive and retain water, where the first tank is located within the first insulated water jacket and the second tank is located within the second insulated water jacket.

In one general aspect, a microelectronics cooling device can include a microchannel heat exchanger within an enclosure that houses the device at a heat absorbing end and another heat exchanger which is optionally also a microchannel heat exchanger at a heat sink end outside the enclosure. One or more pipes flowably connect the two ends for transporting liquid working fluid to the heat absorber and vaporized working fluid to the heat sink. The heat pipes may also be used to transfer heat outside a room that contains the electronic devices.

In one general aspect, a microelectronics cooling device can include a microchannel heat exchanger within an enclosure that houses the device at a heat absorbing end and another heat exchanger which is optionally also a microchannel heat exchanger at a heat sink end outside the enclosure. One or more pipes flowably connect the two ends for transporting liquid working fluid to the heat absorber and vaporized working fluid to the heat sink. The heat pipes may also be used to transfer heat outside a room that contains the electronic devices.

There is herein described energy storage systems. More particularly, there is herein described thermal energy storage systems and use of energy storable material such as phase change material in the provision of heating and/or cooling systems in, for example, domestic dwellings.

There is herein described energy storage systems. More particularly, there is herein described thermal energy storage systems and use of energy storable material such as phase change material in the provision of heating and/or cooling systems in, for example, domestic dwellings.

A silica aerogel having a mean pore size less than 5 nm with a standard deviation of 3 nm. The silica aerogel may have greater than 95% solar-weighted transmittance at a thickness of 8 mm for wavelengths in the range of 250 nm to 2500 nm, and a 400 C. black-body weighted specific extinction coefficient of greater than 8 m.sup.2/kg for wavelengths of 1.5 m to 15 m. Silica aerogel synthesis methods are described. A solar thermal aerogel receiver (STAR) may include an opaque frame defining an opening, an aerogel layer disposed in the opaque frame, with at least a portion of the aerogel layer being proximate the opening, and a heat transfer fluid pipe in thermal contact with and proximate the aerogel layer. A concentrating solar energy system may include a STAR and at least one reflector to direct sunlight to an opening in the STAR.

A silica aerogel having a mean pore size less than 5 nm with a standard deviation of 3 nm. The silica aerogel may have greater than 95% solar-weighted transmittance at a thickness of 8 mm for wavelengths in the range of 250 nm to 2500 nm, and a 400 C. black-body weighted specific extinction coefficient of greater than 8 m.sup.2/kg for wavelengths of 1.5 m to 15 m. Silica aerogel synthesis methods are described. A solar thermal aerogel receiver (STAR) may include an opaque frame defining an opening, an aerogel layer disposed in the opaque frame, with at least a portion of the aerogel layer being proximate the opening, and a heat transfer fluid pipe in thermal contact with and proximate the aerogel layer. A concentrating solar energy system may include a STAR and at least one reflector to direct sunlight to an opening in the STAR.

A cogeneration system to generate thermal energy in form of hot water, using the system's solar collector directly as an evaporator and a heat exchanger integrated in a thermal tank used as a condenser. A variable capacity expander (turbine) is used and the organic working fluid selection is specific for this application. Thus is provided a technological alternative for the production of electricity and thermal energy using a renewable energy source.

A building envelope, in particular a wall, a floor, or a roof of a building with at least two shells spaced some distance apart from one another, which encloses an intermediate space, said space being essentially empty with the exception of weight-bearing and/or construction-engineering elements or being filled at least in sections with porous, open-celled material and sealed from the interior and exterior of the building, wherein controllable sealing means are provided for sealing the intermediate space from the interior and exterior and optionally separated building envelope sections from one other.