The disclosed technology includes an on-demand water heater which uses an electric heat source to heat the water. The on-demand water heater can have a low fluid capacity heating chamber which has an inlet and an outlet, an electric heat source for heating the water, and a controller to control the electric heat source and maintain the temperature of the water at a predetermined temperature setting. The on-demand water heater can be powered by a direct current power source. The on-demand water heater can also utilize a solar thermal system to provide additional heat to the water.

A heat transfer system includes a conduit having open first and second ends, first and second thermal exchange segments disposed in-between and in fluid communication with the ends, and a means for adding fluid to the first end. The first thermal exchange segment is disposed underneath and in thermal communication with the ground, a body of water, or other location with a different temperature. The first and second ends are arranged above all other section of conduit and relative to one another so that they are communicating vessels and a change in fluid level in one changes the fluid level in the other. The means for adding fluid to the first end of the conduit causes fluid to flow freely from the first end to the second end and fluid level to rise in the second overcoming any hydrostatic pressure in the system without a pump disposed along the conduit.

A heat transfer system includes a conduit having open first and second ends, first and second thermal exchange segments disposed in-between and in fluid communication with the ends, and a means for adding fluid to the first end. The first thermal exchange segment is disposed underneath and in thermal communication with the ground, a body of water, or other location with a different temperature. The first and second ends are arranged above all other section of conduit and relative to one another so that they are communicating vessels and a change in fluid level in one changes the fluid level in the other. The means for adding fluid to the first end of the conduit causes fluid to flow freely from the first end to the second end and fluid level to rise in the second overcoming any hydrostatic pressure in the system without a pump disposed along the conduit.

Disclosed is a device with a heat exchanger having a first flow through which a first gaseous heat transfer medium passes and a second flow through which a second gaseous heat transfer medium passes. Upstream of the first flow, there is a combustion chamber, which optionally extends into the first flow. Two feed lines are attached to the first flow, of which the first feed line is connected to a thermal solar installation and the second feed line is connected to a source for a combustible gas-air mixture or for a non-combustible gas, in particular an oxygen-containing gas, such as air.

Disclosed is a device with a heat exchanger having a first flow through which a first gaseous heat transfer medium passes and a second flow through which a second gaseous heat transfer medium passes. Upstream of the first flow, there is a combustion chamber, which optionally extends into the first flow. Two feed lines are attached to the first flow, of which the first feed line is connected to a thermal solar installation and the second feed line is connected to a source for a combustible gas-air mixture or for a non-combustible gas, in particular an oxygen-containing gas, such as air.

Apparatuses and methods for using direct solar radiation. The apparatus may include a housing defining a window configured to transmit solar radiation and a secondary radiation source for transmitting a second radiation in response to the solar radiation via a non-transitory computer-readable medium having computer-readable instructions stored thereon and configured to be executed by a processor to measure the solar radiation and actuate the secondary radiation source.

Apparatuses and methods for using direct solar radiation. The apparatus may include a housing defining a window configured to transmit solar radiation and a secondary radiation source for transmitting a second radiation in response to the solar radiation via a non-transitory computer-readable medium having computer-readable instructions stored thereon and configured to be executed by a processor to measure the solar radiation and actuate the secondary radiation source.

Heat exchange system on a roof of a building, with an exchange volume comprising a substrate that is partly saturated by water and covered by a vegetated surface that enhances condensation and evapotranspiration and having a heat diffusion device comprising a circulation pump and a collection network for thermal exchanges with the exchange volume.

A heating and cooling system powered by renewable energy and assisted with geothermal energy includes a solar cycling unit, a supercritical carbon dioxide (S—CO.sub.2) unit, and a refrigerant cycling unit. Solar energy obtained at the solar cycling unit may be used to power the S—CO.sub.2 cycling unit. To do so, the solar cycling unit utilizes a solar collector, a thermal energy storage, and a heat exchanger along with a first working fluid which is preferably molten salt or Therminol. Next, the energy generated at the S—CO.sub.2 cycling unit, which preferably circulates S—CO.sub.2 as a second working fluid, may be used to operate the refrigerant cycling unit. In the refrigerant cycling unit, Tetrafluroethene is preferably used as the third working fluid to produce required cooling effects. Additionally, geothermal heat exchangers may be integrated into the system for use during varying weather conditions.

A heating and cooling system powered by renewable energy and assisted with geothermal energy includes a solar cycling unit, a supercritical carbon dioxide (S—CO.sub.2) unit, and a refrigerant cycling unit. Solar energy obtained at the solar cycling unit may be used to power the S—CO.sub.2 cycling unit. To do so, the solar cycling unit utilizes a solar collector, a thermal energy storage, and a heat exchanger along with a first working fluid which is preferably molten salt or Therminol. Next, the energy generated at the S—CO.sub.2 cycling unit, which preferably circulates S—CO.sub.2 as a second working fluid, may be used to operate the refrigerant cycling unit. In the refrigerant cycling unit, Tetrafluroethene is preferably used as the third working fluid to produce required cooling effects. Additionally, geothermal heat exchangers may be integrated into the system for use during varying weather conditions.