A water heater is provided having an insulated tank having a water inlet and a water outlet, and further defining an interior volume to contain a quantity of water. A primary heating arrangement applies heat energy to the water so as to heat the water. In addition, the primary heating arrangement is configured to maintain the water during standby periods between upper and lower set point temperatures. A supplemental heating arrangement is operative to supply additional heat energy to the water in order to lessen energy usage by the primary heating arrangement during the standby periods. In accordance with a preferred embodiment, the supplemental heating arrangement includes at least one photovoltaic panel and a supplemental heating element. Control electronics are operatively interposed between the at least one photovoltaic panel and the supplemental heating element.

A water heater control system includes: a photovoltaic power generator interconnected with a commercial power supply, an electrical load circuit including a storage-type electric water heater using power from the commercial power supply and generated power of the photovoltaic power generator to perform a water heating operation of heating low temperature water to high temperature water and storing the high temperature water, and a HEMS controller limiting a water heating operation of the storage-type electric water heater by stopping or suppressing the water heating operation of the storage-type electric water heater when a power fee data for purchased power supplied to the electrical load circuit from the commercial power supply exceeds a standard monetary amount.

The integrated solar absorption heat pump system includes an absorption heat pump assembly (AHPA) having a generator, a condenser in fluid communication with the generator, an evaporator/absorber in fluid communication with the condenser and the generator, and a heat exchanger in communicating relation with the evaporator/absorber; a solar collector in fluid communication with the generator of the AHPA; a photovoltaic thermal collector in communicating relation with the evaporator/absorber of the AHPA; a plurality of pumps configured for pumping a fluid throughout the system to provide the desired heating or cooling; a power storage source, e.g., a solar battery, in communicating relation with the photovoltaic thermal collector; and a coil unit in communicating relation to the evaporator/absorber for receiving an air-stream. The absorption heat pump assembly can include an absorber and a solution heat exchanger.

The invention relates to a system for producing hot water, comprising a hot water reservoir, a first and a second resistance heating rod for heating the water in the hot water reservoir, a reservoir temperature sensor, and a control unit, by means of which the first resistance heating rod can be connected to a network alternating voltage source, wherein the system comprises a photovoltaic device for producing a direct voltage and the photovoltaic device can be connected to the second resistance heating rod by means of the control unit or a further control unit.

An energy generating system for generating thermal energy and electrical energy for a premises. The system includes an engine that drives an AC power generator to supply supplemental or standby power to the premises. The thermal energy given off by the engine is also coupled to the premises to provide heat thereto. A processor controls the various parameters of both the energy generating system and the premises to coordinate the proper heating and cooling thereof.

An apparatus for recovering heat in an ablutionary or plumbing system includes first and second pipes for carrying fluids at different temperatures. A first heat transfer element is configured to be thermally coupled to the first pipe and a second heat transfer element configured to be thermally coupled to the second pipe, with each having an elongate portion extending in a direction away from the associated pipe. The elongate portions of the first and second heat transfer elements at least partially overlap. A thermoelectric device is provided that includes one or more thermoelectric elements located between the elongate portions, the thermoelectric element(s) being in thermal communication with the elongate portion of the first heat transfer element and the elongate portion of the second heat transfer element and being arranged to generate electricity from a temperature differential between the elongate portions of the first and second heat transfer elements.

An apparatus for recovering heat in an ablutionary or plumbing system includes first and second pipes for carrying fluids at different temperatures. A first heat transfer element is configured to be thermally coupled to the first pipe and a second heat transfer element configured to be thermally coupled to the second pipe, with each having an elongate portion extending in a direction away from the associated pipe. The elongate portions of the first and second heat transfer elements at least partially overlap. A thermoelectric device is provided that includes one or more thermoelectric elements located between the elongate portions, the thermoelectric element(s) being in thermal communication with the elongate portion of the first heat transfer element and the elongate portion of the second heat transfer element and being arranged to generate electricity from a temperature differential between the elongate portions of the first and second heat transfer elements.

A power generation system according to the present invention includes: a fuel cell unit including a fuel cell, a hydrogen generator having a first combustor, and a case; a controller; a combustion unit including a second combustor; and a discharge passage formed to cause the case and the combustion unit to communicate with each other. In a case where the controller causes one of the first combustor and the second combustor to perform the ignition operation, the controller maintains an operating state of the other combustor during the period of the ignition operation of the one combustor.

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 fenestration assembly comprising a sliding glass assembly that slides between a fully closed position and a fully open position in which the sliding glass assembly is received into a pocket of the fenestration assembly. The pocket is covered on at least one side with insulation. The fenestration assembly may have two sliding glass assemblies. The fenestration assembly may be used in an energy efficient building system.