A gas-fired instantaneous water heater including a thermoelectric generator (TEG) and a heat pump that is powered by the TEG to improve efficiency compared to existing water heaters. Water to be heated is circulated through the heat pump, TEG heat exchanger, and primary heat exchanger to produce a stream of heated water. An adjustable firing rate permeable matrix radiant burner is included, in which natural gas and air are combusted to produce combustion products, including heat. The combustion products are condensed in a condensing system to produce cooled and dry exhaust gas.

The present disclosure discloses a defrosting control method, a central controller and a heating system. The defrosting control method comprises: heating fluid in a flow passage between an inlet and an outlet of a first heat source by a second heat source, at least in a part of process of defrosting by the first heat source; acquiring an operation parameter of the first heat source, wherein the operation parameter comprises a water outlet temperature and/or a water return temperature and/or an operation parameter of a compressor of the first heat source, comparing a current value of the acquired operation parameter with a preset range of the operation parameter, and adjusting a heat exchange amount between the second heat source and the fluid when the acquired current value is within the preset range. The defrosting control method, the central controller and the heating system provided by the present disclosure can improve the defrosting efficiency while considering the heating comfort, and ensure the stable operation of the defrosting process.

A heat pump system includes a first unit; a second unit connected to a first flow path of the first unit; and a third unit connected to a second flow path of the first unit and connected to the second unit. The heat pump system can operate in a cooling and water heating mode and a heating and water heating mode, wherein, in the cooling and water heating mode, the heat pump system is configured to switch a switching assembly to a first position and connect the at least one first heat exchangers and the second heat exchanger in series; in the heating and water heating mode, the heat pump system is configured to switch the switching assembly to a second position and connect the second heat exchanger and the at least one third heat exchangers in parallel.

The invention is an apparatus for heating or cooling a room of a building. The apparatus includes a radiant panel supported on a wall, which radiates energy to or from a room. The radiant panel has a conduit for passage of a fluid. The invention also includes a heat exchange device which heats or cools the fluid, which is installed inside the wall between two studs. A first line and second line connect the inlet and outlet to the heat exchange device. A pump that pumps the fluid that is heated or cooled by the heat exchange, whereby the room is heated or cooled depending on whether the fluid is heated or cooled by the heat exchange device.

A solar power system has a photovoltaic module that supplies electrical current derived from sunlight to a heater system of a hot water tank. The heater system uses the electrical energy from the photovoltaic module, and optionally also from a local power grid, to heat water up to a selected maximum stored hot water temperature. Control circuitry senses when the level of electrical power is below a threshold solar-power level, and in response sets the stored hot water temperature for the heater system to a first lower temperature value. The control circuitry also senses when the level of electrical power is above the threshold solar-power level, an in response sets the stored hot water temperature for the heater system to a second elevated temperature value higher than the lower temperature, making advantageous use of solar power when available. A mixing unit adds cold water to set the dispensed water temperature.

A heating system including a water conductor, a valve configured to cooperate with a fluid moving device which together operable to selectively circulate a heat transfer fluid in at least one of a first fluid circuit and a second fluid circuit, a heat exchanger and a blower operable to supply a stream of fluid over the heat exchanger, wherein the heat exchanger is fluidly connected to the first fluid circuit, wherein the heat exchanger being disposed to transfer heat between the heat transfer fluid and the heat exchanger, a coil fluidly connected to the second fluid circuit, wherein the coil is configured to be disposed on a drainage tube to transfer heat between the heat transfer fluid and the coil, a final heat exchanger configured for thermally coupling the first fluid circuit and the water conductor and the second fluid circuit and the water conductor.

A heating system for heat recovery from a liquid with an above-ambient temperature, which separates the heating process into a plurality of preheat stages. The heat pump includes an evaporator coupled to a heat generating apparatus via a first pump to transfer heat and preheat fluid flowing through a first heat exchanger to 31° C.-33° C. A sub-cooler pre-heats the incoming fluid as the second stage to 40° C.-45° C. using residual heat after the condensing step. A condenser coupled to a second heat exchanger heats the preheat fluid discharged from the first heat exchanger to 40° C.-45° C. The condenser is coupled to a storage tank to heat the preheat fluid discharged from the second heat exchanger to 58° C. to 85° C. Heat is transferred through the heat pump from the heat generating apparatus to maintain temperature of the fluid flowing through the second heat exchanger and fluid in the storage tank.

The disclosed technology includes an on-demand water heater which uses a heat pump to heat the fluid. The on-demand heat pump water heater can have a low fluid capacity heating chamber which has an inlet and an outlet, a heat pump for heating the fluid, and a controller to control the heat pump and maintain the temperature of the fluid at a predetermined temperature. The on-demand heat pump water heater can include one or more temperature sensors, flow sensors, fluid mixing valves, or supplemental heat sources.

An apparatus that includes a refrigeration circuit that includes an evaporator, a first condenser and a compressor. The apparatus includes a refrigerant-water heat exchanger that includes a second condenser fluidly coupled to the refrigeration circuit. A control valve is operatively connected to the refrigeration circuit to direct flow of refrigerant through at least one of the first condenser during a dehumidification mode and the second condenser during a water heating mode. A damper is disposed on an upwind side of the evaporator, the damper being operable to reduce airflow across the evaporator during a ventilation mode.

One aspect, as provided herein, is directed to a multi-stage fluid control system for a fluid source heat pump system. This embodiment comprises compressors configured to operate as separate, heat exchange stages, condensers each being fluidly coupled to at least one of the compressors by refrigerant tubing and having intake ends coupled together by a fluid intake manifold. This embodiment further includes output conduits coupled to each of the condensers and that are couplable to a distal location. Further included is a modulating valve control system interposed the output conduits. The modulating valve control system is configured to stage a flow of fluid through the condensers based on a number of operating compressors.