A pump system for use with a solar collector system which is used to heat a heat transfer fluid, includes a storage tank and the pump system having a first and second pump arranged in parallel which can pump the heat transfer fluid from the storage tank to a solar collector, so that should one pump fail the other pump can function, wherein the outlet of the first pump and the outlet of the second pump are connected to a valve arrangement, whereby when the first pump operates the outlet of the second pump is substantially closed by the flow from the first pump and when the second pump operates the outlet of the first pump is substantially closed by the flow from the second pump.

A system of capturing waste heat includes a heat recovery unit (20) having a heat exchanger (35) arranged to transfer heat between a fluid circulating in a refrigerant loop (60) and a fluid circulating in a solar loop (70) and another heat exchanger (39) arranged to transfer heat between the fluid in the solar loop (70) and a fluid circulating in a water loop (50). Controllable first, second, and third three-way valves (V1-V3) provide or prevent, depending on fluid temperatures, an A-B, B-C, and A-C flow path through the valve. The first valve (V1) is arranged in the water loop (50) upstream of the second heat exchanger (39). The second (V2) is arranged in the solar loop (70) upstream of the second heat exchanger (39). The third valve (V3) is arranged in the solar loop (70) between the first and second heat exchangers (35, 39).

A method and a control system for a hot water supply system, wherein the hot water supply system includes at least one boiler having a heating fluid input pipe line, the control system comprising: a motorized valve; installed upon the heating fluid input pipe line; a first thermistor installed upon the heating fluid input pipe line; a second thermistor installed within the boiler; a motor mechanically connected to the motorized valve; and a controller, wherein the controller is adapted for opening and closing the motorized valve according to temperature difference between a temperature measurement by the first thermistor and a temperature measurement by the second thermistor, wherein the controller is electrically connected to the motor, to the first thermistor, and to the second thermistor.

This invention provides a system and process to optimize photovoltaic (PV), grid, and other electricity in powering an electric water heater. The system comprises a photovoltaic (PV) controller coupled to a plurality of power input sources and heating elements wherein the heating elements immersed in an electric immersion heater water tank. The PV controller is further configured with control circuitry having an operating efficiency routine calculating optimal use cases from a variety of installation parameters and learned parameters to determine the appropriate power input source and switch between sources accordingly.

Provided is a method of disinfecting a hot water supply system having a plurality of controllable hot-water outlets and a water heating arrangement including an energy store comprising a phase change material that has a phase transition temperature of less than 60 Celsius, the method comprising: informing an operator of a future disinfection event; increasing a hot water supply temperature from a pre-event temperature of less than 60 Celsius to a disinfection temperature; providing a signal to the operator to cause the operator to open a first of the hot water outlets; providing a signal to the operator to close the first outlet after a disinfection period; providing a signal to the operator to open another hot water outlet; providing a signal to the operator to close the another hot water outlet after a disinfection period; and repeating the signalling to the operator to open and then, after a disinfection period, to close each of the plurality of controllable hot-water outlets; reducing the hot water supply temperature to the pre-event temperature of less than 60 Celsius from the disinfection temperature; and indicating to the operator the completion of the disinfection event. A corresponding hot water supply system is also provided, the system preferably including a heat pump.

Appliances, such as hot water heaters, hot water heater controllers, and methods of operating such hot water heaters, that take into consideration the availability and capacity of alternative energy sources so that additional efficiencies can be realized by sensing the availability of an alternative energy source and adjusting the control algorithms used to control the use of the available electric power is provided.

A heat driven liquid close-loop automatic circulating system is provided. This system circulates the liquid in a close-loop by the collected heat in the loop. The system may operate without external power for the pump. The heat driven liquid close-loop automatic circulating system may employ a modified self-powered pump for heated liquid. The pump includes an airtight container for containing the heated liquid, a inlet and a outlet of the heated liquid, further more the modified self-powered pump has a breathing channel with a liquid vapor condensing and reflux structure. The heat driven liquid close-loop automatic circulating system may be a solar heated liquid close-loop automatic circulating system with a solar heat collector.

A thermoregulation apparatus for a solar thermal energy capture system comprising a piping infrastructure in fluid communication with a fluid storage tank and one or more solar thermal energy collectors. The thermoregulation apparatus comprises: (i) a thermostatically actuated valve interposed the piping infrastructure downstream from the one or more solar energy collectors and upstream from the fluid storage tank, and (ii) piping for interconnecting the thermostatically actuated valve with the piping infrastructure, and the fluid storage tank. The thermostatically actuated valve can be configured for diverting the flow of working fluid away from the fluid storage tank when the temperature of the working fluid is below a selected set point for actuating the valve, and for diverting the flow of working fluid to the fluid storage tank when the temperature of the working fluid is about or greater than the selected set point.

A system powers a resistive load with switched direct current (DC) power. The high-speed switching of the resistive load heats up the resistive load with a pseudo-DC current. The resistive load can be a water heater element. The water heater can also have another heating element, which allows the pseudo-DC signal to pre-heat the water heater with local solar power, reducing the need for outside energy to power the other heating element.

A solar photovoltaic (PV) water heating system includes a tank including at least a first heating unit having at least first and second heating elements, at least one of which is switchable; a PV solar collector; an inverter adapted to convert the output from the PV collector to an alternating power supply; a modulator to modulate the alternating power supply from the inverter; a controller adapted to control the modulator and the switching of the or each switchable heating element; wherein the controller is adapted to control the modulator and the switchable heating elements to maximize the energy drawn from the PV collector.