A heat supply system with a first temperature detection unit that detects a first temperature of hot water in a tank, and a second temperature detection unit that detects a second temperature above the first temperature detection unit. When the first temperature is a first lower limit temperature or less, where a temperature increase operation by a combined heat and power supply device is permitted, a control device operates the combined heat and power supply device and flow state adjustment devices such that a heat medium circulates between the combined heat, power supply device, and hot water storage device. When the second temperature is a second lower limit temperature or less, where a temperature increase operation by a boiler device is permitted, the control device operates the boiler device and the flow state adjustment devices such that the heat medium circulates between the boiler device and hot water storage device.

The shower system has a heat exchanger located in compartment vertically adjacent to the wall of the shower space and closed off by an openable or removable panel. The heat exchanger comprising a helically winding heat exchange conduit with successive windings around a vertical axis in said compartment above the floor of the shower space. A pump coupled to the shower drain pumps warm water to a warm water feed of the heat exchanger, from where it is sprayed on a top winding of the heat exchange conduit. Tap water is fed to the shower head successively via the heat exchange conduit and a heater and/or a mixing element for mixing water from the heat exchanger with water from a supply input for external hot water.

An energy system includes a turbine flue heat exchanger feeding a storage tank arranged to deliver water on a high temperature (90° C.) line to supply circuits. A heat pump and storage tank are arranged to deliver lower temperature (45° C.) water on a low temperature line to the supply circuits. A number of the supply circuits are each arranged to receive high temperature water, receive low temperature water, and use these flows to deliver a process water supply at a desired high, low or intermediate temperature (65° C.). In some each supply circuits the blending is controlled by control of a low temperature line pump according to temperature of the process outlet. The low temperature tank is supplied by a heat pump the inlet of which is fed by a heat recovery heat exchanger which recovers waste heat from a plant, and so it is more efficient than if it received cold water. Electrical energy for the heat pump is at least partly supplied by the high temperature heater gas turbine. Overall, the system has excellent energy efficiency due to the manner in which waste heat is utilized, improved efficiency of a heat pump, and real time control of the high and low water lines.

A hot water returning system according to the present disclosure includes a hot water generator that generates hot water, a hot water line that supplies the hot water to a source of demand, a water returning line that returns the hot water to the hot water generator for preheating the hot water in the hot water line, a pump which pumps the hot water for returning of the hot water, and a processor electrically connected to the pump, and the processor is configured to determine a need for preheating corresponding to whether it is necessary to preheat the hot water and a status for use of hot water corresponding to whether the hot water is supplied to a source of demand, and control the pump based on the need for preheating and the status for use of hot water.

A hot water supply system includes a water supply pipe for supplying cold water, a hot water supply pipe for supplying hot water heated by a hot water supply device, a drain pipe for draining wastewater, a heat exchange device for heating cold water supplied from the water supply pipe using the wastewater, and a flow control mechanism for controlling, when supplying warm water obtained by mixing cold water heated by the heat exchange device and hot water heated by the hot water supply device, the flow rate of the cold water and the flow rate of the hot water so as to maintain the temperature of the warm water. The heat exchange device is a double-pipe, multi-pipe, coil, or spiral heat exchanger.

A system and method for providing hot water to a point of use such as a shower. Waste warm water from said point of use passes through a heat exchanger, where it initially warms incoming mains water, typically to about 34 C. The initially warmed water is heated to its final temperature, typically about 42 C., in a smart boiler. The smart boiler, which typically has a volume of about 40 liters, comprises two chambers with a flexible barrier therebetween. Each chamber is separately heated as needed. Hot water is drawn from one of the two chambers; simultaneously, the other chamber fills with initially warmed water and is heated to its final temperature. When the volume of water in the chamber from which water is being drawn reaches a minimum, the system begins to fill that chamber and to draw water from the other one.

A hot water supply system includes a water supply pipe for supplying cold water, a hot water supply pipe for supplying hot water heated by a hot water supply device, a drain pipe for draining waste water, a heat exchange device for heating cold water supplied from the water supply pipe using the waste water, and a flow rate control mechanism for controlling, when supplying warm water obtained by mixing cold water heated by the heat exchange device and hot water heated by the hot water supply device, the flow rate of the cold water and the flow rate of the hot water so as to maintain the temperature of the warm water.

The shower system has a heat exchanger located in compartment vertically adjacent to the wall of the shower space and closed off by an openable or removable panel. The heat exchanger comprising a helically winding heat exchange conduit with successive windings around a vertical axis in said compartment above the floor of the shower space. A pump coupled to the shower drain pumps warm water to a warm water feed of the heat exchanger, from where it is sprayed on a top winding of the heat exchange conduit. Tap water is fed to the shower head successively via the heat exchange conduit and a heater and/or a mixing element for mixing water from the heat exchanger with water from a supply input for external hot water.

A heat supply system with a first temperature detection unit that detects a first temperature of hot water in a tank and a second temperature detection unit that detects a second temperature above the first temperature detection unit. When the first temperature is a first lower limit temperature or less, where a temperature increase operation by a combined heat and power supply device is permitted, a control device operates the combined heat and power supply device and flow state adjustment devices such that a heat medium circulates between the combined heat, power supply device, and hot water storage device. When the second temperature is a second lower limit temperature or less, where a temperature increase operation by a boiler device is permitted, the control device operates the boiler device and the flow state adjustment devices such that the heat medium circulates between the boiler device and hot water storage device.

Provided is a method of signalling energy usage to a user of a hot water outlet of a hot water supply system, the hot water supply system including: a thermal energy store that is supplied with energy from a source of renewable energy; a renewable energy source; an auxiliary water heater coupled to a networked energy supply; a flow transducer operable, when a water flow passes through the hot water outlet, to provide flow rate data for the water flow; and a processor coupled to the flow transducer; the hot water supply system being operable, under the control of the processor, to heat water that is to be supplied to the hot water outlet to a target system supply temperature using a selection of one or more of the auxiliary water heater, the renewable energy source, and energy from the thermal energy store.