The invention solves the problem of hot water flow in a domestic hot water installation. The subject of the installation according to the invention is that on a third cold water branch (13) that feeds the heating device (1) a control switch (4) is installed, said switch (4) is connected by control system (11) with hot water flow forcing device (3) set on a second hot water circulation branch (2).

A hot water circulation system comprises a water heater having a cold-water inlet and a hot water outlet. A water pump circulates water through the water heater to produce hot water. The hot water is circulated to a thermal bypass valve, which is configured to close when hot water contacts a heat activated seal. A bypass circuit is coupled between the hot water outlet and the cold water inlet of the water heater. The bypass circuit prevents hot water from circulating from the hot water outlet to the cold-water inlet when the thermal bypass valve is open and promotes circulating hot water from the hot water outlet to the cold water inlet when the thermal bypass valve is closed. Upon a temperature sensor sensing hot water entering the cold-water inlet, the water heater turns of the water pump.

A liquid heating appliance for heating water or other liquids, suitably to a target temperature of from 55° C. to around boiling point, includes a primary heat chamber or body (heat source chamber) that is thermally insulated and which in use contains a high thermal density heat storing liquid or solid; and a secondary chamber alongside the primary chamber through which a liquid to be heated is passed in use. The appliance has a heat transfer feature to selectively transfer thermal energy from the heat-storing liquid or solid to the liquid to be heated in the secondary chamber. The secondary chamber is preferably a conduit through which the liquid to be heated is able to flow and the thus heated liquid can be delivered to a tap as hot water for a range of uses. Water may also be heated for a central heating system for space heating.

A modularized combined intelligent heat collector system, comprising a PTCR-xthm electric heating chip heat source main engine, a data control template, a constant-temperature and constant-pressure device and a variable-frequency pump; the variable-frequency pump and the PTCR-xthm electric heating chip heat source main engine are connected to the data control template; the outlet end of the PTCR-xthm electric heating chip heat source main engine is connected to the constant-temperature and constant-pressure device; the outlet end of the constant-temperature and constant-pressure device is connected to the PTCR-xthm electric heating chip heat source main engine through the variable-frequency pump; the PTCR-xthm electric heating chip heat source main engine directly leads out a user heating pipeline; and/or the PTCR-xthm electric heating chip heat source main engine leads out the user heating pipeline through the constant-temperature and constant-pressure device, and is connected to a heat exchanger of a user water heater.

Embodiments described herein generally relate to a domestic hot water (DHW) preheater operable to supply domestic hot water to a structure and/or to preheat a cold return of a space heating system.

A boiler unit comprises an enclosure including: a first circuit of a first fluid heat exchange medium, the first circuit having a heating device to heat the first medium, a boost heat exchanger, a valve and a first manifold; a second circuit of a second heating system fluid heat exchange medium, the second circuit having a flow and return port of the boiler unit, a second manifold and said boost heat exchanger for exchange of heat between said first and second heat exchanger media when said valve is open; a space in the enclosure receiving an auxiliary unit to be driven substantially exclusively by said first fluid heat exchange medium; and a boiler control unit to control operation of the heating device according to heat demand of the heating device and otherwise irrespective of the auxiliary unit when connected; and an organic rankine cycle (ORC) unit comprising: a third fluid heat exchange medium circuit, the circuit including a condenser adapted for connection to said second manifold to provide heat to said second circuit, a pump to circulate said third medium, an evaporator adapted for connection to said first manifold to heat said third medium and a rotary expander connected to an electricity generator; and an auxiliary control unit to control the ORC unit and operate said valve.

A boiler unit comprises an enclosure including: a first circuit of a first fluid heat exchange medium, the first circuit having a heating device to heat the first medium, a boost heat exchanger, a valve and a first manifold; a second circuit of a second heating system fluid heat exchange medium, the second circuit having a flow and return port of the boiler unit, a second manifold and said boost heat exchanger for exchange of heat between said first and second heat exchanger media when said valve is open; a space in the enclosure receiving an auxiliary unit to be driven substantially exclusively by said first fluid heat exchange medium; and a boiler control unit to control operation of the heating device according to heat demand of the heating device and otherwise irrespective of the auxiliary unit when connected; and an organic rankine cycle (ORC) unit comprising: a third fluid heat exchange medium circuit, the circuit including a condenser adapted for connection to said second manifold to provide heat to said second circuit, a pump to circulate said third medium, an evaporator adapted for connection to said first manifold to heat said third medium and a rotary expander connected to an electricity generator; and an auxiliary control unit to control the ORC unit and operate said valve.

A district public water supply pipe network system compatible for ground source heat pump water and reclaimed water comprises a water supply main pipe connected with a reclaimed water outlet side of a sewage treatment system and connected to a plurality of energy stations and a plurality of transmission and distribution station, and a return water main pipe arranged between the adjacent energy stations to connect them. The energy stations are provided with a plurality of shallow geothermal heat exchange system for exchanging heat with shallow geothermal energy in the region. Both the energy stations and the transmission and distribution station are connected with corresponding distribution pipe networks connected with a user terminal water supply system. The system provides the source side water and the reclaimed water to users. It is a district public geothermal pipe network and a reclaimed water pipe network.

A heater with a recovery device for swelling water is provided. A water inlet pipe and a water outlet pipe are longitudinally provided on the heater. The recovery device is transversely disposed on the heater and connected with the water inlet pipe, such that the recovery device is coupled on to reduce the entire size. The recovery device is adapted to recycle and store the swelling hot water in the heater so as to provide an energy-saving effect and to stop water from dripping.

A system is provided for heat recovery from shower greywater. An outlet for greywater is connected to a heat exchanger's inlet for greywater and the heat exchanger is designed so that a cold supply water flows in the opposite direction through the heat exchanger relative to the relatively hot greywater, so that heat exchange works under a counterflow principle and heat energy is transferred from the hot greywater to the cold supply water. A manifold having a nozzle outlet for hot supply water is connected to a waste pipe so that the manifold nozzle outlet for hot supply water opens into the waste pipe at a position downstream of the waste pipe inlet for greywater but upstream of the waste pipe outlet for greywater.