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.

The present inventive concept relates to a water recirculating device (100) comprising: a heating arrangement (120); and a flow path divider (122) placed in a water recirculating path (116) upstream from the heating arrangement (120), wherein the flow path divider (122) is arranged to divide the water recirculating path (116) into a heating path (124) and a non-heating path (126); and wherein a first mixing valve (106) is configured to mix water from the heating path (124) having a first temperature and water from the non-heating path (126) having a second temperature in order to form first temperature regulated water, and wherein a second mixing valve (112) is configured to mix water from the heating path (124) having the first temperature with water from the non-heating path (126) having the second temperature in order to form second temperature regulated water.

A first conduit having a cylindrical upper entrance region with the axis of the cylindrical region oriented vertically, which accepts incoming downwardly flowing hot drain water, a central region of said first conduit below the said entrance region having a conical shape of increasing diameter, reaching a maximum diameter 2-7 times larger than the upper region, the shape then transitioning to a decreasing diameter area of a conical shape, the shape transitioning to a cylindrical lower region with a diameter similar to the upper region diameter; a second conduit for the flow of the shower cold water supply, with a diameter 10-40 times smaller than the maximum diameter of the drain water conduit, and a length 10-40 times longer than the vertical length of the drain water conduit, the second conduit tightly wrapped around the first conduit and in close thermal contact with the first conduit.

The present invention relates to a method and apparatus for transferring heat energy from a waste-liquid, wherein the apparatus (100) comprises at least one heat exchange element (107) for transferring heat energy from waste liquid in a first container (101) to a first target fluid, at least one heat pump element (111) for transferring heat energy from waste-liquid transferred from the first container to the further container (102), at least one selectively operable exit-valve element (115) for selectively providing at least one fluid communication path for allowing waste-liquid to exit from the further container, and at least one controller element for selectively operating the heat pump element to transfer heat energy from waste-liquid in the further container to a further target fluid and/or for selectively operating the at least one selectively operable exit-valve element.

The present invention provides a cold-storage instantaneous heat pump water heater (HPWH). The HPWH includes a cold-water tank, a main evaporator, a compressor, and a hot water heat exchanger. In the present invention, heat of a working medium in the cold-water tank is absorbed by the main evaporator, and bathing water is rapidly heated by the hot water heat exchanger (condenser of the heat pump), thereby realizing instant heating with small input electrical power. Cold-water tank replaces the hot water tank of conventional HPWH avoiding energy loss during hot water storage. The working medium in the cold-water tank absorbs heat from the environment, to further improve energy utilization. In addition, there are three energy recovery evaporators to recover the waste heat of bathing.

The invention relates to a heat recovery unit to transfer heat from a gray water source discharged from a bath or a shower to preheat fresh cold water supplying a bath, a shower, a boiler system or hot water heater. The heat recovery unit comprises an inner tube, an outer tube, a non-return valve, an anode, deflectors as well as associated piping and fittings. Fresh water from a pressurized public network or well flows through the inner tube while the gray water flows between the inner and outer tubes. The non-return valve installed in the fresh water pipe prevents contamination of the drinking water system. A translucent pipe may be installed in a section of the gray water piping system to detect any leaks. An insulated jacket may be placed around the unit to reduce heat loss. The heat recovery unit may be used in domestic, commercial, industrial and institutional buildings.

A heat exchange system for transferring heat energy to control the temperature of a building comprising: a first heat exchanger having a first and second inlet and a first and second outlet wherein waste water flows through said first inlet of said first heat exchanger and out said first outlet while a water supply flows through said second inlet through said first heat exchanger and out said second outlet so as to transfer heat energy between said waste water and said water supply; and a second heat exchanger having a first and second inlet and a first and second outlet wherein domestic water flows through said first inlet, through said second heat exchanger and out said first outlet while said water supply from said second outlet of said first heat exchanger flows through said second inlet, through said second heat exchanger and out said second outlet so as to further transfer heat energy between said domestic water and said water supply from said second outlet of said second heat exchanger and control the temperature of said building.

An apparatus to preferentially temper a liquid (only heat it, or, only cool it) by heat exchange with a fluid of indeterminate temperature. A tank of the liquid is plumbed to a liquid dispenser such as a water faucet, heater or chiller and has a internal heat exchanger sealed through each end. A drainpipe with a slit sleeve for double-wall safety, passes through the housing with an annular space between and is connected to a supply of fluids. A gasket seals the space forming a conduit for the liquid. One end of the housing extends from the tank for the liquid inlet. The conduit has natural convection holes into the tank controlled by convection valves which are moved by convection allowing convection only in the direction which preferentially tempers the liquid in the tank, regardless of the temperature, volume, rate, and time of flow of fluids.

The present inventive concept relates to a water recirculating device (100) comprising: a heating arrangement (120); and a flow path divider (122) placed in a water recirculating path (116) upstream from the heating arrangement (120), wherein the flow path divider (122) is arranged to divide the water recirculating path (116) into a heating path (124) and a non-heating path (126); and wherein a first mixing valve (106) is configured to mix water from the heating path (124) having a first temperature and water from the non-heating path (126) having a second temperature in order to form first temperature regulated water, and wherein a second mixing valve (112) is configured to mix water from the heating path (124) having the first temperature with water from the non-heating path (126) having the second temperature in order to form second temperature regulated water.

The invention relates to a heat recovery unit to transfer heat from a gray water source discharged from a bath or a shower to preheat fresh cold water supplying a bath, a shower, a boiler system or hot water heater. The heat recovery unit comprises an inner tube, an outer tube, a non-return valve, an anode, as well as associated piping and fittings. Fresh water from a pressurized public network or well flows through the inner tube while the gray water flows between the inner and outer tubes. The non-return valve installed in the fresh water pipe prevents contamination of the drinking water system. A translucent pipe may be installed in a section of the gray water piping system to detect any leaks. An insulated jacket may be placed around the unit to reduce heat loss. The heat recovery unit may be used in domestic, commercial, industrial and institutional buildings.