A method of heating water in a water storage tank. The method includes: selecting an outlet port and an inlet port from at least three ports located in the tank at different heights along a vertical direction. The outlet port is below the inlet port. The method further includes extracting water from the outlet port, supplying the extracted water to an external heat exchanger configured for heating the extracted water, and delivering heated water from the heat exchanger to the selected inlet port.

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 radiant heating system includes a housing and a plurality of heating elements. The housing includes a top cover configured to cover and seal an upper surface of the housing and a coolant directing enclosure positioned on an upper interior surface of the top cover. The top cover includes a plurality of openings, an inlet configured to allow a coolant to enter into the housing and an outlet configured to allow the coolant to exit the housing. The plurality of heating elements are configured to be inserted into the plurality of openings of the top cover such that the plurality of heating elements project into the housing and contact a coolant. A diameter of the inlet is greater than a diameter of the outlet.

The present invention relates to a method of operating an electric motor-driven centrifugal pump (3) in a hydraulic system (4) having at least one self-controlled load, where a gradient (dQ.sub.akt/dt) of the volumetric flow rate (Q.sub.akt) of the centrifugal pump (3) is determined and the current set-point delivery head (H.sub.soll) of the centrifugal pump (3) is calculated from a mathematical operation on the gradient (dQ.sub.akt/dt) weighted with a gain factor (K) and the last specified set-point delivery head (H.sub.soll,alt). The operation describes a positive feedback between the set-point delivery head (H.sub.soll) and the volumetric flow rate (Q.sub.akt). The gain factor (K) is determined from a calculation instruction that is modified dynamically during operation of the centrifugal pump (3) taking into consideration the current operating point of the centrifugal pump (3) and taking into consideration a current and/or at least one past state of the hydraulic system (4).

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 circulation pump assembly includes a first inlet (84), an outlet (80), an electric drive motor (30) and at least one impeller (68; 100) driven by the drive motor (30). The circulation pump assembly has at least one first flow path (26; 48) positioned in a connection between the first inlet (84) and the outlet (80) for increasing the pressure of a fluid. The circulation pump assembly has a second inlet (86). The at least one impeller (68; 100) has at least one second flow path (28; 50) for increasing the pressure of a fluid, which is positioned in a connection of the second inlet (86) to the outlet (80). A heating system is provided having a circulation pump assembly of this type.

A heat pump assembly (100) is presented. The heat pump assembly (100) comprises a heat pump (110) having a primary side inlet (122) and a primary side outlet (124); a primary side inlet valve assembly (126) comprising: a primary side inlet connection (126a) connected to the primary side inlet (122), a primary side inlet valve first conduit connection (126b) configured to be connected to a first conduit (12) of a thermal energy grid (10), and a primary side inlet valve second conduit connection (126c) configured to be connected to a second conduit (14) of the thermal energy grid (10); a first conduit temperature determining device (105a) configured to measure a local temperature, t.sub.1, of heat transfer liquid of the first conduit (12); a second conduit temperature determining device (105b) configured to measure a local temperature, t.sub.2, of heat transfer liquid of the second conduit (14); and a controller (108). The controller is configured to: receive hand t.sub.2 from the first and second conduit temperature determining devices (105a; 105b), receive information pertaining to whether the heat pump (110) is a heating mode heat pump or a cooling mode heat pump. The controller is configured to upon the heat pump (110) is the heating mode heat pump and upon t.sub.2>t.sub.1 set the primary side inlet valve assembly (126) to fluidly connect the primary side inlet valve first conduit connection (126b) and the primary side inlet connection (126a), primary side inlet valve assembly (126) to fluidly connect the primary side inlet valve or upon the heat pump (110) is the heating mode heat pump and upon t.sub.1>t.sub.2, set the second conduit connection (126c) and the primary side inlet connection (126a). The controller is configured to upon the heat pump (110) is the cooling mode heat pump and upon t.sub.1>t.sub.2, set the primary side inlet valve assembly (126) to fluidly connect the primary side inlet valve second conduit connection (126c) and the primary side inlet connection (126a), or upon the heat pump (110) is the cooling mode heat pump and upon t.sub.2>t.sub.1, set the primary side inlet valve assembly (126) to fluidly connect the primary side inlet valve first conduit connection (126b) and the primary side inlet connection (126a).

A solar thermal assisted water heating system includes a thermal collector comprising a plurality of fluid channels configured to collect heat from a surface of a photovoltaic module, a drain-back tank coupled to the thermal collector, a first pump coupled to the drain-back tank and configured to pump fluid from the drain-back tank to the thermal collector, a first heat exchanger configured to receive fluid from the thermal collector, a heat pump coupled to the first heat exchanger and configured to remove heat from the fluid and heat water with the removed heat, and a controller configured to control the first pump and heat pump. The system may include a photovoltaic module and a hot water tank. These systems improve the efficiency of water heating, and the drain-back tank may serve as a thermal battery that stores heat and provides the stored heat when environmental temperatures decrease.

A hot water energy storage system (100) comprises a storage vessel (102); a pump (151); a heat exchanger (152) arranged to receive water from the storage vessel (102) and to output water to the storage vessel (102); a diverting valve (158) to divert a proportion of the water output from the heat exchanger (152) back to an inlet of the heat exchanger (152), bypassing the storage vessel (102); a temperature sensor (120a-c) to measure a temperature of water within the system (100); and a control system (130). The control system (130) controls the pump (151) and the diverting valve (158), based on a temperature measurement of the water and the desired quantity of heat to be transferred by the heat exchanger (152), so as to maintain the return temperature of water entering the storage vessel (102) within a specified range whilst transferring the desired quantity of heat.

A hot water supply system decouples an intelligent hot water storage system from a water heating engine system. The water heating engine system includes a plurality of instantaneous water heaters that provide for redundant operation for improved reliability. The intelligent hot water storage system includes a storage tank that encloses a volume for storage of water. The intelligent hot water storage system includes a recirculation loop driven by an integrated pump and operated by an integrated controller. By positioning the tank recirculation outlet and inlet farther apart from each other, additional usable volume of hot water is provided by the intelligent hot water storage system. Isolation valves positioned on the input and output of a recirculation pump in the recirculation loop facilitate repair or replacement of the recirculation pump. The hot water system provides for increased capacity while providing redundant heating engines in a smaller floor space than conventional systems.