A liquid heating system includes an instantaneous heater (18) having an inlet (20) connected to a reservoir (62). The outlet (22) of the heater is connected to fixtures (72) which use the heated liquid, and is also connected through a return connection (30) to the reservoir. In an idle mode, a pump 40 draws liquid from the reservoir (62), so that the liquid circulates through the heater and back to the reservoir. A controller (52) actuates the heater to heat the liquid to a first setpoint temperature, so that the liquid in the reservoir stabilizes at the first setpoint temperature. In a supply mode, some or all of the heated liquid flows from the outlet to the fixtures (72). Cold liquid is admitted from a supply (60) to the reservoir, and cold liquid desirably also is supplied to the heater inlet along with liquid from the reservoir, so that the heater inlet receives a combination of these. The controller controls the proportion of cold liquid to liquid from the reservoir in the combination, so as to maintain the heater at a setpoint heating rate while also maintaining the temperature of liquid discharged from the heater outlet at or near a setpoint temperature.

A centrifugal pump assembly includes an electric drive motor (6, 8), a driven impeller (14) and a pump casing (2) which surrounds the impeller (14). A movable element (24; 24) is arranged a valve element. A section of the valve element is movable from a released position into a bearing position, fixed on a contact surface (60), by pressure which is produced by the impeller in the pump casing. A control device (64) moves the valve element from one switching position into another switching position and reduces the speed of the drive motor. Upon pressure in the pump casing dropping such that the valve element is no longer fixed on the contact surface and the valve element has been moved into the other switching position, the control device increases the speed of the drive motor again. A method for moving a valve element is provided.

The invention relates to a method for controlling at least one first circulation pump (17b, 17c) of a heating or cooling system (1) having a primary circuit (2, 2a) and a secondary circuit (4, 30a) coupled therewith at a transfer point (3, 29). The first circulation pump (17, 17b, 17c, 17b) conveys a heating or cooling medium in the primary circuit (2, 2a), and in the second secondary circuit (4, 30a), at least one second circulation pump (12, 17d) is located that conveys a heating or cooling medium in at least one partial area of the secondary circuit (4, 30a). The volume flow rate (formula I) of the first circulation pump (17, 17b, 17c, 17b) is controlled in functional dependence on the volume flow rate (formula II) of the secondary circuit (4, 30) behind the transfer point (3, 29). In this way, a demand based, and thus an energy-efficient control of the primary-side circulation pump is achieved. The invention further relates to a pump system, comprising the at least one first and the at least one second circulation pump for carrying out the method.

The heat exchange system is for heating water from a water source and comprises first and second flooded heat exchangers that have steam sides that are each independently fed with steam, but water sides that are serially fed with water through the first heat exchanger then through the second heat exchanger. The system also comprises first and second control valves located at or downstream of subcooled condensate outlets of the first and second heat exchangers, first and second water temperature sensors at or downstream of the heated water outlets of the first and second heat exchangers, and a control device for receiving temperature data from the first and second water temperature sensors and for controlling the first and second control valves. The proportions of the first and second steam sides that are flooded are respectively selectively adjusted by controlling the debit of condensate allowed through the first and second subcooled condensate outlets with the first and second control valves, for allowing heat exchange to the water to be adjusted as a result of the water temperature measured by the first and second water temperature sensors. The first and second control valves are set in one of a first state in which they are both at least partly opened to allow effective heat exchange from the steam to the water in both first and second heat exchangers, and a second state in which one of them is closed while the other is at least partly opened to have an effective heat exchange from the steam to the water in only one of the first or second heat exchangers while the first and second steam sides remain both supplied with steam.

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.

The present invention relates to a hot water storage tank (202, 302, 402, 502, 602, 702), defining a primly storage volume (204, 304, 404, 504, 604, 704), with at least one heat source (212, 312, 412, 512, 612, 712) positioned in and operable to directly heat water in the upper portion (207, 307, 407, 507, 607, 707) of the primary storage volume (204, 304, 404, 04, 604, 704), and a pump or other means (237, 337, 437, 537, 637) that draws water, from the lower portion (209, 309, 409, 509, 609, 709) of the tank into a heat transfer device (216, 316, 416, 516, 616, 716), situated in said upper portion (207, 307, 407, 507, 607, 707). The heat transfer device (216, 316, 416, 516, 616, 716) is configured to enable the transfer of heat from heated water in the upper portion (207, 307, 407, 507, 607, 707) to the drawn water prior to discharge into the water in the upper portion (207, 307, 407, 507, 607, 707).

The purpose of the present invention is to provide a hot water supplying apparatus that enables a user to conveniently execute a hot water control function in a location where a faucet is located, and a method for controlling the same. The hot water supplying apparatus for achieving said purpose comprises: a flow rate detection unit for detecting a flow rate change of water supplied by turning a faucet on/off and outputting a flow rate signal; and a control unit for, when the flow rate detection unit detects a flow rate change in a specific pattern, controlling a preset hot water control function to be executed according to the flow rate change pattern.

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 water-heating system, including: a controller; a refrigerant-water heat exchanger for exchanging heat between refrigerant and water; a sensor circuit for measuring a current water temperature of water in a water heater and providing the current water temperature to the controller; a first refrigerant pipe for passing the refrigerant from a refrigerant source to the refrigerant-water heat exchanger; a second refrigerant pipe for passing the refrigerant from the refrigerant-water heat exchanger to the refrigerant source; a first water pipe for passing the water from the water heater to the refrigerant-water heat exchanger; a second water pipe for passing the water from the refrigerant-water heat exchanger to the water heater; and a water pump for pumping water from the water heater to the refrigerant-water heat exchanger via the first water pipe and from the refrigerant-water heat exchanger to the water heater via the second water pipe based on a control signal.

A water heater includes a heat exchanger. A controllable three-way proportional valve provides a proportionally controllable flow to the hot water inlet of the heat exchanger and a boiler return water outlet. A mixing tank mixes a cold water and a hot water. The mixing tank provides a time delayed mixed water. A temperature sensor is disposed in or on the mixing tank to measure a temperature of the time delayed mixed water to provide a time delayed mixed water temperature. A feedforward control process running on a processor adjusts a proportional operating position of the controllable three-way proportional valve to regulate a temperature of hot water at the hx domestic hot water outlet based on the temperature of the time delayed mixed water temperature. A method for controlling a hot water temperature of a water heater a water heater using a flowmeter based feedforward control are also described.