Abstract: 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.

Abstract: 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.

Abstract: A method of and system for heating and/or cooling a fluid, the method comprising moving the fluid through a secondary side of a heat exchanger and controlling the temperature of a primary side of the heat exchanger such that the temperature of the primary side of the heat exchanger is maintained substantially at a determined temperature interval from a reference temperature which is a function of at least one of: a temperature of an inlet to the secondary side and a temperature of an outlet of the secondary side.

Abstract: A method of and system for heating and/or cooling a fluid, the method comprising moving the fluid through a secondary side of a heat exchanger and controlling the temperature of a primary side of the heat exchanger such that the temperature of the primary side of the heat exchanger is maintained substantially at a determined temperature interval from a reference temperature which is a function of at least one of: a temperature of an inlet to the secondary side and a temperature of an outlet of the secondary side.