Methods and systems for performing a heat pump defrost cycle

A non-transitory computer-implemented method of defrosting a heat pump of a water provision system installed in a building, the water provision system comprising:

• the heat pump, a thermal energy storage medium, at least one valve, and a control module, wherein the heat pump is configured to transfer thermal energy from outside the building to the thermal energy storage medium inside the building and wherein the control module comprises at least one processor executing software instructions to control operation of the heat pump, the thermal energy storage medium, and the at least one valve to direct water heated by the thermal energy storage medium to an occupant of the building at one or more water outlets, the non-transitory computer-implemented method comprising:
• determining, by the at least one processor of the control module, an expected start time of a next defrost cycle of the heat pump, wherein the expected start time is a predicted time by the at least one processor of the control module before the next defrost cycle begins and is based on performance of the heat pump;
• and
• before the expected start time of the next defrost cycle of the heat pump, operating the heat pump for a predetermined time period before the expected start time of the next defrost cycle of the heat pump to pre-charge the thermal energy storage medium to store thermal energy in the thermal energy storage medium such that the thermal energy storage medium reaches a first temperature higher than its normal operating temperature before the expected start time;
• and
• wherein an amount of thermal energy stored in the thermal energy storage medium arising from the pre-charge prevents disruption of the heated water delivery to the occupant during the next defrost cycle.