A hot water supply apparatus comprises a thermodynamic circuit having a compressor, a condensor for heat exchange between the thermodynamic fluid in the circuit and a high temperature source. That circuit further includes an evaporator arranged for heat exchange with a non-freezable heat carrying fluid which is circulated in a solar energy collecting circuit. A tank receives a body of water for heat storage. An heat exchanger is arranged in the circuit for circulation of the heat carrying fluid and is physically located above the tank. It may be combined with the evaporator. A pump directs a flow of water from the storage tank to sprinkling means associated with the heat exchanger whereby the apparatus operates as ice manufacturing device under severe cold conditions, when there is insufficient heating energy available from the sun.