A washing apparatus comprising: a casing having a top cover, a chamber for receiving goods to be washed, a heat pump comprising a first heat exchanger , a second heat exchanger , a compressor and a pressure lowering device forming a circuit comprising a refrigerant (R), the first heat exchanger being adapted to cool said refrigerant and to heat washing water to be used in the chamber , the second heat exchanger being adapted to heat said refrigerant and to cool an auxiliary fluid, and a thermal storage tank adapted to contain a liquid, wherein said second heat exchanger comprises at least one heat exchanger module , said module including: an inlet header to direct a flow of said refrigerant (R) into said module; an outlet header to discharge a flow of said refrigerant (R) from said module; and a plurality of heat exchange layers fluidly connecting said inlet to said outlet header to enable said refrigerant to flow from said inlet to said outlet header and/or vice versa; said layers being stacked one above the other in a predetermined direction, each heat exchange layer including a plurality of channels ; wherein said second heat exchanger is adapted to heat said refrigerant (R) and to cool the liquid contained in the thermal storage tank , said auxiliary fluid being said liquid contained in said thermal storage tank ; and a worktop, said worktop including the top cover and a hollow cavity forming said thermal storage tank . a casing having a top cover, a chamber for receiving goods to be washed, a heat pump comprising a first heat exchanger , a second heat exchanger , a compressor and a pressure lowering device forming a circuit comprising a refrigerant (R), the first heat exchanger being adapted to cool said refrigerant and to heat washing water to be used in the chamber , the second heat exchanger being adapted to heat said refrigerant and to cool an auxiliary fluid, and a thermal storage tank adapted to contain a liquid, wherein said second heat exchanger comprises at least one heat exchanger module , said module including: an inlet header to direct a flow of said refrigerant (R) into said module; an outlet header to discharge a flow of said refrigerant (R) from said module; and a plurality of heat exchange layers fluidly connecting said inlet to said outlet header to enable said refrigerant to flow from said inlet to said outlet header and/or vice versa; said layers being stacked one above the other in a predetermined direction, each heat exchange layer including a plurality of channels ; an inlet header to direct a flow of said refrigerant (R) into said module; an outlet header to discharge a flow of said refrigerant (R) from said module; and a plurality of heat exchange layers fluidly connecting said inlet to said outlet header to enable said refrigerant to flow from said inlet to said outlet header and/or vice versa; said layers being stacked one above the other in a predetermined direction, each heat exchange layer including a plurality of channels ; wherein said second heat exchanger is adapted to heat said refrigerant (R) and to cool the liquid contained in the thermal storage tank , said auxiliary fluid being said liquid contained in said thermal storage tank ; and a worktop, said worktop including the top cover and a hollow cavity forming said thermal storage tank . <EOS>