Storage type heat pump hot water supplying apparatus

A storage type heat pump hot water supplying apparatus, comprising:

• a heat source machine including a compressor to compress refrigerant and a water heat exchanger to exchange heat between water and the refrigerant compressed by the compressor;
• a hot water storage tank to store hot water heated by the heat source machine;
• a water circuit including a feed path connecting a lower part of the hot water storage tank to a water inlet of the water heat exchanger, a return path connecting a water outlet of the water heat exchanger to an upper part of the hot water storage tank, and a water pump provided in the feed path or the return path;
• a temperature sensor to detect an actual hot water discharge temperature, the actual hot water discharge temperature being a temperature of hot water flowing out of the water heat exchanger;
• and
• control circuitry to control a compressor frequency and a pump rotational speed, the compressor frequency being an operating frequency of the compressor, the pump rotational speed being a rotational speed of the water pump,
• wherein the control circuitry is configured to control, in a heat accumulating operation for accumulating hot water in the hot water storage tank, the pump rotational speed so that the actual hot water discharge temperature becomes equal to a target hot water discharge temperature,
• wherein the heat accumulating operation includes a first operation and a second operation after the first operation,
• wherein the compressor frequency in the first operation is higher than the compressor frequency in the second operation, and
• wherein the target hot water discharge temperature in the first operation is lower than the target hot water discharge temperature in the second operation.