Heat pump system and method for controlling the same

A heat pump system, comprising:

• a compressor configured to compress a refrigerant;
• a refrigerant-water heat exchanger configured to perform heat exchange between compressed refrigerant from the refrigerant-water heat exchanger and inlet water;
• an expansion valve configured to expand the refrigerant condensed in the refrigerant-water heat exchanger;
• an outdoor heat exchanger configured to perform heat exchange between the refrigerant expanded in the expansion valve and outdoor air;
• a high pressure sensor configured to detect a high pressure saturation temperature of the refrigerant compressed in the compressor;
• an inlet water temperature sensor configured to detect a temperature of water flowing into the refrigerant-water heat exchanger;
• a condensation temperature sensor configured to detect a temperature of the refrigerant from the the refrigerant-water heat exchanger;
• an outdoor temperature sensor configured to detect an outdoor temperature;
• and
• a controller, comprising at least one processor, comprising processing circuitry, individually and/or collectively, configured to:
• determine a reference supercooling degree of the refrigerant based on the detection of outdoor temperature by the outdoor temperature sensor and the inlet water temperature by the inlet water temperature sensor and an operating frequency of the compressor, determine a current degree of supercooling of the refrigerant based on detection of the high pressure saturation temperature by the high pressure sensor and condensed refrigerant temperature detected by the condensation temperature sensor, and determine whether the refrigerant leaks by comparing the reference supercooling degree and the current degree of supercooling.