Heat pump

A heat pump, comprising:

• an outdoor device comprising a compressor;
• a hydro-device comprising at least one heat exchanger that heat-exchanges refrigerant supplied by the outdoor device with water;
• a boiler configured to selectively heat water circulating through the hydro-device or water supplied from a commercial water supply system;
• a radiation heater configured to perform heating using water heated by at least one of the hydro-device or the boiler, wherein water circulating through the hydro-device and the radiation heater selectively passes through the boiler based on a temperature of external air;
• a quick-hot-water-supply tank configured to heat and store water supplied by the commercial water supply system using the water heat-exchanged with the refrigerant in the hydro-device or to store, after heating, the water supplied by the commercial water supply system;
• and
• a controller configured to control the outdoor device, the hydro-device, and the boiler, wherein the boiler is operated when the temperature of the external air is less than a predetermined first temperature below approximately 0° C. and the hydro-device is operated when the temperature of the external air is equal to or greater than the predetermined first temperature;
• wherein when the temperature of the external air is equal to or greater than the predetermined first temperature and less than a predetermined second temperature above approximately 0° C. which is greater than the predetermined first temperature, water circulating through the radiation heater, after being heat-exchanged with the refrigerant in the hydro-device, passes through the boiler and only a pump provided in the boiler is operated, without a combustion process;
• wherein when the temperature of the external air is equal to or greater than the predetermined second temperature above approximately 0° C., the water circulating through the radiation heater, after being heat-exchanged with the refrigerant in the hydro-device, bypasses the boiler;
• wherein the controller is connected to an energy management system that provides information on an electric power rate, wherein the energy management system provides information on the electric power rate per unit heat quantity for a predetermined period of time or the energy management system transmits a control signal of the heat pump to the controller, based on the information on the electric power rate per unit heat quantity;
• wherein when a user sets a peak rate per unit heat quantity using the energy management system or the controller, the energy management system or the controller compares the electric power rate unit heat quantity and a gas rate per unit heat quantity with the set peak rate per unit heat quantity, and the boiler is operated only in a period during which the electric power rate per unit heat quantity is higher than the set peak rate per unit quantity;
• and wherein operation of the hydro-device is stopped and the boiler operated, when the temperature of the external air is equal to or less than the predetermined first temperature below approximately 0° C., even in a case in which the electric power rate per unit heat quantity is lower than the set peak rate per unit heat quantity.