Heat pump and method of operating heat pump to control power to boiler based on expected efficiency of heat pump

A method of controlling a heat pump, the method comprising:

• calculating an expected efficiency of the heat pump based on a first sensed value of a first temperature sensor configured to detect an outdoor temperature and an initial target temperature, which is predetermined based on a temperature of fluid flowing through at least one heating pipe connected to a heating device configured to heat an indoor space, based on the first sensed value being equal to or greater than a predetermined temperature;
• controlling power to a boiler such that the boiler is turned off, based on the expected efficiency being equal to or greater than a predetermined efficiency value;
• calculating a target temperature for the temperature of fluid based on the expected efficiency being less than the predetermined efficiency value;
• controlling the power to the boiler such that the boiler is turned off, based on a second sensed value of a second temperature sensor configured to detect the temperature of fluid being equal to or higher than the target temperature;
• controlling the power to the boiler such that the boiler is turned on, based on the second sensed value of the second temperature sensor being less than the target temperature;
• and
• controlling the power to the boiler such that the boiler is turned on and controlling a compressor of the heat pump to stop operating, based on the first sensed value being less than the predetermined temperature.

A heating system, comprising:

• a boiler having a combustion heating device;
• a heating device configured to heat an indoor space;
• and
• a heat pump, including:
• a compressor configured to compress a refrigerant;
• at least one heating pipe configured to connect to the heating device;
• a first temperature sensor configured to detect an outdoor temperature;
• a second temperature sensor provided in the at least one heating pipe to detect a temperature of fluid flowing through the at least one heating pipe;
• an outdoor heat exchanger configured to perform heat exchange between outdoor air and the refrigerant;
• and
• a controller configured to receive information from the first and second temperature sensors, and to control power to the boiler and to control the compressor based on the information received from the first and second temperature sensors, wherein:
• when a first sensed value of the first temperature sensor is equal to or greater than a first predetermined temperature, an expected efficiency of the heat pump is calculated based on the first sensed value and an initial target temperature of fluid flowing through the at least one heating pipe,
• when the expected efficiency is equal to or greater than a predetermined efficiency value, the boiler is turned off,
• when the expected efficiency is less than the predetermined efficiency value, a target temperature for the temperature of fluid is calculated based on the expected efficiency,
• when a second sensed value of the second temperature sensor is equal to or higher than the target temperature, the boiler is turned off, and
• when the second sensed value of the second temperature sensor is less than the target temperature, the boiler is turned on.