Heat pump and method for controlling operation of boiler based on temperature of fluid
A heat pump may include a compressor configured to compress a refrigerant, a first temperature sensor configured to detect an outdoor temperature, a second temperature sensor provided in heating pipes connected to a heating device that performs indoor heating and configured to detect a temperature of fluid flowing through the heating pipes, an outdoor heat exchanger configured to perform heat exchange between outdoor air and a refrigerant, a third temperature sensor configured to detect a temperature of the outdoor heat exchanger, and a controller. The controller may be configured to: control power to a boiler and/or to the compressor based on sensing values of the first, second, and third temperature sensors, calculate an expected efficiency of the heat pump based on the sensing value of the first temperature sensor and an initial target temperature, and control power to the boiler based on the expected efficiency.
1. A heat pump, comprising:
a compressor configured to compress a refrigerant;
at least one heating pipe configured to connect to a heating device including a tube through which a fluid flows for heating an indoor space;
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;
a third temperature sensor configured to detect a temperature of the outdoor heat exchanger; and
a controller configured to receive information from the first, second, and third temperature sensors, and to control power to a boiler and to control the compressor based on the information received from the first, second, and third temperature sensors, such that:
when a first sensed value of the first temperature sensor is less than a first predetermined temperature, the boiler is turned on and the compressor is turned off;
when the first sensed value is equal to or greater than the first predetermined temperature, an expected efficiency of the heat pump is calculated based on the first sensed value and an initial target temperature, which is predetermined based on a relation to a temperature of fluid flowing through the at least one heating pipe;
when the expected efficiency is less than a predetermined efficiency value, power to the boiler is controlled according to a second sensed value of the second temperature sensor; and
when the expected efficiency is equal to or greater than the predetermined efficiency value, power to the boiler is controlled according to a third sensed value of the third temperature sensor.
2. The heat pump of claim 1 , wherein the heating device is in communication with the heat pump via the at least one heating pipe.
3. The heat pump of claim 1 , wherein the boiler is in communication with the heat pump via the at least one heating pipe.
4. The heat pump according to claim 1 , wherein the controller is configured to:
calculate an expected capability of the heat pump based on the first sensed value;
calculate an expected power consumption of the heat pump based on the expected capability, the initial target temperature, and the first sensed value; and
calculate the expected efficiency by dividing the expected capability by the expected power consumption.
5. The heat pump according to claim 4 , wherein the predetermined efficiency value is determined according to a ratio between an electric rate and a gas rate.
6. The heat pump according to claim 4 , wherein the controller is configured to:
when the expected efficiency is equal to or greater than the predetermined efficiency value, turn off the boiler and determine whether the third sensed value is less than a predetermined low temperature;
when the third sensed value is less than the predetermined lowest temperature, control the power to the boiler based on the second sensed value; and
when the third sensed value is equal to or greater than the predetermined low temperature, maintain the boiler to be turned off.
7. The heat pump according to claim 6 , wherein the controller is configured to:
when the expected efficiency is less than the predetermined efficiency value, or when the third sensed value is less than the predetermined low temperature, calculate a target temperature for the temperature of fluid flowing through the at least one heating pipe based on the expected efficiency;
when a difference value obtained by subtracting the second sensed value from the target temperature is greater than or equal to a predetermined difference, control the power to the boiler such that the boiler is turned on; and
when the difference value is less than the predetermined difference, control the power of the boiler such that the boiler is turned off.
8. The heat pump according to claim 7 , further comprising:
a heat exchange device including a water-refrigerant heat exchanger configured to perform heat exchange between fluid and the refrigerant; and
a fourth temperature sensor configured to detect a temperature of fluid flowing into the heat exchange device, wherein the controller is configured to calculate the target temperature based on the expected efficiency, the third sensed value, and a fourth sensed value of the fourth temperature sensor.
9. The heat pump according to claim 8 , wherein the controller is configured to:
determine whether the first sensed value is changed by more than a predetermined change value; and
when the first sensed value is changed by more than the predetermined change value, recalculate the expected efficiency based on the first sensed value.
10. The heat pump according to claim 9 , further comprising a valve provided in a boiler supply pipe through which fluid discharged from the boiler flows, wherein the controller is configured to:
when the boiler is turned on, open the valve; and
when the boiler is turned off, close the valve.
11. The heat pump according to claim 9 , wherein the controller is configured to:
when the expected efficiency is less than the predetermined efficiency value, or when the third sensed value is less than the predetermined low temperature, check a number of times a state of the power to the boiler has changed, and when the number of times the state of the power of the boiler has changed exceeds a predetermined number, control a degree to which the boiler supply valve is opened according to the difference value.
12. A method of controlling a heat pump, comprising:
when a first sensed value of a first temperature sensor configured to detect an outdoor temperature is less than a first predetermined temperature, controlling power to a boiler so that the boiler is turned on and controlling a compressor to stop operating;
when the first sensed value is equal to or greater than the first predetermined temperature, calculating an expected efficiency of the heat pump based on the first sensed value and an initial target temperature, which is predetermined in relation to a temperature of fluid flowing through at least one heating pipe connected to a heating device including a tube through which a fluid flows for heating an indoor space;
when the expected efficiency is less than a predetermined efficiency value, controlling the power to the boiler according to a second sensed value of a second temperature sensor configured to detect the temperature of fluid flowing through the at least one heating pipe; and
when the expected efficiency is equal to or greater than the predetermined efficiency value, controlling the power to the boiler according to a third sensed value of a third temperature sensor configured to detect a temperature of an outdoor heat exchanger, the outdoor heat exchanger configured to perform heat exchange between outdoor air and a refrigerant.
13. The method of claim 12 , wherein the calculating of the expected efficiency comprises:
calculating an expected capability of the heat pump based on the first sensed value;
calculating an expected power consumption of the heat pump based on the expected capability, the initial target temperature, and the first sensed value; and
calculating the expected efficiency by dividing the expected capability by the expected power consumption.
14. The method of claim 12 , wherein the predetermined efficiency value is determined according to a ratio between an electric rate and a gas rate.
15. The method of claim 12 , wherein the controlling of the power to the boiler according to the third sensed value comprises:
when the expected efficiency is equal to or greater than the predetermined efficiency value, controlling the power to the boiler such that the boiler is turned off and determining whether the third sensed value is less than a predetermined low temperature;
when the third temperature sensor is less than the predetermined low temperature, controlling the power to the boiler according to the second sensed value; and
when the third sensed value is equal to or greater than the predetermined low temperature, controlling the power to the boiler such that the boiler is maintained to be turned off.
16. The method of claim 15 , wherein the controlling of the power to the boiler according to the second sensed value comprises:
when the expected efficiency is less than the predetermined efficiency value, or when the third sensed value is less than the predetermined low temperature, calculating a target temperature for the temperature of fluid flowing through the at least one heating pipe based on the expected efficiency;
when a difference value obtained by subtracting the second sensed value from the target temperature is greater than or equal to a predetermined difference, controlling the power to the boiler so that the boiler is turned on; and
when the difference value is less than the predetermined difference, controlling the power to the boiler so that the boiler is turned off.
17. The method of claim 16 , wherein the calculating of the target temperature is based on the expected efficiency, the third sensed value, and a fourth sensed value of a fourth temperature sensor configured to detect a temperature of fluid flowing into a heat exchange device, and wherein the heat exchange device includes a water-refrigerant heat exchanger configured to perform heat exchange between fluid and the refrigerant.
18. The method of claim 17 , further comprising:
determining whether the first sensed value is changed by more than a predetermined change value; and
when the first sensed value is changed by more than the predetermined change value, recalculating the expected efficiency based on the first sensed value.
19. The method of claim 18 , further comprising:
when the boiler is turned on, opening a valve provided in a boiler supply pipe through which fluid discharged from the boiler flows; and
when the boiler is turned off, closing the valve.
20. The method of claim 19 , further comprising:
when the expected efficiency is less than the predetermined efficiency value, or when the third sensed value of the third temperature sensor is less than the predetermined low temperature, checking a number of times a state of the power to the boiler has changed; and
when the number of times the state of the power to the boiler has changed exceeds a predetermined number, controlling a degree to which the valve is opened according to the difference value.