Water heater and method for controlling the same

1 . A water heater connected to an outdoor unit through first and second refrigerant lines, the outdoor unit including an outdoor heat exchanger that exchanges heat with air, the water heater being connected to a hot water use place to supply hot water through first and second water lines, the water heater comprising:

an electronic component unit provided with control components;

a compressor configured to compress a refrigerant;

a condenser provided on an outlet side of the compressor and configured to perform heat exchange between a refrigerant passage through which the refrigerant compressed in the compressor flows and a water passage through which water transferred from the hot water use place flows;

a condenser outlet pipe extending from an outlet side of the condenser;

a cooling pipe installed in the condenser outlet pipe and configured to supply the refrigerant so as to cool the electronic component unit; and

an evaporator disposed on an outlet side of the cooling pipe and configured to perform heat exchange between a first refrigerant passage through which the refrigerant passing through the cooling pipe flows and a second refrigerant passage through which the refrigerant transferred from the outdoor unit flows.

2 . The water heater of claim 1 , further comprising an additional heat exchanger installed in the condenser outlet pipe,

wherein the additional heat exchanger comprises a first heat exchange portion connected to the condenser outlet pipe and a second heat exchange portion connected to the second refrigerant passage of the evaporator and configured to exchange heat with the first heat exchange portion.

3 . The water heater of claim 2 , wherein the cooling pipe is connected to an outlet side of the first heat exchange portion of the additional heat exchanger, and

wherein a main expansion valve for depressurizing the refrigerant is installed on the outlet side of the cooling pipe.

4 . The water heater of claim 2 , further comprising an evaporator outlet passage extending from an outlet side of the second refrigerant passage of the evaporator to the second heat exchange portion of the additional heat exchanger,

wherein an evaporator-side expansion valve is installed in the evaporator outlet passage so as to depressurize the refrigerant introduced into the second heat exchange portion.

5 . The water heater of claim 4 , further comprising a temperature sensor configured to detect a temperature of the electronic component unit, and a controller configured to adjust an opening degree of the evaporator-side expansion valve based on the temperature detected by the temperature sensor,

wherein the controller is configured to decrease the opening degree of the evaporator-side expansion valve when the controller recognizes that the temperature detected by the temperature sensor changes to increase, and to increase the opening degree of the evaporator-side expansion valve when the controller recognizes that the temperature detected by the temperature sensor changes to decrease.

6 . The water heater of claim 1 , wherein the cooling pipe is installed on a passage through which at least a portion of the refrigerant flowing through the condenser outlet pipe branches and flows.

7 . The water heater of claim 6 , wherein the condenser outlet pipe comprises a branch portion, and

wherein the cooling pipe is installed in a branch pipe branched from the branch portion.

8 . The water heater of claim 7 , wherein the condenser outlet pipe further comprises a joining portion where the branch pipe is joined, and

wherein the water heater further comprises a main expansion valve installed in the condenser outlet pipe for depressurizing the refrigerant at a point between the branch portion and the joining portion.

9 . The water heater of claim 7 , wherein a branch expansion valve is installed in the branch pipe so as to depressurize the refrigerant flowing through the branch pipe, and the branch expansion valve comprises an electric expansion valve that allows an opening degree to be adjusted.

10 . The water heater of claim 9 , further comprising a temperature sensor configured to detect a temperature of the electronic component unit, and a controller configured to adjust the opening degree of the branch expansion valve based on the temperature detected by the temperature sensor,

wherein the controller is configured to increase the opening degree of the branch expansion valve when the controller recognizes that the temperature detected by the temperature sensor changes to increase, and to decrease the opening degree of the branch expansion valve when the controller recognizes that the temperature detected by the temperature sensor changes to decrease.

11 . The water heater of claim 6 , further comprising a supercooler installed in the condenser outlet pipe and a supercooling passage branched from the condenser outlet pipe and connected to the supercooler,

wherein the cooling pipe is installed on the supercooling passage at an outlet side of the supercooler.

12 . The water heater of claim 11 , wherein the condenser outlet pipe further comprises a joining portion where the supercooling passage is joined, and

wherein a main expansion valve is installed in the condenser outlet pipe for depressurizing the refrigerant at a point between the supercooler and the joining portion.

13 . The water heater of claim 11 , wherein a supercooling expansion valve is installed in the supercooling passage so as to depressurize the refrigerant flowing through the supercooling passage, and the supercooling expansion valve comprises an electric expansion valve that allows an opening degree to be adjusted.

14 . The water heater of claim 13 , further comprising a temperature sensor configured to detect a temperature of the electronic component unit, and a controller configured to adjust the opening degree of the supercooling expansion valve based on the temperature detected by the temperature sensor,

wherein the controller is configured to increase the opening degree of the supercooling expansion valve when the controller recognizes that the temperature detected by the temperature sensor changes to increase, and

wherein the controller is configured to decrease the opening degree of the supercooling expansion valve when the controller recognizes that the temperature detected by the temperature sensor changes to decrease.

15 . The water heater of claim 14 , further comprising a supercooling temperature sensor installed in the condenser outlet pipe,

wherein the controller is configured to calculate a supercooling degree based on a temperature of the supercooling temperature sensor when the controller recognizes that the temperature detected by the temperature sensor is higher than or equal to a reference temperature, and to perform control to close the supercooling expansion valve when the supercooling degree is greater than or equal to a predetermined supercooling degree.