CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is based on and claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2019-0034233, filed on Mar. 26, 2019 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND

1. Technical Field

The disclosure relates to a clothes dryer including a heat pump system, and a control method thereof.

2. Description of the Related Art

In general, a clothes dryers can be classified into an air vent type, a condenser type, and a heat pump type. The heat pump type clothes dryer may include a heat pump system including a compressor, a condenser, an expander, and an evaporator to heat air, and an air circulation system for supplying the air heated after heat exchange with the condenser to a laundry container.

Refrigerant used in the conventional heat pump system uses a nonflammable refrigerant that does not cause an explosion or fire, but the use of the nonflammable refrigerant is prohibited because it destroys the ozone layer in the atmosphere or accelerates global warming. Therefore, a refrigerant which does not contribute to ozone layer destruction and global warming is used as the refrigerant of the heat pump system, but a flammability problem emerged. Flammable refrigerants may explode or cause fire if a certain amount or more exists in a certain space and the refrigerant temperature is above the ignition temperature.

On the other hand, the prior art related to a heat pump discloses a gas sensor for detecting the leakage of such flammable refrigerant. However, the gas sensor disclosed in the prior art detects the flammable refrigerant from a temperature outside the heat pump system and has a low precision.

In addition, a method of measuring the temperature and pressure of the refrigerant in the prior art is a technique for protecting the compressor before the operation of the heat pump system and is irrelevant to improving the efficiency of the operation of the heat pump.

SUMMARY

Therefore, it is an aspect of the disclosure to provide a clothes dryer for performing accurate measurements of a state of a refrigerant that affects system efficiency during operation and for ensuring the efficiency of performance by specifying a position of a temperature sensor and a pressure sensor provided in a heat pump, and a control method of the clothes dryer.

In addition, it is another aspect of the disclosure to provide a clothes dryer for measuring leakage of a flammable refrigerant and for promoting user safety, and a control method of the clothes dryer.

In accordance with one aspect of the disclosure, a clothes dryer includes: a refrigerant pressure sensor provided in at least one of a first pipe connecting an expander and an evaporator or a second pipe connecting the evaporator and a compressor; a refrigerant temperature sensor provided in the second pipe; an electronic expansion valve configured to control a refrigerant; and a controller configured to control the electronic expansion valve based on detection values of the refrigerant pressure sensor and the refrigerant temperature sensor.

The controller may be configured to calculate a saturation temperature based on the detection value of the refrigerant pressure sensor.

The controller may be configured to compare the calculated saturation temperature and the detection value of the refrigerant temperature sensor and control the electronic expansion valve based on the comparison result.

The controller may be configured to compare the difference between the calculated saturation temperature and the detection value of the refrigerant temperature sensor with a preset reference value, and increase a degree of opening of the electronic expansion valve when the difference between the calculated saturation temperature and the detection value of the refrigerant temperature sensor exceeds the reference value.

The controller may be configured to receive the detection values of the refrigerant pressure sensor and the refrigerant temperature sensor based on a preset period and determine whether to control the electronic expansion valve at each preset period.

The clothes dryer may further include: a temperature sensor configured to detect a temperature of air sucked into the clothes dryer, and the controller may be configured to determine the refrigerant amount based on the detection values of the temperature sensor and the refrigerant pressure sensor.

The controller may be configured to input the detection values of the temperature sensor and the refrigerant pressure sensor into a preset prediction function and calculate the refrigerant amount of a heat pump based on a result of the prediction function.

The controller may be configured to compare the calculated refrigerant amount and a preset reference value.

The controller may be configured to output a warning based on a comparison result of the calculated refrigerant amount and the preset reference value before operation of the heat pump.

In accordance with another aspect of the disclosure, a control method of a clothes dryer, includes: detecting a pressure of a refrigerant through a refrigerant pressure sensor provided in at least one of a first pipe connecting an expander and an evaporator or a second pipe connecting the evaporator and a compressor; detecting a temperature of the refrigerant through a refrigerant temperature sensor provided in the second pipe; and controlling an electronic expansion valve configured to adjust the refrigerant based on the detection values of the refrigerant pressure sensor and the refrigerant temperature sensor.

The controlling may include: calculating a saturation temperature based on the detection value of the refrigerant pressure sensor.

The controlling may include: comparing the calculated saturation temperature and the detection value of the refrigerant temperature sensor and controlling the electronic expansion valve based on the comparison result.

The controlling may include: comparing the calculated saturation temperature and the detection value of the refrigerant temperature sensor; and increasing a degree of opening of the electronic expansion valve when a difference between the calculated saturation temperature and the detection value of the refrigerant temperature sensor exceeds a reference value.

The control method may further include: receiving measured values of the refrigerant pressure sensor and the refrigerant temperature sensor based on a preset period, and determining whether to control the electronic expansion valve.

The control method may further include: detecting a temperature of air sucked into the clothes dryer through a temperature sensor; determining the refrigerant amount based on the detection values of the temperature sensor and the refrigerant pressure sensor.

The determining may include: inputting the detection values of the temperature sensor and the refrigerant pressure sensor into a preset prediction function; and calculating the refrigerant amount of a heat pump based on a result of the prediction function.

The determining may include: comparing the calculated refrigerant amount and a preset reference value.

The control method may further include: determining whether to operate the clothes dryer based on the comparison result.

The determining whether to operate the clothes dryer may include: outputting a warning before the heat pump is operated when the calculated refrigerant amount is less than the preset reference value.

The determining whether to operate the clothes dryer may include: initiating an operation of the heat pump when the calculated refrigerant amount exceeds the preset reference value.

