Dryer operating method

1 . A method for operating a dryer, the dryer including a heating device, a tumbler that is configured to receive an object to be dried and that is connected to an exit of the heating device, a fan connected to an exit of the tumbler, a heat exchanger connected to an exit of the fan through a first flow line that is configured to carry a working fluid, a compressor having (i) an entrance connected to a circulation line including the first flow line connected to the exit of the fan and (ii) an exit connected to an entrance of the heat exchanger, a discharge valve connected to an exit of the heat exchanger, a discharge line connected to the exit of the heat exchanger and to the discharge valve, a regeneration line that is branched from the discharge line and connected to the circulation line, and a control valve disposed at the regeneration line, the method comprising:

operating the heating device to thereby heat the working fluid;

based on operating compressor, discharging a portion of the working fluid in the circulation line to an outside of the circulation line to thereby reduce a pressure of the working fluid in the tumbler;

operating the tumbler to thereby dry the object in the tumbler;

operating the control valve to control flow of the working fluid from the regeneration line to the circulation line; and

cooling the object in the tumbler.

2 . The method according to claim 1 , further comprising performing heat exchange through the heat exchanger that is accommodated in an accommodation duct,

wherein the accommodation duct is connected to (i) the first flow line connected to the exit of the fan, (ii) a second flow line that is connected to an entrance of the heating device, and (iii) a third flow line that is connected to an entrance of the compressor.

3 . The method according to claim 1 , further comprising:

opening the discharge valve based on a decrease of the pressure in the tumbler; and

closing the discharge valve based on operating the tumbler to dry the object in the tumbler.

4 . The method according to claim 1 , further comprising communicating the working fluid through the regeneration line to at least one of:

a first part of the circulation line that connects the heating device to the tumbler,

a second part of the circulation line that connects the tumbler to the fan,

a third part of the circulation line that is connected to the exit of the fan, or

a fourth part of the circulation line that is connected to an entrance of the heating device.

5 . The method according to claim 1 , further comprising:

closing the control valve based on a decrease of the pressure in the tumbler; and

opening the control valve based operating the tumbler to dry the object in the tumbler.

6 . The method according to claim 1 , further comprising communicating the working fluid through a plurality of elements of the dryer that comprise:

a gas-liquid separator having (i) an entrance connected to the exit of the heat exchanger, (ii) a gas exit connected to the regeneration line, and (iii) a condensed water exit;

a steam trap connected to the condensed water exit of the gas-liquid separator;

a decompression device disposed at at least one of (i) a flow line that connects the exit of the heat exchanger to the entrance of the gas-liquid separator or (ii) a flow line that connects the gas exit of the gas-liquid separator to the discharge line;

a first bypass line that has two ends connected to respective ends of the decompression device;

a first bypass valve disposed at the first bypass line;

a second bypass line that has two ends connected to respective ends of the steam trap; and

a second bypass valve disposed at the second bypass line.

7 . The method according to claim 1 , further comprising:

stopping operation of the heating device based on a decrease of the pressure in the tumbler.

8 . The method according to claim 1 , further comprising:

supplying at least a portion of the working fluid discharged from the heat exchanger into the circulation line based on operating the tumbler to dry the object in the tumbler.

9 . The method according to claim 1 , further comprising:

stopping operation of the compressor based on the object in the tumbler being cooled.

10 . The method according to claim 1 , further comprising communicating the working fluid through the heat exchanger that comprises:

a first inlet configured to receive the working fluid from the compressor; and

a first outlet configured to discharge the working fluid from the heat exchanger,

wherein the first inlet is disposed at a higher position than the first outlet.

11 . The method according to claim 10 , wherein communicating the working fluid through the heat exchanger further is performed through:

a first header that extends an upward-downward direction and defines the first inlet;

a second header that is spaced apart from the second header in a horizontal direction and extends in the upward-downward direction, the second header defining the first outlet; and

a plurality of first tubes that connect the first header to the second header and are spaced apart from one another by predetermined intervals in the upward-downward direction, each of the plurality of first tubes having two ends that are connected to the first header and the second header, respectively.

12 . The method according to claim 10 , wherein communicating the working fluid through the heat exchanger is performed through:

a plurality of tubes that are spaced apart from one another by predetermined intervals in an upward-downward direction; and

a plurality of return bands, each of the plurality of return bands connecting an exit of one of the plurality of tubes to an entrance of an adjacent one of the plurality of tubes, and

wherein the plurality of tubes comprises:

a top tube that is disposed at an uppermost position among the plurality of tubes in the upward-downward direction, the top tube defining the first inlet, and

a bottom tube that is disposed at a lowermost position among the plurality of tubes in the upward-downward direction, the bottom tube defining the first outlet.

13 . The method according to claim 12 , wherein communicating the working fluid through the heat exchanger is performed through the plurality of tubes and the plurality of return bands that define a single flow path of the heat exchanger from the first inlet to the first outlet.

14 . The method according to claim 1 , further comprising communicating the working fluid through an extraction line that is branched from the circulation line and connected to the entrance of the heat exchanger,

wherein an entrance of the extraction line is configured to face the working fluid carried by the circulation line.

15 . The method according to claim 14 , further comprising performing heat exchange through the heat exchanger that is accommodated in an accommodation duct configured to carry the working fluid,

wherein the entrance of the extraction line is disposed at a center portion of the accommodation duct and configured to receive the working fluid that enters the accommodation duct in a direction perpendicular to a cross-sectional surface of the accommodation duct.

16 . The method according to claim 15 , further comprising communicating the working fluid through the extraction line that comprises:

a first pipe that passes through a wall of the accommodation duct, the first pipe having a first end connected to the compressor and a second end disposed inside the accommodation duct; and

a second pipe that is curved and extends from the second end of the first pipe, the second pipe extending in a longitudinal direction parallel to a flow direction of the working fluid in the accommodation duct, and

wherein an end of the second pipe defines the entrance of the extraction line.

17 . The method according to claim 16 , wherein communicating the working fluid through the extraction line is performed through the second pipe that comprises:

a header having one end connected to the first pipe; and

a plurality of branch lines that are branched from the header, and

wherein each of the plurality of branch lines has one end that is connected to the header and another end that defines the entrance of the extraction line.