KR101536819B1 - Heat pump dryer - Google Patents

Abstract

The present invention relates to a heat pump dryer that efficiently dries an object to be dried by drying the object using condensation heat of a heat pump and condensing and removing moisture generated during the drying process using the cold generated in the evaporator, Is a heat pump dryer configured to maintain the internal temperature of the dryer up to 80 ° C without reducing the efficiency of the heat pump in order to solve the problem of the conventional heat pump dryer in which the internal temperature of the dryer should be limited to 50 ° C or less will be.

Description

Heat Pump Dryer {HEAT PUMP DRYER}

The present invention relates to a heat pump dryer in which drying efficiency is enhanced by drying an object using condensation heat of a heat pump and condensing and removing moisture generated in the drying process by using the cold heat generated in the evaporator, In the dryer, the heat remaining in the condenser is absorbed by the evaporator to improve the efficiency, and it is possible to quickly raise the temperature at an early stage without using an external heat source, prevent the evaporation part from being caught in the winter, The present invention relates to a heat pump dryer capable of maintaining a relatively high temperature.

The heat pump dryer dries the object with the hot hot air obtained from the condenser using the heat flow circulation including the cooling cycle circulating the compressor-condenser-expansion valve-evaporator-compressor and the condenser-cooler-drying chamber, This is a system to efficiently dry the object by condensing and removing water inside the dryer by using the cold heat obtained from the dryer.

Such a heat pump dryer is advantageous in that it can save about 60 ~ 80% of energy compared with the existing hot air drying system which discharges waste heat as it generates heat and absorption of waste heat and condensation of water continuously in a single system Therefore, it can be usefully used in various fields such as drying of agricultural and marine products, manufacturing process of industrial products.

The drying efficiency of an object containing moisture is determined by the appropriate temperature inside the drying chamber and the maintenance of low humidity. In the heat pump drying, the object is heated using the heat generated in the condensing part constituting the cooling cycle, and the generated water is condensed and removed by using the cold heat obtained from the evaporating part, so that the heat including the condensing part and the evaporating part A structure in which a pump system is separated or packaged has been generally applied.

However, the existing heat pump dryer has a limit to be utilized for a limited purpose such as low temperature drying or freeze drying due to the following problems even though it is a highly efficient drying system.

First, there is a problem that it is difficult to raise the initial temperature.

In order to increase the drying efficiency of the object, it is necessary to keep the inside temperature of the drying room at least 50 ° C or more, and a high temperature of 70-80 ° C is required depending on the purpose of use.

In the heat pump system, the condensation part and the evaporation part are installed in the closed drying room, so that the condensation heat and the evaporation heat are almost in thermal equilibrium, and it is difficult to raise the room temperature. Therefore, there is a problem that a separate heat source must be installed inside the drying chamber for the initial heating.

Second, it is difficult to maintain high temperature over 50 캜.

For effective operation of the dryer, it should be possible to maintain the temperature at 70 ~ 80 ℃. For example, red pepper, one of the representative dry agricultural products, should be dried at a moisture content of about 80% to 15%, and an optimal drying temperature of about 60 ° C, which is lower than that, increases the yield rate of decoloration and decay. It is known that when the drying temperature of the heat pump dryer is 40 ~ 50 ℃, the discoloration rate is up to 30%. Maintaining the drying temperature in the heat pump dryer is an important factor for improving the usability and drying efficiency.

In the heat pump dryer, when the temperature inside the dryer is maintained at 50 ° C or more, the condensation portion inlet temperature and the exhaust temperature difference of the refrigerant are not sufficient, so that the gas which is not condensed and liquefied is applied to the expansion valve, thereby decreasing the efficiency of the circulation cycle and increasing the evaporation temperature. In a typical heat pump (without using an expensive high-temperature compressor), the temperature of refrigerant discharged from the compressor is approximately 110 ° C. When the temperature inside the dryer is maintained at 50 ° C or less, heat is taken away from the condenser by heat exchange and is drawn into the expansion valve A balance between evaporation and condensation is achieved, allowing continuous drying operation without cycle problems.

However, if the internal temperature of the drying chamber is raised to 50 ° C or more by using an external heat source or the like, a part of the refrigerant is condensed by the high temperature of the refrigerant after condensation (that is, heat is left after condensation due to insufficient heat exchange in the condensing portion) The expansion efficiency is reduced due to the introduction into the expansion valve in the gaseous state, the high temperature refrigerant gas is drawn into the compressor, and the mechanical lifting due to the high temperature compression and the decompression of the compressor due to the carbonization of the oil occur.

Due to these problems, many attempts and technical development efforts are underway to obtain high temperature by the system. For example, in the case of a single compressor, a high-pressure operation method of operating at a relatively high pressure, a two-stage compression method of increasing the compression degree by connecting two compressors in series, and a high-pressure operation method by using a special high- have.

The high - pressure operation method using a single compressor provides a temperature increase effect of 5 ~ 10 ℃ compared to the normal operation by operating higher than the proper operating pressure of the compressor, but it is 5 ~ 7kg / ㎠ higher than the normal operation pressure around 20kg / It is impossible to perform continuous operation by applying a mechanical force to the compressor due to operation with pressure, and the life of the compressor is extremely shortened due to wear and carbonization of the oil, so that there is a problem that the expensive compressor must be replaced periodically.

The two-stage compression method uses a general refrigerant to compress the refrigerant at 50 ° C in a primary compressor, and compresses the refrigerant in stages at 70 ° C in a secondary compressor using a high-temperature refrigerant to maintain the room temperature at about 20 ° C And it is usefully used as a method of obtaining a lower temperature in the refrigeration field. However, since the remaining heat of the condensation must be discharged before the evaporation, energy efficiency is low, and a small problem is accumulated in the circulation cycle due to condensation and evaporation, There is a disadvantage that costs are increased by about 3 times as much as the existing technology due to the application of a high-pressure compressor and the use of a high-pressure component.

The method using special high-temperature high-pressure compressor has advantages of high-temperature and high-temperature operation by using the same refrigerant and provides a temperature increase effect of about 10 ° C. compared with the conventional method. However, There is a problem that can not be completed.

Korean Patent Publication No. 90-000269 (Jan. 24, 1990) discloses that before the air in the drying compartment is sucked into the evaporator, the temperature is lowered to a proper temperature of about 40 ° C or less, which can sufficiently exhibit the capacity of the refrigerator, So that the drying air in the drying oven can be maintained at a high temperature while the refrigeration system can be operated continuously for a long time in an abnormal state.

Korean Patent Laid-Open Publication No. 10-2011-0068616 (Jun. 22, 2011) discloses a heat exchanger having two cycles of a first heat pump and a second heat pump each comprising a compressor, a condenser, an expansion valve and an evaporator, In the evaporator, the high-temperature air sucked from the dryer is stepped down to be transferred to the condenser, and the refrigerant of the heat pump located on the high- And a compressor capable of withstanding high temperatures, so that even if the internal temperature of the dryer is maintained at a high temperature, it is possible to accommodate the refrigerant in a high-temperature evaporator and a compressor.

The former is a drying device. The principle is that the high-temperature dry air should not be directly sucked into the evaporator in large quantities in order to operate continuously for a long period of time without any difficulty, and that the large amount of dry air is not sucked in the evaporator unlimitedly, The present invention is characterized in that it is possible to continuously operate the refrigeration apparatus in an abnormal state for a long period of time while keeping the drying air at a high temperature. However, since only a part of air in the drying compartment is passed through the evaporator, There is a limit to improvement of drying performance and a part of the air passing through the evaporator is replaced with outside air, resulting in heat loss, which lowers the overall energy efficiency.

In the latter case, it is advantageous to keep the inside of the drying chamber at a high temperature by increasing the cooling capacity of the evaporator by making the heat pump double, but the system should be composed of two, There is a problem that the equipment cost is high because it is necessary to provide an expensive refrigerant and a compressor to withstand.

Third, there is a requirement to limit driving according to defecation and deflation in winter, where demand for drying is high.

The evaporation coil of the heat pump is frosted below the dew point, and the frosting on the evaporation coil causes the compressor to be damaged by the liquid compression, the freezing of the evaporation coil and the freezing of the fins, and the damage of the blowing fan. The periodic defrosting operation is required. Generally, the defrosting operation is performed for 5 to 10 minutes. After the operation of the defrosting operation, the operation is stopped for about 5 minutes in order to prevent the burning of the electric parts by the water vapor, so frequent defrosting stops the production of hot water and increases the energy consumption do.

In conventional heat pumps, defrosting generally applies either reverse cycle operation using a four-way valve or electric heater defrosting.

Inverse cycling defrost is a defrosting method in which the refrigeration cycle is reversely operated. In the defrosting operation, the condensing coil serves as an evaporation coil, and the inside of the dryer in which heat is exchanged is cooled. There are disadvantages that the defrosting can not be performed uniformly, which is a hindrance to the efficiency improvement of the heat pump.

KR 1019900000269 A KR 1020010068616 A JP 201200052744A

The present invention proposes a heat pump dryer capable of initially raising the temperature of a heat pump dryer without using an external heat source but only by operating a refrigeration cycle and is capable of continuously maintaining the internal temperature of the drying chamber at 70 to 80 ° C. And to propose a highly efficient heat pump dryer that prevents the falling of the temperature inside the drying chamber during the defrosting by extending the defrost cycle by delaying the congealing in the evaporating portion.

In order to achieve the above object, the present invention provides a method for heating and drying an object in a drying oven using condensation heat generated in a circulation process of a refrigerant in a heat pump including a compressor, a condenser, an expansion valve, an evaporator, Wherein the expansion valve, the evaporator, the compressor and the connection line are installed outside the drying oven; The drying oven is a closed box type and forms a drying chamber and a heat flow passage therein; And a cold water tank filled with cold water outside, and constitutes a separate cold water circulation cycle in which the cold water of the cold water tank is circulated via the cooling coil of the cooler by the cold water circulation pump, the circulation pipe and the cooler; The condenser and the cooler constitute a closed type heat flow cycle which is circulated to the condenser, the cooler, the drying chamber, and the condenser by being installed together with the blower in the heat flow path in the drying hob; The outline of the condensing section is arranged side by side on the outer side of the evaporation coil of the evaporating section and the bypass line (first bypass line) separate from the above-mentioned expansion valve (first expansion valve) and the on- The refrigerant passing through the outline of the condensing section passes through the first expansion valve or the first bypass line so as to be drawn into the evaporation coil and is connected to the cold water tank by installing a heat exchanger in the connection line between the evaporator and the compressor, And a second bypass line and a second bypass line are provided in parallel between the evaporator and the heat exchanger so that the refrigerant passed through the evaporator is connected to the second expansion valve or the second bypass line, To pass through.

In the present invention, the cooler for moisture condensation inside the dryer and the evaporator constituting the heat pump are separated from each other in the circulation cycle of the refrigerant, so that the heat pump cycle is not limited by the internal temperature of the dryer.

Further, the outline of the condensing section is installed in parallel with the evaporation coil of the evaporator, and the flow of the refrigerant is selected by the expansion valve, the second expansion valve, and the bypass line thereof.

① Initial temperature rise

The first bypass line is closed, the second bypass line is opened, and the cold water circulation cycle and the heat exchange with the cold water are stopped in a state where the compressor-condenser-first expansion valve-evaporator-second bypass line- (Simple passing) - The continuous heat pump cycle is started by the compressor, so the drying high temperature can be raised only by the condensation heat irrespective of the evaporation heat, so that it can be quickly and stably up to the maximum temperature (about 50 ° C.) of the general heat pump dryer without external heat source .

Even when the set temperature is raised to 50 ° C or higher for a higher temperature, the heat remaining in the refrigerant is absorbed by the evaporating portion before being drawn into the expansion valve due to the condensed portion outline and the evaporation coil structure arranged side by side. It maintains the efficiency of the valve and the evaporator. It can raise the internal temperature up to about 80 ℃ which is relatively high temperature, and it can maintain the high temperature even in the drying operation.

② Drying operation

The first bypass line is opened and the second expansion valve is operated and the compressor-condensing section-first bypass line-evaporation coil (simple passing) -compression-cooling section Expansion valve - Heat Exchanger (Heat Exchanger) - A continuous heat pump cycle is started by the compressor. The cold water circulation cycle is activated, and the drying by heating in the drying oven and the moisture removal by condensation are continuously performed.

Even when the internal temperature of the drying compartment is maintained at a relatively high temperature (80 ° C), the compressor inlet refrigerant maintains an appropriate temperature of 10 ° C or less through heat exchange with the cooling water which maintains approximately 10 ° C. Thereby enabling high-temperature continuous operation in a stable state.

In the drying operation, the fan constituting the evaporation portion can reduce the power consumption by stopping the operation in the normal operation state except for the operation of increasing the drying internal temperature, absorbing the heat remaining after the condensation and reusing it, Can be operated. When the room temperature reaches the set temperature during the drying operation, the fan of the condenser in the drying compartment is stopped and the room temperature at which the set temperature is reached can be maintained.

③ Defrosting operation

The outline of the condensing section is installed in parallel with the evaporation coil of the evaporator, so that the frost phase can be delayed during the rising temperature operation of the winter season. In the defrosting operation, the drying high condenser controls the capacity of the condensation fan, The first bypass line opening and the second expansion valve are temporarily switched to the system using the evaporation cold heat, and the drying high condensing part functions as it is with the heater, so that the heating operation is continued, It is possible to solve the problem of the energy efficiency reduction due to the drop in the internal temperature during the defrosting.

BRIEF DESCRIPTION OF THE DRAWINGS Fig.
FIG. 2 is a graph showing the relationship between the temperature-
Fig. 3 is a view showing the defrosting cycle
Fig. 4 is a graph showing the drying cycle

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Fig. 1 shows a basic configuration of the present invention. The present invention relates to a heat pump 10 comprising a compressor 11, a condenser 12, an expansion valve 13, an evaporator 14 and a compressor 11, A heat pump dryer for heating and drying an object in the drying compartment 20 using condensation heat generated in a refrigerant circulation process of the evaporator 14 and condensing and removing heat recovery and high humidity using the cold heat generated in the evaporator 14, (13) - evaporator (14) - compressor (11) and its connecting line are installed outside the drying oven; The drying oven 20 is a closed box type and forms a drying chamber 21 and a heat flow passage 22 therein; And a cold water tank 31 in which cold water is filled in the outside of the dryer and the cold water in the cold water tank is circulated through the cooling coil of the cooler by the cold water circulation pump 32, the circulation pipe 33 and the cooler 34, Constituting a circulation cycle (30); The condenser 12 and the cooler 34 are installed together with the blower 41 in the heat flow path in the drying compartment so that the condenser 12 and the cooler 34 are connected to the drying chamber 21 and the condenser 12 Constitute a closed closed heat flow cycle (40); The outline 121 of the condensing section 12 is disposed in line with the outer periphery of the evaporation coil 141 of the evaporation section 14 and the expansion valve (first expansion valve) 13 and the expansion valve A separate bypass line (first bypass line) 16 and its on / off valve 161 are provided in parallel so that the refrigerant flowing through the outline of the condenser can flow through the first expansion valve 13 or the first bypass line 16, And is connected to the cold water tank 31 through a heat exchanger 17 installed in the connecting line 142 between the evaporator 14 and the compressor 11 50, the second expansion valve 18, the second bypass line 19 and the on-off valve 191 are provided in parallel between the evaporator and the heat exchanger so that the refrigerant passed through the evaporator So that the second bypass line or the second bypass line passes through the second expansion valve or the second bypass line.

The heat pump 10 of the present invention includes a compressor 11 for compressing refrigerant gas, a condenser 12 installed in the drying compartment to heat the interior of the compartment, an expansion valve 13, an evaporator 14, A first expansion valve 13, a second expansion valve 18, a heat exchanger 17, a first bypass line 16, and a second bypass line 19 that selectively operate or pass the refrigerant simply .

The condensing section 12 is installed in the dry high-temperature heat-transfer passage 22, and the other elements are installed in a package or a separate space in a dry space or in a casing.

The compressor (11) to which the present invention is applied is a general compressor which is generally applied to a refrigerator, and it is not necessary to use a high temperature compressor even in high temperature maintenance performance.

The evaporator 14 includes a evaporator coil 141 and a fin (not shown), and has an outline 121 of the condenser 12 disposed in parallel with the outer periphery of the evaporator coil.

The evaporator is provided outside the drying oven and differs from the conventional heat pump oven by providing cooling air to the cooler 34 by heat exchange with cold water. That is, the evaporator is installed outside the drying oven and indirectly provided to the cooler by heat exchange, so that the evaporator is not directly affected by the inside temperature of the dryer, and the cooling water is buffered.

In the present invention, the heat pump includes a first expansion valve and a second expansion valve, and each of the expansion valves is configured with a bypass line and its on / off valve so that when either the first or second expansion valve is actuated And the other has a structure in which the function is stopped by opening the bypass line.

The heat exchanger 17 is installed for the purpose of heat exchange with the cold water of the cold water tank at the compressor inlet stage of the refrigerant, performs the evaporator function during the normal drying operation and the defrosting operation as described later, And performs the function of the refrigerant flow tube without performing the operation.

According to the structure of the heat pump, the function of the evaporator is determined by the movable expansion valve, and the movable expansion valve is determined by opening and closing the bypass line.

That is, when the first bypass line is closed, the high-pressure liquid refrigerant expands through the first expansion valve 13 to perform the evaporation function in the evaporator 14, and when the first bypass line is opened, The liquid refrigerant passes through the first bypass line so that the function of the first expansion valve 13 is stopped and the evaporation coil becomes an extension of the outline 121 of the condensation section 12. [

The second bypass line and the second expansion valve operate in opposition to the first bypass line and the first expansion valve so that the high pressure liquid refrigerant that has passed through the first bypass line is expanded by the second expansion valve, The function is performed in the heat exchanger 17.

In the present invention, the drying oven 20 is constructed of a concrete structure constructed in a box shape or having a heat insulating performance by using a polyurethane panel having excellent heat insulation performance, and a drying object is placed in the interior space, A drying chamber 21 is provided in the upper space and a heat flow passage 22 is formed in the upper space so as to be partitioned by the partition wall so that air in the drying chamber is circulated through the heat flow passage when the heat pump is operated . In addition, an inlet and an outlet are provided so that the object to be dried can be supplied and received, and a ventilation hole necessary for ventilation can be provided. The ventilation hole is combined with the heat flow passage so that the closed heat transfer passage can be used in an open form Can be configured.

The heat flow passage is provided with a blower 41 to constitute a closed type heat flow cycle 40 configured to circulate to the condenser 12 - the cooler 34 - the drying chamber 21.

The cold water circulation cycle 30 comprises a cold water tank 31 capable of storing a predetermined amount of water, a cold water circulation pump 32 for circulating water in the cold water tank to the cooler 34, and a circulation pipe 33 The cold water in the cold water tank circulates via the cooler.

The capacity of the cold water tank (31) can be increased or decreased in proportion to the capacity of the heat pump. The capacity of the cold water tank (31) is controlled so as to maintain a temperature of 5 to 10 ° C during normal operation. And a water supply device and a drain valve are installed so as to maintain a constant water level, and an electric heater can be installed so as to cope with a cold weather.

And a drain pipe 35 for collecting and discharging condensed water is installed in the lower part of the cooler 34. [

The heat exchange cycle 50 is constituted by a heat exchange pipe 51 and a circulation pump 52 for connecting the heat exchanger 17 and the cold water tank 31 so as to absorb the cold generated by the heat pump into the cooling water of the cold water tank.

The cold water is cooled by receiving the cold heat from the heat pump, while the heat is absorbed from the cooler installed inside the dry furnace to maintain the thermal equilibrium at all times and maintain the temperature of 5 to 10 degrees during the operation of the system.

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The operation cycle of the present invention according to the above configuration can be explained with reference to Figs. 2 to 4. The control of the operation cycle is added to the basic control of the heat pump to control the heat flow cycle, the heat exchange cycle, the first and second expansion valves Various operation modes can be applied, which are divided into an initial temperature rising operation cycle, a defrosting operation cycle, and a drying operation cycle by control.

① Initial temperature rising operation cycle

The initial temperature raising operation cycle is a function performed by an external heat source in a conventional heat pump dryer. The present invention is a technique for raising the internal temperature of a drying furnace by operating a heat pump without using an external heat source.

2, the first bypass line 16 is closed, the second bypass line 19 is opened, the heat flow cycle is activated, the cold water circulation cycle 30 and the heat exchange cycle 50 are activated, In this stop state, the heat pump is operated.

The refrigerant is heated through the compressor 11 and the condenser 12 to heat up the interior of the drying compartment and is vaporized via the first expansion valve 13 and the evaporator 14. The vaporized refrigerant flows through the second bypass line 19) - Repeatedly passing through the heat exchanger (17) until the circulation cycle entering the compressor reaches the drying set internal temperature.

On the other hand, when the internal temperature is set at 50 DEG C or higher, the refrigerant temperature and the high internal temperature difference introduced into the condensing portion are not sufficiently large, so that heat is absorbed by the condensing portion but is in an overheated state. And the refrigerant in an overheated state is heat-exchanged with the evaporation coil while passing through the condensation part outline 121 installed side by side with the evaporation coil. When the first expansion valve is drawn in, the superheated degree is dissipated, Vaporization occurs normally.

 The dry internal temperature is raised only by the condensation heat, and the evaporation heat is released to the outside from the evaporation part, and a part of the condensation heat is absorbed through the refrigerant to be recycled.

Accordingly, the drying temperature can be increased only by the condensation heat without being influenced by the evaporation heat, so that it can be quickly and stably increased to the maximum temperature (about 50 ° C) of the general heat pump dryer without an external heat source.

The temperature of the refrigerant applied to the expansion valve is appropriately maintained even when the high-temperature refrigerant is discharged from the condensing portion by heat exchange with the condensing portion outline and the evaporation coil, so that the temperature inside the dryer is relatively high (up to 80 ° C) The temperature rise time can be shortened, and the energy efficiency can be improved.

Further, it is possible to delay the conception of the evaporating coil at the time of operation in the winter season, and accordingly, the defrosting period becomes longer, thereby enabling efficient operation.

② Defrosting operation

The defrosting operation is carried out in order to remove the evaporation coil implantation at the initial warming up in winter.

3, the first bypass line 16 is opened and the second bypass line 19 is closed, so that the first expansion valve does not operate and the second expansion valve 18 operates And the heat flow cycle, the cold water circulation cycle and the heat exchange cycle are normally operated.

The refrigerant heats the interior of the drying compartment through the compressor 11 and the condenser 12 and is expanded at the second expansion valve 18 via the first bypass line 16 and the evaporation coil, 17, the refrigerant is evaporated by the heat exchange with the cold water of the cold water tank and is applied to the compressor (11), and defrosting is performed by the heat while the hot refrigerant discharged from the condenser passes through the evaporation coil.

In the present invention, the condensation part outline is installed in parallel with the evaporation coil of the evaporator, so that the conception is delayed even in the winter season. In the defrosting operation, the drying high condensation part functions as it is with the heater, The problem of reduction in energy efficiency due to temperature drop in the furnace can be solved.

 ③ Drying operation

The drying operation according to the present invention is performed in such a manner that the heat exchanger performs the evaporator function while the evaporator is stopped.

4, the first bypass line 16 is opened and the second bypass line 19 is closed, so that the first expansion valve does not operate and the second expansion valve 18 operates, The heat flow cycle, the cold water circulation cycle, and the heat exchange cycle are normally operated.

The refrigerant heats the interior of the drying compartment through the compressor 11 and the condenser 12 and is expanded at the second expansion valve 18 via the first bypass line 16 and the evaporation coil, 17) by the heat exchange with the cold water of the cold water tank and applied to the compressor (11).

Therefore, the evaporation coil of the evaporation section 14 acts as an extension of the condensation section outline, and the heat exchanger 17 functions as an evaporation section to cool water in the cold water tank.

The water in the cold water tank is supplied to the cooler in the drying oven by the operation of the cold water circulation cycle to condense moisture generated during the drying process and discharge the condensed water to the outside of the drying oven through the drain pipe (35).

Water in the cold water tank is heated by the operation of the cold water circulation cycle, and mixed with water cooled by heat exchange to maintain a temperature of 5 to 10 ° C.

The drying operation of the present invention can maintain the internal temperature up to 80 캜 and dry various objects, and most of the heat energy is recovered and recycled, thereby enabling high efficiency operation.

According to the present invention, the drying internal heat flow and the evaporation portion are indirectly heat-exchanged by the cooling water, and the cooling water of the cooling water tank stably maintains the cooling load of the evaporation portion, so that the internal temperature of the drying oven can be maintained at a relatively high temperature.

In addition, since the drying high internal thermal circulation is configured as a closed type, it is not affected by the external temperature and humidity, and the waste heat recovering rate can be improved, and the total ventilation amount passes through the cooler, , A general heat pump system is applied to constitute a dryer and high temperature continuous operation can be performed by a single cycle, so that it can be economically configured compared to a conventional high temperature compressor and a high temperature dedicated refrigerant or a heat pump having two stages.

10: Heat pump
11: compressor 12: condenser 121: outline
13: expansion valve 14: evaporator 141: evaporation coil
142: connection line
16: first bypass line 161: opening / closing valve
17: heat exchanger 18: second expansion valve 19: second bypass line
191: Gaeppe valve
20: Drying column
21: drying chamber 22: heat flow passage
30: Cold water circulation cycle
31: cold water tank 32: cold water circulation pump 33: circulation tube 34: cooler
35: Water pipe
40: Heat flow cycle
41: blower
50: heat exchange cycle 51: heat exchange tube 52: circulation pump

Claims (1)

The heat of condensation generated in the circulation process of the refrigerant of the heat pump 10 including the compressor 11, the condenser 12, the expansion valve 13, the evaporator 14, (14), a compressor (11), and an evaporator (12), the object being heated and dried, and heat recovery and high humidity being condensed and removed by using the cold heat generated in the evaporator (14) The connection line is installed on the outside of the dryer; The drying oven 20 is a closed box type and forms a drying chamber 21 and a heat flow passage 22 therein; And a cold water tank 31 in which cold water is filled in the outside of the dryer and the cold water in the cold water tank is circulated through the cooling coil of the cooler by the cold water circulation pump 32, the circulation pipe 33 and the cooler 34, Constituting a circulation cycle (30); The condenser 12 and the cooler 34 are installed together with the blower 41 in the heat flow path in the drying compartment so that the condenser 12 and the cooler 34 are connected to the drying chamber 21 and the condenser 12 Constitute a closed closed heat flow cycle (40); The outline 121 of the condensing section 12 is disposed in line with the outer periphery of the evaporation coil 141 of the evaporation section 14 and the expansion valve (first expansion valve) 13 and the expansion valve A separate bypass line (first bypass line) 16 and its on / off valve 161 are provided in parallel so that the refrigerant flowing through the outline of the condenser can flow through the first expansion valve 13 or the first bypass line 16, And is connected to the cold water tank 31 through a heat exchanger 17 installed in the connecting line 142 between the evaporator 14 and the compressor 11 50, the second expansion valve 18, the second bypass line 19 and the on-off valve 191 are provided in parallel between the evaporator and the heat exchanger so that the refrigerant passed through the evaporator Is configured to selectively pass through the second expansion valve or the second bypass line.

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