KR101221586B1 - Low-energy type drying method using waste heat - Google Patents

Abstract

The present invention relates to a low-energy type drying method utilizing waste heat that is used as a heat source of a drying apparatus by recovering heat generated from a heat pump. The present invention relates to a high temperature heat exchanger that contacts and heat exchanges a condenser of a heat pump, and an evaporator of a heat pump. A drying method using a drying apparatus having a control panel capable of selectively supplying hot air, cold air, and dehumidified hot air in a drying chamber, including a low temperature heat exchanger that contacts and heat exchanges, the method comprising: placing a dried product in a dry drying chamber; Inputting type and weight information of the article to be dried; Selecting a drying method for the article to be dried; And selectively supplying warm air, cold air, and dehumidified warm air into the drying chamber according to the selected drying method, and drying the film for a predetermined time.

Description

Low-energy type drying method using waste heat

The present invention relates to a low energy type drying method utilizing waste heat, and more particularly, to a low energy type drying method utilizing waste heat used as a heat source for drying by recovering heat generated from a heat pump.

In the case of rapidly drying large quantities of agricultural products or aquatic products, a drying apparatus using hot air with low humidity is used. In the case of such a drying apparatus, an electric heater is generally used as a heat source.

Therefore, as the scale is increased and the amount of drying treatment is increased, the amount of electric energy consumed is considerable, which can only be included in the price of the dried product, which adversely affects the price competitiveness of the dried product. In addition, since the general consumer needs to spend more money in order to purchase a dry product, there is a problem that the consumption amount of the domestic dry product is reduced.

An object of the present invention devised to solve the above problems is to provide a low-energy type drying method utilizing waste heat that is used as a heat source for drying by recovering waste heat.

The present invention uses waste heat generated in the condenser of the heat pump in order to achieve the above object.

The biggest feature of heat pump technology is that it can supply more energy in the form of thermal energy than the energy required for driving, which makes rational use of energy when using heat pump.

The basic heat pump system consists of a compressor, a condenser, an expansion device, and an evaporator. When a low-temperature, low-pressure gaseous refrigerant is compressed into a high-pressure gas at a temperature higher than the temperature of the atmosphere (or indoor air), it is heated to the atmosphere (or indoor air). In this case, the heat pump uses heat energy to radiate heat. Therefore, the heat pump absorbs heat from low temperature heat sources such as geothermal heat, outside air, low temperature water, and wells, and generates cold air or hot air and discharges it to a place where cold heat or heat is required, thereby enabling efficient use of energy. As such, driving energy is required to produce cold or warm heat from a low temperature heat source, and a compressor is generally used. Most commonly used as driving energy of the compressor is electrical energy used to drive a compressor for compressing a refrigerant of a working fluid of a heat pump system.

Heat dissipation in the heat pump occurs in the condenser, and at the same time, the working fluid refrigerant is cooled to become a high pressure liquid. When the pressure is reduced by using an expansion device such as an expansion valve or a capillary tube, the temperature of the coolant drops rapidly, and at this time, the coolant becomes a low temperature, low pressure saturated state refrigerant. The refrigerant in low temperature can absorb heat from the outside, so when heat is absorbed from the atmosphere (or heat source) using an evaporator, it becomes a gas of low temperature and low pressure, and when it is sent back to the compressor, the heat absorbed by the evaporator is radiated to the condenser as a result. To achieve a heat pump cycle.

Therefore, when heat is required, the heat of the condenser is to be obtained from the heat pump, but when cold heat is required, the heat of the condenser is discarded heat.

In the present invention, the heat of the condenser or the evaporator thus discarded is intended to be used as a heat source of the drying apparatus.

The present invention includes a high temperature heat exchanger for heat exchange in contact with a condenser of a heat pump, and a low temperature heat exchanger for heat exchange in contact with an evaporator of a heat pump. A drying method using a drying apparatus having a step, the method comprising: placing a product to be dried in a mall drying chamber; Inputting type and weight information of the article to be dried; Selecting a drying method for the article to be dried; And selectively supplying warm air, cold air, and dehumidified warm air into the drying chamber according to the selected drying method, and drying the film for a predetermined time.

The selection of the drying method may be selected from data previously input by the control panel on the basis of the type and weight of the article to be dried.

In the case where the selected drying method is constant drying, hot air and dehumidified hot air are selectively supplied into the drying chamber to be dried at a target temperature and a target humidity for a predetermined time, and then subjected to reduced drying at a temperature lower than the target temperature. Should be.

In addition, when the selected drying method is a rate reduction drying, it is characterized in that the drying air for a predetermined time at a target temperature and the target humidity by selectively supplying the warm air and dehumidified hot air in the drying chamber.

In addition, when the selected drying method is a low temperature drying, by selectively supplying cold air and dehumidified warm air in the drying chamber, it is characterized by drying for a predetermined time at the target temperature and target humidity.

In particular, the selection of a fixed time of drying is characterized in that it is determined by checking the weight change of the dried product.

The drying apparatus for implementing such a drying method, the drying chamber having a drying space therein; An intake port and an air supply port formed on an inner wall of the drying chamber; A high temperature heat exchanger contacting the condenser of the heat pump for heat exchange; A low temperature heat exchanger contacting the evaporator of the heat pump for heat exchange; An intake multi-channel valve connected to the intake port and selectively connected to an input side of the high temperature heat exchanger and an input side of the low temperature heat exchanger; A high temperature blower connected to the output side of the high temperature heat exchanger; A low temperature blower connected to the output side of the low temperature heat exchanger; A high temperature discharge multifunction valve connected to the high temperature blower; A low temperature discharge multipurpose valve connected to the low temperature blower; And an air supply valve configured to be selectively connected to the hot discharge valve and the cold discharge valve, wherein the cold discharge valve is connected to an input side of the high temperature heat exchanger, and the hot discharge valve is connected to the air supply port. Connected.

A temperature sensor and a humidity sensor are installed in the drying chamber, and the temperature sensor and the humidity sensor are electrically connected to a control panel, and the control panel is the high temperature blower, the low temperature blower, the intake multi-function valve, the air supply multi-function valve, and the It is characterized in that for controlling the low temperature discharge multi-function valve, and the high temperature discharge multi-function valve.

In addition, the drying chamber is provided with a cradle for placing a shelf on which the object is placed, a load sensor is installed on the cradle, the load sensor is characterized in that it is electrically connected to the control panel.

In addition, the front of the air supply port is characterized in that the electric heater for heating the wind supplied through the air supply port is installed.

In addition, at least one infrared lamp is installed in the drying chamber.

In addition, the output side of the low-temperature heat exchanger is characterized in that the water removal filter for removing water.

Through the present invention, it is possible to replace all or part of the energy required for the drying apparatus from electrical energy by recovering and reusing heat that is discarded in the condenser of the heat pump.

Therefore, since the amount of electrical energy required for the drying apparatus is reduced, the maintenance cost of the drying apparatus is reduced, which in turn can greatly contribute to lowering the price of the drying product. Therefore, the production of inexpensive dry goods can not only increase consumption by increasing consumer's desire to consume, but also contribute to the common economy.

In addition, it is possible to implement both high temperature drying by hot air and low temperature drying by cold air by one drying apparatus through the present invention. In particular, by using a temperature sensor and a humidity sensor it is possible to perform the constant drying and the reduced rate drying according to the characteristics of the product to be dried.

1 is a perspective view of a drying apparatus for implementing a drying method of the present invention.
2 is a block diagram showing the configuration of the drying apparatus of FIG.
3 is a flowchart of a drying method of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In adding reference numerals to components of the following drawings, it is determined that the same components have the same reference numerals as much as possible even if displayed on different drawings, and it is determined that they may unnecessarily obscure the subject matter of the present invention. Detailed descriptions of well-known functions and configurations will be omitted.

First, a drying apparatus 100 capable of implementing the drying method of the present invention will be described with reference to FIGS. 1 and 2.

Drying apparatus 100 according to an embodiment of the present invention is composed of a drying chamber 102, and a dry gas supply unit coupled to a heat pump to supply hot air and cold air to the drying chamber 102.

The drying chamber 102 is a closed structure having a drying space 104 therein, as shown in Figure 1, the wall is preferably filled with a heat insulating material for maintaining the temperature.

One side of the drying chamber 102 is formed with a door 132 for the user to enter and exit, the outside of the drying chamber 102 to display the environment in the drying chamber 102, the information required by the user The control panel 130 is installed to control all the functions of the drying chamber 102.

The interior of the drying chamber 102 is formed with a cradle 126 that can mount the shelf 128 on which the object to be dried. In addition, the shelf 128 is preferably formed with a plurality of through-holes for the ventilation. In addition, the shelf 128 may have a grille shape.

The cradle 126 may be equipped with a load sensor (not shown) such as a load cell to calculate the moisture content of the dry matter by measuring the weight of the dry matter.

In addition, one side wall of the drying chamber 102 is provided with an air supply port for supplying warm air or cold air for drying air, and an intake port for sucking air in the drying chamber 102 for reheating and dehumidifying. . Preferably, the air supply port is disposed below the air intake port so that the air flow in the drying chamber 102 moves up and down. In addition, the air supply ports 120 and 122 and the air intake fans 116 and 118 may be installed in the air supply ports and the air intake ports, respectively, to assist the blowing.

In addition, an infrared lamp 124 is installed on the ceiling or the sidewall of the drying chamber 102 to assist drying through infrared light.

In addition, a temperature sensor 112 and a humidity sensor 114 are installed inside the drying chamber 102 so that the temperature and humidity in the drying chamber 102 can be measured.

In addition, reference numeral 110 indicated in FIG. 1 indicates an installation box in which components such as a valve are disposed.

Next, the said dry gas supply part is demonstrated using FIG. The dry gas supply unit is basically integrally coupled to a heat pump including a condenser 134, a compressor 136, an evaporator 138, and an expansion valve 140. The dry gas supply unit includes a high temperature heat exchanger 142 capable of heat exchange with the condenser 134 and a low temperature heat exchanger 144 capable of heat exchanging with the evaporator 138 to use a heat source of the heat pump. Since the high temperature heat exchanger 142 and the low temperature heat exchanger 144 are used to heat or cool air, air is used as a heat exchange medium.

The high temperature heat exchanger 142 is selectively connected to the low temperature heat exchanger 144 through the intake fans 116 and 118 and the intake coffee valve 154. That is, the intake coffee valve 154 supplies the air in the drying chamber 102 to either one of the high temperature heat exchanger 142 and the low temperature heat exchanger 144 by the signal of the control panel 130. .

In addition to the air in the drying chamber 102, the high temperature heat exchanger 142 may be supplied with air received from the air, the atmosphere, or other heat source supplied from the low temperature heat exchanger 144. The connection between the output side of the low temperature heat exchanger 144 and the input side of the high temperature heat exchanger 142 will be described again below.

The high temperature heat exchanger 142 is connected to the high temperature suction valve 148 to suck air for the release of heat from the atmosphere or other heat source. In addition, a high temperature blower 150 for forced transfer of air is installed at the output side of the high temperature heat exchanger 142, and a high temperature discharge multi-way valve 152 is connected to the output side of the high temperature blower 150.

The high temperature exhaust bar valve 152 is selectively used with the air supply port valve 156 to supply hot air to the drying chamber 102 and the high temperature discharge port to use heat for other purposes or to discharge to the atmosphere or other heat source. Is connected.

The low temperature heat exchanger 144 may be supplied with air received from the atmosphere or other heat source in addition to the air in the drying chamber 102. Thus, the low temperature heat exchanger 144 is connected to the low temperature suction valve 164 to suck air for absorption of heat from the atmosphere or other heat sources.

In addition, a low-temperature blower 162 for forced movement of air is installed at the output side of the low-temperature heat exchanger 144, and at the front end or the rear end of the low-temperature blower 162 to remove moisture from the air bubbled air due to cooling. The water removal filter 160 is disposed.

In addition, a low temperature discharge cafe valve 158 is installed to change a path of the air passing through the low temperature blower 162 and the water removal filter 160. The low temperature discharge diverter valve 158 is selectively connected to the high temperature heat exchanger 142, a low temperature discharge port for discharge to the atmosphere or another heat source, and the air supply multiplier valve 156. That is, the air cooled from the low temperature heat exchanger 144 may be utilized for other purposes, heated in the high temperature heat exchanger 142 after dehumidification during drying, or directly supplied with an air supply port of the drying chamber 102 when cold air is required. Connected.

The air supply valve 156 is selectively connected between the low temperature discharge valve 158 and the high temperature discharge valve 152 to supply air into the drying chamber 102. At this time, in order to prepare for the case where the amount of heat absorbed by the high temperature heat exchanger 142 is insufficient, the electric heater 146 in front of the air supply port, that is, between the air supply fan (120, 122) and the air supply multi-way valve 156. Can be installed.

Drying apparatus 100 according to an embodiment of the present invention is basically configured as described above. Hereinafter, a drying method using the drying apparatus 100 will be described.

By the drying apparatus 100, it is possible to perform low temperature drying by constant drying, reduction rate drying, and cold wind.

Constant drying is called constant drying because the drying amount per unit time is almost constant until the water content decreases to some extent when drying the food, and the drying speed during this period is very large. After that, it moves to the rate reduction drying where the drying speed decreases over time. The amount of water in moving from constant drying to deceleration drying is called the marginal moisture content.

The marginal water content, which represents the boundary between the rate drying and the rate reduction drying, is almost constant if the same kind of material is used and the drying conditions are the same. In general, when drying occurs rapidly and the surface evaporation is vigorous, internal diffusion is also promoted accordingly. However, as the water content of the material decreases, internal diffusion also becomes more difficult. Therefore, the higher the drying speed, the faster the time to reach the limit of internal diffusion and the greater the critical moisture content.

The constant drying period is a period during which drying continues while the surface of the building is covered with free water. All the heat supplied from outside is used as latent heat of evaporation. Therefore, the drying rate is governed by the surface evaporation rate, but the influence of the internal diffusion rate of moisture is small. The first stage of deceleration drying generally has a short duration, and especially when the drying rate is high, this period does not appear, and sometimes it moves directly from the constant drying to the second stage of deceleration drying. This period is a process in which the water content slopes from the inside of the food to the surface, and the influence of the internal diffusion rate gradually increases. The second stage of reduction rate drying is a process in which the effective evaporation surface area decreases due to an increase in the dry portion of the surface of the building, and the drying speed decreases rapidly due to drying shrinkage and surface hardening. During this period, the resistance of internal diffusion of moisture increases, so that the water diffuses to a liquid state somewhere in the material. More than that, it is difficult to move, and from there, it evaporates and diffuses the fine pores into the vapor state and moves to the surface. At this point, some of the bound water is also removed and the surface of the building is almost in equilibrium.

In order to operate the drying apparatus 100, first, the shelf 128 is mounted in the drying apparatus 100 by mounting a dried object. On the shelf 128, the dry items are laid out to facilitate drying and are arranged at regular intervals.

Next, the user selects a drying method among the constant drying, the reduction rate drying, the reduction rate drying, and the low temperature drying according to the type of the dry material. The control panel 130 may store a drying method in accordance with the type of the dry object in advance to present a preferred drying method only by the user to input the type of the dry object.

In the constant moisture drying, which is generally high moisture, the target temperature in the drying chamber 102 is set to 55 to 65 ° C., and the reduction rate drying is 45 to 50 ° C. In addition, the target humidity in the drying chamber 102 is determined in consideration of the equilibrium moisture content according to the type and size of the object to be dried. This is also preferable to be able to determine by inputting the data in advance to the control panel 130.

Through this process, drying is started.

In the case of constant drying, first, the temperature and humidity in the drying chamber 102 are reached as quickly as possible to the target temperature. The flow of air for the temperature rise in the drying apparatus 100, the intake fan (116, 118), the intake bag valve 154, the high temperature heat exchanger (142), the high temperature blower (150), the hot exhaust valve 152, the air supply valve 156, and the air supply fans 120 and 122. In particular, for the rapid temperature rise, the infrared lamp 124 as well as the electric heater 146 may be simultaneously operated.

And, the flow of air for humidity control in the drying apparatus 100, the intake fan (116, 118), the intake coffee room valve 154, the low temperature heat exchanger (144), the low temperature blower (162), the water removal The filter 160, the low temperature discharge multi-valve valve 158, the high temperature heat exchanger 142, the high temperature blower 150, the high temperature discharge multi-function valve 152, the air supply multi-function valve 156, and the air supply fan In the order of (120,122).

Therefore, the air inlet is passed through the high temperature heat exchanger 142 immediately after the intake, and the high temperature heat exchanger 142 after passing through the low temperature heat exchanger 144 is selected by the intake multi-way valve 154. Temperature control and humidity control are available.

Since relative humidity changes with temperature, it is preferable to give priority to temperature control over humidity control.

In the case of the first rate reduction drying, only the target temperature is different from the rate drying, but the air flow is the same. However, in the case of deceleration drying after constant drying, the temperature inside the drying chamber 102 should be lowered. In this case, for the gentle temperature gradient, the temperature of the air supplied into the drying chamber 102 may be lowered slowly by using the air flow of the moisture control.

For a sudden temperature gradient, it may be performed by supplying cold air directly into the drying chamber 102. Air flow for this purpose, the intake fan (116, 118), the intake bag valve 154, the low temperature heat exchanger (144), the low temperature blower (162), the water removal filter (160), the low temperature discharge bag valve ( 158), the air supply valve 156, and the air supply fans 120 and 122. In this case, in order to prevent the drying quality from being lowered too much, the electric heater 146 may be supplied by raising a predetermined level of temperature.

Next, for low temperature drying, cold air is directly supplied to the drying chamber 102. Generally, the temperature is adjusted to 15 ° C to 35 ° C and the relative humidity is about 20% to circulate and dry. Low temperature drying is caused by the difference between the vapor pressure of cold wind and the vapor pressure of raw materials. In this case, air flows through the intake fans 116 and 118, the intake bag valve 154, the low temperature heat exchanger 144, the low temperature blower 162, the water removal filter 160, and the low temperature discharge bag valve ( 158), the air supply valve 156, and the air supply fans 120 and 122. In this case, in order to prevent the drying quality from being lowered too much, the electric heater 146 may be supplied by raising a predetermined level of temperature. In addition, the air passing through the high temperature heat exchanger 142 may be supplied for a predetermined time instead of the electric heater 146.

In the same process as described above, it is possible to perform both constant drying, reduced drying, and low temperature drying in one drying apparatus 100.

And, in order to end the drying in the rate drying, the rate reduction drying, and low temperature drying, or to move from the rate drying to the rate reduction drying, the drying time should be appropriately adjusted. In a simple method, the user may input the drying time in advance in the control panel 130 or set the drying time in consideration of the type and size of the object to be dried in the information previously input to the control panel 130.

It is also possible to check the water content of the dry matter in a more aggressive manner. That is, when the shelf 128 is placed on the cradle 126, after zeroing the load sensor included in the cradle 126, the dry object is placed. Therefore, the weight of the object is measured by the load sensor, and the control panel 130 may calculate the moisture content of the object in consideration of the type of the object.

Therefore, the control panel 130 continuously monitors that the weight of the dried article is reduced when the water is removed through the drying process after the start of drying, and thus the limit moisture content, or the rate reduction drying and the low temperature drying, which are the boundary points between the constant drying and the reduced drying. You can check the target moisture for the end of drying. Therefore, when the critical moisture content or the target moisture content is checked by the control panel 130, it may change from the constant drying to the reduction rate drying or may terminate the drying.

As described above, it has been described with reference to the preferred embodiment of the present invention, but those skilled in the art various modifications and changes of the present invention without departing from the spirit and scope of the present invention described in the claims below I can understand that you can.

100: drying apparatus 102: chamber
104: drying space 110: equipment box
112: temperature sensor 114: humidity sensor
116, 118: intake fan 120, 122: air supply fan
124: infrared lamp 126: holder
128: shelf 130: control panel
132: door 134: condenser
136: compressor 138: evaporator
140: expansion valve 142: high temperature heat exchanger
144: low temperature heat exchanger 146: electric heater
148: high temperature suction valve 150: high temperature blower
152: high temperature exhaust tea room valve 154: intake tea room valve
156: air supply valve 158: low temperature discharge valve
160: water removal filter 162: low temperature blower
165: low temperature suction valve

Claims (12)

A drying apparatus having a control panel capable of selectively supplying warm air, cold air, and dehumidified warm air into the drying chamber, including a high temperature heat exchanger that heats the heat condenser in contact with the heat pump, and a low temperature heat exchanger that heats the heat exchanger in contact with the evaporator of the heat pump. In the drying method used,
Placing the product to be dried in the mall drying chamber;
Inputting type and weight information of the article to be dried;
Selecting a drying method for the article to be dried; And
A low energy type drying method using waste heat comprising selectively supplying hot air, cold air, and dehumidified hot air into the drying chamber according to a selected drying method for drying for a predetermined time.
The method of claim 1, wherein the selection of the drying method is selected from the data previously input by the control panel based on the type and weight of the product to be dried.
The method of claim 1, wherein when the selected drying method is constant drying, the hot air and the dehumidified hot air are selectively supplied into the drying chamber to be dried at a target temperature and a target humidity for a predetermined time, and then reduced again at a temperature lower than the target temperature. Low energy type drying method utilizing waste heat, characterized in that for drying.
The low-energy type using waste heat according to claim 1, wherein when the selected drying method is a deceleration drying method, the hot air and the dehumidified hot air are selectively supplied into the drying chamber and dried at a target temperature and a target humidity for a predetermined time. Drying method.
The low-energy type using waste heat according to claim 1, wherein when the selected drying method is a low temperature drying method, cold air and dehumidified warm air are selectively supplied into the drying chamber and dried at a target temperature and a target humidity for a predetermined time. Drying method.
The low energy type drying method using waste heat according to any one of claims 3 to 5, wherein the selection of a predetermined time of drying is determined by checking a change in weight of the dried product.
The method of claim 1, wherein the drying apparatus,
A drying chamber having a drying space therein;
An intake port and an air supply port formed on an inner wall of the drying chamber;
A high temperature heat exchanger contacting the condenser of the heat pump for heat exchange;
A low temperature heat exchanger contacting the evaporator of the heat pump for heat exchange;
An intake multi-channel valve connected to the intake port and selectively connected to an input side of the high temperature heat exchanger and an input side of the low temperature heat exchanger;
A high temperature blower connected to the output side of the high temperature heat exchanger;
A low temperature blower connected to the output side of the low temperature heat exchanger;
A high temperature discharge multifunction valve connected to the high temperature blower;
A low temperature discharge multipurpose valve connected to the low temperature blower; And
And an air supply valve configured to be selectively connected to the high temperature discharge valve and the low temperature discharge valve.
The low-temperature exhaust coffee valve is connected to the input side of the high temperature heat exchanger, the high-temperature exhaust coffee valve is a low-energy type drying method utilizing waste heat connected to the air supply port.
The method of claim 7, wherein the temperature chamber and the humidity sensor is installed inside the drying chamber, the temperature sensor and the humidity sensor is electrically connected to the control panel, the control panel is the high temperature blower, the low temperature blower, the intake coffee valve, The low energy type drying method using waste heat, characterized in that for controlling the air supply valve, the low temperature discharge room valve, and the high temperature discharge room valve.
The method of claim 7, wherein the drying chamber is provided with a cradle for placing the shelf to be placed, the load sensor is installed in the cradle, the load sensor is characterized in that it is electrically connected to the control panel Low energy drying method using waste heat.
The low energy type drying method using waste heat according to claim 7, wherein an electric heater for heating wind supplied through the air supply port is installed at a front end of the air supply port.
According to claim 7, Low energy type drying method using waste heat, characterized in that one or more infrared lamps are installed inside the drying chamber.
The method of claim 7, wherein the low-temperature drying method using waste heat, characterized in that a water removal filter for removing water is installed on the output side of the low temperature heat exchanger.

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