JP7379552B2 - Air conditioning system for painting equipment - Google Patents

Description

The present invention relates to an air conditioning system for painting equipment.

Painting equipment generally includes equipment such as a paint booth that applies paint to objects to be painted, such as automobile bodies, and a drying oven that dries the paint on the objects that have passed through the coating booth. In such painting equipment, a painting booth air conditioner supplies air whose temperature and humidity have been adjusted into the painting booth to perform painting. Paint booth air conditioners are made up of equipment such as a heating device, a cooling device, a humidifier (washer), and a blower fan. By operating these devices in combination, the conditioned air reaches the target temperature. Control is performed so that the humidity is maintained (for example, see Patent Document 1). By the way, each device used in painting equipment consumes a large amount of energy. However, in recent years there has been an increasing demand for reducing carbon dioxide emissions, and therefore it is desired to reduce energy consumption as much as possible. Under these circumstances, for example, an exhaust gas recycling air conditioning system has been previously proposed in which high-humidity air recycled in a paint booth is dehumidified and reheated using a heat pump, temperature and humidity are adjusted using a paint booth air conditioner, and the air is reused in the paint booth. (For example, see Patent Document 2). In addition, in the paint booth air conditioner of this system, a predetermined position on the psychrometric diagram is set as the target point for the temperature and humidity of the conditioned air, and the outside air taken in is heated, cooled, and humidified as appropriate. The temperature and humidity are controlled to reach the target point.

Patent No. 3993358 Japanese Patent Application Publication No. 2010-119901

However, in the conventional painting equipment mentioned above, measures were taken to save energy required for air conditioning by reusing waste heat within the same equipment, so there is a natural limit to the extent to which energy consumption can be reduced. Ta. On the other hand, when looking at each device in a painting facility, unnecessary heat or cold is still generated, and this is not being used effectively and is being discarded.

The present invention has been made in view of the above-mentioned problems, and its purpose is to provide an air conditioning system for painting equipment that can reduce the energy consumption required for air conditioning by effectively utilizing the exhaust heat of each device in the painting equipment. Our goal is to provide the following.

In order to solve the above problems, the invention described in Means 1 includes a coating booth that applies paint to an object to be coated, and a drying oven that dries the paint on the object that has passed through the coating booth. An air conditioning system for painting equipment, which includes a booth air conditioner that supplies outside air, adjusts its temperature and humidity, and sends the air to the painting booth, and a heat separation system that separates heat from the outside air taken in and discharges cold heat. an exhaust reheating means which heats the exhaust gas from the drying furnace with the heat separated by the heat separation means and returns it to the drying furnace; and temperature and humidity of the cold exhaust gas generated by the heat separation means. , Based on the comparison result with the temperature and humidity of the outside air, the supply temperature and humidity to the booth air conditioner is set by supplying at least one of the cold exhaust gas and the outside air as conditioned air to the booth air conditioner. and an air conditioner control means that performs control to bring the temperature and humidity close to the set temperature and humidity, and the air conditioner control means adjusts the set temperature and humidity based on the set temperature and humidity information, the temperature and humidity information of the outside air, and the temperature and humidity information of the cold exhaust gas. a calculation means for calculating enthalpy, the enthalpy of the outside air, and the enthalpy of the cold exhaust gas; and the setting based on the enthalpy of the set temperature and humidity, and the enthalpy of the outside air and the enthalpy of the cold exhaust air calculated by the calculation means a first comparison means for calculating and comparing an enthalpy difference between the temperature and humidity and the outside air and an enthalpy difference between the set temperature and humidity and the cold exhaust gas; and a predetermined range set in advance with the enthalpy of the set temperature and humidity as a center value. A first step of comparing an upper limit value and a lower limit value of 2 comparison means, and conditioned air selection means for selecting at least one of the outside air and the cold exhaust air as the conditioned air, and the conditioned air selection means is configured such that both the enthalpy of the outside air and the enthalpy of the cold exhaust air are If the condition of belonging to the predetermined range is met, both the outside air and the cold exhaust air are selected as the conditioned air; if the condition is not met, and the set temperature and humidity and the If the enthalpy difference with the outside air is smaller, the outside air is selected as the conditioned air, and if the above conditions are not met and the enthalpy difference between the set temperature and humidity and the cold exhaust air is smaller, the outside air is selected as the conditioned air. The gist of the present invention is an air conditioning system for painting equipment, characterized in that the cold exhaust gas is selected as the conditioned air .
The invention described in Means 2 provides, in Means 1, a cold heat transfer path connected in a flow path to the air supply side of the booth air conditioner to transfer the cold heat exhaust gas generated by the thermal separation means; a cold exhaust intake damper provided at the end of the cold heat transfer path and capable of adjusting the amount of cold exhaust gas taken into the booth air conditioner by adjusting the opening; and an air supply side of the booth air conditioner. The main feature is that the damper is provided with an outside air intake damper that is installed in the damper and can adjust the amount of outside air taken in by adjusting the opening.
In the invention described in Means 3, in Means 2, the air conditioner control means controls to open both the cold and hot exhaust intake damper and the outside air intake damper when the condition is satisfied. , if the above conditions are not met and the enthalpy difference between the set temperature and humidity and the outside air is smaller, control is performed to close the cold and hot exhaust intake damper and open the outside air intake damper. , if the conditions are not met and the enthalpy difference between the set temperature and humidity and the cold exhaust air is smaller, control is performed to open the cold exhaust intake damper and close the outside air intake damper. Its gist is what it does.

Therefore, according to the invention described in Means 1, among the heat and cold heat separated by the thermal separation means of the exhaust gas reheating means, the heat is utilized for reheating the drying furnace through heating the exhaust gas from the drying furnace. On the other hand, the cold heat generated by the heat separation means after heat absorption is discharged without being utilized in the drying oven. The temperature and humidity of this cold exhaust gas is compared with the temperature and humidity of outside air, and if predetermined conditions are met, at least a portion of the cold exhaust gas is supplied to the booth air conditioner as conditioned air. In other words, the cold exhaust gas that was not used in the drying oven and was discarded is effectively used as conditioned air for the painting booth after passing through the booth air conditioner. Therefore, it is possible to reduce the energy consumption required for air conditioning.

Further, according to the above invention, the first comparison means calculates the enthalpy difference between the set temperature and humidity and the outside air, the set temperature and humidity and the cold exhaust, based on the enthalpy of the set temperature and humidity, the enthalpy of the outside air, and the enthalpy of the cold exhaust air calculated by the calculation means. Calculate and compare the enthalpy difference between Based on the comparison result, the conditioned air selection means selects as the conditioned air the one having a smaller enthalpy difference from the set temperature and humidity, that is, the one that requires less energy to approach the set temperature and humidity, from outside air and cold exhaust air. As a result, it becomes possible to reduce energy consumption required for air conditioning.

Further, according to the above invention, when the second comparison means determines that the difference between the enthalpy of the outside air, the enthalpy of the cold exhaust air, and the enthalpy of the set temperature and humidity is relatively small, both the outside air and the cold exhaust air are selected as the conditioned air. Ru. In this case, stable setting temperature and humidity adjustment can be performed.

As described in detail above, according to the invention according to claims 1 to 3, the air conditioning system for painting equipment is capable of effectively utilizing the exhaust heat of each device in the painting equipment to reduce energy consumption required for air conditioning. can be provided.

1 is a schematic diagram for explaining an air conditioning system for painting equipment according to an embodiment of the present invention. FIG. 1 is a schematic plan view showing the layout of painting equipment according to an embodiment. FIG. 1 is a block diagram showing an electrical configuration of an air conditioning system for painting equipment according to an embodiment. The psychrometric diagram for explaining the temperature and humidity control method by the air conditioning system for painting equipment in the embodiment. The psychrometric diagram for explaining the temperature and humidity control method by the air conditioning system for painting equipment in the embodiment. FIG. 3 is a schematic diagram for explaining an air conditioning system for painting equipment according to another embodiment of the present invention.

Hereinafter, an air conditioning system 31 for painting equipment according to an embodiment of the present invention will be described in detail based on FIGS. 1 to 5.

FIG. 1 is a schematic diagram for explaining an air conditioning system 31 for painting equipment, and FIG. 2 is a schematic plan view showing the layout of the painting equipment. The coating equipment of this embodiment includes a coating booth 11, a drying oven 21, and an air conditioning system 31 for the coating equipment (booth air conditioner 41, air conditioner heat pump 51, heat exchanger 61, hot water storage tank 71, and drying oven heat pump 81). It is equipped with

As shown in FIG. 2, the coating booth 11 and drying oven 21 that constitute the coating equipment of this embodiment are arranged on one conveyance line that conveys objects to be coated (for example, automobile bodies). In this conveyance line, the coating booth 11 is arranged on the upstream side, and the drying oven 21 is arranged on the downstream side.

The area where the painting booth 11 is provided is an area for applying paint to objects on the conveyance line. The painting booth 11 includes a painting room, an air supply chamber provided above the painting room for supplying downflow (a fixed direction from above to below) air to the painting room, and an air supply chamber provided below the painting room. It is equipped with an exhaust chamber for exhausting the air inside the painting chamber. In the painting booth 11 of this embodiment, conditioned air discharged from the booth air conditioner 41 is supplied into the painting room in a downflow from the air supply chamber.

In the coating room of the coating booth 11, objects to be coated are coated by spraying paint mist from a coating machine (not shown). At this time, paint mist oversprayed and scattered from the coating machine is discharged from the painting chamber to the exhaust chamber by the downflow of conditioned air acting within the painting chamber. In the exhaust chamber, a dry filter is used to capture paint mist in the air and recover the paint. Moreover, the air exhausted from the exhaust chamber is discharged into the atmosphere by a blower fan.

The area where the drying oven 21 is provided is an area for drying the paint on the object that has passed through the coating booth 11. This drying oven 21 is usually formed in the shape of a tunnel with entrances and exits provided at both ends of the oven body in order to dry and harden the coating film while conveying the object to be coated by a conveyor (see FIG. 1). Inside the drying oven 21, a plurality of drying zones are provided consecutively, for example, along the longitudinal direction of the oven. Each drying zone is provided with a hot air supply port that blows hot air into the furnace, and an exhaust port that discharges hot air from the furnace. Therefore, when the object to be coated passes through the drying oven 21, the paint on the object is dried by being exposed to hot air blown out from the hot air supply port.

As shown in FIG. 1, the booth air conditioner 41 adjusts air taken in from outside the device to a predetermined temperature (for example, around 23° C.) and a predetermined humidity (for example, around 70% RH), and then sends the air to the painting booth 11. It is a device for The booth air conditioner 41 of this embodiment is arranged in parallel to the coating booth 11 in a state immediately adjacent to the coating booth 11 on the conveyance line. This booth air conditioner 41 includes a preheater 42, a washer 43, a cooling coil 44, a reheater 45, and a blower fan 46. Note that the outlet side of the booth air conditioner 41 and the painting booth 11 are connected in terms of a flow path via a conditioned air transfer path 49.

The preheater 42 is a type of temperature control means that adjusts the temperature of the air taken in, and is a heating means that heats the air to raise its temperature. The washer 43 is a type of humidity control means that adjusts the humidity of the air taken in, and is a humidification means that increases the humidity of the air by jetting water to the air that has passed through the preheater 42. The cooling coil 44 is a type of temperature control means that adjusts the temperature of the air taken in, and is a cooling means that cools the air that has passed through the washer 43 to lower the temperature. The reheater 45 is a type of temperature control means that adjusts the temperature of the air taken in, and is a heating means that heats the air that has passed through the cooling coil 44 to raise the temperature. The blower fan 46 is a means for forcefully feeding temperature- and humidity-controlled air (ie, conditioned air) to the coating booth 11 .

As shown in FIG. 2, the air conditioner heat pumps 51 are so-called indirect temperature control type heat pumps, and a plurality of them are arranged near and adjacent to the booth air conditioner 41. Note that the booth air conditioner 41 is located between the paint booth 11 and a heat pump group consisting of a plurality of air conditioner heat pumps 51.

As shown in FIG. 1, the air conditioner heat pump 51 has a refrigerant flow path 52 through which a refrigerant as a heat medium flows. The refrigerant passage 52 is a closed annular passage, and a condenser (heat radiation part), an evaporator (heat absorption part), a compressor, and an expansion valve are installed on the refrigerant passage 52. The condenser is a device that exchanges heat between the refrigerant flow path 52 and the hot air supply path 53. The heat of the refrigerant flowing in the refrigerant flow path 52 is transferred to the circulating water flowing in the hot air supply path 53 to generate hot water. This hot water is supplied to the preheater 42 and reheater 45 via the hot water supply path 53. Note that the circulating water whose temperature has decreased after passing through the preheater 42 and the reheater 45 is returned to the air conditioner heat pump 51 via the hot water return path 54 and heated again. On the other hand, the cold heat of the refrigerant flowing in the refrigerant flow path 52 is transmitted to the circulating water flowing in the cold air supply path 55 to generate cold water. This cold water is supplied to the cooling coil 44 via the cold water supply path 55. Note that the cold water whose temperature has increased after passing through the cooling coil 44 is returned to the air conditioner heat pump 51 via the cold water return path 56 and is cooled again. Note that the air conditioner heat pump 51 can supply either hot water or cold water by switching between them. Switching between the hot water supply path and the cold water supply path through which the circulating water flows is performed by a valve (not shown).

As shown in FIG. 1, in this embodiment, a heat exchanger 61, a hot water storage tank 71, and a drying oven heat pump 81 constitute an exhaust gas reheating means. The drying oven heat pump 81 (thermal separation means) constituting the exhaust gas reheating means separates heat from the taken in outside air and discharges cold heat. This drying oven heat pump 81 is also an indirect temperature control type heat pump, and a plurality of heat pumps are arranged adjacent to each other near the air supply side end of the booth air conditioner 41.

The drying oven heat pump 81 has a refrigerant flow path 82 through which a refrigerant as a heat medium flows. The refrigerant passage 82 is a closed annular passage, and a condenser (heat radiation part), an evaporator (heat absorption part), a compressor, and an expansion valve are installed on the refrigerant passage 82. The condenser is a device that exchanges heat between the refrigerant flow path 82 and the high temperature water supply path 83. The heat of the refrigerant flowing in the refrigerant flow path 82 is transferred to the circulating water flowing in the high temperature water supply path 83 to generate high temperature water. This high-temperature water is supplied to the hot water storage tank 71 via the high-temperature water supply path 83, and heats the water in the hot water storage tank 71 to turn it into hot water. In other words, this hot water storage tank 71 functions as a water damper for alleviating changes in the heated water temperature. Note that the high-temperature water whose temperature has decreased after passing through the hot water storage tank 71 is returned to the drying oven heat pump 81 via the high-temperature water return path 84 and heated again.

On the other hand, the cold heat of the refrigerant flowing in the refrigerant flow path 82 becomes cold exhaust gas and is discharged to the outside of the drying oven heat pump 81 via the cold heat transfer path 86 (see FIG. 2). This cold heat transfer path 86 is connected to the air supply side of the booth air conditioner 41 in a flow path manner. At the end of the cold heat transfer path 86, a cold heat exhaust intake damper (not shown) is provided. By adjusting the opening degree of this cold exhaust intake damper, the amount of cold exhaust taken into the booth air conditioner 41 can be adjusted. Further, an outside air intake damper (not shown) is provided on the air supply side of the booth air conditioner 41. By adjusting the opening degree of this outside air intake damper, the amount of outside air taken in can be adjusted.

The heat exchanger 61 is disposed immediately adjacent to the drying oven 21 in the conveyance line and adjacent to the air supply side end of the booth air conditioner 41. The primary side of the heat exchanger 61 and the drying oven 21 are connected via an exhaust path 62 in terms of a flow path. The secondary side of the heat exchanger 61 and the drying oven 21 are connected via a return path 63 in terms of a flow path. A blower fan 64 is provided on the return path 63. Further, the heat exchanger 61 and the high temperature side of the hot water storage tank 71 are connected via a hot water supply path 72 in terms of a flow path. The heat exchanger 61 and the low temperature side of the hot water storage tank 71 are connected via a hot water return path 73 in terms of a flow path. Therefore, the exhaust gas supplied from the drying furnace 21 to the heat exchanger 61 is heated and then returned to the drying furnace 21 for reuse. That is, the exhaust gas reheating means of this embodiment plays the role of heating the exhaust gas from the drying furnace 21 with the heat separated by the thermal separation means and returning it to the drying furnace 21. Note that the hot water storage tank 71 is arranged between the drying oven heat pump 81 and the heat exchanger 61 near the air supply side end of the booth air conditioner 41.

This painting equipment air conditioning system 31 is provided with sensing means at several locations. Specifically, the booth air conditioner 41 also includes an air conditioner inlet temperature/humidity sensor S1, an air conditioner outlet temperature/humidity sensor S2, and an air conditioner internal temperature sensor S3. The air conditioner inlet temperature/humidity sensor S1 is arranged near the outside air intake in the booth air conditioner 41. The air conditioner outlet side temperature and humidity sensor S2 is arranged on the outlet side of the blower fan 46 through which conditioned air is sent out. The air conditioner internal temperature sensor S3 is arranged upstream of the washer 43. Further, outside the booth air conditioner 41, an outside temperature and humidity sensor S4 is provided. A hot water supply route temperature sensor S5 is arranged on the hot water supply route 53 near each air conditioner heat pump 51, and a cold water supply route temperature sensor S6 is arranged on the cold water supply route 55. Further, a high temperature water supply route temperature sensor S7 is arranged on the high temperature water supply route 83 in the drying oven heat pump 81, and a high temperature water return route temperature sensor S8 is arranged on the high temperature water return route 84. . Furthermore, a heat exchanger secondary side temperature sensor S9 is arranged on the secondary side of the heat exchanger 61. Further, on the cold/heat transfer path 86, a cold/heat exhaust temperature/humidity sensor S10 is provided.

This air conditioning system 31 for painting equipment includes a control device 91 (air conditioner control means) constituted by a well-known computer including a CPU, storage means 91e (ROM, RAM), and the like. As shown in the block diagram of FIG. 3, this control device 91 further includes calculation means 91a, first comparison means 91b, second comparison means 91c, and conditioned air selection means 91d. Control objects (namely, preheater 42, washer 43, cooling coil 44, reheater 45, and blower fan 46) are electrically connected to this control device 91 via respective driver circuits (not shown). Further, each of the above-mentioned sensors S1 to S10 is electrically connected to this control device 91. In the control device 91 configured as described above, the control target in the booth air conditioner 41 is variably controlled based on the measurement results of temperature and humidity output from each sensor S1 to S10. As a result, conditioned air that is adjusted to a predetermined temperature and humidity is generated.

Next, temperature and humidity control performed by the control device 91 will be explained. A storage means 91e constituting the control device 91 stores a program for controlling temperature and humidity, and the CPU reads out the program from the storage means 91e and sequentially executes the program. In addition to this program, the storage means 91e stores data related to a psychrometric chart 101 (a psychrometric chart table) that expresses air condition values in coordinates. Incidentally, the enthalpy increases as it goes to the upper right of the psychrometric diagram 101, and conversely, it decreases as it goes to the lower left.

The control device 91, which is an air conditioner control means, compares the temperature and humidity of the cold exhaust gas generated by the drying furnace heat pump 81, which is a heat separation means, with the temperature and humidity of the outside air. Based on the result, the control device controls the supply temperature and humidity to the booth air conditioner 41 to approach the set temperature and humidity by supplying at least one of the cold exhaust air and the outside air as conditioned air to the booth air conditioner 41. I do. This control will be explained in detail below.

Here, point P1 on the hygrodynamic diagram 101 in FIGS. 4 and 5 indicates the ideal state point (i.e., control target point) of the temperature and humidity of the conditioned air at that point, and the temperature and humidity at this point P1 is defined as the set temperature and humidity. In the humid air diagram 101 of FIG. 4, point P2 indicates the state point P2 of the cold and hot exhaust discharged by the drying furnace heat pump 81, and P3 indicates the state point P3 of the outside air. Note that the enthalpy of cold exhaust gas is expressed as E2, and the enthalpy of outside air is expressed as E3. On the psychrometric diagram 101, a range of a predetermined width is set in advance around the enthalpy E1 of the set temperature and humidity. The upper limit of this range is expressed as E1max, and the lower limit is expressed as E1min. Although the range of the predetermined width is not particularly limited, it is set to ±5 (kJ/kg (DA)) in this embodiment. Therefore, for example, if the enthalpy E1 of the set temperature and humidity is 60, the predetermined width is 10, the upper limit E1max is 55, and the lower limit E1min is 65.

The calculation means 91a (i.e., CPU) in the control device 91 calculates the enthalpy E1 of the set temperature and humidity, based on the set temperature and humidity information obtained by each of the sensors S1 to S10, the temperature and humidity information of the outside air, and the temperature and humidity information of the cold exhaust gas. The enthalpy E3 of outside air and the enthalpy E2 of cold exhaust gas are calculated.

Next, the first comparison means 91b (i.e., CPU) in the control device 91 calculates the enthalpy difference ΔE13 between the set temperature and humidity and the outside air, and the difference between the set temperature and humidity and the cold exhaust gas based on the three calculated enthalpies E1, E2, and E3. The enthalpy difference ΔE12 is calculated and compared with each other. In addition, the second comparison means 91c (i.e., CPU) in the control device 91 compares the upper limit value E1max and lower limit value E1min of a predetermined range set in advance with the enthalpy E1 of the set temperature and humidity as the central value, and the enthalpy E3 and cold heat of the outside air. Compare with exhaust enthalpy E2. Then, it is determined whether both the enthalpy E3 of the outside air and the enthalpy E2 of the cold exhaust gas belong to a predetermined range.

For example, in the state shown in FIG. 4, the enthalpy E3 of outside air and the enthalpy E2 of cold exhaust air are both outside the predetermined range, and the enthalpy E3 of outside air is larger than the enthalpy E2 of cold exhaust air. There is. In other words, the enthalpy difference ΔE12 between the set temperature and humidity and the cold exhaust gas is smaller than the enthalpy difference ΔE13 between the set temperature and humidity and the outside air. In this case, the conditioned air selection means 91d (i.e., CPU) in the control device 91 selects as the conditioned air the heat medium that requires less energy to approach the set temperature and humidity, that is, the cold exhaust gas discharged by the drying oven heat pump 81. do. At this time, the CPU of the control device 91 performs control to open the cold exhaust intake damper and close the outside air intake damper, and takes the cold exhaust into the booth air conditioner 41 and uses it as conditioned air. Incidentally, this kind of situation is likely to occur in the summer when the outside air inside the facility is hot and humid.

Further, although not shown in the figure, neither the enthalpy E3 of the outside air nor the enthalpy E2 of the cold exhaust air falls within the predetermined range, and the enthalpy E2 of the cold exhaust air has a larger value than the enthalpy E3 of the outside air. Think about the state. In this case, the enthalpy difference ΔE13 between the set temperature and humidity and the outside air is smaller than the enthalpy difference ΔE12 between the set temperature and humidity and the cold exhaust gas. In this case, the conditioned air selection means 91d selects the heat medium that requires less energy to bring the temperature and humidity close to the set temperature and humidity, that is, the outside air, as the conditioned air. At this time, the CPU of the control device 91 performs control to close the cold/heat exhaust intake damper and open the outside air intake damper, and takes the outside air into the booth air conditioner 41 and uses it as conditioned air.

Further, in the state shown in FIG. 5, the enthalpy E3 of the outside air and the enthalpy E2 of the cold exhaust gas both belong to the predetermined range, and the difference from the enthalpy E1 of the set temperature and humidity is relatively small. In this case, the conditioned air selection means 91d selects both the outside air and the cold exhaust air as the conditioned air. At this time, the CPU of the control device 91 performs control to open both the damper for cold exhaust air intake and the damper for outside air intake, and the mixed gas of outside air and cold exhaust air is taken into the booth air conditioner 41 to become conditioned air. . Note that the opening degrees of the cold exhaust exhaust intake damper and the outside air intake damper are not particularly limited and may be set arbitrarily, but here, the opening degrees are set to be equal.

After selecting the heat medium to be used as the conditioned air, the CPU of the control device 91 uses, for example, a conventionally known method in order to make the temperature and humidity reach the set temperature and humidity (i.e., the control target point P1 on the psychrometric diagram 101). Each control target is controlled by PID control. As a result of the above control, conditioned air suitable for supplying to the painting booth 11 is generated.

Therefore, according to this embodiment, the following effects can be obtained.

(1) In the air conditioning system 31 for painting equipment of this embodiment, among the heat and cold heat separated by the heat separation means (heat pump 81 for drying oven) of the exhaust gas reheating means, the heat is transmitted through heating of the exhaust gas from the drying oven 21. It is used for reheating the drying oven 21. On the other hand, the cold heat generated by the heat separation means after heat absorption is discharged without being utilized by the drying oven 21. The temperature and humidity of this cold exhaust gas is compared with the temperature and humidity of outside air, and if predetermined conditions are met, at least a portion of the cold exhaust gas is supplied to the booth air conditioner 41 as conditioned air. That is, the cold exhaust gas that was not used and was discarded in the drying oven 21 is effectively used as conditioned air for the coating booth 11 through the booth air conditioner 41. Therefore, it is possible to reduce the energy consumption required for air conditioning.

(2) In the air conditioning system 31 for painting equipment of this embodiment, the calculating means 91a calculates the enthalpy E1 of the set temperature and humidity, the enthalpy E3 of outside air, and the enthalpy E2 of cold exhaust gas. Based on the calculation results, the first comparing means 91b calculates and compares the enthalpy difference ΔE13 between the set temperature and humidity and the outside air and the enthalpy difference ΔE12 between the set temperature and humidity and the cold exhaust gas. Based on this comparison result, the conditioned air selection means 91d selects as conditioned air the one that has a smaller enthalpy difference with the set temperature and humidity, that is, the one that requires less energy to approach the set temperature and humidity, from outside air and cold/heated exhaust air. . As a result, it becomes possible to reduce energy consumption required for air conditioning.

(3) In the air conditioning system 31 for painting equipment of this embodiment, the second comparing means 91c determines whether both the enthalpy E3 of outside air and the enthalpy E2 of cold exhaust air belong to a predetermined range. If the difference between the enthalpy E2 of the outside air, the enthalpy E3 of the cold exhaust air, and the enthalpy E1 of the set temperature and humidity is relatively small, both the outside air and the cold exhaust air are selected as the conditioned air. In this case, frequent switching of the damper in response to small fluctuations in outside air and cold/heated exhaust gas is suppressed, so that stable temperature and humidity settings can be adjusted.

(4) In the painting equipment air conditioning system 31 of this embodiment, as shown in FIG. It is located near and adjacent to the air supply end. Therefore, the cold exhaust gas discharged from the drying oven heat pump 81 can be efficiently supplied to the booth air conditioner 41 over a short distance. This has an advantageous effect on reducing energy consumption required for air conditioning.

Note that each embodiment of the present invention may be modified as follows.

- In the above embodiment, the painting equipment air conditioning system 31 is configured using an indirect temperature control type heat pump as the air conditioner heat pump 51, but the present invention is not limited to this. For example, in an air conditioning system 31A for painting equipment according to another embodiment shown in FIG. 6, the system is configured using a direct expansion type heat pump H1. This direct expansion type heat pump H1 includes a heat radiation part 112, a heat absorption part 113, a compressor 114, and an expansion valve 115 on an annular refrigerant flow path 111 through which a refrigerant as a heat medium flows. The heat radiating section 112, which functions as a heat exchanger, and the drying oven 21 are connected in a flow path manner through an exhaust path 117. The secondary side of the heat exchanger 116 and the drying oven 21 are connected via a return path 118 in terms of a flow path. A blower fan 119 is provided on the return path 118. Further, the cold heat generated in the heat absorption section 113 which functions as a heat exchanger is discharged as cold exhaust gas, and is also supplied to the air supply side of the booth air conditioner 41. Note that in the system using the direct expansion type heat pump H1, the heat radiation section 112 and the heat absorption section 113 play the role of a heat exchanger, so there is no need to install a separate heat exchanger for heat transfer. Therefore, efficient heat transfer can be achieved.

- In the above embodiment, when both the outside air and the cold exhaust air are selected as conditioned air when the enthalpy E3 of the outside air and the enthalpy E2 of the cold exhaust air are both within a predetermined range, the mixing ratio of the two is made equal. However, it is not limited to this. For example, one may be greater than the other. Further, this mixing ratio may be made variable.

11...Painting booth 21...Drying oven 31...Air conditioning system for painting equipment 41...Booth air conditioner 81, H1...Heat pump 91 as heat separation means...Control device 91a as air conditioner control means...Calculation means 91b...First comparison Means 91c...Second comparison means 91d...Air conditioned air selection means E1...Enthalpy of set temperature and humidity E2...Enthalpy of cold and hot exhaust E3...Enthalpy of outside air ΔE12, ΔE13...Enthalpy difference E1max...Upper limit E1min...Lower limit

Claims (3)

An air conditioning system in a painting facility comprising a coating booth that applies paint to an object to be coated, and a drying oven that dries the paint on the object that has passed through the coating booth,
a booth air conditioner that supplies outside air, adjusts its temperature and humidity, and sends the air to the painting booth;
Exhaust gas reheating means includes a heat separation means for separating heat from the taken in outside air and discharging cold heat, and heats the exhaust gas from the drying furnace with the heat separated by the heat separation means and returns it to the drying furnace. and,
By supplying at least one of the cold exhaust gas and the outside air to the booth air conditioner as conditioned air based on a comparison result between the temperature and humidity of the cold exhaust gas generated by the thermal separation means and the temperature and humidity of the outside air. , an air conditioner control means for controlling the temperature and humidity supplied to the booth air conditioner to approach the set temperature and humidity ,
The air conditioner control means includes:
Calculation means for calculating the enthalpy of the set temperature and humidity, the enthalpy of the outside air, and the enthalpy of the cold heat exhaust based on the set temperature and humidity information, the temperature and humidity information of the outside air, and the temperature and humidity information of the cold heat exhaust;
Based on the enthalpy of the set temperature and humidity, the enthalpy of the outside air and the enthalpy of the cold exhaust air calculated by the calculating means, calculate the enthalpy difference between the set temperature and humidity and the outside air, and the difference between the set temperature and humidity and the cold exhaust air. a first comparison means for calculating and comparing the enthalpy difference of;
The enthalpy of the outside air and the enthalpy of the cold exhaust are compared with the upper and lower limits of a predetermined range set in advance with the enthalpy of the set temperature and humidity as the center value, and the enthalpy of the outside air and the enthalpy of the cold exhaust are determined. a second comparing means for determining whether both belong to the predetermined range;
conditioned air selection means for selecting at least one of the outside air and the cold exhaust air as the conditioned air;
The air conditioning air selection means includes:
If the condition that both the enthalpy of the outside air and the enthalpy of the cold exhaust air belong to the predetermined range is satisfied, both the outside air and the cold exhaust air are selected as the conditioned air,
If the conditions are not met and the enthalpy difference between the set temperature and humidity and the outside air is smaller, the outside air is selected as the conditioned air;
If the above conditions are not met and the enthalpy difference between the set temperature and humidity and the cold exhaust air is smaller, the cold exhaust air is selected as the conditioned air.
An air conditioning system for painting equipment that is characterized by: a cold heat transfer path connected to the air supply side of the booth air conditioner in order to transfer the cold exhaust gas generated by the thermal separation means;
a damper for cold exhaust gas intake, which is provided at the end of the cold heat transfer path and is capable of adjusting the amount of cold exhaust gas taken into the booth air conditioner by adjusting the opening degree;
an outside air intake damper that is installed on the air supply side of the booth air conditioner and that allows the amount of outside air intake to be adjusted by adjusting the opening degree;
The air conditioning system for painting equipment according to claim 1, further comprising: The air conditioner control means includes:
If the conditions are met, control is performed to open both the cold and hot exhaust intake damper and the outside air intake damper,
If the conditions are not met and the enthalpy difference between the set temperature and humidity and the outside air is smaller, control is performed to close the cold and hot exhaust intake damper and open the outside air intake damper,
If the conditions are not met and the enthalpy difference between the set temperature and humidity and the cold exhaust gas is smaller, control is performed to open the cold exhaust air intake damper and close the outside air intake damper.
The air conditioning system for painting equipment according to claim 2.

Images