Outdoor air handling air conditioner

Abstract

The objective is to provide an outdoor air treatment air conditioner that can properly conditioned the outside air even when the indoor temperature decreases. [Solution] An outdoor air processing air conditioner comprising a housing having an outdoor air introduction path and an indoor air exhaust path, a damper for adjusting the opening degree of a bypass path connecting the introduction path and the exhaust path, an introduction path side heat exchanger located in the introduction path, an exhaust path side heat exchanger located in the exhaust path, and a compressor for compressing a refrigerant, and a refrigerant circuit that transports heat by phase change of the refrigerant, wherein the opening degree of the damper and the airflow rate of the exhaust fan are changed so that the amount of airflow of outdoor air flowing from the introduction path to the exhaust path side heat exchanger increases as the amount of heat of the outdoor air to be processed in the introduction path side heat exchanger increases.

Description

Technical Field

[0001] The present invention relates to an outdoor air treatment air conditioner.

Background Art

[0002] In recent years, various air conditioning devices have been proposed (see, for example, Patent Documents 1-4).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0004] Some outdoor air treatment air conditioners are configured to have both an outdoor air introduction path and an indoor air exhaust path inside the housing, and use the heat of the indoor air passing through the exhaust path to condition the outdoor air in the introduction path. In such an outdoor air treatment air conditioner, examples of the heat transfer means between the introduction path and the exhaust path include those using a heat exchange element, those circulating water as a heat medium, and those using a refrigeration cycle involving a phase change.

[0005] Typically, indoor spaces contain heat sources such as electrical appliances and lighting. Furthermore, buildings with poor insulation and airtightness allow a large amount of heat from outside air and sunlight to enter the interior. Therefore, for example, in summer when it is desired to cool the outside air in the intake path, if a refrigeration cycle is used in which a heat exchanger in the exhaust path acts as a condenser and a heat exchanger in the intake path acts as an evaporator, these heat sources will be added to the condenser in the exhaust path. Consequently, the compressor in the refrigeration cycle will pressurize the refrigerant so that it condenses in the condenser where these heat sources are added.

[0006] However, due to recent energy-saving measures in electrical equipment and buildings, the amount of indoor heat flowing into the exhaust path is steadily decreasing. On the other hand, the number of days with high temperatures in the outside air is increasing due to the effects of global warming. Therefore, when using a refrigeration cycle to transport heat between the intake and exhaust paths, it is necessary to transport heat between outside air with a wide temperature range and indoor air with a low heat load, and the operating range required of the compressor is expanding. Furthermore, outdoor air handling air conditioners must be designed to have the capacity to handle the maximum heat load expected in summer. For this reason, for example, when the heat load of the indoor or outdoor air is small, even if the compressor is operated near the lower limit of its operating range, it is becoming increasingly difficult to adjust the temperature and humidity of the outside air flowing into the intake path to the appropriate control target values.

[0007] This invention has been made in view of the above problems, and aims to provide an outdoor air treatment air conditioner that can properly conditioned the outside air even when the indoor heat decreases. [Means for solving the problem]

[0008] To solve the above problems, the present invention provides a damper with adjustable opening in a bypass path that connects the introduction path and the exhaust path. As the amount of heat in the outside air to be processed by the heat exchanger in the introduction path increases, the damper's opening and the exhaust fan's airflow rate are changed so that the amount of outside air flowing from the introduction path through the bypass path to the heat exchanger on the exhaust path side increases.

[0009] More specifically, the present invention comprises a housing having an intake path for outside air and an exhaust path for indoor air; a supply fan positioned downstream in the intake path, which blows air from an outside air intake upstream of the intake path towards the indoor space downstream of the intake path; an exhaust fan positioned downstream in the exhaust path, which blows air from the indoor space upstream of the exhaust path towards the air outlet downstream of the exhaust path; and a damper that adjusts the opening degree of a bypass path connecting the portion of the intake path upstream of the supply fan and the portion of the exhaust path upstream of the exhaust fan. The air conditioner comprises an intake-side heat exchanger located in the intake path, an exhaust-side heat exchanger located in the exhaust path, and a compressor for compressing the refrigerant, and a refrigerant circuit that transports heat by phase change of the refrigerant, and a control device capable of controlling at least a supply fan, an exhaust fan, a damper, and the refrigerant circuit, wherein the control device changes the opening of the damper and the airflow rate of the exhaust fan so that the amount of outside air flowing from the intake path to the exhaust-side heat exchanger through the bypass path increases as the amount of outside air to be processed in the intake-side heat exchanger increases.

[0010] Here, the enclosure is not limited to having a single external form, but rather to any structure that integrally forms an intake path for outside air and an exhaust path for indoor air. For example, the enclosure may have the appearance of a rectangular parallelepiped, or it may have the appearance of a pair of cylindrical bodies joined together, each forming an intake path and an exhaust path, respectively.

[0011] Furthermore, a bypass route is a path that allows outside air that has entered the intake route to flow to the exhaust route without passing through the indoor space, and is not limited to being formed by a pipe. The bypass route can be any form that allows air to flow between the intake route and the exhaust route, and may be, for example, a pipe connecting the intake route and the exhaust route, a through-hole provided in the wall separating the intake route and the exhaust route, or any other form of route.

[0012] In the above-mentioned outdoor air handling air conditioner, as the amount of heat in the outdoor air to be processed by the intake path heat exchanger increases, the damper opening and the exhaust fan's airflow rate are changed so that the amount of outdoor air flowing from the intake path through the bypass path to the exhaust path heat exchanger increases. Therefore, even if the indoor temperature decreases, the capacity of the exhaust path heat exchanger is adjusted by the damper and exhaust fan, allowing for proper air conditioning of the outdoor air.

[0013] Furthermore, the inlet-side heat exchanger comprises a first inlet-side heat exchanger and a second inlet-side heat exchanger located downstream of the first inlet-side heat exchanger in the inlet path. In the case of cooling, the control device may form a circuit in the refrigerant circuit such that the refrigerant that has passed through the first inlet-side heat exchanger flows to the exhaust-side heat exchanger and the second inlet-side heat exchanger by a compressor, with the first inlet-side heat exchanger functioning as an evaporator, the exhaust-side heat exchanger as a condenser, and the second inlet-side heat exchanger as a reheater. This allows for excessive cooling of the outside air in the first inlet-side heat exchanger to dehumidify the outside air, while simultaneously reheating the air supplied to the indoor space in the second inlet-side heat exchanger.

[0014] Furthermore, the control device may increase the ratio of the refrigerant flow rate in the exhaust path heat exchanger to the second inlet path heat exchanger as the temperature of the outside air flowing into the inlet path increases. This increases the flow rate of refrigerant passing through the exhaust path heat exchanger in response to the rise in outside air temperature, thereby increasing the capacity of the condenser in the refrigeration cycle during cooling.

[0015] Furthermore, the above-mentioned outside air handling air conditioner may be located upstream of the exhaust path heat exchanger in the exhaust path, and may further include a evaporator for evaporating the condensate generated in the first inlet path heat exchanger. This allows the cooling energy of the condensate in the first inlet path heat exchanger to be used for condensing the refrigerant in the exhaust path heat exchanger, thus improving the efficiency of the refrigeration cycle during cooling. This makes it possible to increase the rate.

[0016] Further, the housing is internally formed such that the introduction path and the exhaust path are adjacent to each other with the inner wall of the housing therebetween, and the air flows in the introduction path and the air flows in the exhaust path are in opposite directions to each other. The bypass path may be formed by a through-hole that penetrates the inner wall of the housing and whose penetration direction is obliquely downstream with respect to the air flow directions in the introduction path and the exhaust path. According to this, since the air flowing into the introduction path or the exhaust path does not directly flow into the bypass path, the air flow in the bypass path can be caused by the pressure difference between the introduction path and the exhaust path.

[0017] Further, the exhaust path side heat exchanger has a first exhaust path side heat exchanger and a second exhaust path side heat exchanger arranged in parallel in the air flow direction in the exhaust path. When the control device performs a defrosting operation during heating in which the exhaust path side heat exchanger serves as an evaporator, the refrigerant circuit may be formed such that the first exhaust path side heat exchanger and the second exhaust path side heat exchanger are alternately defrosted. According to this, it is possible to alternately perform a defrosting operation on the first exhaust path side heat exchanger and the second exhaust path side heat exchanger while continuing ventilation and air conditioning of the indoor space by the outdoor air treatment air conditioner.

Advantages of the Invention

[0018] With the above-described outdoor air treatment air conditioner, even if the heat in the room decreases, the outdoor air can be properly air-conditioned.

Brief Description of the Drawings

[0019] [Figure 1] FIG. 1 is a view showing an outdoor air treatment air conditioner. [Figure 2] FIG. 2 is a view showing the refrigerant circuit of the outdoor air treatment air conditioner. [Figure 3] FIG. 3 is a table schematically showing the control contents realized in the outdoor air treatment air conditioner. [Figure 4] FIG. 4 is a first view showing the effects of the outdoor air treatment air conditioner. [Figure 5] FIG. 5 is a second view showing the effects of the outdoor air treatment air conditioner. [Figure 6]FIG. 6 is a diagram showing a modified example of a refrigerant circuit of an outdoor air handling air conditioner.

Embodiments for Carrying Out the Invention

[0020] Hereinafter, embodiments of the present invention will be described. The embodiments shown below are examples of embodiments of the present invention, and do not limit the technical scope of the present invention to the following aspects.

[0021] <Device Configuration> FIG. 1 is a diagram showing an outdoor air handling air conditioner 1. The outdoor air handling air conditioner 1 is an integrated ceiling-mounted air conditioner installed in the ceiling space. The outdoor air handling air conditioner 1 has an overall rectangular parallelepiped outer shape, and the inside of the housing 2 is partitioned so that the exhaust path 3 and the introduction path 4 are adjacent to each other with the housing inner wall interposed therebetween. In the present embodiment, the outdoor air handling air conditioner 1 will be described as a ceiling-mounted air conditioner, but the outdoor air handling air conditioner 1 may be an air conditioner installed on the floor, an air conditioner installed on the wall surface, or an air conditioner of other forms. Further, the housing 2 is not limited to having a rectangular parallelepiped outer shape, and for example, it may have an appearance such as two cylindrical bodies joined together, or an appearance of various other shapes. Each component in the housing 2 is controlled by a control device that issues various control signals based on a temperature sensor, a humidity sensor built in the housing 2, a command from a higher-level device, and the like. This control device may be built in the housing 2 of the outdoor air handling air conditioner 1, or may be provided separately from the housing 2 on the outdoor air handling air conditioner 1.

[0022] On the exterior surface of the outdoor air handling air conditioner 1, there are an air inlet for allowing return air (RA: Return Air) to flow from the indoor space into the exhaust path 3, and an exhaust (EA: Exhaust Air) from the exhaust path 3 to the outside outlet for allowing it to flow out, and outside air (OA: Outside Air) flowing from the outside into the introduction path 4 An air inlet (an example of an "outside air intake" as referred to in this application) and an air outlet are provided for discharging the supply air (SA) from the introduction path 4 into the indoor space. Both the air inlet and air outlet form circular openings, allowing for the connection of ducts with a circular cross-section. The air inlet and air outlet may be formed by openings other than circular.

[0023] The outdoor air handling air conditioner 1 has an exhaust path 3 and an introduction path 4, enabling it to introduce outside air into the indoor space to be air-conditioned and exhaust the indoor air to the outside. Furthermore, the outdoor air handling air conditioner 1 uses the thermal energy of the air passing through the exhaust path 3 to adjust the temperature and humidity of the outside air passing through the introduction path 4. The outdoor air handling air conditioner 1 uses heat exchangers installed in the exhaust path 3 and the introduction path 4 to adjust the temperature and humidity of the outside air using the thermal energy of the indoor air through a refrigeration cycle involving a phase change. For this reason, the following components are arranged in the exhaust path 3 and the introduction path 4.

[0024] Specifically, the exhaust path 3 is equipped with an exhaust fan 5 for exhausting indoor air to the outside. The intake path 4 is equipped with an intake fan 6 for supplying outside air to the indoor space. As a result, the outdoor air processing air conditioner 1 can operate the exhaust fan 5 to exhaust indoor air to the outside and operate the intake fan 6 to supply outside air to the indoor space. The exhaust fan 5 and the intake fan 6 are positioned so that their airflow directions are opposite within the housing 2. Therefore, the airflow through the exhaust path 3 and the airflow through the intake path 4 are in opposite directions.

[0025] Furthermore, a heat exchanger 7 (an example of the "exhaust path side heat exchanger" as referred to in this application) is provided in the exhaust path 3. In addition, a heat exchanger 8 (an example of the "inlet path side heat exchanger" and "first inlet path side heat exchanger" as referred to in this application) and a heat exchanger 9 (an example of the "inlet path side heat exchanger" and "second inlet path side heat exchanger" as referred to in this application) are provided in the introduction path 4. Heat exchangers 7, 8, and 9 are components that constitute the refrigerant circuit that realizes the refrigeration cycle, and the refrigerant gas circulated by the compressor 14 expands or condenses. For example, when cooling is performed by the outside air processing air conditioner 1 because the outside air is hot, such as in summer, heat exchanger 7 functions as a condenser and heat exchanger 8 functions as an evaporator. This makes it possible to use the thermal energy of the air in the exhaust path 3 to cool the outside air supplied to the indoor space. Furthermore, for example, if heating is performed using the outside air handling air conditioner 1 because the outside air is cold, such as in winter, the heat exchanger 7 functions as an evaporator and the heat exchanger 8 functions as a condenser. This makes it possible to heat the outside air supplied to the indoor space using the thermal energy of the air in the exhaust path 3.

[0026] Furthermore, a vaporizer 7J is provided upstream of the heat exchanger 7 in the exhaust path 3. The vaporizer 7J is a device that utilizes the cooling energy of condensed water generated in the heat exchanger 8 during summer cooling by vaporizing the condensed water, thereby aiding in the condensation of the heat exchanger 7. The supply of condensed water to the vaporizer 7J may be carried out, for example, by a pump that starts and stops according to the water level in a drain pan located at the bottom of the heat exchanger 8, or a water supply tray that communicates with the drain pan located at the bottom of the heat exchanger 8 may be provided at the bottom of the vaporizer 7J, and the vaporizer 7J may be constructed of a water-absorbing material that draws up the water from the water supply tray. If such a vaporizer 7J is provided, the cooling energy of the condensed water in the heat exchanger 8 can be utilized for the condensation of the refrigerant in the heat exchanger 7, thereby increasing the efficiency of the refrigeration cycle during cooling.

[0027] Furthermore, the outdoor air handling air conditioner 1 makes it possible to arrange the heat exchanger 7 in the exhaust path 3 and the heat exchangers 8 and 9 in the introduction path 4 so that they are not adjacent to each other within the housing 2 by making the airflow in the exhaust path 3 and the airflow in the introduction path 4 in opposite directions. In other words, as shown in Figure 1, the outdoor air handling air conditioner 1 arranges the heat exchanger 7 in the exhaust path 3 and the heat exchangers 8 and 9 in the introduction path 4 so that they are not adjacent to each other. As can be seen in Figure 1, the heat exchangers 7, 8, and 9 are relatively horizontally arranged. These components require width. Therefore, if heat exchanger 7 and heat exchangers 8 and 9 are arranged adjacent to each other, the housing 2 will inevitably become larger. In this respect, in the outdoor air processing air conditioner 1 of this embodiment, heat exchanger 7 and heat exchangers 8 and 9 are arranged so that they are not adjacent to each other, making it possible to shorten the dimensions of the housing 2 (the length of heat exchangers 7, 8, and 9 in the longitudinal direction).

[0028] In this embodiment, as shown in Figure 1, the compressor 14 that compresses the refrigerant gas is located within the exhaust path 3. This is to take into consideration the effect of the heat generated by the compressor 14 itself on the air supplied to the indoor space. However, the compressor 14 may be located not in the exhaust path 3, but for example, within the introduction path 4 or outside the housing 2.

[0029] Furthermore, a filter 11 is provided upstream of the heat exchanger 8 in the intake path 4. The filter 11 collects dust and other particles contained in the outside air. As a result, clean air is supplied to the indoor space into which the air that has passed through the intake path 4 is supplied.

[0030] Furthermore, a humidifier 10 is provided downstream of the heat exchanger 9 in the intake path 4. The humidifier 10 humidifies the air passing through the intake path 4. The humidifier 10 humidifies the air using water supplied from a water supply path connected to the outdoor air processing unit 1.

[0031] The components are arranged in the exhaust path 3 and the intake path 4 as described above. Therefore, the return air flowing into the exhaust path 3 passes through the heat exchanger 7 and the exhaust fan 5 in order before being exhausted outdoors. The return air flowing into the exhaust path 3 cools or heats the heat exchanger 7 as it passes through it. In addition, the outside air flowing into the intake path 4 passes through the filter 11, the heat exchanger 8, the heat exchanger 9, the humidifier 10, and the supply fan 6 in order before being supplied to the indoor space. The outside air flowing into the intake path 4 is cooled or heated as it passes through the heat exchanger 8 and the heat exchanger 9, and is humidified by the humidifier 10.

[0032] Furthermore, the outdoor air handling unit 1 is provided with a damper 12 and a bypass hole 13 for connecting the exhaust path 3 and the introduction path 4. The bypass hole 13 is a through-hole that penetrates the inner wall of the housing that divides the inside of the outdoor air handling unit 1 into the exhaust path 3 and the introduction path 4, and forms a bypass path that connects the part of the exhaust path 3 upstream of the heat exchanger 7 and the part of the introduction path 4 upstream of the heat exchanger 8. The damper 12 is an electrically operated damper that can adjust the opening degree of the bypass hole 13.

[0033] The bypass hole 13 is positioned diagonally downstream with respect to the airflow direction of the exhaust path 3 and the intake path 4. Therefore, the bypass hole 13 faces the air outlets of the exhaust path 3 and the intake path 4, but not the air inlets of the exhaust path 3 and the intake path 4. Consequently, air flowing in from the air inlet of the exhaust path 3 does not directly flow into the bypass hole 13. Similarly, air flowing in from the air inlet of the intake path 4 does not directly flow into the bypass hole 13. Therefore, air flow in the bypass hole 13 is driven by the pressure difference between the exhaust path 3 and the intake path 4. Thus, the amount of air flowing in the bypass hole 13 is primarily influenced by the airflow rates of the exhaust fan 5 and the supply fan 6, as well as the opening degree of the damper 12.

[0034] Figure 2 shows the refrigerant circuit C of the outdoor air handling air conditioner 1. The outdoor air handling air conditioner 1 has a refrigerant circuit C as shown in Figure 2. In addition to the heat exchangers 7, 8, 9 and compressor 14 mentioned above, the refrigerant circuit C has a switching valve 15, a third expansion valve 16, a second expansion valve 17, a first expansion valve 18, and a solenoid valve 19. The switching valve 15 is a solenoid valve for switching the circuit configuration of the refrigerant circuit C between cooling and heating. The third expansion valve 16, the second expansion valve 17, and the first expansion valve 18 are valves for expanding the refrigerant gas while reducing the pressure. The solenoid valve 19 is a valve that opens and closes the refrigerant circuit. These valves are external It is electrically controlled by the control device of the air treatment air conditioner 1.

[0035] For example, when cooling is performed with the outdoor air handling air conditioner 1, two paths are formed: one where the refrigerant gas compressed by the compressor 14 passes through the heat exchanger 7 via the switching valve 15, is depressurized by the third expansion valve 16 and the first expansion valve 18, passes through the heat exchanger 8, and returns to the compressor 14 via the switching valve 15; and another where the refrigerant gas compressed by the compressor 14 passes through the heat exchanger 9 via the solenoid valve 19, is depressurized by the second expansion valve 17 and the first expansion valve 18, passes through the heat exchanger 8, and returns to the compressor 14 via the switching valve 15. This forms a circuit in which the heat exchanger 7 functions as a condenser, the heat exchanger 8 as an evaporator, and the heat exchanger 9 as a reheater. In other words, the high-temperature, high-pressure refrigerant gas compressed by the compressor 14 is cooled and condensed in the heat exchanger 7. Also, the refrigerant gas sent from the compressor 14 to the heat exchanger 9 is cooled and condensed by heating the air in the heat exchanger 9. Then, the refrigerant gas that is cooled and condensed as it passes through the heat exchanger 7 vaporizes and becomes cold when the pressure is reduced by the third expansion valve 16 and the first expansion valve 18, and cools the air as it passes through the heat exchanger 8. Also, the refrigerant gas that is cooled and condensed as it passes through the heat exchanger 9 by heating the air vaporizes and becomes cold when the pressure is reduced by the second expansion valve 17 and the first expansion valve 18, and cools the air as it passes through the heat exchanger 8. In this way, a cooling circuit configuration is realized in the refrigerant circuit C that utilizes the thermal energy of the air passing through the exhaust path 3 to cool the air passing through the introduction path 4.

[0036] Furthermore, for example, when heating is performed with the outdoor air handling air conditioner 1, a path is formed in which the refrigerant gas compressed by the compressor 14 passes through the switching valve 15, goes through the heat exchanger 8, is depressurized by the first expansion valve 18 and the third expansion valve 16, passes through the heat exchanger 7, and returns to the compressor 14 again via the switching valve 15. This forms a circuit in which the heat exchanger 8 functions as a condenser and the heat exchanger 7 functions as an evaporator. In other words, the high-temperature, high-pressure refrigerant gas compressed by the compressor 14 is cooled and condensed by heating the air in the heat exchanger 8. The refrigerant gas that has been cooled and condensed by heating the air as it passes through the heat exchanger 8 is vaporized and becomes cold as it is depressurized by the first expansion valve 18 and the third expansion valve 16, and is heated by the air as it passes through the heat exchanger 7. Thus, a heating circuit configuration is realized in the refrigerant circuit C for heating the air passing through the introduction path 4 using the thermal energy of the air passing through the exhaust path 3.

[0037] The outdoor air handling air conditioner 1, by configuring the refrigerant circuit C as described above, cools, heats, and dehumidifies the air supplied to the indoor space from the introduction path 4 so that the indoor space reaches the set temperature and humidity. In addition, the outdoor air handling air conditioner 1 humidifies the air supplied to the indoor space from the introduction path 4 so that the indoor space reaches the set humidity by appropriately adjusting the water supply to the humidifier 10 with the water supply valve 20.

[0038] As described above, the outdoor air handling air conditioner 1 is an air conditioner that integrates the heat source unit using the refrigerant circuit C with the exhaust path 3 and the intake path 4, thus eliminating the need for piping connection work and fan installation work. Furthermore, since the outdoor air handling air conditioner 1 is an integrated device that incorporates all the components of the refrigerant circuit C, the amount of refrigerant gas used, such as alternative fluorocarbons, can be reduced as much as possible by shortening the piping connecting the components compared to a separate device where the components of the refrigerant circuit are located inside and outside the device. In addition, since the heat exchanger 7 of the refrigerant circuit C is located in the exhaust path 3, it is possible to utilize the waste heat of the air exhausted to the outside, which is cooler than the outside air in summer and warmer than the outside air in winter, resulting in high efficiency for the refrigerant circuit C.

[0039] <Control details> Figure 3 is a schematic table showing the control details implemented in the outdoor air handling unit 1. The outdoor air handling unit 1 has the capacity to handle the maximum heat load expected in summer, but even when the indoor heat load is small, it performs the following control to adjust the temperature and humidity of the outside air flowing into the introduction path 4 to appropriate control target values.

[0040] In this section, we will explain the control settings during cooling in the summer. Therefore, "high temperature," "medium temperature," and "low temperature" in the following outdoor air conditions all refer to temperatures higher than the control target value for the indoor space temperature. Also, "high humidity" in the following outdoor air conditions refers to humidity higher than the control target value for the indoor space humidity. If the outside temperature is lower than the control target value for the indoor space temperature, the compressor 14 is not operated, and outside air is supplied directly to the indoor space for outside air cooling, or the refrigerant circuit C is configured for heating and heating operation is performed.

[0041] <<When the outside air conditions are high temperature and high humidity>> When the outside air is hot and humid, the moisture in the outside air flowing into the intake path 4 can be sufficiently removed by condensation when the air is cooled to a predetermined temperature target value in the heat exchanger 8. Therefore, even without reheating by the heat exchanger 9, the temperature and humidity of the air supplied from the intake path 4 to the indoor space can be brought to the predetermined control target values ​​by cooling in the heat exchanger 8 alone. For this reason, when the outside air is hot and humid, each component of the outside air processing air conditioner 1 is controlled as follows.

[0042] In other words, when the outside air is hot and humid, the solenoid valve 19 and the second expansion valve 17 are fully closed, the third expansion valve 16 is fully open, and the opening of the first expansion valve 18 is adjusted according to the degree of superheating of the refrigerant gas, so that the entire amount of refrigerant gas flows to the heat exchanger 8 instead of the heat exchanger 9 in the outside air processing air conditioner 1. As a result, the outside air processing air conditioner 1 performs cooling and dehumidification operation in which 100% of the refrigerant gas flows to the heat exchanger 8 without reheating in the heat exchanger 9.

[0043] When the outside air is hot and humid, the amount of sensible and latent heat in the outside air processed by the heat exchanger 8 is large. Therefore, the outside air processing air conditioner 1 operates the exhaust fan 5 at high speed and maximizes the opening of the damper 12 in order to increase the cooling capacity of the heat exchanger 7. As a result, the amount of outside air that flows into the introduction path 4, excluding the amount supplied to the indoor space by the supply fan 6, flows into the exhaust path 3 through the bypass hole 13, passes through the heat exchanger 7, and is exhausted outside by the exhaust fan 5. In other words, the outside air processing air conditioner 1 controls the exhaust fan 5 and damper 12 so that the heat exchanger 7 performs the same function as the condenser of an outdoor unit installed outdoors. This makes it possible for the outside air processing air conditioner 1 to supply hot and humid outside air to the indoor space at a predetermined control target value.

[0044] <<When the outside temperature is moderate and the humidity is high>> When the outside air is at a moderate temperature (lower than high temperature) and high humidity, the amount of cooling required by the heat exchanger 8 is less than when it is at high temperature and high humidity. Therefore, when the outside air conditions are moderate temperature and high humidity, the moisture in the outside air flowing into the introduction path 4 cannot be sufficiently removed by condensation alone when the air is cooled to a predetermined temperature target value in the heat exchanger 8. Accordingly, when the outside air conditions are moderate temperature and high humidity, the temperature of the supply air supplied to the indoor space is adjusted by the amount of heating in the heat exchanger 9, and excessive air cooling is performed in the heat exchanger 8 to remove humidity.

[0045] In other words, when the outside air is at a moderate temperature and high humidity, the solenoid valve 19 in the outside air handling air conditioner 1 opens to allow the refrigerant gas to flow to the heat exchanger 9, the opening degree of the third expansion valve 16 is adjusted according to the load factor of the heat exchanger 9, the opening degree of the second expansion valve 17 is adjusted according to the temperature of the supply air supplied to the indoor space, and the opening degree of the first expansion valve 18 is adjusted according to the degree of superheating of the refrigerant gas. As a result, the outside air handling air conditioner 1 performs reheat dehumidification operation, which involves cooling and dehumidifying the heat exchanger 8 while reheating the heat exchanger 9.

[0046] When the outside air is at a moderate temperature and high humidity, the amount of sensible and latent heat of the outside air processed by heat exchangers 8 and 9 is less than when the outside air conditions are high temperature and high humidity. Therefore, the outside air processing air conditioner 1 is configured such that the cooling capacity of heat exchanger 7 is slightly lower than when the outside air conditions are high temperature and high humidity. To achieve this, the exhaust fan 5 is operated at a medium speed, and the damper 12 is opened to an intermediate position (between fully closed and fully open). As a result, of the outside air flowing into the introduction path 4, the amount of air remaining after deducting the amount supplied to the indoor space by the supply fan 6 flows into the exhaust path 3 through the bypass hole 13 at a lower flow rate than when the outside air conditions are high temperature and high humidity, and is exhausted outside through the heat exchanger 7 and the exhaust fan 5. The outside air processing air conditioner 1 operates with a reduced condensation capacity in the heat exchanger 7 compared to when the outside air conditions are high temperature and high humidity, and thus operates with a suppressed capacity of the refrigerant circuit C. For this reason, even if the indoor heat load is small and the return air from the indoor space is at a low temperature, the condensation capacity in the heat exchanger 7 is suppressed by the damper 12 and the exhaust fan 5, and even if the compressor 14 is operated near the lower limit of its operating range, it is possible to supply the indoor space with outside air flowing into the introduction path 4 at a predetermined control target temperature and humidity.

[0047] <<When the outside air conditions are low temperature and high humidity>> When the outside air is at a low temperature (lower than the moderate temperature) and high humidity, the amount of cooling required by the heat exchanger 8 is less than when the outside air is at a moderate temperature and high humidity. Therefore, when the outside air conditions are low temperature and high humidity, the circuit configuration of the refrigerant circuit C is basically the same as when the outside air conditions are at a moderate temperature and high humidity, but the flow rate of the refrigerant in the heat exchanger 9 increases and the flow rate of the refrigerant in the heat exchanger 8 decreases. Furthermore, when the outside air is at a low temperature and high humidity, the amount of sensible and latent heat of the outside air processed by the heat exchangers 8 and 9 is even less than when the outside air conditions are at a moderate temperature and high humidity. Therefore, the exhaust fan 5 is operated at a low speed and the opening of the damper 12 is set to the minimum (fully closed or slightly open). As a result, of the outside air that flows into the introduction path 4, the amount of air remaining after deducting the amount supplied to the indoor space by the supply fan 6 flows into the exhaust path 3 through the bypass hole 13 at an even lower flow rate than when the outside air conditions are at a moderate temperature and high humidity, passes through the heat exchanger 7, and is exhausted outside from the exhaust fan 5. The outdoor air handling air conditioner 1 operates with a further reduced condensation capacity in the heat exchanger 7 compared to when the outdoor air conditions are moderate temperature and high humidity. As a result, the refrigerant circuit C operates with a further suppressed capacity. Therefore, for example, even when the indoor heat load is small and the return air from the indoor space is at a low temperature, the condensation capacity in the heat exchanger 7 is further suppressed by the damper 12 and exhaust fan 5. This makes it possible to supply the indoor space with outside air flowing into the introduction path 4 at a predetermined control target temperature and humidity, even when the compressor 14 is operated near the lower limit of its operating range.

[0048] <Effects> The effectiveness of the outdoor air processing air conditioner 1 was verified using an actual unit, and the results are shown below. Figure 4 is the first diagram showing the effectiveness of the outdoor air processing air conditioner 1. In Figure 4, the dehumidification performance of the outdoor air processing air conditioner 1 according to this embodiment is used as an example, and the dehumidification performance of a conventional outdoor air processing device is used as a comparative example, with the difference in performance between the two shown in a psychrometric chart. The target line shown in Figure 4 indicates the target value of absolute humidity in the indoor space during summer, and it is desirable that the absolute humidity be below this target line.

[0049] As described above, the outdoor air treatment air conditioner 1 according to this embodiment is an air conditioner that adjusts the condensation capacity in the heat exchanger 7 using a damper 12 and an exhaust fan 5. On the other hand, the conventional outdoor air treatment device according to the comparative example has the same basic configuration as the outdoor air treatment air conditioner 1, but does not have a bypass path such as a bypass hole 13 between the intake path and the exhaust path, and does not adjust the condensation capacity using a damper 12 and an exhaust fan 5 as the outdoor air treatment air conditioner 1 according to the embodiment. In other words, in the conventional outdoor air treatment device according to the comparative example, the exhaust fan operates at an airflow rate that matches the required ventilation rate. Also, in the conventional outdoor air treatment device according to the comparative example, the temperature of the air passing through the exhaust path matches the temperature of the indoor space. For this reason, the conventional outdoor air treatment device according to the comparative example cannot freely adjust the capacity of the heat exchanger installed in the exhaust path.

[0050] Therefore, for example, when the indoor heat load is small, the comparative example may have difficulty adjusting the outside air temperature and humidity to appropriate control target values. On the other hand, in the example, in the heat exchanger 7 Because the condensation capacity is adjusted by the damper 12 and the exhaust fan 5, it is possible to adjust the temperature and humidity of the outside air to appropriate control target values ​​even when the heat load inside the room is small. Therefore, as shown in Figure 4, the embodiment makes it easier to adjust the temperature and humidity of the outside air supplied to the indoor space to predetermined control target values ​​compared to the comparative example.

[0051] Figure 5 is the second figure showing the effect of the outdoor air treatment air conditioner 1. In Figure 5, the difference in performance between the example and the comparative example is shown in the time-series data of indoor temperature and indoor humidity graphs. In the graph of Figure 5, the changes in indoor temperature and indoor humidity in the comparative example are shown by dashed lines, and the changes in indoor temperature and indoor humidity in the example are shown by solid lines.

[0052] As can be seen from the graph in Figure 5, the comparative example shows a large range of fluctuations in indoor temperature and humidity. On the other hand, the embodiment shows a small range of fluctuations in indoor temperature and humidity. This is because, when the indoor heat load is small, in the comparative example the compressor starts and stops frequently even when the refrigeration cycle is operated at minimum capacity, whereas in the embodiment the refrigeration cycle can be operated at a lower capacity, thus suppressing the repeated starting and stopping of the compressor.

[0053] As mentioned above, due to recent energy-saving measures in electrical equipment and buildings, the amount of indoor heat flowing into the exhaust path 3 is steadily decreasing. On the other hand, the number of days with high temperatures in the outside air is increasing due to the effects of global warming. Therefore, when using a refrigeration cycle to transport heat between the exhaust path 3 and the intake path 4, it is necessary to transport heat between outside air with a wide temperature range and indoor air with a low heat load, which requires expanding the operating range required of the compressor 14. Furthermore, the outdoor air processing air conditioner 1 needs to be designed to have the capacity to handle the maximum heat load expected in summer. For this reason, in a device configuration in which the condensation capacity of the heat exchanger 7 is not adjusted by the damper 12 and the exhaust fan 5, for example, when the indoor heat load is small, even if the compressor 14 is operated near the lower limit of its operating range, it is difficult to adjust the temperature and humidity of the outside air flowing into the intake path 4 to appropriate control target values ​​and supply it to the indoor space. However, in the outdoor air handling air conditioner 1 of the above embodiment, the damper 12 and the exhaust fan 5 adjust the condensation capacity of the heat exchanger 7, so that even when the indoor heat load is small or the temperature and humidity of the outside air are low, supercooling of the heat exchanger 7 can be suppressed, and the temperature and humidity of the outside air flowing into the introduction path 4 can be adjusted to appropriate control target values.

[0054] <Variation> Furthermore, the outdoor air handling air conditioner 1 may be modified as follows. Figure 6 shows a modified example of the refrigerant circuit C of the outdoor air handling air conditioner 1. The refrigerant circuit C of the outdoor air handling air conditioner 1 may have a heat exchanger 7A (an example of the "first exhaust path side heat exchanger" as referred to in this application) and a heat exchanger 7B (an example of the "second exhaust path side heat exchanger" as referred to in this application) in parallel, corresponding to the heat exchanger 7. In this case, two third expansion valves 16A and 16B corresponding to each heat exchanger 7A and 7B are provided as expansion valves corresponding to the third expansion valve 16. In addition, solenoid valves 21A and 21B are provided to open and close the circuit connecting the discharge side of the compressor 14 and the inlet side of each heat exchanger 7A and 7B.

[0055] In the modified refrigerant circuit C described above, during winter heating when frost may form on the heat exchanger 7, it is possible to alternately defrost the heat exchanger 7A and the heat exchanger 7B while continuing ventilation and air conditioning of the indoor space by the outdoor air handling air conditioner 1. In the modified refrigerant circuit C, for example, when defrosting the heat exchanger 7A, the third expansion valve 16A is closed and the solenoid valve 21A is opened. As a result, the high-temperature, high-pressure refrigerant gas pressurized by the compressor 14 passes through the heat exchanger 7A, making it possible to remove the frost attached to the heat exchanger 7A by heating. When switching the target of the defrosting operation from the heat exchanger 7A to the heat exchanger 7B, the solenoid valve 21A is closed and the third expansion valve 16A is set to the control state (refrigerant flow rate adjustment state), and then the third expansion valve 16B is closed and the solenoid valve 21B is opened.

[0056] Furthermore, the outdoor air treatment air conditioner 1 can be modified as appropriate without altering the essence of the present invention.

[0057] For example, the damper 12 and bypass hole 13 pairs may be provided in two stages, upper and lower, and the damper 12 may be controlled in stages, with the damper 12 of one stage opening completely before the damper 12 of the other stage begins to open. Alternatively, the damper 12 may only be able to operate in either fully closed or fully open positions, and the flow rate of the entire bypass path may be changed in stages by providing multiple stages of damper 12 and bypass hole 13 pairs.

[0058] Furthermore, the refrigerant circuit C may have some of its piping and the compressor 14 located on the outside of the housing 2. [Explanation of symbols]

[0059] C··Refrigerant circuit 1. Outdoor air handling air conditioner 2. Cabinet 3. Exhaust path 4. Implementation Route 5. Exhaust fan 6. Intake fan 7,7A,7B·Heat exchanger 7J ·· Evaporator 8...Heat exchanger 9...Heat exchanger 10...humidifier 11. Filter 12. Damper 13. Bypass hole 14. Compressor 15. Switching valve 16, 16A, 16B... Third expansion valve 17. Second expansion valve 18. First expansion valve 19, 21A, 21B... Solenoid valves 20. Water supply valve

Claims

1. A housing having an intake path for outside air and an exhaust path for indoor air inside, A supply air fan is located downstream in the aforementioned intake path and blows air from an outside air intake upstream of the intake path toward the indoor space downstream of the intake path. An exhaust fan is positioned downstream in the aforementioned exhaust path and blows air from the indoor space upstream of the exhaust path toward the air outlet downstream of the exhaust path. A damper that adjusts the opening degree of a bypass path that connects the portion of the intake path upstream of the intake fan and the portion of the exhaust path upstream of the exhaust fan, A refrigerant circuit having an introduction path side heat exchanger located in the introduction path, an exhaust path side heat exchanger located in the exhaust path, and a compressor for compressing the refrigerant, and performing heat transport by a phase change of the refrigerant, It comprises at least the supply fan, the exhaust fan, the damper, and a control device capable of controlling the refrigerant circuit, The control device changes the damper opening and the exhaust fan airflow rate so that the amount of outside air flowing from the introduction path to the exhaust path heat exchanger increases as the amount of outside air to be processed in the introduction path heat exchanger increases. Outdoor air handling air conditioner.

2. The aforementioned introduction path side heat exchanger comprises a first introduction path side heat exchanger and a second introduction path side heat exchanger located downstream of the first introduction path side heat exchanger in the introduction path. In the case of cooling, the control device causes the refrigerant circuit to form such that the first heat exchanger on the introduction path side functions as an evaporator, the heat exchanger on the exhaust path side functions as a condenser, and the second heat exchanger on the introduction path side functions as a reheater, by which the refrigerant that has passed through the first heat exchanger on the introduction path side flows to the heat exchanger on the exhaust path side and the second heat exchanger on the introduction path side via the compressor. The outdoor air handling air conditioner according to claim 1.

3. The control device increases the ratio of the flow rate of the refrigerant in the exhaust path heat exchanger to the flow rate of the second inlet path heat exchanger as the temperature of the outside air flowing into the introduction path increases. The outdoor air treatment air conditioner according to claim 2.

4. The exhaust path is further provided with a evaporator located upstream of the exhaust path side heat exchanger, which evaporates the condensed water generated in the first inlet path side heat exchanger. An outdoor air treatment air conditioner according to claim 2 or 3.

5. The enclosure is configured such that the intake path and the exhaust path are adjacent to each other with the inner wall of the enclosure in between, and the airflow in the intake path and the airflow in the exhaust path are in opposite directions. The bypass path is formed by a through-hole that penetrates the inner wall of the housing and whose direction of penetration is obliquely downstream with respect to the airflow direction of the intake path and the exhaust path. The outdoor air handling air conditioner according to claim 1.

6. The exhaust path side heat exchanger comprises a first exhaust path side heat exchanger and a second exhaust path side heat exchanger arranged in parallel in the direction of airflow in the exhaust path. When the control device performs defrosting operation during heating when the exhaust path side heat exchanger acts as an evaporator, it configures the refrigerant circuit so that the first exhaust path side heat exchanger and the second exhaust path side heat exchanger are defrosted alternately. The outdoor air handling air conditioner according to claim 1.

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