JP2020197320A - Air conditioner - Google Patents

Abstract

To improve comfort in an air-conditioning target space.SOLUTION: An air conditioning device 100 includes a compressor 1, a first heat exchanger 5, a second heat exchanger 2, a first expansion valve 4 and a first air blower 6. The first heat exchanger 5 is disposed in a target space. The second heat exchanger 2 is disposed outside the target space. The first air blower 6 sends air to the first heat exchanger 5. Air blowing amount per unit time of the first air blower 6 when a comfort index calculated by using a temperature Tn and humidity Hn of the target space is larger than a reference value is larger than that per unit time of the first air blower 6 when the comfort index is smaller than the reference value.SELECTED DRAWING: Figure 1

Description

The present invention relates to an air conditioner that cools and dehumidifies an air-conditioned space.

Conventionally, an air conditioner that cools and dehumidifies the target space for air conditioning has been known. For example, Japanese Patent No. 4670935 (Patent Document 1) discloses an air conditioner that switches an operation mode according to a sensible heat load and a latent heat load. According to the air conditioner, the temperature and humidity in the air-conditioned area can be brought into a desired state in a short time without waste.

Japanese Patent No. 4670935

The comfort of the space can vary depending on the process of air conditioning in which the temperature and humidity of the space to be air-conditioned approaches the desired temperature and humidity. However, in the air conditioner disclosed in Patent Document 1, the comfort of the space to be air-conditioned in the process of air-conditioning is not considered. As a result, the user's satisfaction with the air conditioner may not be sufficiently obtained.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to improve the comfort of an air-conditioned target space.

The air conditioner according to the present invention air-conditions the target space by circulating a refrigerant. The air conditioner includes a compressor, a first heat exchanger, a second heat exchanger, a first expansion valve, and a first blower. The first heat exchanger is arranged in the target space. The second heat exchanger is located outside the target space. The first blower blows air to the first heat exchanger. The refrigerant circulates in the first circulation direction of the compressor, the second heat exchanger, the first expansion valve, and the first heat exchanger. The amount of air blown per unit time of the first blower when the comfort index calculated using the temperature and humidity of the target space is larger than the reference value is the first blower when the comfort index is smaller than the reference value. It is larger than the amount of air blown per unit time.

According to the present invention, the amount of air blown per unit time of the first blower when the comfort index is larger than the reference value is smaller than the reference value, and the amount of air blown per unit time of the first blower device. By making it larger than the air volume, it is possible to improve the comfort of the target space for air conditioning.

It is a functional block diagram which shows the structure of the air conditioner which concerns on Embodiment 1. FIG. It is a functional block diagram which shows the structure of the control device of FIG. It is a flowchart for demonstrating the operation mode switching process performed by the control device of FIG. It is a psychrometric chart which shows the state change of the air of an indoor space in the process of air conditioning. It is a psychrometric chart which shows the state change of the air of an indoor space when the start state of air conditioning is included in the area of "warning" by WBGT. It is a psychrometric chart which shows the state change of the air of an indoor space in the other process of air conditioning when the WBGT includes the start state of air conditioning in the "danger" area. It is a functional block diagram which also shows the structure of the air conditioner which concerns on Embodiment 2 and the flow of the refrigerant in a cooling operation. It is a figure which also shows the structure of the air conditioner which concerns on Embodiment 2 and the flow of the refrigerant in the reheat dehumidification operation. It is a figure which shows the structure of the air conditioner which concerns on Embodiment 3 and the flow of the refrigerant in a cooling operation. It is a figure which shows the structure of the air conditioner which concerns on Embodiment 3 and the flow of the refrigerant in the reheat dehumidification operation. It is a figure which also shows the structure of the air conditioner which concerns on Embodiment 3 and the flow of the refrigerant in a heating operation.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In principle, the same or corresponding parts in the drawings are designated by the same reference numerals and the description is not repeated.

Embodiment 1.
FIG. 1 is a functional block diagram showing the configuration of the air conditioner 100 according to the first embodiment. As shown in FIG. 1, the air conditioner 100 includes an indoor unit 110 and an outdoor unit 120.

The indoor unit 110 includes an indoor heat exchanger 5 (first heat exchanger), an indoor fan 6 (first blower), a temperature sensor Ts, and a humidity sensor Hs. The indoor unit 110 is arranged in an indoor space (target space) that is the target of air conditioning by the air conditioner 100.

The outdoor unit 120 includes a compressor 1, an outdoor heat exchanger 2 (second heat exchanger), an outdoor fan 3 (second blower), an expansion valve 4 (first expansion valve), and a control device 10. including. The outdoor unit 120 is arranged in an outdoor space outside the indoor space. The control device 10 may be arranged in the indoor unit 110, or may be provided separately from the indoor unit 110 and the outdoor unit 120.

The refrigerant circulates in the circulation direction (first circulation direction) of the compressor 1, the outdoor heat exchanger 2, the expansion valve 4, and the indoor heat exchanger 5. The outdoor heat exchanger 2 functions as a condenser. The refrigerant passing through the outdoor heat exchanger 2 releases heat of condensation into the outdoor space. The indoor heat exchanger 5 functions as an evaporator. The refrigerant passing through the indoor heat exchanger 5 absorbs heat of vaporization from the air around the indoor heat exchanger 5. When the temperature (evaporation temperature) of the refrigerant is lower than the dew point temperature of the air in the indoor space, the moisture in the air around the indoor heat exchanger 5 is liquefied. The air conditioner 100 cools and dehumidifies the indoor space so that the temperature Tn and the humidity Hn of the indoor space approach the desired temperature (set temperature) and the desired humidity (set humidity) set by the user. I do.

The cooling operation by the air conditioner 100 lowers the temperature of the air in the indoor space and removes the sensible heat of the air. The dehumidifying operation by the air conditioner 100 reduces the amount of moisture in the air by changing the state of the moisture in the air in the indoor space to a liquid, and removes the latent heat of the moisture in the air.

By controlling the drive frequency of the compressor 1, the control device 10 controls the amount of refrigerant discharged by the compressor 1 per unit time. In the control device 10, the pressure difference between the refrigerant discharged from the compressor 1 and before being decompressed by the expansion valve 4 and the refrigerant before being decompressed by the expansion valve 4 and sucked into the compressor 1 is a value in a desired range. The opening degree of the expansion valve 4 is controlled so as to be. The expansion valve 4 may be controlled so that the degree of superheating and the degree of supercooling of the refrigerant become target values.

The control device 10 controls the amount of air blown by the outdoor fan 3 per unit time by controlling the rotation speed of the outdoor fan 3. The control device 10 adjusts the amount of heat exchanged between the refrigerant and the air in the outdoor heat exchanger 2 by controlling the outdoor fan 3. The control device 10 controls the amount of air blown per unit time of the indoor fan 6 by controlling the rotation speed of the indoor fan 6. The control device 10 controls the indoor fan 6 to adjust the amount of heat exchange between the refrigerant and the air in the indoor heat exchanger 5. The control device 10 performs a dehumidifying operation on the indoor space by reducing the amount of air blown per unit time of the indoor fan 6 to make the evaporation temperature of the refrigerant lower than the dew point temperature of the indoor air.

The control device 10 acquires the temperature Tn and the humidity Hn of the indoor space from the temperature sensor Ts and the humidity sensor Hs arranged in the indoor space for each sampling time, respectively. Humidity Hn measured by the humidity sensor Hs is relative humidity. The humidity acquired by the control device 10 from the humidity sensor Hs may be absolute humidity. The control device 10 integrally controls the air conditioner 100 so that the temperature Tn and the humidity Hn approach the set temperature and the set humidity.

FIG. 2 is a functional block diagram showing the configuration of the control device 10 of FIG. As shown in FIG. 2, the control device 10 includes a processing circuit 11, a memory 12, and an input / output unit 13. The processing circuit 11 may be dedicated hardware or a CPU (Central Processing Unit) that executes a program stored in the memory 12. When the processing circuit 11 is dedicated hardware, the processing circuit 11 may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), or an FPGA (Field). Programmable Gate Array), or a combination of these. When the processing circuit 11 is a CPU, the function of the control device 10 is realized by software, firmware, or a combination of software and firmware. The software or firmware is described as a program and stored in the memory 12. The processing circuit 11 reads and executes the program stored in the memory 12. The memory 12 includes a non-volatile or volatile semiconductor memory (for example, RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), or EEPROM (Electrically Erasable Programmable Read Only Memory). )), And includes magnetic discs, flexible discs, optical discs, compact discs, mini discs, or DVDs (Digital Versatile Discs). The CPU is also called a central processing unit, a processing unit, an arithmetic unit, a microprocessor, a microcomputer, a processor, or a DSP (Digital Signal Processor).

In general, it is often easier for a user in an indoor space to feel a change in the temperature of the air in the indoor space than a change in the humidity in the indoor space. Further, after starting the air conditioner 100, it takes a certain amount of time until the evaporation temperature of the refrigerant becomes equal to or lower than the dew point temperature of the air around the indoor heat exchanger 5 and the dehumidifying operation becomes possible. Therefore, in the air conditioner 100, when the comfort of the indoor space is relatively low, the cooling of the air in the indoor space is prioritized over the dehumidification of the air. Since the comfort of the indoor space is quickly improved in the process of air conditioning, the comfort of the indoor space can be improved.

In the air conditioner according to the embodiment, the decrease in the comfort of the indoor space is detected by using the comfort index calculated by using the temperature and humidity of the indoor space. Examples of the comfort index include a discomfort index DI (Discomfort Index), a new standard effective temperature SET * (Standard Effective Temperature), and a wet-bulb globe temperature WBGT (Wet Bulb Globe Temperature).

The discomfort index DI is a subjective and empirical comfort index that can comprehensively evaluate the temperature and humidity of the indoor space, and is expressed by the following formula (1).

In equation (1), the variables T and RH represent the temperature (° C.) and relative humidity (%) of air, respectively. The temperature T and the relative humidity RH correspond to the temperature Tn and the humidity Hn in the indoor space, respectively.

The new standard effective temperature SET * (Standard Effective Temperature) is a comfort index adopted as a standard sensible temperature in ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers). The new standard effective temperature SET * is calculated using the temperature, humidity, wind speed, radiant temperature, and the amount of clothing worn by the user in the indoor space.

The wet-bulb globe temperature WBGT is a comfort index devised for the prevention of heat stroke and is represented by the following formula (2).

In the formula (2), the variables T and RH represent the temperature (° C.) and the relative humidity (%) of the air, respectively, as in the formula (2). The variables SR and WS represent the total amount of solar radiation (kW / m ² ) and the average wind speed (m / s), respectively. The total solar radiation amount SR is determined using, for example, data published by a research institution or a public institution (for example, numerical weather prediction data of the Japan Meteorological Agency), or a value measured in an indoor space by an infrared sensor. The average wind speed WS is calculated using the rotation speed of the indoor fan 6. At the start of air conditioning by the air conditioner 100, the indoor fan 6 is stopped, so the average wind speed WS becomes 0.

According to the guidelines for preventing heat stroke in daily life published by the Japanese Soc of Biometeorology, there is a risk of heat stroke occurring in all daily activities when the WBGT in the indoor space exceeds 28 ° C. Specifically, a living environment with a WBGT of less than 25 ° C is judged to be "caution", a living environment with a WBGT in the range of 25 ° C or more and less than 28 ° C is judged to be "warning", and a WBGT is judged to be 28 ° C or more and less than 31 ° C. Living environments within the range of are judged to be "strict caution", and living environments with a WBGT of 31 ° C or higher are judged to be "dangerous". For example, when the WBGT of the indoor space is 29 ° C. in summer, it is necessary to immediately improve the comfort actually felt by the user in the indoor space in order to reduce the risk of heat stroke to a safe level.

In the air conditioner 100, when the WBGT is higher than 25 ° C. (reference value), air conditioning is performed in the comfort priority mode that rapidly lowers the WBGT in the indoor space. Be selected. When the WBGT is lower than 25 ° C., air conditioning is performed in an efficiency priority mode that allows the temperature and humidity of the indoor space to reach the set temperature and humidity as quickly as possible.

When the comfort index is larger than the reference value, the operation mode is switched in the order of comfort priority mode and efficiency priority mode in the process of air conditioning to bring the temperature and humidity of the indoor space closer to the set temperature and humidity, respectively. It is easier for the user to feel the improvement in comfort than if the efficiency priority mode was set from the beginning of the process. According to the air conditioner 100, the comfort of the indoor space is improved, so that the user's satisfaction with the air conditioner 100 can be improved.

FIG. 3 is a flowchart for explaining the operation mode switching process performed by the control device 10 of FIG. The process shown in FIG. 3 is called for each sampling time by a main routine (not shown) that controls the air conditioner 100 in an integrated manner. In the following, the step is simply referred to as S.

As shown in FIG. 3, the control device 10 acquires the temperature Tn and the humidity Hn of the indoor space from the temperature sensor Ts and the humidity sensor Hs in S101, respectively, and proceeds to the process in S102. The control device 10 calculates the comfort index using the temperature Tn and the humidity Hn in S102, and proceeds to the process in S103. The control device 10 determines whether or not the comfort index is larger than the reference value in S103. When the comfort index is larger than the reference value (YES in S103), the control device 10 sets the operation mode to the comfort priority mode in S104 and returns the process to the main routine. When the comfort index is equal to or less than the reference value (NO in S103), the control device 10 sets the operation mode to the efficiency priority mode in S105 and returns the process to the main routine.

The amount of air blown per unit time of the indoor fan 6 in the comfort priority mode is larger than the amount of air blown per unit time of the indoor fan 6 in the efficiency priority mode. In the comfort priority mode, the air cooled by the indoor heat exchanger 5 is blown into the room in a relatively short time, so that the decrease in the evaporation temperature of the refrigerant is suppressed and the cooling by the indoor heat exchanger 5 is performed indoors. It is easily reflected in the temperature of the space. That is, in the comfort priority mode, cooling takes precedence over dehumidification. In the efficiency priority mode, cooling and dehumidification are performed so that the temperature and humidity of the room air reach the set temperature and humidity in the shortest possible time.

4 to 6 are psychrometric charts showing changes in the state of air in the indoor space. The set state Cu specified by the set temperature (24 ° C.) and the set humidity (50%) in FIGS. 4 to 6 is the same state. The curves SC shown in FIGS. 4 to 6 are saturation curves showing a state in which the relative humidity is 100%. In FIGS. 4 to 6, the value of WBGT is shown on the saturation curve, and different hatches are attached to the “warning” area, the “strict caution” area, and the “danger” area. The difference between FIGS. 4 to 6 is the start state of air conditioning specified by the temperature Tn and humidity Hn of the indoor space at the start of air conditioning by the air conditioner 100, and the process of air conditioning from the start state to the set state Cu. ..

FIG. 4 shows a case where the start state C11 is included in the region where the WBGT is lower than 25 ° C. The temperature and humidity of the starting state C11 are 27 ° C. and 70%, respectively. In the case shown in FIG. 4, since the urgency to improve the comfort of the indoor space is relatively low, the operation mode of the air conditioner 100 is set to the efficiency priority mode. As shown in FIG. 4, the process of air conditioning by the air conditioner 100 is a linear process directly from the start state C11 to the set state Cu in the psychrometric chart.

FIG. 5 shows a case where the start state C21 is included in the “alert” region where the WBGT is 25 ° C. or higher and lower than 28 ° C. The temperature and humidity of the starting state C21 are 31 ° C. and 60%, respectively. In the case shown in FIG. 5, since the urgency to improve the comfort of the indoor space is relatively high, the operation mode of the air conditioner 100 is first set to the comfort priority mode. As shown in FIG. 5, the process of air conditioning by the air conditioner 100 goes from the start state C21 to the state C22 through a cooling process in a substantially horizontal direction in the psychrometric chart. The temperature and humidity of state C22 are 26 ° C. and 80%. The WBGT in state C22 is less than 25 ° C. In the state C22, the operation mode of the air conditioner 100 is switched to the efficiency priority mode. The air-conditioning process is a linear process from the state C22 to the set state Cu directly.

FIG. 6 shows a case where the start state C31 is included in the “dangerous” region where the WBGT is 31 ° C. or higher. The temperature and humidity of the starting state C31 are 36 ° C. and 60%, respectively. In the case shown in FIG. 6, since the urgency to improve the comfort of the indoor space is relatively high, the operation mode of the air conditioner 100 is first set to the comfort priority mode. As shown in FIG. 6, the process of air conditioning by the air conditioner 100 goes from the start state C31 in the psychrometric chart to the state C32 on the saturation curve SC through a cooling process in a substantially horizontal direction. Since the WBGT in the state C32 is larger than 25 ° C., the comfort priority mode is continued. The process of air conditioning changes from state C32 substantially along the saturation curve SC to state C33. The WBGT in state C33 is less than 25 ° C. In the state C33, the operation mode of the air conditioner 100 is switched to the efficiency priority mode. The process of air conditioning from the state C33 is a linear process directly toward the set state Cu.

As described above, according to the air conditioner according to the first embodiment, the comfort of the target space for air conditioning can be improved.

Embodiment 2.
In the second embodiment, an air conditioner that performs a reheat dehumidification operation will be described. FIG. 7 is a functional block diagram showing the configuration of the air conditioner 200 according to the second embodiment and the flow of the refrigerant in the cooling operation. In the configuration of the air conditioner 200, the control device 10 is replaced with 10A in the configuration of the air conditioner 100 of FIG. 1, and the indoor heat exchanger 7 (third heat exchanger) and the expansion valve 8 (second expansion). It is a configuration in which a valve) is added. Other than these, the same applies, so the description will not be repeated. In addition, in FIG. 7 and FIG. 8, the fully opened expansion valve is shown by a dotted line. The same applies to FIGS. 9 to 11 referred to in the third embodiment.

As shown in FIG. 7, the indoor heat exchanger 7 and the expansion valve 8 are connected in series in this order between the expansion valve 4 and the indoor heat exchanger 5. The indoor heat exchanger 7 is arranged in the indoor space. The control device 10A controls the opening degree of the expansion valve 4, opens the expansion valve 8 fully, and causes the indoor heat exchangers 5 and 7 to function as evaporators.

FIG. 8 is a diagram showing the configuration of the air conditioner 200 according to the second embodiment and the flow of the refrigerant in the reheat dehumidification operation. As shown in FIG. 8, the control device 10A makes the outdoor heat exchanger 2 and the indoor heat exchanger function as condensers by fully opening the expansion valve 4 and controlling the expansion valve 8. In the reheat dehumidification operation, the air cooled and dehumidified by the indoor heat exchanger 5 is warmed by the indoor heat exchanger 7, so that dehumidification can be performed while suppressing a temperature drop.

The control device 10A controls the amount of air blown per unit time of the outdoor fan 3 to adjust the balance between cooling and dehumidification in air conditioning. When increasing the rate of dehumidification in air conditioning, the control device 10A reduces the amount of air blown per unit time of the outdoor fan 3 to suppress the heat of condensation (condensation capacity) released from the outdoor heat exchanger 2. Increases the heat of condensation released from the heat exchanger 7.

As described above, according to the air conditioner according to the second embodiment, the comfort of the target space for air conditioning can be further improved as compared with the first embodiment by the reheat dehumidification operation.

Embodiment 3.
In the third embodiment, the air conditioner that performs the heating operation by switching the circulation direction of the refrigerant to the circulation direction (second circulation direction) opposite to the circulation direction of the cooling operation and the reheat dehumidification operation will be described. 9 and 10 are functional block diagrams showing the configuration of the air conditioner 300 according to the third embodiment. 9 and 10 show the flow of the refrigerant in the cooling operation and the reheat dehumidification operation, respectively. The configuration of the air conditioner 300 is such that the control device 10A is replaced with 10B in the configuration of the air conditioner 200 of FIG. 7, and a four-way valve 9 (flow path switching valve) is added. Other than these, the same applies, so the description will not be repeated.

As shown in FIGS. 9 and 10, the control device 10B controls the four-way valve 9 to communicate the discharge port of the compressor 1 with the outdoor heat exchanger 2, and also communicates the indoor heat exchanger 5 with the compressor. Communicate with the suction port of 1.

FIG. 11 is a diagram showing the configuration of the air conditioner 300 according to the third embodiment and the flow of the refrigerant in the heating operation. As shown in FIG. 11, it is a functional block diagram which shows the structure of the air conditioner 300. The control device 10B controls the four-way valve 9 to communicate the discharge port of the compressor 1 with the indoor heat exchanger 5 and the outdoor heat exchanger 2 with the suction port of the compressor 1. In the heating operation, the indoor heat exchangers 5 and 7 function as condensers, and the outdoor heat exchanger 2 functions as an evaporator.

As described above, according to the air conditioner according to the third embodiment, the comfort of the target space for air conditioning can be improved and the target space can be heated as in the second embodiment.

It is also planned that the embodiments disclosed this time will be appropriately combined and implemented within a consistent range. It should be considered that the embodiments disclosed this time are exemplary in all respects and not restrictive. The scope of the present invention is shown by the scope of claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1 Compressor, 2 Outdoor heat exchanger, 3 Outdoor fan, 4, 8 Expansion valve, 5, 7 Indoor heat exchanger, 6 Indoor fan, 9 Four-way valve, 10, 10A, 10B controller, 11 Processing circuit, 12 Memory , 13 Input / output unit, 100, 200, 300 air conditioner, 110 indoor unit, 120 outdoor unit.

Claims (4)

An air conditioner that air-conditions the target space by circulating refrigerant.
With a compressor,
The first heat exchanger arranged in the target space and
A second heat exchanger arranged outside the target space,
With the first expansion valve
A first blower that blows air to the first heat exchanger is provided.
The refrigerant circulates in the first circulation direction of the compressor, the second heat exchanger, the first expansion valve, and the first heat exchanger.
In the first case where the comfort index calculated using the temperature and humidity of the target space is larger than the reference value, the amount of air blown per unit time of the first air blower is such that the comfort index is greater than the reference value. A small air conditioner that is larger than the amount of air blown per unit time of the first blower in the second case. A third heat exchanger arranged in the target space and into which the refrigerant from the first expansion valve flows in the first circulation direction.
A second blower that blows air to the second heat exchanger,
Further comprising a second expansion valve connected between the third heat exchanger and the first heat exchanger.
In the first case, the second expansion valve is fully opened and the third heat exchanger functions as an evaporator.
In the second case, the first expansion valve is fully opened and the third heat exchanger functions as a condenser.
The air conditioning according to claim 1, wherein the amount of air blown per unit time of the second blower in the first case is larger than the amount of air blown per unit time of the second blower in the second case. Machine. The air conditioner according to claim 1 or 2, further comprising a flow path switching valve that switches the circulation direction of the refrigerant between the second circulation direction opposite to the first circulation direction. The air conditioner according to any one of claims 1 to 3, wherein the comfort index is a wet-bulb globe temperature.

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