JP7296737B2 - Air conditioning system with solar panel cooling function - Google Patents

Description

TECHNICAL FIELD The present invention relates to an air conditioning system with a solar panel cooling function that includes an air conditioner, a solar panel, and a solar panel cooling circuit, and to improving the energy efficiency of the entire air conditioning system.

In Patent Document 1, a heat conduction plate arranged on the back side of a solar panel is brought into contact with a refrigerant pipe, and a liquid refrigerant is flowed through the refrigerant pipe, thereby vaporizing the liquid refrigerant in the refrigerant pipe and generating a heat conduction plate. A heat pump system is described that reduces the temperature of the

Patent Literature 2 describes a configuration in which a coolant flows through a heat exchanger joined to the back surface of an assembly (solar cell array) of solar cell modules, and the coolant is cooled by a cooler installed outdoors.

Japanese Patent Application Laid-Open No. 2005-195187 JP-A-4-127582

In the configurations described in PTL 1 and PTL 2, by cooling the solar panel or solar cell module assembly with a coolant, the temperature of the solar panel including the solar cell module or the like is lowered, and the maximum output can be increased. There is a possibility. However, since the power consumption of the device that circulates the coolant and cools the coolant increases, there is room for improvement in terms of improving the energy efficiency of the entire system including the solar panel and its cooling device.

On the other hand, an air conditioner for cooling the interior of a building generally has high energy efficiency when given a constant load. For this reason, it is conceivable to use an air conditioner to cool the solar panel, but there is room for improvement in terms of improving the energy efficiency of the entire system.

The present invention is an air conditioning system with a solar panel cooling function that has a function of cooling a solar panel in order to improve the energy efficiency of the air conditioner, and is capable of improving the energy efficiency of the entire system. The purpose is to provide an air conditioning system.

An air conditioning system with a solar panel cooling function according to the present invention includes an air conditioner having an air conditioner refrigerant circuit for circulating a refrigerant to an indoor heat exchanger, a compressor, an outdoor heat exchanger, an expansion valve, and each of the above devices; from the outdoor heat exchanger outlet side of the air conditioner refrigerant circuit to the indoor heat exchanger of the air conditioner refrigerant circuit through the solar panel cooling circuit via an electronic control valve A solar panel cooling refrigerant circuit that branches and guides the refrigerant to the outlet side, and a load factor related to the energy efficiency of the air conditioner, which is the load generated in the outdoor heat exchanger with respect to the capacity of the outdoor heat exchanger. and a valve control unit that controls the electronic control valve based on a load factor, which is a ratio, and a temperature characteristic related to the maximum output of the solar panel during power generation.

According to the air conditioning system with solar panel cooling function according to the present invention, the solar panel is cooled using the air conditioner, and based on the load factor of the air conditioner and the temperature characteristic of the solar panel, the electronic control of the refrigerant circuit for cooling the solar panel A control valve is controlled. As a result, the load on the air conditioner increases, the energy efficiency of the air conditioner can be improved, and the maximum output can be increased by lowering the temperature of the solar panel. Therefore, the solar panel can be cooled in a state in which the energy efficiency of the entire system increases according to the load factor of the air conditioner and the temperature characteristics of the solar panel, so the energy efficiency of the entire system can be improved.

In the air conditioning system with a solar panel cooling function according to the present invention, more preferably, the maximum output of the solar panel increases as the temperature of the solar panel decreases, and the valve control unit controls the load factor of the air conditioner. , when the calculated load factor calculated based on the load of the air conditioner is lower than a predetermined load factor that is preset to maximize energy efficiency, the electronic control valve is opened and the calculated load factor is greater than or equal to the predetermined load factor, the electronic control valve is closed.

According to the above configuration, by opening the electronic control valve when the calculated load factor becomes lower than the predetermined load factor that maximizes the energy efficiency, the solar panel is cooled and the maximum output of the solar panel can be increased. Along with this, since the refrigerant branches and flows not only in the refrigerant circuit for the air conditioner but also in the refrigerant circuit for cooling the solar panel, the amount of refrigerant circulating in the air conditioner increases when maintaining the indoor cooling state. As a result, the calculated load factor increases, so that the calculated load factor can be brought closer to the predetermined load factor. As a result, the energy efficiency of the air conditioner can be improved, and the maximum output of the solar panel can be increased, so that the energy efficiency of the entire system can be improved. Further, by closing the electronic control valve when the calculated load factor is greater than or equal to the predetermined load factor, further increase in the calculated load factor can be suppressed, so that the calculated load factor can be easily maintained near the predetermined load factor.

More preferably, in the air conditioning system with solar panel cooling function according to the present invention, the electronically controlled valve is an electronically controlled expansion valve.

According to the above configuration, there is no need to provide an expansion valve in addition to the electronically controlled expansion valve in the refrigerant circuit for cooling the solar panel.

More preferably, the air conditioning system with a solar panel cooling function according to the present invention includes a temperature sensor that detects the temperature of the solar panel, and when the output voltage of the solar panel exceeds a preset allowable maximum output voltage, Alternatively, the electronic control valve is closed when the detected value of the temperature sensor is equal to or lower than the dew point temperature of the ambient air around the solar panel.

According to the above configuration, when the output voltage of the solar panel is equal to or higher than the allowable maximum output voltage, it is possible to prevent the output voltage from further increasing due to the cooling of the solar panel, thereby protecting the electric circuit of the solar panel. In addition, when the temperature of the solar panel is below the dew point temperature of the surrounding air, it is possible to prevent the temperature from further decreasing due to the cooling of the solar panel, and suppress the occurrence of dew condensation, thereby suppressing a decrease in power generation efficiency.

According to the air conditioning system with solar panel cooling function according to the present invention, the energy efficiency of the air conditioner and the energy efficiency of the entire system can be improved.

It is a figure which shows the state which attached the air-conditioning system with a solar panel cooling function of embodiment which concerns on this invention to the building. 1 is a circuit diagram of an air conditioning system with a solar panel cooling function according to an embodiment; FIG. In the embodiment, it is a diagram showing an example of a performance curve representing the relationship between the load factor of the air conditioner and the COP, which is one of the indexes of energy efficiency. In an embodiment, it is a figure showing an example of the temperature characteristic of a solar panel. 4 is a flow chart showing a control method of an electronically controlled valve by a valve control section in an embodiment. Fig. 2 shows an overview of the energy entering and leaving each element when the solar panel is uncooled (a) and cooled (b);

Embodiments of the present invention will be described below with reference to the drawings. The shapes, numbers, and the like described below are examples for explanation, and can be changed as appropriate according to the specifications of the air conditioning system with a solar panel cooling function. In the following description, the same reference numerals are assigned to the same elements in all the drawings. Also, in the explanation in the text, the reference numerals mentioned before are used as necessary.

FIG. 1 is a diagram showing a state in which an air conditioning system 10 with a solar panel cooling function of the embodiment is attached to a building 100. FIG. The air conditioning system 10 with a solar panel cooling function includes an air conditioner 12, a solar panel 30, a solar panel cooling refrigerant circuit 40, and a valve control section 50 (FIG. 2). The air conditioner 12 is used, for example, for cooling and heating a space such as the room of the building 100 . The solar panel 30 is attached on the roof of the building 100 and generates electricity by receiving sunlight. The air conditioning system 10 with solar panel cooling function is hereinafter referred to as system 10 .

The system 10 improves the maximum output of the solar panel 30 by also cooling the solar panel 30 with the refrigerant circulating in the air conditioner 12, and by appropriately switching between cooling and non-cooling of the solar panel 30, the overall system 10 It also improves energy efficiency.

FIG. 2 is a circuit diagram of system 10. As shown in FIG. The air conditioner 12 has an indoor heat exchanger 13 , a compressor 14 , an outdoor heat exchanger 15 , an expansion valve 16 , and an air conditioner refrigerant circuit 20 that circulates refrigerant through these devices 13 , 14 , 15 , and 16 . The air conditioner refrigerant circuit 20 is composed of a plurality of pipes connecting the devices 13 , 14 , 15 , 16 . In FIG. 2 , each pipe of the air conditioner refrigerant circuit 20 is indicated by a thick arrow.

The air conditioner 12 circulates the refrigerant through the indoor heat exchanger 13, the compressor 14, the outdoor heat exchanger 15, and the expansion valve 16 in this order during indoor cooling. The indoor heat exchanger 13 and the expansion valve 16 are arranged inside an indoor unit 17 arranged indoors in the building 100 . The compressor 14 and the outdoor heat exchanger 15 are arranged inside an outdoor unit 18 arranged outside the building 100 .

The indoor heat exchanger 13 performs heat exchange between the refrigerant flowing inside the indoor heat exchanger 13 and the indoor air passing through the indoor heat exchanger 13 during indoor cooling, and is used as an evaporator that evaporates the refrigerant. be done. The indoor air is cooled by the heat exchange, and is blown into the room from the indoor unit 17 as cooling air.

The compressor 14 is connected between the outlet of the indoor heat exchanger 13 and the inlet of the outdoor heat exchanger 15 when the room is cooled, and compresses the refrigerant evaporated in the indoor heat exchanger 13 while compressing the refrigerant in the outdoor heat exchanger 15. send to

The outdoor heat exchanger 15 is used as a condenser to condense the refrigerant by exchanging heat between the refrigerant flowing inside the outdoor heat exchanger 15 and the outside air passing through the outdoor heat exchanger 15 during indoor cooling. be.

The expansion valve 16 is connected between the outlet of the outdoor heat exchanger 15 and the inlet of the indoor heat exchanger 13 during indoor cooling. The expansion valve 16 lowers the pressure and temperature of the refrigerant to make it easier to evaporate.

FIG. 3 shows an example of a performance curve representing the relationship between the load factor of the air conditioner 12 and the COP, which is one index of energy efficiency. A load factor is defined as the ratio of the load generated on the outdoor heat exchanger to the capacity of the outdoor heat exchanger. As shown in FIG. 3, the performance curve of the air conditioner 12 has a maximum value, and the COP is maximum when the load factor LF is LFmax. Also, under normal usage conditions, the annual average cooling air-conditioning load factor of the air conditioner 12 is lower than the load factor LFmax, and the air conditioner 12 is generally operated with poor energy efficiency. In the embodiment, when the calculated load factor LF of the air conditioner 12 is lower than the predetermined load factor LFm at which the energy efficiency is maximized as described later, the refrigerant flowing to the air conditioner 12 is also used for cooling the solar panel 30 described later. . The calculated load factor LF is the ratio between the load generated in the outdoor heat exchanger 15 calculated from the detection information of the temperature sensor, pressure sensor, etc. included in the air conditioner 12 and the preset capacity of the outdoor heat exchanger 15. calculated from As a result, in addition to the air conditioner refrigerant circuit 20, the refrigerant branches and flows through a solar panel cooling refrigerant circuit 40 that cools the solar panel 30, which will be described later. 12 increases, and the calculated load factor LF increases. Therefore, the calculated load factor LF can be brought close to the predetermined load factor LFm, so that the air conditioner 12 can be operated with high efficiency.

FIG. 4 is a diagram showing an example of temperature characteristics of the solar panel 30. As shown in FIG. As shown in FIG. 4, the maximum output (maximum possible output) of the solar panel 30 monotonically decreases, for example, linearly as the temperature of the solar panel 30 (panel temperature) rises. Therefore, for example, the maximum output can be increased when the temperature of the solar panel 30 drops from t1 to t0 (t0<t1).

Solar panel 30 includes a plurality of solar cell modules electrically connected in series. In the solar panel 30, a plurality of series-connected solar cell modules constitute one set, and a plurality of sets of solar cell modules may be connected in parallel.

As shown in FIG. 2, the solar panel cooling refrigerant circuit 40 includes an electronically controlled expansion valve 41, which is an electronically controlled valve, a solar panel cooling circuit 43, and upstream, intermediate, and downstream pipes 44, 45, and 46. contains. The solar panel cooling circuit 43 is arranged, for example, on the side opposite to the light receiving surface of the solar panel 30 and cools the solar panel 30 . Both ends of the upstream pipe 44 are connected between the outlet of the outdoor heat exchanger 15 and the expansion valve 16 in the air conditioner refrigerant circuit 20 and to the inlet of the electronically controlled expansion valve 41 . Below, the electronically controlled expansion valve 41 is described as LEV41.

The opening degree of the expansion valve of the LEV 41 is controlled by the valve control unit 50 . When the degree of opening is 0, the refrigerant from the outdoor heat exchanger 15 is prevented from flowing downstream of the solar panel cooling refrigerant circuit 40 . By increasing the degree of opening, the refrigerant from the outdoor heat exchanger 15 expands at the LEV 41 and then flows downstream of the solar panel cooling refrigerant circuit 40 . Both ends of the intermediate pipe 45 are connected to the outlet of the LEV 41 and the inlet of the solar panel cooling circuit 43 .

Both ends of the downstream pipe 46 ( FIG. 2 ) are connected between the outlet of the solar panel cooling circuit 43 and the outlet of the indoor heat exchanger 13 and the inlet of the compressor 14 in the air conditioner refrigerant circuit 20 . As a result, the solar panel cooling refrigerant circuit 40 passes through the solar panel cooling circuit 43 from the outlet side of the outdoor heat exchanger 15 of the air conditioner refrigerant circuit 20 via the LEV 41 to the indoor heat exchanger 13 of the air conditioner refrigerant circuit 20. The refrigerant is branched and guided to the outlet side. Therefore, the solar panel 30 can be cooled by the low-temperature refrigerant expanded by the LEV 41 flowing through the solar panel cooling circuit 43 . A mode for cooling the solar panel 30 (solar panel cooling mode) is executed by opening (valve opening) the LEV 41 by the valve control unit 50 .

The valve control unit 50 controls the opening of the LEV 41 based on the load factor of the air conditioner 12 and the relationship between the temperature of the solar panel 30 and the maximum output, which is the temperature characteristic of the solar panel 30 during power generation. The valve control unit 50 includes a microcomputer having a CPU as an arithmetic processing unit and a storage unit such as ROM and RAM.

The system 10 further includes a panel temperature sensor 47 that detects the temperature of the solar panel 30, an outside air temperature sensor 48 that detects the temperature of the air surrounding the solar panel 30, and a humidity sensor 49 that detects the humidity of the surrounding air. . Detection signals from the sensors 47 , 48 , 49 are sent to the valve control section 50 . The valve control unit 50 also controls the opening of the LEV 41 based on detection signals from the sensors 47 , 48 , 49 . In this control, the case where the output voltage of the solar panel 30 becomes equal to or higher than the preset allowable maximum output voltage in terms of protection of the electric circuit of the solar panel 30 is defined as the first case. Also, the dew point temperature of the air around the solar panel 30 is calculated from the values detected by the outside air temperature sensor 48 and the humidity sensor 49 . At this time, the case where the detected value of the panel temperature sensor 47 is equal to or less than the calculated value of the dew point temperature is defined as the second case. The valve control unit 50 closes the LEV 41 in the first case or the second case to stop the solar panel cooling mode.

A method of controlling the LEV 41 using the valve control unit 50 will be described with reference to FIG. FIG. 5 is a flowchart showing a method of controlling the LEV 41 by the valve control section 50. As shown in FIG. The processing shown in FIG. 5 is executed by the valve control unit 50. As shown in FIG. When the system 10 is powered on and the valve control unit 50 is activated, first, in step S11, it is determined whether or not the calculated load factor LF of the air conditioner 12 is 0, that is, whether or not the air conditioner 12 is stopped. be done. When the air conditioner 12 is stopped (determination in step S11 is YES), the process proceeds to step S16, and when the air conditioner 12 is in operation (determination in step S11 is NO), the process proceeds to step S12. do. At step S16, the LEV 41 is closed to stop the solar panel cooling mode. After completing the process of step S16, the process returns to step S11.

In step S12, it is determined whether or not the output voltage Vp of the solar panel 30 is equal to or higher than the allowable maximum output voltage Vpm (Vp≧Vpm). The determination process in step S12 is performed to protect the electric circuit of the solar panel 30 by stopping the cooling of the solar panel 30 when the output voltage of the solar panel 30 is too high.

When the output voltage Vp of the solar panel 30 is less than the allowable maximum output voltage Vpm (when the determination in step S12 is NO), the process proceeds to step S13.

In step S13, it is determined whether or not the temperature Tp of the solar panel 30, which is the value detected by the panel temperature sensor 47, is equal to or lower than the dew point temperature Td of the ambient air around the solar panel 30 (Tp≤Td). In the determination process of step S13, when the temperature Tp of the solar panel 30 is equal to or lower than the dew point temperature Td of the surrounding air, cooling of the solar panel 30 is stopped to prevent the temperature of the solar panel 30 from further decreasing. This is performed to suppress a decrease in power generation efficiency of the solar panel 30 due to the occurrence of dew condensation.

When the temperature Tp of the solar panel 30 exceeds the dew point temperature Td of the ambient air (when the determination in step S13 is NO), the process proceeds to step S14.

Next, in step S14, the calculated load factor LF, which is the ratio of the load generated in the outdoor heat exchanger 15 to the capacity of the outdoor heat exchanger 15, is set to a predetermined load factor LFm that is preset so as to maximize the energy efficiency. It is determined whether or not (LF≧LFm). As described above, the calculated load factor LF is the load generated in the outdoor heat exchanger 15 calculated from the detection information of the temperature sensor, the pressure sensor, etc. included in the air conditioner 12, and the preset outdoor heat exchanger 15 It is calculated from the ratio with the capacity of When the calculated load factor LF is lower than the predetermined load factor LFm (when the determination in step S14 is NO), the process proceeds to step S15.

In step S15, the LEV 41 is opened and the solar panel cooling mode is executed. After the process of step S15, the process returns to step S11.

On the other hand, if the determinations in steps S12, S13, and S14 are YES, the process proceeds to step S16 and the LEV 41 is closed, as in the case of the determination in step S11 being YES. The order of the processing of steps S11 to S14 in FIG. 5 may be changed.

According to the above system 10, the air conditioner 12 is used to cool the solar panel 30, and the load factor related to the energy efficiency of the air conditioner 12 and the temperature characteristic related to the maximum output of the solar panel 30 during power generation Based on this, the LEV 41 on the refrigerant upstream side of the solar panel cooling circuit 43 is controlled. As a result, the load on the air conditioner 12 increases, the energy efficiency of the air conditioner 12 can be improved, and the maximum output can be increased by lowering the temperature of the solar panel 30 . Therefore, since the solar panel 30 can be cooled while the energy efficiency of the entire system is high, the energy efficiency of the entire system can be improved. Moreover, it is not necessary to prepare a cooling medium (such as water) other than the air conditioner 12 for cooling the solar panel 30 . This eliminates the need to prepare a power source or the like for flowing the cooling medium, and also eliminates the need to manage the quality.

Here, the energy efficiency of the entire system can be defined as follows. FIG. 6 summarizes the energy entering and leaving each element of the solar panel 30 when it is uncooled (a) and cooled (b). Let Cac, Qac, and Gac be the power consumption of the air conditioner 12, the cooling capacity, and the output of the solar panel 30 when the solar panel 30 is not cooled, respectively. At this time, the energy efficiency E1 of the entire system is defined by E1=Qac/Cac.

On the other hand, when the solar panel 30 is cooled, if the solar panel 30 is cooled with the cooling capacity DQ of the air conditioner 12 that can be used for cooling the solar panel 30, it is assumed that the cooling increases the output of the solar panel 30 by DG. do. In this case, the power consumption of the air conditioner 12, the cooling capacity, and the output of the solar panel 30 are Cpv (=Cac+DC), Qpv (=Qac+DQ), and Gpv (=Gac+DG), respectively. At this time, the energy efficiency E2 of the entire system is defined as E2=Qac/(Cpv-DG).

Since the above formula can be transformed into E2=Qac/{Cac-(DG-DC)}, if the output DG, which increases due to the cooling of the solar panel 30, exceeds the increase in the power consumption of the air conditioner 12, DC , the cooling of the solar panel 30 allows the overall system energy efficiency E2 to be higher than E1. According to the above embodiment, the solar panel 30 can be cooled such that the energy efficiency E2 of the entire system is higher than E1. This will be explained later using trial calculation results.

Furthermore, the maximum output of the solar panel 30 increases as the temperature of the solar panel 30 decreases. It is controlled to open LEV41. Thus, by opening the LEV 41 when the calculated load factor LF is lower than the predetermined load factor LFm, the solar panel 30 is cooled and the maximum output can be increased. Along with this, since the refrigerant branches and flows through the solar panel cooling refrigerant circuit 40 in addition to the air conditioner refrigerant circuit 20, the amount of refrigerant circulating in the air conditioner 12 increases when maintaining the indoor cooling state. . Therefore, the calculated load factor LF can be increased so as to approach the predetermined load factor LFm. As a result, the energy efficiency of the air conditioner 12 can be improved, and the maximum output of the solar panel 30 can be increased, so that the energy efficiency of the entire system can be improved. In addition, since the LEV 41 is controlled to be closed when the calculated load factor LF becomes equal to or higher than the predetermined load factor LFm, further increase in the calculated load factor LF can be suppressed, and the load factor LF can be easily maintained near the predetermined load factor LFm.

Furthermore, since the electronically controlled valve controlled by the valve control unit 50 is the LEV 41 , there is no need to provide an expansion valve in addition to the LEV 41 in the solar panel cooling refrigerant circuit 40 . The electronic control valve controlled by the valve control unit 50 may be an electronic on-off valve provided in the solar panel cooling refrigerant circuit 40, and an expansion valve may be provided downstream of the electronic on-off valve. , the number of parts increases, unlike the above embodiment.

Further, the valve control unit 50 is controlled when the output voltage of the solar panel 30 is equal to or higher than the preset allowable maximum output voltage, or when the detected value of the panel temperature sensor 47 is lower than the dew point temperature of the air surrounding the solar panel 30. If so, LEV 41 is closed. As a result, when the output voltage of the solar panel 30 is equal to or higher than the allowable maximum output voltage, it is possible to prevent the output voltage from further increasing due to the cooling of the solar panel 30, thereby protecting the electric circuit of the solar panel 30. At the same time, when the solar panel 30 is below the dew point temperature of the surrounding air, the cooling of the solar panel 30 prevents the temperature from further decreasing, and suppresses the occurrence of dew condensation, thereby suppressing the decrease in power generation efficiency. .

It should be noted that to determine whether the detected value of the panel temperature sensor 47 is equal to or lower than the dew point temperature of the air surrounding the solar panel 30, instead of the outside air temperature sensor 48 and the humidity sensor 49, A dew point temperature sensor may be used to detect the In this case, the valve control unit 50 determines whether the temperature of the solar panel 30 is equal to or lower than the dew point temperature of the ambient air based on the detected value of the dew point temperature sensor and the detected value of the panel temperature sensor 47 .

In the control method shown in FIG. 5, the processing of steps S12 and S13 can be omitted. If step S12 is omitted, for example, the electric circuit of the solar panel 30 is protected by means other than the processing of step S12.

Next, as in the embodiment, it is confirmed that it is efficient to cool the solar panel 30 by the air conditioner 12 so that the load factor of the air conditioner 12 approaches the load factor that maximizes the energy efficiency. I will explain the results of the trial calculations performed for this purpose.

Trial calculations were made by setting a specific place and time (May) and assuming outdoor and indoor conditions. The trial calculation was made under the condition that the valve control unit 50 controls the LEV 41 so that the calculated load factor LF of the air conditioner 12 approaches the predetermined load factor LFm (=25.0%). At the predetermined load factor LFm, the COP, which is one index of energy efficiency, is maximized in the air conditioner 12 .

At this time, in the rated cooling operation of the air conditioner 12, the operation in the average state at the average temperature and average humidity in May (average operation), and the operation when the COP is maximum (COP maximum operation), the air conditioner The cooling capacity, power consumption, and COP (or COP ratio) of 12 were calculated as shown in Table 1.

In Table 1, COP is calculated by COP=(cooling capacity)/(power consumption). The COP ratio is the ratio of the COP in May average operation or COP maximum operation to the COP in rated cooling operation with a load factor of 85.0%.

At this time, the cooling capacity of the air conditioner 12 that can be used for cooling the solar panel 30 is calculated from Table 1 by the following equation (1).

(Cooling capacity at maximum COP operation) - (cooling capacity at average operation in May) = 2.14 - 1.43 = 0.71 (kW) (1)

Also, in the air conditioner 12, the power consumption that increases due to the cooling of the solar panel 30 is calculated from Table 1 by the following equation (2).

(Power consumption at maximum COP operation) - (Power consumption at average operation in May) = 0.189 - 0.132 = 0.057 (kW) (2)

Also, the temperature of the solar panel 30 decreases until the amount of heat Qair given from the ambient air becomes equal to the amount of heat Qref taken away by the coolant. When the solar panel 30 is uncooled, the heat quantity Qair (=Qref)=0, and when the solar panel 30 is cooled, the heat quantity Qair (=Qref)>0. From the formula (1), the heat quantity Qair (=heat quantity Qref) is 0.71 kW.

Other conditions in the trial calculation are as follows.
Air temperature in May: 25.1°C
Assumed temperature of solar panel 30 cooled by air conditioner 12: 15.0°C
Heat transfer coefficient: 5.0 W/m ² K
Maximum output per solar cell module constituting the solar panel 30: 275 W

Under the above conditions, the area of the solar panel 30 for the heat quantity Qair to be 0.71 kW was calculated, and when the area was converted into the number of solar cell modules, the number was 8.5.

As a result, when it is assumed that the cooling operation of the solar panel 30 is started and the temperature of the solar panel 30 drops to 15° C. with the cooling capacity (=0.71 kW) of the air conditioner 12 that can be used for cooling the solar panel 30. , the number of solar cell modules that can be cooled was found to be 8.5. It is also known that the maximum output of the solar panel 30 increases by 5% when the temperature drops by 10°C. Therefore, the maximum output of the solar panel 30, which is increased by cooling the solar panel 30, is 0.01375 kW per solar cell module. .117 kW. As a result, the total maximum output increased by cooling the solar panel 30 was calculated to be 0.117 kW.

This calculated value (0.117 kW) exceeds the power consumption (0.057 kW) of the air conditioner 12 that increases due to the cooling of the solar panel 30 obtained by the formula (2). As a result, it was confirmed that the output DG ( FIG. 6 ) of the solar panel 30 that increases due to cooling by the air conditioner 12 exceeds the power consumption DC ( FIG. 6 ) of the air conditioner 12 that increases due to cooling of the solar panel 30 . Therefore, it was confirmed that by cooling the solar panel 30, the energy efficiency E2 can be made higher than the energy efficiency E1 when the solar panel 30 is not cooled. As a result, considering the increase in power consumption of the air conditioner 12, it is efficient to cool the solar panel 30 so that the load factor of the air conditioner 12 approaches the load factor that maximizes the energy efficiency. I was able to confirm that.

Note that a plurality of solar panel cooling refrigerant circuits may be connected to the air conditioner refrigerant circuit.

10 Air conditioning system with solar panel cooling function (system), 12 Air conditioner, 13 Indoor heat exchanger, 14 Compressor, 15 Outdoor heat exchanger, 16 Expansion valve, 17 Indoor unit, 18 Outdoor unit, 20 Refrigerant circuit for air conditioner , 30 solar panel, 40 solar panel cooling refrigerant circuit, 41 electronically controlled expansion valve (LEV), 43 solar panel cooling circuit, 44 upstream piping, 45 intermediate piping, 46 downstream piping, 47 panel temperature sensor, 48 outside air temperature sensor, 49 humidity sensor, 50 valve controller, 100 building.

Claims (4)

an air conditioner having an indoor heat exchanger, a compressor, an outdoor heat exchanger, an expansion valve, and an air conditioner refrigerant circuit for circulating the refrigerant to each of the devices;
a solar panel that converts sunlight into electricity;
Refrigerant is branched and guided from the outdoor heat exchanger outlet side of the air conditioner refrigerant circuit to the indoor heat exchanger outlet side of the air conditioner refrigerant circuit through the cooling circuit of the solar panel via an electronic control valve. a refrigerant circuit for cooling the solar panel;
A load factor related to the energy efficiency of the air conditioner, which is the ratio of the load generated in the outdoor heat exchanger to the capacity of the outdoor heat exchanger, and the maximum output of the solar panel during power generation a valve control unit that controls the electronically controlled valve based on related temperature characteristics;
with
closing the electronic control valve when the output voltage of the solar panel is equal to or higher than a preset allowable maximum output voltage;
Air conditioning system with solar panel cooling function. In the air conditioning system with solar panel cooling function according to claim 1,
The maximum output of the solar panel increases as the temperature of the solar panel decreases,
The valve control unit controls the load factor of the air conditioner when the calculated load factor calculated based on the load of the air conditioner becomes lower than a predetermined load factor that is preset so as to maximize energy efficiency. and controlling to open the electronic control valve and to close the electronic control valve when the calculated load factor is greater than or equal to the predetermined load factor;
Air conditioning system with solar panel cooling function. In the air conditioning system with solar panel cooling function according to claim 1 or claim 2,
wherein the electronically controlled valve is an electronically controlled expansion valve;
Air conditioning system with solar panel cooling function. In the air conditioning system with solar panel cooling function according to any one of claims 1 to 3,
A temperature sensor that detects the temperature of the solar panel ,
closing the electronic control valve when the detected value of the temperature sensor is equal to or lower than the dew point temperature of the air surrounding the solar panel;
Air conditioning system with solar panel cooling function.

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