JPH0682083A - Defrosting control device for heat pump type air-conditioner - Google Patents

Abstract

PURPOSE:To perform a defrosting operation with an approximately fixed frosting quantity not only to the variation of the outside temperature but also to the variations of the capacity of a compressor or indoor air blowing quantity, and improve the efficiency and amenity. CONSTITUTION:The defrosting control device is equipped with an outside temperature detecting means 8a which detects the outside temperature, an outside humidity detecting means 9 which detects the outside humidity, a capacity detecting means 13 which detects the capacity of a capacity variable type compressor 1, and a blowing air volume detecting means 12 which detects the blow air volume of an indoor blowing means 6 being provided in the vicinity of an indoor side heat exchanger 3, and an operation is performed using the detected values by these detecting means with a specified cycle, and when an integrated value which is obtained by an operation means 14, which performs the integration of the operation result for each specified cycle, becomes a specified value, the defrosting of an outdoor side heat exchanger 5 is performed by a defrosting means 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defrost control device for a heat pump type air conditioner using air as a heat source.

[0002]

2. Description of the Related Art In a heat pump type air conditioner, frost formation may occur in the outdoor heat exchanger during heating operation to reduce the amount of heat absorbed from the outside air. It is necessary to detect and perform defrosting operation.

As a conventional defrosting control method, the temperature of the outdoor heat exchanger is detected by a temperature detecting element, and a predetermined time or more has elapsed after the start of the heating operation or the end of the previous defrosting operation, and When the temperature of the outdoor heat exchanger detected by the detection element is lower than or equal to a predetermined value, the defrosting operation is generally performed by determining that the outdoor heat exchanger has frosted.

However, in this method, when the operation is performed when the outside air temperature is low, the temperature of the outdoor heat exchanger is always below the predetermined value, so that the relative humidity of the outdoor air is low and the outdoor heat exchanger is frosted. Even without it, unnecessary defrosting operation is performed every predetermined time, resulting in deterioration of efficiency and comfort.

In order to improve this, the outside air temperature and the relative humidity are detected to determine whether or not it is within the frosting region, and when it is determined to be within the frosting region, the defrosting operation is performed after a predetermined time of operation. There is also known a method of performing the above (for example, Japanese Patent Laid-Open No. 62-1
42944).

Further, there is provided output means for outputting a predetermined value at a predetermined outside air temperature and outside air humidity by using a humidity sensitive element whose resistance value changes in response to a change in outside air temperature and a change in outside air humidity. There is also known a method in which the values output by are integrated and a defrosting operation is performed when the integrated value reaches a predetermined value (for example, Japanese Patent Laid-Open No. 62-129637).

[0007]

However, the above conventional defrosting control system has the following problems.

That is, when the compressor capacity is constant and the amount of air blown by the indoor air blower is constant, it is possible to prevent unnecessary defrosting operation when the outside air temperature is low by using the above conventional technique. However, the speed of frost formation on the outdoor heat exchanger when changing the compressor capacity according to the load by using a variable capacity compressor or when changing the indoor air flow according to the user's preference Could not be detected, and thus unnecessary defrosting operation was also performed, resulting in a decrease in efficiency and comfort.

In view of the above problems, the present invention indirectly obtains the amount of frost formation by using an arithmetic expression that takes into consideration the change in compressor capacity and the change in indoor air flow rate, so that not only the change in outside temperature but also the compressor The purpose is to improve the efficiency and comfort by performing defrosting operation with a substantially constant amount of frosting even with changes in capacity and indoor air flow rate.

[0010]

In order to solve the above problems, a defrost control device for a heat pump type air conditioner according to the present invention comprises a variable capacity compressor, an outdoor heat exchanger, a pressure reducer and an indoor heat exchanger. A refrigerant circuit is configured by sequentially connecting the units in a ring shape with a pipe, and an outside air temperature detecting means for detecting the outside air temperature, an outside air humidity detecting means for detecting the outside air humidity, and a capacity detection for detecting the capacity of the variable capacity compressor. Means and an air blowing amount detecting means for detecting an air blowing amount of an indoor air blowing means provided in the vicinity of the indoor heat exchanger, and a calculation is performed by using values detected by these detecting means at a predetermined cycle, and for each predetermined cycle. It comprises a calculation means for integrating the calculation results and a defrosting means for defrosting the outdoor heat exchanger when the integrated value reaches a predetermined value.

Further, another defrost control device for a heat pump type air conditioner of the present invention is such that a variable capacity compressor, an outdoor heat exchanger, a pressure reducer and an indoor heat exchanger are connected in an annular shape by piping in this order. And a means for outputting a predetermined value at a predetermined outside air temperature and outside air humidity by using a humidity sensitive element whose resistance value changes in response to changes in outside air temperature and outside air humidity. Output detecting means for detecting the value output by the air-conditioning device, capacity detecting means for detecting the capacity of the variable displacement compressor, and air-blowing amount detection for detecting the air-blowing amount of the indoor air-blowing means provided in the vicinity of the indoor heat exchanger. Means and a value detected by these detection means in a predetermined cycle, and a calculation means for performing integration of the calculation results in the predetermined cycle and a removal of the outdoor heat exchanger when the integrated value reaches a predetermined value. Defrosting means for defrosting It is Ranaru thing.

[0012]

The present invention has the following actions due to the above means.

That is, by indirectly calculating the frost formation amount using an arithmetic expression that takes into consideration the change in the compressor capacity and the change in the indoor air flow rate, not only the change in the outside temperature and humidity but also the compressor capacity and the indoor air flow rate The defrosting operation can be performed with a substantially constant amount of frosting even with respect to the change.

Therefore, the defrosting operation is performed even if the outdoor heat exchanger is not frosted, or a large amount of frost is formed and the next heating operation is performed without completely defrosting within a predetermined time. Therefore, it is possible to improve efficiency and comfort.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to FIGS.

FIG. 1 is a refrigeration cycle diagram of a heat pump type air conditioner in a first embodiment of the present invention.

In the figure, 1 is a variable frequency compressor,
2 is a four-way valve, 3 is an indoor heat exchanger, 4 is a pressure reducer, 5 is an outdoor heat exchanger, an indoor fan 6 is provided near the indoor heat exchanger 3, and the outdoor heat exchanger is provided. Outdoor fans 7 are provided in the vicinity of 5, respectively.

In this heat pump type air conditioner,
The refrigerant discharged from the compressor 1 during heating is the four-way valve 2,
The indoor heat exchanger 3, the pressure reducer 4, the outdoor heat exchanger 5, and the four-way valve 2 flow in this order and are sucked into the compressor 1 again. Further, the indoor fan 6 sends warm air into the room for heating.

Further, 8a is a temperature sensor for detecting the outside air temperature, 8b is a temperature sensor for detecting the temperature of the outdoor heat exchanger 5, and 9 is a humidity sensor for detecting the outside air humidity. 10 and the humidity detection circuit 11 read. Further, 12 is an air volume detection circuit for detecting the indoor air flow rate of the indoor fan 6, and 13 is a frequency detection circuit for detecting the frequency of the frequency variable compressor 1.

During the heating operation, the temperature detection circuit 10 determines the outside air temperature and the temperature of the outdoor heat exchanger 5, the humidity detection circuit 11 determines the outside air humidity, and the air flow detection circuit 12 determines the indoor fan at predetermined intervals. 6, and the frequency of the variable frequency compressor 1 is detected by the frequency detection circuit 13, and these signals are sent to the microcomputer 14 to perform a predetermined calculation to calculate the frost formation amount. When the integrated value reaches a predetermined value, a signal is sent from the microcomputer 14 to the defrost control relay 15, the four-way valve 2 is reversed, the indoor fan 6 and the outdoor fan 7 are stopped, and the defrost operation is performed. During the defrosting operation, a signal from the temperature detection circuit 10 is continuously sent to the microcomputer 14 to compare with a predetermined defrosting end temperature, and when the temperature of the outdoor heat exchanger 5 becomes equal to or higher than the defrosting end temperature. A signal is sent to the defrosting control relay 15 to return to the heating operation again.

Next, an arithmetic expression for calculating the amount of frost formation will be described. FIG. 2 shows the outside air temperature when the heat pump type air conditioner according to the present embodiment is heated in a constant operating condition (compressor frequency, indoor fan speed, outdoor fan speed, and throttle amount of the pressure reducer are fixed). And relative humidity and outdoor heat exchanger 5
And the amount of frost per unit time (when the temperature of the outdoor heat exchanger 5 is 0 ° C. or higher, this is the dehumidification amount).
Here, when the outside air temperature is t, the relative humidity is RH, the frosting amount per hour is FR, and A1 to A9 are constants, FR is a relationship between t and RH as shown in FIG. It can be approximated by [Expression 1].

[0022]

[Equation 3]

FIG. 3 is a diagram showing the relationship between the change in the indoor air flow rate and the frost formation rate per unit time under a predetermined outdoor temperature. FIG. 4 shows the relationship between the compressor frequency (compressor capacity) and the frost formation amount per unit time under a predetermined outside air temperature when a variable capacity compressor using an inverter is used. It is a figure.

As is clear from FIG. 3 and FIG. 4, in the practical range, the indoor air blowing amount and the frosting amount and the compressor frequency and the frosting amount are in a substantially proportional relationship.

From the above, the amount of frost can be calculated by the following equation [2] using an arithmetic expression.

[0026]

[Equation 4]

SUM _N : _N = Δτ (minutes) after the start of operation Δτ: Scan interval (minutes) FANi: Indoor air flow rate FANs: Reference indoor air flow rate (calculation of the frost amount shown in FIG. 2) Indoor air flow rate at the time) CMPi: Compressor frequency CMPs: Reference compressor frequency (compressor frequency at the time of calculating the amount of frost formation shown in FIG. 2) FIG. 5 is a flowchart of defrosting control using the above arithmetic expression. is there.

In the figure, th is the temperature of the outdoor heat exchanger 5, FRs is the reference frosting amount (defrosting start frosting amount), tds
Is the temperature of the outdoor heat exchanger 5 determined to be defrosted.

During the heating operation, the above-mentioned detection circuits detect the outside temperature t, the relative humidity RH, the outside heat exchanger temperature th, the compressor frequency CMP, and the indoor air flow rate FAN at predetermined intervals, and th> 0 ° C. Then, since it becomes water, SUM is calculated using the above arithmetic expression only when th ≦ 0 ° C. And SUM ≧ F
When Rs, the defrosting operation is started, and when th ≧ tds, the defrosting operation is terminated, SUM = 0 is set, and the flow returns to the beginning.

Therefore, the defrosting operation can be always performed with a substantially constant frosting amount even when the outside air temperature and humidity and the operating condition change.

Next, a second embodiment of the present invention will be described. FIG. 6 is a refrigeration cycle diagram of the heat pump type air conditioner in the second embodiment of the present invention. Here, in the figure, those having the same functions as those shown in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.

In FIG. 6, reference numeral 16 is provided in the vicinity of the outdoor heat exchanger 5, and a predetermined outside air temperature is obtained by combining a resistance with a humidity sensitive element whose resistance value changes in accordance with changes in the outside air temperature and humidity. Is a frost detection circuit that outputs a predetermined value in the outside air humidity, and 17 is an output detection circuit that detects the output of the frost detection circuit 16 and sends a signal to the microcomputer 14.

FIG. 7 shows an example of the relationship between the outside air temperature, the relative humidity and the output of the frost detection circuit. In this way, the frost detection circuit 1
The output values of 6 with respect to the outside air temperature and outside air humidity can be approximated to the tendency of the frosting characteristics of the heat pump type air conditioner shown in FIG. 2 by a known method.

Therefore, instead of using the approximate expression FR = f (t, RH) of the frost formation shown in the first embodiment, the following expression [3] using the output value OT of the frost detection circuit 16 is used. The amount of frost formation can be calculated.

[0035]

[Equation 5]

Therefore, in the first embodiment, the outside air temperature and the outside air humidity are detected and the frost formation amount per hour is obtained by an approximate expression, whereas in the second embodiment, the output value of the frost formation detection circuit is unchanged. It is possible to perform the calculation by using the defrosting control shown in FIG.

In the first and second embodiments described above, the integration is performed when the temperature of the outdoor heat exchanger is 0 ° C. or lower. However, this value depends on the air volume of the outdoor fan and the size of the heat exchanger. , The fin pitch, etc. may be set arbitrarily.

In addition to the control described in the first and second embodiments, when the temperature of the outdoor heat exchanger is connected a predetermined number of times or more and is a predetermined value or more, the integrated value up to that point is set to 0. By doing so, even if the outside air temperature rises during the operation, or the frost that has once adhered due to the compressor operating in a small capacity melts and then frost forms again, the frost formation amount can be accurately adjusted. It can be calculated.

When the capacity of the compressor is continuously less than a predetermined number of times for a predetermined number of times or more, by adding a control to make the integrated value up to that point to be 0, the room temperature becomes a set value or more in the middle of operation and After the frost has stopped and the frost that has once adhered has melted, the amount of frost formation can be accurately calculated even when the compressor operates again and frost formation progresses.

Further, by providing a defrosting prohibition section in which the defrosting operation is prohibited for a predetermined time from the start of the heating operation and the end of the defrosting operation, regardless of the integrated value, a water drop is formed on the humidity detecting portion such as the humidity sensor. When the amount of frost is calculated to be much larger than the actual value due to the adhesion of the like and the like, and thus the frost formation amount is calculated to be much larger than the actual value, it is possible to prevent the insufficient heating due to frequent defrosting operation.

[0041]

As described above, the defrosting control device for the heat pump type air conditioner of the present invention is capable of controlling outside air temperature, outside air humidity,
By detecting the compressor capacity and indoor air flow rate and calculating the frost formation indirectly by performing calculations using these values, not only changes in outside temperature and humidity but also changes in compressor capacity and indoor air flow rate Also, the defrosting operation can be performed with a substantially constant amount of frost formation. Therefore, the defrosting operation is not performed even if the outdoor heat exchanger is not frosted, or a large amount of frost is formed and the next heating operation is not performed without complete defrosting within the predetermined time. It is possible to improve efficiency and comfort.

Further, the relationship between the compressor capacity and the frost formation amount and the relationship between the indoor air flow amount and the frost formation amount are proportional to each other in the practical range, and the frost formation amount is calculated by a simple arithmetic expression. can do.

Further, instead of detecting the outside air temperature and outside air humidity, a predetermined value is output at a predetermined outside air temperature and outside air humidity by using a humidity sensing element whose resistance value changes according to changes in the outside air temperature and outside air humidity. By detecting the output value of the output means, the output value can be used as it is in the arithmetic expression.

Further, by utilizing the relationship between the output value of the output means, the compressor capacity and the amount of frost formation and the relationship between the indoor air flow rate and the frost formation, the frost formation amount can be calculated by a simpler arithmetic expression. can do.

Further, when the temperature of the outdoor heat exchanger is equal to or higher than a predetermined value, by performing control not to add the calculated value to the accumulated value up to that point, more accurate detection of the amount of frost can be detected.

Further, when the temperature of the outdoor heat exchanger is continuously a predetermined value or more for a predetermined number of times or more, a control is added to make the integrated value up to that time to be 0, whereby the outside air temperature rises during the operation, Alternatively, the frost formation amount can be accurately calculated even when the frost that has once adhered is melted by the small-capacity operation of the compressor and then the frost formation progresses again.

Further, when the compressor capacity is continuously less than a predetermined value for a predetermined number of times or more, control is performed to set the integrated value up to that point to 0 so that the room temperature becomes a set value or more during operation and compression is performed. Even if the compressor stops and the frost that has once adhered is melted and then the compressor is operated again to cause frost formation, the frost formation amount can be accurately calculated.

Further, by providing a defrosting prohibition section in which the defrosting operation is prohibited for a predetermined time from the start of the heating operation and the end of the defrosting operation, regardless of the integrated value, a water drop is formed on the humidity detecting portion such as the humidity sensor. Even if the amount of frost is calculated to be higher than the actual value and the calculated amount of frost is much larger than the actual value, it is possible to prevent the insufficient heating due to frequent defrosting operation.

[Brief description of drawings]

FIG. 1 is a refrigeration cycle diagram of a heat pump type air conditioner according to a first embodiment of the present invention.

FIG. 2 is a characteristic diagram showing the relationship between the outside air temperature, the relative humidity, and the amount of frost formed per unit time.

FIG. 3 is a characteristic diagram showing a relationship between a change in indoor air flow and an amount of frost per unit time.

FIG. 4 is a characteristic diagram showing a relationship between a compressor frequency (compressor capacity) and a frost formation amount per unit time.

FIG. 5 is a flowchart showing an example of defrost control of the defrost control device of the present invention.

FIG. 6 is a refrigeration cycle diagram of the heat pump type air conditioner in the second embodiment of the present invention.

FIG. 7 is a characteristic diagram showing the relationship between the outside air temperature and relative humidity and the output of the frost detection circuit.

[Explanation of symbols]

 1 frequency variable type (variable capacity type) compressor 3 indoor heat exchanger 4 pressure reducer 5 outdoor heat exchanger 6 indoor fan (indoor air blowing means) 8a temperature sensor (outside air temperature detecting means) 8b temperature sensor (heat exchanger Temperature detection means) 9 Humidity sensor (outside air humidity detection means) 10 Temperature detection circuit 11 Humidity detection circuit 12 Air volume detection circuit (air flow rate detection means) 13 Frequency detection circuit (capacity detection means) 14 Microcomputer (calculation means) 15 Defrost Control relay (defrosting means) 16 Frost detection circuit (output means) 17 Output detection circuit (output detection means)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kuniyasu Uchiyama 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. Applied Technology Research Institute (72) Inventor Kenichi Sakurai 7-2 Nakayama 7-chome, Aoba-ku, Sendai City, Miyagi Prefecture Tohoku Electric Power Co., Inc. Applied Technology Research Institute

Claims (9)

[Claims] 1. An outside air temperature detecting means for detecting an outside air temperature by connecting a variable capacity compressor, an outdoor heat exchanger, a decompressor, and an indoor heat exchanger in this order by a pipe to form a refrigerant circuit. And an outside air humidity detecting means for detecting outside air humidity, a capacity detecting means for detecting the capacity of the variable capacity compressor, and an air flow rate for detecting an air flow rate of an indoor air blower provided near the indoor heat exchanger. Detecting means, calculating means for performing calculation using values detected by these detecting means in a predetermined cycle, and integrating the calculation results for each of the predetermined cycles, and the outdoor heat exchange when the integrated value reaches a predetermined value. Defrosting control device for a heat pump type air conditioner, which comprises defrosting means for defrosting the air conditioner. 2. The integrated value from the start of integration to the Nth time, t is the outside temperature, RH is the outside air humidity, SUM _N is the integrated value, A is a constant, FANi is the detection value by the air flow rate detecting means at the i-th time, CMPi. Is the detection value by the capacity detection means at the i-th time, ti is the detection value by the outside air temperature detection means at the i-th time, RHi is the detection value by the outside air humidity detection means at the i-th time, and f (ti, RHi) is the outside temperature and the outside air humidity. When t = ti and RH = RHi in the function f (t, RH), The defrosting control device for a heat pump type air conditioner according to claim 1, which is obtained from a formula. 3. A variable capacity compressor, an outdoor heat exchanger, a pressure reducer, and an indoor heat exchanger are sequentially connected in an annular shape by a pipe to form a refrigerant circuit, and a change in outside air temperature and a change in outside air humidity. Output means for outputting a predetermined value at a predetermined outside air temperature and outside air humidity by using a humidity sensitive element whose resistance value changes according to the output value, output detection means for detecting the value output by the output means, and the variable capacity Capacity detecting means for detecting the capacity of the die compressor, air blowing amount detecting means for detecting the air blowing amount of the indoor air blowing means provided in the vicinity of the indoor heat exchanger, and the value detected by these detecting means in a predetermined cycle. A heat pump type air conditioner comprising a calculation means for performing calculation by using the above and a defrosting means for defrosting the outdoor heat exchanger when the integrated value reaches a predetermined value. Defrosting control device for machine. 4. The integrated value from the start of integration to the Nth time is SU
When _MN is an integrated value, A is a constant, FANi is a detection value by the air flow rate detecting means at the i-th time, CMPi is a detection value by the capacity detecting means at the i-th time, and OTi is a detection value by the output detecting means at the i-th time, [Equation 2] The defrosting control device for a heat pump type air conditioner according to claim 3, which is obtained from a formula. 5. A heat exchanger temperature detecting means for detecting the temperature of the outdoor heat exchanger is provided, and when the value detected by the heat exchanger temperature detecting means is equal to or more than a predetermined value, the calculation result is not changed. The defrosting control device for a heat pump type air conditioner according to any one of claims 1 to 4, which is not added to the integrated value. 6. A heat exchanger detecting means for detecting the temperature of the outdoor heat exchanger, wherein when the value detected by the heat exchanger temperature detecting means is a value of a predetermined value or more continuously for a predetermined number of times or more,
The defrost control device for a heat pump type air conditioner according to any one of claims 1 to 4, wherein the integrated value up to that point is set to 0. 7. The defrosting control device for a heat pump type air conditioner according to claim 1, wherein the integrated value is set to 0 at the start of heating operation and at the end of defrosting operation. 8. The heat pump type air according to claim 1, wherein when the value detected by the capacity detecting means is equal to or more than a predetermined number of times and is continuously less than or equal to the predetermined value, the integrated value up to that time is set to 0. Defrost control device for a harmony machine. 9. The defrosting prohibition section for prohibiting the defrosting operation regardless of the integrated value for a predetermined time from the start of the heating operation and the end of the defrosting operation, according to claim 1. Defrost control device for heat pump type air conditioner.