JPS61250438A - Defrosting operation control device for air conditioner - Google Patents

Abstract

PURPOSE:To accurately determine the frosting condition so as to improve the operation efficiency by providing a heat exchanger temperature sensor, an ambient air temperature sensor, a humidity sensor, an absolute humidity operator means and a comparator means, and determining the frosting condition for defrosting operation based on the detection of a fact that the temperature as detected by the outside heat exchanger temperature sensor is sub-zero and the comparative result by the comparator means. CONSTITUTION:The absolute humidity is determined by performing a calculation from the saturated water vapor volume relative to the temperature measured by an outside air temperature sensor 9 and the relative humidity measured by an outside humidity sensor 8. The determination is made under the condition that the temperature measured by a heat exchanger temperature sensor 7 is sub-zero, and the absolute humidity is found larger than the saturated water vapor volume for afore-said temperature when they are compared. The amount of frosting from the start of frosting is determined by performing a calculation from the difference between the absolute humidity and the saturated water vapor volume relative to the temperature of the outside heat exchanger as well as the temperature of the outside heat exchanger, and when it is determined that the frosting exceeded the predetermined level, the defrosting signal is outputted. In this manner, the determination of starting the defrosting operation can appropriately be made under any condition.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an air-source heat pump type air conditioner in which a compressor, a four-way valve, an outdoor heat exchanger, a throttling device, and an indoor heat exchanger are connected in sequence. This relates to a defrosting operation control device for a machine.

[Prior art and problems to be solved by the invention] Conventionally,
In the refrigeration cycle of this type of air conditioner, as shown in Figure 6, during heating operation, the refrigerant discharged from compressor a passes through a four-way valve as shown by the solid arrow, and is condensed in indoor heat exchanger C. and passes through capillary tubes d and e to outdoor heat exchanger f
It evaporates, passes through the service valve again, and returns to compressor a.

In addition, when the outside temperature is low, the temperature of the outdoor heat exchanger f becomes low, and eventually frost begins to adhere to the surface of the outdoor heat exchanger f, which causes the heat transfer characteristics to deteriorate and the heat exchanger capacity to rapidly decrease. At first, the heating capacity also decreases.

Therefore, the pipe temperature of the outdoor heat exchanger f is detected by the heat exchanger temperature sensor g, and the outside air relative humidity is detected by the outside air humidity sensor h, and when the pipe temperature of the outdoor heat exchanger f is below a certain temperature, And when the relative humidity is above a certain value, as shown by the broken line in the figure, cooling operation is started, and high-temperature, high-pressure refrigerant is sent to the outdoor heat exchanger f to melt the frost attached to the outdoor heat exchanger f. , the capacity of the outdoor heat exchanger f is restored and the heating operation is resumed as indicated by the solid line in the figure.

However, in the conventional defrosting operation mode as mentioned above,
The criteria for starting the defrosting operation are only the temperature of the outdoor heat exchanger f and the relative humidity of the outside air, so depending on how the constant value for relative humidity is determined, the defrosting operation may not start even if frost has formed, or the defrosting operation may not start even if frost has formed. There was a drawback that the defrosting operation was performed even when no frost had formed.

In other words, relative humidity is the ratio of the amount of water vapor actually contained in a given volume of air to the maximum amount of water vapor that the air can contain at that temperature (saturated water vapor amount), expressed as a percentage. . When this is expressed as a temperature vs. water vapor amount characteristic, it is represented by a curve that lies between the horizontal axis and the 100% (saturated water vapor amount) characteristic curve X, as shown in FIG. No matter what the relative humidity is, unless the temperature of the outdoor heat exchanger f is below zero, frost will not form, and the temperature of the outdoor heat exchanger f is exposed to the outside air and is not relative to the outside temperature. Thus, a substantially constant temperature difference ΔT is exhibited.

Therefore, if the outside air temperature when the temperature of the outdoor heat exchanger f is 0 degrees is T1, and the saturated water vapor amount when the temperature is 0 degrees is DI, then T
Frost will form at a relative humidity within the range surrounded by the straight line Yl passing through DI parallel to the vertical axis, the straight line Zl passing through DI parallel to the horizontal axis, and the above-mentioned curve X. The minimum relative humidity RH1 at which frost formation occurs is on the curve Xl, and this relative humidity RH1 is determined as the above-mentioned constant value. Furthermore, if the outside air temperature drops to T2 as shown in the figure, and the temperature of the outdoor exchanger f also drops to T3, then T2
Frost formation occurs at the relative humidity surrounded by the straight line Y2 parallel to the vertical axis passing through, the straight line Z2 passing through the saturated water evaporation amount D2 at temperature T3, and the curve X, but the relative humidity RH1 set above is Y2, Z2, Since it is not within the range surrounded by X, the relative humidity detected by the humidity sensor is RH+
When this happens, it is assumed that frost has formed and the defrosting operation is performed even if there is actually no frost.

This phenomenon is more noticeable in a refrigeration cycle in which a variable capacity inverter type compressor is used and ΔT is varied.

Therefore, in such cases, no matter how much defrosting operation is performed,
The heating capacity cannot be improved, and conversely, during defrosting operation, heating operation is stopped, resulting in a drop in room temperature, which impairs comfort. This had the disadvantage that the equipment would rotate backwards, reducing operating efficiency.

In order to overcome the above drawbacks, the amount of moisture in the air flowing into the outdoor heat exchanger and the amount of moisture in the air flowing out can be obtained by using a humidity sensor and a temperature sensor installed at the inlet and outlet, respectively. An apparatus has been proposed in which the amount of frost is determined by calculation based on the signals and the difference between them, but this apparatus requires a large number of sensors, has a complicated structure, and is expensive.

Means for Solving Problems c] The present invention eliminates the above-mentioned drawbacks of the conventional ones, appropriately determines frost formation, improves operating efficiency, and provides an air conditioner with a simple and inexpensive configuration. It is an object of the present invention to provide a frost operation control device, and the device according to the present invention has been made to achieve the object. sensor and
a humidity sensor that detects the humidity of the outside air, and an absolute humidity calculation means that calculates the absolute humidity of the outside air based on the temperature detected by the outside air temperature sensor and the humidity detected by the humidity sensor;
a comparison means for comparing the saturated water vapor amount with respect to the temperature detected by the exchanger temperature sensor and the calculated absolute humidity, and a comparison by the comparison means that the temperature detected by the outside air exchanger temperature sensor is below zero degrees; The present invention is characterized in that frost formation is determined based on the effect and the defrosting operation is controlled based on the determination.

A further object of the present invention is to provide a defrosting operation control device for an air conditioner that can appropriately start a defrosting operation after determining whether frost has formed. The apparatus according to the present invention has a means for calculating a condensed moisture amount which is the difference between the calculated absolute humidity and a saturated water vapor amount when frost formation is determined by the determination means; A means for calculating the time period during which the amount of frost formation is at a predetermined amount based on the temperature detected by the exchanger temperature sensor and the amount of condensed moisture is provided, and the defrosting operation is started when the calculated time has elapsed after the frost formation determination. It is characterized by

[For production]

Calculate the absolute humidity from the outside air temperature and the relative humidity at that temperature, and provide that the absolute humidity is at least the saturated amount of water vapor for the temperature of the outdoor heat exchanger, and the temperature of the outdoor heat exchanger is below zero degrees. Since the defrosting operation is controlled by determining the start of frost formation, it is possible to improve operational efficiency and to appropriately determine the start of frost formation even if the capacity of the outdoor heat exchanger changes.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 5.

First, conditions for frost formation on the outdoor heat exchanger will be explained.

Frost formation occurs when the temperature of the outdoor heat exchanger is below zero degrees and there is condensed water on the surface of the outdoor heat exchanger. In addition, condensed water on the surface of the outdoor heat exchanger is generated when the amount of water vapor contained in the outside air sent to the surface of the outdoor heat exchanger by the fan is greater than or equal to the saturated amount of water vapor at the temperature of the outdoor heat exchanger. .

From the above, by knowing the temperature and relative humidity of the outside air and the temperature of the outdoor heat exchanger, the frosting conditions can be determined as follows.

Since the saturated water vapor amount Ds for each temperature is known as shown in Figure 3, in the same figure, the water vapor amount in the outside air, that is, the absolute humidity D, can be calculated from the relative humidity RH and the outside air temperature TA as D SA -RH/100 By comparing the absolute humidity D^ and the saturated water vapor amount Dsε at the temperature TE of the outdoor heat exchanger,
By detecting TE<OdegaD^>Dsε, it is possible to detect the conditions under which frost formation begins. Of course, no frosting occurs when Tε>0 or when DA<DSε.

Generally, it is known that the performance of an outdoor heat exchanger does not decrease just when frost begins to form, but only when a certain amount of frost is exceeded. Therefore, it is completely wasteful to start the defrosting operation immediately upon detection of the frosting condition, and it is preferable not to start the defrosting operation until the amount of frosting reaches the predetermined value V.

By the way, the frost formation rate when the above-mentioned frost formation conditions are satisfied is the condensed moisture amount ΔD (=D^
-Dsε), and inversely proportional to the temperature Tε (kuo) of the outdoor heat exchanger, as shown in FIG.

Therefore, when the sum of the condensed water content ΔD and the outdoor heat exchange temperature Tε, which have constant constants α and β, respectively, integrated over time t, becomes larger than the predetermined value ■, that is, fαΔDdt+ fβTεdt>V. When this happens, it is assumed that a predetermined amount of frost has been present on the material, and a defrost signal is generated to start the defrosting operation. Now, assuming that there is no change in ΔD and Tε after the start of frost formation, t can be determined as follows.

Solving the above equation for t yields: ■ αΔD+βTε. Therefore, the actual generation of the defrost signal can be simply performed when the timer is started and the time t is counted upon detection of the frosting condition.

Next, a defrosting operation control device according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2.

In the figure, 1 is a compressor, 2 is a four-way valve, 3 is an indoor heat exchanger, 4 and 5 are capillary tubes, and 6 is an outdoor heat exchanger. By sequentially connecting these, a well-known refrigeration cycle is constructed. are doing. The refrigerant flows as shown by the solid line during heating, and flows as shown by the broken line during defrosting and cooling operations. 7 is an exchanger temperature sensor of the outdoor heat exchanger 6, 8 is an outside air humidity sensor, and 9 is an outside air temperature sensor.

The start of frosting is determined by calculating the absolute humidity based on the saturated water vapor amount for the temperature measured by the outside air temperature sensor 9 and the relative humidity measured by the outside air humidity sensor 8, and when the temperature measured by the exchanger temperature sensor 7 is below zero degrees. , and by comparing the saturated water vapor amount at the temperature with the above-mentioned absolute humidity, this is determined on the condition that the absolute humidity is large. The generation of the defrost signal is determined by calculating the amount of frost formed from the start of frost formation using the difference between the absolute humidity and the saturated water vapor amount with respect to the temperature of the outdoor heat exchanger, and the temperature of the outdoor heat exchanger. This is done in response to the amount of frost reaching a predetermined value or higher.

Next, the control circuit of the same embodiment will be explained with reference to FIG.

In the figure, the control circuit 10 includes an exchanger temperature sensor 7.
, an outside air humidity sensor 8, and an outside air temperature sensor 9 are connected. The control circuit 1O has sense amplifiers 10a, 1Ob, and 10c that amplify detection signals from each sensor.The output of the sense amplifier 10a is input to one input of the absolute humidity calculation circuit 10d, and the output of the sense amplifier 10b is connected to the above-mentioned absolute humidity. The output of the sense amplifier 10c is connected to the other input of the arithmetic circuit lOd, the input of the below-zero temperature detection circuit 10e, and the input of the saturated water vapor amount determination circuit 10f, respectively.

The below-zero temperature detection circuit 10e detects that the exchanger temperature TE applied to its input is below zero degrees, outputs a detection signal to its output, and sends this to the absolute humidity calculation circuit 10d.
, is applied to the control human power C of the saturated water vapor amount determining circuit 10f and one input of the AND circuit 10g.

When a signal is applied to the control human power C, the absolute humidity calculation circuit 10d receives the outside air temperature T applied to its input.
From A, the outside air relative humidity RH, and the saturated water vapor amount DSA for the known outside air temperature, the absolute humidity Do of the outside air is calculated using the following formula %.

The saturated water vapor amount determination circuit 10f determines the saturated water vapor amount DSE for the exchanger temperature Tε applied to its input.

The output of the absolute humidity calculation circuit 10d and the output of the saturated water vapor amount determination circuit 10f are the same as that of the comparison circuit 10h and the difference calculation circuit 10.
It is connected to both of i and the comparison circuit 10h.
, a comparison is made between the absolute humidity and the saturated water vapor 11Dsε, and when D^>DSH, a signal is outputted and applied to the other input of the AND circuit 10g. When a signal is applied to its re-entrance, the AND circuit 10g outputs a signal to its output, which is sent to the timer circuit 10j.
is applied to the starting human power T and the control human power C of the difference calculation circuit lO1.

When a signal is applied to the control human power C, the difference calculation circuit 10i calculates the difference between the absolute humidity DA applied to its input and the saturated water vapor amount Dsε, that is, the condensed water vapor amount ΔD, using the following formula: The calculation result is applied to one input of the time calculation circuit 10. The exchanger temperature TE is applied to the other input of the time calculation circuit 10, and the calculation expressed by the following formula is performed here to determine the time t.

t=V/(αΔD+βTε) In the formula, ■ is a predetermined constant value, which corresponds to the amount of frost on the outdoor heat exchanger that reduces the efficiency of the outdoor heat exchanger, and α,
β is a constant.

The time t obtained by the time calculation circuit 10k is compared with the time measured after activation of the timer circuit 10j in the comparison circuit 102, and when the measured time becomes greater than t, a signal is outputted to the output of the comparison circuit 101. This signal is used as a defrost signal to turn on a relay coil (not shown), switch the four-way valve, and set the defrosting operation mode.

〔Effect of the invention〕

As explained above, according to the present invention, the start of frost formation can be appropriately determined under any conditions. Moreover, in the preferred embodiment, the time point at which the defrosting operation starts can be determined so as to make maximum use of the outdoor heat exchanger capacity, thereby further improving the operating efficiency. These are realized by processing signals from three sensors, and advantages such as a relatively simple configuration can be obtained.

[Brief explanation of drawings]

FIG. 1 is a refrigeration cycle diagram of an air conditioner equipped with a defrosting operation control device according to an embodiment of the present invention, FIG. 2 is a block diagram showing an electric circuit of the defrosting operation control device, and FIGS. FIG. 5 is a graph for explaining the present invention in detail, FIG. 6 is a refrigeration cycle diagram showing a conventional example, and FIG. 7 is a graph for explaining the drawbacks of the conventional example. 1... Compressor, 2... Four-way valve, 3... Indoor heat exchanger, 4.5... Capillary tube, 6... Outdoor heat exchanger, 7... Exchanger temperature sensor, 8...Outside air humidity sensor, 9...Outside air temperature sensor, 10...Control circuit, 10d...Absolute humidity calculation circuit, 10e...Zero temperature or below detection circuit, 10f...Saturated water vapor amount determination circuit , Lo
g...AND circuit, 10h...comparison circuit, 10i.
...Difference calculation circuit, 10j...Timer, 10k...
Time calculation circuit, 10f... comparison circuit. Patent Applicant Saginomiya Seisakusho Co., Ltd. Figure 1 Algae T'Cl;1iJiA('?l AD Yasushi 71
TE ('C) Figure 6 73 0T2 Tl Onfi ('C) Procedural amendment (spontaneous) October 31, 1985 Mr. Uga Michibu of the Demand Agency 1, Indication of the case Patent application No. 087535 of 1985
No. 2, Name of the invention: Air conditioner defrosting operation control device 3, Person making the amendment: Patent applicant address: 2-55 Wakamiya, Nakano-ku, Tokyo, No. 5 Name: Ii-sho Co., Ltd. 4, Agent 5, Date of amendment order: Month, Day 6, 1939. Contents of amendment to increase the number of inventions due to amendment (Japanese Patent Application No. 60-087535) 1. The scope of claims in the specification is amended as follows. (l) In an air conditioner consisting of a compressor, a four-way valve, an outdoor heat exchanger, a throttling device, and an indoor heat exchanger in sequence, an exchanger temperature sensor that detects the temperature of the outdoor heat exchanger, and an exchanger temperature sensor that detects the temperature of the outdoor heat exchanger; an outside air temperature sensor that detects the temperature of the outside air; a humidity sensor that detects the humidity of the outside air; an absolute humidity calculation means that calculates the absolute humidity of the outside air based on the temperature detected by the outside air temperature sensor and the humidity detected by the humidity sensor; Comparing means for comparing the saturated water vapor amount with respect to the temperature detected by the exchanger temperature sensor and the calculated absolute humidity, and the temperature detected by the exchanger temperature sensor is below zero degrees and the comparative effect of the comparing means. A defrosting operation control device that determines frost formation and controls defrosting operation based on the determination. (2) A compressor, a four-way valve, an outdoor heat exchanger, a throttle device, and an indoor heat exchanger are sequentially operated. In the air conditioner formed by the birth canal, an exchanger temperature sensor that detects the temperature of the outdoor heat exchanger;
an outside air temperature sensor that detects the temperature of the outside air; a humidity sensor that detects the humidity of the outside air; and an absolute humidity calculation means that calculates the absolute humidity of the outside air based on the temperature detected by the outside air temperature sensor and the humidity detected by the humidity sensor; Comparison means for comparing the saturated water vapor amount with respect to the temperature detected by the exchanger temperature sensor and the calculated absolute humidity, the temperature detected by the exchanger temperature sensor being below zero degrees, and the comparison effect of the comparison means. a determining means for determining frost; a means for calculating a condensed moisture content which is the difference between the calculated absolute humidity and a saturated water vapor amount when determining frost formation by the determining means; and the replacement when determining frost formation by the determining means. means for calculating the time required for the amount of frost to reach a predetermined amount based on the temperature detected by the temperature sensor and the amount of condensed moisture, and the defrosting operation is started when the calculated time has elapsed after determining the formation of frost. A defrosting operation control device characterized by: ” 2. In the same book, page 3, line 13, “valve used” is corrected to “four-way valve.” 3. In the same book, page 5, line 16, “tomo” is changed to “to”
Correct. 46 "D3" on page 9, line 14 of the same book is corrected to rDsaJ. 5. Correct rTEJ to "T," on page 9, line 19 of the same book. 6. Insert "abbreviation" before "proportionality" in line 13 of page 10 of the same book. 7. In the same book, page 10, line 14, before "outdoor heat exchanger"
, ΔT (-TA Tx ) is constant, insert ". 8. In the same book, page 10, line 15, "inversely proportional" is corrected to "approximately proportional." 9. Figures 1, 2, 5, 6 and 7 are replaced with the attached drawings. Patent applicant Susumiya Seisakusho Co., Ltd. V 1 return TE ('C) Figure 6 Ts OT2 Tl 1a cliff (@C)

Claims (2)

[Claims] (1) In an air conditioner in which a compressor, a four-way valve, an outdoor heat exchanger, a throttle device, and an indoor heat exchanger are connected in sequence, an exchanger temperature sensor that detects the temperature of the outdoor heat exchanger and the temperature of the outside air are provided. an outside air temperature sensor that detects the humidity of the outside air, a humidity sensor that detects the humidity of the outside air, an absolute humidity calculation means that calculates the absolute humidity of the outside air based on the temperature detected by the outside air temperature sensor and the humidity detected by the humidity sensor, and the exchanger. Comparing means for comparing the saturated water vapor amount with respect to the temperature detected by the temperature sensor and the calculated absolute humidity; Determine frost,
A defrosting operation control device that controls defrosting operation based on the determination. (2) In an air conditioner that sequentially communicates a compressor, a four-way valve, an outdoor heat exchanger, a throttling device, and an indoor heat exchanger, an exchanger temperature sensor that detects the temperature of the outdoor heat exchanger and the temperature of the outside air are provided. an outside air temperature sensor that detects the humidity of the outside air, a humidity sensor that detects the humidity of the outside air, an absolute humidity calculation means that calculates the absolute humidity of the outside air based on the temperature detected by the outside air temperature sensor and the humidity detected by the humidity sensor, and the exchanger. Frost formation is determined based on a comparison means for comparing the saturated water vapor amount with respect to the temperature detected by the temperature sensor and the calculated absolute humidity, the temperature detected by the exchanger temperature sensor being below zero degrees, and the comparison effect by the comparison means. a means for calculating a condensed moisture amount which is the difference between the calculated absolute humidity and a saturated water vapor amount when frost formation is determined by the determination means; and the exchanger temperature sensor when frost formation is determined by the determination means. Based on the temperature detected by and the amount of condensed water,
What is claimed is: 1. A defrosting operation control device comprising means for calculating a time period for which the amount of frost formation reaches a predetermined amount, and starting a defrosting operation when the calculated time period has elapsed after frost formation determination.