JPS6146829A - Defrosting control device in air conditioning machine - Google Patents

Abstract

PURPOSE:To perform a rational defrosting operation in a defrosting control device for a heat pump type air conditioning machine having a micro-computer by a method wherein a defrosting operation temperature is varied in response to a high or low outdoor temperature and a four-way valve is controlled in response to a result of comparison between the operating temperature and a temperature of outdoor heat exchanger. CONSTITUTION:An outdoor temperature is sensed at I, compared with a predetermined temperature, a signal is outputted to a defrosting operating temperature transferring means, a defrosting operating temperature is varied in sequence and then is inputted to a comparator means II. Outdoor heat exchanger temperature IIis inputted to the comparator means II and then compared with the defrosting operation temperature. At this time, at the comparisons I and II, timing is controlled with a time measuring means. Prestored output mode is outputted in response to the comparison result II, a four-way valve is controlled and the defrosting operation is performed. With this arrangement it is possible to reduce the number of operations of defrosting, increase a mean heating capability and also decrease the feeling of cooling air in view of its operating time.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a defrosting control device for a heat pump type air conditioner, the operation control device of which is equipped with a microcomputer.

The structure and problems of the conventional example The structure and problems of the conventional example will be explained with reference to FIGS. 4 and 5. FIG. 4 is a refrigeration cycle diagram of a heat pump air conditioner, including a compressor 101, a four-way valve 102, an indoor heat exchanger 103, an indoor blower 104, and a pressure reducing device 10.
5. It is formed by an outdoor heat exchanger 106, an outdoor blower 107, and the like.

During heating, the air is sucked into the compressor 101 as shown by the solid arrow in the figure. Here, when the outside temperature is low, the temperature of the outdoor heat exchanger 106 decreases and frost formation on the heat exchanger progresses, making it difficult to absorb heat from the outdoor heat exchanger 106 and reducing the heating capacity. do.

Conventionally, this state of frost is detected by a temperature sensor installed in the outdoor heat exchanger 106, and when the detected temperature falls below a certain set temperature, defrosting operation (cooling operation is performed by switching the four-way valve) and the outdoor heat is removed. However, if the outside temperature is particularly low, the evaporation pressure itself will be low, so even if there is no frost on the heat exchanger, the detected temperature will be low, so it may be removed. It had the disadvantage of entering into frost operation.

FIG. 5 shows the change in heating capacity when the outside temperature is 15°C. The vertical axis shows heating capacity, and the horizontal axis shows time. Because the outside temperature is low, the outdoor heat exchanger temperature is always below the defrosting set temperature, and defrosting is performed once every hour (in this example, The interval between frost operations is at least 1 hour, and if the heating operation is over 1 hour and the heat exchanger temperature is below the set temperature, the defrost operation is activated.) As is clear from the figure, no decrease in heating capacity was observed before defrosting (no frost formation on the toes), indicating that this defrosting was originally unnecessary.

Therefore, the heating capacity per unit time decreases by the amount of the defrosting time, and the defrosting feeling deteriorates.

OBJECTS OF THE INVENTION It is an object of the present invention to eliminate the above-mentioned conventional drawbacks and realize more rational defrosting control.

Structure of the Invention To achieve this object, the present invention, as shown in FIG. Comparison means for comparing electrical signals and outputting control signals;
A comparison of electrical signals from a transition means for sequentially shifting the defrosting operating temperature according to the control signal and a temperature detecting means II for detecting the defrosting operating temperature determined by the shifting means and the temperature of the outdoor heat exchanger. means II, a timing means for giving comparison timing to the comparison means I and the comparison means (2), a storage means for outputting an output mode determined by the electric signal from the comparison means II, and a signal from the storage means, It is equipped with an output means for controlling a four-way valve and the like to perform defrosting operation.

With this configuration, in the case of heating operation, it becomes possible to appropriately select the defrosting operation temperature according to the outside temperature, and rational defrosting control becomes possible.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 2 and 3. Here, since the refrigeration cycle is the same as the conventional example, illustration and description thereof will be omitted, and the control contents regarding defrosting will be explained.

FIG. 2 is a defrosting electronic control circuit diagram, in which 1 is an outside temperature thermistor that detects the outdoor temperature, 2 is an outside temperature detection device that converts the detected temperature a into an electrical signal and outputs it, and 3
is a piping thermistor that detects the temperature of the outdoor heat exchanger, 4
a comparator 5 that detects the temperature detected by the piping thermistor 3 and compares it with the temperature level of the defrosting operation temperature T, ~T2;
is the above T.

A reference voltage generating section that determines a voltage level according to the defrosting operation temperature of ~T2 generates a constant voltage corresponding to each temperature of T and ~T2. Reference numeral 6 denotes a microcomputer (hereinafter referred to as LSI) which is internally equipped with a comparison function, a timer function, a transition function, a function for storing various output modes, and the like. Reference numeral 7 denotes a defrosting signal output section of the LSI 6, which is composed of a switching transistor 7a, a relay coil zlz7b, and a relay contact 7c. Said relay carp 1V7c
controls energization to an electromagnetic coil /L/ (not shown) that drives a four-way valve and the like.

To explain the relationship between the block diagram shown in Fig. 1 and the defrosting electronic control circuit diagram shown in Fig. 2, external means ■ and ■
, a moving means, a storage means, and the defrosting signal output section 7 correspond to an output means, respectively.

Next, in the above configuration, the defrosting control is set to the 30th setting. Next, the outside temperature thermistor 1 is measured and compared with the set temperature S, and based on this result, the defrosting operation temperature T
(T, <T2) is determined, and if the outside temperature a is lower than the set temperature, the defrosting operation temperature is determined to be the lower T.
The voltage is output from the board to the reference voltage generator 5.

Generally, defrost control is provided with a minimum defrost interval in order to prevent frequent defrosting operations. This is the defrosting interval judgment in the figure, and the timer repeats counting until it exceeds N. When it reaches nnN, the temperature detected from the piping thermistor 3 is the voltage level corresponding to T1 or T2 of the reference voltage generator 5. A comparison is made with
ONL defrosting operation is started for the 1 Bohr output section. If the detected temperature is b) T, the heating operation is continued and the timer count advances. When defrosting progresses and the detected temperature reaches the defrosting end temperature U, defrosting ends and normal heating operation returns.

JP-A-Sho Gl-4G829 (3) By configuring the above modes, it becomes possible to select the optimal defrosting operation temperature according to the outside temperature. By lowering the operating temperature, the number of times defrosting is reduced, the average heating capacity is increased, and the feeling of deterioration during defrosting can be reduced in terms of number of times.

Figure 6 shows the change in heating capacity when the defrosting operation temperature is lowered based on the above example.
This figure is for the case where the outside temperature is -5°C, which is the same as in Fig.
It is set to °C.

In the conventional example, defrosting is performed at the minimum defrosting interval of once every hour even though there is no decrease in heating capacity, whereas in this example, defrosting is performed once every two hours. The number of frosts has been halved, allowing for more rational defrost control depending on the outside temperature.

In addition, in the above embodiment, only one set temperature is used for outside temperature determination, but multiple set temperatures can be used for defrosting.
A similar effect can be obtained by increasing the number of operating temperatures.

Effects of the Invention As is clear from the above embodiments, the defrosting control of the air conditioner according to the present invention reduces the number of defrosting operations that are not originally required by appropriately selecting the defrosting operation temperature according to the outside temperature. It has excellent effects such as increasing the average heating capacity and reducing the number of times the cold air feels during defrosting.

[Brief explanation of the drawing]

FIG. 1 is a block diagram expressing the defrosting control of the present invention using a function realizing means, and FIGS. 2 and 3 are a defrosting electronic control circuit diagram and a flowchart showing the defrosting control, respectively, showing one embodiment of the present invention. , Fig. 4 is a diagram of a conventional heat pump refrigeration cycle, Fig. 5 is a heating capacity diagram of a conventional defrosting control device at low outside temperatures, and Fig. 6 is a diagram of an embodiment of the present invention at low outside temperatures. It is a heating capacity diagram. 1 Outside temperature thermistor, 3. Piping thermistor, 6
Microcomputer, 7... Defrost signal output section. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 3
Figure 4 Figure 5

Claims (1)

[Claims] A compressor, a four-way valve, an indoor heat exchanger, a pressure reducing device, an outdoor heat exchanger, etc. are connected in a ring to form a heat pump type refrigeration cycle, and a temperature detection means for detecting the outdoor temperature.
I, a comparison means I that compares an electric signal from the temperature detection means I with an electric signal of at least one set temperature and outputs a control signal, and a comparison means I that sequentially shifts a plurality of defrosting operating temperatures according to the control signal. a transition means, a comparison means II that compares an electrical signal from a temperature detection means II that detects the defrosting operation temperature determined by the transition means and the temperature of the outdoor heat exchanger, and a comparison means I and a comparison means II. a timing means for providing a comparison timing, a storage means for outputting an output mode determined by the electric signal from the comparison means II, and a defrosting operation by controlling the four-way valve etc. by the signal from the storage means. A defrosting control device for an air conditioner equipped with an output means.