JPS62119344A - Defrosting control device of air conditioner - Google Patents

Abstract

PURPOSE:To secure heating capacity for a given time and take out the limit of heating capacity by switching heating operation to defrosting operation in such a way that heating operation is carried out without detecting frost for a given time after the start of heating operation and the temp. of refrigerant gas in an overheated zone at the inlet piping of an indoor side heat exchanger is detected. CONSTITUTION:After the temporary operation stop of a compressor in refrigerating cycle, the operation time from re-starting is counted and heating operation is continued for the set time. Thereafter, when refrigerant temp. detected by a temp. detecting element 6 placed at the refrigerant inlet side of an indoor side heat exchanger 3 is lower than the set temp., a signal switching a heating cycle to a defrosting cycle is emitted from a judging means to effect defrosting operation. Thereby, heating operation is secured for a given time and such a case as defrosting operation is carried out in spite of no frosting is prevented. Heating capacity near its limit is able to be taken out by simple constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a control device for a separate heat pump type air conditioner, and particularly to a control device for detecting frost on an outdoor heat exchanger indoors. Regarding air conditioners.

2. Description of the Related Art Conventionally, as shown in Japanese Patent Publication No. 59-34255, the H,65 condition of the outdoor heat exchanger is detected based on both the temperature change of the indoor heat exchanger and the indoor temperature change. , technology has been developed to control heating and defrosting operations.

Problems to be Solved by the Invention However, such a conventional configuration requires a plurality of temperature detection elements, complicating the circuit itself. Furthermore, in air conditioners, the air flow inside the room is usually variably set arbitrarily, and for this reason, adding an air volume correction means to the conventional technology would further complicate the circuit. .

Moreover, since this configuration detects the temperature of the gas-liquid mixed refrigerant while it is flowing through the heat exchanger, the temperature change between arrival and non-arrival is small, making it possible to determine arrival 1 within a minute range. Therefore, there is a problem that the detection process is not stable.

In addition, in recent years, control devices are often configured by using microcomputers to perform complicated signal processing, but the fact that there are many input signal sources (temperature detection elements) as in the conventional technology makes it difficult to create the program. It is also a popular book, and there are limits to the simplification of the program.

As described above, the conventional technology has many problems, and improvements are required.

The present invention addresses the drawbacks of the conventional art and provides a defrosting control device that can be simplified in configuration without the disadvantages of the prior art.

Means for Solving the Problems In order to solve the above problems, the present invention, as shown in FIG. a time measuring means for measuring the time from the start of restart; a set time storage means for storing a preset time;
a first comparing means for detecting and outputting a match between the time detected by the time measuring means and the time set in the set time storage means; and a temperature of a pipe connected to the refrigerant inlet side of the indoor heat exchanger. temperature detection means for detecting a temperature, set temperature storage means for storing a boundary value temperature for switching a heating cycle to a defrosting cycle, and a set temperature storage means for storing a boundary value temperature at which the temperature detected by the temperature detection means is higher than the boundary value temperature stored in the set temperature storage means; A second comparing means detects and outputs a decrease in temperature, and a set time elapsed signal from the first comparing means and a boundary value drop signal from the second comparing means are used to switch from the heating cycle to the defrosting cycle. The apparatus is comprised of a determining means for making a determination, and a selection output means for controlling the refrigeration cycle from heating operation to defrosting operation in accordance with the output of the determining means.

Effect: With this configuration, the heating operation is ensured until a predetermined time has elapsed from the start of the heating operation, and after the elapse of the predetermined time, the defrosting operation is controlled based on the temperature detected by the temperature detection means.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to FIGS. 2 to 5.

FIG. 2 is a refrigeration cycle diagram showing one embodiment of the present invention.

In the figure, the refrigeration cycle includes a compressor 1 and a four-way switching valve 2.
, an indoor heat exchanger 3, a pressure reducer 4, and an outdoor heat exchanger 5 are connected in sequence. Reference numeral 6 denotes a pipe temperature detection element, which is attached to a pipe that is on the refrigerant inlet side of the indoor heat exchanger 3 (condenser) during heating. In this case, during cooling operation, the refrigerant flows in the direction of the solid line arrow in the figure, and during heating operation, the four-way switching valve 2 is switched so that the refrigerant flows in the direction of the broken line arrow in the figure.

Furthermore, the compressor 1, the four-way switching valve 2, the pressure reducer 4, the outdoor heat exchanger 5, and the outdoor blower 8 constitute an outdoor unit A. In addition, an operation control unit (not shown) includes a microcomputer (hereinafter referred to as microcomputer) programmed with the indoor heat exchanger 3 and the indoor blower 7, as well as a pipe temperature detection element 6, a timer function, a temperature control function, etc. ) is provided in indoor unit B. Here, the pipe temperature detection element 6 is attached at a location away from the wind circuit where it is not affected by the air blowing from the indoor blower 7. Alternatively, the location may be near the indoor unit B.

FIG. 3 is a main circuit diagram of the operation control section.

In the figure, the microcomputer 9 includes a storage section 10 that stores a time-safe circuit for determining operating time;
The drive signal generation means 11 generates an appropriate output signal from an AND circuit between the time safe circuit stored in the input value and the input value. Comparator 1 is on the input side of this microcomputer 9.
2, a pipe temperature detection element 6 (for example, a pipe thermistor or thermocouple element, etc.) serving as a temperature detection means and a temperature setting resistor 1a, 14, 1 whose resistance value can be changed as necessary.
5 is connected. Further, on the output side, a relay R1 that drives a four-way switching valve coil that is a driving means via switching transistors TR1 to TR4, a relay R2 that drives an indoor blower 7, a relay R3 that drives an outdoor blower 8,
A relay R4 that drives the compressor 1 is connected.

Here, comparing the configuration in FIG. 3 with the configuration in FIG. 1, the pipe temperature detection element 6 and the resistor 13 correspond to the temperature detection means in FIG. 1, and the comparator 12 corresponds to the second comparison means in FIG. The signal generated by the resistor 14.1S corresponds to the signal of the set temperature storage means shown in FIG. The drive signal generating means 11 corresponds to the determining means and the selection output means.

Next, the operation from the start of heating operation to defrosting operation will be explained.

The discharge refrigerant temperature of the compressor 1 is Td, the suction refrigerant temperature of the compressor 1 is T+s, and the discharge pressure of the compressor 1 is Pd.

When the suction pressure of the compressor 1 is Ps and the poIJ l-rope index is n (where 1<n<K, where K is the adiabatic compression index), the discharge refrigerant temperature Td is expressed by the following formula. The heat loss input refrigerant temperature Ts is high, and the discharge refrigerant temperature Td is also high. As the outside air cools and the snow builds up, the suction refrigerant temperature Ta decreases, and the discharge refrigerant temperature Td also decreases. The pipe temperature detection element 6 in the present invention is installed in the inlet pipe of the indoor heat exchanger 3, and detects the temperature of the part through which the high-temperature, high-pressure superheated refrigerant gas discharged from the compressor 1 flows. is a temperature lower than that of the discharged gas by a predetermined temperature due to heat loss in internal and external reading piping, etc.

Therefore, as shown in FIG. 4, when the outdoor heat exchanger 5 has not arrived at 5M, both the suction refrigerant temperature T3 of the compressor 1 and the inlet pipe temperature t of the indoor heat exchanger 3 are high; The temperature t gradually decreases, and when snow accretion occurs which significantly reduces the heating capacity, the temperature t of the inlet pipe of the indoor heat exchanger 3 extremely decreases. That is, if the inlet pipe temperature t becomes lower than the set pipe temperature t1, the heating capacity decreases, and since snow accumulation is progressing, it is necessary to remove the eyebrows.

In this way, since the inlet pipe temperature t of the indoor heat exchanger 3 is the temperature of the refrigerant gas in the superheated region, it is affected by the air volume of the indoor blower 7. The defrosting operation can be determined accurately based on the temperature of the inlet pipe of the indoor heat exchanger a.

Based on the above explanation, the control circuit shown in FIG.
Controls the contents of the flowchart shown in the figure.

That is, when the heating operation is started as shown in step 1 of FIG. 5, a timer count for a predetermined time T is set by the microcomputer 9 (step 2).

This timer count set is T1 from the start of heating operation.
This is to ensure heating operation for a period of time (for example, one hour), and one means is to forcibly continue heating for T1 hours, for example.

And once the timer count is set, step 3
It is determined that the T1 time has passed. The heating operation is continued until the time T1 has elapsed.

Then, when the time T1 has elapsed, the process moves to step 4, where a second timer counter is set, and the process moves to step 5, where it is determined in the microcomputer 9 whether or not the compressor 1 is operating. If no operation is being performed (if step 5 is not satisfied), the process returns to step 4 and the first timer counter is reset.

Next, when the conditions of step 5 are satisfied, 1 is set in step 6.
It is determined that two hours (for example, four minutes) have passed.

When the compressor 1 has been operated continuously for 12 hours, the process moves to step 7, where the pipe temperature t is read by the pipe temperature detection element 6, and the process moves to step 8 to check whether the compressor 1 is operating again. A determination is made whether or not.

Then, the process moves to step 9 and the pipe temperature t is set as the set pipe temperature t.
It is determined whether it is lower than 1. Specifically, the comparator 12 in FIG. 3 makes the determination.

When the conditions of step 9 are satisfied, the process moves to step 1o, and defrosting operation is started. That is, the transistors TR1, T'R2, TR3, and TR4 in FIG. 3 operate respectively to switch the four-way selector valve 2, and if necessary, before that, the compressor 1 is stopped for a certain period of time, and the indoor blower 7 and the outdoor blower are switched on. Stop 8. Defrost is then performed in the cooling cycle. Since the content of this defrosting operation is conventionally well known, detailed explanation will be omitted.

Further, the restoration of the heating operation can be carried out by any suitable means as is well known in the art.

In this embodiment, the defrosting operation is performed by switching from the heating cycle to the cooling cycle.
For example, it goes without saying that a configuration may be adopted in which the heating cycle is maintained and a separately stored refrigerant is flowed to the outdoor heat exchanger, or a configuration in which a separate heat source is used to melt the frost. Further, the compressor 1 may be operated continuously when switching to defrosting operation, and may be temporarily stopped before returning to heating operation.

Effects of the Invention As described above, according to the present invention, with the above-described configuration, the temperature of the refrigerant gas in the superheated region is detected at the indoor heat exchanger inlet piping, and the temperature is detected appropriately without being affected by the indoor wind 1. Reliable defrosting operation can be performed with a single temperature detection point, the configuration is very simple, and it can be determined whether the refrigerant has enough heat for heating by using the indoor heat exchanger. Since defrosting can be performed on the entrance side, it is possible to reliably determine whether there is actual heating capacity before defrosting.

In other words, in the present invention, there is no difference in the temperature of the refrigerant at which frost has completely formed between the inlet and the middle part of the heat exchanger, and when no frost has formed, the inlet refrigerant temperature is higher than the refrigerant temperature in the middle part. By focusing on a point that is extremely high and detecting the refrigerant temperature on the inlet side, it is possible to obtain large temperature changes from unfrosted to frosted, and it is possible to draw out heating capacity close to the limit by detecting the temperature at one point. . Furthermore, since the present invention does not detect frost formation until a certain period of time has elapsed from the start of heating, the heating capacity is ensured for that certain period of time, and comfort is not impaired.

In addition, after the compressor is temporarily stopped during heating operation, it is not detected until a certain period of time has elapsed since the restart of operation. It will not detect and mistakenly start defrosting operation even though no frost has formed.

[Brief explanation of drawings]

Fig. 1 is a block diagram expressing the defrosting control device of the present invention using function realizing means, Fig. 2 is a refrigeration cycle diagram of an air conditioner showing an embodiment of the present invention, and Fig. 3 is a block diagram of the defrosting control device of the present invention. A circuit diagram of the defrosting control device, Fig. 4 is a characteristic diagram showing the relationship between the temperature of the refrigerant flowing into the indoor heat exchanger and the compressor suction refrigerant temperature in the defrosting control device, and Fig. 5 is a diagram showing the relationship between the temperature of the refrigerant flowing into the indoor heat exchanger in the defrosting control device 3 is a flowchart showing the operation contents. 1... Compressor, 2... Four-way switching valve, 3...
... Indoor heat exchanger, 5 ... Outdoor heat exchanger, 6 ... Piping temperature detection element, 9 ... Microcomputer, 10 ...・Storage part, 11・
... Drive signal generation means, 12 ... Comparator, 13, 14, 15 ... Temperature setting resistor, A
...Outdoor unit, B...Indoor unit. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure/---L: g3? ---Sho Vn top and Ichito 18N trivial moxibustion S Figure 2 4-AIL & σ-i Gaiseretsu (Ryoki 6---Nyokan, 1 Kugike A--1 Sen, Yu 1- Eni, 71 B-m-in the house/to 10-first glance reward 11-11 cantering partner Uya) L+nuki/Z---Funno (shita/J,/4.) 5-1 Low 1tsuLノγ /1 Fig. 4 Ts--1pressure fall 4 & /l pL included 1! -#M Karikan 5th rI! J □ Stella 7°l □ Step 2 □ Amazing / 7' 3 □ Step 4 □ Step j □ Step t □ Step 7 □ Sugukugu δ □ Step 7 □ Sgoods π

Claims (1)

[Claims] A refrigeration cycle equipped with a compressor, an indoor heat exchanger, a pressure reducing device, and an outdoor heat exchanger is provided with cycle switching means for switching between a heating cycle and a defrosting cycle, and the cycle switching means is further configured to switch from a heating cycle to a defrosting cycle. A control device for switching the compressor to the compressor is controlled by a time measuring means for measuring the time from restarting the compressor after the compressor is temporarily stopped, a set time storage means for storing a preset time, and the time measuring means. a first comparison means for detecting and outputting a match between the detected time and the time set in the set time storage means; and a temperature detection means for detecting the temperature of a pipe connected to the refrigerant inlet side of the indoor heat exchanger. means, set temperature storage means that stores a boundary value temperature for switching a heating cycle to a defrosting cycle, and detects that the temperature detected by the temperature detection means has fallen below the boundary value temperature stored in the set temperature storage means. a second comparison means for outputting a second comparison means, and a determination means for determining switching from a heating cycle to a defrosting cycle based on a set time elapsed signal from the first comparison means and a boundary value drop signal from the second comparison means; A defrosting control device for an air conditioner, comprising a selection output means for controlling the refrigeration cycle from heating operation to defrosting operation according to the output of the determination means.