JPH04356649A - Air conditioner - Google Patents

Abstract

PURPOSE:To restrict or prevent occurrence of freezing sound in an outdoor heat exchanger during a heating operation. CONSTITUTION:When a heating operation with a freezing cycle is carried out, an operation of an outdoor fan 3 is controlled by a high pressure restricting and controlling device 12 in response to an on-off pattern set in advance in regard to a heating load when either an electrical energization current of a compressor 1 or a temperature of an indoor heat exchanger 7 exceeds a set value.

Description

[Detailed description of the invention]

[Object of the invention]

0002

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat pump type air conditioner, and more particularly to an air conditioner with improved high pressure suppression control means for suppressing overpressure in a refrigeration cycle when overcurrent in a compressor is detected.

0003

[Prior Art] Conventionally, this type of high-pressure suppression control device for air conditioners completely stops the operation of the outdoor fan for the required period of time when overcurrent in the compressor or overpressure in the refrigeration cycle is detected during heating operation. By doing so, the heat absorption effect by the outdoor heat exchanger is lowered to increase its evaporation temperature, and the pressure on the high pressure side is lowered.

0004

However, in such a conventional high-pressure suppression control device, the operation of the outdoor fan is completely stopped for a relatively long period of time from the start of the control operation until the return.

[0005] For this reason, the air blowing to the outdoor heat exchanger is almost stopped, which lowers the evaporation temperature of the outdoor heat exchanger and causes frost to grow, reducing the heat exchange efficiency and causing the fins to There is a problem in that freezing noise occurs due to freezing between the parts, and noise is generated.

[0006] The present invention was developed in consideration of the above circumstances, and its purpose is to stop the operation of the outdoor fan intermittently without completely stopping the operation when an overcurrent of the compressor is detected during heating operation. By operating the outdoor heat exchanger at a temperature of Our goal is to provide air conditioners. [Structure of the invention]

[0007]

[Means for Solving the Problems] In order to solve the above problems, the present invention is constructed as follows.

That is, the present invention provides a compressor, a four-way valve,
In an air conditioner that constitutes a refrigeration cycle by sequentially connecting an indoor heat exchanger equipped with an indoor fan, a pressure reducer, an outdoor heat exchanger equipped with an outdoor fan, etc. with refrigerant piping, during heating operation of the refrigeration cycle. , a high-pressure suppression control means for controlling the operation of the outdoor fan according to a preset on-off pattern according to the air conditioning load when the current flowing through the compressor or the temperature of the indoor heat exchanger exceeds a set value; It is characterized by having been established.

[0009]

[Function] During heating operation of the refrigeration cycle, if the compressor current or indoor heat exchanger temperature exceeds the set value, this is detected by the high pressure suppression control means and the outdoor fan is activated according to the air conditioning load. It operates intermittently according to a preset on/off pattern.

Therefore, according to the present invention, the outdoor fan is operated intermittently without being completely stopped while controlling the capacity according to the heating load, so that it is possible to follow the heating load, and the outside air is directed from the outdoor fan to the outdoor side. Air is blown to the heat exchanger intermittently.

[0011] For this reason, the evaporation temperature of the outdoor heat exchanger increases and the growth of frost is suppressed, so that the formation of ice between the fins is suppressed, and the freezing noise caused by the freezing is reduced or prevented. Can be done.

0012

Embodiments Hereinafter, embodiments of the present invention will be described based on FIGS. 1 to 5.

FIG. 2 is an overall configuration diagram of an embodiment of the present invention, which includes a compressor 1, a four-way valve 2, an outdoor heat exchanger 4 equipped with an outdoor fan 3, and an expansion valve which is a pressure reducer. 5
, an indoor heat exchanger 7 equipped with an indoor fan 6 is connected to a refrigerant pipe 8.
They are connected in this order in an annular manner to form a closed refrigeration cycle that reversibly circulates the refrigerant.

In this refrigeration cycle, when the refrigerant is circulated in the direction of the solid line arrow in the figure by switching the four-way valve 2, cooling operation is performed, and when the refrigerant is circulated in the direction of the broken line arrow in the figure, heating operation is performed. .

An indoor heat exchanger temperature sensor 7a detects the temperature of the indoor heat exchanger 7, a room temperature sensor 9 detects the room temperature, a room temperature setting device 10 sets the room temperature, and detects the current flowing through the compressor 1. A detection sensor 11 is electrically connected to a high pressure suppression control device 12.

The high-pressure suppression control device 12 is composed of, for example, a microcomputer, and detects, via the current sensor 11, an overcurrent in which the current flowing through the compressor 1 exceeds a set value, or when the temperature of the indoor heat exchanger 7 increases. When it is detected via the indoor heat exchanger temperature sensor 7a that the set value has been exceeded, the operation of the outdoor fan 3 is controlled on/off according to a preset on/off pattern depending on the size of the air conditioning load. Each pattern is stored in memory.

FIG. 1 shows an example of the control procedure of this high pressure suppression control device 12, and P1 to P8 in the figure indicate steps in the flowchart, respectively.

First, at P1, the high pressure suppression control device 12 detects the current I of the compressor 1 from the current sensor 11, the temperature Tc of the indoor heat exchanger 7 from the indoor heat exchanger temperature sensor 7a, and the temperature Tc of the indoor heat exchanger 7 from the room temperature setting device 10. The set temperature Ts of the room temperature and the room temperature Ta from the room temperature sensor 9 are read respectively.

Next, in P2, it is determined which of the zones A, B, and C shown in FIG. Proceed to P3, P4, and P5, respectively. In addition, in Figure 3,
The arrows indicate the increasing and decreasing directions of the current I flowing through the compressor 1.

When the energizing current I of the compressor 1 is in zone A, it is determined that there is not an overload but an overcurrent due to the occurrence of some kind of abnormality, and the process proceeds to P3, where the compressor switch 1a is turned off and the compressor is turned off. The operation of the compressor 1 is stopped, and the operation of the compressor 1 is maintained in the stopped state for, for example, 2 minutes and 20 seconds at P6, and then normal operation is resumed.

Further, when the current I flowing through the compressor 1 is in the B zone, it is determined that there is an overcurrent, and the process proceeds to P4.
Here, in order to judge the size of the heating load, the set temperature T
It is determined whether the difference between s and the room temperature Ta is greater than a predetermined value α, that is, whether Ts−Ta≧α holds true. If it holds true, it is determined that the heating load is large and the process proceeds to P7, where the The operation of the outdoor fan 3 is controlled on/off according to the on/off pattern indicated by 4 (large load). For example, an on-off pattern is repeated in which the outdoor fan 3 is stopped for 30 seconds t3 to stop blowing air to the indoor heat exchanger 4, and then is operated for 5 seconds t4.

Furthermore, if Ts-Ta≧α does not hold in P4, it is determined that the heating load is small and the process proceeds to P8, where the operation of the outdoor fan 3 is turned on and off according to the on-off pattern shown in (Low load) in FIG. Control. For example, the outdoor fan 3 is controlled to be turned on and off using an on-off pattern such as stopping operation for 30 seconds t1 and then operating it for 2 seconds t2.

[0023] Then, the current I of the compressor 1 is C
When it is in the zone, it is determined that the current I is normal and the process proceeds to P5, where the normal operation is further continued and the operation of the compressor 1 and the outdoor fan 3 is continued.

Therefore, according to this embodiment, when the current I of the compressor 1 or the indoor heat exchanger temperature Tc belongs to zones A and B shown in FIG. As shown in the conventional example shown in FIG. The evaporation temperature can be raised by blowing air to

[0025] Therefore, the growth of frost on the outdoor heat exchanger 4 is suppressed, so that icing can be suppressed and icing noise can be suppressed or prevented.

Furthermore, since the evaporation temperature of the outdoor heat exchanger 4 increases, the time until the start of the defrosting operation can be extended and the efficiency of the heating operation can be increased.

Furthermore, in the conventional control shown in FIG. 4, an overshoot o occurs in which the current range of the compressor 1 exceeds the set current I2, but in the control of this embodiment, the overshoot o hardly occurs.

In the above embodiment, the case where the operation of the outdoor fan 3 is controlled when the current I flowing through the compressor 1 exceeds a set value has been explained, but the present invention is not limited to this, and for example, the operation of the outdoor fan 3 is controlled. It may be configured such that the operation of the outdoor fan 3 is controlled according to an on/off pattern when the pressure on the high pressure side of the refrigeration cycle exceeds a set value.

[0029]

As explained above, the present invention controls the operation of the outdoor fan according to the on/off pattern preset according to the air conditioning load when the compressor current exceeds the set value. Since the system operates intermittently without completely stopping the operation, it is possible to raise the evaporation temperature by intermittently blowing outside air into the outdoor heat exchanger while controlling the capacity according to the heating load.

Therefore, it is possible to suppress the growth of frost on the outdoor heat exchanger, suppress the freezing of the fins, suppress or prevent the freezing noise, and improve quietness.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing an example of a control program for the high-pressure suppression control device shown in FIG. 2;

FIG. 2 is an overall configuration diagram of an embodiment of an air conditioner according to the present invention.

FIG. 3 is a graph showing the setting range of the compressor current in the high-pressure suppression control device shown in FIG. 2;

FIG. 4 is a timing chart showing the on/off pattern of the outdoor fan in this embodiment in comparison with a conventional example.

FIG. 5 is a graph showing fluctuations in the compressor current under the control of this embodiment in comparison with a conventional control example.

[Explanation of symbols]

1 Compressor 2 Four-way valve 3 Outdoor fan 4 Outdoor heat exchanger 5 Expansion valve 6 Indoor fan 7 Indoor heat exchanger 7a Indoor heat exchanger temperature sensor 8 Refrigerant piping 9 Room temperature sensor 10 Room temperature setting device 11 Detection sensor 12 High pressure suppression control device

Claims (1)

[Claims] Claim 1: An air conditioner in which a refrigeration cycle is constructed by sequentially connecting a compressor, a four-way valve, an indoor heat exchanger equipped with an indoor fan, a pressure reducer, an outdoor heat exchanger equipped with an outdoor fan, etc. with refrigerant piping. In the machine, during heating operation of the refrigeration cycle, when the current applied to the compressor or the temperature of the indoor heat exchanger exceeds a set value, operation of the outdoor fan is preset according to the air conditioning load. An air conditioner characterized by being provided with a high pressure suppression control means that controls according to an on/off pattern.