JPH01102253A - Air conditioner - Google Patents

Abstract

PURPOSE: To ensure stabilized operation of an outdoor fan regardless of outer wind by adding the signal from a pressure switching means operating in response to the delivery pressure of the outdoor fan to the r.p.m. thereof thereby controlling the r.p.m. of the outdoor fan. CONSTITUTION: Condensation temperature of refrigerant in an outdoor heat exchanger 3 is detected by a temperature detecting means and compared by a comparing means 8 with a reference set level. A calculated r.p.m. of an outdoor fan 10 is added with a signal from a pressure detecting means operating depending on the delivery pressure of the outdoor fan 10 and the output from the comparing means 8 is modified by an r.p.m. control means 9 based on the signal from pressure detecting means. The r.p.m. of the outdoor fan 10 is controlled to sustain the refrigerant condensing power of the outdoor heat exchanger 3 is kept at a substantially constant level.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an air conditioner, and particularly relates to an air conditioner that controls the rotation speed of an outdoor blower that blows outside air to an outdoor heat exchanger. be.

[Prior Art] FIG. 4 is a configuration diagram showing a conventional air conditioner disclosed in, for example, Japanese Patent Application Laid-open No. 133253/1983.

In the figure, (1) is a compressor for compressing refrigerant, (2) is a four-way valve that switches the refrigerant circulation route between cooling and heating operations, and (3) is a condenser that functions as a condenser during cooling operation and a heating An outdoor heat exchanger, which functions as an evaporator during operation, (4
) is a pressure reducing means such as an expansion valve or a capillary tube made of capillary tubes, and (5) is an indoor heat exchanger that functions as an evaporator during cooling operation and as a condenser during heating operation, contrary to outdoor heat exchanger (3). It is a vessel. (6) is a thermistor installed on the piping connecting the outdoor heat exchanger (3) and the pressure reduction means (4), and (7) is the A/R that converts the electrical resistance value detected by the thermistor (6) into a digital signal. The D conversion means (8) is a comparison calculation means (9) for comparing and calculating the digital signal from the A/D conversion means (7) and the reference set value.
) is a rotation speed control means for controlling the rotation speed of the outdoor blower based on the calculation result of the comparison calculation means (8), and (10) is an outdoor blower for blowing outdoor air to the outdoor heat exchanger (3).

A conventional air conditioner is configured as described above, and can be operated as a cooler or a heater by exchanging heat with an outdoor heat exchanger (3) and an indoor heat exchanger (5). The operation during this cooling operation will be explained below.

First, we will discuss the circulation of refrigerant. The high temperature, high pressure gaseous refrigerant discharged from the compressor (1) flows into the outdoor heat exchanger (3) via the four-way valve (2).

Here, the refrigerant exchanges heat with the outdoor air blown by the outdoor blower (10), is condensed, becomes a high-pressure liquid refrigerant, and is sent to the pressure reducing means (4). The refrigerant is depressurized by the decompression means (4) and sent to the indoor heat exchanger (5). Indoor heat exchanger (5)
The refrigerant evaporates in the overculm that passes through it, becoming a low-pressure gaseous refrigerant. Then, it returns to the compressor (1) via the four-way valve (2). In this way, the cooling cycle is configured.

At this time, the thermistor (6) installed near the outdoor heat exchanger (3) detects the -4= refrigerant condensation temperature in the outdoor heat exchanger (3) as an electrical resistance. This detection signal is converted into a digital signal by the A/D conversion means (7). Based on this conversion signal, the comparison calculation means (8) calculates and calculates the rotation speed of the outdoor blower (10). The rotation speed of the outdoor air blower 11 (10) is controlled by the rotation speed control means (9), and the condensation temperature detected by the thermistor (6) is controlled to a predetermined temperature.

For example, when the temperature of outdoor air decreases, the outdoor heat exchanger (
3) The condensing capacity of the refrigerant increases and the condensing temperature of the refrigerant also decreases. This decrease in condensation temperature is detected by the thermistor (6), and the comparison calculation means (8) and the rotation speed control means (9) are operated so that the detected temperature becomes a predetermined constant value.
The rotation speed of the outdoor blower (10) is controlled.

In this way, this type of air conditioner uses an outdoor heat exchanger (
Even when the temperature of the outdoor air at the installation part 3) decreases, the condensing capacity of the refrigerant of the outdoor heat exchanger (3) can be maintained substantially constant.

[Problems to be solved by the invention] In the conventional air conditioner as described above, an outdoor heat exchanger (3
), the rotational speed of the outdoor blower (10) is controlled in accordance with the condensation temperature of the refrigerant, and the refrigerant condensation capacity of the outdoor heat exchanger (3) is maintained substantially constant.

Therefore, when the temperature of the outdoor air decreases, the rotational speed of the outdoor air blower 1i1 (10) also decreases.

However, when the rotational speed of the outdoor blower (10) falls below a predetermined rotational speed, the outdoor blower (10) is easily affected by the outside wind. In particular, when receiving outside air from the outlet side of the outdoor blower (10), the air flow rate from the outdoor blower (10) decreases significantly and the discharge pressure of the outdoor blower (10) increases rapidly. There was a problem that the operation of the air conditioner became unstable.

Therefore, this invention was made to solve such problems, and an object of the present invention is to provide an air conditioner that can operate stably without being affected by outside wind or the like.

−6= [Means for Solving the Problems] The air conditioner according to the present invention detects the condensation temperature of the refrigerant in the outdoor heat exchanger (3) installed near the outdoor heat exchanger (3). Comparative calculation means (8) that calculates the rotation speed of the outdoor blower (10) by comparing and calculating the signal from the detection means and a reference setting value, and a pressure detection device that operates according to the discharge pressure of the outdoor blower (10). and a rotation speed control means (9) to change the output of the comparison calculation means (8) according to the signal of the pressure detection means to maintain the refrigerant condensing capacity of the outdoor heat exchanger (3) substantially constant. The number of rotations of the outdoor blower (10) is controlled as much as possible.

[Function] In the air conditioner of this invention, the outdoor heat exchanger (3)
Detecting the condensation temperature of the refrigerant with a temperature detection means, and comparing and calculating this detection signal with a reference setting value using a comparison calculation means (8),
The calculated rotation speed of the outdoor blower (10) is
10) is added to the signal from the pressure detection means that operates according to the discharge pressure, and the rotation speed control means (9) changes the output of the comparison calculation means (8) according to the signal from the pressure detection means, and the outdoor heat exchanger (3) The number of revolutions of the outdoor blower (10) is controlled to maintain the refrigerant condensing capacity substantially constant.

[Embodiment] FIG. 1 is a block diagram showing an air conditioner according to an embodiment of the present invention, and FIG. 2 is a block diagram showing a rotation speed control system of an outdoor blower of the air conditioner shown in FIG. In addition, in the figure, (1
) to (10) are components that are the same as or correspond to the components of the above-mentioned conventional example.

In the figure, (11) is a pressure switch that operates according to the discharge pressure of outdoor blower II (10), and is installed in the refrigerant pipe connecting the compressor (1) and the four-way valve (2). .

The pressure switch (11) is set to operate at a pressure higher than the pressure of the outdoor blower (10) during normal cooling operation, and is normally closed. However, the outside air to the outdoor heat exchanger (3), especially the outdoor heat exchanger (3)
When a certain amount of outside air arrives from the outlet side of the outdoor fan (10), the amount of air blown by the outdoor fan (10) decreases significantly, and the outdoor fan (
10) The discharge pressure increases rapidly. As a result, the pressure switch (11) becomes open.

The air conditioner of this embodiment is configured as described above, and both the condensation temperature of the refrigerant in the outdoor heat exchanger (3) detected by the thermistor (6) and the opening/closing signal of the pressure switch (11) are detected by the thermistor (6). The signal is used to control the rotation speed of the outdoor blower (10) (see Fig. 2).

The operation of the air conditioner of this embodiment during cooling operation will be described below. However, in this embodiment, the refrigerant circulation operation and the condensation temperature of the refrigerant in the outdoor heat exchanger (3) are detected by the thermistor (6), and the outdoor blower (10) is turned on to keep this temperature constant. The basic operation for controlling the rotational speed is the same as in the conventional example described above, so its explanation will be omitted.

Here, the rotation speed control of the outdoor blower (10) including the opening/closing operation of the newly added pressure switch (11) will be explained using FIG. 3. FIG. 3 is a flowchart showing the rotation speed control operation of the outdoor blower of the air conditioner shown in FIG.

First, in step S1, the rotation speed Nj of the outdoor blower (10) is
Set the initial rotation speed to NO and start operating the air conditioner. Next, in step S2, the thermistor (6) detects the condensation temperature TH of the refrigerant in the outdoor heat exchanger (3), and in step S3, the condensation temperature TH and the target refrigerant condensation temperature THO (reference set value) are determined. Find the temperature difference, dT.

Then, in step S4, when the pressure switch (11) is in an open state, a certain amount of outside air arrives from the outlet side of the outdoor heat exchanger (3), and the amount of air blown by the outdoor blower (10) decreases.
The pressure switch (11) is in an open state due to an increase in the discharge pressure of the outdoor blower (10), or
Determine whether it is in the normal closed state.

If the amount of air blown by the outdoor blower (10) has significantly decreased and the pressure switch (11) is in an open state, a signal is sent in step S5 to set the updated rotation speed N j+1 of the outdoor blower (10) to the maximum rotation speed N max. output to ensure a constant air volume against the outside wind.

On the other hand, if the normal pressure switch (11) is in the closed state,
In step S6, the rotational speed change ΔN according to the temperature difference ΔT
is calculated as ΔN=KX, JT.

However, K is a positive constant. ΔN during this change in rotational speed
Accordingly, in step S7, the updated rotational speed N j+1 of the outdoor blower (1o) is controlled as N j+1←Nj10dN.

At this time, if ΔT≧O, then JN≧O, so
The detection temperature TH of the thermistor (6) is the target condensation temperature TH
When the rotation speed is higher than O, the updated rotation speed Nj+1 is made larger than the previous rotation speed Nj, and the rotation speed of the outdoor blower (10) is increased. On the other hand, in the case of ΔToo, JN<O
Then, the updated rotation speed Nj is made smaller than the previous rotation speed Nj, and the rotation speed of the outdoor blower (10) is decreased.

This calculated updated rotation speed N j+ of the outdoor blower (10)
1 is compared with a predetermined maximum rotation speed N max of the outdoor blower (10) in step S8. And Nj41≧N
In the case of maX, N, Dl(-Nm
Set ax and output Nj+1=Nmax.

Further, in the case of Nj+1 <NmaX, step S9
The updated rotational speed Nj+1 calculated in is output. This operation is performed repeatedly and continuously.

In this way, in this embodiment, the outdoor blower is controlled by using both the condensation temperature signal of the refrigerant in the outdoor heat exchanger (3) detected by the thermistor (6) and the opening/closing signal of the pressure switch (11). (10) Since it controls the rotation speed,
The rotation speed of the outdoor blower (10) can be controlled without being affected by surrounding conditions such as outside wind. Since the condensing capacity of the refrigerant of the outdoor heat exchanger (3) can be maintained approximately constant, the temperature of the outdoor air decreases, and the outdoor blower (1)
Even when the rotation speed of 0> decreases, stable operation of the air conditioner can be ensured.

By the way, in the above embodiment, the thermistor (6) is used as the temperature detection means for detecting the condensation temperature of the refrigerant in the outdoor heat exchanger (3), but other temperature sensitive elements may be used.

In addition, the pressure switch (11) that operates according to the discharge pressure of the compressor (1) in the above embodiment is normally closed and becomes open when the discharge pressure of the outdoor blower (10) suddenly increases. Although a pressure sensor is used, a pressure detection means such as an ordinary pressure sensor may be used.

[Effects of the Invention] As explained above, the air conditioner of the present invention detects the condensation temperature of the refrigerant in the outdoor heat exchanger using the temperature detection means, and compares this detection signal with a reference setting value using the comparison calculation means. By adding a signal from the pressure switching means that operates according to the discharge pressure of the outdoor blower to the calculated rotation speed of the outdoor blower, the rotation speed of the outdoor blower is controlled by the rotation speed control means, and the rotation speed of the outdoor heat exchanger is controlled. Since it maintains the refrigerant condensing capacity at a constant level, it is possible to control the rotation speed of the outdoor fan without being affected by outside wind, so if the outdoor air temperature drops and the rotation speed of the outdoor fan decreases. It also ensures stable operation.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an air conditioner which is an embodiment of the present invention, FIG. 2 is a block diagram showing a rotation speed control system of an outdoor blower of the air conditioner shown in FIG. Flowcharts 1 to 4 showing the rotation speed control operation of the outdoor blower of the air conditioner shown in the figure are configuration diagrams showing a conventional air conditioner. In the figure, 3: outdoor heat exchanger, 6: thermistor, 8: comparison calculation means, 9: rotation speed control means, 10: outdoor blower, 11: pressure switch. In addition, in the figures, the same reference numerals and the same symbols indicate the same or equivalent parts.

Claims (3)

[Claims] (1) Temperature detection means arranged near the outdoor heat exchanger to detect the condensation temperature of the refrigerant in the outdoor heat exchanger, and a signal from the temperature detection means and a reference setting value are compared and calculated, and the difference is calculated. a comparison calculation means that calculates the rotational speed of the outdoor blower according to the rotation speed of the outdoor blower; a pressure detection means that operates according to the discharge pressure of the compressor; and an output of the comparison calculation means is changed according to a signal from the pressure detection means. An air conditioner comprising: a rotation speed control means for controlling the rotation speed of an outdoor blower to maintain a substantially constant refrigerant condensing capacity of the outdoor heat exchanger. (2) The temperature detection means installed near the outdoor heat exchanger to detect the condensation temperature of the refrigerant in the outdoor heat exchanger is a thermistor. Air conditioner. (3) A rotation speed control means for controlling the rotation speed of the outdoor blower in order to maintain the refrigerant condensing capacity of the outdoor heat exchanger substantially constant by changing the output of the comparison calculation means based on the signal of the pressure detection means. , when the pressure detection means detects an increase in pressure, the rotational speed of the outdoor fan is set to a predetermined maximum rotational speed, and when the pressure detection means detects a drop in pressure, the outdoor blower is set to a predetermined maximum rotational speed according to a signal from the temperature detection means. The air conditioner according to claim 1, characterized in that the rotation speed of the blower is controlled.