JPH08210720A - Air conditioner with refrigeratnt heater - Google Patents

Abstract

PURPOSE: To prevent the deterioration of refrigerant or the lubricating failure of the mechanism of a compressor in any heating state by providing a discharge pressure detecting sensor and a discharging refrigerant temperature detecting thermistor at the discharge side of a compressor. CONSTITUTION: A discharge pressure detecting sensor 12 and a discharge refrigerant detecting thermistor 13 are provided at the discharge side of a compressor 1. The refrigerant circulating amount of an air conditioner having a refrigerant heater 8, the refrigerant heating amount of the heater 8 or the flow rate of a pressure reducing unit 4 is so controlled that the superheat degree of the suction refrigerant of the compressor 1 is stabilized within a predetermined range. Thus, even in any state of heating, the superheat degree of the discharge refrigerant of the compressor 1 and the superheat degree of the suction refrigerant of the compressor 1 are held at the suitable degree even in any of the heating to prevent the decrease or the deterioration of the efficiency of the heater 8 and the lubricating failure of the mechanism of the compressor 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner equipped with a refrigerant heating device.

[0002]

2. Description of the Related Art An air conditioner equipped with a conventional refrigerant heating device has been disclosed, for example, in Japanese Unexamined Patent Publication No. 1-163563. The configuration will be described below with reference to FIGS.
Will be described with reference to. As shown in FIG. 5, the compressor 1,
The four-way valve 2, the indoor heat exchanger 3, the pressure reducer 4, the first check valve 5, the outdoor heat exchanger 6, and the second check valve 9 are connected in an annular shape, and the pressure reducer 4 and the first A refrigerant heating device 8 including a heat exchanger 8a and a burner 8b is connected to the suction side of the compressor 1 from between the check valve 5 and a two-way valve 7 to form a refrigeration cycle. The refrigerant circulates in the order of the machine 1, the indoor heat exchanger 3, and the refrigerant heating device 8. The indoor heat exchanger 3 radiates heat and the refrigerant heating device 8 absorbs heat. In addition, 10 is an indoor air temperature detecting thermistor, and 11 is an outlet refrigerant temperature detecting thermistor.

The refrigerant circulation amount G is the operating frequency Ga of the compressor 1.
As a variable capacity compressor capable of varying the temperature, in the heating operation, the operating frequency can be set in 11 steps from 5 g to 15 g for each g, and as shown in FIG.
And the operating temperature Ga of the compressor 1 is determined by the difference Td between the room temperature Ts detected by the room temperature detecting thermistor 10. Further, the refrigerant heating device 8 has a refrigerant heating amount Q.
Can be changed in 11 steps from 5q to 15q for each q, and as shown in FIG. 7, the operating frequency Ga of the compressor 1 can be changed.
The refrigerant heating amount Q is determined by. Further, the flow rate N of the pressure reducer 4 is set such that the flow rate N is 5 to 5n for every n.
As an electric expansion valve that can be varied in five steps up to, the flow rate N is determined by the operating frequency Ga of the compressor 1 as shown in FIG. Furthermore, the outlet refrigerant temperature Tl of the heat exchanger 8a of the refrigerant heating device 8 is set to the outlet refrigerant temperature detecting thermistor 11.
The temperature is controlled to stop heating when Tl becomes higher than the set temperature TH, and restarts when Tl becomes lower than the set temperature TL (TL <TH).

[0004]

In an air conditioner equipped with a refrigerant heating device as in the prior art, the compressor 1 during heating operation is used as a pump for circulating the refrigerant. Here, in order to secure a sufficient refrigerant circulation amount G and to make the input of the compressor 1 as small as possible, the compressor 1
It is necessary to increase the suction pressure to increase the suction refrigerant amount and reduce the discharge pressure of the compressor 1 to reduce the compression work.
Therefore, the flow rate N of the decompressor 4 must be increased or set close to the maximum so that the compression ratio of the compressor 1 becomes small. When the compression ratio of the compressor 1 is small, the change in the state amounts of the suction refrigerant and the discharge refrigerant is small, and the superheat degree S of the discharge refrigerant is S.
Hd also does not become much higher than the superheat degree SHs of the suction refrigerant. Here, the oil reservoir of the refrigerating machine oil that lubricates the mechanical portion of the compressor 1 is generally on the discharge side. However, when the degree of superheat of the refrigerant decreases, the compatibility of the refrigerant and the refrigerating machine oil sharply improves. When the superheat degree SHd of the discharged refrigerant is too small, a large amount of the refrigerant is dissolved in the refrigerating machine oil in the oil reservoir, the lubricating performance of the refrigerating machine oil is deteriorated, and poor lubrication occurs in the mechanical portion of the compressor 1.

Therefore, the superheat degree SH of the refrigerant discharged from the compressor 1
Since it is necessary to make d larger than a certain value, the superheat degree SHs of the suction refrigerant must be made large.

The suction of the compressor 1 and the outlet of the refrigerant heating device 8 can be regarded as the same position on the refrigeration cycle, and increasing the superheat degree SHs of the refrigerant sucked into the compressor 1 means that the refrigerant heating device is 8, the superheat degree SHh of the outlet refrigerant of the refrigerant heating device 8 is increased, but if the superheat degree SHh of the outlet refrigerant of the refrigerant heating device 8 is too large, the efficiency of the heat exchanger 8a of the refrigerant heating device 8 is reduced, and the local superheat This causes problems such as deterioration of the refrigerant due to.

Therefore, the refrigerant circulation amount G, the refrigerant heating amount Q of the refrigerant heating device 8 and the flow rate N of the decompressor 4 are determined by the superheat degree SHd of the refrigerant discharged from the compressor 1 and refrigeration by melting a large amount of the refrigerant in the refrigerating machine oil. It is not so small that the lubrication performance of machine oil deteriorates,
The superheat degree SHs of the refrigerant sucked into the compressor 1 is determined by the refrigerant heating device 8
It is necessary to set the heat exchanger 8a so as not to be so large that the efficiency of the heat exchanger 8a is deteriorated and the refrigerant is deteriorated due to local overheating.

However, in the air conditioner equipped with the conventional refrigerant heating device as described above, the operating frequency G of the compressor 1 is
a, in other words, the refrigerant circulation amount G, the refrigerant heating amount Q of the refrigerant heating device 8, and the flow rate N of the decompressor 4 are such that the refrigerant discharged from the compressor 1 is overheated when the indoor temperature is normal and the cycle is stable. The SHd is set to an appropriate size,
Further, the refrigerant heating device 8 is controlled so that the superheat degree SHs of the refrigerant sucked into the compressor 1, that is, the superheat degree SHh of the outlet refrigerant of the refrigerant heating device 8 does not become too large in the transition period.

Therefore, when the cycle is stable at room temperature and when the room temperature is high or when the indoor air volume is weakened, the heat radiation amount of the indoor heat exchanger 3 decreases and the refrigerant heating amount Q becomes excessive. When the superheat degree SHs of the refrigerant sucked into the compressor 1 becomes too large, that is, when the refrigerant circulation amount G is insufficient such as during cold start of heating operation, that is, when the superheat degree SHh of the refrigerant exiting the refrigerant heating device SHh. In the case where the value becomes too large, the superheat degree SHs of the refrigerant sucked into the compressor 1 is maintained at an appropriate level, the efficiency of the heat exchanger 8a of the refrigerant heating device 8 is reduced, and the refrigerant is deteriorated due to local overheating. The problem of can be prevented.

However, when the indoor heat exchanger 3 increases the heat radiation amount such as when the indoor temperature is low or when the indoor air volume is increased, and the refrigerant heating amount Q becomes too small, or when the heating is restarted when hot. When the superheat degree SHd of the refrigerant discharged from the compressor 1 becomes too small, such as when the refrigerant circulation amount G becomes excessive, the superheat degree SHd of the refrigerant discharged from the compressor 1 cannot be maintained at an appropriate level. In some cases, the lubrication performance of the refrigerating machine oil deteriorates, resulting in poor lubrication of the mechanical portion of the compressor 1.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to prevent the deterioration of the refrigerant and the poor lubrication of the mechanical portion of the compressor under any heating operation condition.

[0012]

To achieve the above object, the present invention provides a discharge pressure detecting sensor and a discharge refrigerant temperature detecting thermistor on the discharge side of a compressor.

Further, a heat exchanger saturation temperature detecting thermistor for detecting the saturation temperature is provided in the heat exchanger of the refrigerant heating device, and an outlet refrigerant temperature detecting thermistor is provided at the outlet of the refrigerant heating device.

[0014]

According to the present invention, the refrigerant circulation amount G of the air conditioner equipped with the refrigerant heating device, the refrigerant heating amount Q of the refrigerant heating device or the flow rate N of the pressure reducer is set to the superheat degree of the refrigerant sucked into the compressor. Is controlled so as to stabilize within a certain range, so that the superheat degree SHd of the refrigerant discharged from the compressor and the superheat degree SH of the refrigerant sucked into the compressor are controlled in any heating operation.
It is possible to keep both s at an appropriate size and prevent the efficiency of the refrigerant heating device from deteriorating, the deterioration of the refrigerant, and the poor lubrication of the mechanical portion of the compressor.

[0015]

【Example】

(Embodiment 1) Hereinafter, a first embodiment of the present invention will be described with reference to FIG.
The description will be made with reference to FIG. In addition, the same components as those described in the conventional example are denoted by the same reference numerals and the description thereof will be omitted.

FIG. 1 is a refrigeration cycle diagram of an air conditioner according to a first embodiment of the present invention. As shown in FIG. 1, the outlet refrigerant temperature detecting thermistor 11 is removed from the conventional refrigeration cycle, and a discharge pressure detecting sensor 12 is provided on the discharge side of the compressor 1.
And a thermistor 13 for detecting the discharged refrigerant temperature.

When the heating operation is started, the refrigerant circulation amount G, that is, the operating frequency Ga of the compressor 1 is determined from the difference Td between the indoor set temperature Ta and the indoor temperature Ts in the same manner as in the conventional example. Flow rate N of the decompressor 4 from the operating frequency Ga of
And the refrigerant heating amount Q of the refrigerant heating device 8 is determined, and this is used as an initial value for operation. Next, from the discharge refrigerant temperature of the compressor 1 detected by the discharge refrigerant temperature detecting thermistor 13, the saturation temperature obtained from the discharge refrigerant pressure of the compressor 1 detected by the discharge pressure detecting sensor 12 is subtracted to obtain the discharge refrigerant Derives the superheat degree SHd.

FIG. 2 is a diagram showing the superheat degree zone division of the refrigerant discharged from the compressor. After the start of operation, as shown in Figure 2,
When the superheat degree SHd of the refrigerant discharged from the compressor 1 is continuously deviated from the range of C for the set time t and is in the range of A, B, D, and E, as shown in Table 1, the compressor 1 The operating frequency Ga, the refrigerant heating amount Q of the refrigerant heating device 8, and the flow rate N of the pressure reducer 4 are changed.

[0019]

[Table 1]

That is, the superheat degree S of the refrigerant discharged from the compressor 1
When Hd becomes too large and falls within the range of D and E,
On the contrary, when the superheat degree SHd of the discharge refrigerant of the compressor 1 becomes too small and falls within the range of A and B so that the superheat degree SHd of the discharge refrigerant of the compressor 1 becomes small, the discharge refrigerant of the compressor 1 The settings of the operating frequency Ga of the compressor 1, the refrigerant heating amount Q of the refrigerant heating device 8 and the flow rate N of the pressure reducer 4 are changed so that the superheat degree SHd becomes large.

When the superheat degree SHd of the refrigerant discharged from the compressor 1 does not return to the range of C even if the set time t elapses after the setting is changed and the ranges of A, B, D, and E are still present, Table 1 Accordingly, the operating frequency Ga of the compressor 1, the refrigerant heating amount Q of the refrigerant heating device 8, and the flow rate N of the pressure reducer 4 are changed. This is repeated until the superheat degree SHd of the refrigerant discharged from the compressor 1 returns to the range of C, and the superheat degree SHd of the refrigerant discharged from the compressor 1 becomes C.
When returning to the range, keep the setting at that time.

After the setting is changed, the setting time t is provided until the next setting is changed. It takes some time for the state quantity of the refrigerant to change and stabilize after the setting is changed. This is because if the following changes are made before being reflected in the refrigerant state quantity, the refrigerant state quantity will hunt.

In this way, the superheat degree SHd of the refrigerant discharged from the compressor 1 can be stabilized within a certain range, but the compressor 1 is set by setting the flow rate N of the pressure reducer 4 to a maximum value.
When the compression ratio is reduced and the compressor 1 is used as a pump, the superheat degree SHd of the refrigerant discharged from the compressor 1 is small because the state quantities of the refrigerant sucked into the compressor 1 and the refrigerant discharged therefrom are small.
The fact that it is possible to stabilize the temperature within a certain range means that the degree of superheat S of the refrigerant sucked into the compressor 1 is inevitable.
This means that Hs can be stabilized within a certain range.

As described above, in the first embodiment, the superheat degree SHd of the refrigerant discharged from the compressor 1 is not so small that the refrigerant melts into the refrigerating machine oil in a large amount and the lubricating performance of the refrigerating machine oil deteriorates. Therefore, it is possible to prevent the lubrication failure of the mechanical portion of the compressor 1 from being maintained. In addition, the superheat degree SHs of the refrigerant sucked into the compressor 1, that is, the superheat degree SHh of the outlet refrigerant of the refrigerant heating device 8 may cause deterioration of the efficiency of the heat exchanger 8a of the refrigerant heating device 8 or deterioration of the refrigerant due to local overheating. It is maintained at an appropriate size that is not so large that it is prevented from deteriorating the refrigerant.

(Embodiment 2) Next, a second embodiment of the present invention will be described with reference to FIGS. In addition, the same components as those described in the conventional example are denoted by the same reference numerals and the description thereof will be omitted.

FIG. 3 is a refrigeration cycle diagram of the air conditioner of the second embodiment of the present invention. As shown in FIG. 3, a heat exchanger saturation temperature detecting thermistor 14 for detecting the saturation temperature of the heat exchanger 8a of the refrigerant heating device is added to the conventional refrigeration cycle.

When the heating operation is started, the refrigerant circulation amount G, that is, the operating frequency Ga of the compressor 1 is determined from the difference Td between the indoor set temperature Ta and the indoor temperature Ts in the same manner as in the conventional example. Flow rate N of the decompressor 4 from the operating frequency Ga of
And the refrigerant heating amount Q of the refrigerant heating device 8 is determined, and this is used as an initial value for operation. Next, from the outlet refrigerant temperature detected by the outlet refrigerant temperature detecting thermistor 11, the saturation temperature of the heat exchanger of the refrigerant heating device detected by the heat exchanger saturation temperature detecting thermistor 14 is subtracted to obtain the outlet of the refrigerant heating device 8. The superheat degree SHd of the refrigerant is derived.

Here, in the refrigeration cycle, the refrigerant heating device 8
The outlet of can be regarded as the same position as the inlet of the compressor 1,
The superheat degree SHd of the outlet refrigerant of the refrigerant heating device 8 has the same meaning as the superheat degree SHs of the suction refrigerant of the compressor 1.

FIG. 4 is a diagram showing the superheat degree zone division of the compressor suction refrigerant. As shown in FIG. 4, when the superheat degree SHs of the suction refrigerant of the compressor 1 is continuously deviated from the range of M from the range of M for a set time t after the start of operation As shown in Table 2, the operating frequency Ga of the compressor 1, the refrigerant heating amount Q of the refrigerant heating device 8, and the flow rate N of the pressure reducer 4 are changed.

[0030]

[Table 2]

That is, the superheat degree S of the refrigerant sucked into the compressor 1
When Hs becomes too large and falls within the range of N and O,
On the contrary, when the superheat degree SHs of the suction refrigerant of the compressor 1 becomes too small and falls in the range of K and L so that the superheat degree SHs of the suction refrigerant of the compressor 1 becomes small, the suction refrigerant of the compressor 1 The operating frequency Ga of the compressor 1, the refrigerant heating amount Q of the refrigerant heating device 8, and the flow rate N of the pressure reducer 4 are changed so that the superheating degree SHs of the compressor 1 becomes large.

When the superheat degree SHs of the refrigerant sucked into the compressor 1 does not return to the M range but remains within the K, L, N, and O ranges even after the set time t elapses after the setting change, 2, the operating frequency Ga of the compressor 1 and the refrigerant heating device 8
The settings of the refrigerant heating amount Q and the flow rate N of the pressure reducer 4 are changed.
This is repeated until the superheat degree SHs of the suction refrigerant of the compressor 1 returns to the range of M, and the superheat degree SH of the suction refrigerant of the compressor 1 is returned.
When s returns to the range of M, the current setting is maintained.

After the setting is changed, the set time t remains until the next setting is changed.
Is provided for the same reason as in the first embodiment.

In this way, the superheat degree SHs of the refrigerant sucked into the compressor 1 can be stabilized within a certain range, but the compressor 1 is compressed by setting the flow rate N of the pressure reducer 4 to a maximum value. When the ratio is reduced and the compressor 1 is used as a pump, the change in the state quantity of the suction refrigerant and the discharge refrigerant of the compressor 1 is small, so the superheat degree SH of the suction refrigerant of the compressor 1 is small.
The fact that s can be stabilized within a certain range means that the superheat degree SHd of the refrigerant discharged from the compressor 1 can be stabilized within a certain range. .

As described above, in the second embodiment, the superheat degree SHs of the refrigerant sucked into the compressor 1, that is, the refrigerant heating device 8
The superheat degree SHh of the outlet refrigerant is maintained at an appropriate size that is not large enough to cause deterioration of the efficiency of the heat exchanger 8a of the refrigerant heating device 8 and deterioration of the refrigerant due to local overheating, and prevents deterioration of the refrigerant. be able to. In addition, the superheat degree SHd of the refrigerant discharged from the compressor 1 is maintained at an appropriate size that is not so small that the refrigerant melts in a large amount in the refrigerating machine oil and the lubricating performance of the refrigerating machine oil deteriorates. It is possible to prevent poor lubrication.

[0036]

As is apparent from the above description, the present invention provides the refrigerant circulation amount G of the air conditioner by providing the discharge pressure detecting sensor and the discharge refrigerant temperature detecting thermistor on the discharge side of the compressor. By controlling the refrigerant heating amount Q of the refrigerant heating device or the flow rate N of the pressure reducer so that the degree of superheat of the refrigerant sucked into the compressor is stabilized within a certain range, the compressor can be operated in any heating operation. Superheat degree of discharge refrigerant SHd
It is possible to maintain both the superheat degree SHs of the refrigerant sucked into the compressor and the appropriate degree. Therefore, the superheat degree SHd of the discharged refrigerant becomes too small, and a large amount of the refrigerant dissolves in the refrigerating machine oil in the oil sump of the compressor to lower the lubrication performance of the refrigerating machine oil, resulting in poor lubrication of the mechanical portion of the compressor. In other words, it is possible to prevent the superheat degree SHs of the refrigerant sucked into the compressor from becoming too large and the efficiency of the heat exchanger of the refrigerant heating device from being lowered, and the refrigerant from being deteriorated due to local overheating.

[Brief description of drawings]

FIG. 1 is a refrigeration cycle diagram of an air conditioner according to a first embodiment of the present invention.

FIG. 2 is a diagram showing the superheat degree zone division of the refrigerant discharged from the compressor.

FIG. 3 is a refrigeration cycle diagram of an air conditioner according to a second embodiment of the present invention.

FIG. 4 is a diagram showing the superheat zone zones of the refrigerant sucked into the compressor.

FIG. 5 is a refrigeration cycle diagram of a conventional air conditioner.

FIG. 6 is a diagram showing the relationship between the difference between the indoor temperature and the set temperature and the compressor operating frequency.

FIG. 7 is a diagram showing the relationship between the compressor operating frequency and the refrigerant heating amount of the refrigerant heating device.

FIG. 8 is a diagram showing a relationship between a compressor operating frequency and a pressure reducer flow rate.

[Explanation of symbols]

 1 Compressor 3 Indoor Heat Exchanger 4 Decompressor 6 Outdoor Heat Exchanger 8 Refrigerant Heating Device 8a Heat Exchanger 11 Outlet Refrigerant Temperature Detection Thermistor 12 Discharge Pressure Detection Sensor 13 Discharged Refrigerant Temperature Detection Thermistor 14 Heat Exchanger Saturation Temperature Thermistor for detection

Claims (2)

[Claims] 1. An air conditioner comprising a compressor, an indoor heat exchanger, a pressure reducer, an outdoor heat exchanger, and a refrigerant heating device connected in an annular shape, and a discharge pressure detecting sensor on a discharge side of the compressor. An air conditioner provided with a refrigerant heating device provided with a thermistor for detecting a discharged refrigerant temperature. 2. An air conditioner comprising a compressor, an indoor heat exchanger, a pressure reducer, an outdoor heat exchanger, and a refrigerant heating device connected in a ring shape, and a saturation temperature is detected in the heat exchanger of the refrigerant heating device. An air conditioner comprising a heat exchanger saturation temperature detecting thermistor and a refrigerant heating device provided with an outlet refrigerant temperature detecting thermistor at the outlet of the refrigerant heating device.