JPH0522769Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a heat pump refrigeration cycle with a heat storage device.

[Conventional technology]

In an air source heat pump, if heating operation is continued, frost will form on the outdoor heat exchanger under certain outside air conditions. As the accumulation of frost increases, the heat absorption effect of the outdoor heat exchanger is inhibited, resulting in inefficient operation. For this reason, it is necessary to perform a defrosting operation, and there are various defrosting methods. As an example of these, a refrigeration cycle can be considered in which a refrigeration cycle having a heat storage device is used to store heat during heating operation, and the heat storage device is used as a heat source during defrosting operation.

[Problem that the invention attempts to solve]

Since such a heat pump with a heat storage device normally stores heat during heating operation, unnecessary heat storage may occur even under operating conditions that do not require defrosting.

Furthermore, in a state where the temperature of the heat storage material is not sufficiently controlled within a predetermined temperature range, the defrosting cycle may not be performed smoothly due to excessive or insufficient amount of heat storage. In other words, if the amount of heat storage is small, defrosting may not be completed within the specified time, resulting in unmelted frost, or if the amount of heat storage is large, the high pressure during defrosting operation may rise abnormally, causing the refrigeration compressor to Protective devices may be activated.

It is an object of the present invention to solve the above-mentioned conventional problems and to provide a heat pump refrigeration cycle with a heat storage device that can secure just the right amount of heat storage under operating conditions that require defrosting.

[Means for solving problems]

The heat pump refrigeration cycle with a heat storage device according to the present invention is connected in parallel to a refrigeration compressor, a four-way valve, an indoor heat exchanger, a throttling device, an outdoor heat exchanger, and a circuit connecting the outdoor heat exchanger and the compressor. When defrosting frost that has formed on the outdoor heat exchanger, a part of the high-temperature, high-pressure refrigerant gas from the compressor is passed through a bypass circuit for outdoor heat exchange. In a heat pump refrigeration cycle in which the refrigerant is passed through the heat storage heat exchanger and the refrigerant is passed through the heat storage heat exchanger to utilize the heat absorption effect from the heat storage heat exchanger, depending on the outdoor air temperature and the outdoor air relative humidity,
or a frost formation detection means for detecting frost formation conditions based on the temperature of the outdoor heat exchanger; and when the frost formation detection means detects the frost formation conditions on the outdoor heat exchanger, the temperature of the heat storage material of the heat storage heat exchanger is determined. and a control means for controlling the heating means so that the temperature of the heat storage material falls within a set range. In addition to controlling the heating means, using a measuring means for detecting the temperature of the outdoor heat exchanger, a measuring means for outdoor air temperature, a measuring means for outdoor relative humidity, etc.
When the temperature of the outdoor heat exchanger is below a predetermined value, or when the outside temperature and the relative humidity of the outside air are within a predetermined range, the heating means for the heat storage material is energized.

[Effect]

Frost usually forms on the outdoor heat exchanger when the surface temperature of the outdoor heat exchanger is below 0°C, or when the outside air temperature is below 5°C and the outside air relative humidity is over 70%. According to the present invention, in addition to energizing the heat storage material under such conditions, the temperature of the heat storage material is detected so that the heat storage amount matches the load heat required for defrosting, and the temperature is kept within a set value. control.

〔Example〕

FIG. 1 is a diagram showing an embodiment of the present invention.
is a refrigeration compressor, 2 is a four-way switching valve, 3 is an indoor heat exchanger, 4 is an indoor blower, 5 is a throttling device, 6 is an outdoor heat exchanger, 7 is an outdoor blower, 8 is a two-way valve,
9 is a two-way valve, 10 is a heat storage device, 11 is a heat storage heat exchanger, 12 is a two-way valve, 13 is a heater for heating the heat storage material,
14 is an electrical contact, 15 is a thermistor for detecting the temperature of the heat storage material, 16 is a thermistor for detecting the outdoor air temperature, 1
7 is an outdoor air relative humidity detection sensor, 18 is A/
D converter, 19 is an A/D converter, 20 is an A/D converter, 21 is a microcomputer, 22 is an auxiliary expansion device, 23 is an electronic control unit for controlling the heat storage material temperature,
Reference numeral 24 indicates an outdoor unit of the air source heat pump, and 25 indicates an indoor unit of the air source heat pump.

In FIG. 1, a heat accumulator 10 contains a heat accumulating material such as paraffin or molten salt. Furthermore, a heating heater 13 for heating the heat storage material and a heat storage heat exchanger 11 for exchanging heat between the refrigerant and the heat storage material are provided. A storage heat exchanger 11, an auxiliary throttle device 22, and a two-way valve 9 connected in series are installed in parallel with the piping from the outdoor heat exchanger 6 to the four-way valve 2.

Further, a detection thermistor 15 for detecting the temperature of the heat storage material, a thermistor 16 for detecting the outside temperature, and a detection sensor 17 for detecting the outside air relative humidity are connected to the A/D converters 18, 19, 20.
It is connected to the microcomputer 21 via the microcomputer 21 and further connected to the electrical contact 14 of the heater 13.

The operation of the above embodiment of the present invention will be explained.

In FIG. 1, during heating operation, the two-way valve 9,
12 are both closed, and the two-way valve 8 is open. At this time, the refrigerant circulates as shown by the solid arrow →. That is, the high temperature and high pressure refrigerant compressed by the refrigeration compressor 1 enters the indoor heat exchanger 3 via the four-way switching valve 2. Here, it is cooled and condensed by the indoor blower 4, and performs a heating effect on the indoor space. Further, the condensed and liquefied refrigerant is depressurized by the expansion device 5 and enters the outdoor heat exchanger 6 as a low-temperature, low-pressure liquid refrigerant. Here, it is heated by the heat in the atmosphere by the outdoor side blower 7, evaporates, and is sucked into the refrigeration compressor 1 via the two-way valve 8 and the four-way switching valve 2. During this heating cycle, refrigerant does not accumulate because the regenerative heat exchanger 11 is connected to the suction side of the refrigeration compressor 1 through the four-way switching valve 2. Electronic control unit 23 for heat storage material temperature control
is microcomputer 21 and A/D converter 1
Consists of 8, 19 and 20. The outdoor unit 24 of the air source heat pump consists of an indoor refrigeration cycle and an electronic control unit 23 for controlling the temperature of the heat storage material. During this heating cycle, the heat storage 10 is heated by the heating heater 13.
heated by.

FIG. 2 is a block diagram of the control circuit of the embodiment shown in _FIG .
9 is an outdoor air relative humidity RH measurement means, 30 is a predetermined value storage circuit, 31 is a comparison means, and 32 is a heat storage temperature.
T _S measuring means, 33, heat storage temperature T _S setting means, 3
4 is a reference value calculation means; 35 is an on-point comparison means; 3
6 is an off point comparison means.

In Figures 1 and 2, the outdoor air temperature
T ₀ is detected by outdoor air temperature T ₀ measuring means 26 such as a thermistor 16 and an A/D converter 19 . Furthermore, this value is compared with a predetermined value (usually 5° C.) stored in advance in the predetermined value storage circuit 27 by the comparison means 28, and when the outdoor air temperature T ₀ is lower than the predetermined value, a signal is sent to start the operation of the heating heater 13. issue. In addition, the outdoor air relative humidity RH is determined by the humidity detection sensor 17, A/D converter 20, etc.
It is detected by the RH measuring means 29. Furthermore, this value is compared with a predetermined value (usually 70%) stored in advance in the predetermined value storage circuit 30 by the comparison means 31, and when the outdoor air humidity RH is higher than the predetermined value, a signal to start operation of the heating heater 13 is sent. put out. Furthermore, the temperature T _S of the heat storage device 18 etc. is determined by the thermistor 15, A/
It is detected by a T _S measuring means 32 such as a D converter 18 . At this time, the setting of the target value of the heat storage material temperature is
This is set by the T _S setting means 33, and based on this, the on point and off point are set by the reference value calculating means 34. When the temperature of the heat storage material is below the on-point, the on-point comparison means 35 operates, and the heating heater 13
When the off point is higher than the off point, the off point comparison means 36 is activated to issue a signal to stop the operation of the heater 13. In this way, the temperature of the heat storage material is controlled to be within the differential temperature difference between the on point and the off point. At this time, the heating heater 13 is operated and stopped by issuing commands to the electrical contacts 14 by the microcomputer 21.

Next, when the accumulation of frost in the outdoor heat exchanger 6 increases, a defrosting start signal is issued and defrosting operation begins. During defrosting operation, the two-way valves 9 and 12 are opened and the two-way valve 8 is closed. The refrigerant circulates as shown by the dotted arrow...→. That is, the high temperature and high pressure refrigerant discharged from the refrigeration compressor 1 is
Injected into the outdoor heat exchanger 6 via the two-way valve 12,
Here, heat is radiated and condensed, and it also contributes to the frost melting action. Next, the condensed and liquefied refrigerant passes through the two-way valve 9 and the auxiliary throttling device 22 and enters the heat storage heat exchanger 11, where it absorbs heat from the heat storage material heated to a predetermined temperature and evaporates. This evaporated refrigerant is sucked into the refrigeration compressor 1 through the four-way switching valve 2.

In the above example, the outside air temperature T ₀ and the outside air relative humidity RH
Frost formation on the outdoor heat exchanger is predicted by the detection of This is because, as shown in FIG. 3, the outside air conditions that cause frost to form on the outdoor heat exchanger are known in advance as the characteristics of the air source heat pump.

FIG. 4 is a diagram showing another embodiment of the present invention.
The same parts as those shown in the figures will be described with the same reference numerals. In the example shown in Fig. 1, we have described an example in which frost formation on the outdoor heat exchanger is predicted by detecting the outside air temperature _T0 and the outside air relative humidity RH. This is an example of predicting frost formation on the exchanger by detecting the temperature of the outdoor heat exchanger. Therefore, what is shown in FIG. 4 is the same as that shown in FIG. 1 except that the outdoor air relative humidity detection sensor 17 and the A/D converter 20 are removed, and the outdoor air temperature detection thermistor 16 in FIG. In place of the A/D converter 19, a thermistor 16' for detecting the temperature of the outdoor heat exchanger and an A/D converter 19' are provided. section 23' and outdoor unit 2
4', with the other changes being the same as those explained with reference to FIG. 1.

FIG. 5 is a block diagram of the control circuit of the embodiment shown in FIG. 4, in which 26' is an outdoor heat exchanger T _E measurement means, 27' is a predetermined value storage circuit, and 28' is a comparison means. Each part is 26 to 31 in Figure 2.
These are provided in place of the parts shown in . The other parts are the same as those described with reference to FIG.

4 and 5, the outdoor heat exchanger temperature T _E , the thermistor 16', and the A/D converter 19'
It is detected by a T _E measuring means 26' such as TE measuring means 26'. Furthermore, this value is compared with a predetermined value (usually 0° C.) stored in advance in the predetermined value storage circuit 27' by the comparison means 28', and if T _E is lower than the predetermined value, a signal is sent to start operation of the heater 13. issue. Further, the temperature T _S of the heat storage device is detected by a T _S measuring means 32 such as a thermistor 15 and an A/D converter 18 .
At this time, the target value of the heat storage material temperature is set by the T _S setting means 33, and based on this, the on point and the off point are set by the reference point calculating means 34. When the temperature T _S of the heat storage material is below the ON point, a signal to start operation of the heater 13 is issued, or when it is above the OFF point, a signal to stop the operation of the heater 13 is issued. In this way, the temperature of the heat storage material is controlled to be within the differential temperature difference between the on point and the off point. At this time, the heating heater 13 is operated and stopped by issuing a command to the electric contact 14 from the microcomputer 21'.

Next, when the accumulation of frost in the outdoor heat exchanger 6 increases, a defrosting start signal is issued and defrosting operation begins. During defrosting operation, the two-way valves 9 and 12 are opened, and the two-way valve 8 is closed. The refrigerant circulates as shown by the dotted arrow...→. That is,
The high-temperature, high-pressure refrigerant discharged from the refrigeration compressor 1 is injected into the outdoor heat exchanger 6 via the two-way valve 12, where it radiates heat and condenses, contributing to the defrosting action. Next, the condensed and liquefied refrigerant passes through the two-way valve 9 and the auxiliary throttling device 22 and enters the heat storage heat exchanger 11, where it absorbs heat from the heat storage material heated to a predetermined temperature and evaporates. This evaporated refrigerant is sucked into the refrigeration compressor 1 through the four-way switching valve 2.

[Effect of idea]

According to the present invention, electricity is applied to the heat storage device in the temperature range where frost formation occurs on the outdoor heat exchanger, and heat can be stored only when defrosting is truly required. Since the temperature is controlled within the set temperature and its differential to reach the optimum amount required for the defrosting, excellent effects such as a smooth defrosting cycle can be achieved.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the configuration of an embodiment of the present invention, Fig. 2 is a block diagram of the control circuit of the embodiment shown in Fig. 1, and Fig. 3 is a diagram showing the relationship between outside air temperature and outside air relative humidity. , FIG. 4 is a diagram showing the configuration of another embodiment of the present invention, and FIG. 5 is a block diagram of the control circuit of the embodiment shown in FIG. 4. 10... Heat storage device, 11... Heat storage heat exchanger, 13
... Heater for heating the heat storage material, 15 ... Thermistor for detecting the temperature of the heat storage material, 16 ... Thermistor for detecting the outdoor air temperature, 16' ... Thermistor for detecting the temperature of the outdoor heat exchanger, 17 ... ... Thermistor for detecting the outdoor air relative humidity sensor, 23, 23' electronic control unit for controlling the temperature of the heat storage material.

Claims (1)

[Scope of utility model registration request] A regenerative heat exchanger having a refrigeration compressor, a four-way valve, an indoor heat exchanger, a throttling device, an outdoor heat exchanger, and a heating means connected in parallel to a circuit connecting the outdoor heat exchanger and the compressor. When defrosting the frost that has formed on the outdoor heat exchanger, part of the high-temperature, high-pressure refrigerant gas from the compressor is passed through the bypass circuit to the outdoor heat exchanger, and at the same time, the refrigerant is supplied to the storage heat exchanger. In a heat pump refrigeration cycle in which the heat absorption effect from the heat storage heat exchanger is utilized by flowing the heat exchanger, a frost formation detection means detects frost formation conditions by the outdoor air temperature and the outdoor air relative humidity, or by the temperature of the outdoor heat exchanger. and a control means for controlling the heating means so that the temperature of the heat storage material of the heat storage heat exchanger falls within a set range when the frost formation detection means detects a frost formation condition on the outdoor heat exchanger. A heat pump refrigeration cycle with a heat storage device.