JPH0115786B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention is a heat pump type refrigeration system, more specifically, it is equipped with a heat source side heat exchanger and a user side heat exchanger, and an expansion mechanism and a gas-liquid separation device are provided in the middle of the refrigerant piping connecting these two heat exchangers. The present invention relates to a heat pump type refrigeration system which is configured to inject intermediate pressure refrigerant in the expanding process from the gas region of the separator into the compressor, and to perform heating and cooling by reversing the circulation direction of the refrigerant. (Prior art) Conventionally, in a heat pump type refrigeration system, the fourth
As shown in the figure, an expansion mechanism is divided and installed in the middle of the refrigerant pipe connecting the user side heat exchanger H and the heat source side heat exchanger I, and a gas-liquid separator A is installed between these expansion mechanisms. An injection tube O is connected to the gas-liquid separator A, and the gas refrigerant separated by the gas-liquid separator A is injected into the compressor J to increase heating capacity. For example, it is known as shown in Japanese Patent Application Laid-Open No. 17017/1983. In addition, what is shown in FIG. 4 is the gas-liquid separator A.
In order to improve gas-liquid separation during heating and cooling,
An inlet pipe B is provided at the upper part of the gas-liquid separator A, and an outlet pipe C is provided at the lower part, and the first expansion mechanism D for cooling and the first expansion mechanism D for heating are provided both during cooling and heating when the refrigerant circulation direction is reverse cycle. 1. The liquid-gas mixed refrigerant that has passed through the expansion mechanism E and has been reduced to an intermediate pressure is introduced into the upper part of the separator A from the inlet pipe B, and the separated liquid refrigerant is led out from the outlet pipe C. It is configured to reach the user side or heat source side heat exchanger H or I via the second expansion mechanism F for cooling and the expansion mechanism G for heating. In addition, in Fig. 4, P is a four-way switching valve, K, L,
M and N are check valves. On the other hand, in the heat pump type refrigeration system configured as described above, the optimum refrigerant circulation amount during cooling and heating is different, and if there is an excess or deficiency of this optimum refrigerant circulation, the heating and cooling capacity cannot be maximized and the energy efficiency is reduced. The energy efficiency ratio (EER) also decreases, and even if you occasionally perform angle injection during heating, you will not be able to fully demonstrate your performance. For this reason, conventionally, a charge modulator has been used to adjust the amount of refrigerant circulated during heating and cooling. (Problems to be Solved by the Invention) According to the conventional example shown in FIG. Since the refrigerant is circulated through the outlet pipe C, it is necessary to switch the flow during cooling and heating, where the refrigerant circulation direction is different. As a result, as shown in FIG. 11, a large number of check valves K, There was a problem in that L, M, and N were required, and the piping structure was complicated. In addition, as the number of check valves increases and the piping structure becomes more complex, the number of locations for brazing increases, which together with the increase in the number of parts increases costs and increases the cause of failure. Therefore, maintenance and inspection become complicated. Therefore, to solve the above problem, an inlet/outlet pipe is formed that becomes an inlet pipe during cooling and an outlet pipe during heating, and an inlet/outlet pipe becomes an outlet pipe during cooling and an inlet pipe during heating. , it is conceivable to arrange the refrigerant at the bottom of the gas-liquid separator, but there are problems in that the gas-liquid separation performance deteriorates and the separated liquid refrigerant cannot be extracted, and the above-mentioned problems cannot be fundamentally solved. It is. That is, when each of the inlet and outlet pipes are opened at the same level in the separator, if the opening height is set below the liquid level height, the liquid-gas mixed refrigerant from the inlet and outlet pipes (decompressed to intermediate pressure) The introduction of the liquid (due to its expansion) disturbs the liquid level, which drastically reduces the gas-liquid separation performance.In addition, if the opening height of each inlet/outlet pipe is made higher than the liquid level, the separation This means that the liquid refrigerant cannot be led out from the inlet/outlet pipe serving as the outlet pipe at an appropriate liquid level height. Then, by changing the opening height of each of the inlet/outlet pipes, making the opening height of one of the inlet/outlet pipes less than the liquid level height and the opening height of the other inlet/outlet pipe higher than the liquid level, separation performance can be improved, for example, during cooling. Even if the temperature is good, the separation performance deteriorates during heating, and moreover, the separated liquid refrigerant cannot be discharged at an appropriate liquid level. Therefore, even if the above-mentioned problems can be solved by arranging the two inlet and outlet pipes at the bottom of the separator as described above, the separation performance may be extremely poor, or the separated liquid refrigerant may not be heated to the proper liquid level. Therefore, other problems arise that cannot be solved under such circumstances, and the above-mentioned problem cannot be fundamentally solved. On the other hand, in order to adjust the amount of refrigerant circulation during cooling and heating, a charge modulator is conventionally used, which poses the problem of high costs. An object of the present invention is to minimize the number of check valves in the above-mentioned refrigeration system, simplify the piping structure around the gas-liquid separator, and improve the gas-liquid separation performance of the gas-liquid separator. The separated liquid refrigerant can be discharged at an appropriate liquid level during both cooling and heating, and the refrigerant circulation amount during cooling and heating can be adjusted to the same level as the gas-liquid refrigerant without using a charge modulator. This allows for adjustment using a separator. (Means for Solving the Problems) In order to solve the above-mentioned conventional problems, the present invention includes a heat source side heat exchanger 4 and a user side heat exchanger 3, and connects both heat exchangers 3 and 4. An expansion device 5 and a gas-liquid separator 6 are interposed in the middle of the connecting refrigerant pipes, and intermediate pressure refrigerant in the expansion process is injected from the gas region of the separator 6 to the compressor 1 via an injection tube 9. In the heat pump type refrigeration system, which is capable of heating and cooling by setting the circulation direction of the refrigerant in a reverse cycle, the gas-liquid separator 6 includes:
A first inlet/outlet pipe 6 communicating with the heat source side heat exchanger 4
1 and a second inlet/outlet pipe 62 communicating with the utilization side heat exchanger 3 are arranged upward from the lower part of the separator 6, and these inlet/outlet pipes 61, 62
A plurality of through holes 63 and 64 are provided that open into the interior of the separator 6, while the inlet and outlet pipes 61,
62, the lowest position of the through hole 63 in the first inlet/outlet pipe 61, which becomes the inlet pipe during cooling and the outlet pipe during heating, is penetrated in the second inlet/outlet pipe 62, which becomes the outlet pipe during cooling and becomes the inlet pipe during heating. The lowest position of the hole 64 is the upper position, and the liquid level of the liquid refrigerant separated and stored in the gas-liquid separator 6 is higher during cooling than during heating. (Function) First and second inlet/outlet pipes 61, 62 communicating with the user side and heat source side heat exchangers 3, 4 are disposed upward from the bottom of the gas-liquid separator 6, and each of these inlet/outlet pipes 6
1 and 62 are provided with a plurality of through holes 63 and 64, the liquid-gas mixed refrigerant is introduced into the separator 6 from the through holes above the liquid level during heating and cooling without disturbing the liquid level. Therefore, while the minimum number of check valves can be reduced to two, the separation effect is also enhanced, and by setting the lowest positions of the through holes 63 and 64, each of the inlet and outlet pipes 61 and 62 can be used during heating and cooling. By utilizing the fact that the gas-liquid separator 6 functions as an inlet pipe and an outlet pipe, the gas-liquid separator 6 can be provided with a refrigerant amount adjustment function, and can be operated with an optimal refrigerant circulation amount during cooling and heating. be. (Example) Examples of the present invention will be described below based on the drawings. The refrigeration system of the present invention, as schematically shown in FIG. 4 (hereinafter referred to as an outdoor coil), an expansion device 5, a gas-liquid separator 6 interposed in the middle of the expansion device 5, and an storage unit 7, and the compressor 1 controls the capacity of the compressor 1. By switching the four-way switching valve 2, a cooling cycle shown by the solid line arrow in FIG. 1 and a heating cycle shown by the dotted line arrow are formed. In addition, an injection tube 9 is connected to the gas region of the gas-liquid separator 6 so that the gas region of the gas-liquid separator 6 can be connected to the compressor 1 and the expansion device 5 can perform cooling or heating. The intermediate pressure refrigerant in the expansion process is injected. The capacity control mechanism 8 is not a main part of the present invention, but to roughly explain the example shown in FIG. and a bypass passage 1 whose other end opens to an intermediate port 14 provided at an intermediate portion between the suction port 12 and the discharge port 13 of the cylinder chamber 11.
5 is provided in the bypass passage 15, and the passage 1 is connected to the bypass passage 15.
5 is provided with an on-off valve 16 that opens and closes the on-off valve 16.
is biased in the opening direction by a spring 17, the injection extension tube 9 is connected to the back chamber 18 of the opening/closing valve 16, and a solenoid valve 19 is interposed in the middle of the injection extension tube 9. It is something. The on-off valve 16 mainly uses a metal poppet valve and forms a control passage 16a in the center thereof.By opening the solenoid valve 19, the intermediate pressure gas in the gas region of the separator 6 is removed. The refrigerant or liquid-gas mixed refrigerant is introduced into the back chamber 18 of the on-off valve 16 through the injection tube 9, and the on-off valve 16 is closed. In this case, the bypass passage 15 is closed and the compressor 1 performs rated operation, but intermediate-pressure gas refrigerant or liquid-gas mixed refrigerant flows into the cylinder chamber 11 from the control passage 16a of the on-off valve 16. Since it is pushed in, the amount of circulation increases, and the amount of discharge increases, making it possible to operate with increased capacity. Furthermore, when the electromagnetic valve 19 is closed, the pressure in the rear chamber 18 becomes the same as the pressure in the intermediate port 14 of the cylinder chamber 11 due to the control passage 16a, so that the opening/closing valve 1
6 is opened, the bypass passage 15 is opened, and capacity control is performed. That is, by opening the bypass passage 15, no compression is performed between the suction port 12 and the intermediate port 14 of the compressor 1.
Capacity control is performed in which the capacity of the cylinder chamber 11 is reduced and the discharge amount is reduced. The opening and closing of the solenoid valve 19 is controlled according to the load. Generally, during rated operation during cooling, the solenoid valve 19 is closed and the bypass passage 15 is opened to perform capacity control operation, and during heating In the rated operation, the electromagnetic valve 19 is opened, intermediate pressure gas refrigerant is injected through the injection exit tube 9, and the on-off valve 16 is closed to perform increased capacity operation. Incidentally, even during cooling, capacity increasing operation can be performed by opening the electromagnetic valve 19, and capacity control operation can be performed by closing the electromagnetic valve 19 during heating. The capacity increase operation described above will be explained using the Mollier line shown in FIG. In this capacity-up operation, the solenoid valve 19 is opened, the on-off valve 16 is closed, and the control passage 16 is closed.
This is done by injecting the intermediate pressure gas refrigerant from a, and when the amount of refrigerant to be injected is g and the amount of circulation is G, the amount of discharge from the compressor 1 is G+
g, and increases by the above-mentioned injection amount g. The intermediate-pressure liquid refrigerant separated in the separator 6 approaches the saturated liquid line as shown in the Mollier diagram in Figure 3, and the evaporation capacity is Δi (Kcal/Kg ). Therefore, in the refrigeration system configured as described above, the expansion device 5 is configured by two first and second expansion device sections 51 and 52, and an intermediate portion between these first and second expansion device sections 51 and 52. The gas-liquid separator 6 is interposed in the separator 6.
The separator 6 has a cylindrical body 60 closed at the top and bottom, and the separator 6 includes a first inlet/outlet pipe 61 that communicates with the outdoor coil 4 via the first expansion device part 51, and A second inlet/outlet pipe 62 communicating with the indoor coil 3 via the second expansion device part 52 is disposed upward from the lower part of the separator 6, and an upper part of the separator 6 is provided with the compressor. An injection tube 9 communicating with the machine 1 is provided, and each of the first
The second inlet/outlet pipes 61, 62 are provided with a plurality of through holes 6 that open into the interior of the separator 6 as shown in FIG.
3, 64, while providing the lowest position of the through hole 63 in the first inlet/outlet pipe 61 which becomes an inlet pipe during cooling and an outlet pipe during heating among the first and second inlet/outlet pipes 61, 62, The lowest position of the through hole 64 in the second inlet/outlet pipe 62, which becomes the outlet pipe during cooling and the inlet pipe during heating, is set as the upper position, and the liquid level height of the liquid refrigerant separated and stored in the gas-liquid separator 6 is determined. The liquid level height h ₂ during cooling is configured to be higher than the liquid level height h ₁ during heating. That is, the optimum refrigerant circulation amount during cooling and heating is different. In general, when the amount of refrigerant at which the cooling capacity (Kcal/h) reaches the maximum (2250Kcal/h) is 1400〓,
Maximum heating capacity (Kcal/h) (3300Kcal/h)
The amount of refrigerant required is 1500〓, and there is a difference of 100〓.If there is an excess or deficiency of the optimal refrigerant amount, the heating and cooling capacity cannot be maximized and the effective energy ratio (EER) will also decrease. Therefore, conventionally, a charge modulator or the like has been used to adjust the amount of refrigerant. Therefore, the cost is high, but by configuring as described above, it is possible to adjust the amount of refrigerant during cooling and heating without using any special configuration. There are also some systems that do not use an adjustment mechanism, sacrificing a reduction in capacity and EER, but in this case, excess refrigerant during cooling is stored in the accumulator, and as a result, the evaporator The indoor coil 3 is no longer used effectively, the degree of superheat is lost, and the cooling capacity and EER decrease.However, as mentioned above, if the excess refrigerant during cooling is stored in the separator 6, the excess refrigerant This prevents the refrigerant from flowing into the indoor coil 3, increasing the degree of superheating and improving the cooling capacity and EER as shown in the table below. The following table () shows the case where the amount of refrigerant is not adjusted, and () shows the case where the amount of refrigerant is not adjusted.
This is the case when the amount of refrigerant is adjusted.

[Table] In addition, in the above configuration, each of the first and second
The expansion device parts 51 and 52 each consist of two expansion mechanisms mainly consisting of capillary tubes and one check valve. 1 expansion mechanism 53 and a cooling expansion mechanism 54, each of these expansion mechanisms 53 and 54 are connected in series, and one check valve 55 is connected in parallel to the cooling expansion mechanism 54. In addition, the second expansion device section 52 includes a second expansion mechanism 56 that operates during cooling and heating, and a heating expansion mechanism 57, and these expansion mechanisms 56 and 57 are connected in series to One check valve 58 is connected to the expansion mechanism 57 in parallel. Therefore, during cooling, the first and second expansion mechanisms 53 and 56 and the cooling expansion mechanism 54 are used, and during heating, the first and second expansion mechanisms 53 and 56 and the heating expansion mechanism 57 are used. During cooling, the liquid-gas mixed refrigerant, which has been reduced to an intermediate pressure through the two expansion mechanisms 53 and 54 in the first expansion device section 51, flows from the first inlet/outlet pipe 61 to the through hole 63 of the first inlet/outlet pipe 61. The gas refrigerant and the liquid refrigerant are separated in the separator 6, and the liquid refrigerant separated from the gas refrigerant accumulates at the bottom of the separator 6 and becomes below the liquid level. Through hole 64 of the second inlet/outlet pipe 62 that is immersed
a second inflation mechanism 5 in the second inflation device portion 52 which is led out from the second inlet/outlet pipe 62 via a
6, it reaches the indoor coil 3, and
During heating, the liquid-gas mixed refrigerant, which has been reduced to an intermediate pressure through the two expansion mechanisms 56 and 57 in the second expansion device section 52, flows from the second inlet/outlet pipe 62 through the through hole 64 of the second inlet/outlet pipe 61. The refrigerant is introduced into the separator 6 through the separator 6, and the separator 6 separates the gas refrigerant and liquid refrigerant, and the separated liquid refrigerant accumulates at the bottom of the separator 6 and is immersed below the liquid level. The first inlet/outlet pipe 61 is led out from the first inlet/outlet pipe 61 through the through hole 63 of the first inlet/outlet pipe 61 .
It reaches the outdoor coil 4 via the first expansion mechanism 53 in the expansion device section 51. In the above operation, the first or second inlet/outlet pipe 61, which serves as an inlet pipe for the separator 6,
The liquid-gas mixed refrigerant introduced from 62 tries to be introduced into the separator 6 through the through holes 63 and 64 submerged below the liquid surface of the separator 6, but the stored liquid refrigerant acts as resistance. Since the liquid is introduced through the through holes 63 and 64 that open in the gas region, the liquid level is not disturbed. In addition, in the gas-liquid separator 6, as described above, by using the configuration in which the amount of refrigerant is adjusted by changing the liquid level heights h ₁ and h ₂ during cooling and heating, liquid refrigerant is supplied to the injection tube 9 during cooling. The liquid-gas mixed refrigerant can be injected into the compressor 1. In this case, as shown in FIG. 2, the liquid refrigerant separated and stored in the separator 6 at the tip of the injection tube 9 disposed at the upper part of the separator 6 has a liquid level h ₂ or less, and curve the tip upward to meet the liquid level height h ₂
A through hole 91 is provided in the tube 9 which is opened at a higher position and located below the liquid level height _h2 , and the liquid refrigerant is introduced through the through hole 91. By doing so, during cooling, liquid refrigerant can be injected into the compressor 1 together with gas refrigerant without using a special liquid injection tube. can be cooled. (Effects of the Invention) As described above, the present invention provides the partial liquid separator 6 with the first inlet/outlet pipe 61 communicating with the heat exchanger 4 on the heat source side and the second inlet/outlet pipe 62 communicating with the heat exchanger 5 on the user side. are disposed upward from the bottom of the separator 6, the piping structure of the expansion device 5 can be simplified, and the refrigerant circulation path can be switched so that the circulation direction is reversed during cooling and heating. This allows the number of check valves to be reduced to a minimum of two. Therefore, costs can be reduced, failures can be reduced, and maintenance and inspection efforts can be reduced. Moreover, the first and second inlet/outlet pipes 61, 62
is provided with a plurality of through holes 63 and 64 that open into the interior of the separator 6, so that each of the inlet and outlet pipes 6
Even if 1 and 62 serve as inlet pipes or outlet pipes during cooling and heating, gas-liquid separation can always be performed reliably in the separator 6, and its separation performance can be improved. The liquid refrigerant can be reliably discharged while the level of the liquid refrigerant separated and stored in the separator 6 is maintained at an appropriate level. Moreover, the first and second inlet/outlet pipes 61, 62
Among them, the lowest position of the through hole 63 in the first inlet/outlet pipe 61 which becomes the inlet pipe during cooling and the outlet pipe during heating is the through hole 64 in the second inlet/outlet pipe 62 which becomes the outlet pipe during cooling and becomes the inlet pipe during heating. The lowest position of the gas-liquid separator 6 is set as the upper position, and the level of the liquid separated and stored in the separator 6 is higher during cooling than during heating, thereby providing the gas-liquid separator 6 itself with a refrigerant amount adjustment function. As a result, the amount of refrigerant circulated during heating and cooling can be easily optimized without the need to use a charge modulator as in the past and without increasing costs.

[Brief explanation of drawings]

Fig. 1 is a refrigerant piping system diagram showing one embodiment of the present invention, Fig. 2 is an enlarged schematic cross-sectional view of only the gas-liquid separator, Fig. 3 is a Mollier diagram, and Fig. 4 is the previously proposed refrigeration system. It is a refrigerant piping system diagram showing an example of a device. 1...Compressor, 3...Using side heat exchanger (indoor coil), 4...Heat source side heat exchanger (outdoor coil), 5
... Expansion device, 6 ... Gas-liquid separator, 9 ... Injection tube, 61 ... First inlet/outlet pipe, 6
2...Second entrance/exit pipe, 63, 64...Through hole.

Claims (1)

[Claims] 1. A heat exchanger 4 on the heat source side and a heat exchanger 3 on the user side, with an expansion device 5 and a gas-liquid separator 6 interposed in the middle of the refrigerant piping connecting these heat exchangers 3 and 4. The heat pump is configured such that the intermediate-pressure refrigerant in the expansion process is injected into the compressor 1 from the gas region of the separator 6 through the injection tube 9, and the refrigerant circulation direction is reverse cycle to enable heating and cooling. In the type refrigeration system, the gas-liquid separator 6 includes:
A first inlet/outlet pipe 6 communicating with the heat source side heat exchanger 4
1 and a second inlet/outlet pipe 62 communicating with the utilization side heat exchanger 3 are arranged upward from the lower part of the separator 6, and these inlet/outlet pipes 61, 62
A plurality of through holes 63 and 64 are provided that open into the interior of the separator 6, while the inlet and outlet pipes 61,
62, the lowest position of the through hole 63 in the first inlet/outlet pipe 61, which becomes the inlet pipe during cooling and the outlet pipe during heating, is penetrated in the second inlet/outlet pipe 62, which becomes the outlet pipe during cooling and becomes the inlet pipe during heating. A heat pump type refrigeration system characterized in that the lowest position of the hole 64 is set as the upper position, and the liquid level of the liquid refrigerant separated and stored in the gas-liquid separator 6 is higher during cooling than during heating. 2. An injection tube 9 is provided in the upper part of the gas-liquid separator 6, and the tip of the injection tube 9 is used to control the liquid level of the liquid refrigerant separated and stored in the gas-liquid separator 6 during cooling. The refrigerant refrigerant is extended to a height below the liquid level, and its tip is opened at a position higher than the liquid level, so that the liquid-gas mixed refrigerant is injected from the injection exit tube 9 to the compressor 1 during cooling. A heat pump type refrigeration device according to scope 1.