JP2006132427A - Compressor for hot-water supply and hot-water supply cycle device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a compressor for hot-water supply free from reliability lowering caused by discharge gas of high temperature passing through an electric element section in hot-water supply operation at low outside temperature. <P>SOLUTION: The compressor 10 for hot-water supply comprises an inlet pipe 4 for directly introducing refrigerant of low pressure side to the compression element 2, a discharge pipe 5 for directly discharging high-pressure refrigerant compressed by the compression element 2 outside of a closed container 1 without discharging it into the closed container 1, a refrigerant re-introduction pipe 6 for introducing the refrigerant after heat exchange discharged from the discharge pipe 5 into the closed container 1 again and a refrigerant re-discharge pipe 7 for discharging the refrigerant passed through the electric element 3 outside of the closed container 1. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a hot water supply compressor using a supercritical refrigerant such as carbon dioxide gas and a hot water supply cycle apparatus using the compressor.

In a conventional compressor using carbon dioxide gas refrigerant, in a high-pressure shell type compressor, there is basically only one discharge pipe, and the refrigerant compressed by the compression element is once discharged into the sealed container and then the electric element. The refrigerant gas flow path configuration reaches the discharge pipe through the section (see, for example, Patent Document 1).
Further, a compressor using a carbon dioxide gas refrigerant other than the high pressure shell type is shown as an intermediate pressure shell two-stage compression type compressor. This is because the low-pressure refrigerant gas sucked from the refrigerant introduction pipe to the low-pressure chamber side of the lower cylinder is compressed to an intermediate pressure, discharged into the sealed container, and sucked from the refrigerant introduction pipe to the low-pressure chamber side of the upper cylinder, The refrigerant gas is compressed into high-temperature and high-pressure refrigerant gas and flows into the external gas cooler from the refrigerant discharge pipe (see, for example, Patent Document 2).
In addition, a conventional hot water supply cycle device is generally configured by a compressor, a gas cooler, an expansion valve, and an evaporator, but the configuration of the gas cooler is configured to exchange heat by flowing a refrigerant and water in a counterflow. Become. (For example, refer nonpatent literature 1).
Moreover, as the form which divides | segments a gas cooler, the example divided | segmented into the heat exchange part of a refrigerant | coolant-water and the heat exchange part of refrigeration oil-water is shown. (For example, refer to Patent Document 3).

JP 2003-262192 (pages 4 to 6, FIG. 1) JP-A-2004-156539 (pages 4 to 6, FIG. 1) “Non-Freon Technology” Ohm, February 1, 2004, p. 40, Fig. 3.1.1 JP 2001-304701 (2nd page, 3rd page, FIG. 1)

  First, problems in using a conventional high-pressure shell type compressor in a conventional hot water supply cycle apparatus will be described. In the case of a high-pressure shell type compressor, it is necessary to maintain a sealing property in the compression element by mixing an appropriate amount of refrigeration oil in the compression chamber when the refrigerant is compressed by the compression element. The mixture of refrigerant and refrigerating machine oil compressed in the compression element is once discharged into the sealed container, and after passing through the electric element part, the refrigerant and refrigerating machine oil are separated until reaching the discharge pipe, Refrigerant gas which is hardly contained is discharged from the discharge pipe. Further, when the refrigerant gas passes through the electric element portion, the electric element portion is cooled by heat generated in the electric element portion moving to the refrigerant gas.

In the normal temperature range, the above operation has the effect of preventing refrigerating machine oil from being discharged into the refrigerant cycle and preventing the temperature of the electric element from rising. In hot water supply applications, it is necessary to boil water up to a predetermined temperature. Therefore, it must be raised to a predetermined discharge temperature in terms of function.
FIG. 9 shows, for example, an ideal gas cooler (gas cooler outlet temperature = feed water temperature, pinch point temperature difference = 0 ° C.), an ideal evaporator (evaporation temperature = outside air temperature, intake SH = 5 deg) and a compressor with a heat insulation efficiency of 60%. The calculated value of the discharge temperature required for boiling water with a feed water temperature of 5 ° C. up to 90 ° C. is shown. It can be seen from the figure that the lower the outside air temperature, the lower the discharge pressure and the higher the discharge temperature. For example, when the outside air temperature is −20 ° C., the discharge gas temperature is 145 ° C.

  In general, the normal usable limit temperature of materials such as PET used for motor insulation is about 120 ° C to 130 ° C, and other resin materials exceed the temperature in the vicinity of this. There is a problem such as extraction, and passing hot discharge gas to the motor section impairs the reliability of the compressor and refrigerant cycle, so it is difficult to perform hot water supply operation at low outside temperatures where the discharge gas becomes hot There was a problem.

  Regarding the above problem, it is possible to keep the discharge temperature low by reducing the amount of water to be exchanged with respect to the refrigerant flow rate, but this is because of the efficiency of the hot water supply cycle device and the hot water supply per unit refrigerant flow rate. There was a problem that it would be difficult to obtain predetermined efficiency and hot water supply capacity because the capacity would be greatly reduced.

  Next, a case where a conventional intermediate pressure shell two-stage compression type is used in a conventional hot water supply cycle apparatus as a compressor other than the high pressure shell type will be described. In the intermediate pressure shell two-stage compression type, the compression work is performed in two stages of the first compression element and the second compression element, and the discharge gas from the first compression element is released into the sealed container. The temperature becomes the intermediate discharge temperature, and the refrigerant gas compressed by the second compression element, which becomes high temperature, is discharged directly from the second compression element to the outside of the sealed container. The above-mentioned reliability problem can be avoided.

  However, even in the case of the intermediate pressure two-stage compression type, when compressing the refrigerant, an appropriate amount of refrigerating machine oil is mixed in the compression chamber to maintain the sealing performance in the compression element, and is compressed in the compression element. The mixture of the refrigerant and the refrigerating machine oil is discharged out of the sealed container without passing through the oil separation means. When a large amount of refrigeration oil is discharged into the refrigerant circuit, the heat exchange performance in the gas cooler or evaporator decreases, the pressure loss in the piping increases, the discharge temperature decreases due to the transfer of refrigerant gas heat to the refrigeration oil, There are problems such as a decrease in water heating capacity due to the specific heat difference between the refrigerant and the refrigerating machine oil in the gas cooler, and there is a problem that sufficient hot water supply performance is difficult to obtain.

The present invention has been made to solve the above-described problem, and has a hot water supply compressor that does not have a decrease in reliability due to high-temperature discharge gas passing through an electric element when a hot water supply operation is performed at a low outside air temperature. The purpose is to obtain.
Also, by circulating a large amount of refrigerating machine oil in the hot water supply cycle device, the heat exchange performance in the gas cooler and evaporator decreases, the pressure loss in the piping increases, the discharge temperature due to the heat of the refrigerant gas moving to the refrigerating machine oil It is an object of the present invention to obtain a hot water supply compressor that does not cause problems such as a decrease in water heating capacity due to a decrease in water heating capacity due to a specific heat difference between refrigerant and refrigeration oil in a gas cooler.
It is another object of the present invention to provide a hot water supply compressor that can improve the heat exchange efficiency between water and refrigerant in a gas cooler and improve hot water supply performance.
Another object of the present invention is to obtain a hot water supply cycle apparatus having a gas cooler with high reliability and high heat exchange efficiency and / or no large amount of circulating oil by using such a hot water supply compressor.

The present invention relates to a hot water supply compressor that has a compression element and an electric element in a hermetic container, uses a supercritical refrigerant as a refrigerant, and is used for hot water supply, and is a suction pipe that directly leads a low-pressure side refrigerant to the compression element And a discharge pipe that directly discharges the high-pressure refrigerant compressed by the compression element to the outside of the sealed container without releasing it into the sealed container, and a refrigerant that is discharged from the discharge pipe and guides the refrigerant after heat exchange into the sealed container again. A hot water supply compressor provided with a reintroduction pipe and a refrigerant redischarge pipe that reintroduces the refrigerant into the sealed container and discharges the refrigerant after passing through the electric element to the outside of the sealed container.
Further, the hot water supply cycle apparatus having the above hot water supply compressor is configured such that a water pipe through which water for hot water supply circulates and a refrigerant pipe through which compressed refrigerant circulates in the gas cooler, and the water pipe is supplied by the refrigerant of the refrigerant pipe. Among the refrigerant pipes, the high-temperature side refrigerant pipe connected to the discharge pipe exchanges heat with the outlet side of the water pipe of the gas cooler, and the low-temperature side refrigerant connected to the refrigerant re-discharge pipe The pipe exchanges heat with the inlet side of the water pipe of the gas cooler.

The compressor for hot water supply of the present invention discharges the high-pressure refrigerant compressed by the compression element by the discharge pipe directly to the outside of the sealed container without releasing it into the sealed container, and reintroduces the refrigerant after exchanging heat outside the hot water compressor. Since the pipe is reintroduced into the sealed container and passes through the electric element, it is discharged out of the compressor for hot water supply from the refrigerant re-discharge pipe, so even if the compressed refrigerant temperature is high at low outside temperatures, Since it is the refrigerant gas whose temperature has decreased after heat exchange outside the hot water supply compressor that does not pass through the element, the reliability of the electric element can be prevented from decreasing.
Further, the hot water supply compressor of the present invention has an effect of cooling the electric element because the refrigerant gas whose temperature has decreased after heat exchange outside the hot water supply compressor passes through the electric element.
Further, in the hot water supply cycle apparatus having the hot water supply compressor of the present invention, the refrigerant gas is reintroduced into the sealed container by the refrigerant reintroduction pipe of the hot water supply compressor, and is discharged from the refrigerant redischarge pipe after passing through the electric element. However, since heat is exchanged with the inlet side of the water pipe of the gas cooler by the low-temperature side refrigerant pipe, the refrigeration oil is separated when passing through the electric element, and the refrigeration oil that goes out to the pipe after the refrigerant re-discharge pipe is reduced. It is possible to prevent a decrease in heat exchange in the vessel and an increase in pressure loss in the piping.
Further, in the hot water supply cycle apparatus having the hot water supply compressor of the present invention, the high temperature side refrigerant pipe connected to the discharge pipe of the hot water supply compressor exchanges heat with the outlet side of the water pipe of the gas cooler inside the gas cooler. The low temperature side refrigerant pipe exchanges heat with the inlet side of the water pipe of the gas cooler. The high-temperature side refrigerant piping contains a large amount of refrigeration oil, but the refrigerant gas is hot, the specific heat is not so large, and the difference in specific heat between the refrigerant gas and the refrigeration oil is small, so there is almost no effect on the heat exchange performance. The gas cooler has sufficient heat exchange performance.

Embodiment 1 FIG.
1 is a cross-sectional view of a high-pressure shell type hot water supply compressor according to Embodiment 1 of the present invention, and FIG. 2 is a configuration diagram of a hot water supply cycle apparatus using the hot water supply compressor of FIG.
In the figure, reference numeral 10 denotes a hot water supply compressor using a supercritical refrigerant such as carbon dioxide. The compressor for hot water supply accommodates in a hermetic container 1 a compression element 2 for compressing refrigerant at the lower part, an electric element 3 composed of a rotor 3a and a stator 3b at the upper part, and an oil sump 8 for storing refrigerator oil at the bottom part. To do. The compression element 2 compresses the refrigerant by the rotation of the rotating shaft by the electric element 3.
Further, the sealed container 1 includes a suction pipe 2 that takes in the refrigerant on the low-pressure side of the refrigeration cycle into the compression element 2, a discharge pipe 5 that discharges the refrigerant compressed by the compression element 2 to a gas cooler 20 described later outside the hot water compressor, and a gas cooler. A refrigerant reintroduction pipe 6 that reintroduces the refrigerant from 20 and a refrigerant redischarge pipe 7 that redischarges the refrigerant to the gas cooler 20 are attached.
The gas cooler 20 is composed of a water pipe 70, a high-temperature side refrigerant pipe 80 (to be described later) and a low-temperature side refrigerant pipe 90 (to be described later) for exchanging heat with the water in the water pipe 70.

The high temperature side refrigerant pipe 80 is a pipe connected to the discharge pipe 5 and the refrigerant reintroduction pipe 6, and the refrigerant in the pipe exchanges heat with water on the high temperature side of the water pipe 70 of the gas cooler 20, The low temperature side refrigerant pipe 90 is a pipe connected to the refrigerant redischarge pipe 7 and the expansion valve 30. Similarly, the refrigerant in the pipe exchanges heat with the low temperature side water of the water pipe 70 of the gas cooler 20 in the gas cooler 20.
And the hot water supply compressor 10, the gas cooler 20, the expansion valve 30, and the evaporator 40 are connected with piping, and the hot water supply cycle apparatus is comprised.

Next, the operation will be described.
In the hot water supply cycle apparatus configured as described above, first, a low-pressure refrigerant gas is introduced into the compression element 2 from the suction pipe 4 of the compressor 10, and the compression element 2 is compressed by the driving force generated by the electric element 3. I do. At that time, the refrigerating machine oil is sucked up from the oil reservoir 8 and supplied into the compression element 2 to maintain the sealing performance in the compression element 2 and to obtain a predetermined compressor performance. The resulting mixture of high-pressure refrigerant gas and refrigerating machine oil is discharged out of the sealed container 1 through the discharge pipe 5.

  The mixture of the high-pressure refrigerant gas and the refrigerating machine oil discharged from the discharge pipe 5 enters the gas cooler 20 through the high temperature side refrigerant pipe 80. In the gas cooler 20, heat exchange is performed between the mixture of high-pressure refrigerant gas and refrigerating machine oil in the high-temperature side refrigerant pipe 80 and the water in the high-temperature side water pipe 20, and the water temperature in the water pipe 20 increases. Then, the mixture of the high-pressure refrigerant gas and the refrigerating machine oil in the high temperature side refrigerant pipe 80 is cooled. The cooled mixture of high-pressure refrigerant gas and refrigerating machine oil after the heat exchange is reintroduced between the compression element 2 and the electric element 3 in the hermetic container 1 of the hot water supply compressor 10 through the refrigerant reintroduction pipe 6.

  The mixture of the high-pressure refrigerant gas and the refrigerating machine oil reintroduced in the sealed container 1 passes through the electric element 3 in the sealed container 1 and reaches the refrigerant re-discharge pipe 7 disposed on the upper part of the sealed container 1. . At this time, it is included in the mixture of the high-pressure refrigerant gas and the chiller oil by an oil separation mechanism, which will be described later, mainly composed of the electric element 3 until it passes through the electric element 3 and reaches the refrigerant re-discharge pipe 7. The refrigerating machine oil thus separated is separated, and the refrigerant re-discharge pipe 7 reaches the high-pressure refrigerant gas that hardly contains the refrigerating machine oil. Further, the heat generated in the electric element 3 when passing through the electric element 3 moves to the refrigerant gas, the temperature of the refrigerant gas rises, and the electric element 3 has a cooling effect and has a large temperature. Prevent the rise. The high-pressure refrigerant gas that contains almost no refrigeration oil reaching the refrigerant re-discharge pipe 7 is discharged from the refrigerant re-discharge pipe 7 to the outside of the sealed container 1.

  The high-pressure refrigerant gas discharged from the refrigerant re-discharge pipe 7 to the outside of the sealed container 1 enters the low-temperature side of the gas cooler 20 through the low-temperature side refrigerant pipe 90, and the high-pressure refrigerant gas and the low-temperature side water in the low-temperature side refrigerant pipe 90. Heat is exchanged with the water in the pipe 70, the water temperature in the low temperature side water pipe 70 rises and flows into the high temperature side water pipe 70, and the high pressure refrigerant gas in the low temperature side refrigerant pipe 90 is cooled. . The high-pressure refrigerant gas sufficiently cooled in the low-temperature side refrigerant pipe 90 passes through the expansion valve 30 and the evaporator 40 and is sucked into the hot water supply compression element 10 from the suction pipe 4 of the hot water supply compressor 10 as a low pressure refrigerant gas. The

The oil separation during the above operation will be described.
Generally, on the lower side of the electric element 3, there is a refrigerant gas containing a large amount of refrigerating machine oil, which is a gap between the rotor 3a and the stator 3b constituting the electric element 3 and the upper and lower parts formed in the rotor 3a. The refrigerant gas on the lower side of the electric element 3 rises to the upper side of the electric element 3 through a hole (not shown) communicating in the direction, and the refrigerating machine oil is fixed on the outside by the centrifugal force accompanying the rotation of the rotor 3a. Refrigerant gas containing almost no refrigerating machine oil reaches the refrigerant re-discharge pipe 7 separated by being blown in the direction of the child 3b and opened near the rotation center of the rotor 3a. Further, the refrigerating machine oil separated above the electric element 3 returns to the lower side of the electric element 3 through the gap between the outer periphery of the stator 3 b and the sealed container 1. Therefore, as shown in FIG. 1, the opening of the refrigerant re-introducing pipe 6 in the sealed container 1 is set inside the outer diameter of the rotor 3 a between the compression element 2 and the electric element 3. The refrigerant flow passing from the lower side to the upper side of the electric element 3 through the outer periphery of the electric element 3b decreases, and the function of the separated refrigeration oil returning from the outer periphery of the stator 3b to the lower part of the electric element 3 is enhanced. Oil separation operation can be performed reliably.

The oil separation capability is related to the density difference between the refrigeration oil and the refrigerant. The density of the refrigerating machine oil is generally about 800 to 1000 kg / m ³ , and the density of the refrigerant on the high pressure side varies greatly depending on the temperature, and is about 100 to 1000 kg / m ³ . When the refrigerant gas is high temperature, the density is small, and when the refrigerant gas is low temperature, the density is large and close to a liquid. In a conventional hot water supply compressor, the refrigerant gas on the high-pressure side that performs oil separation is sufficiently high because it is immediately after being discharged from the compression element 2, and the density of the refrigerant is small, so that the refrigerant and the refrigerating machine oil are separated. Although advantageous, in the configuration of the present invention, the high-pressure refrigerant gas discharged from the compression element 2 is cooled in the high-temperature side refrigerant pipe 80 of the gas cooler 20, so that in order to ensure oil separation capability, It is necessary to limit the temperature of the refrigerant gas on the high pressure side that returns to the refrigerant reintroduction pipe 6 through the high temperature side refrigerant pipe 80 of the gas cooler 20.

  FIG. 3 shows experimental values of the relationship between the density ratio (refrigerant density / oil density) between refrigerant gas and refrigerating machine oil, and the amount of oil circulation. FIG. 3 shows that when the density ratio between the refrigerant gas and the refrigerating machine oil is approximately 0.5 or more, the amount of oil circulation tends to increase significantly. Therefore, the temperature of the high-pressure refrigerant gas that returns to the refrigerant reintroduction pipe 6 through the high temperature side refrigerant pipe 80 of the gas cooler 20 needs to be limited so that the density ratio is 0.5 or less.

As described above, the high temperature side refrigerant pipe 80 in the gas cooler 20 contains a large amount of refrigerating machine oil in the refrigerant gas. In the gas cooler 20, high-temperature refrigeration oil also exchanges heat with water. However, if the specific heat of the refrigeration oil becomes smaller than the specific heat of the refrigerant gas, there is a concern about a decrease in heating capacity and a resulting decrease in hot water supply efficiency. .
FIG. 4 shows the relationship between the temperature and specific heat of refrigerant gas and refrigeration oil. As shown in FIG. 4, it can be seen that the specific heat of the refrigerant gas significantly increases when the temperature is between 20 ° C. and 60 ° C. In order to prevent a decrease in heating capacity due to a large amount of refrigeration oil contained in the refrigerant gas, it is necessary to make the refrigerant gas contain almost no refrigeration oil in a temperature range where the specific heat of the refrigerant gas greatly increases. is there.
FIG. 5 shows the heat exchange of refrigerant gas and water on the TH diagram. As shown in FIG. 5, the upper limit temperature in the range in which the specific heat of the refrigerant gas suddenly rises is a temperature obtained by adding 10 ° C. to the pinch point temperature at which the refrigerant gas and water temperatures reapproach. That is, if the outlet temperature of the high temperature side refrigerant pipe 80 of the gas cooler 20 (≈refrigerant reintroduction pipe temperature) is 10 ° C. or more higher than the pinch point temperature, it is possible to prevent a reduction in heating capacity. If the temperature is at least higher than the pinch point temperature, it is possible to prevent a significant decrease in heating capacity.

  In the hot water supply compressor of the present embodiment, the high-temperature refrigerant gas discharged from the compression element 2 is discharged from the discharge pipe 5 to the outside of the sealed container 1, and the water pipe 70 is connected to the high-temperature side refrigerant pipe 80 in the gas cooler 20. The refrigerant gas passing through the electric element 3 of the hot water supply compressor 10 was discharged from the compression element 2 because the refrigerant re-introduced pipe 6 enters the sealed container 1 after being cooled by heat exchange with water. Since the temperature is lower than the temperature, the refrigerant gas temperature in the electric element 3 is low even when the discharge gas temperature from the compression element 2 is high in the operation of the low outside air temperature, and the electric element 3 is thermally damaged. Therefore, there is an effect that an operation with a high discharge temperature of the hot water supply compressor 10 can be realized even at a low outside air temperature.

  In the hot water supply compressor according to the present embodiment, the refrigerant reintroducing pipe 6 is disposed between the compression element 2 and the electric element 3 so that the oil is separated by a general oil separation method around the electric element 3. There is an effect that can be.

  In addition, the hot water supply compressor of the present embodiment has an effect that the oil separation operation can be reliably performed because the refrigerant reintroduction pipe 6 is opened inside the outer diameter of the rotor 3a.

  Further, the hot water supply cycle apparatus of the present embodiment is configured so that the refrigerant gas density in the refrigerant reintroduction pipe 6 (the outlet of the gas cooler 20 toward the refrigerant reintroduction pipe 6) is 50% or less of the oil density, whereby the hot water supply compressor 10 is used. In this case, the oil separation ability can be secured.

  In the hot water supply cycle apparatus of the present embodiment, the refrigerant gas temperature in the refrigerant reintroduction pipe 6 is set to the pinch point temperature or more, whereby the refrigerant gas containing a large amount of refrigeration oil is supplied to the high temperature side refrigerant pipe 80 of the gas cooler 20. Even if it flows, there is almost no decrease in the heating capacity for heating the water in the water pipe 70, and there is an effect that good performance can be maintained.

  In the hot water supply cycle apparatus of the present embodiment, the refrigerant reintroduction pipe 6 is disposed between the compression element 2 and the electric element 3, so that the refrigerant gas reintroduced into the sealed container 1 Since it passes through and reaches the refrigerant re-discharge pipe 7, the heat generated in the electric element 3 moves to the refrigerant gas and has an effect of cooling the electric element 3.

Embodiment 2. FIG.
FIG. 6 shows the configuration of the refrigerant circuit showing the second embodiment of the present invention. In the first embodiment, in the gas cooler 20, the low temperature side refrigerant pipe 90 and the high temperature side refrigerant pipe 80 are configured to exchange heat with the low temperature side water pipe 70 and the high temperature side water pipe 70 without wrapping each other. However, in the present embodiment, an example in which a part of the low temperature side refrigerant pipe 90 and the high temperature side refrigerant pipe 80 are wrapped is shown. In the present embodiment, the low temperature side refrigerant pipe 90 is wrapped with a part of the high temperature side refrigerant pipe 80, but may be wrapped with the entire area of the high temperature side refrigerant pipe 80. Further, a refrigerant-refrigerant heat exchanger 50 for exchanging heat between the two refrigerants is arranged in the vicinity of the discharge pipe 5 and the refrigerant reintroduction pipe 6, and the refrigerant discharge temperature of the discharge pipe 5 and the refrigerant discharge temperature of the refrigerant redischarge pipe 7 are set. The difference is reduced. Note that this configuration is established even without the refrigerant-refrigerant heat exchanger 50. Further, the refrigerant-refrigerant heat exchanger 50 may exchange heat between the discharge pipe 5 and the refrigerant re-discharge pipe 7. Other configurations are the same as those in the first embodiment.

FIG. 7 is a TH diagram for explaining that the high-temperature side refrigerant pipe 80 and the low-temperature side refrigerant pipe 90 wrap in the gas cooler 20 and each refrigerant exchanges heat with the water in the water pipe 70. FIG. 7A shows a case where the high temperature side refrigerant pipe 80 and the low temperature side refrigerant pipe 90 do not wrap, and FIG. 7B shows a case where the high temperature side refrigerant pipe 80 and the low temperature side refrigerant pipe 90 wrap. For the sake of simplicity, it is assumed in this embodiment that the temperature of the high temperature side refrigerant pipe 80 and the low temperature side refrigerant pipe 90 of the gas cooler 20 are equal due to the effect of the refrigerant-refrigerant heat exchanger 50. explain.
In general, the heat exchange efficiency of refrigerant gas and water is better when the temperature difference between the two is small, but the specific heat changes depending on the temperature of the refrigerant gas and water. Even if it exists, in the part shown to A and B of Fig.7 (a), the difference of refrigerant gas temperature and water temperature will arise, and it will become the tendency for heat exchange efficiency to deteriorate. In FIG. 7 (b), since the high temperature side refrigerant pipe 80 and the low temperature side refrigerant pipe 90 are wrapped in the portion A where the difference between the refrigerant gas temperature and the water temperature is large, the substantial refrigerant flow rate is 2 in this part. The slope of water on the TH diagram is doubled. Thereby, the temperature difference of refrigerant gas and water becomes small, the area of A part decreases, and heat exchange efficiency can be improved. Thereby, the heat exchange efficiency of the gas cooler 20 is improved, and the efficiency of the hot water supply cycle is improved.

  However, in order to implement the above configuration, there is a temperature limitation, and the refrigerant temperature at the inlet of the low temperature side refrigerant pipe 90 needs to be higher than the temperature of the water in the same portion by a predetermined temperature or more. If the refrigerant temperature is lower, heat is transferred from the water to the refrigerant gas, resulting in a loss. In order to actually obtain the effect of wrapping the high temperature side refrigerant pipe 80 and the low temperature side refrigerant pipe 90, the refrigerant gas temperature at the inlet of the low temperature side refrigerant pipe 90 is higher than the temperature of the water in the same portion, for example, boiling water The temperature is higher than the temperature or 5 ° C higher than the temperature of water.

  In order to increase the amount of lap between the low temperature side refrigerant pipe 90 and the high temperature side refrigerant pipe 80, the inlet temperature of the low temperature side refrigerant pipe 90 needs to be increased. Since heat is exchanged between the discharge pipe 5 and the refrigerant reintroduction pipe 6 by the refrigerant-refrigerant heat exchanger 50, the inlet temperature of the low temperature side refrigerant pipe 90 can be increased, and the high temperature side refrigerant pipe 80 and the low temperature side refrigerant pipe 90 can be The wrap amount can be increased and the performance improvement effect can be enhanced.

  In the hot water supply cycle apparatus of the present embodiment, the low temperature side refrigerant pipe 90 in the gas cooler 20 is arranged so as to wrap with part or all of the high temperature side refrigerant pipe 80, so that the heat exchange efficiency with the water pipe 70 is increased. Can do.

  In the hot water supply cycle apparatus of the present embodiment, the refrigerant temperature at the gas cooler 20 inlet of the low temperature side refrigerant pipe 90 is higher than the water temperature of the water pipe 70 for heat exchange with the inlet side of the low temperature side refrigerant pipe by a predetermined temperature or more. Since it did in this way, heat does not move from the water of the water piping 70 to refrigerant gas, and heat loss can be prevented.

  Further, in the hot water supply cycle apparatus of the present embodiment, the refrigerant in the outlet high temperature side refrigerant pipe 80 near the discharge pipe 5 and the inlet side high temperature side refrigerant pipe 80 near the refrigerant reintroduction pipe 6 exchange heat. Since the heat exchange device 50 is provided, the temperature of the refrigerant in the high temperature side refrigerant pipe 8 on the entry side can be increased, and heat loss in the gas cooler 20 can be prevented.

  In the hot water supply cycle apparatus of the present embodiment, the refrigerant in the outlet high temperature side refrigerant pipe 80 near the discharge pipe 5 and the outlet side low temperature refrigerant pipe 90 in the vicinity of the refrigerant redischarge pipe 7 exchange heat. Since the heat exchange device 50 is provided, the temperature of the refrigerant in the outlet-side low-temperature side refrigerant pipe 90 can be increased, and heat loss can be prevented from occurring in the gas cooler 20.

Embodiment 3 of the Invention
In the configuration where the low temperature side refrigerant pipe 90 and the high temperature side refrigerant pipe 80 wrap in the gas cooler 20 shown in the second embodiment of the present invention, the efficiency improvement effect increases as the outside air temperature decreases. There are cases where the temperature of the discharge pipe 5 is close to the boiling temperature of water and a loss is caused by providing a wrap portion.
FIG. 8 shows the configuration of the refrigerant circuit of the third embodiment. In the figure, a bypass pipe 80 a that branches from the middle of the high-pressure side refrigerant pipe 80 in the gas cooler 20 and is connected to the high-pressure side refrigerant pipe 80 toward the refrigerant reintroduction pipe 6 outside the gas cooler 20 is provided. In addition, a switching valve 80b, which is a valve, is arranged at this connection portion so that the bypass pipe 80a can be selectively connected to the refrigerant reintroduction pipe 6 by valve operation. Other configurations are the same as those of the second embodiment.

Next, the operation will be described. When the outside air temperature is high, the discharge temperature does not rise so much, and the difference between the refrigerant temperature in the discharge pipe 5 and the water boiling temperature becomes small, so the outlet of the high temperature side refrigerant pipe 80 selects the bypass pipe 80b, Loss caused by wrapping the high-pressure side pipe 80 and the low-pressure side pipe 90 is prevented.
On the other hand, when the outside air temperature is low, the discharge pressure does not increase, but the discharge temperature tends to increase significantly. Therefore, even if the section of the high temperature side refrigerant pipe 80 is taken longer, the temperature of the outlet side of the high temperature side refrigerant pipe 80 is Above boiling temperature. Therefore, it is better to lengthen the high-pressure side pipe 80, and the effect of improving the efficiency is greater when the refrigerant flows to the end 80a, and the temperature of the refrigerant reintroduction pipe 6 which is the main object of the present invention is reduced. The effect is also increased.

  According to the hot water supply cycle apparatus of the present embodiment, the high temperature side refrigerant pipe 80 branches from the middle in the gas cooler 20 and is connected to the high temperature side refrigerant pipe 80 that returns to the refrigerant reintroduction pipe 6 outside the gas cooler 20. By switching the outlet from the gas cooler 20 by operating the valve, it is possible to select whether or not the low-temperature side refrigerant pipe 90 and the high-temperature side refrigerant pipe 80 are wrapped. With or without switching wraps, the exit from 20 can be selected to prevent heat loss and improve heat exchange efficiency.

It is sectional drawing which shows the structure of the compressor for hot water supply in Embodiment 1 of this invention. It is a figure which shows the structure of the hot water supply cycle which uses the compressor for hot water supply of FIG. It is a figure which shows the relationship between refrigerant gas density / refrigerator oil density, and the amount of oil circulation. It is a figure which shows temperature, the specific heat of refrigerant gas, and the specific heat of refrigeration oil. It is a TH diagram which shows heat exchange of a refrigerant | coolant and water. It is a figure which shows the structure of the hot water supply cycle in Embodiment 2 of this invention. It is a TH diagram which shows heat exchange of the refrigerant | coolant and water in Embodiment 2 of this invention. It is a figure which shows the structure of the hot water supply cycle in Embodiment 3 of this invention. It is a figure which shows the relationship between the external air temperature required in order to boil water temperature from 5 degreeC to 90 degreeC, and discharge temperature.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Airtight container, 2 Compression element, 3 Electric element, 3a Rotor, 4 Intake pipe, 5 Discharge pipe, 6 Refrigerant reintroduction pipe, 7 Refrigerant redischarge pipe, 10 Hot water supply compressor, 20 Gas cooler, 30 Expansion valve, 40 Evaporator, 50 heat exchanger, 70 water piping, 80 high temperature side refrigerant piping, 80a bypass piping, 80b valve, 90 low temperature side refrigerant piping.

Claims (11)

In a hot water compressor having a compression element and an electric element in a sealed container, using a supercritical refrigerant as a refrigerant, and used for hot water supply,
A suction pipe that directly guides the low-pressure side refrigerant to the compression element; a discharge pipe that discharges the high-pressure refrigerant compressed by the compression element directly to the outside of the sealed container without being discharged into the sealed container; and a discharge pipe that discharges from the discharge pipe And a refrigerant reintroduction pipe for reintroducing the heat-exchanged refrigerant into the sealed container and a refrigerant re-discharge for re-introducing the refrigerant into the sealed container and discharging the refrigerant after passing through the electric element to the outside of the sealed container. A hot water compressor comprising a pipe.   The compression element is disposed on the lower side of the electric element, and the refrigerant reintroduction pipe is attached to the sealed container so as to be between the compression element and the electric element in the height direction. The hot water supply compressor according to claim 1.   The hot water supply compressor according to claim 2, wherein the refrigerant reintroduction pipe is opened to an inner side than an outer diameter of a rotor constituting the electric element. A hot water supply cycle apparatus comprising the hot water supply compressor according to any one of claims 1 to 3, a gas cooler, an expansion valve, an evaporator, and the like.
In the gas cooler, heat is exchanged between a water pipe through which hot water is circulated and a refrigerant pipe through which a compressed refrigerant circulates, and the temperature of the water pipe is increased by the refrigerant in the refrigerant pipe. ,
Among the refrigerant pipes, a high-temperature side refrigerant pipe connected to the discharge pipe exchanges heat with an outlet side of the water pipe of the gas cooler, and a low-temperature side refrigerant pipe connected to the refrigerant re-discharge pipe is the A hot water supply cycle device that exchanges heat with an inlet side of a water pipe.   The hot water supply cycle apparatus according to claim 4, wherein a refrigerant density at the gas cooler outlet of the high-temperature side refrigerant pipe is 50% or less of a refrigerating machine oil density of the refrigerating machine oil circulating along with the refrigerant.   The hot water supply cycle apparatus according to claim 4, wherein the refrigerant temperature at the gas cooler outlet of the high temperature side refrigerant pipe is higher than a refrigerant temperature at a pinch point.   The hot water supply cycle apparatus according to any one of claims 4 to 6, wherein the low temperature side refrigerant pipe of the gas cooler is arranged to wrap with a part or all of the high temperature side refrigerant pipe.   The high temperature side refrigerant pipe has a bypass pipe that branches from the middle in the gas cooler and connects to the high temperature side refrigerant pipe that returns to the refrigerant reintroduction pipe outside the gas cooler, and an outlet from the gas cooler is operated by a valve operation. The hot water supply cycle apparatus according to claim 7, wherein it is possible to select the presence or absence of a lap arrangement between the low temperature side refrigerant pipe and the high temperature side refrigerant pipe by switching.   The refrigerant temperature at the gas cooler inlet of the low-temperature side refrigerant pipe is higher than a water temperature of a water pipe for heat exchange with the low-temperature side refrigerant pipe at the inlet side by a predetermined temperature or more. The hot water cycle apparatus described.   8. The heat exchange device according to claim 7, wherein the refrigerant exchanges heat between the high temperature side refrigerant pipe near the discharge pipe and the high temperature side refrigerant pipe near the refrigerant reintroduction pipe. The hot water supply cycle apparatus according to any one of claims 9 to 9. 8. A heat exchanging device for exchanging heat between the refrigerant in the high-temperature side refrigerant pipe near the discharge pipe and the low-temperature side refrigerant pipe near the refrigerant re-discharge pipe. The hot water supply cycle apparatus according to claim 9.

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