JP2006105458A - Refrigerant circulation system and hermetic compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigerant circulation system using a heat pump cycle capable of reducing the temperature of discharged refrigerant gas to a temperature not causing troubles in an electric motor or lubricating oil without deteriorating the heating capability to a heating fluid even in application of a high-pressure shell-type hermetic compressor to the refrigerant circulation system. <P>SOLUTION: This system comprises the heat pump cycle, a radiator heating the heating fluid by heat exchange with high-temperature refrigerant, the high-pressure shell-type hermetic compressor, an oil basin for storing lubricating oil formed within a sealed container, and a lubricating oil circulating passage extending from the oil basin to the radiator and then returning to a suction side that is an inlet of the hermetic compressor through a restriction mechanism. The lubricating oil in the oil basin is circulated to the lubricating oil circulating circuit by a pressure difference between high pressure and low pressure, and then guided to the radiator, in which the lubricating oil is cooled by heat exchange with the heating fluid together with a refrigerant. The lubricating oil is then reduced in pressure by the restriction mechanism, and supplied to the suction side that is the inlet of the hermetic compressor. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a refrigerant circulation device using a heat pump cycle used for hot water supply and the like, and a hermetic compressor used in the refrigerant circulation device.

In recent years, a hot water supply refrigerant circulation device that heats water, which is a heating fluid, to a predetermined temperature using a heat pump cycle that uses a supercritical refrigerant whose high-pressure side pressure such as CO ₂ exceeds a critical point as a refrigerant has been commercialized. . As one of the components of this heat pump cycle, there is a hermetic compressor that compresses a refrigerant to high temperature and high pressure. The bottom of the hermetic container of this compressor is lubricated to lubricate the sliding part of the compressor. Oil is stored, pumping up the lubricating oil at the bottom of the sealed container using a pump or pressure difference, and through the oil holes provided in the axial direction on the drive shaft of the compressor, Lubricating oil is supplied to the sliding part. The lubricating oil is usually returned again to the oil sump inside the sealed container after the sliding portion has been lubricated. When CO ₂ is used as the refrigerant, the difference between the discharge pressure and the suction pressure of the compressor, the so-called high / low pressure difference is very large, so that the lubricating oil is supplied to the inside of the compression chamber to improve the sealing performance of the compression chamber 24. In some cases, measures are taken to prevent a reduction in efficiency due to refrigerant leakage from the high pressure side to the low pressure side in the compression chamber.

  When supplying the lubricating oil to the compression chamber 24, the supplied lubricating oil is discharged together with the discharged refrigerant gas from the compression chamber 24 together with the compressed refrigerant. If the lubricating oil cannot be separated from the refrigerant and the inside of the compressor, the discharge is performed. Together with the refrigerant gas, it flows out from the discharge pipe of the compressor to the piping of the heat pump cycle connected to this discharge pipe, and circulates the cycle. Generally speaking, this is called compressor oil rise. However, if the amount of lubricating oil circulation in the cycle increases due to this compressor oil rise, the heat exchange efficiency in the radiator and evaporator will decrease, resulting in a decrease in heat pump cycle efficiency. Will occur.

  Further, if the amount of lubricating oil circulating in the cycle increases, the amount of lubricating oil inside the compressor decreases, and in the worst case, there is a problem that the lubricating oil inside the compressor is depleted. In such a state, the lubricating oil is not supplied to the sliding portion inside the compressor, and abnormal wear occurs on the sliding portion due to poor lubrication, or seizure occurs and locks, and the compressor cannot be operated. Connected.

  In the case of a low-pressure shell type compressor with a suction pressure atmosphere inside the compressor, the oil sump and the motor that drives the main shaft of the compressor are in the suction pressure atmosphere, and the temperature of the lubricating oil and the motor is not exposed to high-temperature refrigerant However, the total amount of lubricating oil supplied to the inside of the compression chamber flows out to the cycle outside the compressor together with the refrigerant gas whose pressure has been increased to the discharge pressure. It becomes very large and tends to lead to exhaustion of lubricating oil inside the compressor.

  Therefore, an oil separator is installed on the high-pressure side located downstream of the compressor in the cycle. The oil separator separates the lubricating oil contained in the discharge gas, and the separated lubricating oil is removed from the pressure difference by a capillary tube. Then, the pressure is reduced and sent to the low pressure side, and supplied again together with the refrigerant suction gas to the inside of the compressor and returned to the oil sump at the bottom of the compressor to prevent depletion of the lubricating oil (for example, Patent Document 1 and Patent Document 2). reference).

However, the installation of this oil separator increases the number of parts, which naturally increases the cost of the system. Therefore, when designing a system using a CO ₂ refrigerant, there is a demand to use a compressor that can perform oil separation inside the compressor even if a large amount of lubricating oil is supplied to the inside of the compression chamber, and can suppress oil rising. Therefore, the inventors have proposed the use of a high-pressure shell-type hermetic compressor in which the inside of the hermetic container is a discharge pressure atmosphere as a compressor that satisfies the requirement.

In a high-pressure shell type hermetic compressor, the refrigerant gas compressed in the compression chamber is discharged into the sealed container, and then the discharged refrigerant gas is sent to the cycle through a discharge pipe installed in the sealed container. In the process until the refrigerant gas discharged from the compression chamber reaches the discharge pipe, the flow direction and flow velocity can be changed or the centrifugal force of rotation of the main shaft can be changed by changing the configuration and area of the passage through which the refrigerant flows. This is because an oil separating means can be provided. Therefore, the high-pressure shell method can greatly reduce oil rise compared to the low-pressure shell type hermetic compressor that must discharge the entire amount of lubricating oil supplied to the compression chamber. That's it.
JP 2000-274844 A JP 2001-304701 A

  However, when a high-pressure shell type hermetic compressor with low oil rise as described above is used, the inside of the hermetic container is filled with high-temperature discharged refrigerant gas, so that the drive motor and oil sump located inside the hermetic container Are exposed to a high-temperature refrigerant gas, resulting in several problems.

In particular, in a cold water supply refrigerant circulating apparatus using CO ₂ as a refrigerant, a predetermined amount of hot water at a predetermined temperature (eg, 90 ° C.) can be obtained unless the discharge gas temperature is increased to about 150 ° C. depending on environmental conditions. In the case where there is no discharge gas, the discharge gas temperature becomes high.

  When the electric motor is exposed to such high-temperature discharged refrigerant gas, the winding resistance of the electric motor stator increases, so that the electric motor efficiency decreases, or polyethylene terephthalate (PET) or polyethylene naphthalate used in the electric motor stator. Deterioration of resin insulation materials such as phthalate (PEN) is promoted, and in some cases they are extracted, move in the system together with the refrigerant, and accumulate on the narrow tube and filter, causing clogging and system efficiency There is a problem that driving is impossible in the case of decline or worst case.

  In addition, in a DC brushless motor with a built-in magnet in the motor rotor, the magnetic flux density of the magnet is reduced and the efficiency of the motor is reduced, and when a rare earth magnet is used for the magnet, the magnet is demagnetized at a high temperature. This causes the problem of

  Similarly, when the lubricating oil in the oil sump is exposed to a high-temperature refrigerant gas, thermal deterioration of the lubricating oil is promoted, resulting in a decrease in lubricity, precipitation of impurities called sludge, sludge's narrow tube section and filter. The problem arises that the system path is clogged due to the deposition on the part.

  On the other hand, if you control the operating pressure and limit the pressure to prevent the discharge gas temperature from rising, you will not be able to obtain sufficient water heating capacity, or you may use a hermetic compressor or a fan. If the cooling is performed from the outside and the discharge gas temperature is lowered, energy loss is caused, and similarly, sufficient water heating ability cannot be obtained.

  The present invention has been made to solve the above-described problems, and even when a high-pressure shell-type hermetic compressor is used in a refrigerant circulation device using a heat pump cycle used for hot water supply or the like, Refrigerant circulation device that reduces discharge refrigerant gas temperature to a temperature that does not cause problems with electric motors and lubricating oil without reducing the heating capacity for heating fluid such as, and hermetic compressor for use in the refrigerant circulation device The purpose is to provide.

  A refrigerant circulation device according to the present invention is provided in a heat pump cycle for circulating a refrigerant, a radiator that is installed in the heat pump cycle and heats a heated fluid by heat exchange with a high-temperature refrigerant flowing through the heat pump cycle, and a heat pump cycle. A high-pressure shell type hermetic compressor that has a hermetic container and the pressure atmosphere inside the hermetic container becomes discharge pressure, and is formed inside the hermetic container of this hermetic compressor, and each sliding portion of the hermetic compressor is Oil reservoir for storing lubricating oil for lubrication, and a lubricating oil circulation circuit different from the heat pump cycle that passes through the radiator from this oil reservoir and then returns to the suction side that becomes the inlet of the hermetic compressor through the throttle mechanism The oil in the oil sump is circulated in the lubricating oil circulation circuit by the pressure difference between high and low pressure, and the lubricating oil is guided to the radiator to exchange heat with the heating fluid together with the refrigerant. The lubricating oil cooled Te, reduce the pressure by the subsequent diaphragm mechanism, and supplying the lubricating oil to the suction side of the inlet of the hermetic compressor.

  With the above configuration, the refrigerant circulation device according to the present invention uses the heat released from the high-temperature lubricating oil in the oil reservoir to heat the water, so that the discharge gas temperature of the refrigerant is lowered without reducing the heating capacity to the heating fluid. be able to. As a result, the motor efficiency decreases due to high-temperature discharged refrigerant gas, the insulation material used in the motor stator deteriorates, the lubricity decreases due to the thermal deterioration of the lubricating oil in the oil sump, and impurities called sludge are deposited. There is an effect that can be prevented.

Embodiment 1 FIG.
1 to 4 are diagrams showing the first embodiment, FIG. 1 is a schematic diagram showing the configuration of a hot water supply refrigerant circulation device using a heat pump cycle, and FIG. 2 is a high-pressure shell type sealed type used in the refrigerant circulation device. FIG. 3 is a longitudinal sectional view of the compressor, FIG. 3 is a transverse sectional view of the hermetic compressor, and FIG. 4 is a schematic view showing a configuration of a hot water supply refrigerant circulation device using a capillary tube as a second throttle mechanism.

In the hot water supply refrigerant circulation apparatus using the heat pump cycle of FIG. 1, CO ₂ (carbon dioxide), which is a supercritical refrigerant, is used as the refrigerant. As shown in FIGS. 2 and 3, the hermetic compressor 1 used in the heat pump cycle includes a driving motor 11 (having a stator 11 a and a rotor 11 b) in the upper part of the hermetic container 10, and the hermetic container 10. This is a rotary compressor in which a compression mechanism unit 12 for compressing a refrigerant is arranged in the lower part inside. The hermetic compressor 1 directly sucks the sucked refrigerant gas from the suction pipe 13 into the suction chamber 22 formed in the compression mechanism 12 and applies a driving force to the main shaft 14 by the electric motor 11, thereby eccentricizing the rolling piston 23. By rotating and reducing the volume of the compression chamber 24, the refrigerant gas is compressed to the required discharge pressure, and the high-temperature and high-pressure discharge refrigerant gas is discharged from the compression chamber 24 into the sealed container 10. . Thus, the inside of the sealed container 10 is filled with the discharged refrigerant gas, and the pressure atmosphere becomes the discharge pressure. This type of hermetic compressor is generally called a high-pressure shell type, and the hermetic compressor 1 used in the heat pump cycle of the present invention is this high-pressure shell type compressor.

  The bottom of the hermetic container 1 of the hermetic compressor 1 is an oil sump 15 where lubricating oil that lubricates each sliding portion of the hermetic compressor 1 such as a bearing that supports the main shaft 14 in the radial direction is provided. Reserved. The upper surface of the lubricating oil in the oil sump 15 is a so-called oil surface 15a. Lubricating oil is supplied to each sliding portion through an oil hole provided in the axial direction of the main shaft 14 (not shown) due to a pressure difference between the high pressure and the suction pressure inside the sealed container 10 and a centrifugal action caused by rotation of the main shaft 14. In addition, there is a pump that uses a rotation of the main shaft 14 to drive a mechanical pump such as a trochoid pump to pump up lubricating oil. The lubricating oil supplied to the sliding parts is returned to the oil sump 15 again after lubricating each sliding part.

The heat pump cycle 100 in which the CO ₂ refrigerant circulates is a so-called heat pump cycle. In addition to the high-pressure shell-type hermetic compressor 1 that compresses a low-pressure refrigerant into a high-pressure refrigerant, a radiator located on the side where the refrigerant is at a high pressure. 2. A first throttle mechanism 3 for reducing the refrigerant pressure from high pressure to low pressure, and an evaporator 4 located on the low pressure side. The refrigerant gas compressed to high temperature and high pressure by the hermetic compressor 1 and discharged into the cycle by the discharge pipe 16 exchanges heat with water flowing through the water pipe 200 in the radiator 2, and the water is heated to a predetermined temperature. . The heated hot water is stored in a hot water tank (not shown) and is taken out from the hot water tank as needed by the user. In addition, as shown in FIG. 1, the flow direction of a refrigerant | coolant and the flow direction of the water which flows through the inside of the water piping 200 are opposite, and it is comprised so that it may become a flow which mutually opposes inside the heat radiator 2. As shown in FIG.

The first throttle mechanism 3 is composed of a linear expansion valve, the opening degree is adjusted by an electrical signal according to the operating conditions, and the heat exchange with water in the radiator 2 is finished at a high pressure but at a low temperature. _2. Reduce the pressure of the refrigerant to a low-pressure refrigerant. Then, the CO ₂ refrigerant evaporates by exchanging heat with the atmosphere in the evaporator 4. However, 100% of the refrigerant is not always completely gasified, and depending on conditions, there may be a state of a two-phase refrigerant mixed with gas and liquid even after leaving the evaporator 4.

  Since the hermetic compressor 1 is a high-pressure shell type in which the suction refrigerant is directly taken into the compression chamber 24, if a large amount of liquid refrigerant is mixed with the suction refrigerant, the compressor may be damaged by liquid compression. For this reason, the hermetic compressor 1 is provided with an accumulator 17 (having a filter 17a inside) that temporarily stores excess liquid refrigerant at a position before the refrigerant is taken into the compression chamber 24. The gas-liquid of the refrigerant is separated, and only the gas refrigerant is taken into the compression chamber 24. The accumulator 17 is fixed integrally with the hermetic compressor 1 by being welded to a holder 18 that is welded and fixed to the hermetic container 10.

  Next, the lubricating oil circulation circuit 300 that is a feature of the present invention will be described. The lubricating oil circulation circuit 300 opens into the lubricating oil of the oil sump 15 of the hermetic compressor 1, and starts from here through the radiator 2 of the heat pump cycle 100 through a pipe different from the pipe through which the refrigerant passes, Thereafter, it is connected to the suction pipe 13 of the hermetic compressor 1 through the second throttle mechanism 5, and has a circuit configuration with this point as the end point. The oil sump 15 is placed under a discharge pressure atmosphere, and the suction pipe 13 is a suction pressure atmosphere through which the suction refrigerant gas passes. Therefore, a pressure difference is generated here, and the lubricating oil in the oil sump 15 is lubricated by the pressure difference. The oil circulation circuit 300 flows from the oil reservoir 15 toward the suction pipe 13.

  The lubricating oil flowing from the oil sump 15 to the lubricating oil circulation circuit 300 exchanges heat with the water in the water pipe 200 in the radiator 2 in the same manner as the refrigerant flowing in the heat pump cycle 100, and the heat is deprived of the temperature. Reduce (oil temperature). On the other hand, water is heated not only by the refrigerant but also by the amount of heat taken from the lubricating oil. Like the refrigerant, the flow direction of the lubricating oil is configured to face the water flow inside the radiator 2. The lubricating oil whose oil temperature has been lowered is reduced to the suction pressure by the second throttle mechanism 5 and supplied to the suction pipe 13.

The lubricating oil supplied to the suction pipe 13 is directly taken into the compression chamber 24 together with the suction refrigerant gas, and exhibits a sealing effect that prevents leakage of the CO ₂ refrigerant having a large high and low pressure difference. In the case of a rotary compressor, high-pressure refrigerant leaks from the high-pressure side compression chamber 24 during the compression process or from the compression chamber 24 to the low-pressure side suction chamber 22 in the suction refrigerant gas suction process, or a sealed container. There is a leak of the refrigerant gas discharged from the compression chamber 24 inside 10 to the compression chamber 24 and the suction chamber 22. These leaks can be greatly reduced by the lubricating oil supplied to the compression chamber 24 via the lubricating oil circulation circuit 300 sealing the radial gap of the compression chamber 24 and the axial gap between the end faces, The efficiency of the compressor is improved.

  Further, since the lubricating oil that has passed through the lubricating oil circulation circuit 300 is heat-exchanged with water in the radiator 2 to lower its oil temperature, lubricating oil having a temperature close to the discharged refrigerant gas temperature in the oil reservoir 15 is supplied. Unlike the case, low temperature lubricating oil is supplied to the compression chamber 24. Since the lubricating oil is incompressible, the low-temperature lubricating oil takes heat from the compressed refrigerant, and the discharge gas temperature of the refrigerant can be reduced.

  The low-temperature lubricating oil supplied to the compression chamber 24 takes heat from the refrigerant, reduces the discharge gas temperature of the refrigerant, and is discharged into the sealed container 10 from the compression chamber 24 together with the discharge refrigerant gas in a mist form. In the flow in the sealed container 10 until the refrigerant is discharged to the heat pump cycle 100, the refrigerant is separated from the refrigerant and returned to the oil sump 15. Although not shown in order to further promote the separation of the refrigerant discharged from the compression chamber 24 and the lubricating oil in the sealed container 10 and reduce the oil rising out of the heat pump cycle 100 as much as possible, The area of the discharge refrigerant gas passage toward the discharge pipe 16 such as an air hole provided in the laminated steel plate of the stator 11a of the electric motor 11 in the axial direction and the outer circumferential notch (core cut portion) of the laminated steel plate is enlarged, and the discharge refrigerant gas The flow rate is lowered.

  Further, a cup 21 opened on the blade or the counter-motor side is fixed to the upper portion of the rotor 11b of the electric motor 11, and the mixed refrigerant gas of the lubricating oil is caused to be radial by the centrifugal force of the blade and the cup 21 due to the rotation of the rotor 11b. The hermetic compressor 1 incorporates an oil rise prevention measure that gives a flow velocity and then separates the lubricating oil from the density difference between the refrigerant gas and the lubricating oil. These oil rising prevention measures prevent the lubricating oil supplied to the compression chamber 24 from flowing out into the heat pump cycle 100.

  Since the discharge gas temperature of the refrigerant can be reduced, various problems described in the column of problems to be solved by the invention can be solved. That is, it is possible to prevent a decrease in motor efficiency and a deterioration of the insulating material used in the motor stator. Moreover, even when the electric motor 11 is a DC brushless motor and a rare earth magnet is used as the magnet, demagnetization of the magnet can be prevented. From another viewpoint, conventionally, high-grade insulating materials and rare earth magnets that can cope with high discharge gas temperatures have been used. However, in the motor used in the present invention, these grades are reduced. Since the volume of the rare earth magnet can be reduced, the cost reduction effect of the hermetic compressor 1 can be obtained.

  Further, it is possible to prevent deterioration of lubricity due to thermal deterioration of the lubricating oil in the oil sump 15 and precipitation of impurities called sludge. The reduction of the discharge refrigerant gas temperature also reduces the temperature of the sealed container 10 containing the discharged gas, so that the temperature difference between the sealed container 10 and the outside air is reduced, and the heat radiation from the sealed container 10 to the outside air is reduced. Leads to a decrease. Since the heat radiation from the sealed container 10 to the outside air is a heat loss, this reduction improves the heat insulation efficiency of the system and increases the heating capacity.

By reducing the refrigerant discharge gas temperature, the heat exchange amount of the refrigerant and water in the radiator ₂ is reduced, and the water heating capacity of the CO ₂ refrigerant itself in the radiator 2 is reduced. Since the heat radiation of the hot lubricating oil in the reservoir 15 is used for heating the water, the overall water heating capacity of the hot water supply system does not decrease compared to the conventional case. Even if the discharge gas temperature of the refrigerant is reduced, the heat amount of the lubricating oil is used for heating the water without being discarded, so that the system heating capacity can be maintained as in the conventional case.

  The second throttle mechanism 5 of the lubricating oil circulation circuit 300 uses a capillary tube 5a as shown in FIG. 4 as the most inexpensive configuration. However, when the capillary tube 5a is used, the resistance value of the lubricating oil passage is always constant, and therefore, the circulation amount of the lubricating oil is determined only by the differential pressure between the discharge pressure and the suction pressure. Only the change in the operating condition, that is, the change in the differential pressure between the discharge pressure and the suction pressure, causes a change in the circulation amount of the lubricating oil circulating in the lubricating oil circulation circuit 300. If the differential pressure is large, the lubricating oil circulation rate increases. Basically, if the differential pressure is large, a large amount of oil is required for sealing. Therefore, if the hermetic compressor 1 is a constant speed machine operated at a constant speed (rotation speed 50 Hz or 60 Hz), the second The throttling mechanism 5 may be composed of the capillary tube 5a, thereby reducing the cost of the hot water supply system.

  In the refrigerant circulation device of the above-described embodiment, the hermetic compressor 1 is a high-pressure shell type compressor, and the lubricating oil circulation circuit 300 is configured separately from the heat pump cycle 100 (refrigerant circulation circuit). The lubricating oil in the oil sump 15 is guided to the radiator 2 by a pressure difference, and heat is exchanged with the heating fluid together with the refrigerant to cool the lubricating oil, and then the pressure is reduced by the second throttle mechanism 5. Since the lubricating oil is supplied to the suction pipe 13 serving as the inlet and the heat release from the high-temperature lubricating oil in the oil sump 15 is used for heating the water, the refrigerant discharge gas is not reduced without reducing the heating capacity to the heating fluid. The temperature can be lowered. For this reason, the motor efficiency is reduced due to the high-temperature discharged refrigerant gas, the insulating material used for the stator 11a of the motor 11 is deteriorated, and the lubricity is reduced due to the thermal deterioration of the lubricating oil in the oil sump 15, and sludge. There is an effect of preventing precipitation of impurities called.

Embodiment 2. FIG.
FIGS. 5 and 6 are diagrams showing the second embodiment, FIG. 5 is a schematic diagram showing a configuration of a hot water supply refrigerant circulating apparatus using a heat pump cycle, and FIG. 6 is a weight% of the lubricating oil supplied to the compression chamber with respect to the refrigerant. It is a figure which shows the relationship between discharge gas temperature and illustration efficiency. In the description of the hermetic compressor 1, only the motor is different, and therefore FIGS. 2 and 3 of the first embodiment are used.
In recent years, a variable speed machine using an inverter tends to be used for the hermetic compressor 1 so that the compressor used in the hot water supply system can also respond sensitively to the state of the outside air from the viewpoint of energy saving. Furthermore, in order to increase the efficiency of the hermetic compressor 1, a DC brushless motor 31 having a high motor efficiency in which a ferrite magnet or a rare earth magnet is incorporated in the rotor may be used for the motor. The compressor 1 uses a variable speed compressor using a DC brushless motor 31 as an electric motor. However, this includes those in which induction machines are driven by inverters.

  When the hermetic compressor 1 is compatible with the variable speed, if the capillary tube 5a is used for the second throttle mechanism 5, the circulation amount of the lubricating oil can be changed only by the pressure difference between the discharge pressure and the suction pressure. It cannot respond to changes. If the capillary tube 5a adjusted to have the optimum resistance at the time of operation at a rating of 50 Hz or 60 Hz is used, the time for one rotation is delayed at low speed operation, so that the amount of lubricating oil supplied to the compression chamber 24 is excessive. On the contrary, the supply amount becomes too small during high-speed operation.

  If the amount of low-temperature lubricating oil supplied to the compression chamber 24 through the lubricating oil circulation circuit 300 becomes excessive, the reduction of the refrigerant discharge gas temperature becomes too large, and the heating necessary to heat the predetermined amount of water to the predetermined temperature. The ability cannot be obtained. Further, since the ratio of the volume of the refrigerating machine oil in the mixed volume of the refrigerant and the refrigerating machine oil taken into the compression chamber 24 becomes larger, the volume efficiency of the compressor is lowered, thereby reducing the refrigerant circulation amount of the heat pump cycle 100. By doing so, the ability to heat water decreases. Further, if the amount of lubricating oil in the discharge gas from the compression chamber 24 is excessive, oil separation from the refrigerant in the sealed container 10 cannot be performed sufficiently, oil rise increases, and the water and refrigerant of the heat pump cycle 100 increase. Problems such as hindering heat exchange and lowering of heating capacity occur.

  Conversely, if the supply amount of the lubricating oil to the compression chamber 24 is insufficient, the discharge gas temperature of the refrigerant does not decrease, and the invention to be solved by the invention in which the electric motor and the lubricating oil are exposed to a high temperature atmosphere is described in the column of problems to be solved. However, the sealing effect of the compression chamber 24 is reduced, the refrigerant leakage in the compression chamber 24 is increased, and the illustration efficiency of the compressor is lowered. Therefore, the efficiency of the system is lowered. Arise.

  Therefore, in the second embodiment, a variable speed compressor using a DC brushless motor 31 is used for the hermetic compressor 1, and the opening degree of the second throttle mechanism 5 of the lubricating oil circulation circuit 300 is determined by an electrical signal. The electromagnetic valve 5b that can adjust the angle is used. Then, using the operating speed of the compressor and the operating conditions of the discharge pressure and the suction pressure as control factors, the opening degree of the electromagnetic valve 5b is adjusted, and the amount of lubricating oil circulating through the lubricating oil circulation circuit 300 is optimized. Here, the optimum circulation amount of the lubricating oil needs to be determined by two independent factors. One is the refrigerant discharge gas temperature. If it is too low, the heating capacity is insufficient, and if it is too high, the electric motor and lubricating oil are adversely affected. The other is the sealing performance (illustration efficiency) of the compression chamber 24. When the amount of oil is small, leakage increases and the efficiency of illustration decreases, and when it is too large, the volumetric efficiency decreases and the heating capacity becomes insufficient.

  The discharge refrigerant gas temperature can be grasped by attaching the discharge refrigerant gas temperature detection means 20 such as a temperature sensor in the vicinity of the discharge pipe 16 and the discharge pipe 16 of the pipe of the heat pump cycle 100 connected to the discharge pipe 16, Since it can be converted into an electrical signal, this may be used as a control factor for adjusting the opening of the electromagnetic valve 5b, which is the second throttle mechanism 5. Although not shown in the drawing, the temperature of the discharged refrigerant gas is not detected, but a temperature detecting means such as a temperature sensor is installed on the outer wall of the sealed container 10 to grasp the temperature of the outer wall of the sealed container, and this is used as a control factor. 5 may be used for adjusting the opening of the solenoid valve 5b.

  According to the mounting test on the actual hot water supply cycle and the test of the compressor alone, under all circumstances assumed in the market, the lower limit side of the rotational speed must be more lubricated to the compression chamber 24 than the upper limit side. Although there is a tendency that the reduction in the efficiency of illustration due to leakage tends to be large, the amount of lubricating oil supplied to the compression chamber 24 through the lubricating oil circulation circuit 300 over the entire area from the lower limit to the upper limit is in weight ratio to the refrigerant. An amount of 10-20% has been found desirable (see FIG. 6). This means that X / (R + X) = 10 to 20% is appropriate when the weight of the refrigerant taken into one compression chamber 24 is R and the weight of the lubricating oil is X. Accordingly, the adjustment of the opening degree of the electromagnetic valve 5b of the second throttle mechanism 5 is performed so that the amount of lubricating oil supplied to the compression chamber 24 is 10 to 20% by weight, and the discharge pressure is the operating rotational speed and operating pressure. And the suction pressure, or in addition thereto, the discharge gas temperature or the outer wall temperature of the sealed container is used as a control factor to adjust the circulation amount of the lubricating oil circulating in the lubricating oil circulation circuit 300.

  It is not always necessary to use all of the above physical quantities as control factors. Since the cost can be reduced if the number of control factors is small, it is important to maintain the heating capacity, and only the discharge refrigerant gas temperature or the temperature of the outer wall of the sealed container may be used as the control factor. The hermetic compressor 1 is a constant speed machine. In this case, the second throttle mechanism 5 is configured by a capillary tube so that the amount of lubricating oil supplied to the compression chamber 24 can be made appropriate. The opening degree of the electromagnetic valve 5b may be adjusted. In addition, in order to add the operating pressures of the discharge pressure and the suction pressure to make the accuracy higher than one physical quantity, the operating pressure and the discharge gas temperature or the temperature of the outer wall of the sealed container may be used as control factors. May be used as a control factor.

  Since the opening of the second throttle mechanism 5 of the lubricating oil circulation circuit 300 is an electromagnetic valve 5b whose opening can be adjusted according to the rotational speed of the compressor and operating conditions, it is always compatible with a variable speed compressor. Since the amount of lubricating oil supplied to the compression chamber 24 through the lubricating oil circulation circuit 300 can be optimized, the discharge gas temperature may be lowered as the water heating capacity is reduced, and vice versa. Therefore, it is possible to maintain an appropriate discharge gas temperature that does not damage the electric motor and the lubricating oil without reducing the discharge gas temperature. The heating amount of water in the refrigerant circulation circuit, that is, the heat pump cycle 100 alone is lower than that in the conventional heat pump cycle in which the refrigerant discharge gas temperature is increased to about 150 ° C., but the lubricating oil circulation circuit 300 performs lubrication. Since the amount of heat of oil is used for heating water, the heating capacity can be maintained as in the conventional system as a whole system.

  Even when a capillary tube is used in the second throttle mechanism 5 of the lubricating oil circulation circuit 300 in the first embodiment, the resistance value determined by the inner diameter and length of the tube is supplied to the compression chamber 24 via the lubricating oil circulation circuit 300. Tuning is performed so that the amount of lubricating oil is 10 to 20% by weight. Although the cost increases, even when a constant speed machine is used for the hermetic compressor 1, the second throttle mechanism 5 uses an electromagnetic valve whose opening degree can be adjusted to circulate the lubricating oil circulation circuit 300. If the amount of oil is controlled, an operation with higher accuracy in the amount of oil supplied to the compression chamber 24 becomes possible.

  In Patent Document 2, an oil recirculation passage is formed in which the lubricating oil separated by the oil separator is returned from the oil separator to the compressor through the radiator, and the amount of heat of the lubricating oil returning from the oil separator to the compressor is determined. Although it is described that a highly efficient hot water system with little heat loss can be obtained by heating water with a radiator, the present invention supplies lubricating oil to the compression chamber 24 in order to eliminate the need for an oil separator. In order to reduce the discharge gas temperature without reducing the heating capacity to the heated fluid, the oil reservoir of the compressor is used. A lubricating oil circulation circuit starting from the compressor suction side is formed, and the heat quantity of the lubricating oil is used for heating the water by a radiator in the lubricating oil circulation circuit. Furthermore, the lubricating oil circulation circuit The aperture mechanism The amount of lubricating oil supplied to the compression chamber 24 is controlled by adjusting the amount of lubricating oil circulating in the lubricating oil circulation circuit by adjusting the resistance of the throttle mechanism. Is.

Embodiment 3 FIG.
7-9 is a figure which shows Embodiment 3, and is the schematic which shows the structure of a refrigerant circulation apparatus.
In the first and second embodiments, the inlet and outlet of the lubricating oil in the lubricating oil circulation circuit 300 and the refrigerant in the heat pump cycle 100 to the radiator 2 are the same. If it is important to set the amount of lubricating oil supplied to the chamber 24 to 10 to 20% by weight, the temperature of the lubricating oil to be supplied is excessively reduced by heat exchange with water in the radiator 2, and the discharge gas temperature Depending on the capacity of the system, there may be a situation in which the heating capacity is reduced due to excessive reduction of the temperature. In such a case, it is possible to recover the heating capacity by lowering the supply oil amount to less than 10% and raising the discharge gas temperature to an appropriate temperature, but at this time, the amount of lubricating oil in the compression chamber Therefore, the refrigerant leakage increases, and the efficiency of the compressor illustration decreases.

  The lubricating oil circulation circuit 300 for such a hot water supply system is configured to pass only an arbitrary part of the radiator 2 instead of the entire radiator 2 to prevent the oil temperature of the lubricating oil from excessively decreasing. It is only necessary to obtain an appropriate lubricating oil temperature. For example, as shown in FIG. 7, the lubricating oil circulation circuit 300 assumes that the inlet of the radiator 2 is the same as the heat pump cycle 100, and is closer to the outlet (closer to the inlet) than the outlet of the radiator 2 of the heat pump cycle 100. You may leave.

  Further, as shown in FIG. 8, the lubricating oil circulation circuit 300 is arranged in the middle of the radiator 2, that is, after the inlet of the radiator 2 of the heat pump cycle 100 (closer to the outlet), with the outlet in common with the reverse of FIG. 7. The heat radiator 2 may be configured to pass through.

  Further, as shown in FIG. 9, the inlet and the outlet are not common, and the lubricating oil circulation circuit 300 is disposed in the middle of the radiator 2, that is, after the radiator 2 in the heat pump cycle 100 (closer to the outlet). 2, and may be configured to be separated from the radiator 2 in front of the outlet of the radiator 2 of the heat pump cycle 100 (closer to the inlet).

Embodiment 4 FIG.
FIG. 10 is a diagram showing the fourth embodiment, and is a schematic diagram showing the configuration of the refrigerant circulation device.
In the first to third embodiments, the end point of the lubricating oil circulation circuit 300, that is, the position where the lubricating oil circulated through the lubricating oil circulation circuit 300 is supplied to the suction side of the hermetic compressor 1 is the accumulator 17 and the compression chamber 24. It was the suction pipe 13 which connects. By supplying the lubricating oil whose oil temperature has been lowered, the refrigerant discharge gas temperature is lowered. Therefore, a position closer to the compression chamber 24 is desirable so that heat is not applied to the lubricating oil from the hermetic compressor 1. In this respect, it can be said that the suction pipe 13 is the most suitable position. However, in the fourth embodiment, as shown in FIG. 10, the lubricating oil circulation is provided in the suction side pipe located in the vicinity of the accumulator 17 on the upstream side of the accumulator 17. The lubricating oil that has passed through the circuit 300 is supplied. A filter 17a is provided inside the accumulator 17, and foreign substances in the circuit can be removed here.

  In the fourth embodiment, the lubricating oil that has passed through the lubricating oil circulation circuit 300 is supplied to the suction pipe on the upstream side of the filter 17a, so that the supplied lubricating oil passes through the accumulator 17 before being supplied to the compression chamber 24. In this case, since it passes through the filter 17a, foreign matters such as iron powder and copper powder mixed in the lubricating oil can be removed here, so that these foreign matters can be prevented from being mixed into the compression chamber 24, and the rolling piston can be prevented. It is possible to prevent the hermetic compressor 1 from being locked (stopped operation) due to the biting of foreign matter.

Embodiment 5. FIG.
11 and 12 show the fifth embodiment. FIG. 11 is a longitudinal sectional view of a two-cylinder rotary compressor, and FIG. 12 is a longitudinal sectional view of a scroll compressor.
The lubricating oil circulation circuit 300 shown in the above embodiment is the high pressure inside the sealed container 10 and the end point of the lubricating oil circulation circuit 300 from the oil sump 15 at the bottom of the sealed container 10 of the hermetic compressor 1. The lubricating oil is guided into the lubricating oil circulation circuit 300 by the pressure difference from the suction side. However, as shown in FIG. 2, an oil reservoir inside the sealed container 10 is formed on the outer wall of the sealed container 10 of the hermetic compressor 1. 15 and a lubricating oil outlet pipe 19 for connecting the lubricating oil circulation circuit 300 are provided. One end of the lubricating oil lead-out pipe 19 is open to the oil sump 15 and is positioned as close to the bottom as possible so that the lubricating oil can be reliably opened even if the oil level 15a of the lubricating oil drops during operation. Attached to. The other is opened to the outside of the hermetic container 10 and the other opening 19a is connected to the piping of the lubricating oil circulation circuit 300 by brazing or the like.

  Here, the opening 19 a outside the sealed container 10 of the lubricating oil outlet pipe 19 is arranged at a position higher than the oil surface 15 a of the oil reservoir 15. When the hot water supply system is manufactured in a factory, the hermetic compressor 1 is filled with lubricating oil, and the opening 19a is positioned higher than the oil level at this time, that is, the initial oil level. Until the piping of the lubricating oil circulation circuit 300 is connected to the opening 19a, a rubber plug or the like is press-fitted into the opening 19a. In the manufacturing process of the hot water supply system, the rubber plug is removed, and the piping of the lubricating oil circulation circuit 300 is brazed to the opening 19a. When the rubber plug is removed, the opening 19a extends from the oil surface 15a at that time. Therefore, the lubricating oil does not spill out from the opening 19a, there is no shortage of the amount of lubricating oil due to outflow, and the brazing operation is performed safely and hygienically. It can be carried out.

  In each of the above embodiments, a single-cylinder rotary compressor is used as the hermetic compressor 1. However, the present invention is not limited to this, and a high-pressure shell-type hermetic compressor in which the inside of the hermetic container has a discharge pressure atmosphere. As long as it is not limited to a single-cylinder rotary compressor, it may be a multi-cylinder rotary compressor (an example is shown in FIG. 11) or a scroll compressor (an example is shown in FIG. 12). The configuration of the present invention is applied to any compressor that maintains an intermediate pressure higher than the suction pressure so that the lubricating oil can circulate in the lubricating oil circulation circuit by the differential pressure even if the inside of the compressor is not in the discharge pressure atmosphere. A similar effect can be obtained.

The refrigerant circulation device of the embodiment is a hot water supply system using a CO ₂ refrigerant. However, the present invention can be applied not only to this application but also to other refrigerants. Even when the configuration of the present invention is applied to a general heat pump cycle in which the high pressure side used for air conditioning applications is less than supercritical pressure and the refrigerant condenses, the discharge is not reduced. This is effective as a means for lowering the refrigerant gas temperature.

It is a figure which shows Embodiment 1, and is the schematic which shows the structure of the refrigerant circulating apparatus for hot water supply using a heat pump cycle. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows Embodiment 1, and is a longitudinal cross-sectional view of the high pressure shell type hermetic compressor used for a refrigerant circulation device. FIG. 2 is a diagram showing the first embodiment, and is a cross-sectional view of a high-pressure shell type hermetic compressor used in the refrigerant circulation device. FIG. 5 shows the first embodiment, and is a schematic diagram showing a configuration of a hot water supply refrigerant circulating apparatus using a capillary tube as a second throttling mechanism. It is a figure which shows Embodiment 2, and is the schematic which shows the structure of the hot water supply refrigerant | coolant circulating apparatus using a heat pump cycle. FIG. 6 is a diagram illustrating the second embodiment and is a diagram illustrating a relationship between the weight% of the lubricating oil supplied to the compression chamber with respect to the refrigerant, the discharge gas temperature, and the illustrated efficiency. It is a figure which shows Embodiment 3, and is the schematic which shows the structure of a refrigerant circulation apparatus. It is a figure which shows Embodiment 3, and is the schematic which shows the structure of a refrigerant circulation apparatus. It is a figure which shows Embodiment 3, and is the schematic which shows the structure of a refrigerant circulation apparatus. It is a figure which shows Embodiment 4, and is the schematic which shows the structure of a refrigerant circulation apparatus. FIG. 10 is a diagram illustrating the fifth embodiment and is a longitudinal sectional view of a two-cylinder rotary compressor. It is a figure which shows Embodiment 5, and is a longitudinal cross-sectional view of a scroll compressor.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Hermetic compressor, 2 Heat radiator, 3 1st aperture mechanism, 4 Evaporator, 5 2nd aperture mechanism, 5a Capillary tube, 5b Solenoid valve, 10 Airtight container, 11 Electric motor, 11a Stator, 11b Rotor, 12 Compression mechanism, 13 suction pipe, 14 main shaft, 15 oil sump, 15a oil level, 16 discharge pipe, 17 accumulator, 17a filter, 18 holder, 19 lubricating oil outlet pipe, 19a opening, 20 discharged refrigerant gas temperature detecting means, 21 Cup, 22 Suction chamber, 23 Rolling piston, 24 Compression chamber, 31 DC brushless motor, 100 Heat pump cycle, 200 Water piping, 300 Lubricating oil circulation circuit.

Claims (12)

A heat pump cycle for circulating the refrigerant;
A radiator that is installed in the heat pump cycle and heats the heating fluid by heat exchange with a high-temperature refrigerant flowing through the heat pump cycle;
A high-pressure shell-type hermetic compressor that is provided in the heat pump cycle, has a hermetic container, and a pressure atmosphere inside the hermetic container becomes a discharge pressure;
An oil sump that is formed inside the hermetic container of the hermetic compressor and stores lubricating oil for lubricating each sliding portion of the hermetic compressor;
A lubricating oil circulation circuit different from the heat pump cycle, which passes through the heat sink from the oil reservoir and then returns to the suction side which becomes the inlet of the hermetic compressor through a throttle mechanism,
And circulating the lubricating oil in the oil reservoir to the lubricating oil circulation circuit by a pressure difference between high and low pressure, guiding the lubricating oil to the radiator, heat-exchanging with the heating fluid together with the refrigerant, and cooling the lubricating oil, Thereafter, the refrigerant is depressurized by the throttling mechanism, and the lubricating oil is supplied to the suction side serving as the inlet of the hermetic compressor.   The throttle mechanism is an electromagnetic valve whose opening degree can be adjusted, and the amount of the lubricating oil circulating in the lubricating oil circulation circuit is adjusted by adjusting the opening degree of the electromagnetic valve, and the suction side of the hermetic compressor The refrigerant circulation device according to claim 1, wherein the amount of the lubricating oil supplied to the refrigerant is controlled.   The heat pump cycle has at least one of a discharge refrigerant gas temperature detection means for detecting a discharge refrigerant gas temperature in a discharge side pipe or a closed container temperature detection means for detecting a closed container temperature on an outer wall of the closed container. 3. The refrigerant circulation device according to claim 2, wherein the opening degree of the electromagnetic valve is adjusted by using information on the discharged refrigerant gas temperature or the closed container temperature obtained from the temperature detecting means as a factor.   3. The refrigerant circulation device according to claim 2, wherein the hermetic compressor is a variable speed compressor, and the opening degree of the electromagnetic valve is adjusted by using information on the operating rotational speed of the compressor as a factor.   4. The refrigerant circulation device according to claim 3, wherein the opening degree of the electromagnetic valve is adjusted by adding information on discharge pressure and suction pressure, which are operating pressures, to factors.   The hermetic compressor is a variable speed compressor, and the opening degree of the solenoid valve is adjusted by a plurality of factors including information on the operating rotational speed of the compressor and information on discharge pressure and suction pressure as operating pressure. The refrigerant circulating apparatus according to claim 2.   6. The refrigerant circulation device according to claim 5, wherein the opening degree of the electromagnetic valve is adjusted by adding information on the operating rotational speed of the hermetic compressor to a factor.   2. The refrigerant circulation device according to claim 1, wherein the lubricating oil circulation circuit passes through a radiator only in a part of a range in which the refrigerant passes through the radiator.   9. The amount of lubricating oil that circulates in the lubricating oil circulation circuit and is supplied to the suction side of the hermetic compressor is in the range of 10 to 20% by weight with respect to the refrigerant. The refrigerant circulation device according to any one of the above.   10. The hermetic compressor includes an accumulator having a filter therein, and a position where the lubricating oil circulated through the lubricating oil circulation circuit is returned to the suction side is an upstream side of the accumulator. The refrigerant circulation device according to any one of the above.   The refrigerant circulation device according to claim 1, wherein carbon dioxide, which is a supercritical refrigerant, is used as the refrigerant, and the heating fluid is a hot water supply system that is water. In the hermetic compressor in which the pressure atmosphere inside the hermetic container is a discharge pressure, and the lubricating oil is stored in the oil sump at the bottom of the hermetic container,
One opening opens to the lubricating oil in the oil reservoir, the other opens to the outside of the hermetic container, and a lubricating oil outlet pipe for leading the lubricating oil from the oil reservoir to the outside of the hermetic container A hermetic compressor provided at the bottom, wherein the position of the opening to the other outside is higher than the oil level of the lubricating oil in the oil sump.

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