JP2005098554A - Heat pump cycle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To maintain a high coefficient of result even if atmospheric temperature is changed by changing internal heat exchange quantity without using electric control. <P>SOLUTION: A container 7a is provided with a gas-liquid separator communication passage 7b in a side surface thereof, a compressor communication passage 7c in a top side thereof and an internal heat exchanger communication passage 7d in a ground side thereof. A float 71 having the predetermined density is provided inside the container 7a, and a flow passage changing means 7 for changing a refrigerant flow passage flowing to the compressor communication passage 7c and the internal heat exchanger communication passage 7d by vertically moving the float 71 in response to density of the refrigerant flowing from the gas-liquid separator communication passage 7b is arranged to control heat exchange quantity in an internal heat exchanger 6. Even if atmospheric temperature is changed, a high coefficient of result can be always maintained by changing quantity of the refrigerant flowing to the internal heat exchanger 6 with the float 71 vertically moving in response to density of the refrigerant to adjust quantity of the refrigerant to the internal heat exchange quantity corresponding to the pressure of the refrigerant (evaporation temperature of the refrigerant). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a heat pump cycle that moves heat on a low temperature side to a high temperature side, and is effective when applied to an air conditioner or a hot water supply device.

  Conventionally, as means for improving the capacity of a heat pump cycle (refrigeration cycle), means for providing an internal heat exchanger for exchanging heat between the high-pressure refrigerant before being decompressed and the low-pressure refrigerant sucked into the compressor is known. The internal heat exchanger reduces the specific enthalpy of the refrigerant at the evaporator inlet by cooling the high-temperature and high-pressure refrigerant flowing into the decompression means such as the expansion valve with the low-temperature and low-pressure refrigerant sucked into the compressor. The amount of change in specific enthalpy (heat absorption capacity) at the gas cooler is increased, and the specific enthalpy change (heat release amount) at the gas cooler is increased by increasing the specific enthalpy of the refrigerant at the inlet of the gas cooler.

However, since the internal heat exchanger heats the refrigerant sucked into the compressor, the density of the refrigerant sucked into the compressor is lowered, the mass flow rate circulating in the cycle is lowered, and instead the heat pump cycle (refrigeration). Cycle) ability may be reduced. Therefore, the present applicant has previously applied for the heat pump cycle provided with the internal heat exchanger shown in Patent Document 1. This is because the heat pump cycle (refrigeration cycle) capacity is improved (maintains a high coefficient of performance) at high loads with high air temperatures and low loads with low air temperatures. The amount is variably controlled.
Japanese Patent Laid-Open No. 2002-349977

  However, in the above-mentioned Patent Document 1, an electric valve means is used for flow rate adjustment for variably controlling the heat exchange amount, and there is a problem of cost increase due to a variable control sensor, motor (or solenoid), control circuit, etc. It becomes. The present invention has been made in view of this problem, and its purpose is to change the internal heat exchange amount without using electrical control, so that a high coefficient of performance is always obtained even if the air temperature changes. The object is to provide a heat pump cycle (refrigeration cycle) that can be maintained.

In order to achieve the above object, the present invention employs technical means described in claims 1 to 3. That is, according to the first aspect of the present invention, the compressor (1) that sucks and compresses the refrigerant, the radiator (2) that cools the refrigerant discharged from the compressor (1), and the refrigerant is evaporated to absorb heat. The evaporator (3), the nozzle (41) for converting the pressure energy of the high-pressure refrigerant flowing out from the radiator (2) into velocity energy and decompressing and expanding the refrigerant, and the high-speed refrigerant flow injected from the nozzle (41) The vapor phase refrigerant evaporated in the evaporator (3) is sucked by the above, and the velocity energy is converted into pressure energy while the refrigerant injected from the nozzle (41) and the refrigerant sucked from the evaporator (3) are mixed. An ejector (4) having a boosting section (4a, 4b) for boosting the pressure of
A gas-liquid separator (5) that separates the refrigerant into a gas-phase refrigerant and a liquid-phase refrigerant and stores the refrigerant, a high-pressure refrigerant that has flowed out of the radiator (2), and a low-pressure refrigerant that is sucked into the compressor (1). In a heat pump cycle comprising an internal heat exchanger (6) for exchanging heat, and moving heat on the low temperature side to the high temperature side using a refrigerant whose endotherm in the evaporator (3) is in the condensation region,
The gas-liquid separator communication path (7b) into which refrigerant from the gas-liquid separator (5) flows is supplied to the side surface of the container (7a), and the refrigerant is supplied to the compressor (1) on the top side of the container (7a). An internal heat exchanger communication path (7d) for supplying refrigerant to the compressor (1) via the internal heat exchanger (6) is provided on the ground side of the compressor communication path (7c) and the container (7a). At the same time, a float (71) having a predetermined density is provided in the container (7a), and the float (71) moves up and down depending on the density of the refrigerant flowing from the gas-liquid separator communication path (7b), whereby the compressor communication path (7c). And a flow path varying means (7) for varying the flow path of the refrigerant flowing through the internal heat exchanger communication path (7d), a gas-liquid separator (5), a compressor (1), and an internal heat exchanger (6). It arrange | positions between these, It was characterized by adjusting the heat exchange amount in an internal heat exchanger (6).

  FIG. 1 is a schematic diagram of a heat pump cycle in one embodiment of the present invention, and FIG. 4 is a Mollier diagram in the heat pump cycle of FIG. In the present invention, chlorofluorocarbon, alternative chlorofluorocarbon, natural refrigerant or the like is used as the refrigerant, and the heat absorption in the evaporator (3) is in the condensation region. In such a heat pump cycle (refrigeration cycle), the refrigerant state at the gas-liquid separator (5) outlet is on the saturated vapor line, and the refrigerant density is uniquely determined by the refrigerant pressure (refrigerant evaporation temperature). The float (71) of a predetermined density is moved up and down in the container (7a) by using the above, and the flow path passing through the internal heat exchanger (6) and the flow path not passing through are changed.

  More specifically, when the outlet pressure of the gas-liquid separator (5) is low (air temperature is low), the float (71) becomes heavier than the refrigerant and sinks in the container (7a), so The passage (7d) is closed, and the refrigerant is directly introduced into the compressor (1) from the compressor communication passage (7c). Further, when the pressure at the outlet of the gas-liquid separator (5) is high (the air temperature is high), the float (71) is lighter than the refrigerant and floats in the container (7a), thereby closing the compressor communication path (7c). As a result, the refrigerant can be introduced into the internal heat exchanger (6) from the internal heat exchanger communication path (7d).

  FIG. 5 shows the relationship between the air temperature Tam on the upstream side of the air flow of the radiator 2 (front surface of the radiator 2) and the coefficient of performance of the cycle (COP = refrigeration capacity generated in the evaporator / compressor work). It is a numerical simulation result, a dashed-dotted line shows the case where a high pressure refrigerant | coolant and a low pressure refrigerant are always heat-exchanged, a broken line shows the case where it does not have an internal heat exchanger, and the continuous line has shown this embodiment. As apparent from FIG. 5, according to the present embodiment, the high-pressure refrigerant and the low-pressure are based on the air temperature Tam on the upstream side of the air flow of the radiator 2 (the front surface of the radiator 2), which is a physical quantity related to the high-pressure refrigerant. Since the amount of heat exchange with the refrigerant is variable, the coefficient of performance of the cycle can always be kept high.

  According to the first aspect of the present invention, the refrigerant pressure flowing into the internal heat exchanger (6) can be varied by the float (71) that rises and falls depending on the refrigerant density without using electrical control, and the refrigerant pressure By adjusting the internal heat exchange amount according to (evaporation temperature of refrigerant), a heat pump cycle (refrigeration cycle) that can always maintain a high coefficient of performance (COP) even if the air temperature (Tam) changes. be able to.

  The invention according to claim 2 is characterized in that the flow path varying means (7) is applied to a heat pump cycle in which the refrigerant at the outlet of the evaporator is always in a saturated vapor state, and the invention according to claim 3 Then, the flow path varying means (7) is characterized by being applied to a heat pump cycle in which the refrigerant in the compressor suction portion is always in a saturated vapor state.

  The present invention can be applied to a heat pump cycle other than the ejector cycle as long as the refrigerant in the evaporator outlet or the compressor suction portion is always in a saturated vapor state. According to the invention described in claim 2 or claim 3, even in a heat pump cycle other than the ejector cycle, even if the air temperature (Tam) changes, a higher coefficient of performance (COP) can be more reliably maintained. it can. In addition, the code | symbol in the bracket | parenthesis of each said means is an example which shows a corresponding relationship with the specific means as described in embodiment mentioned later.

(First embodiment)
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram of a heat pump cycle using an ejector 4 according to an embodiment of the present invention. In the present embodiment, an ejector cycle (heat pump cycle) according to the present invention is replaced with chlorofluorocarbon, alternative chlorofluorocarbon, natural refrigerant, and the like. The present invention is applied to an air conditioner used as a refrigerant. Reference numeral 1 in FIG. 1 denotes a variable capacity compressor that obtains driving force from a driving source (not shown) such as a driving motor or an engine and sucks and compresses the refrigerant. Reference numeral 2 denotes a radiator (high-pressure side heat exchanger, condenser) that cools the refrigerant by exchanging heat between the refrigerant discharged from the compressor 1 and outdoor air.

  3 is an evaporator (low pressure side heat exchanger, evaporator) that performs heat exchange between the air blown into the room and the liquid phase refrigerant, and absorbs heat from the air blown into the room by evaporating the liquid phase refrigerant to exert a refrigerating capacity. is there. The ejector 4 expands the refrigerant flowing out of the radiator 2 under reduced pressure and sucks the gas-phase refrigerant evaporated in the evaporator 3, and converts the expansion energy into pressure energy to increase the suction pressure of the compressor 1. (Pressure reduction means).

  Here, as shown in FIG. 2, the ejector 4 converts the pressure energy (pressure head) of the high-pressure refrigerant flowing out from the radiator 2 into velocity energy (speed head), and decompresses and expands the refrigerant in a substantially isentropic manner. The nozzle 41 to be discharged, the mixing unit 4a for sucking the vapor-phase refrigerant evaporated in the evaporator 3 by the high-speed refrigerant flow (jet flow) jetted from the nozzle 41, and the refrigerant jetted from the nozzle 41 and the suction from the evaporator 3 It is composed of a boosting section such as a diffuser section 4b that boosts the pressure of the refrigerant by converting velocity energy into pressure energy while mixing with the refrigerant.

  Incidentally, the nozzle 41 according to the present embodiment has a throat portion 41a having the smallest passage area in the middle of the passage, and the dimension from the throat portion 41a to the outlet of the nozzle 41 starts to reduce the passage sectional area. A divergent nozzle larger than the dimension from the throat portion 41a to the throat portion 41a. In the present embodiment, the diameter of the mixing portion 4a is constant up to the diffuser portion 4b. However, the cross-sectional area of the mixing portion 4a may be tapered so as to increase toward the diffuser portion 4b.

  Further, since the sum of the momentum of the driving flow refrigerant blown from the nozzle 41 and the momentum of the suction flow refrigerant sucked from the evaporator 3 to the ejector 4 is preserved, the driving flow refrigerant and the suction flow refrigerant are mixed. The refrigerant pressure (static pressure) also increases in the mixing unit 4a. On the other hand, in the diffuser portion 4b, as described above, the velocity energy (dynamic pressure) of the refrigerant is converted into pressure energy (static pressure) by gradually increasing the cross-sectional area of the passage. The refrigerant pressure is increased by both 4a and the diffuser section 4b. Therefore, the mixing unit 4a and the diffuser unit 4b are collectively referred to as a boosting unit.

  Further, reference numeral 5 in FIG. 1 denotes a gas-liquid separator that stores the refrigerant by flowing the refrigerant flowing out from the ejector 4 and storing the refrigerant by separating the flowing refrigerant into a gas-phase refrigerant and a liquid-phase refrigerant. The phase refrigerant is sucked into the compressor 1 and the separated liquid refrigerant is sucked into the evaporator 3 side. The refrigerant passage 3a connecting the gas-liquid separator 5 and the evaporator 3 is a capillary for reducing the pressure of the refrigerant sucked by the evaporator 3 and reliably reducing the pressure (evaporation pressure) in the evaporator 3. Like a tube or a fixed throttle, it is set so that a predetermined pressure loss occurs when the refrigerant flows.

  Reference numeral 6 denotes internal heat that exchanges heat between the high-pressure refrigerant that has flowed out of the radiator 2 (the refrigerant before being depressurized by the ejector 4) and the low-pressure refrigerant that has flowed out of the gas-liquid separator 5 and sucked into the compressor 1. It is an exchanger. As a main part of the present invention, the flow of low-pressure refrigerant that flows out from the gas-liquid separator 5 and is sucked into the compressor 1 is interposed between the gas-liquid separator 5, the compressor 1, and the internal heat exchanger 6. A variable device (flow path variable means) 7 is arranged so that the path can be changed between a flow path passing through the internal heat exchanger 6 and a flow path not passing through the internal heat exchanger 6.

  FIG. 3 is a schematic cross-sectional view showing the structure of the variable device 7 in one embodiment of the present invention. The variable device 7 is provided with a gas-liquid separator communication path 7b through which the refrigerant from the gas-liquid separator 5 flows on the side surface side of the container 7a, and a compressor link that supplies the refrigerant to the compressor 1 on the top side of the container 7a. A passage 7c and an internal heat exchanger communication passage 7d for supplying the refrigerant to the compressor 1 via the internal heat exchanger 6 are provided on the ground side of the container 7a.

  Further, a float 71 adjusted to a predetermined density is provided in the container 7a, and the float 71 moves up and down depending on the density of the refrigerant flowing from the gas-liquid separator communication path 7b, so that the compressor flows directly to the compressor 1. The refrigerant flow path that flows to the communication path 7c and the internal heat exchanger communication path 7d that flows to the compressor 1 after passing through the internal heat exchanger 6 is made variable. The float 71 is a solid resin body, which is molded by adjusting a predetermined density by mixing an adjusting material in a resin material having an appropriate density.

  This variable unit 7 automatically adjusts the amount of refrigerant flowing into the internal heat exchanger 6 according to the density (temperature) of the refrigerant flowing from the gas-liquid separator 5, and determines the amount of heat exchange in the internal heat exchanger 6. The coefficient COP is automatically adjusted so as to keep it high.

  Next, the general operation of the ejector cycle (heat pump cycle) having the above-described configuration will be described. When the compressor 1 is started, the gas-phase refrigerant is sucked into the compressor 1 from the gas-liquid separator 5, and the compressed refrigerant is discharged to the radiator 2. The refrigerant cooled by the radiator 2 is decompressed and expanded substantially isentropically (adiabatically) at the nozzle 41 of the ejector 4 and sucks the refrigerant in the evaporator 3. Next, the refrigerant sucked from the evaporator 3 and the refrigerant blown out from the nozzle 41 are mixed in the mixing unit 4a and converted into static pressure in the diffuser unit 4b and returned to the gas-liquid separator 5. .

  That is, the jet flow (driving flow refrigerant) flowing out from the nozzle 41 itself decreases its flow velocity while sucking and accelerating the refrigerant from the evaporator 3. At this time, in the refrigerant outlet part of the mixing part 4a (refrigerant inlet part of the diffuser part 4b), mixing is performed so that the flow rate of the suction gas (suction flow refrigerant) sucked from the evaporator 3 and the flow rate of the driving flow refrigerant become substantially equal. Then, the mixed refrigerant flows into the diffuser portion 4b and increases the pressure while decreasing the flow velocity. On the other hand, since the refrigerant in the evaporator 3 is sucked by the ejector 4, the liquid phase refrigerant flows into the evaporator 3 from the gas-liquid separator 5, and the refrigerant flowing in absorbs heat from the air blown into the room. Evaporate.

  Next, features and operational effects of this embodiment will be described. First, a gas-liquid separator communication path 7b into which refrigerant from the gas-liquid separator 5 flows is provided on the side surface side of the container 7a, a compressor communication path 7c for supplying refrigerant to the compressor 1 is provided on the top side of the container 7a, and the container An internal heat exchanger communication path 7d for supplying a refrigerant to the compressor 1 via the internal heat exchanger 6 is provided on the ground side of 7a, and a float 71 having a predetermined density is provided in the container 7a. The variable unit 7 that changes the refrigerant flow path flowing in the compressor communication path 7c and the internal heat exchanger communication path 7d by the float 71 moving up and down depending on the density of the refrigerant flowing in from the communication path 7b, and the gas-liquid separator 5 It arrange | positions between the compressor 1 and the internal heat exchanger 6, and adjusts the heat exchange amount in the internal heat exchanger 6. FIG.

  FIG. 4 is a Mollier diagram in the heat pump cycle of FIG. In the present invention, chlorofluorocarbon, alternative chlorofluorocarbon, natural refrigerant or the like is used as the refrigerant, and the heat absorption in the evaporator 3 is in the condensation region. In such a heat pump cycle (refrigeration cycle), the refrigerant state at the outlet of the gas-liquid separator 5 is on the saturated vapor line, and the refrigerant density is uniquely determined by the refrigerant pressure (refrigerant evaporation temperature). Thus, the float 71 having a predetermined density is moved up and down in the container 7a so that the flow path passing through the internal heat exchanger 6 and the flow path not passing through the internal heat exchanger 6 are variable.

  More specifically, when the outlet pressure of the gas-liquid separator 5 is low (air temperature is low), the float 71 becomes heavier than the refrigerant and sinks in the container 7a, thereby blocking the internal heat exchanger communication path 7d. Thus, the refrigerant is directly introduced into the compressor 1 from the compressor communication path 7c. When the pressure at the outlet of the gas-liquid separator 5 is high (the air temperature is high), the float 71 is lighter than the refrigerant, and floats in the container 7a to close the compressor communication path 7c. It can be introduced into the internal heat exchanger 6 from the exchanger communication path 7d.

  FIG. 5 shows the relationship between the air temperature Tam on the upstream side of the air flow of the radiator 2 (front surface of the radiator 2) and the coefficient of performance of the cycle (COP = refrigeration capacity generated in the evaporator / compressor work). It is a numerical simulation result, a dashed-dotted line shows the case where a high pressure refrigerant | coolant and a low pressure refrigerant are always heat-exchanged, a broken line shows the case where it does not have an internal heat exchanger, and the continuous line has shown this embodiment. As apparent from FIG. 5, according to the present embodiment, the high-pressure refrigerant and the low-pressure are based on the air temperature Tam on the upstream side of the air flow of the radiator 2 (the front surface of the radiator 2), which is a physical quantity related to the high-pressure refrigerant. Since the amount of heat exchange with the refrigerant is variable, the coefficient of performance of the cycle can always be kept high.

  As a result, the amount of refrigerant flowing through the internal heat exchanger 6 is varied by the float 71 that rises and falls depending on the refrigerant density without using electrical control, and the amount of internal heat exchange according to the refrigerant pressure (refrigerant evaporation temperature). By adjusting to, a heat pump cycle (refrigeration cycle) that can always maintain a high coefficient of performance COP even when the air temperature Tam changes can be obtained.

(Other embodiments)
In the above-described embodiment, the variable device (flow path variable means) 7 of the present invention is applied to the ejector cycle. However, the variable device 7 of the present invention always has the refrigerant at the outlet of the evaporator or the refrigerant at the suction portion of the compressor. If it is in a saturated steam state, it can be applied to a heat pump cycle other than the ejector cycle. As a result, even in a heat pump cycle other than the ejector cycle, even if the air temperature Tam changes, a higher coefficient of performance COP can be ensured. Can be maintained. Further, in the above-described embodiment, the air conditioner is dedicated to cooling. However, the present invention is not limited to this, and the present invention is not limited to this. Can be applied.

It is a schematic diagram of the heat pump cycle using the ejector in one Embodiment of this invention. FIG. 2 is a schematic diagram of an ejector 4 applied to the heat pump cycle of FIG. It is a cross-sectional schematic diagram which shows the structure of the variable device 7 in one Embodiment of this invention. FIG. 2 is a Mollier diagram in the heat pump cycle of FIG. It is a relationship graph of the air temperature Tam which shows the effect of this invention, and a coefficient of performance COP.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Compressor 2 ... Radiator 3 ... Evaporator 4 ... Ejector 4a ... Mixing part (pressure | voltage rise part)
4b ... Diffuser section (boost section)
5 ... Gas-liquid separator 6 ... Internal heat exchanger 7 ... Variable device (flow path variable means)
7a ... Container 7b ... Gas-liquid separator communication passage 7c ... Compressor communication passage 7d ... Internal heat exchanger communication passage 41 ... Nozzle 71 ... Float

Claims (3)

A compressor (1) for sucking and compressing refrigerant;
A radiator (2) for cooling the refrigerant discharged from the compressor (1);
An evaporator (3) for evaporating the refrigerant and absorbing heat;
The pressure energy of the high-pressure refrigerant flowing out of the radiator (2) is converted into velocity energy to decompress and expand the refrigerant, and the evaporator (3) by the high-speed refrigerant flow injected from the nozzle (41). ), The vapor phase refrigerant evaporated is sucked, and the velocity energy is converted into pressure energy while mixing the refrigerant injected from the nozzle (41) and the refrigerant sucked from the evaporator (3), thereby adjusting the pressure of the refrigerant. An ejector (4) having a boosting section (4a, 4b) for boosting;
A gas-liquid separator (5) for separating the refrigerant into a gas-phase refrigerant and a liquid-phase refrigerant and storing the refrigerant;
An internal heat exchanger (6) for exchanging heat between the high-pressure refrigerant flowing out of the radiator (2) and the low-pressure refrigerant sucked into the compressor (1),
In the heat pump cycle in which the heat absorbed in the evaporator (3) is moved to the high temperature side by using the refrigerant in the condensation region,
A gas-liquid separator communication path (7b) into which the refrigerant from the gas-liquid separator (5) flows is provided on the side surface side of the container (7a), and the compressor (1) is provided on the top side of the container (7a). A compressor communication passage (7c) for supplying a refrigerant, and an internal heat exchanger connected to the compressor (1) via the internal heat exchanger (6) on the ground side of the container (7a). A passage (7d) is provided, and a float (71) having a predetermined density is provided in the container (7a). The float (71) moves up and down depending on the density of the refrigerant flowing from the gas-liquid separator communication passage (7b). Thus, the gas-liquid separator (5) and the compressor are provided with flow path variable means (7) for changing the flow path of the refrigerant flowing through the compressor communication path (7c) and the internal heat exchanger communication path (7d). (1) between the internal heat exchanger (6) and the internal heat exchanger (6). Heat pump cycle, characterized in that so as to adjust the heat exchange amount.   The heat pump cycle according to claim 1, wherein the flow path varying means (7) is applied to a heat pump cycle in which a refrigerant at an evaporator outlet is always in a saturated vapor state.   The heat pump cycle according to claim 1, wherein the flow path varying means (7) is applied to a heat pump cycle in which a refrigerant in a compressor suction portion is always in a saturated vapor state.

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