JP2004286266A - Refrigeration device and heat pump type cooling and heating machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stable high-efficiency refrigeration cycle even in any temperature condition by improving load follow-up capability. <P>SOLUTION: A screw compressor 1, an air heat exchanger 2, a supercooler 8, an expansion valve 5 and a water heat exchanger 6 are sequentially connected by pipes; and a branch pipe 4 is installed branched from a part between the supercooler and the expansion valve and connected to an intermediated pressure chamber of the compressor after passing an electronic expansion valve 7 and the supercooler 8. The temperature of water supplied to a cool water load from the heat exchanger 6 is detected by a temperature sensor 10; the expansion valve 7 is controlled based on a signal from the temperature sensor to regulate the quantity of a branched refrigerant flowing to the supercooler 8. Thereby, the supercooling level of the refrigerant flowing through a main circuit is adjusted and cooling capability is controlled in line with the load. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a refrigerating apparatus or a heat pump type water heater for cooling or heating water and supplying the same to a load, and more particularly to an apparatus using a non-azeotropic mixed refrigerant such as R407C as a refrigerant.
[0002]
[Prior art]
As a refrigerating device such as an air conditioner having a conventional subcooler, for example, as shown in Patent Document 1, a subcooler is provided on the downstream side of a condenser, and the expansion device branches off from the downstream side of the subcooler. And a branch refrigerant pipe connected to an intermediate pressure chamber of a compressor after passing through a subcooler is known. An expansion valve is used as an expansion device provided in the branch refrigerant pipe. An electromagnetic valve is provided upstream of the expansion valve, and the main refrigerant is supercooled by flowing the branch refrigerant to a subcooler by opening and closing the electromagnetic valve. The cooling is secured greatly and the cooling capacity is improved. Further, as shown in Patent Document 2, for example, an electronic expansion valve is used as an expansion device of a branch refrigerant pipe, and also has a function of the electromagnetic valve.
[0003]
[Patent Document 1] JP-A-11-248264 (FIG. 2)
[Patent Document 2] JP-A-2001-296066 (FIG. 3)
[Problems to be solved by the invention]
In a non-azeotropic refrigerant mixture having a temperature gradient, the evaporator inlet refrigerant temperature becomes lower as the dryness in a two-layer state at the evaporator inlet becomes smaller at the same pressure. Therefore, in the cooling operation, the logarithmic average temperature difference between the water and the refrigerant increases, and the heat exchange performance improves. For this reason, it is possible to operate more efficiently if the degree of supercooling is secured in the condenser.However, in order to increase the degree of supercooling, it is necessary to increase the size of the condenser. Becomes larger. The temperature of the condensed and liquefied refrigerant does not drop below the heat source temperature. For this reason, a supercooler is provided to branch the refrigerant from the liquid pipe, and the degree of supercooling of the refrigerant flowing in the main circuit is increased by heat exchange between the refrigerant in which the branched refrigerant is decompressed and expanded and the refrigerant in the main circuit. Can be secured. Thus, lowering the evaporator inlet refrigerant temperature is an effective means for performing an efficient cycle operation in an air conditioner using a non-azeotropic mixed refrigerant.
[0004]
In the heating operation, the refrigerant branched from the liquid pipe and returning from the subcooler to the screw compressor intermediate pressure chamber merges with the refrigerant sucked from the main circuit into the screw compressor in the compression process, and condenses. Since the refrigerant flows into the water heat exchanger serving as a heat exchanger, the amount of the refrigerant flowing into the water heat exchanger increases, and the heating performance improves accordingly.
[0005]
However, in the related art, since the capacity of the supercooler and the capacity and the opening of the expansion valve are determined based on the temperature conditions defined in the standard, it is conceivable that the superheat degree cannot be maintained depending on the temperature conditions. Further, it is conceivable that the degree of supercooling of the refrigerant flowing through the main circuit becomes insufficient, and the refrigeration cycle becomes unstable. Therefore, the performance as an air conditioner fluctuates greatly depending on temperature conditions and is not stable. In addition, the supply of the branched refrigerant to the subcooler is controlled by being opened and closed by a shutoff valve such as an electromagnetic valve, so that the difference in capacity between the cooling and heating capacities becomes large, and the ability to follow the load fluctuation. If the temperature condition is bad and the capacity becomes significantly excessive with respect to the load, the air conditioner with the temperature control function will frequently start and stop, causing inefficient operation. No consideration was given to the conditions.
[0006]
In addition, if the heat exchange in the subcooler is insufficient, the branched refrigerant is not completely evaporated and is sent to the intermediate pressure chamber of the screw compressor, causing liquid compression or poor lubrication. Was.
[0007]
The object of the present invention is to improve the followability of the load while ensuring the reliability of the screw compressor under any temperature conditions, and to optimize the amount of the branch refrigerant supplied to the subcooler to achieve high performance and stability. An object of the present invention is to provide a refrigeration apparatus and a heat pump type water heater / heater capable of performing a refrigeration cycle operation.
[0008]
[Means for determining the task]
In order to achieve the above object, the present invention provides a screw compressor for compressing a refrigerant, an air heat exchanger for condensing and liquefying the refrigerant, a supercooler for further cooling the condensed refrigerant, and an expansion device for expanding the condensed refrigerant. And a refrigeration apparatus including a water heat exchanger for exchanging heat between the expanded refrigerant and water supplied to a chilled water load, wherein the compressor branches off from a downstream side of the subcooler and passes through the subcooler. A branch refrigerant pipe connected to the intermediate pressure chamber side, an electronic expansion valve provided on the upstream side of the subcooler in the branch refrigerant pipe, and the electronic expansion valve is supplied from the water heat exchanger to the cold water load. And control means for controlling based on the temperature of the water, and the refrigerant is a non-azeotropic mixed refrigerant.
[0009]
Other features of the present invention include a capacity-controlled screw compressor for compressing refrigerant gas, an air heat exchanger for exchanging heat between the refrigerant and air to condense and liquefy the refrigerant, and a supercooler for further cooling the condensed and liquefied refrigerant. A refrigerating apparatus configured by connecting a pipe to an expansion device for decompressing and expanding the condensed and liquefied refrigerant and a water heat exchanger for evaporating and evaporating the refrigerant by exchanging heat with water supplied to the chilled water load. A branch refrigerant pipe branched from the main refrigerant pipe between the compressor and the expansion valve, and connected to the intermediate pressure chamber side of the compressor after passing through the electronic expansion valve and the supercooler; A temperature sensor for detecting the temperature of water supplied to the load, and control means for controlling the electronic expansion valve based on a signal from the temperature sensor to adjust the amount of refrigerant flowing to the supercooler, As non-azeotropic refrigerant There to be used.
[0010]
Here, it is preferable that the control means controls the degree of superheating of the refrigerant flowing through the branch refrigerant pipe at the subcooler outlet by controlling the electronic expansion valve.
[0011]
Further, the control unit may control the electronic expansion valve to control the degree of supercooling of the refrigerant flowing through the main refrigerant pipe at the supercooler outlet, and control the cooling capacity according to the load. .
[0012]
Still another feature of the present invention is a capacity control type compressor for compressing a refrigerant gas, an air heat exchanger for exchanging heat between the refrigerant and air to condense and liquefy the refrigerant, and a supercooler for further cooling the condensed and liquefied refrigerant. An expansion device that decompresses and expands the condensed and liquefied refrigerant, and a refrigeration device that is connected by pipe connection to a heat exchanger that evaporates the refrigerant that exchanges heat with the load. A branch refrigerant pipe branched from the main refrigerant pipe and connected to the intermediate pressure chamber side of the compressor after passing through the electronic expansion valve and the subcooler, and a suction pressure sensor for detecting a pressure of the refrigerant sucked into the compressor A temperature sensor for detecting a refrigerant temperature at a subcooler outlet side of the branch refrigerant pipe, and a temperature detected by the temperature sensor converging to a superheat degree region set in advance corresponding to the pressure of the intermediate pressure chamber. So that the electronic expansion In that it comprises a control means for controlling the.
[0013]
Here, there is provided a discharge pressure sensor for detecting a discharge pressure of the compressor, and a temperature sensor for detecting a liquid refrigerant temperature of a main refrigerant pipe on a subcooler outlet side, and a liquid refrigerant on a main refrigerant pipe on a subcooler outlet side. However, the degree of opening of the electronic expansion valve may be adjusted so that the degree of supercooling becomes equal to or higher than a preset degree of supercooling in accordance with the discharge pressure.
[0014]
When the compressor performs the partial load operation, the electronic expansion valve is fully closed, and when the compressor reaches 100% operation and further cooling capacity is required, the opening degree of the electronic expansion valve is adjusted. It is preferable to perform control so as to adjust the flow rate of the branch refrigerant supplied to the subcooler.
[0015]
Still another feature of the present invention is a screw compressor for compressing the refrigerant gas, an air heat exchanger for exchanging heat between the refrigerant and the air, an expansion device for decompressing and expanding the condensed and liquefied refrigerant, and a cold / hot water load. A water heat exchanger for exchanging heat between water and refrigerant, a refrigerant amount regulator for adjusting the amount of refrigerant circulating in the system, a four-way switching valve connected to the refrigerant discharge side of the screw compressor to switch the refrigerant circulation direction, In a heat pump type water heater with water, a non-azeotropic mixed refrigerant is used as the refrigerant, and a branch refrigerant pipe that branches a part of the condensed and liquefied refrigerant and sends it to the intermediate pressure chamber side of the screw compressor. An electronic expansion valve provided in the branch refrigerant pipe to decompress and expand the branch refrigerant; and a supercooler for exchanging heat between the condensed and liquefied refrigerant and the expanded branch refrigerant. Detecting the temperature of the cold and hot water in the water heat exchanger supplied to the, by controlling the flow rate of the branch refrigerant pipe flowing to the subcooler by the electronic expansion valve according to this temperature, cooling and cooling according to the load This is to control the heating capacity.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
A specific embodiment of the present invention will be described with reference to FIGS. FIGS. 1 and 2 are refrigeration cycle system diagrams each showing an embodiment in which the present invention is applied to a refrigeration apparatus as an air conditioner or a heat pump chiller / heater. The arrows in the figure indicate the flow direction of the refrigerant.
[0017]
In FIG. 1, 1 is a screw compressor, 2 is an air heat exchanger, 3 is a main refrigerant pipe, 4 is a branch pipe (branch refrigerant pipe) that branches a part of the liquid refrigerant flowing through the main refrigerant pipe 3, and 5 is expansion. A valve, 6 is a water heat exchanger, 7 is an electronic expansion valve for branch refrigerant provided in the branch pipe 4, and 8 is a subcooler. The branch pipe 4 connects the main refrigerant pipe 3 between the subcooler 8 and the expansion valve 5 and the intermediate pressure chamber 1b of the screw compressor 1, and the subcooler 8 is provided in the middle thereof. .
[0018]
The high-temperature and high-pressure gas refrigerant discharged from the screw compressor 1 is heat-exchanged with air by the air heat exchanger 2 to condense and liquefy, and the supercooler 8 provided in the pipe 3 downstream of the air heat exchanger 2 After being supercooled, the pressure is reduced and expanded by the expansion valve 5 and flows into the water heat exchanger 6. The water heat exchanger 6 exchanges heat with water 9 supplied to a load such as a fan coil unit, evaporates, becomes gas refrigerant again, and is sucked into the screw compressor 1 from the suction port 1 a of the screw compressor 1. (Hereinafter, the refrigerant circulating in the main circuit of the refrigeration cycle will be abbreviated as the main refrigerant.)
Among the main refrigerant, the liquid refrigerant branched to the branch pipe 4 is decompressed and expanded by the electronic expansion valve 7, exchanges heat with the main refrigerant in the subcooler 8, evaporates to a gas refrigerant, and the intermediate refrigerant of the screw compressor 1. It is sent to the pressure chamber 1b, mixed with the main refrigerant, compressed again by the compressor 1, and discharged from its discharge port 1c.
[0019]
The screw compressor 1 has a capacity control function (a rotation speed control function by an inverter or the like or a mechanical capacity control function), and the capacity is controlled by the water outlet temperature of the water heat exchanger 6 detected by the water outlet temperature sensor 10. Drive. When the screw compressor 1 performs the partial load operation, the electronic expansion valve 7 is fully closed, and when the screw compressor 1 reaches 100% operation and further cooling capacity is required, the opening degree of the electronic expansion valve is set. The adjustment is performed, and the flow rate of the branch refrigerant supplied to the subcooler 8 is adjusted. As a result, it is possible to secure a large degree of subcooling of the main refrigerant, increase the enthalpy difference and the logarithmic average temperature difference between water and the refrigerant, and control the cooling capacity. As a result, the capacity control width of the supercooler is added to the capacity control width of the screw compressor 1, and the capacity control width of the air conditioner is expanded, so that more accurate water temperature control becomes possible. Become.
[0020]
The embodiment of FIG. 2 has the same basic structure as that of FIG. 1, but is further provided with a suction pressure sensor 11, a discharge pressure sensor 12, and a temperature sensor provided at a subcooler main circuit outlet liquid pipe. 13, a temperature sensor 14 for measuring the temperature of the outlet of the subcooler 8 of the branch pipe 4 is provided, and the controller 15 controls the opening of the electronic expansion valve 7 provided in the branch pipe 4 based on the temperature information. Things.
[0021]
The suction refrigerant pressure of the screw compressor 1 is detected by a suction pressure sensor 11, and the detected suction pressure value is input to the controller 15 and is converted into the pressure of the screw compressor intermediate pressure chamber in the controller 15. The operation pressure of the intermediate chamber is defined by a calculation formula defined by the suction pressure of the screw compressor and the position of the intermediate pressure chamber inlet port 1b. The subcooler branch refrigerant outlet temperature is detected by a branch pipe outlet temperature sensor 14 provided on the downstream side of the subcooler of the branch pipe 4, input to the controller 15, and set in advance by the superheater corresponding to the intermediate pressure chamber. The degree of opening of the electronic expansion valve 7 is adjusted so as to converge to the degree range. Thus, the superheat degree of the refrigerant flowing in the intermediate pressure chamber 1b of the screw compressor can be stabilized under any temperature conditions, and the reliability of the compressor can be improved.
[0022]
The discharge gas refrigerant pressure of the screw compressor 1 is detected by the discharge pressure sensor 12, and the temperature of the liquid refrigerant flowing through the main refrigerant pipe at the outlet of the subcooler is detected by the temperature sensor 13 and input to the controller 15, respectively. Thereby, the degree of opening of the electronic expansion valve 7 can be adjusted so that the degree of supercooling becomes equal to or more than a preset degree of supercooling corresponding to the discharge pressure, whereby the main refrigerant pipe 3 flows under any temperature conditions. The degree of supercooling of the liquid refrigerant can be stabilized, and the cooling capacity can be stabilized. At this time, the degree of superheat of the subcooler outlet refrigerant temperature of the branch pipe 4 is also controlled.
[0023]
According to this embodiment, a stable refrigeration cycle can be obtained by using the electronic expansion valve 7 as the expansion device for the branch refrigerant provided in the branch pipe 4, and as a refrigeration device such as an air conditioner. It is also possible to expand the capacity control width of the above, and when used as a heat pump type chiller / heater, high precision water temperature control becomes possible.
[0024]
【The invention's effect】
According to the present invention, since the expansion device on the branch refrigerant side is an electronic expansion valve, it is possible to optimally adjust the amount of branch refrigerant supplied to the subcooler in accordance with the load, and thereby, as an air conditioner The capacity control width can be expanded. In particular, the capacity control width can be further expanded by using a capacity control type compressor together.
[0025]
Further, the amount of heat exchange in the supercooler can be stabilized under any temperature conditions, the degree of supercooling in the main refrigerant pipe can be stabilized, and a stable refrigeration cycle can be operated.
[Brief description of the drawings]
FIG. 1 is a refrigeration cycle system diagram showing one embodiment of the present invention.
FIG. 2 is a refrigeration cycle system diagram showing another embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Screw compressor, 1a ... Compressor suction port, 1b ... Intermediate pressure chamber inlet port, 1c ... Compressor discharge port, 2 ... Air heat exchanger, 3 ... Main refrigerant pipe, 4 ... Branch pipe (branch refrigerant pipe) 5, expansion valve, 6: water heat exchanger, 7: electronic expansion valve for branch refrigerant, 8: subcooler, 9: water, 10: water outlet temperature sensor, 11: suction pressure sensor, 12: discharge pressure Sensors, 13, 14: temperature sensor, 15: controller (control means).

Claims (8)

A screw compressor that compresses the refrigerant, an air heat exchanger that condenses and liquefies the refrigerant, a supercooler that further cools the condensed refrigerant, an expansion device that expands the condensed refrigerant, and the expanded refrigerant and the chilled water load In a refrigeration apparatus having a water heat exchanger for exchanging heat with supplied water,
A branch refrigerant pipe branched from the downstream side of the subcooler and connected to the intermediate pressure chamber side of the compressor after passing through the subcooler,
An electronic expansion valve provided upstream of the subcooler in the branch refrigerant pipe;
Control means for controlling the electronic expansion valve based on the temperature of water supplied from the water heat exchanger to the chilled water load, and the refrigerant is a non-azeotropic mixed refrigerant. A capacity control compressor that compresses refrigerant gas, an air heat exchanger that exchanges heat between refrigerant and air to condense and liquefy the refrigerant, a supercooler that further cools the condensed and liquefied refrigerant, and decompresses and decompresses the condensed and liquefied refrigerant. In an expansion device to expand, and a refrigerating device configured by pipe connection of a water heat exchanger that exchanges heat with water supplied to a chilled water load and evaporates and vaporizes a refrigerant,
A branch refrigerant pipe branched from the main refrigerant pipe between the subcooler and the expansion valve, and passing through the electronic expansion valve and the subcooler, and connected to the intermediate pressure chamber side of the compressor,
A temperature sensor for detecting the temperature of water supplied from the water heat exchanger to the chilled water load,
Control means for controlling the electronic expansion valve based on the signal from the temperature sensor to adjust the amount of refrigerant flowing to the subcooler,
A refrigeration apparatus using a non-azeotropic mixed refrigerant as the refrigerant. 3. The refrigeration apparatus according to claim 1, wherein the control unit controls the degree of superheating of the refrigerant flowing through the branch refrigerant pipe at a subcooler outlet by controlling the electronic expansion valve. 4. 3. The control device according to claim 1, wherein the control unit controls the electronic expansion valve to control the degree of subcooling of the refrigerant flowing through the main refrigerant pipe at the supercooler outlet, and controls the cooling capacity according to the load. A refrigeration apparatus characterized by the above-mentioned. A capacity control compressor that compresses refrigerant gas, an air heat exchanger that exchanges heat between refrigerant and air to condense and liquefy the refrigerant, a supercooler that further cools the condensed and liquefied refrigerant, and decompresses and decompresses the condensed and liquefied refrigerant. In a refrigerating device configured by pipe connection of an expansion device for expanding, and a heat exchanger for evaporating a refrigerant for heat exchange with a load,
A branch refrigerant pipe branched from the main refrigerant pipe between the subcooler and the expansion valve, and passing through the electronic expansion valve and the subcooler, and connected to the intermediate pressure chamber side of the compressor,
A suction pressure sensor for detecting a pressure of the suction refrigerant to the compressor,
A temperature sensor for detecting a refrigerant temperature on the subcooler outlet side of the branch refrigerant pipe,
Control means for controlling the electronic expansion valve so that the temperature detected by the temperature sensor converges to a degree of superheat set in advance corresponding to the pressure of the intermediate pressure chamber. Refrigeration equipment. In Claim 5, a discharge pressure sensor for detecting a discharge pressure of the compressor, and a temperature sensor for detecting a liquid refrigerant temperature of a main refrigerant pipe on a subcooler outlet side, wherein a main refrigerant pipe on a subcooler outlet side is provided. A refrigerating apparatus, wherein the opening degree of the electronic expansion valve is adjusted so that the liquid refrigerant has a degree of supercooling set in advance according to a discharge pressure. The electronic expansion valve according to claim 2 or 5, wherein the electronic expansion valve is fully closed when the compressor performs a partial load operation, and when the compressor reaches 100% operation and further cooling capacity is required. A refrigerating apparatus that adjusts the opening degree of the refrigerant to adjust the flow rate of the branch refrigerant supplied to the subcooler. Screw compressor for compressing refrigerant gas, air heat exchanger for exchanging heat between refrigerant and air, expansion device for decompressing and expanding condensed and liquefied refrigerant, heat exchange between water and refrigerant supplied to cold / hot water load A water heat exchanger, a refrigerant amount regulator for adjusting the amount of refrigerant circulating in the system, and a four-way switching valve connected to the refrigerant discharge side of the screw compressor to switch the refrigerant circulation direction. ,
A branch refrigerant pipe that uses a non-azeotropic mixed refrigerant as the refrigerant, and branches a part of the condensed and liquefied refrigerant to an intermediate pressure chamber of the screw compressor,
An electronic expansion valve provided in the branch refrigerant pipe to decompress and expand the branch refrigerant;
A supercooler that performs heat exchange between the condensed and liquefied refrigerant and the branched refrigerant after expansion,
By detecting the temperature of the cold and hot water in the water heat exchanger supplied to the cold and hot water load, and controlling the flow rate of the branch refrigerant pipe flowing to the subcooler by the electronic expansion valve in accordance with this temperature, A heat pump type water cooler / heater characterized by controlling the cooling and heating capacity.

Images