JPS62252870A - Method of controlling flow rate of refrigerant in refrigeration or heat pump cycle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION OBJECTS OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for controlling the flow rate of refrigerant in a refrigeration or heat bombardment.

(Prior Art) Conventionally, in a refrigeration cycle or a heat pump cycle, the refrigerant expansion process uses a throttle valve operation of an expansion valve (pressure reducing valve) or a throttle type automatic expansion valve in a dry cycle. Maeko can use either the liquid-filled method or the dry method, but
Whether it is manual or automatic, it is difficult to control the liquid volume to 1ill0, and there is a risk of liquid backing up because the liquid is full.The latter is a dry type, so control is good, but because it is dry, heat transfer efficiency is poor, and the evaporator is large. There is a drawback that the degree of superheating becomes large and the capacity decreases.

In the first place, the refrigerant jet 1 from the expansion valve is related to the differential pressure between high pressure and low pressure, and the differential pressure differs between summer and winter, and the Ri
l+ control is difficult due to differential pressure fluctuations and has the drawback of lacking reliability. For this purpose, a dry evaporator method is forced, and a throttle-type automatic expansion valve is used, which has poor heat transfer efficiency and controllability, and the throttle-type automatic expansion valve is also cost-effective.
- is high and large, and the cost of the control machine plate is also high.

(Problems to be Solved by the Invention) The conventional technology has various problems as mentioned above, and the current situation is that there is no complete control method for the amount of refrigerant in a wet evaporator that can achieve the best heat transfer effect. lko.

The present invention was made in view of this, and the evaporator is a dry type,
Regardless of the liquid type, the liquid refrigerant is adjusted to the optimum m according to the load.
The object of the present invention is to provide a method for eliminating the above-mentioned problems by controlling.

[Structure of the invention]

(Means for Solving the Problems) The refrigerant flow ffl t, II I11 method in a refrigeration or heat pump cycle of the present invention is configured by the following means in order to solve the above problems.

First Invention A volumetric two-phase flow 1a expander is connected to an induction machine, the rotation of the induction machine is electrically converted and controlled, and the induction machine is operated as a generator to generate power according to the control. The refrigerant flow rate during the expansion process is controlled in addition to reducing the amount of movement caused by recovery.

Second Invention A positive displacement two-phase flow expansion machine is connected to an induction machine, the rotation of the induction machine is electrically converted and controlled, the induction machine is operated as a generator to recover power, and the power is recovered. 1 along with reducing the reduction
, a positive displacement type in a liquid recirculation type cycle in which the refrigerant flow m in the IEIi expansion process is controlled to control the refrigerant liquid level in the low-pressure liquid receiver, while the refrigerant liquid in the separator is circulated between the load section and the refrigerant flow m. The liquid pump is connected to an electric motor, and the rotation of the electric motor is electrically converted and controlled, thereby controlling the refrigerant flow m.

Third Invention A positive displacement liquid in a liquid recirculation cycle in which refrigerant liquid is expanded by a throttle valve and introduced into a low-pressure liquid receiver, and the refrigerant liquid in the low-pressure liquid receiver is circulated between the load part and the refrigerant liquid. The pump was connected to 18 machines, and the electricity! The rotation of the JJ machine is electrically converted and controlled, thereby controlling the refrigerant flow rate.

(Function) By electrically controlling the induction machine in accordance with changes in load, etc. in the refrigeration or heat pump cycle, by controlling the rotation of the positive displacement expander and/or electric aI 11 connected to the induction machine, The refrigerant m supplied to the load can be controlled quickly and accurately, so that changes in the load can be immediately responded to, and power can be recovered as appropriate depending on the rotation.

(Example) FIG. 1 is a first practical example of carrying out the method of the present invention, in which 1 is a compressor, 2 is a condenser, 3a is an expansion rffXn of screw type two-phase flow, and 4 is an evaporator. , 7a is the expander 3a1. :
The induction machine 9a is a frequency converter that controls the induction machine 7a.

The refrigerant compressed by the compression 11 is cooled and condensed by the heat dissipation load 1G in the condenser 2, and flows through the liquid pipe 12 from the high-pressure liquid inlet boat 19 to the 1-shading machine 3a.
The induction machine 7a acts as a charging machine, recovers the energy that was lost as WIE in in the conventional throttle valve type as a power, flows from the discharge port 20 and passes through the communication pipe 13, flows into the evaporator 4 and performs an endothermic action;
Comply with the requirements of heat transfer 11. In addition, in the conventional technology, the liquid pipe 12
The refrigerant liquid expanded under reduced pressure by the expansion valve 3 of the liquid pipe 18 and was operated to flow into the heat generator 4.

The high-pressure liquid that has flowed into the expander 3a is turned into a low-pressure flash gas.
f! The applied pressure converts the pressure energy into recovered energy, and the directly connected induction 11i7a operates as a generator to convert the rotational energy into electricity, which is recovered by the commercial power source 25. The frequency converter 9a is an induction machine 7
It is interposed between the converter 7a and the commercial power supply 25, and adjusts the conversion frequency so that the synchronization speed of the induction machine 7a with respect to the conversion frequency becomes higher than the commercial frequency.

That is, the conversion frequency is detected by the controller 23 which issues a command to adjust the load, the temperature T of the refrigerant, the superheat degree T of the pressure fluid, etc. to a desired temperature in advance, and the control according to the load is performed by generating the induction motor 7a. As an iI machine, the power is recovered to the commercial power source 25 side, and the amount of refrigerant flowing through the l15r & valve 3a can be adjusted proportionally by the rotation speed.

FIG. 2 shows a second embodiment of the method of the present invention, which is a refrigeration cycle of a so-called liquid recirculation type cycle (liquid pump system). The A-cycle, which is the same circulation system as in FIG. 1, is combined with the B-cycle, which is a liquid pump type circulation system.

Components with the same reference numerals as those in FIG. 1 represent the same parts, so their explanation will be omitted.

5 is a low pressure liquid receiver, 6 is a positive displacement liquid pump, 8 is an electric motor, 9
b, 9c are frequency converters. The high-pressure refrigerant liquid flowing through the liquid pipe 12 flows into the expansion 113b through the high-pressure liquid inlet boat 19 and expands, and the induction machine 7b works as a generator to recover power, flows out from the gate outlet 20, and flows through the communication pipe 13. It flows into the low-pressure receiver 5 through. The controller 26 is for controlling the refrigerant liquid level in the low-pressure liquid receiver 5 at a constant level, and the frequency is controlled by the frequency converter 9b according to the rise and fall of the refrigerant liquid level to control the rotation of the induction machine 7b. Act to control.

In the Bυ cycle, the refrigerant liquid in the low-pressure liquid receiver 5 flows through the liquid pipe 1
4, flows into the positive displacement pump 6 from the inlet 21, flows through the outlet 22, is introduced into the evaporator 4, performs the evaporation action by the heat load 17, and then returns to the low-pressure liquid receiver 5 from the communication pipe 15. return. The positive displacement liquid pump 6 includes an electric n8 and a commercial 7 [2
Inverter control is performed by a frequency converter 9C inserted between the frequency converter 5 and the frequency converter 9C.

That is, the controller 27 is operated according to the temperature and pressure of the refrigerant or the temperature on the load side, the frequency is controlled by the frequency converter 9C, the rotation of the electric motor 8 is controlled, and the rotation of the positive displacement liquid pump 6 is controlled to perform evaporation. The temperature of the refrigerant liquid supplied to the vessel 4 is measured. If the positive displacement liquid pump is a screw type, it can guarantee a highly accurate discharge Φ equivalent to that of a flowmeter.

In addition, in the embodiment shown in FIG. 2, the low pressure liquid receiver 5
Since the control of the refrigerant liquid level and the heat load control in the evaporator 4 are controls that change proportionally to each other, the positive displacement liquid pump 6 and the expansion 1fi 3b are made coaxial, and the induction machine 7b and the electric motor 8 are are made common to the induction machine 7C, and therefore the controller 26, 27 and the frequency converter 9b, 9
c is also common to the adjuster 28 and frequency converter 9.
d and can be implemented as shown in FIG.

In addition, in the embodiments shown in FIGS. 1 to 3, frequency converters 9a to 9d are used, but the invention is not limited to such a one-sided inverter type, and induction motors 7a to 7C are used as frequency converters.
Any device may be used as long as it can electrically convert and control the rotation of the electric motor 1118, and a variable speed controller such as a Cerviras type or a twin chopper type can also be used.

〔Effect of the invention〕

According to the method of the present invention, even when operating a positive displacement two-phase flow expander, the maximum power generation can be increased to 17%, and the rotation of the expander and/or liquid pump can be reduced to 3%. I! Since the induction machine to be depleted is controlled by electrical conversion control, the liquid m of the supplied refrigerant can be automatically, quickly and accurately adjusted depending on the zero load, etc. Therefore, even in the case of a wet type, the refrigerant can be adjusted without causing liquid back up. Moreover, the power of the induction machine can also be reduced.

Control using an expansion valve (throttle valve) cannot perform the old control accurately, and since the throttle type automatic expansion valve is a dry system, the heat transfer efficiency is lower than that of the wet type. Accurate control of appropriate liquid volume is possible according to load fluctuations.

Furthermore, since a positive displacement two-phase flow expander is used as the expander, it is possible to achieve better results in terms of thermal efficiency than when using this as a blade wall turbine. That is,
In Fig. 4, when a blade wall turbine is used, the point is 0, and if an Ill valve is used, it can be made to the G point, but when a positive displacement two-phase flow expander is used, the gas-liquid mixture inside the expander is As a result, the expansion process of the high-pressure refrigerant liquid can be made similar to FD, and the power recovery is increased by GD compared to the case where a blade wall turbine is used. The amount of heat pumped up by the cycle can be increased by the amount iG-iD).

[Brief explanation of drawings]

1 to 3 are flow sheet diagrams of different embodiments for carrying out the method of the present invention, and FIG. 4 is a flow sheet diagram for explaining the effects of the method of the present invention.
-iG diagram. 3a, 3b... Expansion machine, 5... Low pressure liquid receiver, 6... Positive displacement liquid pump, 7a, 7b, 7c... Induction machine, 8...
- Electric motor, 9a, 9b, 9c, 9d... Frequency conversion controller as an electrical conversion controller. b Procedural Judgment No. 11 Sho 4 (Spontaneous) May 27, 1985 1, Case description 1988 Patent Application No. 94026 2, Title of invention Cold IR flow in refrigeration or heat pump cycle ■ Control method 3, Amendments made (Relationship with 't) Patent applicant Moegawa Seisakusho 4, agent 4-3-22 Shinjuku, Shinjuku-ku, Tokyo ('!2#, Building)
1Telephone 03-352-1561
5. Date of amendment order None 7. Contents of amendment (1) "Expansion valve 3aJ" at the end of page 7 of the specification is corrected to "expansion 1 expansion 3aJ." (2) Specification No. 8 From the first line to the second line of the page, next to ``It is proportionally adjustable.''
Of course, it is also possible to provide a plurality of a and perform a number control operation together. ” to join. aMay 270, 2005

Claims (5)

[Claims] (1) A positive displacement two-phase flow expander is connected to an induction machine, the rotation of the induction machine is electrically converted and controlled, and the induction machine is operated as a generator to recover power according to the control. A refrigerant flow rate control method in a refrigeration or heat pump cycle, characterized by controlling the refrigerant flow rate during an expansion process. (2) Claim 1, characterized in that a screw type two-phase flow expander is used as the volumetric two-phase flow expander.
A method for controlling the flow rate of refrigerant in a refrigeration or heat pump cycle as described in 1. (3) The expansion process is achieved by connecting a positive displacement two-phase flow expander to an induction machine, electrically converting and controlling the rotation of the induction machine, and operating the induction machine as a charger to recover power. A positive displacement liquid pump in a liquid recirculation cycle that controls the refrigerant flow rate in the low-pressure liquid receiver to control the refrigerant liquid level in the low-pressure liquid receiver, and circulates the refrigerant liquid in the low-pressure liquid receiver to and from the load section. 1. A refrigerant flow rate control method in a refrigeration or heat pump cycle, characterized in that the refrigerant flow rate is controlled by connecting to an electric motor, electrically converting and controlling the rotation of the electric motor, and thereby controlling the refrigerant flow rate. (4) A positive displacement liquid pump in a liquid recirculation cycle in which the refrigerant liquid is expanded by a throttle valve and introduced into a low-pressure liquid receiver, and the refrigerant liquid in the separator is circulated between the load section and the electric motor. A method for controlling a refrigerant flow rate in a refrigeration or heat pump cycle, characterized in that the rotation of the electric motor is electrically converted and controlled, thereby controlling the refrigerant flow rate. (5) Claims 1 to 4 characterized in that the positive displacement two-phase flow expander or positive displacement liquid pump is integrated with a canned induction machine that does not require a shaft sealing device. A refrigerant flow rate control method in any refrigeration or heat pump cycle.