JP4518544B2 - Operation control device for steam compression refrigerator - Google Patents

Description

The present invention relates to an ice heat storage system using a steam compression refrigerator as a cooling source, and a steam for the purpose of eliminating problems caused by the return of high-temperature cold water in the heat storage tank and the piping path to the evaporator at the start of the heat storage operation. The present invention relates to an operation control device for a compression refrigerator.

The purpose of the heat storage system is to use inexpensive late-night power and reduce running costs. The heat storage operation of the refrigerator is performed during a limited time zone in which a midnight power rate is set, and the necessary amount of heat is stored during that time. For this reason, it is desired that the cooling heat source of the heat storage system has a short time to reach the rated capacity. Moreover, since the capacity | capacitance of the conveyance facility of the ice thermal storage system which flows ice slurry liquid is small compared with water conveyance, it is desired to produce ice slurry liquid as soon as possible.
Conventionally, an ice heat storage system using a steam compression refrigerator as a cold source has a configuration as shown in FIG. 6 disclosed in Japanese Patent Application Laid-Open No. 2002-257385. To explain this, reference numeral 1 denotes a steam compression refrigerator, which includes an evaporator 1a, a compressor 1b, and a condenser 1c. The evaporator 1a guides the circulating water 3 from the ice heat storage tank 2 and evaporates a part of the circulating water 3 while maintaining the low pressure by the operation of the compressor 1b. The compressor 1b pressurizes the water vapor introduced from the evaporator 1a under predetermined conditions. The condenser 1c introduces water vapor that has been pressurized by the compressor 1b and has reached a high temperature, and cools it with cooling water 5 introduced from a cooling tower 4 installed outside to condense.
Here, the ice heat storage tank 2, the evaporator 1a of the steam compression refrigerator 1, the ice slurry pump 6 and the connecting pipe connecting them are filled with tap water as makeup water.
The cooling tower 4 is ancillary equipment of the steam compressor refrigerator 1 and introduces makeup water. The cooling water 5 led from the condenser 1c is sent by the cooling water pump 1d, and a part thereof is evaporated to the atmosphere. At the same time, a part thereof is discharged as blow water, and the makeup water is added to the cooling water 5 and introduced into the condenser 1c. The cooling tower 4 has a function of discharging the heat of the cooling water whose temperature has been increased by condensing water vapor in the condenser 1c to the atmosphere by the heat of vaporization accompanying the evaporation of the cooling water.
An ice heat storage tank 2 stores the low-temperature ice slurry taken out from the evaporator 1a via the ice slurry pump 6. In the ice heat storage tank 2, ice melting water 2a is guided from the heat exchanger 7 for cooling and heating described later, and the ice melting action of the low-temperature ice slurry is performed, so that ice and melting water, that is, cold water are mixed. The cold water is pumped to the cold heat exchanger 7 by the deicing water pump 2b. The cold heat exchanger 7 circulates cold water by a cold water pump 7a to a cooling load (not disclosed) as a so-called heat extraction cycle.
By the way, the steam compression refrigerator 1 is a refrigerator in which the evaporator 1a uses water that does not pass through a heat exchanger as a refrigerant. That is, the water that is the refrigerant of the steam compression refrigerator 1 is directly connected to the load side through the inside of the evaporator 1a and the pipe, and all of the water including the water in the ice heat storage tank 2 can be said to be a refrigerant. In order to start the water vapor compression refrigerator 1 to a desired rated operation state, it takes time until the temperature of the cold water introduced into the evaporator 1a is lowered to some extent. Until the temperature of the heat storage tank 2 and the entire water in the piping was lowered, the circulation of water had to be repeated between the evaporator 1a and the ice heat storage tank 2.
Japanese Patent Laid-Open No. 2002-257385

However, the evaporator 1a of the steam compression refrigerator 1 that generates the ice slurry liquid has a structure that takes into account the latent heat cooling that accompanies the phase change from the water of the heating medium to ice, and in the cooling that does not generate the ice slurry liquid. The evaporation area is small and it is difficult to output the rated capacity stably. Further, in a state where the temperature of the cold water fed to the evaporator 1a is high, for example, 8 ° C. or higher, the pressure in the evaporator 1a is high and the compressor 1b cannot be raised to the rated rotation. Therefore, the efficiency outside the rated conditions generally decreases.

The inside of the evaporator 1a of the steam compression refrigerator 1 has a vacuum pressure, and a part of the fed cold water evaporates to become water vapor, and the air dissolved in the cold water precipitates and moves to the gas phase side. . At this time, the water surface of the evaporator 1a is in a boiling state, and the resulting water droplets wet the demister on the wall surface of the gas phase part and the evaporator 1a and freeze at these parts during the ice making operation. The wall surface and the demister of the evaporator 1a are provided with a measure for dropping the frozen ice. However, when the ice grows quickly, the water surface, that is, the evaporation surface or the demister is closed, and water vapor is sucked into the evaporator 1a. It becomes a cause to prevent. The degree of splash becomes more prominent as the temperature of cold water fed into the evaporator 1a is higher and the amount of dissolved air is larger.

Due to the above problems, the start-up operation at the start of the heat storage operation of the steam compression refrigerator 1, that is, the operation until the cold water is cooled to the cold water temperature at which ice can be made becomes less than the rated capacity, and the efficiency also decreases. Moreover, the cause of the freezing failure in the evaporator 1a at the time of ice making operation is also caused.
Therefore, the present invention has been made to solve the above-described problem, and relates to an ice heat storage system using the steam compression refrigerator 1 as a cold heat source, and a rise time from the start of the refrigerator to the ice making operation (rated operation). The purpose is to suppress the splashed water in the evaporator 1a at the time of start-up and to reduce energy loss.

The operation control apparatus for a steam compression refrigerator according to the present invention prevents the hot cold water in the heat storage tank from being sent to the evaporator during the start-up operation of the steam compression refrigerator at the start of heat storage, The cold heat or ice slurry liquid in the forward pipe manufactured by the refrigerator is introduced into the return cold water in the return pipe, the temperature of the cold water in the return pipe is lowered, and the time to start the ice making operation of the steam compression refrigerator is shortened This is intended to be achieved, and consists of the following configurations and means.

That is, according to the first aspect of the present invention, the ice evaporator deployed prevention demister and a stirrer water droplet scattering, and vapor compression refrigeration machine comprising the condenser and the compressor, the ice slurry generated in the preceding Symbol evaporator a forward pipe that Nagareoku in the thermal storage tank, before and return pipe for Nagareoku before Symbol evaporator cold water from Kikori heat storage tank, start the slurry pump disposed in the forward pipe, distribution to the return pipe A control valve that detects the water level of the ice slurry liquid in the evaporator and controls the valve opening by a water level meter, and an ice slurry temperature that is disposed in the forward pipe and measures the temperature and flow rate of the ice slurry liquid Bypass control for controlling the valve opening with a measured value of a chilled water thermometer disposed in the return pipe and interposed in a bypass pipe connected between the flowmeter and the return pipe and the return pipe A valve and a measured value of the cold water thermometer disposed in the return pipe A control valve for controlling the valve opening, characterized in that and a chilled water pump for controlling the cold water to flow in or out to the connected and the ice heat storage tank in a bypass passage arranged in parallel to the bypass pipe.

Since the operation control apparatus of the steam compression refrigerator according to the present invention has the above-described configuration, the following effects can be obtained.
That is, since the water droplet scattering prevention demister and stirrer are provided in the evaporator, it is possible to prevent water droplets of cold water and ice making water from splashing to the compressor side due to evaporation of cold water, etc., and also the effect of preventing ice formation between ice There is. In addition, a control valve is provided in the return pipe, and the water level of the ice slurry stored in the evaporator of the steam compression refrigerator is detected by a water level meter, and the valve opening of the control valve is determined by this detection signal. The level of the ice slurry liquid can be controlled, and the opening degree of the valve can be controlled by the measured value of the cold water thermometer that detects the temperature of the cold water flowing in the return pipe. All of the ice slurry liquid fed from the slurry pump is sent from the return pipe to the evaporator via the bypass control valve connected to the bypass pipe and is not sent to the ice heat storage tank. The ice slurry liquid or cold water in the container can be maintained at a low temperature, and there is an effect that the start-up of the steam compression refrigerator can be operated quickly. When the bypass control valve is fully open, that is, when the temperature of the chilled water thermometer shows a high value, the chilled water pump is operated as necessary to squeeze the control valve to perform full bypass, and the flow rate of chilled water flowing into and out of the ice heat storage tank There is an effect that the balance of the balance can be compensated.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of an operation control apparatus for a steam compression refrigerator according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a structural layout diagram showing one example in an embodiment of an operation control apparatus for a steam compression refrigerator according to the present invention.

A steam compression refrigerator 8 for producing ice slurry is composed of an evaporator 8a, a condenser 8b, and a compressor 8c. A water droplet scattering prevention demister 9 is provided in the evaporator 8a to constitute a so-called Bessel type evaporator 8a. The water droplet scattering preventing demister 9 prevents water droplets of cold water or ice-making water from splashing toward the compressor 8c due to evaporation of cold water from the evaporator 8a.

Reference numeral 10 denotes a stirrer, which is inserted into the evaporator 8a and has a function of preventing ice formation between ices and uniforming ice slurry by stirring the stored cold water. Reference numeral 11 denotes a blade of the compressor 8c.

A forward pipe 12 is connected or connected between the outlet side of the evaporator 8 a of the steam compression refrigerator 8 and the ice heat storage tank 13. Then, the ice slurry liquid 8d generated by the evaporator 8a is sent to the ice heat storage tank 13. A slurry pump 14 is provided in the forward pipe 12 and includes a flow meter 14a. The inverter 14b controls the flow rate of the ice slurry liquid 8d to be fed into the forward pipe 12. An ice slurry thermometer 15 measures the temperature of the ice slurry liquid 8d in the forward pipe 12 fed from the evaporator 8b, that is, the cold water outlet temperature.

A return pipe 16 is connected or connected between the ice heat storage tank 13 and the inlet side of the evaporator 8a of the steam compression refrigerator 8. Further, the return pipe 16 is provided with a control valve 17, and the water level level meter 17a detects the water level of the ice slurry liquid 8d stored in the evaporator 8a of the steam compression refrigerator 8, and this detection signal. Thus, the valve opening degree of the control valve 17 is controlled, and the liquid level of the ice slurry liquid 8d is controlled. A bypass pipe 18 is connected or piped between the path of the forward pipe 12 and the path of the return pipe 16.

Reference numeral 19 denotes a bypass control valve, which is disposed in the path of the bypass pipe 18, and the opening degree of the valve is controlled by a measured value of a cold water thermometer 19a that detects the temperature of the cold water flowing through the return pipe 16. The chilled water thermometer 19a is a chilled water in the return pipe 16 in which the cold water sent from the ice heat storage tank 13 of the return pipe 16 and the ice slurry liquid 8d sent from the bypass pipe 18 are mixed. It is arranged at a position where the temperature of can be detected.

An ice heat storage tank cold water thermometer 13a is disposed on the return pipe 16 on the outlet side of the ice heat storage tank 13 and detects the temperature of the cold water flowing out of the ice heat storage tank 13.

Next, the operation | movement etc. based on embodiment of the operation control apparatus of the water vapor | steam compression refrigerator which concerns on this invention mentioned above are clarified.

During operation of the steam compression refrigerator 8, regardless of the temperature state of the ice heat storage tank 13, by controlling the flow rate of the bypass pipe 18, the temperature of the cold water at the start of the steam compression refrigerator 8 is set to a set value or less. The purpose is to intend stable operation of the steam compression refrigerator 8.
First, a vacuum pump (not shown) provided separately in the present system is started. For example, a vacuum system (not shown) is started at a saturated steam temperature of about 24 (° C.) and a vacuum pressure of 3.0 (KPa). . Then, the slurry pump 14 is started, the flow value of the ice slurry liquid 8d is calculated from the measured value from the flow meter 14a, and the inverter 14b is operated to perform constant flow control. On the other hand, the water level of the ice slurry liquid 8d stored in the evaporator 8d is detected by the water level meter 17a, the valve opening degree of the control valve 17 is controlled by this detection signal, and the water level control is started.

Thus, the water vapor compression refrigerator 8 is started, and when the measured value by the cold water thermometer 19a is, for example, a set value of 5 (° C.) or more, the bypass control valve 19 starts the valve opening operation. Then, the ice slurry liquid 8 d that flows in the forward pipe 12 is drawn into the path of the bypass pipe 18 and introduced into the return pipe 16.

When the measured value of the cold water thermometer 19a, that is, the cold water temperature after bypass control of the ice slurry liquid 8d by the bypass control valve 19 is, for example, 8 (° C.) or more, the compressor of the steam compression refrigerator 8 is The rotation speed is limited to 35 (Hz), for example, and when the measured value by the cold water thermometer 19a becomes 8 (° C.) or less, the rotation speed of the steam compression refrigerator 8 is increased to, for example, 60 (Hz). .
Further, when the measured value by the chilled water thermometer 19a, that is, the chilled water temperature becomes, for example, 6 (° C.) or less, the steam compression refrigerator 8 rotates in the steady operation region, for example, to a rotational speed of 70 (Hz). Raise.

The opening degree of the bypass control valve 19 is adjusted so that the cold water inlet temperature in the return pipe 16, that is, the measured value of the cold water thermometer 19a becomes a set value, for example, 5 (° C.).
When the bypass control valve 19 is ON-OFF controlled, the bypass control valve 19 is closed when the temperature of the chilled water flowing through the return pipe 16 is a set value, that is, 5 (° C.) or less.

And when the valve opening degree of the bypass control valve 19 becomes the minimum opening degree, the valve of the bypass control valve 19 is closed, and the ice slurry liquid 8d or the cold water flows into the return pipe 16 from the bypass pipe 18. Stop. The minimum opening is a valve opening set in advance so as not to block the ice slurry.

Moreover, when the measured value of the chilled water by the hot water thermometer 19a, that is, the chilled water temperature value in the return pipe 16 is 5 (° C.) or more, it is necessary to quickly reduce the temperature of the chilled water during sensible heat cooling. . Then, when the temperature of the ice slurry liquid 8d by the ice slurry thermometer 15, that is, the cold water outlet temperature is 0 (° C.) or less, which is the time when the ice slurry liquid is produced, ice water is added to the cold water on the inlet side of the evaporator 8a. The steam compression refrigerator 8 is controlled to operate at a temperature value that does not remain, for example, 2 (° C.) or more. Furthermore, for example, when the chilled water inlet temperature changes greatly, the chilled water outlet temperature fluctuates accordingly, the pressure in the evaporator 8a fluctuates, and the operation of the steam compression refrigerator 8 becomes unstable so that ice can be prevented. It is important to terminate the control in a state where there is little difference between the cold water temperature in the heat storage tank 13 and the cold water inlet temperature after the valve opening degree is controlled by the bypass control valve 19.

Next, FIG. 2 is a characteristic of the operation control of the steam compression refrigerator 8 according to the present invention and shows the temperature (° C.) of the cold water flowing in the forward pipe 12 or the return pipe 16 with respect to the operation time (min). The characteristics of the bypass control valve 19 according to the operation will be described.

FIG. 2 shows the chilled water inlet / outlet temperatures in the operation with the bypass control and the operation without the bypass control. The cold water temperature setting after bypass of the bypass control was set to 5 (° C.).
In addition, the characteristic line in a graph shows each cold water temperature (degreeC) with respect to the operation time (min) from a steam compression refrigerator start,
a is a chilled water outlet temperature characteristic line when the bypass control is not performed b is a chilled water outlet temperature characteristic line when the bypass control is performed c is a chilled water inlet temperature characteristic line after mixing when the bypass control is performed It is a cold water inlet temperature characteristic line before mixing at the time of performing.

According to this verification, the operation in which the bypass control was performed had a time 0 T for reaching the chilled water outlet temperature T of about 100 (min) shorter than the operation in which the bypass control was not performed. That is, the time from the start of operation to the ice making operation state has been shortened, and the difference in operation efficiency between the sensible heat operation (water heat storage operation) and the latent heat operation (ice heat storage operation) corresponding to this shortening is energy saving. .

As a result of the above verification, since the ice slurry liquid 8d starts to be produced when the cold water inlet temperature is about 5 (° C.) or less, when the cold water temperature of the ice heat storage tank 13 is 5 (° C.) or more, sensible heat cooling occurs. The rotational speed of 8c is also below the rated rotational speed of 70 (Hz), for example. For this reason, only the capability below a rated output can be output. In this bypass control method, the ice slurry liquid 8d flowing out from the steam compression refrigerator 8 is returned as cold water via the bypass pipe 18 to obtain a cold water inlet temperature of 5 (° C.) or less capable of making ice in a short time, The time to reach the rated output can be shortened.

Next, a first embodiment of the operation control apparatus for the steam compression refrigerator according to the present invention will be described with reference to FIG.

FIG. 3 is a structural layout diagram showing Example 1 of the operation control device of the steam compression refrigerator.
Reference numerals 18A to 18D denote bypass pipes, which are connected or piped between the path of the forward pipe 12 and the path of the return pipe 16. Reference numerals 19A to 19D denote bypass control valves, which are arranged corresponding to the paths of the bypass pipes 18A to 18D, respectively. The bypass control valves 19A to 19D are controlled to be opened and closed by the measured value of the cold water thermometer 19a that detects the temperature of the cold water flowing through the return pipe 16. The sensor part of the cold water thermometer 19a is inserted into the return pipe 16, and the cold water sent from the ice heat storage tank 13 and the ice slurry liquid 8d sent from the bypass pipes 18A to 18D are mixed. The temperature of the cold water in the return pipe 16 is measured.

An ice heat storage tank cold water thermometer 13a is disposed on the return pipe 16 on the outlet side of the ice heat storage tank 13 and detects the temperature of the cold water flowing out of the ice heat storage tank 13.

The characteristic point of the first embodiment according to the present invention is that it has a configuration in which a plurality of bypass control valves 19A to 19D and corresponding bypass pipes 18A to 18D are provided in addition to the configuration of the embodiment shown in FIG. is there. Since it was configured in this way, the bypass amount of each bypass control valve can be reduced even for ON-OFF control compared to the single bypass pipe 18, and the opening / closing operation is performed stepwise based on the cold water thermometer 19a. The variation width of the cold water temperature after bypass due to the opening / closing operation of the valve can be suppressed. Therefore, it is possible to perform operation control in which the steam compression refrigerator 8 is further stabilized.
However, since the bypass pipes 18A to 18D and the bypass control valves 19A to 19D are increased, this system becomes complicated and there is a bottleneck that increases the construction cost.

The other components of the first embodiment of the operation control device for the steam compression refrigerator according to the present invention are substantially the same as those shown in FIG.
Also, the operation of the operation control device for the steam compression refrigerator according to the present invention is substantially the same as that shown in FIG.

Next, a second embodiment of the operation control apparatus for the steam compression refrigerator according to the present invention will be described with reference to FIG.

FIG. 4 is a configuration layout diagram showing a second embodiment of the operation control device of the steam compression refrigerator.

A heat exchanger means 20 is interposed between the path of the forward pipe 12 and the path of the return pipe 16. The heat exchanger means 20 is composed of a primary side pipe 20a and a secondary side pipe 20b, and the primary side pipe 20a is branched from the forward pipe 12 and connected to the forward pipe 12. The secondary side pipe 20 b is branched from the return pipe 16 and connected to the return pipe 16. The loop of the primary side pipe 20a includes a plurality of control valves 20c and 20d, and the loop of the secondary side pipe 20b includes a plurality of control valves 20e and 20f. The opening degree of these control valves 20c to 20f is adjusted so that the measured value by the chilled water thermometer 19a becomes a set value, and the ice slurry liquid 8d flowing through the primary side pipe 20a and the secondary side pipe 20b are passed through. Control the flow rate of cold water.

Other components of the second embodiment of the operation control apparatus for the steam compression refrigerator according to the present invention are substantially the same as those shown in FIG.
Further, the operation of the second embodiment of the operation control device for the steam compression refrigerator according to the present invention is substantially the same as that shown in FIG.

Next, a third embodiment of the operation control apparatus for the steam compression refrigerator according to the present invention will be described with reference to FIG.

FIG. 5 is a configuration diagram showing a third embodiment of the operation control device of the steam compression refrigerator.
A bypass control valve 19 is interposed in a bypass pipe 18 connected between the path of the forward pipe 12 and the path of the return pipe 16. A cold water pump 21 is arranged in parallel adjacent to the bypass control valve 19 and is arranged in parallel with a bypass pipe connected between the path of the forward pipe 12 and the path of the return pipe 16. Connected between the paths 22. 23 is a control valve composed of a two-way valve, just before joining the bypass pipe 18 to which the bypass control valve 19 is connected. The bypass valve 23 is interposed in the path of the return pipe 16 and is controlled by the cold water thermometer 19a. Similar to the valve 19, the opening of the valve is controlled.

Since the third embodiment has the above-described configuration, all of the ice slurry liquid fed from the slurry pump 14 is fed from the return pipe 16 to the evaporator 8 a via the bypass control valve 19 connected to the bypass pipe 18. At the same time, the ice slurry liquid or the cold water 8d in the evaporator 8a is always kept at a low temperature without being sent to the ice heat storage tank 13. Accordingly, the start-up of the steam compression refrigerator 8 can be promptly operated. Specifically, when the bypass control valve 19 is fully open, that is, when the temperature of the chilled water thermometer 19a shows a high value, the control valve 23 is throttled to perform full bypass. At this time, by this operation, the cold water pump 21 is operated as necessary in order to supplement the collapse of the flow rate balance of the cold water flowing into and out of the ice heat storage tank 13.

Other components of the third embodiment of the operation control apparatus for the steam compression refrigerator according to the present invention are substantially the same as those shown in FIG.

1 is a configuration layout diagram showing one example in an embodiment of an operation control device for a steam compression refrigerator according to the present invention. FIG. It is a driving | operation control characteristic figure which shows the temperature (degreeC) of cold water with respect to the operating time (min) of the water vapor compression refrigerator which concerns on this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram which shows Example 1 of the operation control apparatus of the steam compression refrigerator which concerns on this invention. It is a block diagram which shows Example 2 of the operation control apparatus of the steam compression refrigerator which concerns on this invention. It is a block diagram which shows Example 3 of the operation control apparatus of the steam compression refrigerator which concerns on this invention. It is a block diagram which shows an example of the ice thermal storage system in a prior art.

8 Steam Compressor Refrigerator 8a Steam Compressor Refrigerator Evaporator 8b Steam Compressor Refrigerator Condenser 8c Steam Compressor Refrigerator Compressor 8d Ice Slurry Liquid or Cold Water 9 Water Drop Scattering Demister 10 Stirrer 11 Compressor Blade 12 Tube 13 Ice heat storage tank 13a Ice heat storage tank cold water thermometer 14 Slurry pump 14a Flow meter 14b Inverter 15 Ice slurry thermometer 16 Return pipe 17 Control valve 18 Bypass pipe 18A Bypass pipe 18B Bypass pipe 18C Bypass pipe 18D Bypass pipe 19 Bypass control valve 19a Cold water thermometer 19A Bypass control valve 19B Bypass control valve 19C Bypass control valve 19D Bypass control valve 20 Heat exchanger means 20a Heat exchanger means primary pipe 20b Heat exchanger means secondary pipe 20c Control valve 20d Control valve 20e Control valve 20f Control valve 21 Chilled water pump 2 bypass passage 23 valve

Claims (1)

Evaporator deployed prevention demister and a stirrer water droplet scattering, and vapor compression refrigeration machine comprising the condenser and the compressor, the forward pipe for Nagareoku ice slurry generated in the preceding Symbol evaporator in an ice thermal storage tank, before a return pipe for Nagareoku cold water from Kikori storage tank before Symbol evaporator, said to have started the slurry pump disposed forward pipe, in the evaporator by the disposed return pipe and water level meter A control valve that detects the water level of the ice slurry liquid and controls the valve opening; an ice slurry thermometer and a flow meter that are disposed in the forward pipe and measures the temperature and flow rate of the ice slurry liquid; the forward pipe and the A bypass control valve that is interposed in a bypass pipe connected between the return pipe and controls the valve opening degree by a measured value of a cold water thermometer provided in the return pipe, and is provided in the return pipe; A control valve for controlling the valve opening by the measured value of the cold water thermometer; Operation control device for a steam compression refrigeration machine, characterized in that and a chilled water pump for controlling the cold water to flow in or out to the scan line connected to the bypass passage disposed in parallel and the ice heat storage tank.

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