JP2007127321A - Cold water load factor controller for refrigerator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cold water load factor controller for a refrigerator realizing high energy saving by predicting refrigerator electric power by the controller, and controlling a cold water load factor (a cold water flow rate) of a cold water pump so as to minimize the refrigerator electric power. <P>SOLUTION: In a cold water manufacturing system using a plurality of refrigerators 23, a cooling water temperature measuring means 27 is provided for measuring a cooling water temperature of a refrigerator inlet, and a cold water load factor per cooling water temperature and a partial load characteristic being a function of the refrigerator electric power are inputted into the controller 26. In the controller, a cold water temperature and the cold water flow rate of a return passage side are measured by a return passage side cold water thermometer 15 and a return passage side flowmeter 13, a cold water total heating value is calculated on the basis of these, a refrigerator inlet cooling water temperature is measured by the cooling water temperature measuring means, each refrigerator electric power per load factor is calculated from the partial load characteristic, a combination of load factors satisfying a necessary refrigerating capacity with respect to the cold water total heating value and minimizing a total of electric power is predicted, and a rotational frequency of the cold water pump is controlled such that the predicted load factor is provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a cold water load factor control device for a refrigerator that shares a cold water load so that the efficiency of the refrigerator is optimized in a cold water production system using a plurality of refrigerators.

  Chilled water production systems are used in a wide range of fields such as air conditioning and equipment cooling in factories, hospitals, and buildings. However, since a large amount of energy is consumed, it is indispensable to construct a system that considers energy saving.

FIG. 2 shows a conventional general cold water production system. In the figure, reference numeral 11 denotes a cold water load composed of an air conditioner, a heat exchanger and the like, which is a use point of cold water. Reference numeral 12 denotes a forward side cold water secondary header provided on the inlet side of the cold water load 11, reference numeral 13 denotes a return side cold water flow meter provided on the outlet side of the cold water load 11, and reference numeral 14 denotes an outgoing side cold water secondary header 12. A forward side header thermometer, 15 is a return side cold water thermometer, 16 is a plurality of (three in the figure) secondary chilled water pumps, which are secondary chilled water pumps 1 to 3. Reference numeral 17 is a forward cold water primary header, 18 is a return cold water primary header, 19 is a refrigerator outlet flowmeter, and 20 is a plurality of (two in the figure) primary cold water pumps. This is a secondary cold water pump 2. Reference numeral 21 denotes a refrigerator outlet thermometer, reference numeral 22 denotes a refrigerator inlet thermometer, reference numeral 23 denotes a plurality of (two in the figure) turbo refrigerators, which are the turbo refrigerator 1 and the turbo refrigerator 2. Reference numeral 24 denotes a plurality of (two in the figure) cooling water pumps, which are the cooling water pump 1 and the cooling water pump 2. Reference numeral 25 denotes a plurality of cooling towers (two in the figure), which are the cooling tower 1 and the cooling tower 2. Reference numeral 26 denotes a control device.
In this system, two turbo chillers 23 are arranged, each having a primary chilled water pump 20, a cooling water pump 24, and a cooling tower 25. Moreover, the secondary chilled water pump 16 is employ | adopted for the water supply to the chilled water loads 11, such as an air-conditioner coil and a heat exchanger which are use points. The chilled water produced by each turbo chiller 23 is sent to the forward-side chilled water primary header 17 by each primary chilled water pump 20 and merges, and then passes through the forward-side chilled water secondary header 12 by the secondary chilled water pump 16. Water is sent to the cold water load 11 which is a use point. The sent cold water returns to the return path side cold water primary header 18 and returns to each turbo refrigerator 23 after heat exchange.

  The system in FIG. 2 controls the number of operating turbo chillers 23 according to the load (heat amount) of air conditioner coils and heat exchangers that are use points. The chilled water temperature meter 15 and the chilled water flow meter 13 attached to the inlet side of the chilled water primary header 18 measure the chilled water temperature on the return path side and the secondary chilled water flow rate. Based on these measured values, the control device 26 calculates the total amount of chilled water heat and determines the number of operating turbo chillers 23.

  Further, the system of FIG. 2 performs the rotational speed control of the primary chilled water pump 20 in accordance with the ratio between the primary chilled water flow rate and the secondary chilled water flow rate. Further, the control device 26 measures the primary chilled water flow rate by the refrigerator outlet flow meter 19 attached to the outlet of each turbo refrigerator 23 and totals them. The result is compared with the above secondary chilled water flow rate, the flow rate of the primary chilled water pump 20 is determined so that the secondary chilled water flow rate = the primary chilled water flow rate, and the rated flow rate ratio (= the rated capacity ratio of the refrigerator). The number of rotations is controlled by.

  In addition, as a conventional technology, in an air conditioning facility that circulates and supplies a cold / hot medium, air conditioning equipment is equipped with a simulation model of equipment such as a cool / heat generator and a pump constituting the air conditioning facility, and the evaluation function is minimized or maximized by simulation. An optimal control target value to be determined is determined and the air conditioning equipment is operated with the optimal control target value (for example, see Patent Document 1).

JP 2005-134110 A

  Since the conventional chilled water production system performs the control as described above, the chilled water load (heat quantity) is evenly distributed according to the rated flow rate ratio of the chilled water pump regardless of the efficiency of the refrigerator. The capacity of the high refrigerator is not fully demonstrated, and wasteful power is consumed. If the chilled water load factor (chilled water flow rate) is controlled so that the electric power of the refrigerator is minimized, a higher energy saving effect is produced.

  The air conditioning facility described in Patent Document 1 includes a simulation model of a device such as a cold / hot heat generator or a pump that constitutes the air conditioning facility, and determines the optimum control target value that minimizes or maximizes the evaluation function by simulation. The air conditioning equipment is operated with the control target value, and the cold water load is not shared so that the efficiency of the refrigerator is optimized.

  The present invention has been made to solve the above-described problems, and predicts the power of the refrigerator as needed by the control device, and the cold water load factor (cold water) of the cold water pump so that the power of the refrigerator is minimized. The present invention provides a chilled water load factor control device for a refrigerator that realizes higher energy saving by controlling the flow rate.

  In the chilled water load factor control device for a refrigerator according to the present invention, a chilled water load that is a use point of chilled water, a forward-side chilled water header provided on the inlet side of the chilled water load, and a return provided on the outlet side of the chilled water load. Roadside chilled water flow meter, Outward side header thermometer, Return side chilled water thermometer, Return side chilled water header, chiller outlet flow meter, multiple primary chilled water pumps, chiller outlet thermometer, refrigeration An inlet thermometer, a plurality of turbo chillers, a plurality of cooling water pumps, a plurality of cooling towers, and a control device are provided, and the chilled water produced by each turbo chiller is converted into each primary chilled water. In a chilled water production system using multiple chillers configured to pump water to the chilled water load through the forward-side chilled water header, exchange heat with the chilled water load, and return to each turbo chiller through the return-side chilled water header Of the refrigerator entrance A cooling water temperature measuring means for measuring the rejection water temperature is provided, and a partial load characteristic that is a function of the refrigerator cooling water load factor and the refrigerator power for each cooling water temperature is input to the control device. Measure the chilled water temperature and chilled water flow rate on the return side with the flowmeter and the return side flow meter, calculate the total amount of chilled water based on these measured values, and measure the cooling water temperature at the refrigerator inlet with the cooling water temperature measurement means. Calculate the power of each refrigerator for each load factor from the partial load characteristics, and predict the combination of load factors that satisfies the required refrigeration capacity for the total amount of chilled water and minimizes the total power from the result. The number of rotations of the chilled water pump is controlled so that the predicted load factor is obtained.

  According to this invention, the power of the refrigerator is minimized and a high energy saving effect can be obtained.

Embodiment 1 FIG.
FIG. 1 is a system configuration diagram showing a chilled water load factor control device for a refrigerator according to Embodiment 1 of the present invention.
In the figure, reference numeral 11 denotes a cold water load composed of an air conditioner, a heat exchanger and the like, which is a use point of cold water. Reference numeral 12 denotes a forward side cold water secondary header provided on the inlet side of the cold water load 11, reference numeral 13 denotes a return side cold water flow meter provided on the outlet side of the cold water load 11, and reference numeral 14 denotes an outgoing side cold water secondary header 12. A forward side header thermometer, 15 is a return side cold water thermometer, 16 is a plurality of (three in the figure) secondary chilled water pumps, which are secondary chilled water pumps 1 to 3. Reference numeral 17 is a forward cold water primary header, 18 is a return cold water primary header, 19 is a refrigerator outlet flowmeter, and 20 is a plurality of (two in the figure) primary cold water pumps. This is a secondary cold water pump 2. Reference numeral 21 denotes a refrigerator outlet thermometer, reference numeral 22 denotes a refrigerator inlet thermometer, reference numeral 23 denotes a plurality of (two in the figure) turbo refrigerators, which are the turbo refrigerator 1 and the turbo refrigerator 2. Reference numeral 24 denotes a plurality of (two in the figure) cooling water pumps, which are the cooling water pump 1 and the cooling water pump 2. Reference numeral 25 denotes a plurality of cooling towers (two in the figure), which are the cooling tower 1 and the cooling tower 2. Reference numeral 26 denotes a control device.
In this system, two turbo chillers 23 are arranged, each having a primary chilled water pump 20, a cooling water pump 24, and a cooling tower 25. Moreover, the secondary chilled water pump 16 is employ | adopted for the water supply to the chilled water loads 11, such as an air-conditioner coil and a heat exchanger which are use points. The chilled water produced by each turbo chiller 23 is sent to the forward-side chilled water primary header 17 by each primary chilled water pump 20 and merges, and then passes through the forward-side chilled water secondary header 12 by the secondary chilled water pump 16. Water is sent to the cold water load 11 which is a use point. The sent cold water returns to the return path side cold water primary header 18 and returns to each turbo refrigerator 23 after heat exchange.
The above configuration is the same as the conventional configuration.

The feature of the present invention is that a refrigerator inlet cooling water thermometer 27 is provided as means for measuring the cooling water temperature at the refrigerator inlet. The control device 26 is provided with means for inputting in advance the partial load characteristics of the refrigerator 23. The partial load characteristic is a function representing a refrigerator cold water load factor and refrigerator power for each cooling water temperature. Further, the control device 26 measures the chilled water temperature and the secondary chilled water flow rate on the return path side with the thermometer 15 and the flow meter 13 attached to the inlet of the return path side chilled water primary header 18, and the total chilled water flow is based on these measured values. A means for calculating the amount of heat is provided. Thereby, the control apparatus 26 determines required refrigerating capacity. Furthermore, the control device 26 measures the refrigerator inlet cooling water temperature by the refrigerator inlet cooling water thermometer 27, calculates each refrigerator electric power for each cold water load factor from the partial load characteristics, and the result. Means are provided for predicting a combination of load factors that satisfies the required refrigeration capacity with respect to the total amount of chilled water heat and that minimizes the total power. And the rotation speed of a cold water pump is controlled so that it may become the estimated load factor. Further, the control means 26 takes into account the case where the partial load characteristics fluctuate due to a decrease in the efficiency of the refrigerator due to deterioration over time, etc., and after performing the above control, measures the actual refrigerator power, Means are provided for updating the load characteristics.
The rated refrigeration capacity of the turbo chiller 23 is 2637 KW for both units.

Next, specific embodiments of the present invention will be described with reference to FIG. 1 and Tables 1 to 4.
Based on the partial load characteristics of the refrigerator, a function of the refrigerator cold water load factor and the refrigerator power in units of 1 ° C. of the cooling water temperature is created and input to the control device 26. Tables 1 and 2 are functions of the load factor and the refrigerator power for each cooling water temperature. However, due to the characteristics of the refrigerator, operation with a load factor of 20% or less is not possible. Moreover, since the cooling water of the turbo refrigerator 23 is controlled to be 13 ° C. to 32 ° C. by the inverter machine and 20 ° C. to 32 ° C. by the constant speed machine, data outside this range is not used.

Next, the forward path header thermometer 14 attached to the forward path side cold water secondary header 12, the return path side cold water thermometer 15 provided on the inlet side of the return path side cold water primary header 18, and the return path side cold water flow meter 13. The cold water temperature on the side, the cold water temperature on the return path side, and the secondary cold water flow rate are measured. The control device 26 calculates the total amount of cold water based on these measured values. In the case of FIG. 1, since the forward header temperature = 7 ° C., the return header temperature = 17 ° C., and the secondary chilled water flow rate = 318.3 m ³ / h, the chilled water total heat quantity (KW) = (17−7) × It becomes 318.3 * 1.16 = 3692KW.

Furthermore, the inlet cooling water temperature of the operating centrifugal chiller is measured, and the electric power of each chiller is calculated every 1% at a load factor of 20% to 100% from the partial load characteristic function. Based on the result, a combination of load factors that satisfies the refrigerating capacity necessary for the total amount of cold water and that minimizes the total power is predicted.
In order to satisfy the total amount of heat of cold water = 3692 KW, the total load factor of the turbo refrigerator 1 and the turbo refrigerator 2 needs to be 140%. Since the cooling water measurement temperature is 22 ° C., the power of each refrigerator is calculated every 1% with a load factor of 20% to 100% from the partial load characteristics at the cooling water temperature of 22 ° C. Here, for convenience of explanation, Table 3 shows the results in increments of 10%. From the combination result, when the refrigerator 1 is operated at 60% and the refrigerator 2 is operated at 80%, it becomes 497 kW, and the power becomes the minimum.

Based on the load factor calculated above, the required amount of chilled water for each primary chilled water pump 10 (= the load factor of the refrigerator predicted above × the rated chilled water amount) is determined, and the performance characteristics of the primary chilled water pump (Table 4) The frequency of each primary chilled water pump is predicted from the function of the flow rate and frequency of each primary chilled water pump shown. However, due to the characteristics of the refrigerator, operation at a flow rate of 50% or less or 110% or more is not possible, so data in this range is not used.
Since the combination of operating the refrigerator 1 at 60% and the refrigerator 2 at 80% was selected, the operating frequency of the primary chilled water pump 1 is 31.3 Hz from Table 4, and the operating frequency of the primary chilled water pump 2 Becomes 38.3 Hz. The number of revolutions of the primary chilled water pump is controlled by this frequency.

上記制御を実施後、冷凍機の電力、冷却水温度の計測を実施し、制御装置２６にデータを蓄積する。そして、蓄積したデータにより、自動的に部分負荷特性を補正する。

After the above control is performed, the power of the refrigerator and the cooling water temperature are measured, and data is accumulated in the control device 26. Then, the partial load characteristics are automatically corrected based on the accumulated data.

Embodiment 2. FIG.
In the first embodiment, the partial load characteristic uses a function of the chilled water load factor and the chiller power for each cooling water temperature, but a function of the chilled water load factor and the chiller performance coefficient (COP) for each cooling water temperature. Can also be used. COP is expressed by the quantity of chilled water heat (= load factor × rated refrigeration capacity) / refrigerator power, and gives exactly the same result as a function by power.

It is a system block diagram which shows the cold water load factor control apparatus of the refrigerator in Embodiment 1 of this invention. It is a system block diagram which shows the conventional common cold water manufacturing system.

Explanation of symbols

11 Cold water load (use point for cold water)
12 Outbound side cold water secondary header 13 Return path side cold water flow meter 14 Outbound side header thermometer 15 Return path side cold water thermometer 16 Secondary chilled water pump 17 Outbound side cold water primary header 18 Return path side cold water primary header 19 Refrigerator outlet flow meter 20 Primary chilled water pump 21 Refrigerator outlet thermometer 22 Refrigerator inlet thermometer 23 Turbo chiller 24 Cooling water pump 25 Cooling tower 26 Control device 27 Means for measuring the cooling water temperature at the chiller inlet (refrigerator inlet cooling water temperature Total)

Claims (3)

Chilled water load, which is the chilled water use point, the outward chilled water header provided on the inlet side of the chilled water load, the return side chilled water flow meter provided on the outlet side of the chilled water load, the outgoing header thermometer, and the return side Chilled water thermometer, return side chilled water header, refrigerator outlet flow meter, multiple primary chilled water pumps, refrigerator outlet thermometer, refrigerator inlet thermometer, multiple turbo refrigerators, multiple A cooling water pump, a plurality of cooling towers, and a control device, and the chilled water produced by each centrifugal chiller is sent to the chilled water load through the outgoing chilled water header by each primary chilled water pump, In a chilled water production system using a plurality of refrigerators configured to return to each turbo refrigerator through a return path side chilled water header after heat exchange with a chilled water load,
A cooling water temperature measuring means for measuring a cooling water temperature at the inlet of the refrigerator is provided, and a partial load characteristic that is a function of a refrigerator cooling water load factor and a refrigerator power for each cooling water temperature is input to the control device, and the control device Measures the chilled water temperature and the chilled water flow rate on the return side with the return side chilled water thermometer and the return side flow meter, calculates the total amount of chilled water based on these measured values, and further uses the cooling water temperature measuring means to Measure the cooling water temperature at the inlet of the machine, calculate the chiller power for each chilled water load factor from the partial load characteristics, and satisfy the required refrigeration capacity for the total amount of chilled water from the result, and the total power A chilled water load factor control device for a refrigerator, wherein a combination of load factors that is minimized is predicted, and the number of revolutions of the chilled water pump is controlled to achieve the predicted load factor.   The control device updates the partial load characteristic of the control device by measuring the actual refrigerator power when the partial load characteristic varies due to a decrease in efficiency of the refrigerator due to deterioration over time. Cold water load factor control device for refrigerators.   As a partial load characteristic, a function of the refrigerator cold water load factor and the refrigerator coefficient of performance (COP) for each cooling water temperature is used instead of the function of the refrigerator cold water load factor and the refrigerator power for each cooling water temperature. The cold water load factor control device for a refrigerator according to claim 1 or 2.

Images