JP2505121Y2 - Heat medium controller for heating and cooling heat source plant - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention provides a wide range of cooling and heating by continuously supplying a heat medium such as cold water or hot water to a radiator on the side of many consumers over the whole day of the year. The present invention relates to a heat medium control device for a cooling / heating heat source plant, which is applied to a district cooling / heating heat source plant or the like.

[Prior Art] In this type of heating and cooling heat source plant, the demand amount of the heat medium on the customer side, that is, the heat amount demand amount, continuously and largely changes. As a flow rate through a heat medium generator such as a refrigerator or a hot water generator, it is necessary to secure a constant flow rate with respect to the rating of the generator, and normally, the rated flow rate is maintained,
As a means for coping with the change in the demand amount on the consumer side, a bypass passage is provided in the piping of the supply side plant including the heat medium generator.

As an example of setting the bypass path, the one having the following configuration is conventionally known. In the following description, the heat medium generator is a refrigerator for simplification of the description, and the case of a cooling plant in which the heat medium is cold water is described, but in the case of a heating plant, the heat medium generator is hot water. Generator,
There is no difference in structure only by replacing the heating medium with hot water.

FIG. 9 shows a piping system diagram of a one-stage pump type cooling heat source plant. In FIG. 9, A is a supply side plant, which comprises a refrigerator 1, a pump 2 for sending cold water, and a pipe 3. B is a customer-side plant, which is composed of a plurality of customers 4 such as an air conditioner that consumes the amount of heat of cold water and a pipe 5 that connects these customers 4 in parallel. A cooling heat source plant is configured by connecting the pipe 3 of the supply side plant A and the pipe 5 of the customer side plant B so as to form a circulation path of cold water.

In the above cooling heat source plant, a bypass path 6 is provided in the pipe 3 of the supply side plant A, and the bypass path 6 is provided.
Further, a valve 7 for detecting the delivery pressure of the pipe 3 and controlling the opening according to the detected pressure to control the bypass flow rate is installed.

FIG. 10 shows a piping system diagram of a cooling heat source plant of a two-stage pump system. In this case, a pump 8 is provided in the piping 3 of the supply side plant A separately from the pump 2, and the supply to the customer side plant B is performed. The flow rate is controlled to be a constant flow rate. In FIG. 10, parts that are the same as or correspond to those in FIG. 9 are given the same reference numerals, and descriptions thereof are omitted.

By the way, in the conventional chilled water control device for the cooling heat source plant shown in FIG. 9 and FIG. 10, no bypass valve is provided in the middle of the pipe 5 of the consumer side plant B. Some of the pipes are provided with a bypass valve at the end, but this is caused by water flow stagnation in the pipe 5 of the customer-side plant B when the heat load on the customer side is extremely small or when cold water is not used. The purpose is to prevent the supply temperature from fluctuating and the thermal expansion and contraction of the pipe 5 itself, and the purpose is different from the present invention. Therefore, the capacity is set to a necessary amount for preventing temperature fluctuations and thermal expansion and contraction, and is much smaller than the amount of cold water delivered from the refrigerator 1. Moreover, it is necessary to provide it at the end portion, and it is useless if it is provided in the middle of the pipe.

[Problems to be Solved by the Invention] In the conventional cooling water control device for a cooling heat source plant as described above, when the demanded heat amount of the customer side plant B is small and the amount of water passing through the pipe 5 is controlled to be small. Most of the cold water sent from the refrigerator 1 flows through the bypass passage 6 of the supply side plant A and returns to the refrigerator 1.

Under such conditions, the refrigerator 1 is started and stopped (hereinafter referred to as start / stop) based on the detection of the outlet or inlet temperature of the refrigerator 1 to control the chilled water temperature. No phenomenon occurs.

That is, since the temperature rise amount of the cold water flowing and circulating in the bypass path 6 of the supply side plant A is very small, when the refrigerator 1 is started, the cold water temperature of the supply side plant A rapidly decreases. Since the bypass flow rate in the supply side plant A is large, the outlet or inlet temperature of the refrigerator 1 is almost determined by the temperature of the chilled water circulating in the supply side plant A, so that the stop condition of the refrigerator 1 is rapidly increased. To establish.

On the other hand, at this time, the cold water in the pipe 5 of the customer side plant B has risen in temperature, and even after the refrigerator 1 is stopped, the cold water that has risen from the pipe 5 of the consumer side plant B to the pipe 3 of the supply side plant A Continues to flow in, and this small amount of high-temperature cold water mixes with the circulating cold water of the supply-side plant A, so that the supply-side plant A
The cold water temperature rises, and the starting condition of the refrigerator 1 is rapidly established.

In this way, when the demanded heat quantity on the customer side becomes small, only the cold water temperature in the supply side plant A fluctuates up and down without changing the cold water temperature of the customer side plant B, and the refrigerator is Start and stop 1 unnecessarily. Therefore, the chilled water temperature of the consumer side plant B greatly changes beyond the preset temperature range for starting and stopping the refrigerator 1.

It is also conceivable to separately provide a small-capacity refrigerator as a means for coping with a small amount of heat demanded by the consumer side without starting and stopping the refrigerator 1, but in this case, a small-capacity refrigerator and It is necessary to add an attached piping system, etc., leading to an increase in equipment cost and space.

The present invention has been made in view of the above circumstances, and has a simple heating and cooling system that can reduce the frequency of start and stop and improve the temperature control performance when the amount of heat required by the customer is small. An object is to provide a heat medium control device for a plant.

[Means for Solving the Problems] In order to achieve the above object, the heat medium control device for a heating and cooling heat source plant according to claim 1 is a heat medium generator that generates a heat medium for cooling and heating, and the generated heat. A piping of the supply side plant equipped with a pump for sending the medium and a piping outside the cooling / heating heat source machine formed by connecting in parallel the consumers consuming the heat quantity possessed by the heating medium form a circulation path for the heating medium. In the heat medium control device of the heating and cooling heat source plant, the bypass path is provided at an appropriate position of the pipe outside the cooling and heating heat source machine, and the bypass path is controlled to open and close according to the heat load on the consumer side. It is provided with a valve.

The heat medium control device for a heating / cooling heat source plant according to claim 2, wherein, as the opening / closing condition of the bypass valve, the heat load on the customer side is open when the output is lower than or equal to the output lower limit of the heat medium generator having the minimum capacity, and is higher than or equal to the output lower limit. It is set to be closed when.

Further, the heat medium control device of the cooling and heating heat source plant according to claim 3 continuously controls the opening degree of the bypass valve to reach the delivery pressure from the supply side plant or the end of the pipe of the consumer side plant. It is configured to control the pressure.

[Operation] According to the invention of claim 1, when the required heat amount of the customer side plant, that is, the heat load becomes small, the bypass valve at the appropriate position of the pipe outside the cooling / heating heat source machine room is opened, It is possible to secure the amount of heat medium delivered from the supply side plant to a predetermined amount or more, and it is possible to reduce the bypass amount in the supply plant. Thereby, the temperature of the heat medium in the supply side plant is kept close to the temperature of the consumer side plant, and the frequency of starting and stopping the heat medium generator decreases,
Also, the temperature change of the heat medium becomes gentle.

Particularly, according to the second aspect of the invention, it is opened when the heat load of the consumer side plant is below the output lower limit value of the heat medium generator of the minimum capacity of the supply side plant, and closed when above the output lower limit value. As a result, it is possible to properly provide an increase in the heat load while preventing an unnecessary start / stop of the heat medium generator and a rapid rise / fall of the heat medium temperature accompanying it.

Further, according to the invention of claim 3, the opening degree of the bypass valve is continuously controlled to control the delivery pressure of the supply side plant or the ultimate pressure of the end portion of the pipe of the customer side plant. It is not necessary to provide a bypass path for controlling the delivery pressure in the supply side plant, and therefore, the entire delivery flow rate from the heat medium generator flows to the customer side plant, so the heat load on the customer side It is possible to prevent an unnecessary start / stop of the heat medium generator and a large change in the temperature of the heat medium due to the decrease of the heat medium generator.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a piping system diagram of a one-stage pump type heating and cooling heat source plant. In FIG. 1, the same parts as those of the conventional example shown in FIG. 9 are designated by the same reference numerals, and detailed description thereof will be omitted. To do.

In FIG. 1, reference numeral 10 denotes a bypass passage provided at an appropriate position of the pipe 5 of the consumer side plant B.
10 is a bypass valve that is controlled to open and close according to the heat load on the customer side, that is, according to the flow rate detected by the cold water flow meter 12.
11 are intervening. The opening degree of this bypass valve 11 is the refrigerator 1.
The flow rate is set to about 25% of the delivery flow rate of.

The opening / closing condition of the bypass valve 11 is set to open when the heat load on the consumer side is equal to or lower than the output lower limit value of the refrigerator 1 having the minimum capacity, and is set to close when it is equal to or higher than the output lower limit value.

In addition, in the opening / closing condition of the bypass valve 11, in order to prevent the frequent opening / closing even when the output lower limit value or more is exceeded, a hysteresis is given to the time margin or the value of the heat load.

In the chilled water control device of the cooling heat source plant configured as described above, the refrigerator 1 having the minimum heat load on the consumer side plant B is used.
When the output is below the output lower limit value, the bypass valve 11 is opened by the signal from the flow meter 12, and the amount of chilled water sent from the pipe 3 of the supply side plant A to the pipe 5 of the customer side plant B becomes a predetermined amount or more. Secured and bypass path 6 of supply side plant A
Bypass amount is reduced or becomes zero. Further, since the temperature difference between the cold water flowing in and out of the radiator 4 in the consumer unit of the customer side plant B is diluted with the bypass cold water flowing in the bypass passage 10 on the customer side, The temperature difference of cold water becomes small.

As a result, the cold water temperature in the supply-side plant A is maintained at a temperature close to the cold water temperature in the customer-side plant B, and the amount of water held in the pipe 5 of the customer-side plant B is large. The frequency decreases, and the temperature of the cold water can be gradually increased and decreased with the start and stop of the refrigerator 1.

Further, when the heat load of the consumer side plant B becomes equal to or higher than the output lower limit value of the refrigerator 1 having the minimum capacity, the starting / stopping operation of the refrigerator 1 becomes unnecessary, so the bypass valve 11 is closed and the consumer It is possible to prepare for an increase in heat load on the side plant B.

FIG. 2 shows another embodiment of the present invention, showing a piping system diagram of a two-stage pump type cooling heat source plant.
The difference from the above embodiment is that the piping 3 of the supply side plant A is
In addition to the pump 2, a variable capacity pump 8 for controlling the supply flow rate to the consumer side plant B to a constant flow rate is provided separately,
Since other configurations are the same as those in FIG. 10, the corresponding portions are denoted by the same reference numerals and the description thereof will be omitted.

Since the opening / closing condition of the bypass valve 11 in this embodiment has a flow rate range in which there is no power loss of the pump 8 even when the bypass valve 11 is open, the inside of the pipe 5 of the customer side plant B is It may be set to close when the flow rate exceeds the above range and the heat load on the customer side exceeds the output lower limit value of the refrigerator 1 having the minimum capacity.

FIG. 3 shows a piping system diagram of a cooling heat source plant according to another embodiment of the present invention. In this embodiment, a water supply amount to a customer side plant B is provided without providing a bypass passage in a supply side plant A. Is determined by controlling the number of operating refrigerating machines 1, the bypass valve 11 of the consumer side plant B is continuously controlled based on the detection signal of the pressure detector 13, and the delivery pressure of the supplying side plant A is controlled. Alternatively, the ultimate pressure at the end of the consumer side plant B is controlled. In FIG. 3, parts that are the same as or correspond to those in FIG. 1 are given the same reference numerals, and descriptions thereof will be omitted.

In the chilled water control device of the cooling heat source plant configured as shown in FIG. 3, since there is no bypass passage for controlling the delivery pressure of the supply side plant A, regardless of the fluctuation of the heat load on the customer side, the chilled water Since the flow rate is made to flow to the consumer side plant B, it is possible to reduce the frequency of starting and stopping the refrigerator 1 and always exert the effect of making the temperature change of the cold water gentle.

In each of the above-described embodiments, the cooling heat source plant using the refrigerator 1 as the heat medium generator has been described. However, even when applied to the heating heat source plant using the hot water generator, the same effects as those of the above embodiments are obtained. Play.

Further, the present inventor conducted simulations for the control device of the present invention and the control device of the conventional example shown in FIG. 9 based on the conditions of a heat supply cooling and heating plant at a certain place, and compared and examined the results. I will describe it below.

Fig. 4 shows the system flow when the demand for chilled water is low in the heat supply cooling and heating plant that performs simulation. 1) In the system of this invention, the bypass flow rate on the customer side is set to about 25% of the water flow rate 211 (T / H) of the refrigerator 1 (Case 2). That is, the flow rates FE, FU, FL, FB (T / H) of the respective parts in FIG. 4 are as shown in the table of FIG. 8 in case 1 and case 2.

FIG. 5 is a model configuration diagram for simulating the system of FIG. 4, and the parameters of the model in case 1 and case 2 are as shown in the table of FIG.

As a result of the simulation above, when the bypass flow on the customer side is zero, that is, the temperature of each part in case 1 is as shown in FIG. 6, and when there is the bypass flow on the customer side, that is, the case In the case of 2, the temperature of each part is as shown in FIG.

From the results of the simulation above, in case 1, the frequency of starting and stopping the refrigerator 1 is high, and the temperature of the chilled water supplied to the customer side plant B is 5 ° C to 11 ° C.
And has a large width.

In case 2, the start / stop frequency of the refrigerator 1 is case 1
Compared with the above case, the temperature of the chilled water supplied to the customer side plant B will fall within the range of 5 ° C to 9 ° C.

 From this, it can be seen that this device is effective.

[Advantages of the Invention] As described above, according to the inventions of claims 1 and 2, even when the heat load on the customer side becomes small, a heat medium delivery of a predetermined amount or more is ensured from the supply side plant. Therefore, it is possible to lower the bypass amount in the supply side plant to reduce the frequency of starting and stopping the heat medium generator, and to moderate the rise and fall of the temperature of the heat medium accompanying the start and stop. Temperature control performance can be significantly improved. Moreover, the above effect can be achieved only by adding a bypass valve and a simple structure.

Further, according to the third aspect of the present invention, all of the heat medium can be made to flow to the customer side plant regardless of changes in the heat load on the customer side, so when the heat load becomes small. It is possible to surely exert the effects of reducing the frequency of starting and stopping the heat medium generator and improving the control performance of the heat medium temperature.

Therefore, the conventional supply plant does not require a small capacity machine that must be installed for a small load, which is advantageous in terms of equipment price and equipment installation space.

[Brief description of drawings]

FIG. 1 is a piping system diagram of a one-stage pump type cooling heat source plant which is an embodiment of a heat medium control device for an air conditioning heating source plant according to the present invention, and FIGS. 2 and 3 are other embodiments of the present invention. Piping system diagram showing an example, Fig. 4 is the system flow of the plant that performed simulation, No. 5
Fig. 6 is a model configuration diagram for simulating the system of Fig. 4, Figs. 6 and 7 are graphs showing temperature changes of each part due to simulation results, and Fig. 8 is a model parameter for simulation and flow rate of each part. FIG. 9 and FIG. 10 are piping system diagrams of a conventional example. 1 ... Refrigerator (heat medium generator), 2 ... Pump, 3 ...
Supply-side plant piping, 4 ... Customers, 5 ... Customer-side plant piping, 10 ... Customer-side bypass paths, 11 ...
Bypass valve, A ... Supply side plant, B ... Consumer side plant.

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Claims (3)

(57) [Scope of utility model registration request] 1. A piping of a supply-side plant equipped with a heat medium generator that generates a heat medium for cooling and heating and a pump that sends out the generated heat medium, and a consumer who consumes the heat quantity possessed by the heat medium in parallel. In the heat medium control device of the cooling and heating heat source plant, which is connected so as to form a circulation path for the heat medium, the pipe outside the cooling and heating heat source machine room is bypassed to an appropriate position of the piping outside the cooling and heating heat source machine room. A heat medium control device for a heating / cooling heat source plant, characterized in that a bypass is provided in the bypass and the opening / closing of the bypass is controlled according to the heat load on the consumer side. 2. The opening / closing condition of the bypass valve is set to open when the consumer-side heat load is less than or equal to the output lower limit value of the heat medium generator having the minimum capacity, and is closed when it is equal to or more than the output lower limit value.
The heat medium control device of the heating and cooling heat source plant according to. 3. The opening degree of the bypass valve is continuously controlled to control the delivery pressure from the supply side plant or the ultimate pressure at the end of the pipe of the customer side plant. The heat medium control device of the heating and cooling heat source plant according to.