JP7407502B2 - Cooling capacity measuring device - Google Patents

Description

The present invention relates to a cooling capacity measuring device that calculates the amount of cooling energy as the amount of cooling energy by a refrigerator in a chilled water system that supplies chilled water produced using a refrigerator to a chilled water load.

BACKGROUND ART A chilled water system is known that uses a refrigerator to cool water in a cold water tank and supplies the chilled water to a chilled water load (facility using chilled water). There are two types of chilled water systems: circulation specifications and flowing water specifications. In the circulating specification, the water in the cold water tank is circulated between the chilled water load and used for cooling (indirect use), and in the flowing water specification, the water in the chilled water tank is disposed of by the chilled water load (direct use).

In such a chilled water system, there are cases where it is desired to know the amount of cooling energy as the amount of cooling energy produced by the refrigerator . For example, if you are planning to update your chilled water system to a new one, you may want to know how much the cooling load is on the current system.

Conventionally, as disclosed in Patent Document 1 below, a cooling energy amount calculation device has been proposed for a system using a cooling tower instead of a refrigerator. This device includes a cooling water circulation path (2) comprising a cooling tower (1) and a heat exchange section (3), and cooling water in the cooling water circulation path (2) via the heat exchange section (3). The calculation means (9) calculates the temperature difference (T1, T2) and the cooling water flow rate (Q1) of the cooling water circulation path (2), the cooling energy amount (E1) is calculated.

In a chilled water system using a cooling tower, water is basically circulated between the cooling tower and the chilled water load. On the other hand, in the case of a chilled water system using a refrigerator, as mentioned above, there are not only circulation specifications but also running water specifications and a combination of both specifications. Furthermore, the timing at which cold water is supplied from the cold water tank to the chilled water load and the timing at which makeup water is supplied to the cold water tank do not necessarily coincide. Therefore, unless these circumstances are addressed, in a chilled water system using a refrigerator, the amount of cold heat as the amount of cooling energy by the refrigerator cannot be easily calculated.

JP2003-83818A (Claim 1, Paragraph 0014-0015)

The problem to be solved by the present invention is to provide a cooling capacity measuring device that can easily calculate the amount of cold energy as the amount of cooling energy produced by the refrigerator in a chilled water system that supplies chilled water produced using a refrigerator to a chilled water load. It's about doing.

In addition, in order to know the amount of cold heat as the amount of cooling energy by the refrigerator , it is necessary to detect the water temperature. However, in order to detect water temperature, removing the insulation from the piping and inserting a temperature sensor inside the pipe not only requires time and effort, but also requires stopping the chilled water system while the temperature sensor is being installed. be. Therefore, an object of the present invention is to detect the water temperature and make it possible to calculate the amount of cold energy without stopping the cold water system.

The present invention has been made to solve the above problem, and the invention according to claim 1 includes a cold water tank for storing water, a refrigerator for cooling the water stored in the cold water tank, and the cold water tank. It is applied to a chilled water system comprising a water supply channel that supplies water from the water to the chilled water load and whose water temperature inside the pipe can fluctuate in relation to the ambient temperature of the pipe while the water supply is stopped, and an inlet channel to the cold water tank. a first temperature sensor that detects water temperature; a second temperature sensor that detects the water temperature of the inlet waterway; a temperature detected by the first temperature sensor while water is flowing through the water supply channel; a cold energy amount calculation unit that calculates the amount of cold energy as the amount of cooling energy by the refrigerator based on the temperature detected by the two temperature sensors and the water flow rate of the water supply channel and/or the inlet water channel; The calculation unit is a cooling capacity measuring device that calculates the amount of cooling energy using the temperature after a predetermined time has elapsed from the start of water flow as the temperature detected by each of the temperature sensors, The cold water sent to the cold water load is not returned to the cold water tank, and make-up water can be supplied to the cold water tank via the water inlet so as to maintain the water level in the cold water tank within a set range, and A flow rate sensor is provided in the water supply channel and/or the inlet channel, and the refrigerator controls the water supplied from the inlet channel and stored in the cold water tank to a temperature lower than the temperature detected by the second temperature sensor. The cooling energy amount calculation unit calculates the temperature detected by the first temperature sensor while water is flowing through the water supply channel, the temperature detected by the second temperature sensor while water is flowing through the water supply channel, and the temperature detected by the flow rate sensor. The cooling capacity measuring device is characterized in that the amount of cooling energy is calculated based on the flow rate .

According to the invention described in claim 1, the temperature of the water to the cold water load flowing through the water supply channel, the temperature of the water flowing to the cold water tank while flowing through the inlet channel, and the water flow rate of the water supply channel and/or the inlet channel. Based on this, the amount of cold energy as the amount of cooling energy by the refrigerator is calculated. By calculating based on the temperature of water flowing through each flow path , the amount of cooling heat can be easily calculated even in a running water specification (direct application).

According to the invention described in claim 1 , the cold water sent from the cold water tank to the cold water load via the water supply channel is not returned to the cold water tank, but the inlet channel is Make-up water can be supplied to the cold water tank via. In this case, the timing at which cold water is supplied from the cold water tank to the chilled water load and the timing at which makeup water is supplied to the cold water tank do not necessarily coincide. However, based on the water temperature to the cold water load flowing through the water supply channel, the water temperature to the cold water tank while flowing through the inlet channel, and the water flow rate of the water supply channel and/or the inlet channel, the amount of cooling energy by the refrigerator is The amount of cooling energy can be easily calculated. In other words, even with running water specifications, the amount of cooling heat can be easily calculated.

The invention according to claim 2 is the cooling capacity measuring device according to claim 1 , wherein each of the temperature sensors detects the temperature of the outer surface of the pipe.

According to the second aspect of the invention , the water temperature can be determined from the temperature of the outer surface of the pipe. Therefore, there is no need to insert a temperature sensor into the pipe. Furthermore, even if a heat insulating material is attached to the pipe, if the temperature sensor is inserted through the gap in the heat insulating material, there is no need to remove the heat insulating material on a large scale. Furthermore, there is no need to shut down the chilled water system for the installation of the temperature sensor.

The invention according to claim 3 determines whether or not water flows through the water supply channel based on whether or not a pump or valve provided in the water supply channel is operated; 3. The cooling capacity measuring device according to claim 1 or 2, wherein the cooling capacity measuring device determines whether or not water is flowing through the inlet waterway.

According to the third aspect of the invention , the amount of cold heat can be easily calculated by determining whether or not water is flowing in the water supply channel or the inlet channel based on whether or not the pump or valve is operating.

The invention according to claim 4 provides a method for calculating the load on cold water by using a weighted average weighted with the flow rate, based on the water temperature at each predetermined time during each water flow and the flow rate flowing during that time for the water supply channel and the inlet channel. 4. The cooling capacity measuring device according to claim 1, wherein the cooling capacity measuring device calculates an average water supply temperature and an average water supply temperature to a cold water tank, and calculates the amount of cold energy based on the calculated average water supply temperature. .

According to the fourth aspect of the invention , by calculating the water temperature by a weighted average taking into account the flow rate, even when the change in flow rate is large, it is possible to accurately calculate the amount of cooling heat taking into account the change in flow rate.

Furthermore, the invention according to claim 5 monitors the amount of power used by the refrigerator or the chilled water system, and calculates the coefficient of performance of the chilled water system based on the amount of cold heat and the amount of power used within a predetermined time. The cooling capacity measuring device according to any one of claims 1 to 4, characterized in that:

According to the invention set forth in claim 5 , the coefficient of performance of the chilled water system can be calculated based on the amount of cooling heat and the amount of power used within a predetermined time.

According to the cooling capacity measuring device of the present invention, in a chilled water system that supplies chilled water produced using a chiller to a chilled water load, the amount of cold heat as the amount of cooling energy by the chiller can be easily calculated. Furthermore, it is possible to reduce labor and cost, and also to detect the water temperature and calculate the amount of cold energy without stopping the cold water system.

1 is a schematic diagram showing an example of a chilled water system to which a cooling capacity measuring device according to an embodiment of the present invention is applied.

Hereinafter, specific embodiments of the present invention will be described in detail based on the drawings.
FIG. 1 is a schematic diagram showing an example of a chilled water system 2 to which a cooling capacity measuring device 1 according to an embodiment of the present invention is applied.

The cold water system 2 of this embodiment includes a cold water tank 3 that stores water, a refrigerator 4 that cools the water stored in the cold water tank 3, and a cold water load (chilled water usage equipment) 5 (5A, 5B) from the cold water tank 3. A water supply channel 6 to the cold water tank 3 and an inlet channel 7 to the cold water tank 3 are provided.

The cold water tank 3 is a tank that stores water. The cold water tank 3 is provided with a water level sensor 8, which is capable of detecting the water level within the cold water tank 3.

In the illustrated example, the refrigerator 4 has an evaporator 4a installed in the cold water tank 3. The refrigerant and water exchange heat in the evaporator 4a, allowing the water in the cold water tank 3 to be cooled. However, the water in the cold water tank 3 may be circulated between the evaporator 4a outside the cold water tank 3 and cooled.

A water pump 9 is provided in the water supply channel 6 . By controlling the start and stop of the water pump 9, it is possible to control whether or not water is supplied to the cold water load 5. However, depending on the case, the flow rate of water supplied to the cold water load 5 may be adjustable by controlling the rotation speed of the water pump 9 or adjusting the opening degree of the water supply valve provided in the water supply channel 6.

The inlet waterway 7 is provided with a water inlet valve 10. By controlling the opening and closing of the water inlet valve 10, it is possible to control whether or not water is supplied to the cold water tank 3. However, depending on the case, the opening degree of the water inlet valve 10 may be adjusted to adjust the flow rate of water supplied to the cold water tank 3. Furthermore, instead of or in addition to the water inlet valve 10, a water inlet pump may be installed and its start/stop or rotation speed may be controlled. As will be described later, by controlling the water inlet valve 10 (and/or the water inlet pump) based on the detection signal of the water level sensor 8, the water level inside the cold water tank 3 is maintained at the set level. Alternatively, a ball tap may be used, depending on the case.

The chilled water system 2 further includes a controller 11 . The controller 11 is connected to the water pump 9, the water inlet valve 10, the water level sensor 8, and the like. The controller 11 controls the water inlet valve 10 based on the detection signal of the water level sensor 8 to maintain the water level in the cold water tank 3 at a set water level (set range). Further, the water supply pump 9 is controlled based on the cold water request signal from the cold water load 5, so that the cold water in the cold water tank 3 can be supplied to the cold water load 5. However, in addition to controlling the water pump 9 based on the cold water request signal from the cold water load 5, the water pump 9 may be controlled based on the pressure of the water channel 6 from the water pump 9 to the cold water load 5. That is, when cold water is used in the cold water load 5, the pressure in the water supply channel 6 downstream of the water pump 9 decreases, so the water pump 9 may be controlled based on the pressure change. Note that the water stored in the cold water tank 3 is maintained at a set temperature (set range) by the refrigerator 4.

In FIG. 1, the water supply channel 6 shown by a solid line shows the case of running water specifications (direct use). In this case, the cold water in the cold water tank 3 is supplied to the cold water load 5A via the water supply channel 6, is not returned to the cold water tank 3, and is disposed of.

In FIG. 1, the configuration in which a recirculation path 12 is added (the cold water load is 5B instead of 5A) shown by the two-dot chain line indicates a case of circulation specifications (indirect use). In this case, the cold water in the cold water tank 3 is supplied to the cold water load 5B via the water conduit 6, and the cold water load 5B uses the cold energy (that is, exchanges heat between the object to be cooled and the cold water to cool the object. After the cold water is heated (temperature raised), it is returned to the cold water tank 3. In the case of circulation specification, the return flow path 12 functions as the inlet waterway 7.

In FIG. 1, in addition to the return flow path 12 shown by the two-dot chain line, the configuration in which the water supply channel 13 shown by the one-dot chain line is also added indicates a case of a combined specification of flowing water specification and circulation specification. In this case, after the cold water in the cold water tank 3 passes through the water supply channel 6, a part of it is returned to the cold water tank 3 via the reflux channel 12, and the remaining part is disposed of via the water supply channel 13 as a cold water load 5A. An amount of make-up water corresponding to the amount that has been discarded is replenished from the inlet waterway 7 by opening the water inlet valve 10 as appropriate.

In the illustrated example, the return flow path 12 from the cold water load 5B is connected to the inlet waterway 7 downstream of the water inlet valve 10, but it may be connected to the cold water tank 3. That is, in the illustrated example, the return flow path 12 and the inlet waterway 7 are made into a common pipe line on the cold water tank 3 side, but they may be connected to the cold water tank 3 separately. In other words, the make-up water to the cold water tank 3 via the inlet channel 7 may be supplied to the cold water tank 3 via the return route 12 or may be supplied to the cold water tank 3 without going through the return route 12. good.

Next, the cooling capacity measuring device 1 of this embodiment will be specifically explained.
The cooling capacity measuring device 1 includes a cooling energy amount calculation means (cooling energy amount calculation unit) 14 that calculates the amount of cooling energy as the amount of cooling energy by the refrigerator 4 for the chilled water load 5 (5A, 5B). Moreover, the chilled water system 2 is provided with various sensors described below. Then, the cooling energy amount calculation means 14 calculates the amount of cooling energy as the amount of cooling energy by the refrigerator 4 for the chilled water load 5 based on the detection signals of each sensor, elapsed time, and the like.

Although not shown, the cooling energy calculation means 14 includes an input section for performing various inputs and settings, a storage section for registering detection information from each sensor along with date and time (or elapsed time), and a storage section for registering the detection information from each sensor along with the date and time (or elapsed time), etc. It includes a calculation section that performs various calculations described later based on the contents of the storage section, and an output section that outputs the calculation results.

The cooling energy amount calculating means 14 may be configured to include the controller 11 of the chilled water system 2 (or configured to be included in the controller 11 of the chilled water system 2) as shown in the illustrated example; The controller 11 may be configured separately. For example, it may be configured from various terminals such as a personal computer or a tablet. In that case, the signals etc. from each sensor are once registered in a recording means (for example, a data logger), and the recorded information of the recording means is imported into the storage section via an information recording medium, wired or wireless, and processed. Good too. Hereinafter, an example of calculation by the cooling energy amount calculating means 14 will be explained.

≪(a) Circulation specification≫
In the circulating cold water system 2, as described above, the cold water from the cold water tank 3 is sent to the cold water load 5B via the water supply channel 6, and after releasing cold heat, is returned to the cold water tank 3 via the reflux channel 12. It will be done. In this case, the return flow path 12 to the cold water tank 3 becomes the inlet water channel 7 to the cold water tank 3. Furthermore, while water is flowing through the water supply channel 6, water is also flowing through the return flow channel 12.

In the circulating cold water system 2, the first temperature sensor 15 is provided in the water supply channel 6, and the second temperature sensor 16 is provided in the return flow channel 12. The first temperature sensor 15 detects the temperature of cold water supplied to the cold water load 5B via the water supply channel 6, and the second temperature sensor 16 detects the temperature of the cold water returned to the cold water tank 3 via the return channel 12. To detect. Since cold water is used in the cold water load 5B, the temperature T2 detected by the second temperature sensor 16 is higher than the temperature T1 detected by the first temperature sensor 15 (T2>T1).

In the circulating cold water system 2, the water supply channel 6 is provided with a first flow rate sensor 17. However, since the entire amount of water supplied via the water supply channel 6 is returned to the cold water tank 3 via the reflux channel 12, the first flow rate sensor 17 may be provided in the reflux channel 12 instead of the water supply channel 6.

During operation of the chilled water system 2, during a predetermined measurement period, the temperature T1 detected by the first temperature sensor 15 while water is flowing through the water supply channel 6, and the temperature T1 detected by the first temperature sensor 15 when water is flowing through the return channel 12 (here, it can be said to be the inlet channel 7 as described above). The temperature T2 detected by the second temperature sensor 16 and the water flow rate Q1 detected by the first flow rate sensor 17 during the period are determined, and these pieces of information are registered in the storage section of the cooling energy amount calculating means 14. Then, based on the instruction from the input section, the calculation section calculates the amount of cooling energy E1 used by the chilled water load 5B based on the following equation. The amount of cold energy E1 used by the cold water load 5B can also be said to be the amount of cooling energy by the refrigerator 4.

In addition, when water is not constantly flowing through the water supply channel 6 (and by extension, the return flow channel 12), the calculation is performed based on the water temperatures T1 and T2 at the time of water flow. Whether or not water is flowing can be detected not only by the first flow rate sensor 17 but also by collecting operation signals of the water pump 9 (or water valve), for example. Then, by preferably continuously measuring the water temperature of the water supply channel 6 and the return channel 12, the operation signal, etc., and calculating the average temperature of the water during water flow (in other words, the average temperature only when cold water is used). ), the cooling energy amount E1 can be appropriately calculated. Immediately after water flow starts, the water inside the pipe and the temperature of the pipe wall are close to room temperature (ambient temperature). It is desirable to calculate the average water temperature during water flow (based on the water temperature after the standby time has elapsed).

[Math 1] E1=(T2-T1)×Q1

However, considering that the water flow rate and water temperature may change from moment to moment, the water supply channel 6 Calculate the average water supply temperature T1' to the cold water load 5B via the recirculation path 12 and the average return water temperature T2' (average water supply temperature to the cold water tank 3) from the chilled water load 5B via the return path 12, and based on these It is preferable to calculate the amount of cooling energy E1.

Specifically, the measurement period is divided into predetermined time intervals (n equal parts), and the flow rate detected by the first flow rate sensor 17 for each predetermined time period (water flow rate within the predetermined time period) is the first water flow rate Q11, The second water supply flow rate Q12, the third water supply flow rate Q13, ... the nth water supply flow rate Q1n, and the first temperature at a predetermined time within each predetermined time (for example, at the start or end of each predetermined time) or the average first temperature within the predetermined time. The temperature detected by the sensor 15 is the first water supply temperature T11, the second water supply temperature T12, the third water supply temperature T13, ... the nth water supply temperature T1n, and the temperature detected by the second temperature sensor 16 is the first water supply temperature (return water temperature). water temperature) T21, second inlet water temperature T22, third inlet water temperature T23, ... nth inlet water temperature T2n, the average water supply temperature T1' of the water supply channel 6 and the average return water temperature of the return channel 12 (cold water tank 3 The average water supply temperature) T2' is calculated as follows. In Equation 1, the amount of cooling energy E1 may be calculated by using T1' instead of T1 and using T2' instead of T2. At this time, Q1 is the total value of the water flow rate during the entire measurement period (Q1=Q11+Q12+...Q1n).

Note that there are flow rate sensors that measure instantaneous flow rate (flow rate per fixed time) and those that measure cumulative flow rate (accumulated flow rate up to now). When using an instantaneous flow rate sensor as the first flow rate sensor 17, the water flow rate per predetermined time can be determined by the sensor detection value itself, or the water flow rate per predetermined time can be determined by multiplying the sensor detection value by time. . On the other hand, when using an integrated flow rate sensor, the "flow rate detected by the first flow rate sensor 17 at each predetermined time period" refers to the difference in sensor detection value between the start and end of the predetermined time period (i.e., Each of the water supply flow rates Q11 to Q1n may be calculated as the difference in the cumulative flow rate. This also applies to the flow rate detected by the second flow rate sensor (each of the inlet water flow rates Q21 to Q2n), the flow rate detected by the third flow rate sensor (each of the return water flow rates Q31 to Q3n), etc., which will be described later. In short, the flow rate flowing during each predetermined time period may be determined.

[Math 2] T1'=(T11×Q11+T12×Q12+...T1n×Q1n)/(Q11+Q12+...Q1n)

[Math 3] T2'=(T21×Q11+T22×Q12+...T2n×Q1n)/(Q11+Q12+...Q1n)

≪(b) For running water specification≫
In the cold water system 2 with flowing water specifications, as described above, the cold water from the cold water tank 3 is sent to the cold water load 5A via the water supply channels 6 and 13, and is disposed of. In this case, installation of the reflux path 12 is unnecessary. Furthermore, the cold water tank 3 is replenished with make-up water via the inlet channel 7 in correspondence with the outflow from the cold water tank 3 via the water supply channel 6 . However, the timing at which cold water is supplied from the cold water tank 3 to the cold water load 5A and the timing at which makeup water is supplied to the cold water tank 3 do not necessarily coincide.

In the cold water system 2 with flowing water specifications, the first temperature sensor 15 is provided in the water supply channel 6 (13), and the second temperature sensor 16 is provided in the inlet channel 7. The first temperature sensor 15 detects the temperature of the cold water supplied to the cold water load 5A via the water supply channel 6, and the second temperature sensor 16 detects the temperature of the make-up water supplied to the cold water tank 3 via the inlet channel 7. Detect temperature. Since the water replenished from the inlet channel 7 is cooled by the refrigerator 4, the temperature T1 detected by the first temperature sensor 15 becomes lower than the temperature T2 detected by the second temperature sensor 16 (T2>T1).

In the cold water system 2 with flowing water specifications, the first flow rate sensor 17 is provided in the water supply channel 6 (13). Since the outflow from the water supply channel 6 is replenished from the inlet channel 7, a second flow rate sensor (not shown) may be provided in the inlet channel 7 instead of or in addition to installing the first flow rate sensor 17. . Although the timing of water outflow and water inflow to the cold water tank 3 is different, when viewed over a relatively long predetermined measurement period, the flow rate Q1 measured by the first flow rate sensor 17 and the flow rate Q2 measured by the second flow rate sensor are approximately the same (Q1≒ Q2). However, in order to achieve more accurate measurement (particularly when the water temperature in each flow path 6, 7 may change), both the first flow rate sensor 17 and the second flow rate sensor are provided, and the weight is applied as described below. Preferably, the average temperature is used.

In the case of running water specifications, processing can be performed in the same way as in the case of circulation specifications. That is, during operation of the chilled water system 2, during a predetermined measurement period, the temperature T1 detected by the first temperature sensor 15 while water is flowing through the water supply channel 6 (13), and the detection temperature T1 by the second temperature sensor 16 while water is flowing through the inlet channel 7. The temperature T2 and the water flow rate Q1 by the first flow rate sensor 17 (and/or the water flow rate Q2 by the second flow rate sensor) within the period are determined, and based on the above formula 1, the chiller for a cold water load of 5A is calculated. The amount of cooling energy E1 as the amount of cooling energy based on 4 is calculated.

Note that when water is not constantly flowing through the water supply channel 6 and the inlet channel 7, the calculation is performed based on the water temperatures T1 and T2 at the time of water flow. Whether or not water is flowing can be detected by the first flow rate sensor 17 or the like.For example, for the water supply channel 6, it can be detected by collecting the operating signal of the water pump 9 (or water supply valve), and for the inlet channel 7, it can be detected by collecting the operation signal of the water supply pump 9 (or water supply valve). It is also possible to collect and detect operation signals of the water inlet valve 10 (or water inlet pump). Then, by preferably continuously measuring the water temperature of the water supply channel 6 and the inlet channel 7, the operation signal, etc., and calculating the average temperature of the water flowing through each channel 6, 7, the amount of cooling energy E1 is calculated. can be calculated appropriately.

In addition, as in the case of circulation specifications, considering that the water flow rate and water temperature can change from moment to moment, the flow rate is weighted based on the water temperature at each predetermined time during water flow and the flow rate during that time. The average water supply temperature T1' to the cold water load 5A via the water supply channel 6 (13) and the average water supply temperature T2' to the cold water tank 3 via the inlet channel 7 are calculated by weighted averaging, and based on these, the temperature of the cold water is Preferably, the quantity E1 is calculated.

Specifically, it can be calculated based on Equation 2 and Equation 3 as in the case of the circulation specification. However, when a second flow rate sensor is provided in addition to the first flow rate sensor 17, the following expression is used instead of Equation 3. In other words, the flow rate detected by the second flow rate sensor at each predetermined time (water flow rate within a predetermined time) is the first water inflow flow rate Q21, the second water inflow flow rate Q22, the third water inflow flow rate Q23, ... the nth water inflow flow rate Q2n. , the temperature detected by the second temperature sensor 16 at a predetermined time within each predetermined time (for example, at the start or end of each predetermined time) or the average temperature detected within the predetermined time is the first water inlet temperature T21, the second water inlet temperature T22, and the second water inlet temperature T22. When the third inlet water temperature T23, .

[Math 3'] T2'=(T21×Q21+T22×Q22+...T2n×Q2n)/(Q21+Q22+...Q2n)

≪(c) For composite specifications≫
In the combined specification chilled water system 2, as described above, the chilled water from the chilled water tank 3 is sent to the chilled water load 5B via the water supply channel 6, a portion is returned to the chilled water tank 3 via the return channel 12, and the remainder is is disposed of via the water supply channel 13 with a cold water load of 5A.

In the combined cold water system 2, a first temperature sensor 15 is provided in the water supply channel 6, a second temperature sensor 16 is provided in the inlet channel 7, and a third temperature sensor 18 is provided in the return channel 12. In this case, in FIG. 1, the second temperature sensor 16 is provided in the inlet channel 7 on the upstream side of the confluence of the inlet channel 7 and the return channel 12 (that is, the position of the second temperature sensor 16 is different from that shown in the figure). ), a third temperature sensor 18 is provided in the reflux path 12 . The first temperature sensor 15 detects the temperature of cold water supplied to the cold water loads 5 (5A, 5B) via the water supply channel 6, and the second temperature sensor 16 detects the temperature of the cold water supplied to the cold water tank 3 via the inlet channel 7. The third temperature sensor 18 detects the temperature of the cold water returned to the cold water tank 3 via the recirculation path 12. Note that the detected temperature T2 of the second temperature sensor 16 is higher than the detected temperature T1 of the first temperature sensor 15 (T2>T1), and the detected temperature T3 of the third temperature sensor 18 is higher than the detected temperature T1 of the first temperature sensor 15. higher than T1 (T3>T1).

In the combined cold water system 2, the water supply channel 6 is provided with a first flow rate sensor 17, the water supply channel 13 and/or the inlet channel 7 is provided with a second flow rate sensor (not shown), and the return channel 12 is provided with a second flow rate sensor (not shown). is provided with a third flow rate sensor (not shown). However, since the flow rate of the water supply channel 6 = the flow rate of the water supply channel 13 (≒ the flow rate of the inlet channel 7) + the flow rate of the return flow channel 12, at least one of the first flow rate sensor 17, the second flow rate sensor, and the third flow rate sensor If two flow rate sensors are provided, it becomes possible to calculate the flow rates of all channels (flow rate Q1 of water supply channel 6, flow rate Q2 of water supply channel 13 or inlet channel 7, flow rate Q3 of return channel 12).

In the case of composite specifications, processing can be done in the same way as in the case of circulation specifications and running water specifications. Specifically, the relationship between the water supply channel 6 and the return channel 12 can be treated in the same manner as in the circulation specification, and the relationship between the water supply channel 13 and the inlet channel 7 can be treated in the same manner as in the flowing water specification. That is, during operation of the chilled water system 2, during a predetermined measurement period, the temperature T1 detected by the first temperature sensor 15 while water is flowing through the water supply channel 6, and the temperature T2 detected by the second temperature sensor 16 while water is flowing through the inlet channel 7. , the temperature T3 detected by the third temperature sensor 18 while water is flowing through the reflux path 12 is determined. Furthermore, flow rate sensors are installed in at least two of the water supply channel 6, water supply channel 13 (or inlet channel 7), and return flow channel 12 within the period, and water flow rates Q1, Q2, and Q3 are determined. Then, find the amount of cold energy E1a as the amount of cooling energy by the refrigerator 4 for the cold water load 5B of indirect use, and the amount of cold energy E1b as the amount of cooling energy by the refrigerator 4 for the cold water load 5A of direct use, The total amount of cooling energy E1 as the amount of cooling energy by the refrigerator 4 for each cold water load 5A, 5B is calculated. At this time, as in the case of the circulation specification and the flowing water specification, it is preferable to use the flow rate sensor or the operation signal of the pump or valve to adopt the water temperatures T1 to T3 during water flow.

[Math. 4] E1a=(T3-T1)×Q3

[Math 5] E1b=(T2-T1)×Q2

[Math 6] E1=E1a+E1b

However, as in the case of circulation specifications and flowing water specifications, taking into consideration that the water flow rate and water temperature can change from moment to moment, the flow rate is calculated based on the water temperature at each predetermined time during water flow and the flow rate during that time. The average water supply temperature T1' via the water supply channel 6, the average water supply temperature T2' via the water supply channel 13 (or the inlet channel 7), and the average water supply temperature T3' via the return channel 12 are determined by the weighted average. It is preferable to calculate the amounts of cooling energy E1a, E1b, and eventually E1 based on these.

Specifically, the flow rates detected by the first flow rate sensor 17 at predetermined time intervals are the first water supply flow rate Q11, the second water supply flow rate Q12, the third water supply flow rate Q13, ... the nth water supply flow rate Q1n, and the second flow rate sensor The detected flow rates are the first incoming water flow rate Q21, the second incoming water flow rate Q22, the third incoming water flow rate Q23, ... the nth incoming water flow rate Q2n, and the detected flow rates by the third flow rate sensor are the first return water flow rate Q31, the second incoming water flow rate Q31, It is assumed that the return water flow rate Q32, the third return water flow rate Q33, . . . the n-th return water flow rate Q3n. Further, the temperatures detected by the first temperature sensor 15 at a predetermined time within each predetermined time or on an average within a predetermined time are the first water supply temperature T11, the second water supply temperature T12, the third water supply temperature T13, ... the nth water supply temperature T1n. The temperatures detected by the second temperature sensor 16 are the first water inlet temperature T21, the second water inlet temperature T22, the third water inlet temperature T23, ... the nth inlet water temperature T2n, and the temperature detected by the third temperature sensor 18 is, It is assumed that the first returned water temperature T31, the second returned water temperature T32, the third returned water temperature T33, . . . the nth returned water temperature T3n. In this case, the average water supply temperature T1' of the water supply channel 6, the average inlet water temperature T2' of the inlet channel 7, and the average return water temperature T3' of the return channel 12 are calculated as follows. In Equations 4 and 5, the amounts of cooling energy E1a and E1b may be calculated by using T1' instead of T1, T2' instead of T2, and T3' instead of T3.

[Math. 7] T1'=(T11×Q11+T12×Q12+...T1n×Q1n)/(Q11+Q12+...Q1n)

[Math. 8] T2'=(T21×Q21+T22×Q22+...T2n×Q2n)/(Q21+Q22+...Q2n)

[Math. 9] T3'=(T31×Q31+T32×Q32+...T3n×Q3n)/(Q31+Q32+...Q3n)

As is clear from the above, according to the cooling capacity measuring device 1 of the present embodiment, the cold water The amount of cooling energy as the amount of cooling energy by the refrigerator 4 for the load 5 (5A, 5B) can be calculated. By calculating based on the water temperature flowing through each flow path, the amount of cooling energy can be calculated regardless of whether it is a circulation specification (indirect application), a flowing water specification (direct application), or a combination of these specifications. It can be easily calculated.

By the way, in the above embodiment, each temperature sensor 15, 16, 18 not only directly detects the water temperature in the pipe by inserting the detection part into the pipe, but also indirectly detects the temperature on the outside surface of the pipe. The water temperature may also be detected (estimated). In that case, there is no need to insert temperature sensors 15, 16, 18 into the pipes. Further, even if a heat insulating material is attached to the pipe, if the temperature sensors 15, 16, and 18 are inserted through the gap between the heat insulating material of the pipe, there is no need to remove the heat insulating material on a large scale. Furthermore, there is no need to stop the chilled water system 2 in order to attach the temperature sensors 15, 16, 18.

Furthermore, in the embodiment described above, whether or not water is flowing through each of the channels may be detected in the following manner instead of providing a flow sensor or a flow meter. That is, as described above, the presence or absence of water flow through the water supply channel 6 can be determined based on whether or not the water supply pump 9 or the water supply valve provided in the water supply channel 6 is in operation, or whether the water inlet pump or water inlet valve 10 provided in the water supply channel 7 is activated or not. Depending on the presence or absence of operation, it may be determined whether or not water is flowing through the inlet channel 7. The same applies to the reflux path 12, but in the case of circulation specifications, whether or not water is flowing through the reflux path 12 can be determined based on whether or not the water pump 9 or the water valve is operated. Note that when each temperature is calculated using the weighted average described above, the average temperature during water flow can be calculated without detecting whether or not the pump or valve is in operation, since the flow rate is used as a weight in the calculation.

Furthermore, the cooling capacity measuring device 1 has a function of determining the amount of power used by the refrigerator 4 or the chilled water system 2, and calculating the coefficient of performance of the chilled water system 2 based on the amount of cooling heat and the amount of power used within a predetermined time. You can leave it there. The coefficient of performance COP is calculated using the following formula.

[Math. 10] Coefficient of performance COP = Cold heat (kW) / Heat input (kW) = Flow rate x ΔT (outlet temperature - inlet temperature) / input power

For example, in a flowing water specification (the same applies to circulation specifications, etc.), the amount of cold water (both the water supply amount and the incoming water amount), the average outlet water temperature (the water temperature of the water supply channel 6) and the average inlet water temperature (the water temperature of the inlet channel 7) for the cold water tank 3, water temperature) can be calculated as described above. In particular, it is preferable to obtain the average outlet water temperature and the average inlet water temperature as the aforementioned weighted average rather than a simple arithmetic average. The required amount of heat (J/period) within a predetermined measurement period (for example, one week (7 days x 24 hours)) can be calculated as: amount of cold water x (average inlet temperature - average outlet temperature) x specific heat of water. From this, the average required amount of heat (in kj/h or even kW) can be calculated. On the other hand, the average power (kW) during operation of the entire chilled water system 2 (or the refrigerator 4 (and water pump 9) which is the main part of power consumption) is determined by the current value (preferably further voltage value) of the refrigerator 4, for example. , is determined by measuring the current value (preferably further voltage value) of the water pump 9. Then, the coefficient of performance COP can be calculated from the average power during operation and the average required heat amount based on the following formula. Note that here, one week is taken as an example of the measurement period, but the measurement period may be longer or shorter than this. For example, the amount of cooling energy or COP for several hours or one day may be determined. In that case, it is possible to know the amount of cooling energy and COP at the peak time when the cooling load rapidly increases.

[Math. 11] COP = average required heat amount / average power during operation

The cooling capacity measuring device 1 of the present invention is not limited to the configuration (including control) of the embodiment described above, and can be modified as appropriate. In particular, a cold water tank 3 that stores water, a refrigerator 4 that cools the water stored in the cold water tank 3, a water supply channel 6 from the cold water tank 3 to the cold water load 5, and an inlet channel 7 to the cold water tank 3. (a) a first temperature sensor 15 that detects the water temperature of the water supply channel 6; (b) a second temperature sensor 16 that detects the water temperature of the inlet channel 7; and (c) a Based on the temperature detected by the first temperature sensor 15 while water is flowing through the waterway 6, the temperature detected by the second temperature sensor 16 while water is flowing through the inlet waterway 7, and the flow rate of water through the waterway 6 and/or the inlet waterway 7, cold water is cooled. As long as it includes a cold energy amount calculation unit 14 that calculates the amount of cold energy as the amount of cooling energy by the refrigerator 4 for the load 5, other configurations can be changed as appropriate.

For example, in the embodiment described above, the water stored in the cold water tank 3 can be circulated between the water and the evaporator 4a of the refrigerator 4, and when water is sent to the cold water load 5, it is sent out through the evaporator 4a. It may be configured as follows. In that case, the same control is possible by monitoring the temperature and flow rate of water supplied to the cold water load 5.

Further, in the embodiment described above, it is preferable that the first temperature sensor 15 is provided at a position where the pipe temperature does not rise due to heat input from the shaft power when the water pump 9 is in closed/closed operation.

1 Cooling capacity measuring device 2 Chilled water system 3 Chilled water tank 4 Freezer (4a: evaporator)
5 (5A, 5B) Chilled water load 6 Water supply channel 7 Inlet channel 8 Water level sensor 9 Water pump 10 Water inlet valve 11 Controller 12 Return path 13 Water supply channel 14 Cold heat amount calculation means 15 First temperature sensor 16 Second temperature sensor 17 First Flow rate sensor 18 Third temperature sensor

Claims (5)

A cold water tank that stores water, a refrigerator that cools the water stored in this cold water tank, water is sent from the cold water tank to the cold water load, and the water temperature inside the pipe may fluctuate depending on the ambient temperature of the pipe while the water supply is stopped. applied to a cold water system comprising a water supply channel and an inlet channel to the cold water tank;
a first temperature sensor that detects the water temperature of the water supply channel;
a second temperature sensor that detects the water temperature of the inlet waterway;
Based on the temperature detected by the first temperature sensor while water is flowing through the water supply channel, the temperature detected by the second temperature sensor while water is flowing through the water supply channel, and the flow rate of water through the water supply channel and/or the water supply channel, A cold energy amount calculation unit that calculates a cold energy amount as a cooling energy amount by the refrigerator,
The cooling energy amount calculation unit is a cooling capacity measuring device that calculates the cooling energy amount using a temperature after a predetermined time has elapsed from the start of water flow as the temperature detected by each of the temperature sensors,
The cold water sent from the cold water tank to the cold water load via the water supply channel is not returned to the cold water tank,
Makeup water can be supplied to the cold water tank via the inlet water channel so as to maintain the water level in the cold water tank within a set range,
A flow rate sensor is provided in the water supply channel and/or the inlet channel,
The refrigerator cools water supplied from the water inlet and stored in the cold water tank to a temperature lower than the temperature detected by the second temperature sensor,
The cooling energy amount calculation unit is based on the temperature detected by the first temperature sensor while water is flowing through the water supply channel, the temperature detected by the second temperature sensor while water is flowing through the water supply channel, and the flow rate detected by the flow rate sensor, Calculate the amount of cold heat
A cooling capacity measuring device characterized by: The cooling capacity measuring device according to claim 1 , wherein each of the temperature sensors detects the temperature of the outer surface of the pipe. Determining whether or not water flows through the water supply channel based on whether or not a pump or valve provided in the water supply channel operates;
The cooling capacity measuring device according to claim 1 or 2, wherein whether or not water is flowing through the inlet waterway is determined based on whether or not a pump or a valve provided in the inlet waterway is operated. Regarding the water supply channel and the inlet channel, the average temperature of the water supplied to the chilled water load and the temperature of the water to the chilled water tank are determined by a weighted average weighted by the flow rate, based on the water temperature at each predetermined time during each water flow and the flow rate during that time. The cooling capacity measuring device according to any one of claims 1 to 3, wherein the cooling capacity measuring device calculates an average water supply temperature and calculates the amount of cooling energy based on this. Monitoring the amount of electricity used by the refrigerator or the chilled water system,
The cooling capacity measuring device according to any one of claims 1 to 4, wherein a coefficient of performance of the chilled water system is calculated based on the amount of cooling heat and the amount of electricity used within a predetermined time.

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