JP2008215680A - Cold medium refrigerating/freezing equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide air conditioning equipment capable of elongating a yearly free cooling operation time. <P>SOLUTION: This cold medium refrigerating/freezing equipment comprises a heat storage water tank for storing cold water, a cooling water circulation passage comprising a group of freezers, a cooling tower and a pump, a cooling water circulation passage for free cooling, comprising a cooling tower and a pump, a heat exchanger for exchanging heat between the cooling water in the cooling water circulation passage and the water in the heat storage water tank, a heat exchanger for exchanging heat between the cooling water in the cooling water circulation passage for free cooling and the water in the heat storage water tank, a cooling circuit for free cooling, comprising a cooling tower and a pump, and connected with a going-way of the cooling water circulation passage for free cooling to cool the cooling water of the cooling water circulation passage for free cooling, a switching mechanism disposed between the cooling water circulation passage for free cooling and the cooling circuit for free cooling, and connecting the cooling water circulation passage for free cooling and the cooling circuit for free cooling in series, and a control device for controlling the switching of the switching mechanism. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cooling water cooling refrigeration facility, and cools and refrigerates cooling water used for exothermic cooling in various processes and cooling water for air conditioning facilities using only a cooling tower without using a refrigerator (free cooling). ) It relates to a technology for extending the period.

  Heaters and heating furnaces using high frequency dielectric heating in semiconductor production equipment need cooling with cooling water throughout the year. The cooling water supply temperature is set to a temperature of about 20 ° C., which is lower than room temperature and below the dew point of room air so that condensation does not occur in order to keep the thermal environment of the apparatus and the product good. Although the cooling water is basically cooled by a refrigerator regardless of the set temperature, the cooling tower is used to save energy when the outdoor wet-bulb temperature is low and the cooling water supply temperature is relatively high in winter. Some cooling water production was possible (hereinafter referred to as free cooling).

As shown in FIG. 11, in the conventional open-type cooling tower heat storage system, a heat storage water tank 10 is provided for supplying cold water of 20 ° C. to the production apparatus group 13, and cold water is supplied to the production apparatus group 13 via the cold water supply pipe 11. And a chilled water return pipe 12 for returning the chilled water whose temperature has risen to the production device group 13 to the uppermost stream of the heat storage water tank 10 is installed.
In order to cool the water in the heat storage water tank 10, heat exchange is performed with the water in the refrigerating machine group 14, the pump CP1 for supplying water to the refrigerating machine evaporator, the cooling tower CT1 of the auxiliary machinery, the pump P1, and the heat storage water tank 10. A pump CP2 for sending water in the heat exchanger 15 and the heat storage water tank 10 to the heat exchanger 15 is installed. Moreover, the outlet pipe 17 of the cold water cooled by the heat exchanger 15 is arranged on the pumping position side of the pump P5 that sends the cold water to the production apparatus group 13. Moreover, the hot water temperature T3 measurement sensor which measures the water supply temperature of a water tank is provided in the pumping up side of the pump P5. The heat storage water tank 10 can attach the temperature ranking of the content water on the right and left of the figure by a borer weir not shown or a communication pipe arranged in an appropriate route.

  In order to cool the water in the heat storage water tank 10 in winter, the free cooling cooling tower CT3, the auxiliary pump P3, and the free cooling heat exchanger 16 and the heat storage water tank for exchanging heat with the water in the heat storage water tank 10 are used. A pump P4 for sending the water in 10 to the heat exchanger 16 for free cooling is installed. Moreover, the exit pipe | tube 18 of the cold water cooled with the heat exchanger 16 for free cooling is arrange | positioned at the cold water return pipe | tube side heated from the production apparatus group 13. FIG. In addition, an intermediate temperature T2 measuring sensor for measuring the intermediate temperature of the water tank is provided downstream of the cold water outlet pipe 18.

  In this example, the cooling water circulation path 21 for free cooling is composed of a cooling tower CT3 for free cooling and a pump P3 for auxiliary equipment, and the cooling water for the cooling tower CT3 for free cooling is free cooled by the pump P3. And a return path 21b for returning the cooling water heat-exchanged by the free-cooling heat exchanger 16 to the free-cooling cooling tower CT3.

Next, based on FIG. 12, operation | movement of the conventional open type cooling tower thermal storage system is demonstrated.
First, the refrigerator group 14, the fan of the cooling tower CT1, the pump P1, the pumps CP1 and CP2 are operated, and the control by the temperature controller TIC1 is started so that the water supply temperature T3 of the heat storage water tank 10 becomes the set temperature 20 ° C. ( Step S100).
Next, the operation of the pump P5 is started (step S101).

  Next, the outside air wet bulb temperature T1 measured by the outside air wet bulb thermometer is input to the cooling tower controller 20. The controller 20 determines whether or not the outdoor wet bulb temperature T1 is less than 5 ° C. (step S102). If the outside air wet bulb temperature T1 is 5 ° C. or higher, this step is stopped until the outside air wet bulb temperature T1 becomes 5 ° C. or lower. When the outdoor wet bulb temperature T1 is less than 5 ° C., the process proceeds to step S103.

Next, when the outside air wet bulb temperature T1 is less than 5 ° C., the fan of the cooling tower CT3 for free cooling is operated, and the pump P3 and the pump P4 are operated (step S103).
Next, it is determined whether or not the cooling water temperature T4 of the cooling tower CT3 for free cooling is less than 5 ° C. (step S104). When the cooling water temperature T4 is lower than 5 ° C., the fan of the cooling tower CT3 for free cooling is stopped (step S105). If the cooling water temperature T4 is 5 ° C. or higher, the process returns to step S102.

Next, it is determined whether or not the intermediate temperature T2 of the heat storage water tank 10 is less than 18 ° C. (step S106). If the intermediate temperature T2 is less than 18 ° C., the pump 4 is stopped (step S107). If the intermediate temperature T2 is 18 ° C. or higher, the process returns to step S105.
Next, it is determined whether or not the cooling water temperature T4 of the cooling tower CT3 for free cooling is 5 ° C. or higher (step S108). When the cooling water temperature T4 is less than 5 ° C., the process returns to step S105. When the cooling water temperature T4 of the cooling tower CT3 for free cooling is 5 ° C. or higher, the process proceeds to step S109.

Next, it is determined whether or not the outdoor wet bulb temperature T1 is 5 ° C. or higher (step S109). When the outdoor wet bulb temperature T1 is less than 5 ° C., the process returns to step S103. When the outdoor wet bulb temperature T1 is 5 ° C. or higher, the process proceeds to step S110.
Next, the fan, the pump P3, and the pump P4 of the cooling tower CT3 for free cooling are stopped (step S110).

Next, it is determined whether to stop the pump P5 (step S111). When stopping, it progresses to step S112. When not stopping, it returns to step S102.
Next, the refrigerator group 14, the fan of the cooling tower CT1, and the pumps P1, CP1, CP2 are stopped (step S112).
As described above, the conventional open-type cooling tower heat storage system stops operating.

Next, the operation of the conventional open-type cooling tower heat storage system in summer and intermediate periods will be described. Here, the outdoor wet bulb temperature was 13 ° C or higher in summer (4360 hours per year for Tokyo weather data), and the outdoor wet bulb temperature was 5 ° C or higher and less than 13 ° C (2100 hours per year for Tokyo meteorological data) in the intermediate period. .
In this season, when the cooling in the cooling tower CT3 becomes the outdoor wet bulb temperature T1 that cannot be cooled below the set water temperature of 18 ° C., the free cooling cooling tower CT3 and the pump P3 are stopped, and the free cooling heat exchanger 16 is used. The pump P4 that sends the water in the heat storage water tank 10 is also stopped. The means for cooling the cold water on the production device group 13 side operates the refrigerator group 14, the cooling tower CT 1, the pumps CP 1 and P 1, and the water in the heat storage tank 10 is cooled by the 7 ° C. cold water cooled by the refrigerator group 14. It conveys with pump CP2, and cools to 20 degreeC with the heat exchanger 15. FIG. The water cooled to 20 ° C. is sent to the production device group 13 by the pump P5 in the heat storage water tank 10, and the water heated by the production device group 13 is returned to the heat storage water tank 10 and cooled again by the heat exchanger 15. Is done. When the water supply temperature T3 in the heat storage tank 10 becomes 20 ° C. or less, the cold water between the refrigerator group 14 and the heat exchanger 15 starts a bypass operation by the three-way valve 19, and when the water temperature still falls below the set water temperature, the refrigerator group 14 To stop.

Next, the winter operation for free cooling will be described. Here, the outdoor wet bulb temperature was less than 5 ° C. in winter (2300 hours per year in Tokyo weather data).
In this season, the set temperature of the cooling water becomes the outside air wet bulb temperature T1 of 18 ° C. or less, so the cooling tower CT3 and the pumps P3 and P4 are operated and the cooling water of 18 ° C. cooled by the cooling tower CT3 for free cooling. The water in the heat storage water tank 10 is cooled to 20 ° C. by the heat exchanger 16 for free cooling. The water cooled to 20 ° C. is sent to the production device group 13 by the pump P5 in the heat storage water tank 10, and the water heated by the production device group 13 is returned to the heat storage water tank 10 to exchange heat again for free cooling. Cooled by the vessel 16. The remaining load that cannot be cooled in the cooling tower CT3 is processed by freezing of the refrigerator group as in the summer and intermediate periods.

Below, the technology (patent documents 1 and 2) which switches and operates a refrigerator and a cooling tower, and the above-mentioned conventional example differ in the position with respect to the heat storage water tank of each piping by the use of a heat storage water tank differing The parallel operation technique (patent document 3) with a group and the cooling water circulation path for free cooling is shown as a prior example.
JP-A-4-208332 JP 63-306358 A JP-A 62-196534

  In the intermediate period, the outdoor wet bulb temperature T1 becomes high, and cold water of 18 ° C. or lower cannot be produced. This period was longer than the operable winter time, and the free cooling equipment was not operating effectively. During periods when free cooling is not possible, energy is required to refrigerate cold water by operating compression and absorption chillers, so energy free operation is not an annual operation, and the use of free cooling equipment at the corner is annual There is a problem that it is short.

In the cooling tower with the capacity selected according to the rated capacity of the cooling tower for the centrifugal chiller, the heat load cooled by the cooling tower CT3 for free cooling is used to cool the cooling water having a water temperature of 23 ° C. to 18 ° C. It was necessary for the sphere temperature T1 to be 5 ° C. or lower. The free-cooling time at that time is as short as 2300 hours per year in the Tokyo climate.
Since the compressor of the refrigerator group 14 is used during the time when free cooling cannot be performed, a large amount of power consumption energy is required.

  The present invention has been made to solve such a conventional problem, and an object of the present invention is to provide a cooling medium cooling refrigeration facility having a long free cooling operation time.

  The invention according to claim 1 is for free cooling comprising a heat storage water tank for storing cold water, an outside air wet bulb thermometer, a cooling water circuit including a refrigerator group, a cooling tower and a pump, and a cooling tower and a pump. A cooling water circulation path, a heat exchanger that exchanges heat between the cooling water in the cooling water circulation path and the water in the heat storage water tank, the cooling water in the cooling water circulation path for free cooling, and the water in the heat storage water tank A free-cooling cooling system that includes a heat exchanger that exchanges heat with each other, a cooling tower, and a pump, and that is connected to an outward path of the free-cooling cooling water circuit and cools the cooling water in the free-cooling cooling water circuit A free cooling cooling water circuit and the free cooling cooling circuit, and the free cooling cooling water circuit and the free cooling cooling circuit are connected in series. A switching mechanism, characterized in that a control device for performing switching control of the switching mechanism.

  The invention according to claim 2 is the cooling medium cooling refrigeration facility according to claim 1, wherein the switching mechanism is connected between connection parts of the free cooling cooling circuit connected to the forward path of the cooling water circulation path for free cooling. A first valve provided, a second valve provided in the intake path of the cooling circuit for free cooling, and a third valve provided in a feed path of the cooling circuit for free cooling, The control device closes the first valve, the second valve, and the third valve when the outdoor wet bulb temperature measured by the outdoor wet bulb thermometer is equal to or higher than a first set value, or free. Stop the pump provided in the cooling water circulation path for cooling and the pump provided in the cooling circuit for free cooling, and the outdoor wet bulb temperature measured by the outdoor wet bulb thermometer is lower than the first set value and the second When the set value is exceeded, the first valve is closed, the second valve and the third valve are opened, the cooling tower and pump of the cooling water circulation path for free cooling, and the cooling circuit for free cooling A cooling tower and a pump are connected in series, and each device is operated to cool the cooling water in the cooling water circulation path for free cooling in two stages, and cooling water is supplied to the free cooling heat exchanger. When the outside air wet bulb temperature measured by the outside air wet bulb thermometer is lower than the second set value, the cooling tower and the pump of the cooling circuit for free cooling are stopped, The second valve and the third valve are closed, and the cooling water is conveyed to the free cooling heat exchanger via the free cooling cooling water circulation path. And performing control that.

  The invention according to claim 3 includes an outdoor wet bulb thermometer, a cooling water circulation path including a refrigerator group, a cooling tower and a pump, a cooling water circulation path for free cooling including a cooling tower and a pump, and production. A chilled water return pipe having a heat load such as a device and a pump, a cooling water in the cooling water circulation path, a cooling water in the cooling water circulation path for free cooling, and a chilled water in the cooling water return pipe are received or sent out. Free cooling cooling system comprising a heat storage water tank or a forward header and a return header, a cooling tower and a pump, and connected to an outward path of the free cooling cooling water circulation path to cool the cooling water in the free cooling cooling water circulation path A free cooling cooling water circuit and the free cooling cooling circuit, and the free cooling cooling water circuit and the free cooling circuit. A switching mechanism for connecting the cooling circuit of the ring in series, characterized by comprising a control device for performing switching control of the switching mechanism.

  The invention according to claim 4 is the cooling medium cooling refrigeration facility according to claim 3, wherein the switching mechanism is connected between connecting portions of the cooling circuit for free cooling connected to the forward path of the cooling water circulation path for free cooling. A first valve provided, a second valve provided in the intake path of the cooling circuit for free cooling, and a third valve provided in a feed path of the cooling circuit for free cooling, The control device closes the first valve, the second valve, and the third valve when the outdoor wet bulb temperature measured by the outdoor wet bulb thermometer is equal to or higher than a first set value, or free. Stop the pump provided in the cooling water circulation path for cooling and the pump provided in the cooling circuit for free cooling, and the outdoor wet bulb temperature measured by the outdoor wet bulb thermometer is lower than the first set value and the second When the set value is exceeded, the first valve is closed, the second valve and the third valve are opened, the cooling tower and pump of the cooling water circulation path for free cooling, and the cooling circuit for free cooling A cooling tower and a pump are connected in series, and each device is operated to cool the cooling water in the cooling water circulation path for free cooling in two stages, and cooling water is supplied to the free cooling heat exchanger. When the outside air wet bulb temperature measured by the outside air wet bulb thermometer is lower than the second set value, the cooling tower and the pump of the cooling circuit for free cooling are stopped, The valve is opened, the second valve and the third valve are closed, and control is performed to convey the cooling water through the cooling water circulation path for free cooling.

The invention according to claim 5 is the cooling medium cooling refrigeration facility according to claim 2 or claim 4, wherein the heat exchanger for free cooling is provided to a heat load side such as a production apparatus for the cooling water circulation path for free cooling. Cooling for free cooling when Ts is the temperature of the cooling water that is supplied via / or directly, and Tr is the return temperature of the cooling water that is directly returned from the heat load side through the heat exchanger for free cooling. Tower cooling water inlet water temperature (which is equal to the _Tr temperature) ° C is T _w1 , the cooling tower cooling water outlet water temperature ° C for the free cooling is T _w2 , and the cooling tower cooling water outlet water temperature ° C for the free cooling cooling circuit saturated air in the T _w3, T _w1 enthalpy kJ / kgDA of saturated air at ° C. the enthalpy kJ / kgDA saturated air at _{h w1, T w2 ℃ h w2} , T w3 ℃ Enthalpy of air kJ / kgDA is h _w3 , proportional constant C ₁ inherent to the cooling tower of the cooling water circulation path for free cooling, packing tower height Z ₁ of the cooling water circulation path for free cooling, for the free cooling The cooling tower water / air ratio L / G of the cooling water circulation path of N ₁ is N ₁ , the proportional constant C ₂ inherent to the cooling tower of the cooling circuit for free cooling, and the cooling tower packing height Z ₂ of the cooling circuit for free cooling The logarithmic average of the cooling tower characteristics of the cooling water circuit for free cooling shown below is obtained to obtain tower characteristics that can be approximated by defining the cooling tower water / air ratio L / G of the cooling circuit for free cooling as N _2. the logarithmic average method type cooling tower characteristics of statistically reliable and cooling circuits for free cooling, and T _w2 calculated for each air wet-bulb temperature flowing through the cooling tower, calculated for each air wet-bulb temperature flowing through the cooling tower T seeking _w3 ,
Logarithmic average formula of cooling tower characteristics of cooling water circuit for free cooling

Here, Δh ₁ and Δh ₂ are as follows.
Δh ₁ = h _W2 −h ₁
Δh ₂ = h _W1 −h ₂
(U / N) ₁ = C ₁ Z ₁ N ₁ α ⁻¹ , 0.3 ≦ α ≦ 0.5
Logarithmic average formula of cooling tower characteristics of cooling circuit for free cooling

Here, Δh ₁ and Δh ₂ are as follows.
Δh ₁ = h _W3 −h ₁
Δh ₂ = h _W2 −h ₃
(U / N) ₂ = C ₂ Z ₂ N ₂ α ⁻¹ , 0.3 ≦ α ≦ 0.5
The vertical axis represents the cooling tower cooling water inlet / outlet water temperature ° C, and the horizontal axis represents the air wet bulb temperature introduced into the cooling tower ° C. It was calculated for each air wet bulb temperature introduced into the cooling tower. Two cooling tower outlet water temperature lines are created by plotting T _w2 and T _w3 calculated for each temperature of the air wet bulb introduced into the cooling tower, and connecting the plot points to cool the cooling circuit for the free cooling. set the cooling tower cooling water outlet temperature ℃ of ordinate air wet-bulb temperature ℃ the intersection of the horizontal axis parallel to drawn the T _s isothermal line of the outside air wet-bulb temperature first of the the tower outlet water temperature line graph the value, moisture intersection of air and T _s temperature line cooling towers cooling water outlet temperature ℃ vertical axis drawn parallel to the horizontal axis of the graph and the cooling tower outlet water temperature line of the cooling water circulation passage for the free cooling The bulb temperature ° C is set as a second set value of the outside wet bulb temperature.

The invention according to claim 6 is the cooling medium cooling refrigeration facility according to claim 2 or claim 4, wherein the control device is used for the free cooling to a heat load side such as a production device of the cooling water circulation passage for the free cooling. When the cooling water return temperature to be directly supplied via the heat exchanger is Ts, and the cooling water return temperature to be directly returned from the heat load side through the free cooling heat exchanger is Tr, Cooling tower cooling water inlet water temperature for free cooling (this is equal to the _Tr temperature) ° C is T _w1 , cooling tower cooling water outlet water temperature ° C for free cooling is T _w2 , and cooling tower of the cooling circuit for free cooling Cooling water outlet water temperature ° C is T _w3 , saturated air enthalpy kJ / kgDA at T _w1 ° C is h _w1 , saturated air enthalpy kJ / kgDA at T _w2 ° C is h _w2 , T _w3 Enthalpy kJ / kgDA of saturated air at ° C. h _w3 , proportional constant C ₁ inherent to the cooling tower of the cooling water circuit for free cooling, cooling tower packing height Z ₁ of the cooling water circuit for free cooling, The cooling tower water / air ratio L / G of the cooling water circuit for free cooling is N ₁ , the proportional constant C ₂ inherent to the cooling tower of the cooling circuit for free cooling, the cooling tower packing height of the cooling circuit for free cooling Z ₂ , the tower characteristics that can be expressed by approximating the cooling tower water / air ratio L / G of the cooling circuit for free cooling as N _2, and the cooling tower characteristics of the cooling water circuit for free cooling shown below the Chebyshev Chebyshev cooling tower characteristics of formal and cooling circuits for the free cooling formula, and T _w2 calculated for each air wet-bulb temperature flowing through the cooling tower, air flowing through the cooling tower Seek and T _w3 calculated for each wet-bulb temperature,
Chebyshev's formula for cooling tower characteristics of cooling water circuit for free cooling U / N = (Cρ × Δt _w / 4) × {(1 / Δh ₁ ) + (1 / Δh ₂ ) + (1 / Δh ₃ )
+ (1 / Δh ₄ )}
Here, Δh _{1 to} Δh ₄ are as follows.

Δh ₁ = t _W2 + 0.1Δt _W in (h _W -h) value Δh ₂ = t _W2 + 0.4Δt _W in (h _W -h) value Δh ₃ = t _W2 -0.4Δt _W in (h _W the value of the values Δh ₄ = t _W2 -0.1Δt _W of _{-h) (h W -h) (} U / N) 1 = C 1 Z 1 N 1 α -1, 0.3 ≦ α ≦ 0.5
Chebyshev's formula for cooling tower characteristics of a cooling circuit for free cooling U / N = (Cρ × Δt _w / 4) × {(1 / Δh ₁ ) + (1 / Δh ₂ ) + (1 / Δh ₃ )
+ (1 / Δh ₄ )}
Here, Δh _{1 to} Δh ₄ are as follows.

Δh ₁ = t _W3 + 0.1Δt _W in (h _W -h) value Δh ₂ = t _W2 + 0.4Δt _W in (h _W -h) value Δh ₃ = t _W2 -0.4Δt _W in (h _W the value of the values Δh ₄ = t _W2 -0.1Δt _W of _{-h) (h W -h) (} U / N) 2 = C 2 Z 2 N 2 α -1, 0.3 ≦ α ≦ 0.5
The vertical axis represents the cooling tower cooling water inlet / outlet water temperature ° C, and the horizontal axis represents the air wet bulb temperature introduced into the cooling tower ° C. It was calculated for each air wet bulb temperature introduced into the cooling tower. Two cooling tower outlet water temperature lines are created by plotting T _w2 and T _w3 calculated for each temperature of the air wet bulb introduced into the cooling tower, and connecting the plot points to cool the cooling circuit for the free cooling. set the cooling tower cooling water outlet temperature ℃ of ordinate air wet-bulb temperature ℃ the intersection of the horizontal axis parallel to drawn the T _s isothermal line of the outside air wet-bulb temperature first of the the tower outlet water temperature line graph the value, moisture intersection of air and T _s temperature line cooling towers cooling water outlet temperature ℃ vertical axis drawn parallel to the horizontal axis of the graph and the cooling tower outlet water temperature line of the cooling water circulation passage for the free cooling The bulb temperature ° C is set as a second set value of the outside wet bulb temperature.

The invention according to claim 7 is the cooling circuit for free cooling, wherein C ₂ = C ₁ , Z ₂ = Z ₁ , and N ₂ = N ₁ in the cooling medium cooling refrigeration equipment according to claim 5 or claim 6. A cooling tower is provided.
The invention according to claim 8 comprises the cooling tower of the cooling circuit for free cooling, wherein Z ₂ > Z ₁ and N ₂ <N ₁ in the cooling medium cooling refrigeration facility according to claim 5 or claim 6. It is characterized by that.

  The invention according to claim 9 is the cooling medium cooling refrigeration facility according to any one of claims 1 to 8, wherein the cooling water circulation path for free cooling includes the pump and the first valve on a forward path side. A first flow meter that is provided between the pump and a connection portion on the intake path side of the cooling circuit for free cooling, and controls the number of revolutions of the pump in the cooling water circulation path for free cooling; Provided between the connection part on the feed path side of the cooling circuit for free cooling and the return pipe end to the heat exchanger or heat storage tank for free cooling, and the number of rotations of the pump of the cooling circuit for free cooling is And a second flow meter to be controlled.

According to the present invention, for example, when cooling water that has risen to 23 ° C. by free cooling is cooled to 18 ° C., the time during which free cooling is possible has been extended from 2300 hours to 4400 hours in the climate of Tokyo. Indeed, more than half of the year was available. And the energy saving progressed by extending free cooling time.
In the heat exchange of air and water in the cooling tower, the heat exchanged between the air and water in the cooling tower is proportional to the difference Δh between the enthalpy h of air in the tower and the enthalpy h _w of saturated air at the same temperature as the inlet water temperature. Therefore, even if the height of the cooling tower is increased by using only one cooling tower or the cross-sectional area of the tower perpendicular to the air flow direction is increased, the enthalpy of the air introduced into the portion where the capacity is increased is increased. However, it is difficult to cool the water. By connecting two cooling towers in series, the enthalpy of the inlet air to the part where the capacity is increased as the second is the same as the enthalpy of the first inlet air. Since it is very low, heat exchange in the tower section with increased capacity can be promoted to the maximum.

  In particular, by using a freezing cooling tower or backup cooling tower that is idle in winter to increase the cooling tower capacity of free cooling, the free cooling capacity increased without incurring initial costs.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
As shown in FIG. 1, the cooling medium cooling refrigeration facility 1 according to the present embodiment includes a cooling tower CT2 for free cooling and a pump P2 in the forward path 21a of the cooling water circulation path 21 for free cooling. The cooling circuit 22 is connected, and a switching mechanism 30 for connecting the free cooling cooling tower CT3 and the free cooling cooling tower CT2 in series is provided, which is different from the conventional cooling medium cooling refrigeration equipment. . Therefore, in this embodiment, the same code | symbol is attached | subjected to the same structure as the conventional air conditioning apparatus, and the description is abbreviate | omitted.

  In the present embodiment, the cooling water circulation path 21 for free cooling includes the pump P3 and the first valve V1 on the outgoing path 21a side, and the intake path 22a of the cooling circuit 22 for the pump P3 and free cooling. A first flow meter F1 that is provided between the free-cooling cooling water circulation path 21 and controls the rotational speed of the pump P3 of the free-cooling cooling water circulation path 21; A second flow meter F2 is further provided between the connecting portion 24 and the free cooling heat exchanger 16, and controls the number of revolutions of the pump P2 of the free cooling cooling circuit 22.

The cooling circuit 22 for free cooling includes a second valve V2 provided in the intake path 22a and a third valve V3 provided in the feed path 22b.
The first valve V1, the second valve V2, and the third valve V3 constitute a switching mechanism 30 that connects the cooling water circulation path 21 for free cooling and the cooling circuit 22 for free cooling in series. ing. The switching mechanism 30 is controlled by a cooling tower controller (control device) 20.

  The cooling tower controller (control device) 20 is input with the outside air wet bulb temperature T1 measured by the outside air wet bulb thermometer, the intermediate temperature T2 of the heat storage water tank 10, and the cooling water temperature T4 of the free cooling cooling tower CT3. The cooling tower controller (control device) 20 controls the flow rate based on the measured values of the flow meters F1 and F2 by the rotation speed variable mechanism of the pumps P2 and P3, and controls the start and stop of the pumps P2 and P3. The valve V1, the second valve V2, and the third valve V3 are opened and closed, and the fans of the cooling towers CT2 and CT3 are rotated.

  The cooling tower controller (control device) 20 closes the first valve V1, the second valve V2, and the third valve V3 when the outdoor wet bulb temperature T1 becomes equal to or higher than a first set value (for example, 13 ° C.). When the outdoor wet bulb temperature T1 is lower than the first set value and becomes equal to or higher than the second set value (for example, 5 ° C.), the first valve V1 is closed and the second valve V2 and the third valve V3 are turned on. The cooling tower CT3 of the cooling water circulation path 21 for free cooling and the cooling tower CT2 of the cooling circuit 22 for free cooling are connected in series to cool the cooling water of the cooling water circulation path 21 for free cooling in two stages. Along with the control, the cooling water is transferred to the free cooling heat exchanger 16 and when the outside wet bulb temperature becomes lower than the second set value, the cooling tower CT2 of the free cooling cooling circuit 22 and The pump P2 is stopped, the first valve V1 is opened, the second valve V2 and the third valve V3 are closed, and the pump P3 is connected to the free cooling heat exchanger 16 through the free cooling cooling water circulation path 21. The cooling water is controlled by the above. When the outdoor wet bulb temperature T1 is equal to or higher than the first set value, instead of closing the first valve V1, the second valve V2, and the third valve V3, the cooling tower CT2 of the cooling circuit 22 for free cooling, You may stop CT3 and the pumps P2 and P3 of the cooling water circulation path 21 for free cooling.

Next, operation | movement of the cooling-medium cooling refrigeration equipment 1 which concerns on this embodiment is demonstrated based on FIG.
First, the first valve V1, the second valve V2, and the third valve V3 are closed, the refrigerator group 14, the fans of the cooling tower CT1, the pumps P1, CT1, and CT2 are operated, and the water supply temperature T3 of the heat storage water tank 10 is operated. The temperature controller TIC1 starts control so that becomes the set temperature 20 ° C. (steps S1 and S2). Data from the water supply thermometer T3 of the heat storage water tank 10 is input to the temperature controller TIC1. The temperature controller TIC1 controls the start / stop or capacity control of the compressors of the refrigerator group 14, the pumps P1, CP1, CP2, and the cooling tower CT1, and the opening / closing of the three-way valve 19.

Next, the temperature controller TIC1 starts the operation of the pump P5 (step S3).
Next, the cooling tower controller 20 inputs the outside air wet bulb temperature T1 measured by the outside air wet bulb thermometer, and determines whether it is less than 13 ° C. (step S4). If the outdoor wet bulb temperature T1 is 13 ° C. or higher, the process proceeds to step S24, and if the outdoor wet bulb temperature T1 is less than 13 ° C., the process proceeds to step S5.

Next, the cooling tower controller 20 inputs the outdoor wet bulb temperature T1 measured by the outdoor wet bulb thermometer, and determines whether or not the outdoor wet bulb temperature T1 is 5 ° C. or less (step S5). If the outdoor wet bulb temperature T1 is 5 ° C. or higher, the process proceeds to step S17. If the outdoor wet bulb temperature T1 is less than 5 ° C., the process proceeds to step S6.
Next, when the outdoor wet bulb temperature T1 is less than 5 ° C., the cooling tower controller (control device) 20 opens the first valve V1 and closes the second valve V2 and the third valve V3 (step). S6).

Next, the cooling tower controller (control device) 20 operates the fan of the cooling tower CT3 for free cooling, and operates the pumps P3 and P4. The rotational speed of the pump P3 is controlled so that the flow rate measured by the first flow meter F1 becomes the set flow rate of the pump P3 (for example, 80% of the rated flow rate of the pump P3) (steps S7 to S8).
Next, the cooling tower controller (control device) 20 determines whether or not the cooling water temperature T4 of the cooling tower CT3 for free cooling is less than 5 ° C. (step S9). If the cooling water temperature T4 is less than 5 ° C., the fan of the cooling tower CT3 for free cooling is stopped (step S10). If the cooling water temperature T4 is 5 ° C. or higher, the process returns to step S5.

Next, the cooling tower controller (control device) 20 determines whether or not the intermediate water temperature T2 of the heat storage water tank 10 is 18 ° C. or less (step S11). If the intermediate water temperature T2 exceeds 18 ° C., the process returns to step S9. If the intermediate water temperature T2 is 18 ° C. or lower, the pump P4 is stopped (step S12).
Next, the cooling tower controller (control device) 20 determines whether or not the cooling water temperature T4 of the cooling tower CT3 for free cooling is 5 ° C. or higher (step S13). When the cooling water temperature T4 is less than 5 ° C., the process returns to step S9. When the cooling water temperature T4 is 5 ° C. or higher, it is determined whether or not the outdoor wet bulb temperature T1 is 5 ° C. or higher. This selects the operation again based on the outside wet bulb temperature that has not been referenced for a long time. If the outdoor wet bulb temperature T1 is 5 ° C. or higher, the process proceeds to step S15, and if the outdoor wet bulb temperature T1 is less than 5 ° C., the process proceeds to step S6. In step S15, the fan of the cooling tower CT3 of the cooling water circulation path for free cooling is stopped, and the pumps P3 and P4 are stopped (step S15).

Next, the cooling tower controller (control device) 20 determines whether or not to stop the pump P5 (step S16). If the pump P5 is not stopped, the process returns to step S5. When the pump P5 is stopped, the process proceeds to step S26.
On the other hand, when the outdoor wet bulb temperature T1 is 13 ° C. or higher in step S4, the cooling tower controller (control device) 20 closes the first valve V1, the second valve V2, and the third valve V3 ( Step S24).

Next, the cooling tower controller (control device) 20 determines whether or not to stop the pump P5 (step S25). If the pump P5 is not stopped, the process returns to step S4. When stopping the pump P5, the process proceeds to step S26, and the pump P5 is stopped.
Next, the cooling tower controller (control device) 20 stops the refrigerator group 14, the fans of the cooling tower CT1, and the pumps P1, P2, and P3 (step S27).

If the outside wet bulb temperature T1 is 5 ° C. or higher in step S5, the process proceeds to step S17, where the cooling tower controller (control device) 20 is closed with the first valve V1, and the second valve V2 and the second valve V2. Open the third valve V3.
Next, the cooling tower controller (control device) 20 operates the fans of the cooling towers CT2 and CT3 and operates the pumps P2, P3 and P4 (step S18).

Next, the cooling tower controller (control device) 20 controls the rotation speed of the circulation pump P3 so that the flow rate measured by the first flow meter F1 is 80% of the rated flow rate of the pump P2, and the second The rotational speed of the pump P2 is controlled so that the flow rate measured by the flow meter F2 is 80% of the rated flow rate of the pump P2 (steps S19 and S20).
Next, the cooling tower controller (control device) 20 determines whether or not the outside air wet bulb temperature T1 is 13 ° C. or higher (step S21). If the outdoor wet bulb temperature T1 is less than 13 ° C., the process returns to step S5. When the outdoor wet bulb temperature T1 is 13 ° C. or higher, the process proceeds to step S22.

Next, the cooling tower controller (control device) 20 stops the fan of the cooling tower CT2 for free cooling, the fan of the cooling tower CT3, and the pumps P2, P3, and P4 (step S22).
Next, the cooling tower controller (control device) 20 determines whether or not to stop the pump P5 (step S23). When the pump P5 is stopped, the process proceeds to step S26. If the pump P5 is not stopped, the process goes to step S24 to close the first valve V1, the second valve V2, and the third valve V3. Thereafter, the cooling tower controller (control device) 20 determines whether or not to stop the pump 5 again (step S25). When not stopping pump P5, it returns to Step S4, and when stopping pump P5, it progresses to Step S26 and continues to Step S27.

The operation of the cooling medium cooling refrigeration facility 1 according to the present embodiment is controlled as described above.
Next, operations in the summer, winter and intermediate periods will be described with reference to FIGS.
First, the operation in summer will be described. Here, in the summer, the outdoor wet bulb temperature was set to 13 ° C. or higher, that is, the first set value of the outdoor wet bulb temperature of the cooling tower controller 20 (4360 hours per year in Tokyo weather data).

  In this season, the cooling in the cooling tower CT1 becomes the outdoor wet bulb temperature T1 that cannot be cooled below the set water temperature of 18 ° C., so that the first valve V1 and the second valve V2 as shown in step S24 of FIG. The third valve V3 is closed. The cooling tower CT3 fan for free cooling and the pump P3 for the cooling tower CT3 are not operated. The fan of the cooling tower CT2 and the pump P2 are not operated. The pump P4 that sends the water in the heat storage water tank 10 to the heat exchanger 16 for free cooling is also stopped. The means for cooling the cold water on the production device group 13 side operates the refrigerator group 14, the cooling tower CT 1, the pumps CP 1 and P 1, and the water in the heat storage tank 10 is cooled by the 7 ° C. cold water cooled by the refrigerator group 14. Cool to 20 ° C. with heat exchanger 15. The water cooled to 20 ° C. is sent to the production device group 13 by the pump P5 in the heat storage water tank 10, and the water heated in the production device group 13 is returned to the heat storage water tank 10 and again in the heat exchanger 15. To be cooled. When the water supply temperature T3 in the heat storage water tank 10 becomes the set temperature 20 ° C. or less, the cold water between the refrigerator group 14 and the heat exchanger 15 starts the bypass operation by the three-way valve 19, and when it still falls below the set water temperature, the refrigerator group 14 To stop.

Next, the operation in winter will be described. Here, the outdoor wet bulb temperature was less than 5 ° C. in winter (2300 hours per year in Tokyo weather data).
In this season, since it becomes the second set temperature (5 ° C.) of the outdoor wet bulb temperature T1 at a cooling water temperature of 18 ° C. or lower, the first valve V1 is opened as shown in step S6 of FIG. The second valve V2 and the third valve V3 are closed, and the fan of the cooling tower CT3 for free cooling and the pumps P3 and P4 are operated as shown in step S7. The cold water in the heat storage water tank 10 is cooled to 20 ° C. by the heat exchanger 16 for free cooling by the 18 ° C. cooling water cooled by the cooling tower CT3 for free cooling. The cold water cooled to 20 ° C. is conveyed to the production apparatus group 13 by the pump P5 in the heat storage water tank 10. The cold water heated by the production apparatus group 13 returns to the heat storage water tank 10 and is cooled again by the heat exchanger 16 for free cooling.

Next, the operation in the intermediate period will be described. In the intermediate period, the outside air wet bulb temperature was set to 5 ° C. or more and less than 13 ° C.
In this season, the operation of one cooling tower CT3 for free cooling does not lower the cooling water temperature to 18 ° C. or lower, and the first outside air wet bulb temperature T1 at the cooling tower outlet water temperature of 18 ° C. or lower in two-stage series operation. Therefore, the first valve V1 is closed, the second valve V2 and the third valve V3 are opened, and the cooling towers CT2 and CT3 for free cooling and the pumps P2, P3 and P4 are opened. The water in the heat storage water tank 10 is cooled to 20 ° C. by the free cooling heat exchanger 16 by the 18 ° C. cooling water cooled by the free cooling cooling towers CT 2 and CT 3. The water cooled to 20 ° C. is sent to the production device group 13 by the pump P5 in the heat storage water tank 10, and the water heated by the production device group 13 is returned to the heat storage water tank 10, and again a heat exchanger for free cooling. 16 is cooled. The opposing cooling water at 18 ° C. in the heat exchanger 16 is conveyed to the free cooling cooling tower CT3 by the pump P3. In the first cooling cooling tower CT3, the outdoor wet bulb temperature T1 at that time The cooling water is cooled to a temperature close to the set water temperature of 18 ° C., depending on the capacity of the cooling tower CT3 for free cooling. This cooling water is transported to the second-stage free cooling cooling tower CT2, and the second-stage free cooling cooling tower CT2 cools the cooling water cooled in the first stage to a set water temperature of 18 ° C. or lower. It is again conveyed to the heat exchanger 16 for free cooling. Here, although not shown in FIG. 1, the cooling tower CT2 may be connected to the condenser side of the refrigerator group 14 via another switching device, and is disconnected from the refrigerator group 14 and in an idle state at a low load. It is desirable that the cooling tower is used, and if this is used, the energy can be saved significantly without increasing the initial cost.

As described above, according to the present embodiment, the cooling tower CT2 and the cooling tower CT3 for free cooling that are idle due to the low heat load in the winter or intermediate period are arranged in series, so that the cooling water for free cooling can be obtained. Since it can cool in two steps, the cold water temperature can be lowered than before.
According to the cooling medium cooling refrigeration facility 1 according to the present embodiment, for example, a cooling tower that is idle due to a low heat load in winter or an intermediate period, or a cooling tower for backup and a cooling tower for free cooling are arranged in series. Can cool the water at 23 ° C to 20 ° C on the first unit and cool the water at 20 ° C to 18 ° C on the second unit. A long-time free cooling system can be obtained.

  The present invention is not limited to this embodiment, and if the switching device to which the cooling circuit for free cooling can be connected in series is provided in the outgoing path of the cooling water circulation path for free cooling, the object is satisfied. Instead of indirectly connecting low-temperature cold water produced by the refrigerator group or cooling water cooled by the cooling tower via the heat exchanger 15 or the heat exchanger 16 to the heat storage water tank of the embodiment shown in FIG. You may introduce | transduce into the water tank directly the cooling water cooled with the cooling water of this, or a cooling tower.

Next, an overview of serial cooling of two cooling towers will be described.
The amount of heat exchanged between the cooling tower air and water is proportional to the difference Δh between the enthalpy h of the air and the enthalpy hw of the saturated air at the same temperature as the inlet water temperature, and the cooling is below the enthalpy h of the air and the wet bulb temperature t ′. Is impossible. In other words, if the water is not heated, it can be cooled to near the wet bulb temperature. The state of water and air when two cooling towers are cooled in series is shown in FIG. Here, if the water at the water temperature of one cooling tower is cooled, the cooling heat amount of the cooling tower is equal to the heat balance of the amount of heat the water receives from the coil of the air conditioner or device, and the cooled water is wet. The ball temperature is not reached and the water temperature t _W1 and the wet bulb temperature t ₁ ′ are in the middle. In addition, the air at this time exchanges heat, so that the closer to the outlet, the enthalpy increases and the wet bulb temperature rises. Even if the height of the cooling tower is increased and the number of exchangers is increased, there is no effect. Therefore, when the water cooled in the first unit is further cooled in another cooling tower, it becomes possible to exchange heat with air having a low wet bulb temperature by taking in fresh air (outside air), and the water temperature t _W2 cooled in the previous stage The following state can be obtained.

Next, calculation in series with two cooling towers will be described.
Various symbols used for calculation are determined as follows.
t _w1 = first cooling tower cooling water inlet water temperature [° C]
t _w2 = cooling water outlet water temperature of the first cooling tower [° C]
t _w3 = cooling water outlet water temperature of the second cooling tower [° C]
h _w1 = Saturated air enthalpy of the first cooling tower cooling water inlet water temperature [kJ / kgDA]
h _w2 = Saturated air enthalpy of the first cooling tower cooling water outlet water temperature [kJ / kgDA]
h _w3 = Saturated air enthalpy of the second cooling tower cooling water outlet water temperature [kJ / kgDA]
h ₁ = 1st and 2nd cooling tower inlet air enthalpy [kJ / kgDA]
h ₂ = the first cooling tower outlet air enthalpy [kJ / kgDA]
h ₃ = 2nd cooling tower outlet air enthalpy [kJ / kgDA]
Cρ = specific gravity of water [kJ / kg]
Ka = enthalpy standard overall area heat transfer coefficient [kJ / m ² · ΔI · h]
C = Proportional constant specific to cooling tower L = Circulating water volume [kg / h]
G = cooling tower airflow [kg / h]
A = Tower cross section perpendicular to the direction of air flow [m ² ]
Z = height of packing [m]
α, β = constant determined by packing N = water / air ratio L / G
X = approximately calculated tower characteristic U / N
Y ₁ = tower characteristic U / N calculated by logarithmic average method
Y ₂ = Tower characteristic U / N calculated by Chebyshoff formula
The cooling of water by the cooling tower is different from the cooling of a general heat exchanger, and heat exchange is performed by direct contact between water and air. Therefore, not only sensible heat transfer but also water vapor transfer occurs, resulting in complicated analysis. However, since the evaporation amount of the cold water with respect to the cooling tower is as small as less than 1%, the transferred water vapor flow rate is negligible. Therefore, the amount of heat given to the atmosphere by the cooling water of the cooling tower and the amount of heat Q of the heat balance where the cooling water is cooled are given by the following equations.

dQ = G × (dh) = (− Cρ) × L × (dT _w ) (1)
FIG. 4 shows the specific enthalpy relationship between the inlet water temperature t _w1 , the outlet water temperature t _w2 , the inlet air wet bulb temperature t ₁ ′, and the outlet air wet bulb temperature t ₂ ′ in the counterflow type cooling tower. Indicates the state of heat exchange. The inlet air changes with a gradient line (operation line) which is L / G. Also, when considering the heat exchanger for small height dZ of counterflow cooling towers, small amount of heat exchange Q in the minute height, and the water temperature t saturated air ratio enthalpy of _w equal temperature h _w in that part It is proportional to the difference (h _w −h) from the specific enthalpy h of air and is given by the following equation.

dQ = Ka × (h _w −h) × dZ × A (2)
Equation (3) is obtained from equations (1) and (2).
dQ = G × (dh) = (− Cρ) × L × (dT _w ) = Ka × (h _w −h) × dZ × A (3)
Equation (3) is modified to obtain equations (4) and (5).

Ka × dZ × A / G = (dh) / (h _w −h) (4)
Ka × dZ × A / L = (− Cρ) × (dT _w ) / (h _w −h) (5)
When the equations (4) and (5) are integrated with respect to the packing height Z, the equations (6) and (7) are obtained.

Equations (6) and (7) are basic equations of the counter-flow cooling tower, U is the number of moving units, and N ₀ is a numerical value replaced with the initial value of L / G. U / N is called tower performance factor. The calculation method is approximated by calculating the average value of the variables in the integral symbol of equation (7). Representatively, in the case of the logarithmic average method and Chebyshev's formula (appropriately divided into four, 1 / ( In the case of calculating the average value of h _w −h), U and U / N can be obtained.

  The case of the logarithmic average method is shown in equation (8).

Here, Δh ₁ and Δh ₂ are as follows.
Δh ₁ = h _W2 −h ₁
Δh ₂ = h _W1 −h ₂
In the case of using Chebyshev's formula, the calculation result is shown in the equation (9) as in the case of the logarithmic average method.

U / N = (Cρ × Δt _w / 4) × {(1 / Δh ₁ ) + (1 / Δh ₂ ) + (1 / Δh ₃ )
+ (1 / Δh ₄ )} (9)
Here, Δh _{1 to} Δh ₄ are as follows.
Δh ₁ = t _W2 + 0.1Δt _W in (h _W -h) value Δh ₂ = t _W2 + 0.4Δt _W in (h _W -h) value Δh ₃ = t _W2 -0.4Δt _W in (h _W -H) value Δh ₄ = t _W2 -0.1 Δt _W value (h _W -h) The thermal characteristic Ka is a numerical value representing the performance of the packing material, and the theory is that the flow of water and air in the tower is complicated. It is difficult to ask for. Therefore, Ka is obtained in advance by an empirical formula for each packing, and the empirical formula is obtained by formula (10) as a function of (L / A) and (G / A).

Ka = C (L / A) α (G / A) β ... (10)
Here, α + β≈1.
Substituting equation (10) into U / N in equation (7) yields equation (11).
U / N = Ka × A × Z / L = CZ [L / A] α ⁻¹ [G / A] ^{− (} α ⁻¹⁾ = CZNα ⁻¹
(11)
Here, when CZ is set as a constant K, equation (12) is obtained.

U / N = KNα ⁻¹ (12)
If the cooling tower manufacturer's rated capacity value is known, U / N is obtained and N and K are obtained. α takes around 0.4, and U / N in the equation (12) is obtained.
(For example, N = L / G is obtained from the cooling tower of rated water volume L, rated air volume G, rated outdoor wet bulb temperature t ₁ ′, rated inlet water temperature t _W1 , outlet water temperature t _W2 , and rated water temperatures t _W1 , t with the h ₁ and calculated values h ₂ from the rated rated outside air wet-bulb temperature of _W2 (8) and calculated back expression leads to K = cooling tower seeking U / N.)
Here, the value obtained by changing the tower characteristic U / N obtained by the equation (12) and the inlet water temperature _tw1 by 0.1 ° C. is substituted into _tw2 of the equation (8) or (9), and the U / N can be obtained as a calculation result points t _w2 such are equal.

The _tw2 obtained from the above is the water temperature at the outlet of the first cooling tower.
Next, the outlet water temperature t _W3 of the second cooling tower is obtained. The state of water and air in series of two cooling towers is shown in FIG. Here, since the outlet water temperature t _W2 of the first cooling tower becomes the inlet water temperature of the second cooling tower, each temperature state of the formula (8) or the formula (9) is replaced as follows.
t _W1 → t _W2
t _W2 → t _W3
h _W1 → h _W2
h _W2 → h _W3
h ₂ → h ₃
Therefore, the approximate expression of U / N is the expression (13) in the case of the logarithmic average method, and the expression (14) in the case of the Chebyshev formula.

Here, Δh ₁ and Δh ₂ are as follows.
Δh ₁ = h _W3 −h ₁
Δh ₂ = h _W2 −h ₃
In the case of using Chebyshev's formula, the calculation result is described in the equation (14) as in the case of the logarithmic average method.

U / N = (Cρ × Δt _w / 4) × {(1 / Δh ₁ ) + (1 / Δh ₂ ) + (1 / Δh ₃ )
+ (1 / Δh ₄ )} (14)
Here, Δh _{1 to} Δh ₄ are as follows.
Δh ₁ = t _W3 + 0.1Δt _W in (h _W -h) value Δh ₂ = t _W2 + 0.4Δt _W in (h _W -h) value Δh ₃ = t _W2 -0.4Δt _W in (h _W -H) value Δh ₄ = t _W2 -0.1 Δt _W (h _W -h) value Further, the tower characteristic U / N according to the equation (12) of the second cooling tower is obtained. N and K values vary depending on the capacity of the second cooling tower. If the capacity is the same as that of the first cooling tower, the N and K values will be the same, so that the tower characteristic U / N and the inlet water temperature _tw2 determined by the equation (12) are 0.1 as in the first cooling tower. A value changed by ° C. was substituted for _tw3 in the equation (13) or (14), and a point _{tw3 at} which U / N becomes equal was attached as a calculation result.

The _tw3 obtained from the above is taken as the second cooling tower outlet water temperature.
FIG. 5 shows the relationship between the outside air wet bulb temperature and the outlet water temperature when the inlet water temperature of the first cooling tower in series of two cooling towers of the same capacity is 23 ° C. The outside air wet bulb temperature at which the cooling water outlet water temperature of 18 ° C. can be taken out is 5 ° C. or less in one cooling tower, which is 2300 hours or less per year in Tokyo weather data. However, in the case of two cooling towers in series, the outside wet bulb temperature may be 13 ° C., and the Tokyo meteorological data was 4000 hours per year.

Next, the case where the capacity of the second cooling tower is large will be described. If the same amount of water as the first unit is passed through a cooling tower with a large capacity of the second unit, the amount of water L does not change. However, since the amount of air G is large, N is small and the tower characteristic (12) equation U / N is large. That is, those with a _{Z 2> Z 1, N 2} < is N _1, the cooling tower of the cooling circuit for free cooling. Therefore, the exit temperature _tw3 of the second cooling tower in the approximate expression (13) or (14) can be lowered. Considering this tendency, the N and K values of the second cooling tower are newly obtained, and two units are obtained by the tower characteristics (12) and the approximate expression (13) or (14) in the same manner as described above. The eye cooling tower outlet temperature _tw3 can be calculated.

  FIG. 6 shows the relationship between the external wet-bulb temperature at the cooling tower inlet water temperature of 23 ° C. and the cooling tower outlet temperature when the capacity of the second cooling tower is 1.0 to 2.0 times. If the capacity of the second cooling tower is the same as the capacity of the first cooling tower, an outside air wet bulb temperature of less than 13 ° C is required to bring the cooling tower outlet water temperature to 18 ° C. If the capacity of the second cooling tower is twice the capacity of the first one, it would suffice if the outdoor wet bulb temperature is less than 15 ° C. It was.

  Since the return temperature of the air conditioner varies depending on the indoor temperature condition or the underfloor blowing temperature condition, the precooling water temperature condition and the cooling water temperature condition vary. Next, when the cooling water inlet water temperature is 21 ° C. instead of 23 ° C. and the water must be sent to the heat exchanger at 16 ° C., the relationship between the outside wet bulb temperature and the cooling tower outlet water temperature in FIG. It becomes. If the capacity of the second cooling tower is the same as that of the first cooling tower, the outdoor wet-bulb temperature of less than 11 ° C is required to bring the cooling tower outlet water temperature to 16 ° C. According to the data of 3600 hours a year, if the capacity of the second cooling tower is twice that of the first, the outdoor wet bulb temperature should be less than 13 ° C. It was 4400 hours.

  As a result, the annual free cooling operation time can be extended by connecting two cooling towers in series, and the free cooling operation time can be extended by increasing the cooling tower capacity, thereby reducing annual energy consumption and reducing running costs. These systems are actually determined by balancing the initial cost increase due to the cooling tower capacity increase and the running cost reduction due to the long free cooling.

(Second embodiment)
The present invention satisfies the object if there is a switching device in which a cooling circuit for free cooling can be connected in series in the outgoing path 21a of the cooling water circulation path for free cooling, so the cooling medium cooling refrigeration equipment according to the present embodiment In 1A, an example in which the heat exchanger 16 in the first embodiment is removed and cooling water cooled by free cooling is directly introduced into the heat storage water tank 10 is shown in FIG.

In the cooling medium cooling refrigeration facility 1A according to the present embodiment, the cooling water in the cooling water circulation path, the cooling water in the free cooling cooling water circulation path 21, and the cooling water in the cooling water return pipes 11 and 12 are received or sent out. A heat storage tank 10 is provided.
In addition, the pump P41 which sends the water in the heat storage water tank 10 to the cooling water circulation path 21 for free cooling was an inverter system.

Since the other structure is the same as that of the cooling medium cooling refrigeration facility 1 according to the first embodiment, the description thereof is omitted.
In the cooling medium cooling refrigeration facility 1A according to the present embodiment, the same operational effects as those of the first embodiment can be obtained.
(Third embodiment)
The present invention satisfies the object if there is a switching device in which a cooling circuit for free cooling can be connected in series in the outgoing path 21a of the cooling water circulation path for free cooling, so the cooling medium cooling refrigeration equipment according to the present embodiment In 1B, the regenerative water tank 10 in the first embodiment is replaced with a return header 101 and a forward header 102 in which the high temperature side and the low temperature side are separated and the volume is reduced, and low temperature cold water and cooling towers produced by the refrigerator group 14 are replaced. FIG. 9 shows an example in which the cooling water cooled by CT2 and CT3, and further the cold water flowing through the cold water return pipe 11 and the cold water return pipe 12 sent to a heat load such as the production apparatus group 13 are directly connected.

In the cooling medium cooling refrigeration facility 1A according to the present embodiment, the cooling water in the cooling water circulation path, the cooling water in the free cooling cooling water circulation path 21, and the cooling water in the cooling water return pipes 11 and 12 are received or sent out. A return header 101 and a forward header 102 are provided.
Since the other structure is the same as that of the cooling medium cooling refrigeration facility 1 according to the first embodiment, the description thereof is omitted.

In the cooling medium cooling refrigeration facility 1A according to the present embodiment, the same operational effects as those of the first embodiment can be obtained.
(Fourth embodiment)
In the present embodiment, the cooling water is fed to the heat exchangers 15 and 16 in the third embodiment by returning the header 101 by the conveying force of the pumps P4 and CP2, and the outlet pipe 18 of the cold water returning from the heat exchanger 16 is sent. It is different from the third embodiment in that it is connected to the header 102. An example of this embodiment is shown in FIG.

  Also in the present embodiment, the low-temperature cold water produced by the refrigerator group 14, the cooling water cooled by the cooling towers CT <b> 2 and CT <b> 3, and the cold water forward pipe 11 and the cold water return pipe sent to the heat load of the production apparatus group 13 and the like The cold water flowing through 12 can be directly connected.

It is a lineblock diagram of the cooling-medium cooling refrigeration equipment concerning a first embodiment of the present invention. It is a flowchart explaining the operation | movement of a summer, winter, and a middle period based on the cooling-medium cooling refrigeration equipment which concerns on 1st embodiment of this invention. It is a relationship diagram of the enthalpy h of air at the time of connecting two cooling towers for free cooling in series, and the external air wet bulb temperature t. FIG. 4 is a relationship diagram of air enthalpy h and outside wet bulb temperature t in one cooling tower for free cooling. It is a figure which shows the relationship between the external air wet-bulb temperature at the time of inlet_port | entrance 23 degreeC at the time of connecting two cooling towers of the same capability, and an exit temperature. It is a figure which shows the relationship between the outside wet bulb temperature at the time of inlet_port | entrance temperature 23 degreeC at the time of connecting the cooling tower with the 2nd large capacity | capacitance, and outlet temperature. It is a figure which shows the relationship between the external wet-bulb temperature at the time of inlet_port | entrance 21 degreeC at the time of connecting the cooling tower with the 2nd large capacity | capacitance, and outlet temperature. It is a block diagram of the cooling-medium cooling refrigeration equipment which concerns on 2nd embodiment of this invention. It is a block diagram of the cooling-medium cooling refrigeration equipment which concerns on 3rd embodiment of this invention. It is a block diagram of the cooling-medium cooling refrigeration equipment which concerns on 4th embodiment of this invention. It is a block diagram of the conventional cooling medium cooling refrigeration equipment. It is a flowchart explaining the operation | movement of a summer, winter, and an intermediate period based on the cooling-medium cooling refrigeration equipment of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Thermal storage tank 13 Production apparatus group 14 Refrigerator group 15 Heat exchanger 16 Heat exchanger 20 for free cooling Cooling tower controller (control apparatus)
21 Cooling water circulation path 21a for free cooling Outbound path 22 Cooling circuit 22a for free cooling Intake path 22b Feed path 23, 24 Connection section 30 Switching mechanism 101 Return header 102 Forward header CT1 Cooling tower CT2, CT3 Cooling tower for free cooling P2, P3, P4, P5, CT1, CT2 Pump V1 First valve V2 Second valve V3 Third valve F1 First flow meter F2 Second flow meter T1 Outside air wet bulb temperature T2 Middle heat storage water tank 10 Water temperature T3 Water supply temperature T4 of the heat storage tank 10 Cooling water temperature of the cooling tower CT3 for free cooling

Claims (9)

A heat storage tank for storing cold water;
An outside air wet bulb thermometer,
A cooling water circuit including a refrigerator group, a cooling tower, and a pump;
A cooling water circuit for free cooling with a cooling tower and a pump;
A heat exchanger for exchanging heat between the cooling water in the cooling water circulation path and the water in the heat storage water tank;
A heat exchanger for exchanging heat between the cooling water in the cooling water circulation path for free cooling and the water in the heat storage water tank;
A cooling tower and a pump, a cooling circuit for free cooling connected to an outward path of the cooling water circulation path for free cooling and cooling the cooling water of the cooling water circulation path for free cooling;
A switching mechanism provided between the free cooling cooling water circulation path and the free cooling cooling circuit, and connecting the free cooling cooling water circulation path and the free cooling cooling circuit in series;
And a control device that performs switching control of the switching mechanism. In the cooling medium cooling refrigeration equipment according to claim 1,
The switching mechanism includes a first valve provided between connection parts of the free cooling cooling circuit connected to the free cooling cooling water circulation path, and a free cooling cooling circuit intake path. A second valve provided, and a third valve provided in a feed path of the cooling circuit for free cooling,
The control device closes the first valve, the second valve, and the third valve when the outdoor wet bulb temperature measured by the outdoor wet bulb thermometer is equal to or higher than a first set value, or Stop the pump in the cooling water circuit for free cooling and the pump in the cooling circuit for free cooling,
When the outside air wet bulb temperature measured by the outside air wet bulb thermometer is lower than the first set value and equal to or higher than the second set value, the first valve is closed, and the second valve and the third valve are closed. Open the valve, connect the cooling tower and pump of the cooling water circulation path for free cooling and the cooling tower and pump of the cooling circuit for free cooling in series, operate each device, and cool the cooling for free cooling. Along with the control to cool the cooling water in the water circulation path in two stages, the cooling water is transferred to the free cooling heat exchanger,
When the outside air wet bulb temperature measured by the outside air wet bulb thermometer is lower than the second set value, the cooling tower and the pump of the cooling circuit for free cooling are stopped, the first valve is opened, Cooling medium cooling and refrigeration equipment, wherein the second valve and the third valve are closed and control is performed to convey the cooling water to the free cooling heat exchanger via the free cooling cooling water circulation path . An outside air wet bulb thermometer,
A cooling water circuit including a refrigerator group, a cooling tower, and a pump;
A cooling water circuit for free cooling with a cooling tower and a pump;
A cold water return pipe equipped with a heat load such as a production device and a pump;
A heat storage water tank or a forward header and a return header for receiving or sending the cooling water in the cooling water circulation path, the cooling water in the cooling water circulation path for free cooling, and the cooling water in the cooling water return pipe; and
A cooling tower and a pump, a cooling circuit for free cooling connected to an outward path of the cooling water circulation path for free cooling and cooling the cooling water of the cooling water circulation path for free cooling;
A switching mechanism provided between the free cooling cooling water circulation path and the free cooling cooling circuit, and connecting the free cooling cooling water circulation path and the free cooling cooling circuit in series;
And a control device that performs switching control of the switching mechanism. In the cooling medium cooling refrigeration equipment according to claim 3,
The switching mechanism includes a first valve provided between connection parts of the free cooling cooling circuit connected to the free cooling cooling water circulation path, and a free cooling cooling circuit intake path. A second valve provided, and a third valve provided in a feed path of the cooling circuit for free cooling,
The control device closes the first valve, the second valve, and the third valve when the outdoor wet bulb temperature measured by the outdoor wet bulb thermometer is equal to or higher than a first set value, or Stop the pump in the cooling water circuit for free cooling and the pump in the cooling circuit for free cooling,
When the outside air wet bulb temperature measured by the outside air wet bulb thermometer is lower than the first set value and equal to or higher than the second set value, the first valve is closed, and the second valve and the third valve are closed. Open the valve, connect the cooling tower and pump of the cooling water circulation path for free cooling and the cooling tower and pump of the cooling circuit for free cooling in series, operate each device, and cool the cooling for free cooling. Along with the control to cool the cooling water in the water circulation path in two stages, the cooling water is transferred to the free cooling heat exchanger,
When the outside air wet bulb temperature measured by the outside air wet bulb thermometer is lower than the second set value, the cooling tower and the pump of the cooling circuit for free cooling are stopped, the first valve is opened, A cooling medium cooling refrigeration facility, wherein the second valve and the third valve are closed and control is performed to convey the cooling water through the cooling water circulation path for free cooling. In the cooling medium cooling refrigeration equipment according to claim 2 or 4,
The controller is
The cooling water going-out temperature supplied via the free cooling heat exchanger / directly to the heat load side such as the production system of the cooling water circuit for the free cooling is Ts, and the heat exchange for the free cooling from the heat load side. When the cooling water return temperature that is returned directly or via the vessel is Tr,
The free cooling cooling tower cooling water inlet water temperature (which is equal to the _Tr temperature) ° C. is T _w1 , the free cooling cooling tower cooling water outlet water temperature is T _w2 , and the free cooling cooling circuit cooling is performed. Tower cooling water outlet water temperature ° C is T _w3 , saturated air enthalpy kJ / kgDA at T _w1 ° C is h _w1 , saturated air enthalpy kJ / kgDA at T _w2 ° C is h _w2 , saturated air enthalpy at T _w3 ° C kgDA is h _w3 , the proportional constant C ₁ unique to the cooling tower of the cooling water circulation path for free cooling, the cooling tower packing height Z ₁ of the cooling water circulation path for free cooling, and the cooling water circulation path of the cooling water circulation path for free cooling the cooling tower water air ratio L / G N _1, the free cooling tower specific proportionality constant C ₂ cooling circuit for cooling, the cooling of the cooling circuit for the free cooling Packing height Z _2, the cooling tower water air ratio L / G of the cooling circuit for a free cooling approximated defined as N ₂ seek tower characteristics represented by, the cooling water circulation passage for free cooling shown below Based on the logarithmic average formula of the cooling tower characteristics and the logarithmic average formula of the cooling tower characteristics of the cooling circuit for free cooling, _Tw2 calculated for each air wet bulb temperature flowing through the cooling tower and each air wet bulb temperature flowing through the cooling tower _{Find the} calculated T _w3 ,
Logarithmic average formula of cooling tower characteristics of cooling water circuit for free cooling

Here, Δh ₁ and Δh ₂ are as follows.
Δh ₁ = h _W2 −h ₁
Δh ₂ = h _W1 −h ₂
(U / N) ₁ = C ₁ Z ₁ N ₁ α ⁻¹ , 0.3 ≦ α ≦ 0.5
Logarithmic average formula of cooling tower characteristics of cooling circuit for free cooling

Here, Δh ₁ and Δh ₂ are as follows.
Δh ₁ = h _W3 −h ₁
Δh ₂ = h _W2 −h ₃
(U / N) ₂ = C ₂ Z ₂ N ₂ α ⁻¹ , 0.3 ≦ α ≦ 0.5
The vertical axis represents the cooling tower cooling water inlet / outlet water temperature ° C, and the horizontal axis represents the air wet bulb temperature introduced into the cooling tower ° C. It was calculated for each air wet bulb temperature introduced into the cooling tower. create two cooling tower outlet water temperature lines and T _w3 calculated for each air wet-bulb temperature connecting each plot by plotting points to be introduced T _w2 to the cooling tower,
Air wet-bulb temperature ℃ intersections of the T _s temperature line cooling towers cooling water outlet temperature ℃ vertical axis drawn parallel to the horizontal axis of the graph and the cooling tower outlet water temperature line of the cooling circuit for the free cooling As the first set value of the outside wet bulb temperature,
The intersection of the air wet-bulb temperature ℃ the horizontal axis parallel to drawn the T _s temperature line cooling towers cooling water outlet temperature ℃ the longitudinal axis of the graph and the cooling tower outlet water temperature line of the cooling water circulation passage for the free cooling Is a second set value of the outside air wet bulb temperature. In the cooling medium cooling refrigeration equipment according to claim 2 or 4,
The controller is
The cooling water going-out temperature supplied via the free cooling heat exchanger / directly to the heat load side such as the production system of the cooling water circuit for the free cooling is Ts, and the heat exchange for the free cooling from the heat load side. When the cooling water return temperature that is returned directly or via the vessel is Tr,
The free cooling cooling tower cooling water inlet water temperature (which is equal to the _Tr temperature) ° C. is T _w1 , the free cooling cooling tower cooling water outlet water temperature is T _w2 , and the free cooling cooling circuit cooling is performed. Tower cooling water outlet water temperature ° C is T _w3 , saturated air enthalpy kJ / kgDA at T _w1 ° C is h _w1 , saturated air enthalpy kJ / kgDA at T _w2 ° C is h _w2 , saturated air enthalpy at T _w3 ° C kJ / kgDA is h _w3 , the proportional constant C ₁ unique to the cooling tower of the cooling water circulation path for free cooling, the cooling tower packing height Z ₁ of the cooling water circulation path for free cooling, and the cooling water circulation path of the cooling water circulation path for free cooling the cooling tower water air ratio L / G N _1, the free cooling tower specific proportionality constant C ₂ cooling circuit for cooling, the cooling of the cooling circuit for the free cooling Packing height Z _2, obtains the tower characteristic represented a cooling tower water air ratio L / G of the cooling circuit for the free cooling approximated stipulates that N _2, cooling water circulation circuit cooling for free cooling shown below the Chebyshev official cooling tower characteristics of Chebyshev formulas and cooling circuits for free cooling of the cooling tower properties of water circulation path, and T _w2 calculated for each air wet-bulb temperature flowing through the cooling tower, each air wet-bulb temperature flowing through the cooling tower To calculate T _w3 calculated in
Chebyshev's formula for cooling tower characteristics of cooling water circuit for free cooling U / N = (Cρ × Δt _w / 4) × {(1 / Δh ₁ ) + (1 / Δh ₂ ) + (1 / Δh ₃ )
+ (1 / Δh ₄ )}
Here, Δh _{1 to} Δh ₄ are as follows.
Δh ₁ = t _W2 + 0.1Δt _W in (h _W -h) value Δh ₂ = t _W2 + 0.4Δt _W in (h _W -h) value Δh ₃ = t _W2 -0.4Δt _W in (h _W the value of the values Δh ₄ = t _W2 -0.1Δt _W of _{-h) (h W -h) (} U / N) 1 = C 1 Z 1 N 1 α -1, 0.3 ≦ α ≦ 0.5
Chebyshev's formula for cooling tower characteristics of a cooling circuit for free cooling U / N = (Cρ × Δt _w / 4) × {(1 / Δh ₁ ) + (1 / Δh ₂ ) + (1 / Δh ₃ )
+ (1 / Δh ₄ )}
Here, Δh _{1 to} Δh ₄ are as follows.
Δh ₁ = t _W3 + 0.1Δt _W in (h _W -h) value Δh ₂ = t _W2 + 0.4Δt _W in (h _W -h) value Δh ₃ = t _W2 -0.4Δt _W in (h _W the value of the values Δh ₄ = t _W2 -0.1Δt _W of _{-h) (h W -h) (} U / N) 2 = C 2 Z 2 N 2 α -1, 0.3 ≦ α ≦ 0.5
The vertical axis represents the cooling tower cooling water inlet / outlet water temperature ° C, and the horizontal axis represents the air wet bulb temperature introduced into the cooling tower ° C. It was calculated for each air wet bulb temperature introduced into the cooling tower. create two cooling tower outlet water temperature lines and T _w3 calculated for each air wet-bulb temperature connecting each plot by plotting points to be introduced T _w2 to the cooling tower,
Air wet-bulb temperature ℃ intersections of the T _s temperature line cooling towers cooling water outlet temperature ℃ vertical axis drawn parallel to the horizontal axis of the graph and the cooling tower outlet water temperature line of the cooling circuit for the free cooling As the first set value of the outside wet bulb temperature,
The intersection of the air wet-bulb temperature ℃ the horizontal axis parallel to drawn the T _s temperature line cooling towers cooling water outlet temperature ℃ the longitudinal axis of the graph and the cooling tower outlet water temperature line of the cooling water circulation passage for the free cooling Is a second set value of the outside air wet bulb temperature. In the cooling medium cooling refrigeration equipment according to claim 5 or 6,
A cooling medium cooling refrigeration facility comprising a cooling tower of a cooling circuit for free cooling, wherein C ₂ = C ₁ , Z ₂ = Z ₁ , and N ₂ = N ₁ . In the cooling medium cooling refrigeration equipment according to claim 5 or 6,
A cooling medium cooling refrigeration facility comprising a cooling tower of a cooling circuit for free cooling, wherein Z ₂ > Z ₁ and N ₂ <N ₁ . The cooling medium cooling refrigeration equipment according to any one of claims 1 to 8,
The cooling water circulation path for free cooling includes the pump and the first valve on the outgoing path side, and is provided between the pump and a connection part on the intake path side of the cooling circuit for free cooling, A first flow meter for controlling the number of revolutions of the pump of the cooling water circulation path for free cooling, a connection part on a feed path side of the cooling circuit for free cooling, and a heat exchanger or heat storage tank for the free cooling A cooling medium cooling refrigeration facility, further comprising: a second flow meter provided between the return pipe end and controlling the number of revolutions of the pump of the cooling circuit for free cooling.

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