JP2012127573A - Heat source system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat source system whose total power consumption becomes minimum, and to provide a method of controlling the same.SOLUTION: The heat source system 10 includes: a heat pump; an underground heat exchanger 20; a cooling tower 30; a heat source water pump; a switching means of switching and connecting one of the cooling tower and the heat exchanger in a parallel or series operation mode; a simulator 82 which calculates a heat pump load and a heat source water load, selects one operation mode of cooling capability or heating capability above the heat source water load, and calculates optimum values of a heat source water flow rate ratio of the cooling tower, a heat source water flow rate ratio of the heat exchanger, and an air capacity ratio of a cooling tower fan, which minimize a system power consumption, among system power consumptions calculated by varying the heat source water flow rate ratio of the cooling tower, the heat source water rate ratio of the heat exchanger, and the air capacity ratio of the cooling tower fan 32; and a control means 80 of performing control to a flow rate ratio of the cooling tower or the heat exchanger and an air capacity ratio of the cooling tower fan based upon the minimum system power consumption.

Description

  The present invention relates to a hybrid heat source system that uses geothermal heat to save energy by using geothermal heat.

  There is an air conditioning system that can suppress the emission of global warming gases such as carbon dioxide, and can produce cold water while reducing energy consumption using geothermal heat, which is a constant temperature throughout the year, as a heat source. In recent years, air-conditioning systems using geothermal heat as a heat source have been promoted from the viewpoint of energy saving and environmental load reduction.

In such an air conditioning system, Patent Document 1 discloses an air conditioning system having a high COP in which the use of underground heat and outside air heat is selectively used based on high efficiency.
The air conditioning system of Patent Document 1 incorporates an air heat exchanger in a heat pump that uses geothermal heat, and in the case of cooling in the summer, when the underground temperature is higher than the outside air temperature, in the winter heating use, the underground temperature is outside air. When it is lower than the temperature, the circulation on the underground heat source side is stopped and the air heat source side heat pump is operated.

JP 2009-250555 A

However, in the conventional heat pump system using geothermal heat, the amount of heat exchanged in the geothermal heat exchanger is small, so the operation method is switched according to the load, such as switching between conventional outside air use and combined use of outside air and underground heat. There is a need. At this time, since there is energy consumption for operating auxiliary equipment such as air heat source equipment and supply pumps other than the air conditioner, it is necessary to consider energy consumption of the entire system rather than partial energy consumption.
Accordingly, an object of the present invention is to provide a heat source system in which the power consumption of the entire system is minimized.

  The heat source system of the present invention includes a heat pump, a heat exchanger that produces heat source water that exchanges heat with underground heat and supplies the heat pump, and the heat source that exchanges heat with outside air using a cooling tower fan and supplies the heat pump A cooling tower for producing water, a heat source water pump for supplying the heat source water to the heat pump, and switching the connection between the cooling tower and the heat exchanger with respect to the heat pump in one or a parallel or series operation mode Switching means for calculating, a heat pump load and a heat source water load, selecting the operation mode of the cooling capacity or the heating capacity equal to or higher than the heat source water load, the heat source water flow ratio of the cooling tower and the heat source of the heat exchanger The heat source water flow ratio of the cooling tower and the heat exchanger that are the smallest among the system power consumption calculated by changing the water flow ratio and the air flow ratio of the cooling tower fan A simulator for calculating the optimum value of the heat source water flow rate ratio and the cooling tower fan air flow ratio, the flow rate ratio of the cooling tower or the heat exchanger based on the minimum system power consumption, the air flow ratio of the cooling tower fan And a control means for controlling.

In this case, the switching means may perform heat exchange by circulating the heat source water between the cooling tower and the heat exchanger.
The heat pump may include a heat pump refrigerator that produces cold water, and a cold water pump that conveys the cold water.
Further, the simulator has a database created in advance, the amount of heat radiated to the cold water, the outdoor wet bulb temperature, the frequency of the inverter from the database according to the underground temperature of the heat exchanger, and the heat source water flow ratio, The cooling tower air volume ratio may be extracted.

The database is a control table showing a relative relationship between the inverter set values according to the amount of heat radiated to the cold water, the outside wet bulb temperature, and the underground temperature of the heat exchanger, and radiates heat to the assumed cold water. For the amount of heat and outside air wet bulb temperature, the ground temperature of the heat exchanger, the heat source water inlet temperature of the heat exchanger, the heat source water flow rate, and the cooling tower air volume are changed repeatedly to calculate the consumption of the entire system. It is preferable that an inverter frequency at which energy is minimized, a heat source water flow rate ratio, and a cooling tower air volume ratio are provided as set values.
In this case, the database may be a control table indicating a relative relationship among the wet bulb temperature, the cold water load, the underground temperature, and the operation mode.

  According to the heat source system of the present invention having the above configuration, it is possible to select a plurality of connection forms of the cooling tower and the heat exchanger with respect to the refrigerator, the operation range of the constituent devices is obtained by simulation, and the power consumption of the entire heat source system is minimized. The operation mode to be selected, the cooling water pump, the cooling tower fan inverter frequency, and the opening and closing of the valves are determined and controlled at their optimum values. For this reason, the total power consumption of the cooling water pump, the cooling tower fan, and the refrigerator constituting the system can be reduced, and energy saving of the entire system can be achieved.

  In addition, by circulating the cooling water between the cooling tower and the heat exchanger, if heat is dissipated excessively in the heat exchanger and it is necessary to dissipate heat to the outside of the heat exchanger, heat is exchanged with the cooling tower. By performing the exchange, the performance of the heat exchanger can be restored.

It is a figure showing the composition outline of the heat source system of the present invention. It is explanatory drawing of the operation mode 1 of a heat source system. It is explanatory drawing of the operation mode 2 of a heat source system. It is explanatory drawing of the operation mode 3 of a heat source system. It is explanatory drawing of the operation mode 4 of a heat source system. It is explanatory drawing of the operation mode 5 of a heat source system. It is a processing flow of the control method of the heat source system of this invention. It is explanatory drawing of the operating method table of a heat source system. It is explanatory drawing of the setting value table of a heat source system. It is explanatory drawing of the setting value table of a heat source system. It is a figure which shows the structure outline of the modification of a heat source system.

The heat source system of the present invention will be described in detail below with reference to the accompanying drawings.
FIG. 1 is a diagram showing a schematic configuration of a heat source system of the present invention. As shown, the heat source system 10 of the present invention includes a refrigerator 20, a cooling tower 30, a heat exchanger 40, first and second cooling water supply means 50 and 60, cold water supply means 70, and control means. 80 is the main basic configuration. In the present embodiment, a refrigerator will be described below as an example of a heat pump.

  The refrigerator 20 includes a condenser, an evaporator, a compressor, and a decompression chamber. The gaseous refrigerant whose pressure has been increased by the compressor is pushed into the condenser. The condenser then takes heat away from the pressurized refrigerant. The cooling water flowing through the condenser becomes hot when it takes heat and flows out. On the other hand, the evaporator takes heat of cold water when the refrigerant evaporates.

In the present invention, the cooling water whose temperature has been increased by cooling a condenser (not shown) in the refrigerator 20 is cooled using the cooling tower 30 or the heat exchanger 40 in order to lower the temperature.
The cooling tower 30 includes a cooling tower fan 32. When the cooling tower 30 is brought into contact with the outside air, the cooling water itself evaporates. At this time, the temperature of the cooling water can be lowered by taking heat from the surrounding water by the latent heat of evaporation. The cooling tower 30 shown in FIG. 1 is an open type, and heat is exchanged with outside air to produce cooling water.

  The heat exchanger 40 inserts a pipe called a U tube 42 inside a steel pipe pile buried in the ground, and uses a heat medium (cooling water or the like) for heat transfer with the ground as a pile between the pile and the U tube 42. It is configured by filling the interval part. By installing the heat exchanger 40 in the ground where the temperature is constant throughout the year, the cooling water for the heat pump (hereinafter abbreviated as HP) type refrigerator is circulated to the heat exchanger 40 to exchange heat with the ground. Manufacturing cooling water.

The heat source system 10 of the present invention includes a first cooling water supply means 50 in which cooling water serving as heat source water flows between the refrigerator 20 and the cooling tower 30, and cooling water flows between the refrigerator 20 and the heat exchanger 40. Second cooling water supply means 60 is formed.
The first cooling water supply means 50 has a first feed pipe 52, a first return pipe 54, and a cooling water pump 56 as the main basic configuration.

  The first feed pipe 52 is a pipe that connects the cooling water outlet of the refrigerator 20 and the cooling water inlet of the cooling tower 30. The cooling water pump 56, the first flow meter 57, and the first thermometer 91 are provided in the middle of the piping. And first and second two-way valves 101, 102. The first two-way valve 101 is attached to the cooling water outlet side of the refrigerator 20. The first two-way valve 101 can control the supply of cooling water by closing or opening the pipe (the same applies to the second to ninth opening valves 102 to 109 below). The second two-way valve 102 is attached to the cooling water inlet side of the cooling tower 30. In the first feed pipe 52, a first temperature sensor 91, a cooling water pump 56, and a first flow meter 57 are attached between the first and second two-way valves 101, 102 from the refrigerator 20 side. The cooling water pump 56 includes a first inverter 58 that can arbitrarily adjust the frequency, and a first wattmeter 59 that can measure the power consumption of the first inverter 58. The cooling water pump 56 is configured to supply cooling water from the refrigerator 20 to the cooling tower 30, and the first flow meter 57 can measure the flow rate of the cooling water flowing through the first feed pipe 52. The first thermometer 91 can measure the cooling water outlet temperature of the refrigerator 20.

  The first return pipe 54 is a pipe that connects the cooling water outlet of the cooling tower 30 and the cooling water inlet of the refrigerator 20, and the third to fifth two-way valves 103, 104, 105, Three temperature sensors 92 and 93 are provided. A first bypass pipe 53 that connects both the first feed pipe 52 and the first return pipe 54 is attached. Specifically, the first bypass pipe 53 includes a first feed pipe 52 between the first two-way valve 101 and the cooling water pump 56, and a first return pipe 54 between the fourth and fifth two-way valves 104 and 105. Connected. A sixth two-way valve 106 is attached to the first bypass pipe 53. The second temperature sensor 92 can measure the cooling water outlet temperature of the cooling tower 30. The third thermometer 93 can measure the cooling water inlet temperature of the refrigerator 20.

The 2nd cooling water supply means 60 has the 2nd feed piping 62 and the 2nd return piping 64 as the main basic composition.
The second feed pipe 62 is a pipe connecting the first feed pipe 52 between the first flow meter 57 and the second two-way valve 102 and the cooling water inlet of the heat exchanger 40, and the electromagnetic two-way valve 66; A seventh two-way valve 107, a second flow meter 67, and a fourth thermometer 94 are provided. The electromagnetic two-way valve 66 can adjust the flow rate of the cooling water flowing from the first feed pipe 52 to the second feed pipe 62 based on a control signal of the control means 80 described later. The second flow meter 67 can measure the flow rate of the cooling water flowing through the second feed pipe 64. The fourth temperature sensor 94 can measure the cooling water inlet temperature of the heat exchanger 40.

  The second return pipe 64 is a pipe connecting the cooling water outlet of the heat exchanger 40 and the first return pipe 54 between the connection points of the fourth two-way valve 104 and the first bypass pipe 53, and the eighth two-way pipe. A valve 108 is provided.

  A second bypass pipe 68 that connects the first return pipe 54 and the second feed pipe 62 is attached to the first and second cooling water supply means 50 and 60. Specifically, the second bypass pipe 68 includes a first return pipe 54 between the third and fourth two-way valves 103 and 104, and a second feed pipe between the seventh two-way valve 107 and the second flow meter 67. 62 is connected. The second bypass pipe 68 has a ninth two-way valve 109 attached thereto.

  A cold water supply means 70 is connected to an evaporator (not shown) of the refrigerator 20. The cold water supply means 70 has a third basic configuration including a third feed pipe 72, a third return pipe 74, and a cold water pump 76.

  The third feed pipe 72 is connected to the cold water outlet of the refrigerator 20, and a fifth temperature sensor 95 is attached in the middle of the pipe. The fifth temperature sensor 95 can measure the cold water outlet temperature of the refrigerator 20. The third return pipe 74 is connected to the cold water inlet temperature of the refrigerator 20, and a cold water pump 76, a third flow meter 77, and a sixth thermometer 96 are attached in the middle of the pipe. The cold water pump 76 includes a second inverter 78 whose frequency can be arbitrarily adjusted, and a second wattmeter 79 capable of measuring the power consumption of the second inverter 78. The cold water pump 76 is configured to supply cold water from the outside to the refrigerator 20, and the third flow meter 77 can measure the flow rate of cold water flowing through the third return pipe 74. The sixth thermometer 96 can measure the cold water inlet temperature of the refrigerator 20.

  A third inverter 33 and a third wattmeter 34 are attached to the cooling tower fan 32. A fourth wattmeter 22 is attached to the refrigerator 20. A seventh temperature sensor 97 capable of measuring the underground temperature is attached to the heat exchanger 40. The heat source system 10 is provided with an eighth temperature sensor 98 that can measure the temperature of the outside air and a humidity sensor 99 that can measure the humidity of the outside air.

  The control means 80 includes first to eighth temperature sensors 91 to 98, a humidity sensor 99, first to third inverters 58, 78, 33, first to ninth two-way valves 101 to 109, electromagnetic two The cooling valve 30 is electrically connected (not shown) to the direction valve 66, the first to third flow meters 57, 67, 77, and the first to fourth watt meters 59, 79, 34, 22. Of the cooling water flow rate of the cooling tower 30, the cooling water flow rate ratio of the heat exchanger 40 and the air flow rate ratio of the cooling tower fan 32, the simulator 82 for obtaining the optimum value, the cooling water flow rate ratio of the cooling tower 30 obtained by the simulator 82 and the heat exchanger 40 The controller 84 that outputs the optimum value of the cooling water flow rate ratio and the air flow rate ratio of the cooling tower fan 32 and the storage circuit 86 have a main basic configuration.

The simulator 82 simulates the control by the control means 80 and calculates the power consumption of the heat source system 10 as a whole.
In the control means 80, measured values of various sensors on the system necessary for obtaining the optimum values of the cooling water flow ratio of the cooling tower 30, the cooling water flow ratio of the heat exchanger 40, and the air flow ratio of the cooling tower fan 32 are stored. Entered. Specifically, the measured temperature of the first to eighth temperature sensors 91 to 98, the measured humidity of the humidity sensor 99, the measured power consumption of the first to fourth wattmeters 59, 79, 34, 22 and the first to third flow rates. A total of 57, 67, and 77 measured flow rates are input.

Next, the operation mode of the heat source system 10 of the present invention having the above configuration will be described below.
FIG. 2 is an explanatory diagram of the operation mode 1 of the heat source system.
In operation mode 1 of the heat source system 10, only the cooling tower 30 is supplied with the cooling water of the refrigerator 20. Specifically, the first to fifth two-way valves 101 to 105 are opened, and the sixth to ninth two-way valves 106 to 109 and the electromagnetic two-way valve 66 are closed. In the heat source system 10 having such a configuration, the cooling water heated by the refrigerator 20 is supplied from the first feed pipe 52 of the first cooling water supply means 50 to the cooling water inlet of the cooling tower 30. The cooling water cooled by the cooling tower 30 is supplied from the first return pipe 54 to the cooling water inlet of the refrigerator 20. This operation mode can be applied when the outside air temperature decreases.

FIG. 3 is an explanatory diagram of the operation mode 2 of the heat source system.
In operation mode 2 of the heat source system 10, only the heat exchanger 40 supplies the cooling water of the refrigerator 20. Specifically, the first, seventh, eighth, and fifth two-way valves 101, 107, 108, and 105 and the electromagnetic two-way valve 66 are opened, and the second, third, fourth, sixth, and ninth are opened. The two-way valves 102-104, 106, 109 are closed. In the heat source system 10 having such a configuration, the cooling water heated by the refrigerator 20 cools the heat exchanger 40 from the first feed pipe 52 of the first coolant supply means 50 via the second feed pipe 62. Supplied to the water inlet. The cooling water cooled by the heat exchanger 40 is supplied from the second return pipe 64 to the cooling water inlet of the refrigerator 20 via the first return pipe 54. This operation mode can be applied when the underground temperature is lower than the outside air.

FIG. 4 is an explanatory diagram of the operation mode 3 of the heat source system.
In operation mode 3 of the heat source system 10, the cooling water of the refrigerator 20 is supplied to the cooling tower 30 and the heat exchanger 40 in parallel. Specifically, the sixth and ninth two-way valves 106 and 109 are closed, and the other two-way valves 101 to 105, 107 and 108 and the electromagnetic two-way valve 66 are opened. In the heat source system 10 having such a configuration, the cooling water heated by the refrigerator 20 is supplied from the first feed pipe 52 of the first cooling water supply means 50 to the cooling water inlet of the cooling tower 30. The cooling water cooled by the cooling tower 30 is supplied from the first return pipe 54 to the cooling water inlet of the refrigerator 20. The cooling water heated by the refrigerator 20 is supplied from the first feed pipe 52 of the first coolant feed means 50 to the coolant inlet of the heat exchanger 40 via the second feed pipe 62. The cooling water cooled by the heat exchanger 40 is supplied from the second return pipe 64 to the cooling water inlet of the refrigerator 20 via the first return pipe 54. Thus, parallel operation in which cooling water flows through the heat exchanger 40 and the cooling tower 30 can be performed. At this time, it is possible to control the flow rate ratio branched to the heat exchanger 40 and the cooling tower 30 by adjusting the opening degree of the electromagnetic flow valve 66.

FIG. 5 is an explanatory diagram of the operation mode 4 of the heat source system.
The operation mode 4 of the heat source system 10 supplies the cooling water of the refrigerator 20 to the cooling tower 30 and the heat exchanger 40 in series. Specifically, the fourth, sixth, and seventh two-way valves 104, 106, and 107 and the electromagnetic two-way valve 66 are closed, and the other two-way valves 101 to 103, 105, 108, and 109 are opened. . In the heat source system 10 having such a configuration, the cooling water heated by the refrigerator 20 is supplied from the first feed pipe 52 of the first cooling water supply means 50 to the cooling water inlet of the cooling tower 30. The cooling water cooled in the cooling tower 30 is supplied from the first return pipe 54 to the cooling water inlet of the heat exchanger 40 from the second feed pipe 62 via the second bypass pipe 68. The cooling water cooled by the heat exchanger 40 is supplied from the second return pipe 64 to the cooling water inlet of the refrigerator 20 via the first return pipe 54. In this way, a series operation in which cooling water flows from the cooling tower 30 to the heat exchanger 40 can be performed. The operation mode 3 can reduce the temperature of cooling water most efficiently.

FIG. 6 is an explanatory diagram of the operation mode 5 of the heat source system.
In operation mode 5 of the heat source system 10, the supply of the cooling water of the refrigerator 20 is stopped and the cooling water is circulated between the cooling tower 30 and the heat exchanger 40. Specifically, the first, fourth, seventh, and fifth two-way valves 101, 104, 107, and 105 and the electromagnetic two-way valve 66 are closed, and the other two-way valves 102, 103, 106, 108, and 109 are closed. Is open. In the heat source system 10 having such a configuration, the cooling water cooled by the cooling tower 30 is supplied from the first return pipe 54 via the second bypass pipe 68 to the cooling water inlet of the heat exchanger 40 from the second feed pipe 62. Supplied to. The cooling water heated by the heat exchanger 40 is supplied from the second return pipe 64 to the first return pipe 54 and supplied from the first feed pipe 52 to the cooling water inlet of the cooling tower 30 via the first bypass pipe 53. Is done. In such an operation mode 5, heat is exchanged by performing heat exchange with the cooling tower 30 when heat is excessively dissipated in the heat exchanger 40 and it is necessary to dissipate heat to the outside of the heat exchanger 40. This is to recover the performance of the heat exchanger 40 and can be used mainly when the performance of the heat exchanger 40 is deteriorated.

In the present embodiment, the first to ninth two-way valves 101 to 109 are used as switching means for switching and connecting the cooling tower 30 and the heat exchanger 40 to the refrigerator 20 in one or a parallel or series operation mode. The electromagnetic release valve 66 is used.
In the present invention, the operation method of the operation modes 1 to 4 is switched by the control means 80 so that the power consumption is minimized, and the operation mode 5 is switched when the performance of the heat exchanger 40 is recovered.

  Next, an operation method of the heat source system 10 using a heat pump using geothermal heat as a heat source will be described below. FIG. 7 shows a process flow of the control operation of the heat source system 10 of the present invention.

  First, the first to third flow meters 57, 67, 77 are used for the cooling water flow rate LL1, LL2, the cold water flow rate L, and the sixth and fifth temperature sensors 96, 95 are used for the refrigerator cold water inlet temperature Tcw1, the refrigerator cold water outlet temperature Tcw2. The third and first temperature sensors 93 and 91, the refrigerator cooling water inlet temperature Tcwd1, the refrigerator cooling water outlet temperature Tcwd2, the eighth temperature sensor 98, the humidity sensor 99, the outside air temperature Ta, the outside air humidity RH, Underground temperature Ts is measured by 7 temperature sensor 97.

These measured values are input to the control system 80, and the simulator 82 calculates the chilled water load Q1 and the chilled water load Q2 (step 1).
The chilled water load Q1 can be calculated by the following equation using the measured chilled water flow rate L, the refrigerator cold water inlet temperature Tcw1, the refrigerator cold water outlet temperature Tcw2, Cw (cold water specific heat), and ρw (cold water density).

  The cooling water load Q2 is calculated by the following equation using the measured cooling water flow rate LL1, refrigerator cooling water inlet temperature Tcwd1, refrigerator cooling water outlet temperature Tcwd2, Cw (cold water specific heat), and ρw (cold water density). be able to.

Next, an optimum operation mode is selected from the calculated values using the simulator 82 (step 2).
There are five operation modes in the present invention. As shown in FIGS. 2 to 6, in this embodiment, operation mode 1: cooling tower operation, operation mode 2: heat exchanger operation, operation mode 3: cooling tower and heat exchanger. Parallel operation, operation mode 4: series operation of cooling tower and heat exchanger, operation mode 5: cooling water circulation operation of cooling tower and heat exchanger.

  Regarding the determination of the operation mode, using the cooling water load Q2, the cooling water flow rates LL1, LL2, the refrigerator cooling water outlet temperature Tcwd2, the underground temperature Ts, the outside air temperature Ta, and the outside air humidity RH, The processing capacity (cooling capacity) of the operation mode when the cooling water pump 56 and the cooling tower fan 32 perform the rated operation is calculated (step 3).

This calculation is performed for operation modes 1 to 5 (step 4).
Then, an operation mode in which the processing capacity is equal to or higher than the cooling water load Q2 and the power consumption is the smallest is determined (step 5).
After determining the operation mode, the first to ninth two-way valves 101 to 109 or the electromagnetic two-way valve 66 are opened and closed via the controller 84 to switch the operation method.

Next, optimum value control in each operation mode will be described below.
In the cooling tower operation of the operation mode 1, the cooling tower cooling water outlet temperature is calculated while changing the cooling water flow rate ratio of the cooling tower 30 and the air flow ratio of the cooling tower fan 32 by several percent.

In the heat exchanger operation of the operation mode 2, the heat exchanger cooling water outlet temperature is calculated while changing the cooling water flow rate ratio of the heat exchanger 40 by several percent.
In the parallel operation of the cooling tower and the heat exchanger in the operation mode 3, the cooling water flow rate ratio of the cooling tower 30, the cooling water flow rate ratio of the heat exchanger 40, and the air flow ratio of the cooling tower fan 32 are changed by several percent. The cooling tower cooling water outlet temperature and the heat exchanger cooling water outlet temperature are calculated.

  In the serial operation of the cooling tower and the heat exchanger in the operation mode 4, in the cooling tower operation, the cooling water flow ratio of the cooling tower 30 (= the cooling water flow ratio of the heat exchanger 40) and the air flow ratio of the cooling tower fan 32 are several percent. While changing the temperature step by step, calculate the heat exchanger cooling water outlet temperature.

  After the operation mode is determined, the cooling water flow ratio of the cooling tower 30, the cooling water flow ratio of the heat exchanger 40, and the air flow ratio of the cooling tower fan 32 are changed by several percent by the above method (step 6). ) And calculate an optimum value (step 7).

Then, the refrigerator cooling water inlet temperature Tcwd1 of the refrigerator 20 is calculated (step 8).
In the operation modes 1, 2, and 4, the calculated cooling tower cooling water outlet temperature or heat exchanger cooling water outlet temperature becomes the refrigerator cooling water inlet temperature Tcwd1.

  When the cooling tower 30 and the heat exchanger 40 in the operation mode 3 are operated in parallel, the refrigerator cooling water inlet temperature Tcwd1 is the cooling tower side cooling water flow rate LL_CT, the cooling tower side cooling water outlet temperature Tout_ct, and the heat exchanger side cooling. It can be calculated by the following equation using the water flow rate LL_HEX and the heat exchanger side cooling water outlet temperature Tout_hex.

The refrigerator COP corresponding to the refrigerator cooling water inlet temperature Tcwd1 and the cold water load Q1 is calculated (step 9). The relationship between the coolant temperature, the load Q1, and the refrigerator COP is estimated based on a known performance curve of the refrigerator itself.
Then, the refrigerator power consumption W0 is calculated from the refrigerator COP and the cold water load Q1 by the following equation.

  The system power consumption Wsys and the system COP (SCOP) obtained by adding the chiller power consumption W0 to the chilled water pump power consumption W1, the cooling water pump power consumption W2, and the cooling tower fan power consumption W3 are obtained by the following equations.

  The Wsys and the system COP are calculated each time for the cooling water flow ratio of the cooling tower 30, the cooling water flow ratio of the heat exchanger 40, and the air flow ratio of the cooling tower fan 32, and Wsys is minimized (system COP is maximized). Each flow rate ratio and air volume ratio are calculated (step 10).

  The above ratio is converted by the simulator 82 into the inverter frequency f_pump of the cooling water pump 56 and the inverter (INV) frequency f_fan of the cooling tower fan 32 using the following equations.

となる。 Here in operation mode 1

It becomes.

となる。 In operation modes 2 and 4,

It becomes.

The inverter frequency f_pump of the cooling water pump 56 is

と表すことができる。 The inverter (INV) frequency f_fan of the cooling tower fan 32 is

It can be expressed as.

  Here, F is the rated frequency (50 Hz or 60 Hz), rate_pump is the cooling water pump flow rate ratio, rate_fan is the cooling tower fan air volume ratio, and LL0 is the cooling water pump flow rate at the rated frequency.

  These frequencies are output via the controller 84 to operate the pump and fan. When the system branches as in the parallel operation of the operation mode 3, the cooling water flow rate ratio of the cooling tower 30 and the cooling water flow rate ratio of the heat exchanger 40 calculated above are set by the electromagnetic two-way valve. Control is performed (step 11).

  The calculation of the processing flow of the control operation of the heat source system shown in FIG. 7 is performed with respect to the assumed wet bulb temperature (converted from the outside air temperature and outside air humidity), the underground temperature and the load, and the obtained operation mode and optimum value. Table processing can reduce the processing of the control method.

  FIG. 8 is an explanatory diagram of an operation method table of the heat source system. Specifically, FIG. 8 is a database showing operating modes 1 to 5 in which the vertical axis indicates the cold water load, the horizontal axis indicates the wet bulb temperature, and the optimum values based on each cold water load and wet bulb temperature. .

The table shown in FIG. 8 is data created for an arbitrary underground temperature. Such a table can be created for each arbitrary underground temperature.
9 and 10 are explanatory diagrams of a set value table of the heat source system. Specifically, the vertical axis of FIGS. 9 and 10 represents the cold water load, and the horizontal axis represents the wet bulb temperature.

FIG. 9 shows the cooling water pump inverter frequency (Hz), the cooling tower fan inverter frequency (Hz), and FIG. 10 shows the heat exchanger cooling water flow rate based on each cold water load, wet bulb temperature, and underground temperature of the heat exchanger 40. Ratio (%), cooling tower cooling water flow ratio (%), cooling tower airflow ratio (%), refrigerator cooling water inlet temperature Tcwd1 (° C.), cooling tower cooling water outlet temperature (° C.), heat exchanger cooling water outlet It is a database showing temperature (° C.).
Here, the heat exchanger cooling water flow rate ratio (%) and the cooling tower cooling water flow rate ratio (%) are obtained by dividing the respective flow rates by the rated flow rate of the cooling water pump 56 (flow rate at the rated frequency).

The heat exchanger flow rate ratio (%) and cooling tower cooling water flow rate ratio (%) in FIG. 10 correspond to the operation mode in FIG. That is, when the operation mode is 1, since the cooling water does not flow through the heat exchanger, the heat exchanger cooling water flow rate ratio is 0. When the operation mode is 2, since the cooling water does not flow through the cooling tower, the cooling tower cooling water flow rate ratio is zero. When the operation mode is 3, since it flows in parallel with the heat exchanger and the cooling tower, the ratio of the flow rate flowing through each is described. In the case of the operation mode 4, since it flows in series with a heat exchanger and a cooling tower, the ratio of the flow volume which flows through each is equal, and the ratio is indicated.
The control tables of FIGS. 9 and 10 are created for a certain underground temperature, and the above-described control tables exist for a plurality of underground temperatures.

A simulation is performed in advance based on the calculation flow of FIG. 7, and the storage circuit 86 of the control means 80 is stored with the optimum values as shown in FIGS. Such cold water load was calculated from the measured value by the database QQ1, ambient air wet bulb temperature T _WB, the cooling water flow rate corresponding to the ground temperature Ts, reads from stores an optimum value of the cooling tower fan flow in the storage circuit 86 table The inverter frequency (cooling tower fan 32, cooling water pump 56) is calculated by the simulator 82. Then, it is output to the inverter 78 of the chilled water pump 76, the electromagnetic two-way valve 66, the inverter 58 of the cooling water pump 56, and the inverter 33 of the cooling tower fan 32 via the controller 84, and heat exchange is performed by opening and closing the electromagnetic two-way valve 66. The operation with the lowest power consumption can be performed by controlling the cooling water flow rate ratio (%), cooling tower cooling water flow rate ratio (%), and cooling tower air flow rate ratio (%) to the ratio read from the table. it can.

  The first to fourth wattmeters 59, 79, 34, and 22 measure actual power consumption values of the refrigerator 20, the cooling water pump 56, the cooling water pump 76, and the cooling tower fan 32 predicted by the simulator 82. A correction coefficient at the time of calculation can be obtained using the actually measured value and the calculated value. Reflecting the correction coefficient when calculating the optimum value in the simulator 82 or creating table data or the like makes it possible to improve the calculation accuracy in the simulator 82.

  Here, in the cooling tower, an error may occur between the calculated value and the actually measured value due to the influence of aging degradation or the like. Therefore, in order to obtain a correction coefficient for increasing calculation accuracy, a temperature sensor 92 is installed at the outlet of the cooling tower and the outlet temperature is measured.

  Further, when the heat source system 10 shown in FIG. 1 uses an open type cooling tower 30, the cooling water is released to the atmosphere when passing through the cooling tower 30. However, when using a medium that needs to avoid diffusion to the atmosphere due to opening to the cooling water (for example, antifreeze liquid with a freezing point of less than 0 ° C is used to prevent freezing. In addition, in the case of a liquid that is generated and diffusion to the atmosphere may not be preferable, a closed cooling tower can be used instead of the open type.

  Next, a modified example of the heat source system 10 of the present invention will be described. FIG. 11 is a diagram showing a schematic configuration of a modification of the heat source system. As shown in the drawing, the heat source system 100 according to the modification is a case where a heat exchange means 120, a cooling water pump 122, and a pipe 130 are added to the open cooling tower 30 of the heat source system 10. The other configuration is the same as that of the heat source system 10 shown in FIG. 1, and detailed description thereof is omitted.

  When an antifreeze liquid is used for the cooling water of the refrigerator 20, the antifreeze liquid is used in the refrigerator 20, the heat exchanger 40, and the first and second cooling water supply means 50 and 60 of the heat exchange means 120. On the other hand, the cooling water is circulated in the path of the open type cooling tower 30, the heat exchange means 120, the cooling water pump 122, and the piping 130, and the cooling water is produced in the cooling tower 30. Then, the cooling water is cooled by exchanging heat with the antifreeze liquid (cooling machine cooling water) by the heat exchanging means 120.

According to the heat source system 100 of such a modification, the antifreeze liquid can be cooled without opening to the atmosphere. Note that the operation modes 1 to 5 can be applied to the heat source system 100 of the modified example.
The heat source system of the present invention can be applied not only to a refrigerator but also to other heat exchanging means including a heat pump capable of heat transfer using a heat medium.

10 ......... Heat source system, 20 ......... Refrigerator, 22 ......... 4th electricity meter, 30 ......... Cooling tower, 32 ......... Cooling tower fan, 33 ......... Third inverter, 34 ......... 3rd wattmeter, 40 ......... heat exchanger, 42 ......... U tube, 50 ......... first cooling water supply means, 52 ......... first feed pipe, 53 ......... first bypass pipe, 54 ......... First return pipe, 56 ......... Cooling water pump, 57 ......... First flow meter, 58 ......... First inverter, 59 ......... First power meter, 60 ......... Second cooling water Supply means 62 ......... Second feed pipe 64 ......... Second return pipe 66 ......... Electromagnetic two-way valve 67 ......... Second flow meter 68 ......... Second bypass pipe 70 ... ...... Cooling water supply means 72 ......... Third feed piping 74 ......... Third return piping 76 ......... Cooling water pump 77 ......... Third flow meter 78 ...... Second inverter, 79 ......... Second wattmeter, 80 ......... Control means, 82 ......... Simulator, 84 ......... Controller, 86 ......... Memory circuit, 91 ......... First temperature sensor, 92 ......... Second temperature sensor, 93 ......... Third temperature sensor, 94 ......... Fourth temperature sensor, 95 ......... Fifth temperature sensor, 96 ......... Sixth temperature sensor, 97 ......... No. 7 temperature sensor, 98 ......... 8th temperature sensor, 99 ......... Humidity sensor, 101 ......... First two-way valve, 102 ......... Second two-way valve, 103 ......... Third two-way valve, 104 ......... 4th two-way valve, 105 ......... 5th two-way valve, 106 ......... 6th two-way valve, 107 ......... 7th two-way valve, 108 ......... 8th two-way valve, 109 ……… The ninth two-way valve.

Claims (6)

A heat pump,
A heat exchanger that produces heat source water that exchanges heat with underground heat and supplies the heat pump;
A cooling tower for producing heat source water to be supplied to the heat pump by exchanging heat with outside air by a cooling tower fan;
A heat source water pump for supplying the heat source water to the heat pump;
Switching means for switching and connecting the cooling tower and the heat exchanger to the heat pump in one or parallel or series operation mode;
Calculate the heat pump load and the heat source water load, select the operation mode of the cooling capacity or the heating capacity that is equal to or higher than the heat source water load, the heat source water flow ratio of the cooling tower, the heat source water flow ratio of the heat exchanger, and the Optimum heat source water flow rate ratio of the cooling tower, heat source water flow rate ratio of the heat exchanger, and air flow ratio of the cooling tower fan that are the smallest among the system power consumption calculated by changing the air flow ratio of the cooling tower fan A simulator that calculates the value,
Control means for controlling the flow rate ratio of the cooling tower or the heat exchanger and the air flow ratio of the cooling tower fan based on the system power consumption that is minimized;
A heat source system comprising:   The heat source system according to claim 1, wherein the switching unit performs heat exchange by circulating the heat source water between the cooling tower and the heat exchanger. The heat pump
A heat pump refrigerator that produces cold water;
A cold water pump for conveying the cold water;
The heat source system according to claim 1 or 2, further comprising:   The simulator has a database created in advance, the frequency of the inverter from the database according to the amount of heat radiated to the cold water, the outside air wet bulb temperature, the underground temperature of the heat exchanger, and the heat source water flow ratio The heat source system according to claim 3, wherein a cooling tower air volume ratio is extracted.   The database is a control table showing the relative relationship of the inverter set values according to the amount of heat radiated to the cold water, the outside wet bulb temperature, and the underground temperature of the heat exchanger, and is radiated to the cold water assumed in advance. The amount of heat and the outside air wet bulb temperature were changed by changing the underground temperature in the heat exchanger, the heat source water inlet temperature of the heat exchanger, the heat source water flow rate, and the cooling tower air volume, The heat source system according to claim 4, wherein an inverter frequency at which energy consumption is minimized, a heat source water flow rate ratio, and a cooling tower air volume ratio are provided as set values.   The heat source system according to claim 4, wherein the database is a control table indicating a relative relationship among a wet bulb temperature, a cold water load, an underground temperature, and an operation mode.

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