JP2013204833A - Heating medium piping system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce pump power by separating a control of a center-side secondary pump and a local control.SOLUTION: A heating medium piping system includes a primary pump which circulates hot and cold water on the side of a heat source machine, and a secondary pump which circulates the hot and cold water to an air conditioner side, and is equipped with an air conditioner piping system for independently conditioning air in a plurality of areas, and a heat medium main conveyance loop. A distribution pump and a two-way valve are provided in each load side temperature control piping system. The rotation speed of the distribution pump and the opening degree of the valve are controlled, by using a signal obtained by calculating measured signal of a load-side control target temperature as two ratio biases. In controlling temperatures of the air conditioner, the rotation speed of an inverter of the air conditioner pump is adjusted in preference to the opening degree of the two-way valve.

Description

  The present invention relates to a heat medium piping system for supplying a heat medium such as cold water or hot water in air conditioning equipment of buildings such as buildings and factories.

As is well known, a plurality of air conditioners are provided in a building such as an office building where a plurality of stores and offices occupy, and each air conditioner is provided with a heat source machine such as a refrigerator or a cold / hot water generator. After the cooled or heated heat medium such as cold water and hot water is sent to the coil of each air conditioner by the pump and returned to the heat source machine, it is circulated so that the room or zone (air conditioner) The heat medium is supplied to the heat load in the region at a flow rate corresponding to the heat exchange in the coil, and cooling and heating are performed.
Conventionally, in building air conditioning equipment, it is most common to control the heat medium flow rate with a two-way valve provided for each coil of the air conditioner in order to properly handle different heat loads for each air conditioner by heat exchange with the heat medium When transporting cold / hot water from the heat source unit to the air conditioner, the primary pump responsible for the pressure loss of the heat source unit and the surrounding pressure loss of the heat source unit, the heat load side pressure loss of the air conditioner etc. and the long pipe system pressure loss The heat medium circulation system is shared with the secondary pumps responsible for this, and both the primary pump and the secondary pump are installed in the machine room to feed water in one batch and are installed individually for each air conditioner (or for each air conditioner group). By changing the flow rate of the heat medium in each coil by adjusting the opening of the valve, it was possible to cope with fluctuations in the heat load.

In this case, in order to reduce the power of the secondary pump in accordance with the restriction of the two-way valve, secondary pump variable flow rate (inverter) control that makes the return differential pressure constant is often adopted. However, in the inverter control that keeps the return differential pressure at a certain value, only the flow rate of the secondary pump is controlled and the head is constant, so that the pump rotation speed can be lowered at the partial load when the heat load is small. The range is small and the pump power reduction effect is small.
Therefore, by storing various parameters and performing secondary pump control that performs estimated terminal differential pressure control, the set value of the return differential pressure is changed to a small value within a range that does not cause an insufficient flow rate of the air conditioner during partial load. A technique for increasing the effect of reducing pump power by control is disclosed (for example, see FIG. 1 of Patent Document 1).

FIG. 19 shows an example of a conventional heat medium piping system provided with such an air conditioner.
The heat medium piping system shown in FIG. 19 includes a heat source device 1 such as a refrigerator or a boiler, an outgoing main pipe 2 connected to the outlet side of the heat source device 1 and supplied with a heat medium such as cold water or hot water, A plurality of forward pipes 3 branched from the main pipe 2, an air conditioner 4 whose inlet side is connected to each forward pipe 3 and arranged in parallel to each other, a return pipe 5 connected to the outlet side of each air conditioner 4, and each return The return main pipe 6 connected to the inlet side of the heat source unit 1 and the outgoing main pipe 2 side are connected upstream so that the pipes 5 are joined together, and the heat medium flow direction upstream of the air conditioner 4 on the most heat source unit 1 side. It is connected to the return main pipe 2 on the side, and on the return main pipe 6 side, a bypass pipe 7 connected to the return main pipe 6 on the most downstream side in the heat medium flow direction from the air conditioner 4 on the most heat source unit 1 side is provided.

The bypass pipe 7 connects the first forward header 17 provided on the forward main pipe 2 and the return header 18 provided on the return main pipe 6.
A heat source pump (primary pump) 8 is connected to the return main pipe 6 on the heat source unit 1 side of the return header 18 provided at a position where the bypass pipe 7 is connected to the return main pipe 6. A secondary pump 9 capable of inverter-controlling the rotational speed of the motor that drives the impeller on the heat medium flow direction side from the header 17 is connected, and a second forward header 19 provided on the discharge side of the secondary pump 9 is provided. Yes.
Each return pipe 5 is provided with a two-way valve 10.
The air-conditioning target area 11 where air conditioning is performed by each air conditioner 4 is based on a temperature sensor 12 that measures the air temperature in the control target area, and a deviation between a measurement signal from the temperature sensor 12 and a set temperature that is set. A temperature control device (TIC) 13 that adjusts the opening of the two-way valve 10 with the calculated output is installed.

A differential pressure gauge 14 that measures the differential pressure between the second header 19 of the forward main pipe 2 and the return main pipe 6 and outputs the differential pressure is provided. The measured value of the differential pressure gauge 14 is output to the secondary pump controller 16 including a pressure indicating controller function.
First, the secondary pump controller 16 receives the load flow rate measurement value from the flow meter 15 provided in the return main pipe 6, and calculates and determines the set value of the differential pressure using a preset equation. Next, the secondary pump 9 that has been PID-calculated based on the deviation between the measured value of the differential pressure between the headers measured by the differential pressure gauge 14 and the calculation-determined differential pressure setting value in the current flow meter measurement value. An output signal corresponding to the inverter frequency is output.

In the heat medium piping system shown in FIG. 19, the heat medium cooled or heated and sent from the heat source device 1 is sent to the forward main pipe 2 by the heat source pump 8, and a part of the heat medium passes through the bypass pipe 7. It flows into the return main pipe 6.
Further, the remaining heat medium is further fed to the forward main pipe 2 by the secondary pump 9, introduced into the air conditioner 4 from the forward pipe 3, consumes cold or hot heat, passes through the return pipe 5 to the return main pipe 6. It flows in and returns to the heat source unit 1 together with the heat medium from the bypass pipe 7. At this time, the temperature control device 13 causes the two-way valve 10 so that the heat medium passing through the air conditioner 4 has a predetermined air temperature in the air conditioning target area 11 by the air supplied to the air conditioning target area 11 through the air conditioner 4. Control the flow rate. The bypass pipe 7 does not consume the heat or heat of the heat medium and returns to the heat source unit 1 in the secondary piping system on the air conditioner 4 side of the first forward header 17 and the return header 18 in a plurality of two directions. Although the flow rate of the heat medium greatly fluctuates with the opening and closing of the valve 10, the heat medium flow rate of the heat source device 1 that should be secured at least is determined in order to prevent the heat source device 1 from malfunctioning, and the flow rate is secured. Because.

In the heat medium piping system shown in FIG. 19, an increase in piping resistance due to adjustment of the opening degree of the two-way valve 10 is alleviated, and a reduction in pump power is desired.
However, in the heat medium piping system shown in FIG. 19, even when the load for each air conditioner 4 is unevenly distributed, the set value of the return differential pressure must be set with a margin so that the flow rate of the air conditioner 4 is not insufficient. I do not get. Therefore, there is a problem that the throttle resistance of the two-way valve 10 is generated in the piping system by an amount corresponding to the set value being increased, and the pump power is increased.
On the other hand, if the set value of the return differential pressure is made too small as necessary, the flow rate of the air conditioner 4 will be insufficient. Therefore, how to determine the set value of the return differential pressure to maximize the pump power reduction effect There is a problem that is difficult.

Thus, for example, as shown in FIG. 20, a method has been proposed in which the pump power can be significantly reduced by completely eliminating the throttle resistance of the two-way valve 10 (see, for example, Patent Document 2). In FIG. 20, the same reference numerals as those in the heat medium piping system shown in FIG. 19 represent the same functions.
In the heat medium piping system shown in FIG. 20, in order to independently air-condition a plurality of air-conditioning target areas 11 in the distributed system including the outgoing pipe 3 and the return pipe 5 between the outgoing main pipe 2 and the return main pipe 6, An air conditioner pump 20 capable of inverter-controlling the rotational speed of a motor that drives the impeller from the upstream side toward the downstream side, an air conditioner 4, and a two-way valve 21 that can be fully opened and fully closed are sequentially connected to the pipe 22. I have.

  The movement of the air conditioner pump 20 and the two-way valve 21 that can be fully closed and fully opened is controlled by the control device 23. In the air conditioner pump 20, the rotational speed of the impeller is controlled by the control device 23 based on a deviation between a measured value and a set value by the temperature sensor 12 in the air conditioning target area 11 targeted by the air conditioner 4. The two-way valve 21 that can be fully closed and fully opened is controlled by the control device 23 so that it is closed when the air conditioner pump 20 is started up and fully opened after the rotation speed of the air conditioner pump 20 reaches a predetermined rotation speed. Yes. The two-way valve 21 that can be fully closed and fully opened is preferably a ball valve having the same diameter as the pipe 22 and having a small flow resistance in the pipe 22, particularly a two-position control type full-bore electric ball valve. is there. Further, a two-position control type electric butterfly valve having the same diameter as the pipe 22 is suitable.

In the heat medium piping system shown in FIG. 20, in addition to the two-way valve 21, an air conditioner pump 20 is installed for each air conditioner 4, the two-way valve 21 is fully closed when the air conditioner 4 is stopped, and the air conditioner 4 is in operation. The two-way valve 21 is fully opened, and the flow rate is adjusted by the air conditioner pump 20.
And if the secondary pump 9 and the air conditioner pump 20 share the lifting head and each dispersion system has a little load, the air conditioner pump 20 is operated.
In any distributed air conditioner pump 20, the secondary pump 9 measures the flowmeter 15 on the secondary curve with the rated flow rate and the rated head as maximum values so that the suction does not become a negative pressure from the atmospheric pressure. The pressure control device 16 calculates the head pressure set value by moving in accordance with the flow rate, measures the differential pressure between the forward main pipe 2 and the return main pipe 6 (forward differential pressure) with the differential pressure gauge 14 and sets it to the set value at that flow rate. It is controlled by.
When the two-way valve 21 has the same inner diameter as that of the relationship when fully opened and there is no pressure loss and the load of its own dispersion system disappears, the two-way valve 21 is closed to prevent backflow due to the pressure of the adjacent air conditioner pump 20.

Japanese Patent No. 3917835 JP 2010-112699 A JP 60-226650 A

In the heat medium piping system shown in FIG. 20, if the device capacity of the air conditioner pump 20 is smaller than the device capacity of the secondary pump 9, the secondary pump 9 and the air conditioner pump 20 share the head. In some cases, the power consumption of the system as a whole increases in consideration of the pump efficiency (generally, the efficiency of pump equipment depends on the volume ratio of the parts that do not contribute to the work of the pump casing and impeller, and the generated magnetic field Because the motor efficiency is based on the volume ratio of the part that changes to heat without affecting work, the larger the pump capacity, the greater the tendency.)
In this case, in order to reduce the power consumption of the entire system, the set value of the return differential pressure controlled by the secondary pump 9 should be as large as possible, and the work rate of the secondary pump 9 should be increased.
However, in the heat medium piping system shown in FIG. 20, information about the air conditioner is necessary and difficult to control in order to prevent the back pressure on the air conditioner pump 20 from increasing and the flow rate of the air conditioner from becoming uncontrollable.

In Patent Document 3, a dispersion pump is provided in each dispersion system without using a secondary pump, and the temperature measurement value of the control target region is input to the temperature indicator controller, and the calculation result of the temperature indicator controller is A heat source system that outputs a control signal to each of the dispersion pump and the on-off valve and controls the dispersion pump accordingly by inputting to another output control device or dividing into two kinds of signals by the control signal converter. There is disclosure.
The on-off valve is a ball valve or butterfly valve that is likely to have the same inner diameter as the branch pipe when fully opened, and if there is no pressure loss on its own dispersion system, it will be closed to prevent backflow due to the adjacent dispersion pump pressure It is configured. According to Patent Document 3, the on-off valve is not a flow rate control like a two-way valve.
However, in Patent Document 3, since there is no technique for measuring the differential pressure between the heat medium forward main pipe and the heat medium return main pipe, and there is no secondary pump controlled by the technique, there is a problem in the heat medium piping system shown in FIG. Cannot be resolved.

  The present invention has been made in order to solve such a conventional problem, and an object of the present invention is to control the rotational speed of the air conditioner pump and the opening of the two-way valve provided in each dispersion system on the load side. By sending the output signal obtained by calculating the air temperature measurement signal in the area to each operating device (pump inverter and two-way valve) as an output-adjusted signal, control of the secondary pump on the central side and the air-conditioner piping system An object of the present invention is to provide a heat medium piping system capable of realizing energy-saving conveyance of a heat medium from a heat source by simple control separating local control.

  The invention according to claim 1 is an air conditioner pump in which the rotation speed of a motor that drives an impeller is inverter-controllable, an air conditioner having a coil that flows a heat medium for heat exchange with air to be sent to a control target area, A two-way valve with adjustable opening is provided in the forward pipe and the return pipe in order, and an air conditioner piping system arranged independently for each of a plurality of air conditioning target areas, and the air conditioner pump of the air conditioning machine piping system A temperature control device for controlling the rotational speed and the opening degree of the two-way valve, a heat source device for supplying a heat medium adjusted in temperature to each air conditioner piping system, and each air conditioning piping system A forward main pipe connected to each air conditioner pump inlet side forward pipe and the outlet side of the heat source device via a first forward header, each two-way valve outlet side return pipe of each air conditioner piping system, and the heat source device Return pipe connected to the entrance side of the car via a header A primary pump that is located on the inlet side of the heat source device of the return main pipe and conveys the heat medium with a head for a pressure loss from the return header to the first forward header, and the heat to each air conditioner piping system A secondary pump capable of inverter-controlling the rotational speed of a motor that drives an impeller disposed downstream of the first forward header of the forward main pipe that conveys the medium, and a middle of the forward main pipe on the discharge side of the secondary pump A second forward header connected to the first header, a header bypass pipe connecting the first forward header and the return header, a differential pressure gauge for measuring a differential pressure between the second forward header and the return header, and the differential pressure gauge A pressure control device that controls an inverter of the secondary pump based on a measured value; and a flow meter that is installed upstream of the return header of the return pipe. Temperature sensor for measuring the air temperature in the control target area for each air conditioning target area, and the primary control output as a result of PI calculation based on the deviation between the measured value from the temperature sensor and the air temperature set value in the control target area From the temperature indicating controller, a first output adjusting device that adjusts and outputs a control output to the inverter of the air conditioning pump based on a primary control output from the temperature indicating controller, and the temperature indicating controller A second output adjusting device that adjusts and outputs the opening control output of the two-way valve based on the primary control output, and for the adjustment assignment between the first output adjusting device and the second output adjusting device. By providing the difference, the frequency adjustment of the inverter of the air conditioner pump is changed before the adjustment of the opening degree of the two-way valve when the primary control output fluctuates, and the pressure control device A load flow measurement value measured with a meter is inputted, a set value of differential pressure is calculated by a relational expression between a load flow rate and a set differential pressure given in advance, and calculated with a differential pressure measurement value measured with the differential pressure meter The inverter of the secondary pump is controlled by a pressure control output calculated based on a deviation from the set value of the differential pressure.

According to a second aspect of the present invention, in the heat medium piping system according to the first aspect, the secondary pump is an air conditioner having the lowest head among the air conditioner pumps with all the two-way valves fully opened. The rated flow rate Q0 that can process the total heat load of all the air conditioners in a state where the air conditioner pump inverter is controlled so that the head is at 0 kPa and a predetermined flow rate flows. It can be transported at a rated head P0 that can cover the pressure loss of the forward main pipe, the return main pipe and the air conditioner piping system up to the connection point of the forward pipe return pipe of the air conditioner piping system including the air conditioner pump having the lowest lift. It has the ability.
According to a third aspect of the present invention, in the heat medium piping system according to the first or second aspect, the pressure control device calculates the return differential pressure P0 at the rated flow rate Q0 from the rated head P0 at the rated flow rate Q0 of the secondary pump. The reference value of the relational expression between the load flow rate and the set differential pressure is used, and the set value of the differential pressure is changed in proportion to the square of the measured load flow rate value of the flow meter.

The invention according to claim 4 is the heat medium piping system according to any one of claims 1 to 3, wherein each air conditioner pump has a rating of each air conditioner even if the lift of the secondary pump is zero. In order to secure the flow rate, the flow rate is allowed to flow at a rated head sufficient to cover the pressure loss from the first forward header to the return header.
According to a fifth aspect of the present invention, in the heat medium piping system according to any one of the first to fourth aspects, the temperature control device in the control target region is configured to control the two-way valve during control by adjusting the rotation speed of the air conditioner pump. Fully open and when the air conditioner pump rotation speed reaches the lower limit, the air conditioner pump rotation speed adjustment and the two-way valve opening adjustment are controlled by adjusting the two-way valve opening degree adjustment. It is characterized by performing.

The invention according to claim 6 is the heat medium piping system according to any one of claims 1 to 5, wherein the two-way valve is a full-bore electric ball valve or butterfly valve having the same inner diameter as the return pipe when fully opened. Compared to the above, there is almost no increase in pressure loss.
The invention according to claim 7 is the heat medium piping system according to any one of claims 1 to 6, wherein the first output adjustment device and the second output adjustment device are ratio bias setting devices. .

The present invention provides an air conditioner pump and a two-way valve as a dispersion pump in each load-side temperature control piping system as an air conditioning water transfer system for an air conditioner, and the rotation speed of the air conditioner pump and the opening degree of the two-way valve are By controlling each of the signals obtained by calculating the measurement signal of the air temperature in the control target area as two ratio biases, energy-saving conveyance is realized by simple control that separates the control of the central secondary pump and the local control.
For this reason, the set value of the return differential pressure can be lowered as desired without causing an insufficient flow rate of the air conditioner, the throttle resistance of the two-way valve is reduced, and the pump power including the air conditioner pump is reduced. be able to.

The set value of the return differential pressure can be easily determined such as a curve proportional to the square of the load flow rate based on the value at the rated flow rate.
In addition, the set value of the return pressure of the secondary pump is set as a proportional curve to the square of the load flow rate based on the value at the rated flow rate, but the value at the rated flow rate is within the range where the opening of the two-way valve is not adjusted. By making it as large as possible, the work rate of the secondary pump increases and the power consumption of the entire system can be reduced.
Further, since the control around the secondary pump and the air conditioners can be configured separately, the control can be easily configured.

It is explanatory drawing which shows the heat carrier piping system which concerns on one Embodiment of this invention. It is explanatory drawing which shows the temperature control apparatus of the control object area | region of FIG. It is explanatory drawing which shows the driving | running state A which is a rated condition in the heat carrier piping system of FIG. Explanatory drawing which shows the state which the load of the air conditioners 41-44 decreased equally from the operating state A which is a rated condition shown in FIG. 3 (the load flow rate decreased from 100 L / min to 50 L / min) and changed to the operating state B It is. It is a graph which shows the driving | running state of the secondary pump in the driving | running state A which is a rated condition shown in FIG. It is a graph which shows the driving | running state of the inverter and the two-way valve of the air conditioner pump of the air conditioners 41-44 in the driving | running state A which is a rated condition shown in FIG. It is a graph which shows the driving | running state of the air conditioner pump of the air conditioners 41-44 in the driving | running state A which is a rated condition shown in FIG. It is a graph which shows the driving | running state of the inverter and the two-way valve of the air conditioner pump of the air conditioners 41-44 in the middle process from the driving | running state A which is a rated condition shown in FIG. 3 to the driving | running state B shown in FIG. FIG. 5 is a graph showing an operation state of the secondary pump in an intermediate process from an operation state A which is a rated condition shown in FIG. 3 to an operation state B shown in FIG. 4. It is a graph which shows the driving | running state of the inverter and the two-way valve of the air conditioner pump of the air conditioners 41-44 in the middle process from the driving | running state A which is a rated condition shown in FIG. 3 to the driving | running state B shown in FIG. It is a graph which shows the driving | running state of the air conditioner pumps of the air conditioners 41-44 in the middle process from the driving | running state A which is a rated condition shown in FIG. 3 to the driving | running state B shown in FIG. It is explanatory drawing which shows the state which the load of the air conditioner 41 decreased equally from the driving | running state A which is a rated condition shown in FIG. 3 (load flow volume decreased from 100L / min to 20L / min), and changed into the driving | running state C. . It is a graph which shows the driving | running state of the inverter of the air conditioner pump of the air conditioning machine 41 and the two-way valve in the middle process from the driving | running state A which is a rated condition shown in FIG. 3 to the driving | running state C shown in FIG. It is a graph which shows the driving | running state of the secondary pump in the middle process from the driving | running state A which is a rated condition shown in FIG. 3 to the driving | running state C shown in FIG. It is a graph which shows the driving | running state of the inverter of the air conditioner pump of the air conditioning machine 41 and the two-way valve in the middle process from the driving | running state A which is a rated condition shown in FIG. 3 to the driving | running state C shown in FIG. It is a graph which shows the driving | running state of the air conditioner pump of the air conditioning machine 41 in the middle process from the driving | running state A which is a rated condition shown in FIG. 3 to the driving | running state C shown in FIG. It is a graph which shows the driving | running state of the inverter and the two-way valve of the air conditioner pump of the air conditioning machines 42-44 in the middle process from the driving | running state A which is the rated conditions shown in FIG. 3 to the driving | running state C shown in FIG. It is a graph which shows the driving | running state of the air conditioner pump of the air conditioners 42-44 in the middle process from the driving | running state A which is a rated condition shown in FIG. 3 to the driving | running state C shown in FIG. It is explanatory drawing which shows the conventional heat carrier piping system. It is explanatory drawing which shows another conventional heat carrier piping system.

Hereinafter, the present invention will be described based on embodiments shown in the drawings.
1-18 is explanatory drawing which shows the heat carrier piping system which concerns on one Embodiment of this invention. In addition, the structure of the same symbol as FIG. 19, FIG. 20 represents the same function.
As in the heat medium piping system shown in FIG. 20, the heat medium piping system according to the present embodiment is a primary pump 8 that circulates cold / hot water on the heat source unit 1 side, an inverter that circulates cold / hot water to the air conditioner 4 side, and the like. A temperature control piping system X, which is an air conditioner piping system for independently air-conditioning a plurality of air-conditioning target regions 11, and a heat pump. And a medium main transport loop Y.

The temperature control piping system X which is an air conditioner piping system includes an air conditioner pump 20 which is a distributed pump capable of controlling the rotation speed by an inverter or the like in the forward pipe 3 from the upstream side to the downstream side, and an air conditioner (blower, eliminator, The air handling unit or fan coil unit including a humidifier, a heating coil, a cooling coil, a filter, a drain pan, and the like) 4 and a two-way valve 10 whose opening degree can be adjusted to the return pipe 5 are arranged in this order. The pipe 22 is a return pipe return pipe, and is connected between the forward main pipe 2 and the return main pipe 6 of the heat medium main transport loop Y.
The air-conditioning target region 11 that is air-conditioned by each temperature control piping system X includes a control target region temperature control device Z that controls the rotation speed of the inverter 20a of the air conditioner pump 20 and the opening degree of the two-way valve 10. Yes.

  As shown in FIGS. 1 and 2, the temperature control device Z for the control target area includes a temperature sensor 12 that measures the air temperature in the control target area for each of the plurality of air conditioning target areas 11, and a measured value from the temperature sensor 12. Based on the temperature control device 30 that is a temperature indicating controller that outputs a primary control output as a result of PI or PID calculation based on the deviation from the air temperature set value in the control target region, and the primary control output from the temperature control device 30 A first output adjusting device 31 that adjusts the control output to the inverter 20a of the air conditioning pump 20 and a second output adjustment that adjusts the opening control output of the two-way valve 10 based on the primary control output from the temperature control device 30. The first output adjustment device 31 and the second output adjustment device 32 that are provided with the device 32 and have received the primary control output, adjust the primary control output with a different assignment, and output the difference. By providing, so that upon variation of the primary control output, changing the previously frequency adjustment of the inverter 20a of the air conditioner pump 20 than the opening degree adjustment of the two-way valve 10.

  The heat medium main transfer loop Y includes a heat source device 1 that supplies a temperature-controlled heat medium to each temperature control piping system X, an air conditioner pump 20 inlet-side forward pipe 3 of each temperature control piping system X, and a heat source device 1. The return main pipe 2 connected to the outlet side via the first forward header 17, the return side return pipe 5 of each two-way valve 10 of each temperature control piping system X, and the inlet side of the heat source unit 1 via the return header 18 A return main pipe 6 connected to each other, a primary pump 8 which is located on the inlet side of the heat source unit 1 of the return main pipe 6 and conveys the heat medium by a head of pressure loss from the return header 18 to the first forward header 17, and a temperature control pipe A secondary pump 9 capable of inverter-controlling the rotational speed of a motor that drives an impeller disposed downstream of the first forward header 17 of the forward main pipe 2 that conveys the heat medium to the system X; A second forward header 19 connected in the middle of the main pipe 2 going to the side, Measures the differential pressure between the header bypass pipe 7 connecting the forward header 17 and the return header 18, the flow meter 15 provided upstream of the return header 18 of the return main pipe 6, and the second forward header 19 and the return header 18. And a pressure control device 16 that takes in the measured values of the differential pressure gauge 14 and the flow meter 15 and controls the inverter 9 a of the secondary pump 9.

In addition, as the heat source unit 1, a cold heat source device including a refrigerator and a cooling tower, a hot heat source device including a steam boiler, a steam / water heat exchanger, a cold / hot water generator, and the like are used.
A heat source pump 8 that is a primary pump is connected to the return main pipe 6 on the side of the heat source unit 1 with respect to the return header 18 provided at a position where the bypass pipe 7 is connected to the return main pipe 6. A secondary pump 9 capable of inverter-controlling the rotational speed of the motor driving the impeller is connected to the forward main pipe 2 on the medium flow direction side, and a second forward header 19 is provided on the discharge side of the secondary pump 9. .
In the pressure control device 16, the measured value of the load flow rate measured by the flow meter 15 is input, the set value of the differential pressure is calculated by the relational expression between the load flow rate given in advance and the set differential pressure, and measured by the differential pressure meter 14. Based on the difference between the measured differential pressure value and the calculated set value of the differential pressure, for example, the inverter 9a of the secondary pump 9 is controlled by the pressure control output calculated by PI or PID.

In the present embodiment, the piping resistance from the return header 18 to the first forward header 17 via the heat source unit 1 (also referred to as the heat source side and the primary side) is substantially equal to the head of the primary pump 8, and from the first forward header 17. The piping resistance from each air conditioner 4 to the return header 18 (secondary side) is approximately equal to the lift of the secondary pump 9 plus the lift of the air conditioner pump 20 corresponding to each air conditioner 4. . That is, the work amount for circulating cold / hot water to the secondary side is shared by the secondary pump 9 and the plurality of air conditioner pumps 20. At this time, the ratio of the work amount (stroke) of the secondary pump 9 having high operation efficiency as a single unit with respect to the air conditioner pump 20 is set as large as possible.
The secondary pump 9 takes into account the characteristic that the pipe resistance including the coil and the valve is proportional to the square of the flow rate, and the return differential pressure measured by the differential pressure gauge 14 (≈ lift of the secondary pump 9) 4 is set and controlled by a relational expression between the load flow rate given in advance to the pressure control device 16 and the set differential pressure so as to be a value proportional to the square of the load flow rate, which is the sum of the four flow rates.

The flow rate adjustment according to the heat load of each air conditioner 4 is performed by the air conditioner pump 20 and the two-way valve 10 corresponding to each, but basically in two directions (when the load tendency of each air conditioner 4 is equal). The rotation speed of the inverter 20a of the air conditioner pump 20 is adjusted according to the heat load while keeping the valve 10 fully open.
When the load tendency of each air conditioner 4 varies, the work load by the secondary pump 9 is relatively small in the system having a higher load than the average of the total loads (the indentation pressure by the secondary pump 9). Therefore, the rotational speed of the inverter 20a of the air conditioner pump 20 increases in order to secure a flow rate corresponding to the heat load. On the other hand, in the system having a lower load than the average of the total load, the work amount by the secondary pump 9 becomes relatively large (because the pushing pressure by the secondary pump 9 becomes large), so that the inverter 20a of the air conditioner pump 20 When the rotational speed decreases and further reaches the lower limit rotational speed (lower limit frequency), the opening of the two-way valve 10 is throttled and adjusted to a flow rate according to the thermal load.

The capacity of the secondary pump 9 controls the inverter 20a of the air conditioner pump 20 with respect to the air conditioner pump 20 having the lowest head among the air conditioner pumps 20 with all the two-way valves 10 fully opened. In the state where the head is 0 kPa and the rated flow rate of the air conditioner pump 20 flows, the rated flow rate Q0 that can process the total amount of heat of the rated heat loads of all the air conditioners 4 is the air conditioning with the lowest lift. It has the ability to convey at the rated head P0 that can cover the pressure loss of the forward main pipe 2, the return main pipe 6 and the temperature control pipe 22 up to the connection point of the forward pipe return pipe of the temperature control piping system X including the mechanical pump 20. . If the lift of the secondary pump 9 is larger than P0, the back pressure from the secondary pump 9 to the air conditioner pump 20 becomes large, so that the control by the air conditioner pump 20 becomes impossible and the flow rate becomes excessive. At this time, the throttle resistance of the two-way valve 10 is generated to reduce the flow rate, the required power of the pump is increased, and the power consumption is increased. On the other hand, if the head of the secondary pump 9 is smaller than P ₀ , the work amount of the air conditioner pump 20 is increased, and the power consumption of the entire system considering the device efficiency is increased.

The secondary pump 9 performs inverter control so that the return differential pressure becomes a set value. Since the pressure control device 16 has the rated head P0 at the rated flow rate Q0 of the secondary pump 9, the return differential pressure P0 at the rated flow rate Q0 is used as a reference point for the relational expression between the load flow rate and the set differential pressure, The set value is changed in proportion to the square of the measured load flow rate value measured by the flow meter 15.
The capacity of each air conditioner pump 20 is such that the pressure loss from the first forward header 17 to the return header 18 so that the rated flow rate of each air conditioner 4 can be secured even if the head of the secondary pump 9 is zero. It has the ability to allow the rated flow to flow with a rated head that only covers Since the secondary pump 9 determines the return differential pressure based on the load flow rate that can be regarded as the average of the total load, there are many systems that have extremely small heat loads, especially when the heat load varies among the air conditioners 4. When there are a few systems with the rated heat load, the work of the secondary pump 9 becomes extremely small for the system with the rated heat load, and the work of the air conditioner pump 20 must be increased accordingly.

Next, a control method of the air conditioner pump 20 and the two-way valve 10 in the present embodiment will be described.
As with a general system, the air conditioner pump 20 and the two-way valve 10 adjust the amount of cold / hot water so as to keep the air temperature in the control target area constant, thereby processing the heat load. In many cases, the air temperature in the control target region is the supply air temperature when the air conditioner 4 has a variable amount of air, and the indoor air temperature of the representative room when the air conditioner 4 has a constant amount of air.
The air temperature in the control target area is controlled by adjusting the rotation speed of the inverter 20a of the air conditioner pump 20 and adjusting the opening of the two-way valve 10, but by adjusting the opening of the two-way valve 10, the inverter of the air conditioner pump 20 is controlled. Priority is given to the rotation speed adjustment of 20a. That is, when the two-way valve 10 is fully opened at the time of control by adjusting the rotation speed of the inverter 20a of the air conditioner pump 20, the opening degree adjustment of the two-way valve 10 is performed when the lower limit value of the rotation speed of the air conditioner pump 20 inverter 20a is reached. To be controlled by.

An example of a specific control method will be described based on FIG. FIG. 2 shows the cooling control operation.
The air temperature T in the control target area, which is a controlled variable, is input to the temperature control device 30, and PI or PID is calculated based on the deviation between the air temperature T in the control target area and its set value Tsp, and the control output X (0 to 0). 100%). The control output X (0 to 100%) from the temperature control device 30 is supplied to the first output adjusting device 31 such as a ratio bias setting device provided in the inverter 20a and the two-way valve 10 of the air conditioner pump 20, respectively. Input to the two-output adjusting device 32 and assign a value of the control output X of a certain reference value (for example, 50%) to 100% to 0 to 100% as the control output XINV to the inverter 20a of the air conditioner pump 20 The value of the control output X from 0% to a certain reference value (for example, 50%) is assigned to 0 to 100% as the control output Xvalve to the two-way valve 10 and output.

  By doing in this way, for example, when the heat load increases during cooling, the amount of cold water required for the heat load decreases, so the air temperature in the control target region increases. At this time, since the control output X is increased by the PID calculation of the temperature control device 30, when the frequency of the inverter 20a of the air conditioner pump 20 is the lower limit, the opening degree of the two-way valve 10 is increased, or the two-way valve 10 When fully opened, the frequency of the inverter 20a of the air conditioner pump 20 increases, so that the amount of cold water increases, so that the heat load can be processed.

Note that the proportional band in the temperature control device 30 is a parameter that is adjusted locally in accordance with the response of the actual system. Further, the value of 50% given as an example of the reference value means that the proportional band in the temperature control device 30 is divided into the inverter 20a and the two-way valve 10 with this value as a boundary (for example, this 50% When the value is increased, the response of the control output X _INV for the inverter 20a becomes faster and the response of the control output X _valvs for the two-way valve 10 becomes slower with respect to the change of the control output X). This parameter is adjusted locally according to
Further, the proportional band in the temperature control device 30, the first output control device 31, and the second output device 32 is a parameter that is adjusted on site in accordance with the response of the actual system.

Next, the operation of the heat medium piping system according to this embodiment will be described.
From the operating state A, which is the rated condition shown in FIG. 3, the load of the air conditioners 41 to 44 is evenly reduced (the load flow rate is reduced from 100 L / min to 50 L / min), and changes to the operating state B shown in FIG. The control operation of each control device will be described.
Each control device controls an individual control target (the air conditioner pump 20 and the two-way valve 10 each have an air temperature T in the control target area, and the secondary pump 9 has a return differential pressure). Thus, the balance is finally achieved in the driving state B.

In the operating state A, which is the rated condition shown in FIG. 3, the reference pressure (expansion tank connection position) is 100 kPa. Further, as shown in FIG. 5, the operation state of the secondary pump 9 is as follows: resistance curve given to the pressure control device 16 = set pressure (Psp = aQ2) (where a is a coefficient and Q is a flow rate). , The intersection with the rated pump characteristic curve (inverter 9a set frequency of the secondary pump 9 is 50 Hz), the flow rate of 400 L / min, the lift of 200 kPa, the motor that drives the impeller of the secondary pump 9 is the inverter frequency of 50 Hz Rotate with supply power to secure.
Here, the control of the inverter 9 a of the secondary pump 9 is controlled by the pressure controller 16 as follows. First, enter the load flow rate Q measured by the flow meter 15, the arithmetic expression is set in advance (P _sp = aQ ^2), calculates the set value P _sp differential pressure (shuttle differential pressure). Here, a is a value set in advance from the flow rate at the rated time and the head, and in this example, a = (200/400 ² ). Next, the differential pressure between the headers 18 and 19 (return differential pressure) measured by the differential pressure gauge 14 is input, and the differential pressure between the headers 18 and 19 (return differential pressure) is calculated by the equation (P _sp = aQ ² ). This is performed based on the value calculated by PID so that the calculated set value _Psp is obtained.

As shown in FIG. 3, the pipe resistance of the forward main pipe 2 in the common portion is 50 kPa, so that the joint between the forward pipe 3 and the forward main pipe 2 of the piping system 22 connected to the air conditioners 41 to 44 is 250 kPa, respectively. Pressure is applied.
In the operating condition A, which is a rated condition, the pressure of the secondary pump 9, that is, the lift, is naturally set large in order to reduce the transport power consumption of the entire system, and the lift of the small capacity air conditioner pump 20 is set to 0, which is extremely small. Should be. Therefore, the head of the air conditioner pump 20 connected to the air conditioners 41 to 44 is 0 kPa, the coil resistance of each of the air conditioners 41 to 44 is 80 kPa, and the resistance when the two-way valve is fully opened is 20 kPa. Therefore, the pressure on the inlet side of the air conditioners 41 to 44 is 250 kPa, the flow rate is 100 L / min, the pressure on the outlet side of the air conditioners 41 to 44 is 170 kPa, and the pressure at the joint with the return main pipe 6 is 150 kPa.

As shown in FIG. 6, the operating state of the inverter 20 a of the air conditioner pump 20 and the two-way valve 10 (common to the air conditioners 41 to 44) is set in the temperature control device 30 as the set value SP of the air temperature in the control target region. The measured output PV is 70% control output.
Based on this, the inverter 20a of the air conditioner pump 20 has an inverter control output of 46% obtained by the first output adjustment device 31 (when 0 to 100% of the inverter control output is assigned to 0 to 50 Hz of the frequency of the inverter 20a). The frequency of the impeller is controlled by 23 Hz, and so on. FIG. 7 shows the operating state of the air conditioner pump 20. Although the head is 0 kPa, it is naturally transported at a flow rate of 100 L / min to be transported.
Further, as shown in FIG. 6, the two-way valve 10 outputs the two-way valve control output 100% reassigned by the second output adjusting device 32, and the opening degree of the two-way valve 10 is controlled to be fully opened. .
Since the piping resistance of the return main pipe 6 is 50 kPa, the pressure in the return header 18 is 100 kPa, which matches the reference pressure (expansion tank connection position).

Next, an intermediate process from the operation state A to the operation state B will be described.
As shown in FIG. 8, when the load on the air conditioners 41 to 44 decreases, the measured value PV of the air temperature in the control target area decreases in the direction of the arrow, and the control output becomes 70% to 40%. At this time, the control output to each temperature control piping system similarly decreases, the output reassigned via the first output adjustment device 31 is 0%, that is, the frequency of the inverter 20a of the air conditioner pump 20 is the lowest frequency. (For example, 5 Hz), the output reassigned via the second output adjustment device 32 outputs 80% as the opening adjustment signal of the two-way valve.
Next, since the entire load flow rate is reduced by a factor of 2 from 400 L / min to 200 L / min, as shown in FIG. 9, the secondary pump 9 has a pressure proportional to the square of the load flow rate, that is, 4 of 200 kPa. The resistance curve given in advance to the pressure control device 16 = set pressure (Psp = aQ2) (where a is a coefficient and Q is a flow rate) is changed so as to be 50 kPa which is a fraction, and as a result, the inverter Reduce the frequency of 9a from 50 Hz to 25 Hz.

Next, since the head of the secondary pump 9 decreases, the pushing pressure in each air conditioner system decreases, and the flow rate decreases as a whole. As a result, in each of the air conditioners 41 to 44, the flow rate necessary for processing the load does not flow, and the measured value PV of the air temperature in the control target area increases as shown in FIG. Then, the frequency of the inverter 20a of the air conditioner pump 20 is 11.5 Hz, the open / close control signal of the two-way valve 10 is 100%, and it is fully opened. FIG. 11 shows the operating state of each air conditioner pump 20, and the flow rate is reduced from 100 L / min to 50 L / min by reducing the frequency of the inverter 20a from 23 Hz to 11.5 Hz.
Through the above process, the operation state B shown in FIG. 4 (the state in which the load flow rates of the air conditioners 41 to 44 are uniformly reduced to 50 L / min) is obtained.
As for the above control operation, the control amount is suddenly changed to explain the operation of the control device in an easy-to-understand manner. However, since the actual change is gradual, the control amount changes abruptly in this way. There is nothing. Further, the difference (offset) between the installation value SP and the measurement value PV in the operation state B is removed by the integration operation.

Next, from the operating state A which is the rated condition shown in FIG. 3, as the load of the air conditioner 41, for example, only one of the four units is reduced (load flow rate is reduced from 100 L / min to 20 L / min), The control operation of each control device when it changes to the operation state C where the load shown in FIG. 12 is unevenly distributed will be described.
Each control device controls an individual control object (the air conditioner pump 20 and the two-way valve 10 have the air temperature T in the respective control object area, and the secondary pump 9 has the return differential pressure). Thus, the balance is finally achieved in the driving state C.

The operation state of the secondary pump 9, the operation state of the inverter 20a and the two-way valve 10 of the air conditioner pump 20, and the operation state of the air conditioner pump 20 are as shown in FIGS.
Next, an intermediate process from the operation state A shown in FIG. 3 to the operation state C shown in FIG. 12 will be described.
First, when the load of the air conditioner 41 decreases, the measured value PV of the air temperature in the control target region decreases. At this time, when the control output from the temperature indicating controller (TIC) 30 of the air conditioner 41 system decreases and the load on the air conditioner 41 decreases as shown in FIG. It decreases in the direction of the arrow, and the control output is changed from 70% to 15%. At this time, the control output to the air conditioner 41 system is similarly reduced, the output reassigned via the first output adjustment device 31 is 0%, that is, the frequency of the inverter 20a of the air conditioner pump 20 is the lowest frequency (for example, 5 Hz), and the output reassigned via the second output adjustment device 32 is reduced to 30% as the opening degree adjustment signal of the two-way valve 10.

Next, since the entire load flow rate is reduced from 400 L / min to 320 L / min at a rate of 0.8, as shown in FIG. 14, the secondary pump 9 has a pressure proportional to the square of the load flow rate, that is, 200 kPa. The resistance curve given in advance to the pressure control device 16 = set pressure (Psp = aQ2) (where a is a coefficient and Q is a flow rate) is changed to a result of 128 kPa, which is a ratio of 0.64. The frequency of the inverter 9a is reduced from 50 Hz to 40 Hz.
Next, since the head of the secondary pump 9 is reduced from 200 kPa to 128 kPa, the pushing pressure in each air conditioner system is lowered, and the flow rate is reduced as a whole. As a result, as shown in FIG. 15, in the air conditioner 41, the flow rate necessary for processing the load does not flow, and the measured value PV of the air temperature in the control target region increases, so the control output is 15% to 30%. The opening signal of the two-way valve 10 increases from 30% to 60% while the frequency of the inverter 20a of the air conditioner pump 20 remains at 5 Hz. FIG. 16 shows the operating state of the air conditioner pump 20 in the system of the air conditioner 41. The frequency of the inverter 20a is decreased from 23 Hz in the operating state A to 5 Hz in the operating state C, so that the flow rate is 100 L / min to 20 L. / Min.

Further, as shown in FIG. 17, in the air conditioners 42 to 44, the flow rate necessary for processing the load does not flow, and the measured value PV of the air temperature in the control target area rises. The frequency of the inverter 20a of the air conditioner pump 20 increases from 23 Hz to 32 Hz, and the opening signal of the two-way valve 10 remains 100%. FIG. 18 shows the operating state of the air conditioner pump 20 in the system of the air conditioners 42 to 44. The frequency of the inverter 20a is increased from 23 Hz in the operating state A to 32 Hz in the operating state C. The head is increasing.
Through the above process, the operation state C shown in FIG. 12 (the state in which the load flow rate of the air conditioner 41 is reduced to 20 L / min) is obtained.

Next, a trial calculation example of power in the heat medium piping system according to the present embodiment and the conventional heat medium piping system shown in FIGS. 19 and 20 will be described.
Trial calculation condition For example, when the flow rate of each air conditioner 41-44 becomes the following conditions,
Air conditioner 41: 100L / min
Air conditioner 42: 80L / min
Air conditioner 43: 60L / min
Air conditioner 44: 40L / min
(At this time, the flow rate of the common return pipe: 280 L / min)
Since the pipe resistance is proportional to the square of the flow rate, each pipe resistance is as follows. The air conditioners 4 in the conventional heat medium piping system shown in FIGS. 19 and 20 will be described as air conditioners 41 to 44 as in FIGS. 3, 4, and 12.

Air conditioner 41 circulation piping: 100 kPa [= 100 × (100/100) ² kPa]
Air conditioner 42 circulation piping: 64 kPa [= 100 × (80/100) ² kPa]
Air conditioner 43 circulation piping: 36 kPa [= 100 × (60/100) ² kPa]
Air conditioner 44 circulation piping: 16 kPa [= 100 × (40/100) ² kPa]
Common return piping: 49 kPa [= 100 × (280/400) ² kPa]
Table 1, Table 2, and Table 3 show the motive power of each system under the above conditions.

In Tables 1 to 3, pump water power (Pw [kW]) is power actually given to the fluid from the pump.
Pw = ρgQH / 1000 = ρg (Q ′ / 60000) (H ′ / 9.8) / 1000
= Q'H '/ 60000
ρ: Density [kg / m ³ ]
g: Gravity acceleration [m / s ² ]
Q: Pump flow rate [m ³ / s]
H: Pump head [m]
Q ': Pump flow rate [L / min]
H ': Pump head [kPa]
The pump shaft power (P [kW]) is power necessary to move the pump.
P = Pw / η
η: Pump efficiency

  Table 1 corresponds to the system of FIG. The return differential pressure (≈the head of the secondary pump 9) has a margin of 0 kPa, and is a value obtained by adding 25 kPa of the common return piping to 100 kPa of the circulation piping of the air conditioner 41 having the largest piping resistance. This is a case where the set value of the differential pressure (return differential pressure) can be ideally set. However, since the actual return differential pressure is set with a value allowing for a margin, the pump shaft power is larger than 1.158 kW. Become.

Table 2 corresponds to the system of FIG. The return differential pressure (≈the head of the secondary pump 9) is 25 kPa proportional to the square of the load flow rate with reference to the resistance of the common circulation pipe at the rated time of 100 kPa, and thereafter the pressure is increased by each air conditioner pump 20. Assuming that the pump water power is 0.528 kW and the pump efficiency is as shown in the above table, the pump shaft power is 1.129 kW.
Compared to the system of FIG.

Table 3 corresponds to the system of FIG. The return differential pressure (≈the lift of the secondary pump) is 50 kPa proportional to the square of the load flow rate with reference to the maximum resistance of 200 kPa at the rated time, and thereafter, the air pressure is increased by each air conditioner pump 20 or the opening of the two-way valve 10 Adjustments are being made. Assuming that the pump water power is 0.562 kW and the pump efficiency is as shown in the above table, the pump shaft power is 1.044 kW. However, when the head of the air conditioner pump 20 was 0 kPa, it was assumed that the pump had the lowest frequency, and a constant value of 0.010 kW (actual value obtained by experiment) was given to the pump shaft power.
Compared to the system of FIG.

DESCRIPTION OF SYMBOLS 1 Heat source machine 2 Outbound main pipe 4 Air conditioner 6 Return main pipe 7 Bypass pipe 8 Primary pump 9 Secondary pump 9a Inverter 10 Two-way valve 11 Air-conditioning object area 12 Temperature sensor 14 Differential pressure gauge 15 Flowmeter 16 Pressure control device 17 Outbound header 18 Return Header 20 Air-conditioner pump 20a Inverter 22 Piping 30 Temperature control device 31 First output adjustment device 32 Second output adjustment device X Air-conditioner piping system Y Heat medium main transfer loop Z Temperature control device in control target area

Claims (7)

An air conditioner pump in which the rotation speed of a motor for driving an impeller can be controlled by an inverter, an air conditioner having a coil for flowing a heat medium for heat exchange with air to be controlled, and a two-way valve whose opening degree can be adjusted. And in order the air-conditioner piping system that is arranged in each of the plurality of air-conditioning target areas,
A temperature control device for the control target region for controlling the rotation speed of the air conditioner pump of the air conditioner piping system and the opening of the two-way valve;
A heat source device for supplying a temperature-adjusted heat medium to each air conditioner piping system;
A forward main pipe connected via a first forward header to each air conditioner pump inlet side outgoing pipe and the heat source device outlet side of each air conditioner piping system;
A return main pipe connected via a return header to each of the two-way valve outlet side return pipes of each of the air conditioner piping systems and the inlet side of the heat source device;
A primary pump that is located on the inlet side of the heat source device of the return main pipe and conveys the heat medium at a head for a pressure loss from the return header to the first forward header;
A secondary pump capable of inverter-controlling the rotational speed of a motor that drives an impeller disposed downstream of the first forward header of the forward main pipe that conveys the heat medium to each of the air conditioner piping systems;
A second forward header connected in the middle of the outgoing main pipe on the discharge side of the secondary pump;
An inter-header bypass pipe connecting the first forward header and the return header;
A differential pressure gauge for measuring a differential pressure between the second forward header and the return header;
A pressure control device for controlling an inverter of the secondary pump based on a measured value of the differential pressure gauge;
A flow meter installed upstream of the return header of the return pipe,
The temperature control device of the control target area is
A temperature sensor for measuring an air temperature in a control target region for each of the plurality of air conditioning target regions;
A temperature indicating controller that outputs a primary control output as a result of PI calculation based on a deviation between a measured value from the temperature sensor and an air temperature set value of the control target region;
A first output adjusting device that adjusts and outputs a control output to the inverter of the air conditioning pump based on a primary control output from the temperature indicating controller;
A second output adjustment device that adjusts and outputs an opening control output of the two-way valve based on a primary control output from the temperature indicating controller, and the first output adjustment device and the second output adjustment By giving a difference in the adjustment allocation with the device, when the primary control output varies, the frequency adjustment of the inverter of the air conditioner pump is changed earlier than the opening adjustment of the two-way valve,
The pressure control device includes:
The load flow measurement value measured by the flow meter is inputted, the set value of the differential pressure is calculated by the relational expression between the load flow rate given in advance and the set differential pressure, and the differential pressure measurement value measured by the differential pressure meter is calculated. A heat medium piping system, wherein an inverter of the secondary pump is controlled by a pressure control output calculated based on a deviation from the set value of the differential pressure. The heat medium piping system according to claim 1,
The secondary pump controls the inverter of the air conditioner pump with respect to the air conditioner pump having the lowest lift among the air conditioner pumps while keeping all the two-way valves fully open, and the lift is 0 kPa. In a state where a predetermined flow rate is allowed to flow, a rated flow rate Q0 capable of processing a heat quantity obtained by summing up the rated heat loads of all the air conditioners, and a forward pipe of the air conditioner piping system including the air conditioner pump having the lowest lift. A heat medium piping system having a capability of being transported at a rated head P0 that can cover the pressure loss of the forward main pipe, the return main pipe, and the air conditioner piping system up to a return pipe connection point. In the heat medium piping system according to claim 1 or 2,
The pressure control device sets the differential pressure from the rated head P0 at the rated flow rate Q0 of the secondary pump, using the return differential pressure P0 at the rated flow rate Q0 as a reference point of the relational expression between the load flow rate and the set differential pressure. The heat medium piping system, wherein the value is changed in proportion to the square of the measured load flow rate value of the flow meter. In the heat medium piping system according to any one of claims 1 to 3,
Each air conditioner pump is rated to cover the pressure loss from the first forward header to the return header so that the rated flow rate of each air conditioner can be secured even if the head of the secondary pump is zero. A heat medium piping system characterized by having the ability to flow the rated flow at the head. In the heat medium piping system according to any one of claims 1 to 4,
The temperature control device in the control target region opens the two-way valve at the time of control by adjusting the rotation speed of the air conditioner pump, and when the rotation speed of the air conditioner pump becomes a lower limit value, The heat medium piping system, wherein the rotation speed of the air conditioner pump and the opening of the two-way valve are adjusted so as to be controlled by adjusting the opening. In the heat medium piping system according to any one of claims 1 to 5,
The two-way valve is a full-bore electric ball valve or butterfly valve having the same inner diameter as the return pipe when fully opened, and there is almost no increase in pressure loss compared to the front and rear pipes. In the heat medium piping system according to any one of claims 1 to 6,
Said 1st output adjustment apparatus and said 2nd output adjustment apparatus are ratio bias setting devices. The heat medium piping system characterized by the above-mentioned.

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