JP5284295B2 - Heat source control system and heat source control method - Google Patents

Description

  The present invention relates to a technique for determining and controlling the optimum number of operating heat source units in accordance with a change in a load state of an air conditioning heat source facility.

Conventionally, it is composed of a plurality of primary pumps including a plurality of heat source units and a plurality of secondary pumps that carry the air conditioning load, and one of the secondary pumps corresponds to an inverter. A two-pump heat source system is known as a heat source system considering energy saving. The control of such a heat source system basically includes a plurality of heat source machines and primary / secondary pumps that are divided in capacity with respect to peak load, such as an air handling unit (AHU) and a fan coil unit (FCU). In response to the load required by the air conditioning load, it is intended to cope with the partial load by operating with an appropriate number of heat source units and the number of primary and secondary pumps and output.
In this two-pump heat source system, a two-way valve is provided on the outlet side of the air-conditioning load, and a system having a variable flow rate by controlling the two-way valve is called a closed two-pump heat source system.

A control method according to the above-described closed two-pump heat source system will be described with reference to FIGS. FIG. 12 shows a schematic system diagram of a closed system two-pump heat source system.
As shown in FIG. 12, the closed two-pump heat source system connects the outgoing primary header and the return header with a communication pipe, and includes a plurality of secondary pumps on the air conditioning load side and a plurality of heat pumps on the heat source unit side. Primary pump. The secondary pump is responsible for the outgoing water primary header to the return water header. On the other hand, the primary pump is responsible for the return water header to the outgoing water primary header.

In the conventional control method, the control on the secondary pump side is the control of the number of pumps and the pressure of the outgoing water secondary header (water supply pressure) or the outgoing water primary header and the return water according to the load flow rate on the air conditioning load side. Control of an inverter of the secondary pump and a bypass valve (pressure relief valve) between the incoming and outgoing headers to maintain a differential pressure between the headers (same pressure because they are connected by a communication pipe) is performed. The inverters of the secondary pumps are rarely incorporated in all units, and in most cases, only one unit is incorporated (see, for example, Patent Document 1 and Patent Document 2).
Further, the heat source unit is subjected to determination processing based on the process values of the water temperature, the return water temperature, and the load flow rate, and the number of heat source units is controlled. The primary pump operates in conjunction with the heat source machine as an auxiliary machine of the heat source machine.

  For example, in the case of the control method of the heat source system disclosed in Patent Document 1, the energy of the heat source unit is calculated, the energy of the secondary pump is calculated, and the energy consumption of the air conditioning load calculated from the energy of the heat source unit The energy consumption of the heat source system is calculated from the energy consumption of the secondary pump calculated from the energy of the secondary pump, and the water supply temperature at which this value is minimized is calculated.

  In the case of the control method of the heat source system disclosed in Patent Document 2, the total value of the rated flow rates of the primary pump in operation is obtained as the primary flow rate, and the flow rate of the heat source water (load) returned to the return water header The secondary flow rate is compared with the secondary flow rate, and if the secondary flow rate is greater than the primary flow rate, the number of operating heat source units is increased. .

In general, the number of heat source units in a closed two-pump heat source system is controlled by calculating the load heat amount and comparing it with the heat source rated heat amount (heat source capacity). When the water temperature decreases, the level is reduced (reverse during heating), and when the water temperature rises (reverse during heating operation), a correction increase / decrease determination is performed to increase the level.
In the basic increase / decrease stage determination, the load heat quantity is calculated by multiplying the load flow rate by the temperature difference between the forward water temperature and the return water temperature. In addition, the heat source machines are subjected to increase / decrease stage processing one by one, and an effect waiting time is provided after the increase / decrease stage processing.

  The reason why the correction increase / decrease stage determination is necessary is that even when the number of heat source units is excessive with respect to the air conditioning load as shown in FIG. (In other words, the air conditioning load is small and the load flow rate is small), the communication pipe flows from the outgoing water primary header toward the return water header, and the return water temperature decreases. That is, the tendency of the excessive number of heat source units is detected by the return water temperature, and the heat source unit is corrected to be reduced.

  On the other hand, as shown in FIG. 13 (2), if the flow rate on the air conditioning load side is excessive (the number of heat sources is too small), the communication pipe will flow from the return water header to the outgoing water primary header. The water supply temperature will rise above the outlet temperature of the machine. In other words, a tendency for the number of heat source units to be insufficient is detected based on the water temperature, and the heat source unit is corrected to be increased. It is correction increase / decrease stage control to optimize the number of heat source units in this way.

The number of secondary pumps is controlled based on the load flow rate. Specifically, the required number of operating units is determined by comparing the load flow rate and the rated flow rate of the secondary pump.
Moreover, the inverter control of the secondary pump is performed based on the pressure (water supply pressure) of the outgoing water secondary header.
The pressure relief valve is also controlled based on the pressure of the outgoing secondary header (water supply pressure). Normally, the pressure relief valve is opened only when the pressure cannot be adjusted by the inverter by setting the pressure higher than the water supply pressure setting of the inverter control of the secondary pump.

Next, problems of the conventional control method in the above-described closed two-pump heat source system will be described.
In the conventional control method described above, the control of the number of heat source units, the control of the number of secondary pumps, the inverter control of the secondary pump, and the control of the pressure relief valve are independent controls having separate determination measurement points. . As shown in the schematic system diagram of FIG. 12, the conventional control method system includes a load control system that is a control around the air conditioning load, a transport control system that transports heat source water (cold / warm water) to the air conditioning load, and an air conditioning load. The heat source control system determines the appropriate number of heat source units.
FIG. 14 shows the divisions on the control flow diagram in these three divisions.

  As shown in FIG. 14, it can be seen that each control module affects other measurement points while causing the measurement value of the direct control target point to follow the target value. For example, in order to follow the increase in the flow rate of the air conditioning load, the load heat quantity changes simultaneously as a result of increasing the number of stages by controlling the number of secondary pumps. In this case, the flow rate change appears immediately, but the reaction of the return water temperature is slow and a time delay occurs. As a result, when the flow rate is increased by increasing the secondary pump stage, the load heat amount is calculated by multiplying the load flow rate by the temperature difference between the incoming water temperature and the return water temperature as described above. It seems as if it has increased rapidly.

  In order to make a proper determination even in such a situation, each control module has a determination waiting time so as not to immediately process the change of the situation. Further, an effect waiting time after processing is provided so that the next processing is not performed until a certain effect appears after the stage increasing processing as in the case of unit control. The lengths of the determination waiting time and the effect waiting time must be adjusted by each control system as shown in FIG. In other words, in the case of a load control system, the control judgment cycle is shortened to react relatively quickly, whereas in the case of a heat source control system, before starting and stopping such as a delay in start-up after startup or a process after stopping, The determination waiting time is set longer in order to determine the determined situation in consideration of the time required for post-processing processing, and the setting value is set longer in order to determine the effect after the increase / decrease stage processing is performed.

  That is, in the conventional control method, there is a problem in that the control modules interfere with each other unless the determination waiting time and the effective waiting time are appropriately set, resulting in an unstable control state.

In addition, as described above, there is a problem that the control modules interfere with each other, resulting in an unstable control state. Therefore, in order to ensure cooperation between the control modules, it is necessary to check the safety factor for each setting value. There is.
This will be described by taking the relationship between the inverter control of the secondary pump and the number control as an example.

  As shown in FIG. 15, the set value of the secondary pump unit control is set based on the rated flow rate for the increase / decrease stage setting of the secondary pump. However, since the discharge flow rate of the secondary pump changes with the required flow rate on the load side, the differential pressure between the outgoing water primary header and the outgoing water secondary header changes. Therefore, the discharge flow rate of the secondary pump is set based on the rated flow rate in the design specifications, but actually changes depending on the condition on the air conditioning load side. Therefore, it often occurs that the secondary pump is increased before the frequency of the inverter of the secondary pump reaches the maximum. Conversely, in order to avoid this situation, it is only necessary to set the secondary pump stage setting value higher, but if it is set too high, the inverter of the secondary pump reaches the maximum frequency. However, since the situation where the increased stage set flow rate is not reached occurs, the secondary pump cannot increase the stage and adversely affects the air conditioning load.

  Considering these things, in practice, a lower flow rate setting is often performed so that the secondary pump can increase the stage regardless of the pipe resistance on the air conditioning load side. As a result, as described above, inverter control often increases the number of stages without reaching the maximum frequency, which causes energy loss of conveyance power.

  Further, as another example, the control of the number of heat source units is the same. The control of the number of heat source units is also basically performed based on the rated capacity standards in the design specifications for the increase / decrease stage setting values. However, the rated capacity varies greatly depending on, for example, a difference in cooling water temperature for a water-cooled heat source and a difference in outside air temperature for an air-cooled heat source. Even in such a case, the capacity of the heat source machine under the worst conditions of the outside air is set as a rating, and the setting is based on this, so it tends to be operated with a larger number of units.

  The same applies to the set value of pressure control for inverter control of the secondary pump. Since this set value is the water supply pressure required at the maximum load, the water supply pressure is excessive in the low load situation that occupies many throughout the year. Moreover, in order to maintain this water supply pressure, the inverter can be controlled only up to about 35 to 45 Hz even in the lowest load range.

  As described above, in the conventional control method, looking at the safety factor in the set value for each control module is necessary for the cooperation of the control modules, and also causes energy loss.

JP 2003-262384 A JP 2006-153324 A

In view of the above situation, the present invention realizes a stable control state of each control module by operating each control module with a common measurement item, as compared with the conventional control method related to a closed two-pump heat source system. And it aims at providing the heat source control system and heat source control method which can reduce the energy loss of conveyance power.

  The inventors have conducted various examinations and experiments in order to save energy in the heat source system design and construction work of the closed system two-pump heat source system, and as a result, the heat source control system according to the present invention and A heat source control method was completed.

  In order to achieve the above object, a heat source control system according to a first aspect of the present invention includes a plurality of heat source devices that generate heat source water to supply heat source water (cold / warm water) according to an air conditioning load, and a heat source device. As an auxiliary machine, a plurality of primary pumps that transport the heat source water, a primary water header that mixes the heat source water from the heat source machine, a secondary water header, and a heat source water from the primary water header Heat is exchanged between the multiple secondary pumps to be sent to the secondary header, the air conditioning load that receives the supply of heat source water from the secondary pump, the two-way valve for the air conditioner provided on the outlet side of the air conditioning load, and the air conditioning load. In a closed two-pump heat source system comprising a return water header to which the heat source water is returned, and a communication pipe connecting the outgoing primary header and the return water header, the following (1-1) to (1-3) It has the configuration requirements.

(1-1) A control two-way valve is provided in the communication pipe.
(1-2) A pressure sensor for detecting the pressure of the primary water header is provided.
(1-3) The control two-way valve is controlled using the pressure of the primary water flow header necessary for securing the minimum flow rate for protecting the heat source machine as a target value.

By providing such a configuration requirement, the capacity of the primary pump can be effectively used for conveyance to the air conditioning load side.
When the discharge flow rate of the primary pump is excessive with respect to the discharge flow rate of the secondary pump (that is, when the air-conditioning load side is in a low load state with respect to the capacity of one heat source unit), the excess flow amount is connected to the communication pipe. It returns to the heat source machine side via. By utilizing this fact, the control two-way valve provided in the communication pipe is appropriately throttled, so that it is possible to circulate to the air conditioning load side at the head of the primary pump without operating the secondary pump.

  Further, the control two-way valve performs PID control so that the outgoing primary header pressure (Ps1_pv) becomes the target value (Ps1_sp1). Specifically, the method of determining the pressure of the target value (Ps1_sp1) is the control 2 provided in the communication pipe in a state where all the two-way valves for the air conditioner on the secondary side are fully closed from the viewpoint of equipment protection. This is a method of closing the direction valve and setting the flow header pressure immediately before the heat source machine stops due to a drop in flow rate as a target value. That is, even when the load flow rate on the secondary side becomes 0 (zero), control is performed with the goal of ensuring the pressure of the outgoing primary header so that the heat source machine can flow the minimum flow rate that does not cause an error stop. Therefore, as described in (1-2) above, a pressure sensor for detecting the pressure of the outgoing primary header is provided.

  The role of the primary pump in the conventional two-pump heat source system is to secure a flow rate necessary for the heat source machine against the resistance on the primary side of the return header. On the other hand, the role of the primary pump in the heat source control system of the present invention is to carry the heat source water to the air conditioning load side in addition to ensuring the flow rate required for the heat source machine.

  A heat source control system according to a second aspect of the present invention includes a plurality of heat source devices that generate heat source water and an auxiliary device for the heat source device to supply heat source water (cold / warm water) according to an air conditioning load. A plurality of primary pumps that transport water, a primary water header that mixes heat source water from a heat source machine, a secondary water header, and a heat source water from the primary water header are sent to the secondary water header. A plurality of secondary pumps, an air-conditioning load that receives supply of heat source water from the secondary pump, a two-way valve for an air conditioner provided on the outlet side of the air-conditioning load, and heat source water that is heat-exchanged by the air-conditioning load are returned. A closed two-pump heat source system including a return water header and a communication pipe connecting the outgoing water primary header and the return water header, and having the following structural requirements (2-1) to (2-3) It is.

(2-1) A control two-way valve is provided in the communication pipe.
(2-2) A pressure sensor is provided for detecting a differential pressure between the primary water header and the return water header.
(2-3) The control two-way valve is controlled using a differential pressure necessary for securing a minimum flow rate for protecting the heat source unit as a target value.

By providing such a configuration requirement, the capacity of the primary pump can be effectively used for conveyance to the air conditioning load side.
When the discharge flow rate of the primary pump is excessive with respect to the discharge flow rate of the secondary pump (that is, when the air-conditioning load side is in a low load state with respect to the capacity of one heat source unit), the excess flow amount is connected to the communication pipe. It returns to the heat source machine side via. By utilizing this fact, the control two-way valve provided in the communication pipe is appropriately throttled, so that it is possible to circulate to the air conditioning load side at the head of the primary pump without operating the secondary pump.

Moreover, the heat source control system according to the first aspect or the second aspect of the present invention includes the following constituents (a) to (c).
(A) A terminal air conditioner inlet pressure sensor is provided at the inlet of the air conditioning load that is the farthest end in terms of pressure loss.
(B) Control of the number of secondary pumps, inverter control of the secondary pumps, and pressure relief valve control of the secondary pumps based on the measured value of the terminal air conditioner inlet pressure sensor.
(C) The number of heat source devices is controlled based on the pressure sensor provided in the outgoing water primary header or the measured value of the pressure sensor that detects the differential pressure between the outgoing water primary header and the return water header.

By providing such a configuration requirement, the number of secondary pumps, the inverter control of the secondary pumps, the pressure relief valve control of the secondary pumps, the control of the control two-way valve provided in the communication pipe, and the heat source machine All the control of the number control can be determined by the pipe pressure.
Thereby, while the control modules in the conventional control method are operated at different determination measurement points, all the control modules in the control method of the heat source control system of the present invention can be operated by a common measurement item called pressure. It is.

  In the inverter control of the secondary pump, when the target value (Pe_sp) of the terminal air conditioner inlet pressure is set and the air conditioning load increases, the two-way valve for the air conditioner operates in the opening direction and the required flow rate on the secondary side increases. Will do. When the secondary required flow rate increases, the terminal air conditioner inlet pressure decreases. In order to follow this decrease in the inlet air conditioner inlet pressure, the inverter output of the secondary pump increases. Thus, the number of secondary pumps is controlled.

As described above, the ability of the primary pump can be utilized to the maximum extent for conveyance to the air conditioning load side by the control two-way valve newly provided in the communication pipe. Thereby, after fully utilizing the head of the primary pump for conveyance to the air conditioning load side, only the amount necessary for maintaining the terminal air conditioner inlet pressure can be adjusted by the secondary pump inverter.
Thereby, in the inverter control of the secondary pump, it is possible to perform the control from 0 Hz to the full range without providing the minimum frequency setting. In the inverter control of the secondary pump, by enabling control from 0 Hz, the primary pump head can be fully utilized and the necessary output can be adjusted by the inverter output. On the other hand, if the required flow rate on the secondary side is very small, the control two-way valve of the communication pipe is opened to ensure the minimum flow rate of the heat source unit.

  Further, in the pressure relief valve control of the secondary pump in the heat source control system of the present invention described above, it is preferable that the pressure relief valve is controlled only when one secondary pump is operating.

  The control purpose of the pressure relief valve of the secondary pump between the outgoing water primary header and the outgoing water secondary header is pressure adjustment when the inverter machine of the secondary pump fails, as in the conventional control method. By controlling the operation only when one secondary pump is operating, the pressure of the rated pump is released when the secondary pump is operating the inverter machine and the rated pump, and the stage is reduced. It can be prevented that it becomes impossible.

Next, the heat source control method of the present invention is a control method of the heat source control system according to the first aspect or the second aspect of the present invention,
(S1) When the control two-way valve is closed with all the two-way valves for air conditioners fully closed, control is performed using the pressure or differential pressure immediately before the heat source machine stops due to a drop in flow rate as the target value. And a step of controlling the two-way valve.

The heat source control method of the present invention is a control method of the heat source control system of the present invention described above,
(S1) When the control two-way valve is closed in a state where all the two-way valves for the air conditioner are fully closed, the pressure of the outgoing primary header immediately before the heat source machine stops due to a drop in the flow rate or the Controlling the control two-way valve using a differential pressure between the outgoing water primary header and the return water header as a target value;
(S2) controlling the number of secondary pumps based on the measured value of the terminal air conditioner inlet pressure sensor;
(S3) controlling the inverter of the secondary pump based on the measured value of the terminal air conditioner inlet pressure sensor;
(S4) controlling the pressure relief valve of the secondary pump based on the measured value of the terminal air conditioner inlet pressure sensor;
(S5) controlling the number of heat source units based on the measured value of the pressure sensor of the outgoing water primary header or the pressure sensor for detecting the differential pressure between the outgoing water primary header and the returning water header; ,
All of which are controlled based only on the pressure in the pipe, and make full use of the head of the primary pump for conveyance to the air conditioning load side, and then only the flow rate necessary for maintaining the inlet air pressure at the terminal air conditioner is supplied to the secondary pump. It is set as the structure adjusted by inverter control .

  The control of the number of heat source units by the outgoing primary header pressure in (S5) will be described. The number control of the heat source units is performed by performing the increase / decrease stage of the heat source units by judging with the primary water pressure of the going water. That is, as the secondary side required flow rate increases, the pressure in the outgoing primary header decreases. In order to follow the target set value against this pressure drop, the control two-way valve of the communication pipe is controlled in the closing direction. Further, when the secondary required flow rate increases, the valve opening degree of the control two-way valve of the communication pipe is finally fully closed. When this state is reached, the pressure cannot be followed and the pressure gradually decreases from the target value (Ps1_sp1). When this decreases to a certain set value level (Ps1_sp2), the heat source unit is increased. On the other hand, when the required flow rate on the secondary side decreases during the stage increase of the heat source unit, the pressure of the outgoing primary header increases, and the stage is reduced when the pressure returns to a certain set value level (Ps1_sp3).

  According to the heat source control system and the heat source control method of the present invention, compared with the conventional control method of the closed system two-pump heat source system, each control module operates by a common measurement item, and the stable control state of each control module In addition, the energy loss of the conveyance power can be reduced by effectively utilizing the primary pump head.

  In addition, the heat source control system and the heat source control method of the present invention replace the manual valve of the communication pipe with the control two-way valve, and the pressure measurement sensor of the outgoing water primary header and the inlet pressure of the terminal air conditioner with respect to the existing system. It can be executed simply by installing a sensor for measuring the current, and can be easily and inexpensively introduced into an existing system.

1 is a schematic system diagram of a heat source control system of Embodiment 1. FIG. It is explanatory drawing of the role of a communicating pipe and a control 2 way valve. (1) shows the flow of heat source water in the communication pipe when the demand on the air conditioning load side is a low load with respect to the capacity of one heat source unit. (2) shows the flow of heat source water circulated in the primary pump head on the air conditioning load side when a control two-way valve is installed in the communication pipe. It is a graph which shows the pipe water pressure distribution with respect to the flow path of the heat source control system of Example 1, and the relationship of control. The control flow of the inverter machine of a secondary pump is shown. The control flow of the number control of a secondary pump is shown. An operation time chart for controlling the number of secondary pumps is shown. The control flow of the pressure relief valve of the secondary pump between the outgoing water primary header and the outgoing water secondary header is shown. The control flow of the control pipe two-way valve is shown. The control flow of the number control of the heat source machine is shown. An operation time chart for controlling the number of heat source units is shown. It is a graph which shows the relationship between a primary side flow volume and a primary pump outlet pressure. It is a schematic system diagram of a conventional closed two-pump heat source system. It is explanatory drawing of the communicating pipe which adjusts the primary side and secondary side flow volume in the conventional heat source system. It is a control flow figure showing a control system division of a heat source control method in the conventional heat source system. It is explanatory drawing of the operation timing of the number control of the secondary pump in the conventional heat source system. 6 is a schematic system diagram of a heat source control system according to Embodiment 2. FIG. FIG. 6 is a schematic system diagram of a heat source control system according to a third embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The scope of the present invention is not limited to the following examples and illustrated examples, and various changes and modifications can be made.

FIG. 1 is a schematic system diagram of a heat source control system according to the first embodiment. As shown in FIG. 1, the heat source control system according to the first embodiment includes two heat source units (1a, 1b) that generate heat source water and two primary pumps that transport the heat source water as an auxiliary machine of the heat source unit. (2a, 2b), the outgoing water primary header 3 and the outgoing water secondary header 4 that mix the heat source water from the heat source devices (1a, 1b), and the outgoing water 2 from the outgoing water primary header 3. Two secondary pumps (8a, 8b) to be sent to the next header 4, an air conditioning load 5 that receives the supply of heat source water from the secondary pumps (8a, 8b), and an air conditioner provided on the outlet side of the air conditioning load 5 It comprises a machine two-way valve 10, a return water header 6 to which the heat source water exchanged by the air conditioning load 5 is returned, and a communication pipe 11 that connects between the outgoing primary header 3 and the return water header 6. In addition to the conventional closed two-pump heat source system,
(1) A control two-way valve 20 is provided in the communication pipe 11,
(2) A forward water primary header pressure sensor P2 for detecting the pressure in the pipe of the forward water primary header 3 is provided,
(3) A terminal air conditioner inlet pressure sensor P3 is provided at the inlet of the air conditioning load 5 corresponding to the farthest end in terms of pressure loss,
(4) The communication pipe 11 with the pressure required to secure the minimum flow rate for protecting the heat source units (1a, 1b), specifically, with the air conditioner two-way valve 10 fully closed. When the control two-way valve 20 is closed, the pressure immediately before the heat source machine (1a, 1b) stops due to a decrease in the flow rate is used as the target value of the pipe pressure of the outgoing primary header 3, and the control two-way The valve 20 is controlled.

In the schematic system diagram (FIG. 1) of the heat source control system according to the first embodiment, the concept of the control system classification, that is, the load control system A, the conveyance control system B, and the heat source control system C are similar to FIG. Indicates the category.
The conveyance control system is in a range including the primary pumps (2a, 2b), and the heat source control system is only outlet temperature control which is main body control of the heat source machines (1a, 1b). The inclusion of the primary pumps (2a, 2b) in the transport control system means that the primary pumps (2a, 2b) are auxiliary devices that are linked to the heat source units (1a, 1b), so that the heat source unit in the conventional control method This means that the number control is included in the transport control system.

In the heat source control system of the first embodiment, the number of secondary pumps (8a, 8b) is controlled, the secondary pump inverter 8a is controlled, the secondary pump pressure relief valve 9 is controlled, and the communication pipe 11 is connected. The control of all control modules of the control two-way valve 20 and the number control of the heat source units (1a, 1b) are determined by the pipe pressure.
Specifically, for the control of the number of secondary pumps (8a, 8b), the control of the inverter unit 8a of the secondary pump, and the control of the pressure relief valve 9 of the secondary pump, the measurement process of the terminal air conditioner inlet pressure sensor P3 Determine and control based on the value. Further, the control of the control two-way valve 20 provided in the communication pipe 11 and the control of the number of heat source units (1a, 1b) are determined and controlled based on the measurement process value of the pressure sensor P2 of the outgoing water primary header 3.

As shown in FIG. 1, control of the number of secondary pumps (8a, 8b), control of the inverter unit 8a of the secondary pump, control of the pressure relief valve 9 of the secondary pump, and control provided in the communication pipe 11 All the control modules such as the control of the two-way valve 20 and the control of the number of heat source devices (1a, 1b) fall under the category of the conveyance control system B.
As shown in FIG. 1, the instrumentation equipment indispensable for these controls includes a forward water primary header pressure sensor P2 for detecting the pressure in the pipe of the forward water primary header 3, and an air conditioning load corresponding to the farthest end in terms of pressure loss. 5 are the terminal air-conditioner inlet pressure sensor P3 and the control two-way valve 20 provided in the communication pipe 11 at the inlet of 5.

  A control two-way valve 20 is installed in the communication pipe 11 connecting between the outgoing water primary header 3 and the return water header 6, and the pipe internal pressure (Ps1_pv) of the outgoing water primary header 3 is set to the target value ( PID control is performed so that Ps1_sp1), and the heads of the primary pumps (2a, 2b) are effectively used. The role of the primary pump in the conventional two-pump heat source system is to secure a necessary flow rate in the heat source machine against the resistance on the primary side of the return header. As shown in FIG. 2 (1), when the discharge flow rate of the primary pump is larger than the discharge flow rate of the secondary pump, that is, when the load side is in a low load state with respect to the capacity of one heat source unit. The excess flow rate is returned to the heat source machine (1a, 1b) via the communication pipe 11. That is, the head of the primary pump (2a, 2b) is discarded. In this case, as shown in FIG. 2 (2), if the control two-way valve 20 is installed in the communication pipe 11, and the control two-way valve 20 is appropriately throttled, the secondary pumps (8a, 8b) are operated. There may be a load flow zone that circulates at the head of the primary pump (2a, 2b) even if not.

Furthermore, by making it possible to control the inverter pump 8a of the secondary pump from 0 Hz without setting the minimum frequency, it is necessary to use all the heads of the primary pumps (2a, 2b). It is possible to adjust the output only by the inverter unit 8a of the secondary pump.
On the other hand, when the required flow rate on the secondary side is very small, the control two-way valve 20 of the communication pipe 11 is opened to ensure the minimum flow rate of the heat source machine (1a, 1b). That is, the control two-way valve 20 of the communication pipe 11 performs the minimum flow rate compensation of the heat source unit so that the heat source unit (1a, 1b) does not stop due to a decrease in the flow rate. Therefore, the control two-way valve 20 of the communication pipe 11 is a heat source operation compensation two-way valve.

  This control target setting value (Ps1_sp1) is determined by closing the control two-way valve 20 of the communication pipe 11 in a state where all the two-way valves for the air conditioner on the secondary side are fully closed. 1a, 1b) is a method in which the pressure value of the outgoing primary header 3 immediately before an error stop due to a decrease in flow rate is set as a target set value. That is, even when the secondary-side flow rate becomes 0, the target is controlled to ensure the outgoing water pressure when the heat source machine can flow the minimum flow rate that does not cause an error stop.

Next, the relationship between the flow path and the pipe water pressure in the heat source control system of the first embodiment will be described. FIG. 3 is a graph showing the relationship between the distribution of water pressure in the pipe and the control with respect to the flow path of the heat source control system according to the first embodiment. In addition, in FIG. 3, the case where the case where the heat source is on the lower floor such as the basement and the end load is on the upper floor is assumed is shown. As shown in FIG. 3, the pipe pressure (Ps1_pv) of the outgoing primary header 3 is adjusted by controlling the two-way valve 20 of the communication pipe 11, and the terminal pressure is controlled by controlling the inverter 8a of the secondary pump. It is based on adjusting.
That is, the control modules of the conventional control method operate at different determination measurement points. However, all of the control modules of the present invention operate according to a common measurement item called pipe pressure. This is effective for linking the control modules without loss.

(About secondary pump inverter control)
The control of the inverter unit 8a of the secondary pump is controlled by the inlet pressure of the air conditioner at the farthest end in terms of pressure loss (referred to as “terminal air conditioner inlet pressure” or “terminal pressure” in the present specification and drawings). If an appropriate inlet / outlet differential pressure can be secured in the farthest end air conditioner (AHU, FCU, etc.), an appropriate flow rate will flow. If the differential pressure of the air conditioner at the farthest end can be secured, the other air conditioners that are close to the pressure loss will also secure the differential pressure, so that an appropriate flow rate will flow. That is, it is very efficient to control by the terminal pressure.

  FIG. 4 shows a control flow of the inverter device of the secondary pump. As shown in FIG. 4, the control of the inverter unit of the secondary pump inputs the process value (Pe_pv) of the terminal air conditioner inlet pressure (step S11), and the terminal air conditioner inlet pressure becomes the target value pressure (Pe_sv). Thus, the inverter output of the secondary pump is PID controlled (step S12).

  Further, by providing the control two-way valve 20 in the communication pipe 11, the primary pump capacity can be used for the secondary side conveyance. In other words, after fully utilizing the primary pump head for the secondary side conveyance, only the amount necessary for maintaining the terminal pressure can be adjusted by the inverter unit 8a of the secondary pump. For this reason, the inverter machine 8a of the secondary pump can be controlled in a full range of 0 to 60 Hz, for example.

In the conventional control method, the secondary side conveyance is performed only by the secondary pump. And control of the inverter machine of a secondary pump is control which compensates water supply pressure. Accordingly, since the water supply pressure is maintained even at the minimum load, as a result, the inverter frequency can only be lowered to about 35 to 45 Hz.
However, in the heat source control system of the first embodiment, since a part of the primary pump head is used for the secondary side conveyance, the frequency of the inverter unit 8a of the secondary pump can be lowered as compared with the conventional control method. In some situations, it can be lowered to 0 Hz.

  As for the low speed operation of the secondary pump, the motor may be burned out when operating at a low speed. For this reason, there is a case where a minimum frequency setting of 20 to 30 Hz is provided for inverter control. However, in the case of a centrifugal pump generally used for an air conditioning pump, unlike a volumetric pump such as a gear pump or a plunger pump (reciprocating pump), the motor does not burn out at a low speed. The control of the inverter unit 8a of the next pump can be controlled in a full range from 0 Hz.

(About control of the number of secondary pumps)
Regarding the control of the number of secondary pumps (8a, 8b), when the air conditioning load 5 increases, the two-way valve 10 for the air conditioner operates in the opening direction, and the required flow rate on the secondary side increases. When the required flow rate on the secondary side increases, the terminal pressure decreases, and the output of the inverter unit 8a of the secondary pump increases to follow this. However, if the air conditioning load 5 further increases and the required flow rate increases, the output of the inverter 8a eventually becomes maximum, and the inverter 8a cannot maintain the target value (Pe_sp) of the terminal pressure and gradually decreases. Become. When this lowering level falls below a predetermined level (Pe_sp-Dif_sp1), the rated secondary pump 8b increases in stage.
On the other hand, when the terminal pressure rises to a predetermined level (Pe_sp + Dif_sp2) from the target value of the end pressure, the secondary pump is decelerated.

FIG. 5 shows a control flow for controlling the number of secondary pumps. FIG. 6 shows an operation time chart for controlling the number of secondary pumps.
As shown in the control flow of FIG. 5 and the operation time chart of FIG. 6, the secondary pump unit number control inputs the process value (Pe_pv) of the terminal air conditioner inlet pressure (step S21). It is determined whether or not the target value pressure (Pe_sv) has decreased by the lower threshold (Dif_Pe1) or more (step S22). When the determination waiting time has elapsed (step S23), the number of secondary pumps is increased ( Step S24).
Further, the process value (Pe_pv) of the terminal air conditioner inlet pressure is input (step S21), and it is determined whether or not the terminal air conditioner inlet pressure has returned from the target value pressure (Pe_sv) to the upper threshold (Dif_Pe2) or more. (Step S25) When the determination waiting time has elapsed (Step S26), the number of secondary pumps is reduced (Step S27).

(Secondary pump pressure relief valve control)
The control of the pressure relief valve 9 between the primary water header 3 and the secondary water header 4 is also controlled by the end pressure. The control purpose of the pressure relief valve 9 is pressure adjustment when the inverter machine 8a of the secondary pump fails, as in the conventional control method.
In the heat source control system of the first embodiment, control of the pressure relief valve 9 is performed only when the secondary pump is in operation.

  FIG. 7 shows a control flow of the pressure relief valve 9. As shown in FIG. 7, the pressure relief valve 9 is controlled by inputting the process value (Pe_pv) of the terminal air conditioner inlet pressure (step S31) and determining whether or not the terminal air conditioner inlet pressure has increased. (Step S32) Only when the single secondary pump is operated (Step S33), the opening degree of the pressure relief valve 9 is PID controlled so that the terminal air conditioner inlet pressure becomes the target value pressure (Pe_sv) (Step S33). S34).

  By controlling the pressure relief valve 9 when only one secondary pump is in operation, when the secondary pump is operating both the inverter 8a and the rated pump 8b, It prevents that the pressure of the rated pump 8b is released and the secondary pump cannot be stepped down.

(About control of the number of heat source units)
In the control of the number of heat source units (1a, 1b) in the first embodiment, the increase / decrease stage is performed based on the pressure in the pipe of the outgoing primary header 3. As the required flow rate on the secondary side increases, the pressure in the pipe of the outgoing primary header 3 decreases. In order to follow the target set value against this pressure drop, the control two-way valve 20 of the communication pipe 11 is controlled in the closing direction. Further, when the secondary required flow rate increases, the valve opening degree of the control two-way valve 20 is finally fully closed. Then, the pressure cannot be followed and the pressure gradually decreases from the target value (Ps1_sp1). When the temperature is lowered to a predetermined set value level (Ps1_sp2), the heat source unit is increased.
On the other hand, if the required flow rate on the secondary side decreases during the stage increase of the heat source unit, the pressure in the pipe of the outgoing primary header 3 increases. When returning to a predetermined set value level (Ps1_sp3), the heat source unit is destaged.
FIG. 10 shows an operation time chart for controlling the number of heat source units described above.

  FIG. 8 shows a control flow of the control two-way valve 20 of the communication pipe 11. As shown in FIG. 8, the control value of the communication pipe 11 is controlled by inputting the process value (Ps1_pv) of the in-pipe pressure of the outgoing water primary header 3 (step S41). The control two-way valve 20 is PID-controlled so that the in-pipe pressure becomes the target value pressure (Ps1_sv) (step S42).

FIG. 9 shows a control flow for controlling the number of heat source units.
As shown in FIG. 9, the control of the number of heat source units inputs the process value (Ps1_pv) of the pipe pressure of the outgoing primary header 3 (step S51), and the pipe pressure of the outgoing primary header 3 is the target pressure. It is determined whether or not it has decreased from (Ps1_sv) to a step increase set value (Ps1_sp2) or less (step S52). When the determination waiting time has elapsed (step S53), the number of heat source units is increased (step S54). ).
Further, the process value (Ps1_pv) of the in-pipe pressure of the outgoing water primary header 3 is input (step S51), and the in-pipe pressure of the outgoing water primary header 3 is greater than the target value pressure (Ps1_sv) by the step set value (Ps1_sp3) or more. (Step S55), and when the determination waiting time has elapsed (step S56), the number of heat source units is reduced (step S57).

  Here, how to determine each set value will be described. First, the reference pressure (Ps1_0) is the pressure in the pipe of the outgoing water primary header 3 when the entire heat source control system is stopped. This pressure value is the pressure in the pipe of the return water header 6 to which the expansion tank 7 is connected when the heat source control system is stopped and the heat source water is not flowing.

  Next, how to determine the stage increase set value is that when the required flow rate on the secondary side increases, the pressure in the pipe of the outgoing primary header 3 will decrease, but will eventually decrease to near the reference pressure (Ps1_0). What is necessary is just to increase a heat source machine. This is because if the pipe pressure (Ps1_pv) in the outgoing primary header 3 is higher than the reference pressure (Ps1_0), the primary pump has a margin. That is, it can be determined that there is room in the capacity of the heat source machine.

  On the other hand, the fact that the in-pipe pressure (Ps1_pv) of the outgoing water primary header 3 is lower than the reference pressure (Ps1_0) can be determined that the capacity of the heat source machine is insufficient. Therefore, the vicinity of the reference pressure (Ps1_0) is used as the setting value for the step increase setting value.

  Next, the step reduction set value (Ps1_sp2) is higher than the reference pressure (Ps1_0), and is determined by performing a trial run adjustment between the valve control set values (Ps1_sp1) of the control two-way valve 20. As a specific set value, it is preferable to adjust with reference to an intermediate value between the reference pressure (Ps1_0) and the valve control set value (Ps1_sp1) of the control two-way valve 20. This is because the valve control set value (Ps1_sp1) of the control two-way valve 20 is a pressure for compensating the minimum flow rate of the heat source unit (usually about 50% of the rated flow rate) when the secondary side is fully closed. On the other hand, since the pressure value needs to be increased at the reference pressure (Ps1_0), it is appropriate to set it in the vicinity of the intermediate point.

  The actual increase / decrease stage processing is performed for a certain period of time (waiting for judgment) after the pipe pressure in the outgoing primary header 3 falls below the increase stage set value in the case of an increase stage, and above the reduction stage set value in the case of a reduction stage. Increase / decrease stage processing is performed after time).

FIG. 11 shows the relationship between the primary flow rate and the primary pump outlet pressure.
In FIG. 11, the reference pressure (Ps1_0) is the origin of the vertical axis. Therefore, when replacing with the in-pipe pressure of the outgoing water primary header 3, a value obtained by subtracting the heat source internal resistance (r) from the outlet pressure of the primary pump may be used.

  In FIG. 11, the increase / decrease stage of a heat source machine is demonstrated. First, when the load side demand increases during operation of one primary pump (one heat source unit), the control two-way valve operates in the opening direction and the flow rate increases. Finally, in order to allow the rated flow rate (Q1) to flow to the heat source, the outlet pressure of the primary pump will secure the heat source internal resistance (r1), so that the vicinity of (Ps1_0 + r1) shown in FIG. descend. If it falls more than this, it cannot respond to the resistance in the heat source machine, and the rated flow rate (Q1) cannot be secured. This vicinity becomes the step-up pressure point.

  On the other hand, when the load-side required flow rate decreases when two primary pumps (heat source units) are operating on the step-down side, the load-side air conditioner two-way valve 10 operates in the closing direction. The required flow rate decreases. Eventually, the vicinity of the flow rate for one primary pump (heat source machine) becomes the step-down pressure point. If the load-side required flow rate further decreases after the heat source unit is reduced, the pipe resistance increases. However, it is necessary to ensure the minimum flow rate of the heat source unit, and the pressure value at that time is the control two-way valve 20 of the communication pipe 11. This is the control target value. The step-down pressure point is intermediate between the reference pressure (Ps1_0) and the control target value of the control two-way valve 20. What should be noted regarding the setting is that the operation points of the two primary pumps (heat source units) after the stage increase are less than the set value for the stage reduction control, and one primary pump (heat source unit) after the stage reduction The operating point is to be greater than the step-up control set value. This is to avoid the phenomenon of hunting.

(Example 2)
In the heat source control system of the first embodiment, the pressure sensor P2 that detects the pressure of the outgoing water primary header is provided, and the pressure of the outgoing water primary header that is necessary to ensure the minimum flow rate for protecting the heat source machine is obtained. Although the control two-way valve 20 of the communication pipe 11 is controlled as a target value, the difference between the outgoing water primary header 3 and the returning water header 6 is used instead of the pressure sensor P2 that detects the pressure of the outgoing water primary header. A pressure sensor for detecting the pressure may be provided, and the control two-way valve 20 of the communication pipe 11 may control the differential pressure as a target value.

FIG. 16 shows a schematic system diagram of the heat source control system of the second embodiment. As shown in FIG. 16, the heat source control system according to the second embodiment includes two heat source units (1a, 1b) that generate heat source water and two primary pumps that transport the heat source water as an auxiliary device of the heat source unit. (2a, 2b), the outgoing water primary header 3 and the outgoing water secondary header 4 that mix the heat source water from the heat source devices (1a, 1b), and the outgoing water 2 from the outgoing water primary header 3. Two secondary pumps (8a, 8b) to be sent to the next header 4, an air conditioning load 5 that receives the supply of heat source water from the secondary pumps (8a, 8b), and an air conditioner provided on the outlet side of the air conditioning load 5 It comprises a machine two-way valve 10, a return water header 6 to which the heat source water exchanged by the air conditioning load 5 is returned, and a communication pipe 11 that connects between the outgoing primary header 3 and the return water header 6. In addition to the conventional closed two-pump heat source system,
(1) A control two-way valve 20 is provided in the communication pipe 11,
(2) A pressure sensor P4 for detecting a differential pressure between the outgoing water primary header 3 and the return water header 6 is provided,
(3) The communication pipe with the differential pressure necessary to secure the minimum flow rate for protecting the heat source unit (1a, 1b), specifically, with all the two-way valves 10 for the air conditioner fully closed. When the control two-way valve 20 of 11 is closed, the pressure immediately before the heat source machine (1a, 1b) stops due to a decrease in the flow rate is set as the target value of the pipe pressure of the outgoing water primary header 3, and the control 2 The direction valve 20 is controlled.

(Example 3)
In the heat source control system of Example 1 or Example 2, the pressure sensor (P2 or P4) which detects the pressure of the outgoing water primary header and the differential pressure between the outgoing water primary header 3 and the returning water header 6 is provided. The control two-way valve 20 of the communication pipe 11 was controlled with the pressure and differential pressure required to secure the minimum flow rate for protecting the heat source unit as the target values, but instead of the pressure sensor (P2 or P4) In addition, a flow rate sensor for measuring the flow rate passing through the heat source device (1a, 1b) is provided, and the control flow of the communication pipe 11 is controlled with the flow rate necessary for securing the minimum flow rate for protecting the heat source device as a target value. The valve 20 may be controlled.

FIG. 17 shows a schematic system diagram of the heat source control system of the third embodiment. As shown in FIG. 17, the heat source control system according to the second embodiment includes two heat source units (1a, 1b) that generate heat source water and two primary pumps that transport the heat source water as an auxiliary device of the heat source unit. (2a, 2b), the outgoing water primary header 3 and the outgoing water secondary header 4 that mix the heat source water from the heat source devices (1a, 1b), and the outgoing water 2 from the outgoing water primary header 3. Two secondary pumps (8a, 8b) to be sent to the next header 4, an air conditioning load 5 that receives the supply of heat source water from the secondary pumps (8a, 8b), and an air conditioner provided on the outlet side of the air conditioning load 5 It comprises a machine two-way valve 10, a return water header 6 to which the heat source water exchanged by the air conditioning load 5 is returned, and a communication pipe 11 that connects between the outgoing primary header 3 and the return water header 6. In addition to the conventional closed two-pump heat source system,
(1) A control two-way valve 20 is provided in the communication pipe 11,
(2) Provide flow rate sensors (F2, F3) for measuring the flow rates passing through the respective heat source units (1a, 1b),
(3) The control two-way valve 20 is controlled with a flow rate necessary for securing a minimum flow rate for protecting the heat source units (1a, 1b) as a target value.

  As described above, the heat source control system and the heat source control method of the present invention have been described in the heat source control system of the first to third embodiments. This is a control system and control method for a closed two-pump heat source system in which the air-conditioning load side is controlled by a two-way valve and has a variable flow rate. Compared with the general control method conventionally performed with respect to such a heat source system, this is a novel control method that can significantly reduce the power for conveying power. Closed two-pump heat source systems have been introduced to a large number of buildings and facilities since the latter half of the 1990s as a system that takes energy saving into consideration. With respect to these existing heat source systems, the heat source control system and the heat source control method of the present invention can be easily and inexpensively introduced. For existing heat source systems, it is possible to replace the manual valve on the communication pipe with a control two-way valve and install a pressure sensor for the outgoing primary header and a pressure sensor for measuring the inlet pressure of the terminal air conditioner. is there. By using the heat source control system and the heat source control method of the present invention, a high energy saving effect can be obtained, and therefore, introduction into an existing heat source system can be expected.

  The heat source control system and the heat source control method of the present invention are useful for a closed two-pump heat source system.

DESCRIPTION OF SYMBOLS 1a, 1b Heat source machine 2a, 2b Primary pump 3 Outbound primary header 4 Outbound secondary header 5 Air conditioning load 6 Return water header 7 Expansion tank 8a, 8b Secondary pump 9 Pressure relief valve 10 Two-way valve for air conditioner 11 Communication pipe 20 Communication pipe control 2-way valve A Load control system B Transport control system C Heat source control system INV Inverter machine P1, P2, P3, P4 Pressure sensor T1-T7 Temperature sensor F1, F2, F3 Flow meter

Claims (6)

In order to supply heat source water (cold / warm water) according to the air conditioning load, a plurality of heat source units that generate the heat source water, a plurality of primary pumps that transport the heat source water as an auxiliary device of the heat source unit, and a heat source from the heat source unit A primary water header and a secondary water header that mix water, a plurality of secondary pumps that send heat source water from the primary water header to the secondary water header, and supply of heat source water from the secondary pump Receiving air conditioning load, a two-way valve for an air conditioner provided on the outlet side of the air conditioning load, a return water header to which heat source water exchanged by the air conditioning load is returned, and between the outgoing primary header and the return water header In a closed two-pump heat source system comprising a communication pipe connecting
A control two-way valve is provided in the communication pipe;
A pressure sensor for detecting the pressure of the往水primary header is provided,
A terminal air conditioner inlet pressure sensor is provided at the inlet of the air conditioning load, which is the farthest end in terms of pressure loss,
The control two-way valve is controlled with the pressure of the outgoing primary header necessary for securing the minimum flow rate for protecting the heat source unit as a target value ,
Based on the measured value of the terminal air conditioner inlet pressure sensor, the number control of the secondary pumps, the inverter control of the secondary pumps, and the pressure relief valve of the secondary pumps are controlled,
Based on the measurement value of the pressure sensor that detects the pressure of the outgoing water primary header, the number of the heat source units is controlled,
The number control of the secondary pump, the inverter control of the secondary pump, the pressure relief valve control of the secondary pump, the control of the control two-way valve of the communication pipe, and the number control of the heat source machine , All controlled based only on the pressure in the pipe,
After fully utilizing the lift of the primary pump for conveyance to the air conditioning load side, only the flow rate necessary for maintaining the inlet pressure of the terminal air conditioner can be adjusted by inverter control of the secondary pump.
A heat source control system characterized by that. In order to supply heat source water (cold / warm water) according to the air conditioning load, a plurality of heat source units that generate the heat source water, a plurality of primary pumps that transport the heat source water as an auxiliary device of the heat source unit, and a heat source from the heat source unit A primary water header and a secondary water header that mix water, a plurality of secondary pumps that send heat source water from the primary water header to the secondary water header, and supply of heat source water from the secondary pump Receiving air conditioning load, a two-way valve for an air conditioner provided on the outlet side of the air conditioning load, a return water header to which heat source water exchanged by the air conditioning load is returned, and between the outgoing primary header and the return water header In a closed two-pump heat source system comprising a communication pipe connecting
A control two-way valve is provided in the communication pipe;
A pressure sensor for detecting the differential pressure between the Kaemizu header and the往水primary header is provided,
A terminal air conditioner inlet pressure sensor is provided at the inlet of the air conditioning load, which is the farthest end in terms of pressure loss,
The control two-way valve is controlled with the differential pressure required to secure a minimum flow rate for protecting the heat source unit as a target value ;
Based on the measured value of the terminal air conditioner inlet pressure sensor, the number control of the secondary pumps, the inverter control of the secondary pumps, and the pressure relief valve of the secondary pumps are controlled,
Based on the measured value of the pressure sensor that detects the differential pressure between the outgoing water primary header and the return water header, the number of the heat source machines is controlled,
The number control of the secondary pump, the inverter control of the secondary pump, the pressure relief valve control of the secondary pump, the control of the control two-way valve of the communication pipe, and the number control of the heat source machine , All controlled based only on the pressure in the pipe,
After fully utilizing the lift of the primary pump for conveyance to the air conditioning load side, only the flow rate necessary for maintaining the inlet pressure of the terminal air conditioner can be adjusted by inverter control of the secondary pump.
A heat source control system characterized by In the inverter control of the secondary pump, the heat source control system according to claim 1 or 2, characterized in that instead of providing the lowest frequency setting, the control in the full range from 0 Hz. Wherein the pressure relief valve controlling the secondary pump, the heat source control system according to claim 1 or 2, wherein the secondary pump only during operation one, characterized in that control of the pressure relief valve is carried out. In the control of the control two-way valve,
When the control two-way valve is closed with all the two-way valves for the air conditioner being fully closed, the pressure of the outgoing primary header immediately before the heat source machine stops due to a drop in flow rate or the 3. The heat source control system according to claim 1, wherein the control two-way valve is controlled using a differential pressure between the primary water header and the return water header as a target value . 4. A heat source control method of a heat source system according to claim 1 or 2,
When the control two-way valve is closed with all the two-way valves for the air conditioner being fully closed, the pressure of the outgoing primary header immediately before the heat source machine stops due to a drop in flow rate or the Controlling the control two-way valve with a differential pressure between the outgoing water primary header and the return water header as a target value;
Controlling the number of secondary pumps based on the measured value of the terminal air conditioner inlet pressure sensor;
Controlling the inverter of the secondary pump based on the measured value of the terminal air conditioner inlet pressure sensor;
Controlling the pressure relief valve of the secondary pump based on the measured value of the terminal air conditioner inlet pressure sensor;
Controlling the number of the heat source units based on the pressure sensor of the outgoing water primary header or the measurement value of the pressure sensor for detecting the differential pressure between the outgoing water primary header and the returning water header;
Equipped with a,
All are controlled only based on the pipe pressure,
After fully utilizing the head of the primary pump for conveyance to the air conditioning load side, only the flow rate necessary for maintaining the terminal air conditioner inlet pressure is adjusted by inverter control of the secondary pump.
The heat source control method characterized by the above-mentioned.