JP5840466B2 - Variable flow rate control device for heat source pump - Google Patents

Description

  The present invention is a heat source facility that variably controls the flow rate of a heat medium according to a change in the air conditioning load state of a building as a variable flow rate control device of a heat source pump in an air conditioning facility, and performs primary / secondary heat source control with high energy saving effect. The present invention relates to a next-pump heat source variable flow system.

Conventionally, as a variable flow rate control device for a heat source pump in an air conditioning facility, there are various known primary and secondary pump type heat source variable flow systems that are heat source facilities that variably control the heat medium flow rate according to fluctuations in the air conditioning load state of the building. Yes.
First, the primary and secondary pump type heat source system, which forms the basic skeleton, is a heat source device (for refrigeration, cooling and heating only for cooling, for example, a cold / hot water generator using gas as a regeneration drive source, Cold water or hot water (hereinafter referred to as a heat medium) that has been frozen or heated by a vapor compression refrigeration cycle, etc.), and a heat source device, a heat source primary pump, a forward header, The primary side formed by the piping connecting the return header, the air conditioning load and the heat medium secondary pump, the forward header and the return header composed of an air conditioner that exchanges heat with the air to be temperature-controlled of the building through the heat medium through the heat exchange coil To the secondary side formed by a pipe connecting the two.

Usually, there is a bypass pipe that connects between the forward header and the return header, and the primary and secondary pump heat source system that connects the primary side and secondary side with the bypass pipe in common is common. .
On the secondary side, a two-way valve is very often used to adjust the heat exchange amount in the air conditioning load, and when the air conditioning load consisting of a large number of air conditioners becomes a partial load that is not the rated load, On the side, the two-way valve is throttled, and the heat medium sent to the air conditioning load is reduced. When the secondary pump is not set to a variable flow rate, excess heat medium flows through the bypass pipe, and the conveyance power of the heat medium is useless. .
Taking advantage of the fact that the flow rate of the secondary side heat medium is reduced by partial load, the heat medium secondary pump is changed to a variable flow rate, and the heat source primary pump variable flow rate corresponding to the variable flow rate of the heat source device is changed to the primary and secondary flow rate. It is the next pump type heat source variable flow system.
However, since the two variable flow pumps are controlled side by side in series, the flow rate matching of the two pumps is also a difficult system.

In the conventional primary / secondary pump type heat source variable flow rate system, the heat medium refrigerated or heated by the heat source device is pumped by the heat source primary pump to the forward header, and then by the heat medium secondary pump (the forward secondary header is After being exchanged with the air to be temperature-controlled by the heat exchange coil or the like, the heat medium sent to the air conditioning load is pumped to the air conditioning load via the water pipe (in some cases, through the secondary header) It is operated to return to the heat source device again via the return pipe and the return header.
When the flow rate of the heat medium conveyed by the heat source primary pump and the flow rate of the heat medium conveyed by the heat medium secondary pump are balanced, the flow rate of the bypass pipe connecting the forward header and the return header becomes zero. .

On the other hand, when the flow rate of the heat medium conveyed by the heat source primary pump is larger than the flow rate of the heat medium conveyed by the heat medium secondary pump, a flow from the forward header to the return water pipe is formed in the bypass pipe. . Conversely, when the flow rate of the heat medium conveyed by the heat medium secondary pump is larger than the flow rate of the heat medium conveyed by the heat source primary pump, a flow from the return water pipe to the forward header is formed in the bypass pipe. The
From the viewpoint of energy saving, it is desirable to eliminate the flow rate of the heat medium flowing through the bypass pipe as described above. Therefore, in the conventional primary and secondary pump heat source variable flow system, a flow meter is installed in the bypass pipe, System that measures the flow rate of the heat medium primary pump so that the bypass pipe flow rate is always measured, the measured value is input to the heat source controller, and the bypass pipe flow rate becomes zero. There is.

Thus, when performing variable control of the heat source primary pump according to the load, an expensive flow meter is installed in the bypass pipe, and the heat source primary pump rotation speed control is performed by the output signal calculated from the flow rate by the flow rate controller. This method is adopted and control is basically performed so that the flow rate of the bypass pipe is zero. However, this alone may break down an important requirement of maintaining the water supply temperature and the return water temperature of the heat medium in a predetermined temperature range.
Therefore, in order to ensure responsiveness to heat medium feed water temperature and return water temperature disturbance during control operations at startup, etc., when the return temperature of the heat medium is within a predetermined value, the bypass pipe flow rate is a predetermined “fixed value”. ”Outputs a variable flow rate control signal to the heat source primary pump so that it is not zero (as described above, but is a slight amount as the flow from the forward header to the return header in the actual preferred control). When the temperature deviates from the specified range, control to variably control the heat source primary pump so that the bypass pipe flow rate becomes a fixed value flow rate, and to increase or decrease the flow rate of the heat source primary pump based on the water supply temperature. A primary / secondary pump heat source variable flow rate system that outputs power has been proposed (see, for example, Patent Document 1).

  In another example of a conventional primary / secondary pump type heat source variable flow rate system, the bypass pipe is not equipped with a flow meter, but the temperature-controlled air and the heat medium that has been heat-exchanged by the air conditioning load are returned together. A flow meter that measures the flow rate of the heat medium in the pipe that returns to the return header as a load flow rate is provided. A technique has been proposed in which the heat source primary pump flow rate is controlled according to the proportional flow rate (see, for example, Patent Document 2).

  In addition, as a variable flow system of another type, which is a primary pump in which the heat medium secondary pump and the heat source primary pump are combined into one unit, this is an example of a primary pump type heat source variable flow system. Instead, a differential pressure gauge is installed between the forward header and the return header (in parallel with the bypass pipe), and when the two-way valve of the air conditioning load is closed, a large amount of heat medium does not flow in the bypass pipe. Thus, a technique for indirectly monitoring the bypass flow rate and controlling the primary pump flow rate (and bypass valve) by using a pressure gauge instead of a flow meter to observe the differential pressure at both ends of the bypass pipe has been proposed (for example, And Patent Document 3).

Japanese Patent No. 3,365,997 Japanese Patent No. 4,173,981 Japanese Patent No. 3,652,974

  However, in Patent Document 1, (1) in a system that is difficult to perform flow rate matching in which two pumps are arranged in series and control the variable flow rate, control based on the flow rate signal is likely to cause chasing control and control is very disturbed. Problems, (2) The problem that the flow meter for transmitting the control signal is expensive, (3) Furthermore, in order to ensure the responsiveness to the turbulence of the heat transfer water supply temperature and the return water temperature, the heat source device outlet is troublesome. It is good to create a flow from the outbound header to the return header so that the return temperature is not mixed by mixing the return water to the outbound side where the outbound temperature can be specified, but the bypass flow rate is set to a “fixed value”. However, the deviation between the actual flow rate and the set value with large fluctuations by the variable flow rate method fluctuates and the control of the heat source primary pump tends to be disturbed. (4) When the return temperature of the heat medium is within a predetermined value, a signal for performing variable control of the flow rate to the heat source primary pump so that the flow rate of the bypass pipe becomes a “fixed value” of the flow from the predetermined forward header to the return header. When the return temperature of the heat medium deviates from the predetermined range, the variable control of the heat source primary pump at the bypass pipe flow rate is stopped, and the flow rate of the heat source primary pump is increased or decreased based on the water supply temperature. By having switching control according to the case of outputting control output, there are a number of problems such as a complicated control system and a problem that the flow rate may fluctuate drastically during switching.

  Further, in Patent Document 2, (1) a flow meter that measures the flow rate of the heat medium in the pipe returning to the return header as a load flow rate is required, and the measurement is performed at the highest flow rate. (2) The heat medium flow rate measured by the flow meter is one of the heat source devices currently in operation, which is the calculation result of another unit control circuit. (3) Furthermore, although the apportioning flow rate can be obtained immediately by dividing the number of units, the flow rate changes for each system element through which the heat medium flows. In a system where the relationship with the pressure loss change is linear, quadratic, or n-th order function, and the rated absolute value is various, how is the proportional flow rate signaled to the primary pump? Is either give problems, decent considered correct problems requires complicated control logic, there are a number of problem.

Moreover, in patent document 3, instead of having a flow meter in the bypass pipe, a differential pressure gauge was provided between the forward header and the return header (in parallel with the bypass pipe), and the two-way valve of the air conditioning load was closed. At this time, the bypass valve is also controlled based on the measured value of the differential pressure gauge, and the primary pump is also controlled so that a large amount of heat medium does not flow unnecessarily through the bypass pipe. As described above, when the air-conditioning load is a partial load, the two-way valve is throttled on the secondary side and the heat medium sent to the air-conditioning load is reduced, so the surplus heat medium should flow to the bypass valve. A complicated control is performed in order to provide a bypass valve and prevent it from flowing through the bypass pipe. In this technology, it is very difficult to control both the bypass valve and the primary pump so that the surplus heat medium is zero, and if the control is not possible, the fundamental function of the bypass pipe for flowing the surplus is impaired. The flow control of the two-way valve of the air conditioning load is affected, and there is a big problem that the control on the air conditioning load side becomes unsuccessful.
As shown in the above three examples, the conventional primary / secondary pump type heat source variable flow rate system cannot achieve variable flow rate control without using expensive measuring instruments and complicated control. .

  The present invention has been made to solve such a conventional problem, and its purpose is to use a thermometer, which is an inexpensive measuring instrument originally installed at a necessary place in a heat source facility. As a primary / secondary pump type heat source variable flow system that achieves variable flow rate control of the heat source primary pump that is not affected by the control system on the secondary side and that can guarantee the water supply temperature by simply configuring cascade control. An object of the present invention is to provide a variable flow rate control device for a heat source pump.

Heat invention, which are connected a plurality of air-conditioning heat load to the load-side apparatus which is variable flow control according to the processing vital each air-conditioning load amount of heat in a plurality of air-conditioning load, in the forward header and went back header according to claim 1 A heat source pump variable flow rate control device which is a primary / secondary pump type heat source variable flow system having a side device, wherein the heat source side device is connected to the forward header which is an end of the load side device. A plurality of heat source devices connected to each other, a plurality of heat source primary pumps with inverters connected to each heat source device via primary heat source return pipes, one end of which is connected to the heat source device, and the other end the primary heat source went back conduit being connected to said went back header, between header went back the said inverter with a heat source primary pump, the primary heat source went back thermometer provided respectively, the forward f Composed of a bypass line which connects the the da went back header, and a control device which controls a flow rate of the inverter with a heat source primary pump based on the primary heat source went back temperature measurement signal from the primary heat source went back thermometer The secondary side return pipe main pipe that collects the heat medium from the plurality of air conditioning loads of the load side device and returns it to the return header is provided with a secondary side heat medium return thermometer, and the secondary side the measured value of the heat medium went back thermometer input to the control device, have rows cascade control to set sequentially based on the set value of the primary heat source went back temperature measurement value of the secondary side heat medium went back thermometer, the A heat medium maintained at a constant forward temperature is sent from the heat source side device via the forward header, and the difference between the secondary side heat medium return temperature and the forward temperature is calculated as the difference between the primary side heat source return temperature and the forward temperature. By always reducing the difference, the bypass Wherein forming a flow toward the went back header from the forward header, and wherein the flow in a large amount (rich) as compared to the heating medium amount flowing through the load-side device heating medium amount flowing through the heat source-side device.

According to a second aspect of the present invention, the variable flow control device of the heat source pump as claimed in claim 1, before Symbol controller based on said secondary side heat medium went back heat medium measured by the thermometer went back temperature (T1) The temperature value (T1) pv-Tα) obtained by subtracting a predetermined difference (Tα) during cooling or the temperature value (T1] pv + Tα) obtained by adding the predetermined difference (Tα) during heating is calculated and calculated, and the primary side heat source return temperature Cascade control that is sequentially set as a set value of (inlet temperature of the heat source primary pump with inverter), and the heat medium temperature measured by the primary side heat source return thermometer is the temperature value (T1) pv-Tα) or The flow rate control of the heat source primary pump with an inverter is performed so as to be a temperature value (T1) pv + Tα).
The invention according to claim 3 is the variable flow rate control device for the heat source pump according to claim 2 , wherein Tα is 0.2 ° C to 0.5 ° C.

According to the present invention, the variable flow rate control of the heat source primary pump can be performed only by temperature control without using an expensive control device such as a flow meter or a pressure transmitter.
According to the present invention, since the set value of the heat source inlet temperature is determined based on the return temperature on the load side, and the variable flow rate control of the heat medium is performed, a complicated wholesale control device is not required.

According to the present invention, it is possible to minimize the bypass flow rate between the return headers, and therefore it is possible to reduce useless conveyance power.
According to the present invention, since the constituent devices are the temperature measuring device, the temperature indicating controller, and the INV, the heat source can be easily updated from the constant flow device to the variable flow device at low cost.

It is explanatory drawing which shows the primary and secondary pump system heat source variable flow system 1 which concerns on 1st embodiment of this invention. It is a block diagram of the control apparatus in FIG. It is a figure which shows the relationship between the output from the temperature instruction | indication controller in FIG. 1, and a primary pump output. It is a figure which shows the operation | movement flow in FIG. It is a figure which shows how to obtain | require the heat source operation number in FIG. It is explanatory drawing shown about the case where there is no change in the secondary side going back temperature difference in FIG. 1, and the flow volume of the secondary side increased. It is a figure which shows the relationship between the output from the temperature instruction | indication controller in FIG. 6, and a primary pump output. It is explanatory drawing shown about the case where the return temperature of the secondary side in FIG. 1 rises and there is no change in the flow volume of a secondary side. It is explanatory drawing which shows the primary and secondary pump system heat source variable flow system 1 which concerns on 2nd embodiment of this invention. It is a block diagram of the control apparatus in FIG. It is a figure which shows the relationship between the output from the temperature instruction | indication controller in FIG. 9, and a primary pump output. It is a figure which shows the operation | movement flow in FIG. FIG. 10 is an explanatory diagram showing a case where there is no change in the secondary side return temperature difference in FIG. 9 and the flow rate on the secondary side increases. It is a figure which shows the relationship between the output from the temperature instruction | indication controller in FIG. 13, and a primary pump output. It is explanatory drawing shown about the case where the return temperature of the secondary side in FIG. 9 falls and there is no change in the flow volume of a secondary side.

Hereinafter, the present invention will be described based on embodiments shown in the drawings.
(First embodiment)
FIG. 1 is an explanatory diagram showing a primary / secondary pump heat source variable flow system 1 according to a first embodiment of the present invention.
The primary / secondary pump heat source variable flow rate system 1 according to the present embodiment includes a cooling heat source side device 10 (also referred to as a primary side) and a load side device 20 (also referred to as a secondary side). . In addition, when it has the refrigerator only for cooling shown as this embodiment, it becomes a single embodiment, but the heat source device of the second embodiment described later is common to the refrigerator of this embodiment, and from the outside air temperature etc. It goes without saying that the primary / secondary pump heat source variable flow rate system 1 sharing the first embodiment and the second embodiment by switching between the cooling and heating-use seasons is naturally included.

The cooling heat source side device 10 includes two refrigerators (heat source devices) 11a and 11b, primary forward pipes 12a and 12b, a first forward header 13, and two heat source primary pumps 14a and 14b with inverters. The primary heat source return pipes 15a and 15b, the return header 18 and the bypass pipe 19 are provided.
The two refrigerators (heat source devices) 11a and 11b are connected to the first forward header 13 via primary forward conduits 12a and 12b, respectively.
Two inverters with heat source primary pumps 14a and 14b are connected to the two refrigerators (heat source devices) 11a and 11b via primary heat source return pipes 15a and 15b, respectively.

The primary heat source return pipes 15 a and 15 b each having one end connected to the two refrigerators (heat source devices) 11 a and 11 b are connected to the return header 18 at the other end. In the primary heat source return pipes 15a and 15b, primary side heat source return thermometers 16a and 16b are provided between the heat source primary pumps 14a and 14b with inverter and the return header 18, respectively.
The two heat source primary pumps 14a and 14b with inverters and the primary side heat source return thermometers 16a and 16b are connected to temperature indicating controllers (control devices) 17a and 17b, respectively.
The first outgoing header 13 and the return header 18 are connected by a bypass line 19.
The heat source side apparatus 10 which is a primary side is comprised by these apparatuses and piping.

On the other hand, the load side device 20 which is the secondary side includes a first forward header 13 (common with the primary side), a second forward header 21, and three heat medium secondary pumps 22a, 22b and 22c with inverters. , 24n, secondary side forward pipeline 23, two-way valve 25a,... 25n, secondary return pipeline 26, return header 18 (Same as the primary side).
The second forward header 21 is disposed to face the first forward header 13, and three inverter-equipped heat medium secondary pumps 22 a, between the first forward header 13 and the second forward header 21. 22 b and 22 c are connected via a part of the secondary outgoing line 23.
The secondary outgoing line 23 having the first outgoing header 13 as one end is configured to transfer the heat medium from the second outgoing header 21 to the other end by the pumping force of the three heat medium secondary pumps 22a, 22b, and 22c with inverters. Are connected to a plurality of air conditioning loads 24a,.

The plurality of air conditioning loads 24a,..., 24n are connected to the secondary return pipe line 26 via two-way valves (flow rate adjusting valves) 25a,.
The secondary side return pipe line 26 having one end connected to the plurality of air conditioning loads 24a,..., 24n gathers the branch pipes connected to all the air conditioning loads and becomes a main pipe. A return thermometer 27 is provided, and the other end is connected to the return header 18. The secondary heat medium return thermometer 27 is connected to the temperature indicating controllers 17a and 17b.
The secondary side is a variable flow rate load side device that requires a constant temperature as the temperature of the heating medium introduced into the air conditioning loads 24a, ... 24n. The secondary side variable flow rate control based on the load side water supply pressure in the second forward header 21 that is the discharge of the heat medium secondary pumps 22a, 22b, and 22c with inverter will be described.

Each of the air conditioning loads 24a,..., 24n becomes a partial load at an arbitrary rate depending on the direction of the building, the personnel density, etc., and the two-way valves 25a,. Yes. The overall opening / closing degree of the two-way valve is regarded as a change in the discharge pressure of the heat medium secondary pumps 22a, 22b, 22c with inverter, and the second is the discharge of the heat medium secondary pumps 22a, 22b, 22c with inverter. The control is basically performed so that the load-side water supply pressure in the forward header 21 is constant. The measured value of the pressure gauge 29 provided in the second forward header 21 is input to an unillustrated pressure indicator adjuster and operated to control the flow rate of the heat medium secondary pumps 22a, 22b, 22c with inverter.
The secondary side return pipe 26 is provided with a secondary side heat medium return flow meter 28 at a place where the branch pipes connected to all the air conditioning loads are gathered to become a main pipe, and a flow rate instruction not shown in the figure is shown. An input operation is performed on the regulator, and the number of heat medium secondary pumps 22a, 22b, and 22c with inverters is controlled.
The secondary heat medium return flowmeter 28 is naturally not an essential element in the present invention.

In the present embodiment, the temperature indicating regulators 17a and 17b are, for example, as shown in FIG. 2, the temperature (PV) measured by the secondary heat medium return thermometer 27 that measures the return temperature of the secondary heat medium. And a calculation unit A for setting the set values (SP) of the primary side heat source return thermometers 16a and 16b based on the temperature (PV) measured by the secondary side heat medium return thermometer 27.
The calculation unit A calculates the set value (SP) of the primary side heat source return thermometers 16a and 16b from the temperature (PV) measured by the secondary side heat medium return thermometer 27 to an arbitrary temperature Tα (for example, 0.5 ° C. ) Is reduced to (T1) pv−Tα).
The adjustment unit B has a measurement value (TR1) such that the measurement values (TR1] and TR2] of the primary side heat source return thermometers 16a and 16b become the value (T1] pv−Tα) calculated by the calculation unit A. ], TR2]) and the calculated set value (T1] pv−Tα), the inverters that control the rotational speeds of the two heat source primary pumps 14a and 14b with inverters have two heat source primarys with inverters. A command for controlling the number of revolutions of the pumps 14a and 14b is output to perform variable flow rate control.

Here, how to determine Tα in the present embodiment will be described.
The closer Tα is to 0 ° C, the smaller the bypass flow rate (when Tα is 0 ° C, the steady-state bypass flow rate is 0), and the conveyance power of the heat source primary pumps 14a, 14b with inverter is suppressed. A value close to 0 ° C is desirable.
However, the flow rate on the primary side (heat source side device 10) is larger than the flow rate on the secondary side (load side device 20) in order to ensure responsiveness to the return water flow rate and the return water temperature turbulence returning from the air conditioning load ( By being rich, the water supply temperature to the secondary side (load side device 20) is secured, so it cannot be 0 ° C. For this guarantee, there is also the responsiveness of the whole system as a heat source device, but the temperature resolution of the primary side heat source return thermometers 16a and 16b and the secondary side heat medium return thermometer 27, which are measuring devices, and temperature indication adjustment There are also time constants and offsets of instrumentation systems that combine the inverters 17a and 17b, signal transmission, and the operation device, and the value of Tα is preferably 0.2 ° C. or more, for example.

  For example, when the return temperature difference on the secondary side (load side device 20) is 7 ° C. (forward 7 ° C.−return 14 ° C.), assuming that Tα = 0.5 ° C., the primary side (heat source side device 10) goes back. Since the return temperature difference is 6.5 ° C. (outward 7 ° C.−return 13.5 ° C.), the flow rate ratio between the secondary side (load side device 20) and the primary side (heat source side device 10) is the secondary side return trip. Temperature difference ÷ primary side return temperature difference = (14 ℃ -7 ℃) ÷ (13.5 ℃ -7 ℃) = 7 ℃ ÷ 6.5 ℃ = 1.08, secondary side (load side device 20) If the flow rate is 100%, the flow rate on the primary side (heat source side device 10) is 108%, that is, 8% of the flow rate on the secondary side (load side device 20) is bypass flow rate (forward header → return header) Occurs as.

The value of Tα is applied to the primary / secondary pump heat source variable flow rate system 1 according to the present embodiment depending on the temperature difference between the return temperature to the secondary side (load side device 20) and the return temperature and the temperature measurement deviation. Decide on site.
For example, the bypass flow rate is 0.5 ° C. (Tα) when the temperature difference between the return temperature to the secondary side (load side device 20) and the return temperature is 7 ° C. (forward temperature 7 ° C.−return temperature 14 ° C.). ÷ 7 ° C (temperature difference) ≒ 7%, 0 ° when the temperature difference between the return temperature to the secondary side (load side device 20) and the return temperature is 10 ° C (forward temperature 7 ° C-return temperature 17 ° C). 5 [deg.] C. (T [alpha]) / 10 [deg.] C. (temperature difference) = 5%, and even if temperature deviation is taken into consideration, the temperature difference is generally 10% or less.

On the other hand, the range of Tα is the return temperature difference of 0 ° C. <Tα <secondary side (load side device 20).
For example, when the secondary side (load side device 20) has an outgoing temperature of 7 ° C. and the secondary side (load side device 20) has a return temperature of 14 ° C., 14 ° C.−7 ° C. = 7 ° C., and the upper limit of Tα is 7 ° C. It becomes ℃.
Further, in the case of Tα ≦ 0 ° C., the difference in the return temperature on the primary side (heat source side device 10) becomes larger than the difference in the return temperature on the secondary side (load side device 20). 20) The flow rate increases. For this reason, since it becomes rich, the flow of the bypass pipe becomes the return header → the forward header, and the water supply temperature on the secondary side (load side device 20) becomes higher than 7 ° C.

FIG. 3 shows inverter outputs of the heat source primary pumps 14a and 14b with two inverters based on the adjustment unit B. FIG.
Further, in the present embodiment, the flow rate corresponding to a predetermined difference Tα for obtaining the set values of the temperature indicating controllers 17a and 17b of the inlet temperatures of the two heat source primary pumps 14a and 14b with the inverter from the return temperature of the secondary side heat medium is obtained. The bypass pipe 19 between the first forward header 13 and the return header 18 is flowed so that the flow rate of the heat source side device 10 is rich by a predetermined difference Tα compared to the flow rate of the secondary side device 20. Can be.

In the primary / secondary pump heat source variable flow rate system 1 according to the present embodiment configured as described above, first, initial pump frequency setting of the two heat source primary pumps 14a and 14b with inverters is performed by any of the following methods. (Set the maximum frequency and minimum frequency).
(1) Calculate the pressure loss of the system of the heat source primary pumps 14a and 14b with inverter from the pressure loss of the piping and the equipment pressure loss of the refrigerator, and the pump operating frequency that becomes the rated flow rate of the refrigerator from the PQ diagram of the pump (Maximum frequency) and the pump operation frequency (minimum frequency) that is the minimum flow rate required for the refrigerator.
(2) A flow meter that can be installed temporarily (for example, an ultrasonic flow meter) is installed during trial operation, and the pump operating frequency (maximum frequency) that is the rated flow rate of the refrigerator and the minimum flow rate that is required for the refrigerator (minimum) Frequency)) is set.

Next, as in the case of a normal primary / secondary pump heat source variable flow rate system, two or more refrigerators (heat source devices) 11a and 11b are used in order to cope with the load fluctuations of the building throughout the year. As shown in FIG. 4, in step S <b> 1, the heat source operation number calculation according to the air conditioning load heat amount is performed, and operation commands for the heat source primary pumps 14 a and 14 b with inverters are output.
This operation number calculation does not fall below the preset minimum flow rate of the heat medium so that the heat source device such as a refrigerator can be operated without any trouble, and the flow rate at the time of start-up at the time of additional operation of the operation number For example, as shown in FIG. 5, the number of operating heat source devices is based on the flow rate of the secondary side (load side device 20) and the magnitude of the load heat amount. To be judged. This unit control is less frequent in one day.
Next, for example, when two refrigerators (heat source devices) 11a and 11b are determined, the two heat source primary pumps 14a and 14b with inverters are started (step S2).
Next, a predetermined difference Tα is set (step S3).

Next, the primary side refrigerator return temperature (TR1] sp = T1] pv−Tα, TR2] sp = T1] pv−Tα) is calculated by the calculation unit A of the temperature indicating controllers 17a and 17b (step S4). .
Next, in the adjustment part B, the measurement values (TR1] sp, TR2] sp) of the primary side heat source return thermometers 16a, 16b become values (T1] pv−Tα) calculated by the calculation part A. The rotational speeds of the two heat source primary pumps 14a, 14b with inverter are controlled (step S5).

Next, the operation | movement according to the load change in the primary and secondary pump type heat source variable flow system 1 which concerns on this embodiment is demonstrated.
FIG. 6 shows the case where there is no change in the return-side temperature difference on the secondary side and the flow rate on the secondary side increases.
In this example, a case where the heat source device 11a has a rated cooling capacity of 700RT and the heat source device 11b has a rated cooling capacity of 800RT will be described.
FIG. 6A shows an initial state of the primary / secondary pump heat source variable flow rate system 1 according to the present embodiment.

  The load on the secondary side is 750 RT. At this time, the going-out temperature of the cold water is 7 ° C., the return temperature of the cold water is 14 ° C., and the flow rate of the cold water in the secondary return line 26 is 5,400 L / min. Further, the two refrigerators (heat source devices) 11a and 11b generate cold water having an outlet temperature of 7 ° C. Therefore, in the heat source device 11a, 350 RT of 50% of the rated cooling capacity 700 RT, in the heat source device 11b, It is operating at 400RT, which is 50% of the rated cooling capacity of 800RT. At this time, the heat source primary pump 14a with an inverter is controlled to send 2,720 L / min of cold water, and the heat source primary pump 14b with an inverter is controlled to send 3,110 L / min of cold water. Therefore, the flow rate of cold water is 5,830 L / min.

The cold water of 7 ° C. sent to the first forward header 13 is subjected to an air conditioning load from the second forward header 21 via the secondary forward conduit 23 by the three heat medium secondary pumps 22a, 22b, 22c with inverter. 24 a, 24 b,... 24 n, and 5,400 L / min of cold water is returned via the secondary return pipe 26 via the two-way valves (flow rate adjusting valves) 25 a,. Returned to
Further, 430 L / min of 7 ° C. cold water is supplied from the first forward header 13 to the return header 18 via the bypass line 19.

The return temperature (PV) of cold water measured by the secondary heat medium return thermometer 27 is 14 ° C.
Therefore, the inlet temperature of the heat source primary pumps 14a, 14b with inverter is 14 ° C.−Tα (0.5 ° C.) = 13.5 ° C.
FIG. 6B shows a state in which the load on the secondary side fluctuates from the state in FIG. 6A, the secondary side return temperature difference does not change, and the flow rate on the secondary side increases.
Here, the load on the secondary side is increased from 750 RT to 788 RT, the return flow rate of cold water in the secondary return line 26 is changed from 5,400 L / min to 5,670 L / min, and the bypass flow rate of 7 ° C. cold water is increased. It decreased from 430 L / min to 160 L / min.

The temperature in the return header 18 by the primary side heat source return thermometers 16a and 16b rises from 13.5 ° C. to 13.8 ° C.
Therefore, as shown in FIG. 6C, the temperature indicating controllers 17a and 17b have a temperature in the return header 18 by the primary heat source return thermometers 16a and 16b of 14 ° C.−Tα (0.5 ° C.) = Until the temperature reaches 13.5 ° C., a command to increase the rotational speeds of the two heat source primary pumps 14a, 14b with inverters is output to the two heat source primary pumps 14a, 14b with inverters.

As a result, the heat source primary pump 14a with an inverter increases the rotational speed and pumps 2,853 L / min of return cold water to the heat source device 11a, and the heat source device 11a performs 368RT to generate 7 ° C. cold water. The heat source primary pump 14b with an inverter increases the rotational speed and pumps 3,256 L / min of return cold water to the heat source device 11b, and the heat source device 11b performs 420 RT to generate 7 ° C. cold water.
Further, the bypass flow rate of cold water at 7 ° C. is increased from 160 L / min to 439 L / min.
This control is performed until the temperature in the return header 18 by the primary side heat source return thermometers 16a and 16b reaches 14 ° C.−Tα (0.5 ° C.) = 13.5 ° C.

FIG. 7 shows an inverter output example of the heat source primary pumps 14a and 14b with two inverters in FIG.
Fig.7 (a) shows the inverter output example of the heat source primary pumps 14a and 14b with two inverters in Fig.6 (a).
Here, it is assumed that the inverter outputs of the heat source primary pumps 14a and 14b with two inverters are balanced at 60%.
Further, assuming that the maximum frequency of the inverter outputs of the heat source primary pumps 14a and 14b with two inverters is 100%, the minimum frequency is 50%, and the proportional band is 5 ° C., the cold water return temperature and the heat source primary pump 14a with two inverters , 14b are as shown in FIG.

FIG.7 (b) shows the inverter output example of the heat source primary pumps 14a and 14b with two inverters in FIG.6 (b).
As the flow rate on the secondary side (load side) increases, the mixing ratio of the bypass pipe 19 changes, and the return temperature of the cold water rises.
Even if a deviation of SP = 14 ° C.−Tα (0.5 ° C.) = 13.5 ° C. (13.5 ° C. → 13.8 ° C.) occurs, the inverters of the heat source primary pumps 14a and 14b with two inverters The output increases from 60% to 63%.

FIG.7 (c) shows the inverter output example of the heat source primary pumps 14a and 14b with two inverters in FIG.6 (c).
It is assumed that the inverter outputs of the heat source primary pumps 14a and 14b with two inverters are 76.7% and PV = 13.5 ° C. and balanced (due to changes in the flow rate and heat quantity on the water side).
Since the inverter output of the heat source primary pumps 14a and 14b with two inverters is balanced with SP = PV = 13.5 ° C. in this water side state, 0.3 ° C. (63% −60% = 3%).

FIG. 8 shows a case where the return temperature on the secondary side rises and there is no change in the flow rate on the secondary side.
In this example, a case where the heat source device 11a has a rated cooling capacity of 700RT and the heat source device 11b has a rated cooling capacity of 800RT will be described.
FIG. 8A shows an initial state of the primary / secondary pump heat source variable flow rate system 1 according to the present embodiment, similarly to FIG. 6A. Although details are the same as in FIG. 6A, the return temperature on the secondary side (load side) is 14 ° C., so the temperature settings (SP) of the heat source primary pumps 14a and 14b with two inverters are set. The value is 13.5 ° C.
FIG. 8B shows a state where the load on the secondary side fluctuates from the state of FIG. 8A, the return temperature on the secondary side rises, and the flow rate on the secondary side does not change.

Here, the load on the secondary side increases from 750 RT to 857 RT, and the measured value of the secondary return thermometer 27 increases from 14 ° C. to 15 ° C.
Thus, since there is no change in the flow rate on the secondary side (load side) and the return temperature changes from 14 ° C. to 15 ° C., the temperature setting (SP) values of the heat source primary pumps 14a, 14b with two inverters are: Change from 13.5 ° C to 14.5 ° C.
At this time, cold water of 7 ° C. flows from the first forward header 13 through the bypass pipe 19 into the return header 18 and mixes with the return water of 15 ° C. to become 14.4 ° C. return water, {(7 ° C. × 430 L / min) + (15 ° C. × 5,400 L / min)} ÷ (430 L / min + 5,400 L / min) = 14.4 ° C., return header by primary side heat source return thermometers 16a, 16b The temperature in 18 increases from 13.5 ° C. to 14.4 ° C.

Therefore, as shown in FIG. 8C, the temperature indicating controllers 17a and 17b have a temperature in the return header 18 by the primary heat source return thermometers 16a and 16b of 15 ° C.−Tα (0.5 ° C.) = Until the temperature reaches 14.5 ° C., a command to lower the rotational speeds of the two heat source primary pumps 14a, 14b with inverters is output to the two heat source primary pumps 14a, 14b with inverters.
As a result, the heat source primary pump 14a with an inverter reduces the rotation speed and pumps 2,688 L / min of return cold water to the heat source device 11a, and the heat source device 11a performs 400 RT to generate 7 ° C. cold water. The heat source primary pump 14b with an inverter lowers the rotational speed and pumps 3071 L / min of return cold water to the heat source device 11b, and the heat source device 11b performs 457RT to generate 7 ° C. cold water.

Further, the bypass flow rate of cold water at 7 ° C. is reduced from 430 L / min to 359 L / min.
This control is performed until the temperature in the return header 18 by the primary side heat source return thermometers 16a and 16b reaches 15 ° C.−Tα (0.5 ° C.) = 14.5 ° C.
As described above, in the primary / secondary pump heat source variable flow rate system 1 according to the present embodiment, the temperature value (T1) obtained by subtracting the predetermined difference (Tα) based on the return temperature (PV value) of the load-side cold water. pv−Tα) is input as a cascade control to the setting value (SP) of the temperature indicating regulators 17a and 17b of the inlet temperature of the heat source primary pumps 14a and 14b with inverter, and the inlet temperature of the heat source primary pumps 14a and 14b with inverter is calculated. The variable flow rate control can be performed by controlling the rotation speed of the heat source primary pumps 14a, 14b with inverter based on the output values of the temperature indicating controllers 17a, 17b.

Further, the flow rate corresponding to a predetermined difference Tα ° C. for obtaining the set value (SP) of the temperature indicating controllers 17a, 17b of the inlet temperatures of the two heat source primary pumps 14a, 14b from the inverter-side cold water return temperature (PV value). Can be made to flow in a rich manner by a flow rate corresponding to a predetermined difference Tα ° C. on the primary side as compared to the secondary side, by flowing the bypass conduit 19 between the first forward header 13 and the return header 18.
In addition, even if it fluctuates during the transition period, the temperature is controlled so that the low-temperature cold water at the refrigerator outlet temperature flows into the return header 18 by a predetermined difference Δt ° C. by the bypass line 19, and according to the load heat amount at that time The flow rates of the heat source primary pumps 14a and 14b with inverter can be controlled so as to converge only by the outputs of the temperature indication controllers 17a and 17b for the inlet temperature of the heat source primary pumps 14a and 14b with inverter.

Further, the measured value PV of the return temperature of the load-side chilled water, the predetermined difference Tα ° C., the bypass chilled water in the bypass pipe 19 and the set value (SP) of the inlet temperature of the heat source primary pumps 14a, 14b with inverter and the load-side chilled return water. With the planned harmony of the mixing temperature (PV-Tα) with the above, the flow rate of the bypass cold water flowing through the bypass pipe line 19 in a steady state converges to secure a flow rate for a predetermined difference Tα that does not depend on the amount of load heat.
Therefore, the position of the proportional band of the output from the temperature indicating regulators 17a and 17b of the inlet temperature of the heat source primary pumps 14a and 14b with the inverter is automatically and appropriately determined according to the total heat transfer amount as shown in FIG. Shift.
Moreover, about the temperature compensation to the secondary side (load side apparatus 20), it is ensured by the flow volume of the primary side (heat source side apparatus 10) becoming large (rich).

Moreover, the measurement point required for control is the secondary side heat medium return thermometer 27 that measures the return temperature of the secondary side (load side device 20), and the primary that measures the return temperature of the primary side (heat source side device 10). Since only two of the side heat source return thermometers 16a and 16b are required, the number of observation points required for the control is small, and the control is performed with an inexpensive and high-resolution measuring instrument.
In addition, the simple cascade control that changes the setting according to the return temperature on the secondary side does not require complicated conditions such as switching without any trouble to operate constantly during the operation of the system. Heat of the forward temperature that flows to the return side through the bypass pipe only by controlling the flow rate of the heat source primary pumps 14a, 14b with inverters so that the temperature of the inlets of the two heat source primary pumps 14a, 14b with inverters is always reduced to Tα from the temperature. Since the control is performed so that the mixing in the return header 18 with the medium can be automatically performed, as a whole, when the return temperature on the secondary side becomes low, the number of rotations of the heat source primary pumps 14a and 14b with two inverters is reduced to restrict the flow rate. When the return temperature on the secondary side rises, the control is performed to increase the flow rate by increasing the rotational speed of the heat source primary pumps 14a and 14b with two inverters. And which, together with the heat source device constant control of the outlet temperature is an object of the present invention, the design temperature difference of the heat medium, which is also controlled to approach the set point went back temperature of the secondary side.

As described above, in the primary / secondary pump type heat source variable flow rate system 1 according to the present embodiment, the temperature of the two heat source primary pumps 14a and 14b with inverter is changed by the change of the return temperature of the secondary side (load side device 20). The number of rotations of the heat source primary pumps 14a, 14b with two inverters so that the setting (SP) value changes and the deviation from the inlet temperature (refrigerator inlet temperature) of the heat source primary pumps 14a, 14b with two inverters becomes zero. Can always be controlled.
Further, the temperature indicating controllers 17a and 17b can be controlled simply by automatically changing the setting according to the secondary return temperature, and are complicated and require complicated special conditions for special control logic and correction as in the prior art. The problem of requiring control is solved.

In the present embodiment, the heat source side device 10 is configured by the two refrigerators (heat source devices) 11a and 11b and the two heat source primary pumps 14a and 14b with an inverter. However, the present invention is not limited to this, and three units are provided. You may comprise the heat source side apparatus 10 with the above heat source device and the heat source primary pump with an inverter.
Moreover, in this embodiment, the load side apparatus 20 is used as the secondary side variable flow rate control based on the load side water supply pressure in the second forward header which is discharge of the heat medium secondary pump, for example. Forward header 21, three inverter-equipped heat medium secondary pumps 22a, 22b, 22c, a plurality of air-conditioning loads 24a,... 24n, a secondary-side forward conduit 23, and a two-way valve (flow adjustment valve) 25a,... 25n, the secondary return pipe 26, the pressure gauge 29 provided in the second forward header 21, and the secondary heat medium return flow meter 28 are described. The present invention is not limited to this, and as described above, the secondary side is a load-side device with a variable flow rate that requires a constant temperature for the heating medium introduced into the air conditioning loads 24a,. As long as there is a heat return thermometer 27, what kind of control is the system? It may be configured.

(Second embodiment)
FIG. 9 is an explanatory diagram showing a primary / secondary pump heat source variable flow rate system 1A according to the second embodiment of the present invention.
A primary / secondary pump heat source variable flow rate system 1A according to the present embodiment includes a heating heat source side device 10A (also referred to as a primary side) and a load side device 20A (also referred to as a secondary side). . In addition, when it has a hot water generator dedicated to heating shown as this embodiment, it becomes a single embodiment, but the heat source device of the first embodiment described above is common with the hot water generator of this embodiment, the outside air temperature It goes without saying that the primary / secondary pump type heat source variable flow rate system 1 that shares the first embodiment and the second embodiment by switching between the cooling mode and the heating mode derived from the above is naturally included.
Heat source side device 10A for heating includes two hot water generators (heat source devices, for example, devices capable of generating hot water such as absorption chiller / heaters, boilers, and air-cooled heat pump chillers) 11Aa, 11Ab, and primary forward pipes Path 12Aa, 12bA, first forward header 13A, two inverter-equipped heat source primary pumps 14Aa, 14Ab, primary heat source return pipes 15Aa, 15Ab, return header 18A, and bypass pipe 19A. .

The two hot water generators (heat source devices) 11Aa and 11Ab are connected to the first forward header 13A via primary forward conduits 12Aa and 12Ab, respectively.
Two heat source primary pumps 14Aa and 14Ab with inverters are connected to the two hot water generators (heat source devices) 11Aa and 11Ab via primary heat source return pipes 15Aa and 15Ab, respectively.
The primary heat source return pipes 15Aa and 15Ab, which are connected at one end to the heat source devices 11Aa and 11Ab, respectively, are connected at the other end to the header 18A. Primary heat source return pipes 15Aa and 15Ab are provided with primary side heat source return thermometers 16Aa and 16Ab between the heat source primary pumps 14Aa and 14Ab with inverters and the return header 18A, respectively.

The two heat source primary pumps 14Aa and 14Ab with inverters and the primary side heat source return thermometers 16Aa and 16Ab are connected to temperature indicating controllers (control devices) 17Aa and 17Ab, respectively.
The first forward header 13A and the return header 18A are connected by a bypass line 19A.
These devices and pipes constitute a heat source side device 10A that is the primary side.

On the other hand, the load side device 20A that is the secondary side includes a first forward header 13A (common with the primary side), a second forward header 21A, and three heat medium secondary pumps 22Aa, 22Ab, and 22Ac with inverters. , 24An, secondary side forward pipeline 23A, two-way valve 25Aa,... 25An, secondary return pipeline 26A, and return header 18A. (Same as the primary side).
The second forward header 21A is arranged to face the first forward header 13A, and between the first forward header 13A and the second forward header 21A, three heat medium secondary pumps 22Aa with inverters, 22Ab and 22Ac are connected via a part of secondary side outgoing pipe line 23A.
The secondary-side outgoing line 23A having the first outgoing header 13A as one end is configured to transfer the heat medium from the second outgoing header 21 to the other end by the pumping force of the three heating medium secondary pumps 22Aa, 22Ab, and 22Ac. Are connected to a plurality of air conditioning loads 24Aa,.

The plurality of air conditioning loads 24Aa,... 24An are connected to the secondary return line 26A via two-way valves (flow rate adjusting valves) 25Aa,.
The secondary return pipe 26A, one end of which is connected to the plurality of air conditioning loads 24Aa,... 24An, gathers the branch pipes connected to all the air conditioning loads and becomes the main pipe. A return thermometer 27A is provided, and the other end is connected to the return header 18A. The secondary heat medium return thermometer 27A is connected to the temperature indicating controllers 17Aa and 17Ab.
The secondary side is a load side device with a variable flow rate that requires a constant temperature for the heating medium temperature introduced into the air conditioning loads 24Aa,... 24An. The secondary side variable flow rate control based on the load side water supply pressure in the second forward header 21A, which is the discharge of the heat medium secondary pumps 22Aa, 22Ab, 22Ac with an inverter, will be described.

Each of the air conditioning loads 24Aa,..., 24An becomes a partial load at an arbitrary rate depending on the direction of the building and the personnel density, and the two-way valves 25Aa,. Yes. The overall opening / closing degree of the two-way valve is regarded as a change in the discharge pressure of the heat medium secondary pumps 22Aa, 22Ab, and 22Ac with an inverter, and the load-side water supply pressure in the second forward header that is the discharge of the pump is made constant. Control based on the control to be performed. The measurement value of the pressure gauge 29A provided in the second forward header 21A is input to a pressure indicator / regulator (not shown) and calculated to control the flow rate of the heat medium secondary pumps 22Aa, 22Ab, 22Ac with inverter.
The secondary side return pipe 26A is provided with a secondary side heat medium return flow meter 28A at a place where the branch pipes connected to all the air conditioning loads are gathered to become the main pipe, and a flow rate instruction not shown in the figure is shown. An input operation is performed to the regulator, and the number of heat medium secondary pumps 22Aa, 22Ab, and 22Ac with inverters is controlled.
The secondary side heat medium return flowmeter 28A is naturally not an essential element in the present invention.

In the present embodiment, the temperature indicating regulators 17Aa and 17Ab are, for example, as shown in FIG. 10, the temperature (PV) measured by the secondary side heat medium return thermometer 27A that measures the return temperature of the secondary side heat medium. And a calculation unit Aa for setting the set values (SP) of the primary heat source return thermometers 16Aa and 16Ab based on the temperature (PV) measured by the secondary heat medium return thermometer 27A.
The calculation unit Aa calculates the set value (SP) of the primary side heat source return thermometers 16Aa and 16Ab from the temperature (PV) measured by the secondary side heat medium return thermometer 27A to an arbitrary temperature Tα (for example, 0.5 ° C. ) Is added to the value (T1) pv + Tα).
The adjustment unit Ba has the measurement values (TR1), the measurement values (TR1), TR2]) of the primary side heat source return thermometers 16Aa, 16Ab to be the values (T1) pv + Tα) calculated by the calculation unit Aa. TR2]) and the calculated set value (T1) pv + Tα) according to the temperature deviation between the two heat source primary pumps 14Aa and 14Ab with two inverters, and the two heat source primary pumps 14Aa and 14Ab with inverters. A command to control the number of rotations is output and variable flow rate control is performed.

Here, how to determine Tα in the present embodiment will be described.
The closer Tα is to 0 ° C, the smaller the bypass flow rate (when Tα is 0 ° C, the steady-state bypass flow rate is 0), and the conveyance power of the heat source primary pumps 14Aa, 14Ab with inverter is suppressed. A value close to 0 ° C is desirable.
However, the flow rate on the primary side (the heat source side device 10A) is larger than the flow rate on the secondary side (the load side device 20A) in order to ensure responsiveness to the return water flow rate and the return water temperature disturbance returned from the air conditioning load ( By being rich, the water supply temperature to the secondary side (load side device 20A) is secured, so it cannot be 0 ° C. For this guarantee, there is also the responsiveness of the whole system as a heat source device, but the temperature resolution of the primary side heat source return thermometers 16Aa, 16Ab and the secondary side heat medium return thermometer 27A, which are measuring devices, and temperature indication adjustment There are also time constants and offsets of the instrumentation system that combines the inverters 17Aa, 17Ab, signal transmission, and operation devices, and the value of Tα is preferably 0.2 ° C. or more, for example.

  For example, when the return temperature difference on the secondary side (load side device 20A) is 7 ° C. (45 ° C. minus 38 ° C. return), assuming that Tα = 0.5 ° C., the return on the primary side (heat source side device 10A) Since the return temperature difference is 6.5 ° C. (45 ° C.-return 38.5 ° C.), the flow rate ratio between the secondary side (load side device 20A) and the primary side (heat source side device 10A) is secondary side return. Temperature difference ÷ primary side return temperature difference = (45 ° C-38 ° C) ÷ (45 ° C-38.5 ° C) = 7 ° C ÷ 6.5 ° C = 1.08, secondary side (load side device 20A) If the flow rate is 100%, the flow rate on the primary side (heat source side device 10A) is 108%, that is, the flow rate on the secondary side (load side device 20A) is 8% of the bypass flow rate (forward header → return header). Occurs as.

The value of Tα is applied to the primary / secondary pump heat source variable flow system 1A according to the present embodiment, depending on the temperature difference between the return temperature to the secondary side (load side device 20A) and the return temperature and the temperature measurement deviation. Decide on site.
For example, the bypass flow rate is 0.5 ° C. (Tα) when the temperature difference between the return temperature to the secondary side (load side device 20A) and the return temperature is 7 ° C. (forward temperature 45 ° C.−return temperature 38 ° C.). ÷ 7 ° C (temperature difference) ≒ 7%, 0 ° when the temperature difference between the return temperature to the secondary side (load side device 20A) and the return temperature is 10 ° C (forward temperature 45 ° C-return temperature 35 ° C). 5 [deg.] C. (T [alpha]) / 10 [deg.] C. (temperature difference) = 5%, and even if temperature deviation is taken into consideration, the temperature difference is generally 10% or less.

On the other hand, the range of Tα is the return temperature difference of 0 ° C. <Tα <secondary side (load side device 20A).
For example, if T1] pv + Tα is a premise, when the return temperature of the secondary side (load side device 20A) is 45 ° C. and the return temperature of the secondary side (load side device 20A) is 38 ° C., 45 ° C.−38 ° C. = 7 ° C., and the upper limit of Tα is 7 ° C.
Further, when Tα ≦ 0 ° C., the difference in the return temperature on the primary side (the heat source side device 10A) becomes larger than the difference in the return temperature on the secondary side (the load side device 20A). The flow rate of 20A) increases. For this reason, since it becomes rich, the flow of the bypass pipe becomes the return header → the forward header, and the water supply temperature on the secondary side (load side device 20) becomes lower than 45 ° C.

FIG. 11 shows the inverter outputs of the heat source primary pumps 14Aa and 14Ab with two inverters based on the adjusting unit Ba.
In this embodiment, the flow rate corresponding to a predetermined difference Tα for obtaining the set values of the temperature indicating controllers 17Aa and 17Ab of the inlet temperatures of the two heat source primary pumps 14Aa and 14Ab with the inverter from the return temperature of the secondary side heat medium is obtained. The bypass pipe 19A between the first outgoing header 13A and the return header 18A is made to flow, and the flow rate of the heat source side device 10A is rich by a predetermined difference Tα compared to the flow rate of the secondary side device 20A. Can be.

In the primary / secondary pump type heat source variable flow rate system 1A according to the present embodiment configured as described above, first, initial pump frequency setting of the two heat source primary pumps 14Aa and 14Ab with inverters is performed by any of the following methods. (Set the maximum frequency and minimum frequency).
(1) Calculate the pressure loss of the system of the heat source primary pumps 14Aa, 14Ab with inverter from the pressure loss of the piping and the equipment pressure loss of the refrigerator, and the pump operating frequency that becomes the rated flow rate of the refrigerator from the PQ diagram of the pump (Maximum frequency) and the pump operation frequency (minimum frequency) that is the minimum flow rate required for the refrigerator.
(2) A flow meter that can be installed temporarily (for example, an ultrasonic flow meter) is installed during trial operation, and the pump operating frequency (maximum frequency) that is the rated flow rate of the refrigerator and the minimum flow rate that is required for the refrigerator (minimum) Frequency)) is set.

Next, as in the case of a normal primary / secondary pump type heat source variable flow rate system, two or more refrigerators (heat source devices) 11Aa and 11Ab are used in order to cope with fluctuations in the building load throughout the year. As shown in FIG. 12, in step S1, a heat source operation number calculation corresponding to the air conditioning load heat amount is performed, and operation commands for the heat source primary pumps 14Aa and 14Ab with inverters are output.
This operation number calculation does not fall below the predetermined minimum flow rate of the heat medium so that the heat source device such as a hot water generator can be operated without malfunction, and at the time of start-up at the time of additional operation of the operation number For example, as shown in FIG. 5, the number of operating heat source devices is based on the flow rate on the secondary side (load side device 20A) and the magnitude of the load heat amount while considering to avoid fluctuations in the flow rate and water supply temperature. Is judged. This unit control is less frequent in one day.
Next, for example, when two hot water generators (heat source devices) 11Aa and 11Ab are determined, the two heat source primary pumps 14Aa and 14Ab with inverters are started (step S2).
Next, a predetermined difference Tα is set (step S3).

Next, the primary side refrigerator return temperature (TR1] sp = T1] pv + Tα, TR2] sp = T1] pv + Tα) is calculated by the calculation unit Aa of the temperature indicating controllers 17Aa and 17Ab (step S4).
Next, in the adjusting unit Ba, the measured values (TR1] sp, TR2] sp of the primary side heat source return thermometers 16Aa, 16Ab are set to 2 (T1] pv + Tα) calculated by the calculating unit Aa. The number of revolutions of the heat source primary pumps 14Aa, 14Ab with two inverters is controlled (step S5).

Next, the operation | movement according to the load change in the primary and secondary pump system heat source variable flow system 1A which concerns on this embodiment is demonstrated.
FIG. 13 shows a case where there is no change in the return-side temperature difference on the secondary side and the flow rate on the secondary side increases.
In this example, the case where the heat source device 11Aa has a rated heating capacity of 700RT and the heat source device 11Ab has a rated heating capacity of 800RT will be described.
FIG. 13A shows an initial state of the primary / secondary pump heat source variable flow rate system 1A according to the present embodiment.

  The load on the secondary side is 750 RT. At this time, the forward temperature of the hot water is 45 ° C., the return temperature of the hot water is 38 ° C., and the flow rate of the cold water in the secondary return pipe line 26 A is 5,400 L / min. Further, the two hot water generators (heat source devices) 11Aa and 11Ab generate hot water having an outlet temperature of 45 ° C. Therefore, in the heat source device 11Aa, 350 RT of 50% of the rated heating capacity 700 RT, and in the heat source device 11Ab It is operating at 400RT, 50% of the rated heating capacity of 800RT. At this time, the heat source primary pump 14Aa with an inverter is controlled to send 2,720 L / min of hot water, and the heat source primary pump 14Ab with an inverter is controlled to send 3,110 L / min of hot water. Accordingly, the flow rate of the hot water is 5,830 L / min.

The 45 ° C. warm water sent to the first forward header 13A is subjected to an air conditioning load from the second forward header 21A via the secondary forward pipeline 23A by the three heat medium secondary pumps 22Aa, 22Ab, 22Ac with inverters. 24Aa, 24Ab,... 24An are pumped, and 5,400 L / min of hot water is returned to the return header 18A via the two-way valves (flow rate adjusting valves) 25Aa,. Returned to
Further, 430 L / min of 45 ° C. hot water is supplied from the first outgoing header 13A to the return header 18A via the bypass line 19A.

The return temperature (PV) of hot water measured by the secondary side heat medium return thermometer 27A is 38 ° C.
Accordingly, the inlet temperature of the heat source primary pumps 14Aa, 14Ab with inverter is 38 ° C. + Tα (0.5 ° C.) = 38.5 ° C.
FIG. 13B shows a state in which the load on the secondary side fluctuates from the state of FIG. 13A, the secondary side return temperature difference does not change, and the flow rate on the secondary side increases.
Here, the load on the secondary side is increased from 750 RT to 788 RT, the return flow rate of the warm water in the secondary return line 26A is changed from 5,400 L / min to 5,670 L / min, and the bypass flow rate of 45 ° C. hot water is It decreased from 430 L / min to 160 L / min.

The temperature in the return header 18A by the primary side heat source return thermometers 16Aa and 16Ab is lowered from 38.8 ° C. to 38.2 ° C.
Therefore, as shown in FIG. 13C, the temperature indicating controllers 17Aa and 17Ab have a temperature in the return header 18A by the primary side heat source return thermometers 16Aa and 16Ab of 38 ° C. + Tα (0.5 ° C.) = 38. Until the temperature reaches 5 ° C., commands to increase the rotational speeds of the two heat source primary pumps 14Aa and 14Ab with inverters are output to the two heat source primary pumps 14Aa and 14Ab with inverters.

As a result, the heat source primary pump 14Aa with an inverter increases the rotational speed and pumps 2,853 L / min of return hot water to the heat source device 11Aa, and the heat source device 11Aa performs 368RT to generate 45 ° C. hot water. The heat source primary pump 14Ab with an inverter increases the rotational speed and pumps 3,256 L / min of return hot water to the heat source device 11Ab. The heat source device 11Ab performs 420 RT to generate 45 ° C. hot water.
Further, the bypass flow rate of 45 ° C. warm water is increased from 160 L / min to 439 L / min.
This control is performed until the temperature in the return header 18A by the primary side heat source return thermometers 16Aa and 16Ab reaches 38 ° C. + Tα (0.5 ° C.) = 38.5 ° C.

FIG. 14 shows an inverter output example of the heat source primary pumps 14Aa and 14Ab with two inverters in FIG.
Fig.14 (a) shows the inverter output example of heat source primary pump 14Aa, 14Ab with two inverters in Fig.13 (a).
Here, it is assumed that the inverter outputs of the heat source primary pumps 14Aa and 14Ab with two inverters are balanced at 60%.
Further, assuming that the maximum frequency of the inverter output of the heat source primary pumps 14Aa and 14Ab with two inverters is 100%, the minimum frequency is 50%, and the proportional band is 5 ° C., the cold water return temperature and the heat source primary pump 14Aa with two inverters , 14Ab inverter output is as shown in FIG.

FIG.14 (b) shows the inverter output example of heat source primary pump 14Aa, 14Ab with two inverters in FIG.13 (b).
Due to the increase in the flow rate on the secondary side (load side), the mixing ratio of the bypass pipe 19A changes, and the return temperature of the hot water rises.
Even if a deviation (38.5 ° C. → 38.2 ° C.) from SP = 38 ° C. + Tα (0.5 ° C.) occurs, the inverter outputs of the two heat source primary pumps 14Aa, 14Ab with inverters are reduced from 60% to 63%. To%.

FIG.14 (c) shows the inverter output example of heat source primary pump 14Aa, 14Ab with two inverters in FIG.13 (c).
It is assumed that the inverter outputs of the heat source primary pumps 14Aa and 14Ab with two inverters are 63% and PV = 38.5 ° C. to be balanced (due to changes in the flow rate and heat quantity on the water side).
Since the inverter output of the heat source primary pumps 14Aa, 14Ab with two inverters is balanced with SP = PV = 38.5 ° C. in this water side state, 0.3 ° C. (63% −60% = 3%).

FIG. 15 shows a case where the return temperature on the secondary side decreases and the flow rate on the secondary side does not change.
In this example, the case where the heat source device 11Aa has a rated cooling capacity of 700RT and the heat source device 11Ab has a rated cooling capacity of 800RT will be described.
FIG. 15A shows an initial state of the primary / secondary pump heat source variable flow rate system 1A according to the present embodiment, similarly to FIG. 13A. Although details are the same as in FIG. 13A, the description will be omitted, but since the return temperature on the secondary side (load side) is 38 ° C., the temperature setting (SP) of the heat source primary pumps 14Aa and 14Ab with two inverters The value is 38.5 ° C.
FIG. 15B shows a state where the load on the secondary side fluctuates from the state of FIG. 15A, the return temperature on the secondary side rises, and the flow rate on the secondary side does not change.

Here, the secondary load increases from 750 RT to 857 RT, and the measured value of the secondary return thermometer 27A decreases from 38 ° C. to 37 ° C.
Thus, since there is no change in the flow rate on the secondary side (load side device 20A) and the return temperature changes from 38 ° C. to 37 ° C., the temperature setting (SP) values of the heat source primary pumps 14Aa, 14Ab with two inverters Change from 38.5 ° C to 37.5 ° C.
At this time, 45 ° C. warm water flows from the first forward header 13A through the bypass line 19A into the return header 18A and mixes with 37 ° C. return water to become 37.6 ° C. return water, {(45 ° C. X430 L / min) + (37 ° C. × 5,400 L / min)} ÷ (430 L / min + 5,400 L / min) = 37.6 ° C., return headers by primary side heat source return thermometers 16Aa, 16Ab The temperature in 18 increases from 38.5 ° C to 37.6 ° C.

Therefore, as shown in FIG. 15C, the temperature indicating controllers 17Aa and 17Ab have a temperature in the return header 18A of the primary heat source return thermometers 16Aa and 16Ab of 37 ° C. + Tα (0.5 ° C.) = 37. Until the temperature reaches 5 ° C., commands to lower the rotational speeds of the two heat source primary pumps 14Aa and 14Ab with inverters are output to the two heat source primary pumps 14Aa and 14Ab with inverters.
As a result, the heat source primary pump 14Aa with an inverter lowers the rotational speed and pumps 2,688 L / min of return cold water to the heat source device 11Aa, and the heat source device 11Aa performs 400 RT to generate 45 ° C. hot water. The heat source primary pump 14Ab with an inverter lowers the rotation speed and pumps 3071 L / min of return hot water to the heat source device 11Ab. The heat source device 11Ab performs 457RT to generate 45 ° C. hot water.

Moreover, the bypass flow rate of 45 degreeC warm water is reduced from 430 L / min to 359 L / min.
This control is performed until the temperature in the return header 18A by the primary heat source return thermometers 16Aa and 16Ab reaches 37 ° C. + Tα (0.5 ° C.) = 37.5 ° C.
As described above, in the primary / secondary pump heat source variable flow rate system 1A according to the present embodiment, the temperature value (T1) obtained by adding a predetermined difference (Tα) based on the return temperature (PV value) of the load-side hot water. pv + Tα) is input as a cascade control to the set value (SP) of the inlet temperature indicator regulators 17Aa, 17Ab of the heat source primary pumps 14Aa, 14Ab with inverter, and the temperature indication of the inlet temperature of the heat source primary pumps 14Aa, 14Ab with inverter Based on the output values of the regulators 17Aa and 17Ab, the number of revolutions of the heat source primary pumps 14Aa and 14Ab with inverter can be controlled to perform variable flow rate control.

Further, the flow rate corresponding to a predetermined difference Tα ° C. for obtaining the set values (SP) of the temperature indicating controllers 17Aa and 17Ab of the inlet temperatures of the heat source primary pumps 14Aa and 14Ab with two inverters from the return temperature (PV value) of the load-side hot water. Is allowed to flow in a rich manner by a flow rate corresponding to a predetermined difference Tα ° C. compared to the secondary side, by flowing the bypass pipe 19A between the first forward header 13A and the return header 18A.
In addition, even if it fluctuates during the transition period, the temperature is controlled so that the hot water of the hot water generator flows into the return header by a predetermined difference Δt ° C. by the bypass line 19A, and an inverter is provided according to the load heat amount at that time The flow rates of the heat source primary pumps 14Aa and 14Ab can be controlled so as to converge only by the outputs of the temperature indication controllers 17Aa and 17Ab for the inlet temperature of the heat source primary pumps 14Aa and 14Ab with inverter.

Further, the measured value PV of the return temperature of the load side cold water, the predetermined difference Tα ° C., the bypass hot water in the bypass line 19A and the load side return hot water of the set value (SP) of the inlet temperature of the heat source primary pumps 14Aa, 14Ab with inverters With the planned harmony of the mixing temperature (PV + Tα), the flow of the bypass hot water flowing through the bypass pipe line in a steady state converges to secure a flow rate for a predetermined difference Tα that does not depend on the load heat amount.
Therefore, the position of the proportional band of the output from the temperature indicating regulators 17Aa and 17Ab of the inlet temperature of the heat source primary pumps 14Aa and 14Ab with inverters is automatically and appropriately determined according to the total heat transfer amount as shown in FIG. Shift.
Moreover, about the temperature compensation to the secondary side (load side), it is ensured by the flow volume of the primary side (heat source side apparatus 10A) becoming large (rich).

Moreover, the measurement point required for control is the secondary side heat medium return thermometer 27A that measures the return temperature of the secondary side (load side device 20A), and the primary that measures the return temperature of the primary side (heat source side device 10A). Since only two of the side heat source return thermometers 16Aa and 16Ab are required, the number of observation points required for the control is small, and the control is performed with an inexpensive and high-resolution measuring instrument.
In addition, the simple cascade control that changes the setting according to the return temperature on the secondary side does not require complicated conditions such as switching without any trouble to operate constantly during the operation of the system. A heat medium with a forward temperature that flows into the return side through the bypass pipe just by controlling the flow rate of the heat source primary pump with inverter so that the temperature of the primary heat source pump 14Aa and 14Ab with two inverters is always reduced to Tα from the temperature. Since the control is performed so that the mixing in the return header 18A can be automatically performed, as a whole, when the return temperature on the secondary side becomes low, the flow rates obtained by increasing the rotation speeds of the heat source primary pumps 14Aa and 14Ab with two inverters are increased. When the return temperature on the side rises, control is performed to limit the flow rate by lowering the rotational speed of the two heat source primary pumps 14Aa and 14Ab with inverters. Cage, together with constant control of the heat source unit outlet temperature is an object of the present invention, the design temperature difference of the heat medium, which is also controlled to approach to the design value went back temperature of the secondary side.

As described above, in the primary / secondary pump heat source variable flow rate system 1A according to the present embodiment, the temperature of the two inverter-equipped heat source primary pumps 14Aa and 14Ab is determined by the change in the return temperature of the secondary side (load side device 20A). The number of revolutions of the heat source primary pumps 14Aa, 14Ab with two inverters so that the setting (SP) value changes and the deviation from the inlet temperature (refrigerator inlet temperature) of the heat source primary pumps 14Aa, 14Ab with two inverters becomes zero. Can always be controlled.
In addition, the temperature indicating controllers 17Aa and 17Ab can be controlled simply by automatically changing the setting based on the secondary return temperature, and are complicated and require complicated special conditions for special control logic and correction as in the past. The problem of requiring control is solved.

In the present embodiment, the two hot water generators (heat source devices) 11Aa and 11Ab and the two heat source primary pumps 14Aa and 14Ab with inverters constitute the heat source side device 10A, but the present invention is not limited to this. The heat source side device 10 </ b> A may be configured by a heat source device of more than one unit and a heat source primary pump with an inverter.
Moreover, in this embodiment, the load side apparatus 20A is used as the secondary side variable flow rate control based on the load side water supply pressure in the second forward header that is the discharge of the heat medium secondary pump, for example. Forward header 21A, three inverter-equipped heat medium secondary pumps 22Aa, 22Ab, 22Ac, a plurality of air conditioning loads 24Aa,... 24An, a secondary-side forward conduit 23A, and a two-way valve (flow control valve) 25Aa,... 25An, the secondary side return conduit 26A, the pressure gauge 29A provided in the second forward header 21A, and the secondary side heat medium return flow meter 28A have been described. The present invention is not limited to this. As described above, the secondary side is a load side device with a variable flow rate that requires a constant temperature for the heating medium introduced into the air conditioning loads 24Aa,. Even heat transfer thermometer 27A If, the system may be configured in any control.

1,1A Primary / secondary pump type heat source variable flow system 10, 10A Heat source side devices 11a, 11b Refrigerator (heat source device)
11Aa, 11Ab Hot water generator (heat source device)
12a, 12b, 12Aa, 12Ab Primary outgoing pipes 13, 13A First outgoing heads 14a, 14b, 14Aa, 14Ab Heat source primary pumps with inverters 15a, 15b, 15Aa, 15Ab Primary heat source return pipes 16a, 16b, 16Aa, 16Ab Primary heat source return thermometers 17a, 17b, 17Aa, 17Ab Temperature indicating controller (control device)
18, 18A Return header 19, 19A Bypass line 20, 20A Load side device 21, 21A Second forward header 22a, 22b, 22c, 22Aa, 22Ab, 22Ac Heat medium secondary pump with inverter 24a, ... 24n, 24Aa, ... 24An Air-conditioning load 23, 23A Secondary side outgoing pipe 25a, ... 25n, 25Aa, ... 25An Two-way valve (flow control valve)
26, 26A Secondary side return pipes 27, 27A Secondary side heat medium return thermometer A, Aa calculation unit B, Bb adjustment unit

Claims (3)

To the load-side apparatus which is variable flow control in accordance with a plurality of air-conditioning heat load to the plurality of air conditioning load in processing vital each air heat load, primary and secondary having a heat source-side device connected with the forward header and went back header A heat source pump variable flow rate control device that is a pump type heat source variable flow rate system,
The heat source side device is:
A plurality of heat source devices connected to the forward header which is an end of the load side device via a primary forward conduit;
A plurality of inverter-equipped heat source primary pumps connected via primary heat source return pipes corresponding to the respective heat source devices;
Primary heat source return pipes, each having one end connected to the heat source device and the other end connected to the return header, are respectively provided between the heat source primary pump with inverter and the return header. A thermometer,
A bypass line connecting the forward header and the return header;
A control device that controls the flow rate of the heat source primary pump with an inverter based on a measurement signal of the primary side heat source return temperature from the primary side heat source return thermometer ;
The secondary side return pipe main pipe that collects the heat medium from the plurality of air conditioning loads of the load side device and returns it to the return header is provided with a secondary side heat medium return thermometer,
Cascade control for inputting the measured value of the secondary side heat medium return thermometer to the control device and sequentially setting the set value of the primary side heat source return temperature based on the measured value of the secondary side heat medium return thermometer. There line,
A heat medium maintained at a constant forward temperature is sent from the heat source side device via a forward header, and from the difference between the secondary side heat medium return temperature and the forward temperature, the primary side heat source return temperature and the forward temperature By always reducing the difference between the two, the flow from the forward header to the return header is formed in the bypass pipe, and the amount of heat medium flowing through the heat source side device is compared with the amount of heat medium flowing through the load side device. A variable flow rate control device for a heat source pump, which is a primary / secondary pump type heat source variable flow rate system, characterized by flowing a large amount (rich) . Based on the heat medium return temperature (T1) measured by the secondary-side heat medium return thermometer, the control device reduces a predetermined difference (Tα) during cooling to a temperature value (T1) pv−Tα) or during heating. Calculate and calculate a temperature value (T1) pv + Tα) obtained by adding a predetermined difference (Tα), and perform cascade control to sequentially set as a set value of the primary side heat source return temperature (inlet temperature of the heat source primary pump with the inverter),
The flow rate control of the heat source primary pump with an inverter is performed so that the heat medium temperature measured by the primary side heat source return thermometer becomes the temperature value (T1] pv−Tα) or the temperature value (T1] pv + Tα). The variable flow rate control device for a heat source pump which is the primary / secondary pump type heat source variable flow rate system according to claim 1 . The variable flow rate control device for a heat source pump as a primary / secondary pump type heat source variable flow rate system according to claim 2, wherein the predetermined difference (Tα) is 0.2 ° C to 0.5 ° C.

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