JP4909381B2 - District heat supply system - Google Patents

Description

  The present invention relates to a district heat supply system configured by connecting a heat supply plant having a primary pump and a heat source facility of a heat medium and a plurality of heat demand destinations via a heat medium circulation pipe.

  In recent years, in areas where each group of buildings such as commercial facilities and condominiums is installed, instead of installing individual heat source equipment for air conditioning and hot water such as refrigerators and boilers for each building, the area including these buildings As a heat source facility for the whole, a regional heat supply system that installs a heat supply plant in a specific place and supplies a heat medium such as cold water or hot water from the heat supply plant to the heat demand destination of each building is attracting attention. Yes.

  As a conventional district heat supply system of this type, for example, as shown in FIGS. 5 and 6, a heat supply plant 1 includes a heat source facility 2 and a pump 3 having a necessary head of the farthest end heat demand destination C. 1-pump district heat supply system installed in the plant (see, for example, Patent Documents 1 and 2), although not particularly shown, a heat pump, a primary pump responsible for the necessary head around the heat source and the need for each heat consumer A two-pump district heat supply system is known in which a plurality of secondary pumps (or one secondary pump that matches the maximum required head of the heat demand destination) are installed in a heat supply plant. .

Japanese Patent Laid-Open No. 9-210413 JP 2001-153381 A

  However, in the above-described conventional one-pump type district heat supply system, the heat demand destination A or B near the heat supply plant 1 is operated at the same pressure as the farthest heat demand destination C. However, there is a problem that the conveyance power cannot be reduced and the operation efficiency cannot be increased.

  On the other hand, the conventional two-pump type district heat supply system described above has a problem that it is difficult to reduce the conveyance power because it is necessary to always operate the primary pump and the secondary pump. In addition, when a secondary pump is installed for each heat demand destination, there is a problem that construction costs and maintenance costs cannot be reduced. Furthermore, since it is necessary to secure the operation flow rate through the bypass pipe for releasing the heat medium below the lower limit value of the operation flow rate of the secondary pump, the heat medium exceeding the necessary flow rate is transported as a result, and the transport power can be reduced. There were also problems such as difficulties.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a district heat supply system that can reduce transportation power and reduce construction costs and maintenance costs. .

  In order to achieve the above object, the present invention is such that a heat supply plant having a primary pump and a heat source facility of a heat medium and a plurality of heat demand destinations are connected via a heat medium circulation pipe having a return pipe and a return pipe. A district heat supply system configured, the farthest heat demand destination downstream from the heat demand destination in the vicinity where the required head from the heat supply plant is minimized and the farthest heat demand destination from the heat supply plant A substation is provided further upstream, and the substation is provided with a secondary pump installed on the forward piping of the heat medium circulation piping, and the primary pump is a heat demand destination upstream of the substation. The secondary pump is provided with a necessary head to the farthest heat demand destination.

  And the district heat supply system which concerns on this invention provides the secondary bypass pipe provided so that the said secondary pump may be bypassed, and the on-off valve installed on this secondary bypass pipe, from the said secondary pump When the heat supply flow rate of a part or all of the downstream heat demand destination exceeds a predetermined value, or when the differential pressure between the forward piping in the substation and the return piping is below a predetermined value, or When the pressure is equal to or lower than a predetermined value, the control for closing the on-off valve and operating the secondary pump, and the heat supply flow rate at a part or all of the heat demand destination downstream from the secondary pump is equal to or lower than the predetermined value. When the differential pressure between the forward pipe and the return pipe in the substation exceeds a predetermined value, or when the pressure of the forward pipe exceeds a predetermined value, the on-off valve is opened and the two Next pump And a controller for the control to locked.

  Moreover, the district heat supply system according to the present invention may always operate the secondary pump.

  Furthermore, the district heat supply system according to the present invention includes a pressure of the forward pipe, a differential pressure between the pressure of the forward pipe and the pressure of the return pipe, a part of a flow rate of a heat demand destination downstream from the secondary pump, or A control device is provided for controlling the number of operating secondary pumps and / or shifting control based on at least one of the information.

  ADVANTAGE OF THE INVENTION According to this invention, the district heat supply system which can reduce a conveyance power and can reduce a construction cost and a maintenance management cost can be provided.

It is a distribution diagram showing a district heat supply system concerning an embodiment of the invention. It is a pressure diagram of the district heat supply system concerning an embodiment of the invention. It is explanatory drawing which shows the control method of the district heat supply system which concerns on embodiment of this invention. It is a systematic diagram which shows the modification of the district heat supply system which concerns on embodiment of this invention. It is a systematic diagram which shows a prior art example. It is a pressure diagram of a prior art example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a system diagram showing a district heat supply system according to an embodiment of the present invention. This district heat supply system includes a heat supply plant 10 and a plurality of heat demand destinations A, B, C, and D as a heat medium. It is configured to be connected via a circulation pipe 20. The heat supply plant 10 includes primary pumps 11a and 11b and heat source facilities 12a and 12b, and a substation 30, in which two units are installed in parallel. The heat medium circulation pipe 20 includes a first forward pipe 21 and a first return pipe 22 disposed between the heat demand destinations C and D far from the heat supply plant 10, and primary pumps 11a and 11b and a heat source facility 12a. , 12b and the second forward piping 23 and the second piping 23 disposed between the heat supply destinations A and B in the vicinity of the heat supply plant 10 including the heat demand destination A where the required head from the heat supply plant 10 is minimized. And 2 return pipes 24.

  Further, in the heat supply plant 10, suction of the discharge side pipes 14 of the discharge primary pumps 11 a and 11 b and the heat source equipment 12 a and 12 b from the branch position P of the first forward pipe 21 and the second forward pipe 23 to the heat source equipment side. A primary bypass pipe 16 that connects the side pipe 15 is provided. A differential pressure bypass valve 17 is provided on the primary bypass pipe 16, and the differential pressure bypass valve 17 returns to the forward pipe side pressure (PT0) of the bypass pipe 16 by the operation of the primary pumps 11a and 11b. It is controlled so as to be opened when the differential pressure of the pipe side pressure (PT3) becomes equal to or higher than the upper limit value.

  The substation 30 is provided on the downstream side of the nearby heat demand destinations A and B and on the upstream side of the farthest heat demand destination C where the required head from the heat supply plant 10 is maximized. Secondary pumps 33a and 33b installed in parallel, a secondary bypass pipe 32 provided so as to bypass the secondary pumps 33a and 33b, and an on-off valve 31 installed on the secondary bypass pipe 32 Yes. As shown in FIG. 2, the primary pumps 11 a and 11 b have a necessary head to the heat demand destinations A and B upstream from the substation 30, and the secondary pumps 33 a and 33 b reach the farthest heat demand destination C. It has the necessary head.

  Further, the substation 30 is provided with a control device (not shown). As shown in FIG. 3, this control device has a heat downstream from the secondary pump including the farthest heat demand destination C. When the heat supply flow rate to a part or all of the demand destinations exceeds a predetermined value, or when the differential pressure between the forward pipe 21 and the return pipe 22 in the substation 30 is equal to or lower than the predetermined value, or the pressure of the forward pipe 21 is When it is less than the predetermined value, the on-off valve 31 is closed and the secondary pumps 33a and 33b are operated. At this time, the secondary pumps 33a and 33b control the number of units and / or shift control based on the pressure (PT1) of the first forward pipe 21 and the pressure (PT2) of the first return pipe 22 or the flow rates of the heat demand destinations C and D. Preferably it is done.

  In addition, the control device is configured so that the heat supply flow rate to some or all of the heat demand destinations downstream from the secondary pump including the farthest heat demand destination C is equal to or less than a predetermined value, or in the substation 30 When the differential pressure between the forward pipe 21 and the return pipe 22 exceeds a predetermined value, or when the pressure of the forward pipe (21) exceeds a predetermined value, the on-off valve 31 is opened and the secondary pumps 33a and 33b are stopped. Then, the heat medium is circulated between the heat supply plant 10 and each of the heat demand destinations A, B, C, and D by the primary pumps 11a and 11b.

  Note that the on / off valve 31 does not have to be provided in the substation 30. In this case, the secondary pumps 33a and 33b are always operated, but the pressure (PT1) of the first forward pipe 21 and the first Number control based on information on at least one of the differential pressure between the pressure of the forward piping 21 (PT1) and the pressure of the first return piping 22 (PT2) and the flow rate of the heat demand destinations C and D It is preferable that shift control is performed. Although not shown, a bypass pipe for releasing the heat medium is provided so as to bypass the secondary pumps 33a and 33b, and a secondary device is provided by providing a pressure relief device (for example, an orifice) on the bypass pipe. It is preferable to protect the pumps 33a and 33b during low flow operation.

  As described above, according to the district heat supply system according to the above-described embodiment, the heat supply is supplied to the heat demand destinations A and B near the heat supply plant 10 by the primary pumps 11a and 11b attached to the heat source devices 12a and 12b. The remote heat demand destinations C and D are configured to supply the heat medium by the secondary pumps 33a and 33b of the substation 30, so that each heat demand destination A, B, C and D is necessary. Operation according to the head can be performed. Therefore, the conveyance power can be reduced and the operation efficiency can be increased.

  Further, when the secondary pumps 33a and 33b are provided with a number control device and / or a transmission, the number of units and / or the shift control can be performed by the heat medium supply pressure or the flow rate of the heat demand destination, so that the conveyance power can be further increased. Reduction is possible.

  Further, when the on-off valve 31 is provided, when the heat medium can be supplied to each of the demand destinations A, B, C, D only by operating the primary pumps 11a, 11b, the secondary pumps 33a, 33b are stopped. By opening the on-off valve 31, further reduction of the conveyance power is possible. Further, since it is not necessary to install a secondary pump for each heat demand destination in order to reduce the conveyance power, it is possible to reduce construction costs and maintenance costs.

  In the above-described embodiment, the substation 30 is provided in the heat supply plant 10, but this is merely an example. For example, as shown in FIG. It may be installed on the medium circulation pipe 20.

  Further, the substation 30 is located downstream of the heat demand destination A in the vicinity where the required head from the heat supply plant 10 is minimized and upstream from the farthest heat demand destination C where the required head from the heat supply plant is maximized. If so, it may be installed upstream of the heat demand destination B or downstream of the heat demand destination D. When the substation 30 is installed on the upstream side of the heat demand destination B, the primary pumps 11a and 11b have a necessary head to the heat demand destination A on the upstream side of the substation 30, and the substation 30 has the heat demand destination. When installed on the downstream side of D, the primary pumps 11 a and 11 b preferably have a necessary head to the heat demand destination D upstream of the substation 30.

  Furthermore, in the above-described embodiment, two secondary pumps 33a and 33b are installed. However, this is merely an example, and for example, one or three or more secondary pumps may be installed.

  Moreover, it goes without saying that the number of primary pumps 11a, 11b can be changed in various ways, for example, by installing one or more primary pumps 11a, 11b or upstream of the heat source equipment. Nor.

DESCRIPTION OF SYMBOLS 10 Heat supply plant 11a, 11b Primary pump 12a, 12b Heat source equipment 14 Upstream piping 15 Downstream piping 16 Primary bypass piping 17 Differential pressure bypass valve 20 Heat medium circulation piping 21 First forward piping 22 First return piping 30 Substation 31 On-off valve 32 Secondary bypass pipe 33a, 33b Secondary pump A, B, C, D

Claims (3)

A district heat supply system configured by connecting a heat supply plant having a primary pump and heat source equipment of a heat medium and a plurality of heat demand destinations via a heat medium circulation pipe having a forward pipe and a return pipe,
A substation is provided downstream from a nearby heat demand destination where the required head from the heat supply plant is minimized and upstream from a farthest heat demand destination where the necessary head from the heat supply plant is maximum, The substation is provided with a secondary pump installed on the outgoing pipe of the heat medium circulation pipe, and the primary pump has a necessary head to a heat demand destination upstream of the substation, and the secondary pump Has the necessary head to the farthest heat demand destination ,
A secondary bypass pipe provided so as to bypass the secondary pump, and an on-off valve installed on the secondary bypass pipe, and a part or all of the heat demand destination downstream of the secondary pump When the heat supply flow rate exceeds a predetermined value, or when the differential pressure between the forward piping and the return piping in the substation is equal to or lower than the predetermined value, or when the pressure of the forward piping is equal to or lower than the predetermined value, the on-off valve And controlling the operation of the secondary pump and a part or all of the heat supply flow downstream of the secondary pump at a predetermined value or less, or an outgoing pipe in the substation A control device that performs control to open the on-off valve and stop the secondary pump when the differential pressure of the return pipe exceeds a predetermined value or when the pressure of the forward pipe exceeds a predetermined value; It has District heating system characterized and. District heating system as claimed in claim 1, Ru is always operated with the secondary pump. Based on information on at least one of the pressure of the forward piping, the pressure difference between the pressure of the forward piping and the pressure of the return piping, and part or all of the flow rate of the heat demand destination downstream from the secondary pump. , district heating system according to claim 1 that have a number of operating control and or shift control for controlling device of the secondary pump.

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