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EP2394099A1 - Commande d'une sous-station de chauffage de district - Google Patents

Commande d'une sous-station de chauffage de district

Info

Publication number
EP2394099A1
EP2394099A1 EP10736098A EP10736098A EP2394099A1 EP 2394099 A1 EP2394099 A1 EP 2394099A1 EP 10736098 A EP10736098 A EP 10736098A EP 10736098 A EP10736098 A EP 10736098A EP 2394099 A1 EP2394099 A1 EP 2394099A1
Authority
EP
European Patent Office
Prior art keywords
primary
supply temperature
temperature
district heating
heat
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP10736098A
Other languages
German (de)
English (en)
Inventor
Jerker Delsing
Jan Van Deventer
Jonas Gustafsson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
D-Con
Original Assignee
D-Con
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by D-Con filed Critical D-Con
Publication of EP2394099A1 publication Critical patent/EP2394099A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
    • F24D10/00—District heating systems
    • F24D10/003—Domestic delivery stations having a heat exchanger
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
    • F24D19/00—Details
    • F24D19/10—Arrangement or mounting of control or safety devices
    • F24D19/1006—Arrangement or mounting of control or safety devices for water heating systems
    • F24D19/1009—Arrangement or mounting of control or safety devices for water heating systems for central heating
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
    • Y02B30/17—District heating
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E20/00—Combustion technologies with mitigation potential
    • Y02E20/14—Combined heat and power generation [CHP]

Definitions

  • the present invention relates to control of a district heating substation having a primary supply line for receiving, from a district heating plant, a heat carrier having a primary supply temperature, and a primary return line for returning, to the district heating plant, the heat carrier with a primary return temperature, the substation comprising a heat exchanger having a primary side connected between the primary supply line and primary return line, and a secondary side connected to a heat distribution system.
  • a CHP plant connected to a district heating network utilizes the district heating system as big heat sink for the cooling water in the power production process. This is good way of creating a win-win situation as the excess heat produced in the power production can be sold as district heating, and concurrently decreases environmental effect when less amount of primary fuel is needed.
  • ⁇ T temperature drop
  • the ⁇ T also influences the electricity production in the CHP plant.
  • the returning district heating water condensate the hot steam after the electricity producing turbines in extraction condensing CHP, a lower returning district heating temperature (higher ⁇ T) will increase steam condensation capabilities. This result in a higher pressure drop across the turbine, that hence can turn faster and produce more electric power.
  • increased ⁇ T also contributes to decrease the pump power needed in the DH network, reduces distribution losses and enables more customers to connect to the available DH network.
  • a method for controlling a district heating substation comprising storing a relationship between primary supply temperature and desired secondary supply temperature, detecting a primary supply temperature, using said relationship to determine a set point value for secondary supply temperature based on the detected primary supply temperature, and controlling the secondary supply temperature according to said set point value, by regulating the primary side flow.
  • a district heating substation comprising a memory storing a relationship between primary supply temperature and desired secondary supply temperature, a sensor for detecting a primary supply temperature, a primary side control valve for regulating a primary flow through the primary side, and a controlled connected to said sensor and arranged to determine a set point value for secondary supply temperature based on the detected primary supply temperature and said relationship, and to control the secondary supply temperature according to said set point value, by actuating the primary side control valve.
  • the present invention is based on the realization that the secondary supply temperature is not subject to any significant variations due to realistic load variations with constant primary supply temperature. Therefore, the substation control may be based on primary supply temperature without negatively affecting the temperature drop ⁇ T.
  • the primary supply temperature depends non linearly on outdoor temperature.
  • One example is when many separate heat plants are connected to the same district heating network. At low system load (high outdoor temperature) it may then be sufficient to just utilize one plant, but when the system load increases over a certain level, an additional heat plant needs to be run. This can in many cases result in a "step" or other non linearity of the primary supply temperature.
  • the control system will not be optimal, as the primary temperature changes somewhat independent from the outdoor temperature.
  • a system according to the present invention will not suffer from the same drawbacks, as the radiator supply temperature will be correlated to primary supply temperature, thus avoiding the non-linearities between primary supply temperature and outdoor temperature.
  • Another positive aspect of primary temperature based control is limitation of sudden heat load peaks during e.g. a rain shower that decreases the outdoor temperature temporarily. Using traditional outdoor temperature dependent control methods this means that the primary flow will increase, even though there is no need for that as the building has a long thermal time constant. As a result, the primary temperature drop ⁇ T will decrease. In a system according to the present invention, where the primary flow is based on primary supply temperature, this effect is avoided as the primary supply temperature is controlled externally, by the energy company.
  • the relationship between primary supply temperature and secondary supply temperature may be formed by determining, for each primary supply temperature in a set of primary supply temperatures, a secondary supply temperature that minimizes the primary return temperature for this primary supply temperature.
  • the relationship should be determined from a "steady state” analysis, i.e. a situation where the outdoor temperature and primary supply temperature are assumed to be constant.
  • the primary return temperature can be significantly decreased, and the temperature drop ⁇ T at the substation can be increased. Compared to conventional heating system control, this more optimal control leads to an increased temperature drop over the heat distribution system.
  • a conventional system typically is dimensioned as a so called 60/40 system, radiator supply temperature 6O 0 C and radiator return temperature 4O 0 C at dimensioned minimal outdoor temperature
  • a system according to this embodiment of the invention typically leads to a corresponding 75/25 system. The exact temperatures will depend on the dimensioning of the heat distribution system, i.e. number of radiators, their convection capacity, etc.
  • radiator supply temperature will result in a decreased secondary side flow
  • heat distribution system can be referred to as a "low-flow high temperature" system.
  • Such a system has a large temperature drop at each radiator, which in turn enables a large temperature drop at the primary side.
  • the secondary supply temperature that minimizes the primary return temperature for a given primary supply temperature can advantageously be determined based on a simulation model of a building heated by the district heating substation. By simulating a gradual decrease of secondary side flow rate, while maintaining a constant power consumption, a local minimum of the primary return temperature can be localized, and the corresponding secondary supply temperature may be determined.
  • the heat distribution system comprises a plurality of radiators, and a secondary side flow is controlled using thermostatic valves adapted to regulate the flow through each radiator based on a desired indoor temperature.
  • Thermostatic valves can limit the flow in the radiator system to achieve an optimal flow without any interference from a circulation pump.
  • the secondary flow control means may include a constant speed pump or a variable speed pump. In the latter case, the secondary flow is preferably held at a constant differential pressure e.g. using a constant pressure circulation pump, in order to reduce noise caused by pressure variations.
  • a variable speed pump may also be controlled in different ways.
  • the primary supply temperature information can be received from a heat meter arranged to measure the heat consumption in the substation. This eliminates the need for an additional temperature sensor.
  • the senor forms part of a sensor network connected to the substation controller, the sensor network being arranged to collect information from both the primary and secondary side of the heat exchanger to be used in the control process.
  • FIG. 1 shows a district heating substation 10 according to an embodiment of the present invention.
  • the substation comprises a heat exchanger 11 , with a primary side 12 and a secondary side 13.
  • the primary side is connected between a primary supply line 14 receiving a heat carrier such as water from a district heating plant (not shown), and a primary return line 15 for returning the heat carrier to the district heating plant.
  • a control valve 16 is provided to control the flow through the primary side of the heat exchanger.
  • the secondary side is connected to a heat distribution system 17, here comprising one or several radiators 18 connected to each other with piping 19.
  • a circulation pump 9 for example a constant speed circulation pump, is arranged to control the flow of a heat carrier in the heat distribution system. In order to limit pressure variations, the pump can be a constant relative pressure circulation pump.
  • thermostatic valves 20 can be mounted in series with the radiators 18 to further improve the indoor comfort by regulating the radiator flow, and hence also the radiator heat transfer in dependence of the temperature in the radiator surroundings.
  • the substation 10 further typically comprises a second heat exchanger with a secondary side connected to a tap water distribution system. This is not relevant for the present invention, and will not be further described.
  • the substation 10 further comprises a controller 21 , arranged to actuate the control valve.
  • a temperature sensor 22 is arranged to detect the temperature of the heat carrier in the primary supply line, and to provide a value of the detected primary supply temperature to the controller 21.
  • a feedback path 23 is arranged to provide the controller 21 with the temperature of the heat carrier in the secondary supply, i.e. the radiator supply temperature.
  • the temperature sensor 22 is here illustrated as the heat meter of the district heating system, otherwise used to measure power consumption in the substation for billing purposes.
  • the sensor may also form part of a more complex sensor network, where a plurality of sensor devices communicate using a suitable communication protocol.
  • the sensor devices can be arranged to collect information from both the primary side and a secondary side of the heat exchanger, which information can be used by the controller.
  • the communication in the sensor network can be performed using a standardized protocol, such as TCP/IP.
  • the sensor network can use Service Oriented Architecture protocols to automatically integrate data from connected devices into a sensor network control loop. It may also use wireless communication.
  • the primary supply delivers hot heat carrier to the primary side of the heat exchanger, where heat is transferred to the heat carrier circulated in the heat distribution system.
  • the primary return returns cooled heat carrier to the heat plant. After being heated the secondary side heat carrier is circulated in the heat distribution system, and is cooled off in the radiators 18 by heat convection.
  • the secondary side supply temperature, or radiator supply temperature is controlled by the controller 21 by actuating the control valve 16.
  • a radiator supply temperature set point, T rs se tpomt
  • T ps the detected primary supply temperature
  • the controller applies a feedback control, for example a negative feedback wherein a feedback temperature Trs.feedback from the feedback path 23 is subtracted from the temperature set point Trs setpoint, and the control valve 16 is actuated based on the resulting difference.
  • the relationship between primary supply temperature and radiator supply temperature can be determined in different ways. According to one approach, the relationship is established by selecting a desired radiator supply temperature (e.g. 6O 0 C) at a given outdoor temperature (e.g. -3O 0 C). Although often practical, this approach does not provide an optimal control in terms of temperature drop at the secondary side, and, more importantly, at the primary side. To achieve a higher primary side ⁇ T a low-flow high temperature system is preferred.
  • the relationship between primary supply temperature and secondary side temperature is determined by finding, for a given primary supply temperature, the radiator supply temperature that minimizes the primary return temperature.
  • Such a relationship can be determined using a simulation model as described in "Thermodynamic simulation of a detached house with district heating subcentral", by J. Gustafsson, J. van Deventer, and J. Delsing, IEEE, 2:nd annual Systems Conference, Montreal, April 2008.
  • the model simulates the main parts of a building connected to a district heating system, and includes: • Thermodynamic building with separate settings for floor, walls, roof and windows. The thermal inertia of the building, and air exchange rate are also simulated.
  • Supply information which includes, outdoor temperature, primary supply temperature, and primary pressure.
  • the simulation is performed as follows. At steady state conditions, i.e. constant outdoor temperature and primary supply temperature, the power consumption R, n , t of the radiator system is recorded. A slowly continuously decreasing radiator system flow rate ⁇ r is now simulated. To keep the power consumption at a constant level, the primary flow m p through the heat exchanger is adjusted according to
  • T ps and T pr are the primary supply and return temperatures
  • cp is the constant pressure heat capacity for water
  • Figure 2 shows curves for T pr , T r8 , TM r and m p simulated at an outdoor temperature of -10 0 C.
  • the optimal control conditions are met when the primary return temperature Tpr has a local minimum. This is easily located by d ⁇ pr determining when its time derivative, — — .equals zero. In fig. 2 this occurs at approximately 19:15.
  • Figure 3 shows a resulting control curve 31.
  • figure 3 also shows a conventional 60/40 control curve 32 for the simulated system. It is clear that the optimized control curve in this case has resulted in a higher radiator supply temperature.
  • a relationship must be determined between primary supply temperature and radiator supply temperature.
  • a relationship between outdoor temperature and primary supply temperature (curve 33 in figure 3) is used, and the resulting primary supply based control curve 34 is shown in figure 4. This control curve 34 may be applied in the controller in figure 1 , to be used in the control described above.
  • a control strategy according to this embodiment of the present invention has been compared with traditional control methods for two different supply temperature schemes. Simulations of three identical houses with three different control methods were conducted.
  • the first house (H1 ) is equipped with an optimal traditional control system with 60 0 C radiator supply temperature at an outdoor temperature of -30 0 C (curve 32 in figure 3).
  • the second house (H2) uses the optimized control curve (curve 31 in figure 3).
  • the third house (H3) uses the optimal control curve correlated to the primary supply temperature (curve 34 in fig. 4).
  • Simulation B uses a linear supply temperature scheme, shown as curve 36 in figure 6, whereas Simulation B uses a non-linear supply temperature variant, shown as curve 35 in figure 6.
  • the outdoor temperature included a daily variation term and a slow variation term.
  • the outdoor climate was identical for all simulation runs. Both simulation were run for a time period of 3 days.
  • Table Primary return temperature and primary flow rate in three different houses.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Steam Or Hot-Water Central Heating Systems (AREA)

Abstract

La présente invention porte sur un procédé et sur un système de commande d'une sous-station de chauffage de district (10) comportant une conduite d'alimentation primaire (14) destinée à recevoir, en provenance d'une installation de chauffage de district, un vecteur thermique ayant une température d'alimentation primaire, et une conduite de retour primaire (15) destinée à ramener, vers l'installation de chauffage de district, le vecteur thermique avec une température de retour primaire, la sous-station comprenant un échangeur de chaleur (11) comportant un côté primaire (12) relié entre la conduite d'alimentation primaire et la conduite de retour primaire, et un côté secondaire (13) relié à un système de distribution de chaleur. Une relation entre la température d'alimentation primaire et la température d'alimentation secondaire désirée est stockée, une valeur de point de consigne pour la température d'alimentation secondaire est déterminée sur la base d'une température d'alimentation primaire détectée, et la température d'alimentation secondaire est régulée selon ladite valeur de point de consigne, par régulation de l'écoulement côté primaire. La présente invention se fonde sur la prise de conscience que la température d'alimentation secondaire n'est pas soumise à une quelconque variation significative due à des variations de charge réalistes avec une température d'alimentation primaire constante. Par conséquent, la commande de la sous-station peut être basée sur la température d'alimentation primaire sans affecter négativement la chute de température ΔT.
EP10736098A 2009-01-30 2010-01-20 Commande d'une sous-station de chauffage de district Withdrawn EP2394099A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE0900107 2009-01-30
PCT/SE2010/050051 WO2010087759A1 (fr) 2009-01-30 2010-01-20 Commande d'une sous-station de chauffage de district

Publications (1)

Publication Number Publication Date
EP2394099A1 true EP2394099A1 (fr) 2011-12-14

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ID=42395829

Family Applications (1)

Application Number Title Priority Date Filing Date
EP10736098A Withdrawn EP2394099A1 (fr) 2009-01-30 2010-01-20 Commande d'une sous-station de chauffage de district

Country Status (2)

Country Link
EP (1) EP2394099A1 (fr)
WO (1) WO2010087759A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20210102218A (ko) * 2018-11-22 2021-08-19 스톡홀름 엑세르기 에이비 지역 난방 네트워크에서의 생산 실패 또는 불충분 동안 질량 흐름을 밸런싱하기 위한 방법 및 시스템

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE535665C2 (sv) * 2011-03-11 2012-10-30 Jan Forslund Förfarande och anläggning för reglering av inomhustemperaturen i ett utrymme
FR3012873B1 (fr) * 2013-11-04 2019-05-10 Collard & Trolart Thermique Methode et dispositif de transfert d'energie thermique en milieu urbain
GB2522025B (en) * 2014-01-09 2016-07-20 Greenfield Master Ipco Ltd Thermal Energy Network
DE102015014378A1 (de) * 2015-11-09 2017-05-11 Wilo Se Verfahren zur Regelung einer Kreiselpumpe sowie zugehöriges Pumpensystem
EP3488313B1 (fr) 2016-07-20 2023-08-30 Vito NV Réduction de la température de retour dans le chauffage urbain et d'augmentation de la température de retour de refroidissement urbain
EP3505832A1 (fr) * 2017-12-27 2019-07-03 Brunnshög Energi AB Méthode de contrôle d'un système de distribution thermique
EP3505831A1 (fr) 2017-12-27 2019-07-03 Brunnshög Energi AB Unité de commande et procédé pour commander une sortie du système de distribution locale de la chaleur ou du froid à partir d'un réseau de distribution d'énergie thermique
RU183885U1 (ru) * 2018-06-06 2018-10-08 Федеральное государственное бюджетное образовательное учреждение высшего образования "Национальный исследовательский Мордовский государственный университет им. Н.П. Огарёва" Индивидуальный тепловой пункт с мембранным насосом
EP3825614A1 (fr) * 2019-11-22 2021-05-26 E.ON Sverige AB Garantie d'un flux de fluide de transfert de chaleur dans un réseau de chauffage/refroidissement urbain
CN115289520B (zh) * 2022-06-20 2025-07-22 廊坊洁兰特智能科技有限公司 基于室内温度分离技术的换热站控制方法及系统

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19527743C2 (de) * 1995-07-28 1997-05-15 Baelz Gmbh Helmut Wärmeübertrager mit kondensat- und dampfseitiger Steuerung
DE60135582D1 (de) * 2001-05-03 2008-10-09 Matts Lindgren Verfahren und anordnung zur steuerung der temperatur des abgehenden stroms von einem wärmetauscher und messung von erzeugter hitze
SE530080C2 (sv) * 2006-05-23 2008-02-26 Nodais Ab Fjärrvärmesystem
EP1956460B1 (fr) * 2007-02-08 2008-10-29 Nordiq Göteborg AG Contrôle d'un système de chauffage basé sur la puissance de chauffage requise

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2010087759A1 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20210102218A (ko) * 2018-11-22 2021-08-19 스톡홀름 엑세르기 에이비 지역 난방 네트워크에서의 생산 실패 또는 불충분 동안 질량 흐름을 밸런싱하기 위한 방법 및 시스템
KR102754710B1 (ko) 2018-11-22 2025-01-13 스톡홀름 엑세르기 에이비 지역 난방 네트워크에서의 생산 실패 또는 불충분 동안 질량 흐름을 밸런싱하기 위한 방법 및 시스템

Also Published As

Publication number Publication date
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