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District heating in case of power failure

Lauenburg, Patrick LU ; Johansson, P. -O. and Wollerstrand, Janusz LU (2010) In Applied Energy 87(4). p.1176-1186
Abstract
Power failures in combination with harsh weather conditions during recent years have led to an increased focus on a safe energy supply to our society. Many vital functions are dependent on electricity; e.g., lighting, telephony, medical equipment, lifts, alarm systems, payment, pumps for town's water and, perhaps the most critical of all. heating systems. In Sweden. district heating (DH) is the most common type of heating for buildings in town centres. Therefore, it is of great interest to investigate what happens in DH systems during a power failure. The present study shows that, by maintaining the DH production as well as the operation of the DH network, possibilities to supply connected buildings with space heat are surprisingly good.... (More)
Power failures in combination with harsh weather conditions during recent years have led to an increased focus on a safe energy supply to our society. Many vital functions are dependent on electricity; e.g., lighting, telephony, medical equipment, lifts, alarm systems, payment, pumps for town's water and, perhaps the most critical of all. heating systems. In Sweden. district heating (DH) is the most common type of heating for buildings in town centres. Therefore, it is of great interest to investigate what happens in DH systems during a power failure. The present study shows that, by maintaining the DH production as well as the operation of the DH network, possibilities to supply connected buildings with space heat are surprisingly good. This is due to the fact that natural circulation will most often take place in radiator systems. In Sweden, and in many other countries, so-called indirect connection (heat supply across heat exchangers) of DH substations is applied. If a DH network operation can be maintained during a power failure, DH water will continue to pass the radiator system's heat exchanger (HEX), provided that the control valve does not close. The radiator circulation pump will stop, causing the radiator water to attain a relatively high temperature in the HEX, which promotes a natural circulation in the hydronic heating system, due to an increased water density differential at different temperatures. Several field tests and computer simulations have been performed and have displayed that almost all buildings can achieve a space heat supply corresponding to 40-80% of the amount prior to the interruption. A sufficient heat load in the DH network can be vital in certain cases: e.g., for 'island-operation' of an electric power plant to be performed during a power failure. Furthermore, for many combined heat and power stations, a requirement involves that the DH network continues to provide a heat sink when no other cooling is available. Based on the findings presented herein, a set of recommendations have been set up to provide advice to, among others, DH utilities and owners of customer buildings. (C) 2009 Elsevier Ltd. All rights reserved. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Natural circulation, Space heating, District heating, Power failure, Island-operation
in
Applied Energy
volume
87
issue
4
pages
1176 - 1186
publisher
Elsevier
external identifiers
  • wos:000274506500011
  • scopus:73149083956
ISSN
1872-9118
DOI
10.1016/j.apenergy.2009.08.018
language
English
LU publication?
yes
id
fb9c7eb5-9c3d-4908-ab62-24bf441442a9 (old id 1568995)
date added to LUP
2010-03-17 10:12:17
date last changed
2018-06-24 04:27:39
@article{fb9c7eb5-9c3d-4908-ab62-24bf441442a9,
  abstract     = {Power failures in combination with harsh weather conditions during recent years have led to an increased focus on a safe energy supply to our society. Many vital functions are dependent on electricity; e.g., lighting, telephony, medical equipment, lifts, alarm systems, payment, pumps for town's water and, perhaps the most critical of all. heating systems. In Sweden. district heating (DH) is the most common type of heating for buildings in town centres. Therefore, it is of great interest to investigate what happens in DH systems during a power failure. The present study shows that, by maintaining the DH production as well as the operation of the DH network, possibilities to supply connected buildings with space heat are surprisingly good. This is due to the fact that natural circulation will most often take place in radiator systems. In Sweden, and in many other countries, so-called indirect connection (heat supply across heat exchangers) of DH substations is applied. If a DH network operation can be maintained during a power failure, DH water will continue to pass the radiator system's heat exchanger (HEX), provided that the control valve does not close. The radiator circulation pump will stop, causing the radiator water to attain a relatively high temperature in the HEX, which promotes a natural circulation in the hydronic heating system, due to an increased water density differential at different temperatures. Several field tests and computer simulations have been performed and have displayed that almost all buildings can achieve a space heat supply corresponding to 40-80% of the amount prior to the interruption. A sufficient heat load in the DH network can be vital in certain cases: e.g., for 'island-operation' of an electric power plant to be performed during a power failure. Furthermore, for many combined heat and power stations, a requirement involves that the DH network continues to provide a heat sink when no other cooling is available. Based on the findings presented herein, a set of recommendations have been set up to provide advice to, among others, DH utilities and owners of customer buildings. (C) 2009 Elsevier Ltd. All rights reserved.},
  author       = {Lauenburg, Patrick and Johansson, P. -O. and Wollerstrand, Janusz},
  issn         = {1872-9118},
  keyword      = {Natural circulation,Space heating,District heating,Power failure,Island-operation},
  language     = {eng},
  number       = {4},
  pages        = {1176--1186},
  publisher    = {Elsevier},
  series       = {Applied Energy},
  title        = {District heating in case of power failure},
  url          = {http://dx.doi.org/10.1016/j.apenergy.2009.08.018},
  volume       = {87},
  year         = {2010},
}