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Jakubek, D., Ocłoń, P., Nowak-Ocłoń, M., Sułowicz, M., Varbanov, P. S., Klemeš, J. J.
Original Title
Mathematical modelling and model validation of the heat losses in district heating networks
Type
journal article in Web of Science
Language
English
Original Abstract
Today the most popular system of district heating systems is based on pre-insulated pipes arranged in parallel or twin-pipe configuration. One of the greatest difficulties with heat distribution through pipelines is thermal loss from the distribution. The most efficient solution to that problem is optimising the insulation wall thickness layer according to the pipe diameter. Heat losses should be minimised at a relatively low investment cost to find the most suitable insulation thickness economically. Numerous studies focus on analytical (1D model) calculations and numerical simulations. However, there is a research gap related to laboratory devices that allow measuring the operation parameters (fluid flow, the temperature of the fluid in the supply pipe and the return pipe). This paper presents an analysis of the heat losses from pre-insulated pipes and twin pipes in the heating system network. This study compares the heat losses in the ground calculated by analytical solution (1D model) with the measurements on the dedicated experimental setup. The calculations have been made for several heating network pipe variants: twin pipes: DN40, DN50, DN65, and their counterparts in a single parallel pre-insulated system. The insulation thickness used in all cases is 30.85 mm for DN40 and 32.00 mm for DN50 and DN65. The insulation is made of rigid polyurethane foam that meets the requirements of the PN-EN 253 standard. During the investigation, the thermal conductivity of insulation material is examined. The obtained thermal conductivity results are used in the calculations. The results from laboratory devices and analytical models have been compared, demonstrating good agreement – with a low error level in the range of approximately 8%, depending on the type of district heating pipe. The validated mathematical model of the heating network is then used to calculate the heat losses in a heating network connecting an underground storage tank with a ground source heat pump. The economic analysis shows that after 5 y, a return on investment is expected when comparing twin-pipe systems and single-pipe pre-insulated heating networks.
Keywords
Heat transfer, District heating network, Heat losses
Authors
Released
15. 3. 2023
ISBN
0360-5442
Periodical
Energy
Year of study
267
Number
126460
State
United Kingdom of Great Britain and Northern Ireland
Pages from
1
Pages to
14
Pages count
4
URL
https://www.sciencedirect.com/science/article/pii/S0360544222033461#kwrds0010
BibTex
@article{BUT180501, author="Petar Sabev {Varbanov} and Jiří {Klemeš}", title="Mathematical modelling and model validation of the heat losses in district heating networks", journal="Energy", year="2023", volume="267", number="126460", pages="1--14", doi="10.1016/j.energy.2022.126460", issn="0360-5442", url="https://www.sciencedirect.com/science/article/pii/S0360544222033461#kwrds0010" }