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Journal articles on the topic 'District heating pipes'

Author: Grafiati

Published: 4 June 2021

Last updated: 17 February 2022

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1

Kuprys, Algirdas, and Ramūnas Gatautis. "COMPARISON REFURBISHMENT MODELS OF DISTRICT HEATING NETWORKS." JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 20, no. 1 (October 24, 2013): 11–20. http://dx.doi.org/10.3846/13923730.2013.812576.

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The renovation of multi-storey residential buildings reduces heat consumption intensity and decreases heat demand, which may have a harmful effect on a district heating supply system. The paper analyses the heat loss change in four district heating distribution networks (DHNs) of Kaunas at the various scenarios of buildings and DHN renovation stages. A bundle of genetic algorithm software package was used to carry out the districts’ distribution network hydraulic calculations in the case of building renovation without changing the hydrodynamic and network routes. The experimental data were used to calculate heat loss for old and new pipes. The computer data of networks used to summarise the cost of DHN then for the renovation of buildings as well as for renovation progress will go evenly with DHN refurbishment. Network optimization results were summarised by functional dependence. The comparison of the projects’ efficiency was analysed in the following cases: the diameters of pipes of DHN were not changed, new diameters of pipes were integrated partly after partial residential buildings renovation and after a complete renovation of residential building and optimisation of pipeline diameters. The efficiency of separate guidelines of the DHN refurbishment project was summarised by performing sensitivity analysis.

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2

Leuteritz, Andreas, Klaus-Dieter Döring, Thomas Lampke, and Ines Kuehnert. "Accelerated ageing of plastic jacket pipes for district heating." Polymer Testing 51 (May 2016): 142–47. http://dx.doi.org/10.1016/j.polymertesting.2016.03.012.

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3

B�hm, Benny. "On transient heat losses from buried district heating pipes." International Journal of Energy Research 24, no. 15 (2000): 1311–34. http://dx.doi.org/10.1002/1099-114x(200012)24:15<1311::aid-er648>3.0.co;2-q.

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4

Weidlich, Ingo, Marcus Illguth, and Gersena Banushi. "Reserves in axial shear strength of district heating pipes." Energy Procedia 147 (August 2018): 78–85. http://dx.doi.org/10.1016/j.egypro.2018.07.037.

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5

Wolfrum, Dominik, and Thomas Neidhart. "District heating pipes buried in Temporarily Flowable Backfill Materials." Energy Procedia 149 (September 2018): 170–78. http://dx.doi.org/10.1016/j.egypro.2018.08.181.

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6

Khosravi, Milad, and Ahmad Arabkoohsar. "Thermal-Hydraulic Performance Analysis of Twin-Pipes for Various Future District Heating Schemes." Energies 12, no. 7 (April 4, 2019): 1299. http://dx.doi.org/10.3390/en12071299.

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Future energy systems will come with a 100% share of renewable energy and high integration of energy systems. District heating and cooling systems will be undeniable parts of the future energy systems, as they pave the bed for high-efficiency, low cost, and clean production. District heating systems may come into a wide range of designs in the future. Currently, most of the world’s district heating systems are based on the third generation design while everything in this framework is on the verge of a transition to the fourth generation. A large number of technologies for the future district heating systems has been proposed so far, among which low-, ultralow- and variable-temperature systems seem more of qualification. This study employs computational fluid dynamics to make a comprehensive examination of the compatibility of regular twin-pipes with various potential district heating schemes for future energy systems. The results show that both low- and ultralow-temperature systems could efficiently use regular twin-pipes commonly used in the third generation district heating systems, though the insulation of the pipe could be proportionally strengthened based on a techno-economic trade-off. In contrast, the results show that the thermal inertia of the pipe does not allow the variable-temperature district heating system to effectively operate when the transmission pipeline is longer than a limited length. Therefore, a regular heat distribution network may not be an appropriate host for a variable-temperature district heating scheme unless decentralized heat production units come into service.

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7

Mangs, Sara, Morgan Fröling, Olle Ramnäs, and Ulf Jarfelt. "Transport of 1,1,1,3,3-Pentafluorobutane (HFC-365mfc) in Rigid Polyurethane Foam and Polyethylene." Cellular Polymers 21, no. 3 (May 2002): 155–64. http://dx.doi.org/10.1177/026248930202100301.

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This study focuses on the mass transfer properties of 1,1,1,3,3-pentafluorobutane (HFC-365mfc) in the insulating system used in most district heating pipes produced today, namely rigid polyurethane (PUR) foam with a protective layer of polyethylene (HDPE). The solubility, permeability and diffusion coefficients for HFC-365mfc in PUR foam and HDPE have been determined. The coefficients for HFC-365mfc in PUR foam are very similar to those of cyclopentane, currently the most common blowing agent in PUR foams used for district heating pipes in Europe. The polyethylene casing is a better diffusion barrier for HFC-365mfc than it is for cyclopentane. However, the main mass transfer resistance of HFC-365mfc in a district heating pipe is found in the PUR foam.

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8

Babus'Haq, R. F., S. D. Probert, and M. J. Shilston. "Steady State Heat Losses from Horizontal Pipes in an Air-Filled Rectangular Concrete Duct." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 199, no. 3 (July 1985): 203–13. http://dx.doi.org/10.1243/pime_proc_1985_199_115_02.

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Factors influencing the steady state heat loss behaviours of horizontal ‘supply’ and ‘return’ hot-water pipes, within an atmospheric pressure air-filled, relatively cold, horizontal rectangular trench, are considered. An experimental investigation concerning the effects of the displacement ratios for the two pipes revealed the optimal configuration, that is one which achieves a minimum steady state rate of heat loss from the supply pipe. For one set of temperatures for the pipes and trench walls, the optimal configuration of the supply and return pipes occurred at displacement ratios of +0.70 and −0.05, that is with the supply pipe in the upper region of the cavity and the return pipe vertically below it, the pipes being equidistant from the vertical walls of the trench. This configuration is of significance with respect to achieving maximum energy thrift for district heating pipelines, because it differs radically from the ‘side-by-side’ arrangement of pipes conventionally adopted in district heating practice.

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9

Li, Zhen, Wei Wei Wang, and Hong Ming Sun. "Life Cycle Assessment of the District Heating Distribution System in China — Network Construction." Applied Mechanics and Materials 256-259 (December 2012): 2662–66. http://dx.doi.org/10.4028/www.scientific.net/amm.256-259.2662.

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In China, the environmental impact from the construction of the distribution system is seldom discussed. In this study, the environmental impact from construction of district pipes is considered. The purpose is to identify environmental significant parts in the construction of district pipes and to use the results in the actual projects including once more parts of the district distribution system have been investigated with LCA methodology.(Methods) Construction of district pipe networks according to the technical specification was studied. The total consumption of energy and materials was calculated based on budget norm for projects. The functional unit used in the study is construction of 100 metres of pipe system. The studied pipes are: pipe of the dimension DN100, DN200 (Seamless steel tubes) and DN500 (spirally welded steel tubes) .Urban environment surroundings were studied. A short description of the inventory, some inventory results and a life cycle impact assessment are presented. Based on the concept of the End-point damage weighting method, the total environment load is given.

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10

Dong, Yuan Yuan, Fei Wang, Yong Gang Lei, and Guo Wei Wang. "Equivalent Stress Cycles Based on District Heating Operation." Applied Mechanics and Materials 713-715 (January 2015): 295–99. http://dx.doi.org/10.4028/www.scientific.net/amm.713-715.295.

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We investigated supply water temperature of the district boiler between 2006 and 2014.And calculated the design life cycles of heating pipeline based on the district boiler as the heat source. Then superposed the number of the design life cycles caused by pipelines accidents and district boiler of the main trunk lines, distribution lines and subscriber connection line, we obtained the design life cycles of different heating pipes. This result can provide a basis for fatigue damage analysis of heating pipe fittings.

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11

İlhan, Utku. "Optimum insulation thickness for pipes in district heating systems – review." Journal of Mechanical and Energy Engineering 2, no. 3 (December 7, 2018): 225–32. http://dx.doi.org/10.30464/jmee.2018.2.3.225.

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12

Tereshchenko, Tymofii, and Natasa Nord. "Importance of Increased Knowledge on Reliability of District Heating Pipes." Procedia Engineering 146 (2016): 415–23. http://dx.doi.org/10.1016/j.proeng.2016.06.423.

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13

Vega, A., N. Yarahmadi, and I. Jakubowicz. "Optimal conditions for accelerated thermal ageing of district heating pipes." Energy Procedia 149 (September 2018): 79–83. http://dx.doi.org/10.1016/j.egypro.2018.08.171.

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14

Chang, Yoon-Suk, Sung-Wook Jung, Sang-Min Lee, Jae-Boong Choi, and Young-Jin Kim. "Fatigue data acquisition, evaluation and optimization of district heating pipes." Applied Thermal Engineering 27, no. 14-15 (October 2007): 2524–35. http://dx.doi.org/10.1016/j.applthermaleng.2007.02.001.

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15

Arabkoohsar, Ahmad, Ali Sulaiman Alsagri, and Milad Khosravi. "Thermal performance analysis of triple pipes for district heating systems." Journal of Thermal Analysis and Calorimetry 139, no. 3 (August 7, 2019): 1993–2003. http://dx.doi.org/10.1007/s10973-019-08643-5.

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16

Rogoža, Artur. "ESTIMATION OF EXISTING DISTRICT HEATING DISTRIBUTION NETWORK FROM THE STANDPOINT OF LIFE CYCLE ANALYSIS." JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 9, no. 2 (June 30, 2003): 104–9. http://dx.doi.org/10.3846/13923730.2003.10531312.

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Life cycle analysis is a widespread method in most countries. Its principle is to evaluate direct and indirect influences of searching object on environment during its all life cycle. Life cycle model calculations of two existing district heating distribution networks were investigated in this case. Two variants of district heating network maintenance works were computed and compared: renovations using pipes assembled in channels and pre-insulated pipes technologies. Primary energy, heat losses, expenses for maintenance works and heat losses were calculated. The most suitable periodicities of maintenance works and character of the networks depreciation using those periodicities were determined.

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17

Soltero, Víctor, Ricardo Chacartegui, Carlos Ortiz, and Gonzalo Quirosa. "Techno-Economic Analysis of Rural 4th Generation Biomass District Heating." Energies 11, no. 12 (November 25, 2018): 3287. http://dx.doi.org/10.3390/en11123287.

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Biomass heating networks provide renewable heat using low carbon energy sources. They can be powerful tools for economy decarbonization. Heating networks can increase heating efficiency in districts and small size municipalities, using more efficient thermal generation technologies, with higher efficiencies and with more efficient emissions abatement technologies. This paper analyzes the application of a biomass fourth generation district heating, 4GDH (4th Generation Biomass District Heating), in a rural municipality. The heating network is designed to supply 77 residential buildings and eight public buildings, to replace the current individual diesel boilers and electrical heating systems. The development of the new fourth district heating generation implies the challenge of combining using low or very low temperatures in the distribution network pipes and delivery temperatures in existing facilities buildings. In this work biomass district heating designs based on third and fourth generation district heating network criteria are evaluated in terms of design conditions, operating ranges, effect of variable temperature operation, energy efficiency and investment and operating costs. The Internal Rate of Return of the different options ranges from 6.55% for a design based on the third generation network to 7.46% for a design based on the fourth generation network, with a 25 years investment horizon. The results and analyses of this work show the interest and challenges for the next low temperature DH generation for the rural area under analysis.

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18

Wang, Zhao, Zhen Li, and Hong Ming Sun. "Life Cycle Assessment of District Heating Distribution Networks in China — Pipe Production." Applied Mechanics and Materials 256-259 (December 2012): 2652–55. http://dx.doi.org/10.4028/www.scientific.net/amm.256-259.2652.

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In China, the environmental impact from the construction of the distribution system is seldom discussed. In this study, the environmental impacts in production of district pipes are considered. The functional unit used in the study is production of one pipe unit. The studied pipes are: pipe of the dimension DN100, DN200 (Seamless steel tubes) and DN500 (spirally welded steel tubes) with specified length (12m). Based on the concept of the Distance-to-Target weighting method, the total environment load is given. The results can be used to identify environmental significant parts in the actual projects including once more parts of the district distribution system have been investigated with LCA methodology.

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19

Gabrielaitienė, Irena, Rimantas Kačianauskas, and Bengt Sunden. "THERMO-HYDRAULIC FINITE ELEMENT MODELLING OF DISTRICT HEATING NETWORK BY THE UNCOUPLED APPROACH." JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 9, no. 3 (September 30, 2003): 153–62. http://dx.doi.org/10.3846/13923730.2003.10531321.

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The modelling of uncoupled fluid flow and heat transfer problems of a district heating network using the finite element method (FEM) is presented. Since the standard thermo-hydraulic pipe elements cannot be directly used for modelling insulation, the main attention was paid to discretisation of multilayered structure of pipes and surrounding by one-dimensional thermal elements. In addition, validity of the finite element method was verified numerically by solving fluid flow and heat transfer problems in district heating pipelines. Verification analysis involves standard single pipe problems and simulation of fragment of district heating in Vilnius. Pressure and temperature results obtained by finite element method are compared with those by other approaches.

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20

Howard, Daniel Anthony, Konstantin Filonenko, Frederik Stjernholm Busk, and Christian Veje. "Methodology for Evaluation of District Heating Network Efficiency." E3S Web of Conferences 186 (2020): 01006. http://dx.doi.org/10.1051/e3sconf/202018601006.

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The definition of overall district heating network performance indicators is under-investigated in the literature. This study reviews existing methods of performance estimation and develops a convenient methodology for an array of district heating networks applied to a Danish case study. Performances of the networks with state-of-art pipe transmission coefficients are compared to older traditional pipes using an effective average approach. The reported efficiencies and analysis of contributing factors show, that a single parameter is not sufficient to compare large-scale district heating systems and a multiparametric analysis must be employed. The effective average total heat transmission coefficient is evaluated based on the Technical Evaluation Factor and a multivariate regression is performed on typical sets of network parameters: pipe type, pipe series, pipe age, and operational temperature. The developed methodology is applied to testing an array of geographically independent district heating networks, pointing to possible performance bottlenecks, and discussing potential remedies.

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21

Kudela, Libor, Radomir Chylek, and Jiri Pospisil. "Performant and Simple Numerical Modeling of District Heating Pipes with Heat Accumulation." Energies 12, no. 4 (February 16, 2019): 633. http://dx.doi.org/10.3390/en12040633.

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This paper compares approaches for accurate numerical modeling of transients in the pipe element of district heating systems. The distribution grid itself affects the heat flow dynamics of a district heating network, which subsequently governs the heat delays and entire efficiency of the distribution. For an efficient control of the network, a control system must be able to predict how “temperature waves” move through the network. This prediction must be sufficiently accurate for real-time computations of operational parameters. Future control systems may also benefit from the accumulation capabilities of pipes. In this article, the key physical phenomena affecting the transients in pipes were identified, and an efficient numerical model of aboveground district heating pipe with heat accumulation was developed. The model used analytical methods for the evaluation of source terms. Physics of heat transfer in the pipe shells was captured by one-dimensional finite element method that is based on the steady-state solution. Simple advection scheme was used for discretization of the fluid region. Method of lines and time integration was used for marching. The complexity of simulated physical phenomena was highly flexible and allowed to trade accuracy for computational time. In comparison with the very finely discretized model, highly comparable transients were obtained even for the thick accumulation wall.

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22

Kim, Joo-Yong, Sang-Youn Lee, Hyun-Il Ko, and Chong-Du Cho. "Study on Local Buckling of District Heating Pipes Using Limit State Design." Transactions of the Korean Society of Mechanical Engineers A 34, no. 12 (December 1, 2010): 1829–36. http://dx.doi.org/10.3795/ksme-a.2010.34.12.1829.

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23

Vega, Alberto, Nazdaneh Yarahmadi, Jan Henrik Sällström, and Ignacy Jakubowicz. "Effects of cyclic mechanical loads and thermal ageing on district heating pipes." Polymer Degradation and Stability 182 (December 2020): 109385. http://dx.doi.org/10.1016/j.polymdegradstab.2020.109385.

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24

Olsson, Maria, Ulf Jarfelt, Morgan Fröling, and Olle Ramnäs. "The Polyethylene Casing as Diffusion Barrier for Polyurethane Insulated District Heating Pipes." Cellular Polymers 20, no. 1 (January 2001): 37–48. http://dx.doi.org/10.1177/026248930102000103.

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25

Eriksson, Daniel, and Bengt Sundén. "Heat and Mass Transfer in Polyurethane Insulated District Cooling and Heating Pipes." Journal of Thermal Envelope and Building Science 22, no. 1 (July 1998): 49–71. http://dx.doi.org/10.1177/109719639802200105.

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26

Mangs, Sara, Olle Ramnäs, and Ulf Jarfelt. "Mass Transport of Cell Gases in Carbon Dioxide Blown PET (Polyethylene Terephthalate) Foam Insulation." Cellular Polymers 24, no. 3 (May 2005): 115–26. http://dx.doi.org/10.1177/026248930502400301.

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Polyethylene terephthalate (PET) foam is a possible replacement option for polyurethane (PUR) foam as insulation material in district heating pipes. In this study, the diffusion coefficients and activation energies of cell gases in carbon dioxide blown PET foam (densities 148–157 kg·m−3) were determined at temperatures between 23 °C and 90 °C. The foam thermal ageing due to the mass transport of air into and carbon dioxide out of the foam was about ten times slower in PET foam than in PUR foam. The thermal conductivities of the PET foam boards were determined in a heat flow meter apparatus. The contribution to the foam thermal conductivity due to conduction in the solid polymer and radiation within the cell voids was determined to 17 mW·m−1·K−1 at 20 °C. This is higher than the value estimated for PUR foam in district heating pipes, 12 mW·m−1·K−1. This contribution can probably be reduced by developing low density PET foam and reducing the cell size.

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27

Langroudi, Pakdad Pourbozorgi, and Ingo Weidlich. "Applicable Predictive Maintenance Diagnosis Methods in Service-Life Prediction of District Heating Pipes." Environmental and Climate Technologies 24, no. 3 (November 1, 2020): 294–304. http://dx.doi.org/10.2478/rtuect-2020-0104.

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AbstractMaintaining the supply chain in every industry is an important concern for the operators. The negative impacts of inappropriate maintenance could be discussed from different perspectives as well as capital loss, reputation loss, hazard and risk for lives, etc. In recent years, District heating (DH) in the countries that employing this technology broadly, turned to a vital energy infrastructure for delivering heat from suppliers to the consumers. Therefore, the reliability of the system is of high importance for the public interest. The transition from reactive maintenance to proactive maintenance have improved a lot the reliability to the system. Currently, many industries are exploiting different forms of artificial intelligence (AI) to predict the failures and plan for interventions to increase the system efficiency. In this paper the different methods of predictive maintenance have been reviewed and the compatibility to apply on a DH network has been discussed.

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28

Vega, Alberto, Nazdaneh Yarahmadi, and Ignacy Jakubowicz. "Determination of the long-term performance of district heating pipes through accelerated ageing." Polymer Degradation and Stability 153 (July 2018): 15–22. http://dx.doi.org/10.1016/j.polymdegradstab.2018.04.003.

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29

BØhm, B. "Experimental Determination of Heat Losses from Buried District Heating Pipes in Normal Operation." Heat Transfer Engineering 22, no. 3 (June 2001): 41–51. http://dx.doi.org/10.1080/01457630118274.

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30

Svanström, Magdalena, Olle Ramnäs, Maria E. Olsson, and Ulf Jarfelt. "Mass Transfer of Carbon Dioxide through the Polyethylene Casing of District Heating Pipes." Journal of Thermal Insulation and Building Envelopes 21, no. 2 (October 1997): 171–84. http://dx.doi.org/10.1177/109719639702100207.

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31

Berge, A., and B. Adl-Zarrabi. "Long term performance of vacuum insulation panels in hybrid insulation district heating pipes." Energy Procedia 116 (June 2017): 334–42. http://dx.doi.org/10.1016/j.egypro.2017.05.080.

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32

Berge, Axel, Bijan Adl-Zarrabi, and Carl-Eric Hagentoft. "Assessing the Thermal Performance of District Heating Twin Pipes with Vacuum Insulation Panels." Energy Procedia 78 (November 2015): 382–87. http://dx.doi.org/10.1016/j.egypro.2015.11.678.

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33

Zhang, Lianying, Zhenni Wang, Xiaohu Yang, Liwen Jin, Qunli Zhang, and Wenju Hu. "Thermo-economic Analysis for Directly-buried Pipes Insulation of District Heating Piping Systems." Energy Procedia 105 (May 2017): 3369–76. http://dx.doi.org/10.1016/j.egypro.2017.03.759.

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34

Martin-Du Pan, Oliver, Paul Woods, and Richard Hanson-Graville. "Optimising pipe sizing and operating temperatures for district heating networks to minimise operational energy consumption." Building Services Engineering Research and Technology 40, no. 2 (September 27, 2018): 237–55. http://dx.doi.org/10.1177/0143624418802590.

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Reducing heat losses is an important factor in improving the performance of district heating networks. High heat losses are sometimes experienced in UK district heating networks and this is often as a result of poor design, partly due to oversized pipes. To provide additional guidance to designers on this issue, this paper proposes a set of maximum pipe diameters to be used for a given maximum flow rate to reduce the risk of oversizing and high heat losses. It was found that the optimised velocities are higher than those given in CIBSE CP1 Heat Networks Code of Practice and adopting these will result in smaller pipe diameters and lower operational and capital costs. The methodology used in this paper is based on minimising the total operational energy. The flow and return optimised pipe diameters are calculated for different scenarios which include variations in the pipe material, insulation thickness, water temperature and ambient environment. It was found that the optimised velocity in every scenario remains relatively constant with a varying pipe diameter. This paper shows that the operational cost of a DH network can be reduced when selecting the recommended maximum pipe diameter, compared to commonly used sizing criteria. Further savings can be achieved if the flow and return pipe are sized separately; to minimise operational energy of both flow and return pipes, the return pipe should be sized for a lower velocity. This paper also explores particular questions of interest: A range of insulation thicknesses. Benefit from using a variable flow temperature and to supply the flow at 90℃ at peak times instead of a constant temperature at 70℃. A comparison between steel and plastic pipes which have different roughness coefficients. Optimised differential pressure drop per unit length in both flow and return pipes. Maximum distance occurring before measuring a temperature loss and pressure drop of 1℃ and 1 bar, respectively, at peak load. However, this paper does not take into account any potential benefits that a lower flow temperature might have in reducing heat production costs or a lower return temperature might have in enhanced heat recovery, or that lower temperatures may enable use of plastic carrier pipes. Such matters are site specific but should be included in any similar pipe sizing analysis and operating temperature optimisation carried out for an actual scheme. Practical application: Optimising maximum pipe diameters is necessary to improve the viability of district heating systems. The current guidance for designers is not considered optimal and this paper suggests a new methodology to size pipes to reduce both the heat losses and the operational cost. This paper also gives guidance to sustainability engineers to assess the performance of 90/40℃, 70/40℃ and 60/30℃ district heating networks; 70℃ was assumed to be the minimum acceptable flow temperature in the network to enable domestic hot water to be heated to a safe temperature of 60℃ for storage; 40℃ was the used return temperature to be in line with the CIBSE Code of Practice CP1 stating in Objective 3.5 that best practice should achieve return temperatures below 40℃ for a scheme supplying heat to new buildings. A 90/40℃ DH network performance when increasing the flow temperature was then compared to the performance of a 70/40℃ system. Finally, a 60/30℃ system was also analysed to investigate the benefit from operating a DH network complying with the 4th generation of DH network temperatures that encourages minimal exergy destruction from the network to the end user.

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35

Aleksahin, A., A. Boblovskii, K. Miahkokhlib, and Y. Schactnyi. "INDICATORS THERMAL AND HYDRAULIC MODES OF DISTRIBUTION HEAT NETWORKS." Municipal economy of cities 3, no. 163 (June 29, 2021): 7–11. http://dx.doi.org/10.33042/2522-1809-2021-3-163-7-11.

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The task of heat supply systems is to ensure the quality of services at a minimum cost in the production and transportation of thermal energy. Because the distribution heat networks of district and district systems are characterized by significant branching and significantly longer lengths of heat pipelines compared to the main sections of heating networks, reducing heat loss in these elements of the heating system significantly affects the overall efficiency of district heating. The amount of heat loss depends on the method of laying networks and the diameter of heat pipes, thermal insulation parameters and temperature of the coolant and the environment. Based on the formulas for determining the specific pressure losses to overcome the friction forces obtained from the generalization of these projects of central heating systems of a number of residential districts of Kharkiv, calculated dependences for determining heat losses by supply and return pipelines of the main branches of the heating network. Estimates of accuracy of use of the offered formulas are carried out. The aim of the work is to determine the specific pressure losses for the main branches of heating distribution networks on the basis of generalization of design data for heat supply systems of building groups and clarification of formulas for calculating heat losses by pipelines of central heating distribution system. Based on the generalization of projects for the heating network of residential neighborhoods in Kharkiv, a formula for calculating the specific pressure loss during water movement in the pipelines of the main branches of the heating network depending on the heat load of buildings connected to the branch. Formulas for calculation of heat losses by supply and return pipelines of the main branches of a heating network of the residential district are offered. A comparison of the accuracy of calculations using the proposed formulas with existing methods for determining heat loss in branched heat supply networks, which showed the possibility of using formulas in preliminary assessments of the thermal state of networks.

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36

Kudela, Libor, Radomír Chýlek, and Jiří Pospíšil. "Efficient Integration of Machine Learning into District Heating Predictive Models." Energies 13, no. 23 (December 2, 2020): 6381. http://dx.doi.org/10.3390/en13236381.

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Modern control strategies for district-level heating and cooling supply systems pose a difficult challenge. In order to integrate a wide range of hot and cold sources, these new systems will rely heavily on accumulation and much lower operating temperatures. This means that predictive models advising the control strategy must take into account long-lasting thermal effects but must not be computationally too expensive, because the control would not be possible in practice. This paper presents a simple but powerful systematic approach to reducing the complexity of individual components of such models. It makes it possible to combine human engineering intuition with machine learning and arrive at comprehensive and accurate models. As an example, a simple steady-state heat loss of buried pipes is extended with dynamics observed in a much more complex model. The results show that the process converges quickly toward reasonable solutions. The new auto-generated model performs 5 × 104 times faster than its complex equivalent while preserving essentially the same accuracy. This approach has great potential to enhance the development of fast predictive models not just for district heating. Only open-source software was used, while OpenModelica, Python, and FEniCS were predominantly used.

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37

Vega, Alberto, Nazdaneh Yarahmadi, and Ignacy Jakubowicz. "Determining the useful life of district heating pipes: Correlation between natural and accelerated ageing." Polymer Degradation and Stability 175 (May 2020): 109117. http://dx.doi.org/10.1016/j.polymdegradstab.2020.109117.

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38

Dige Pedersen, Jakob, and Benny Bøhm. "On the calibration and application of heat flux sensors on buried district heating pipes." International Journal of Energy Research 24, no. 12 (2000): 1041–48. http://dx.doi.org/10.1002/1099-114x(20001010)24:12<1041::aid-er643>3.0.co;2-c.

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39

Dénarié, A., M. Aprile, and M. Motta. "Heat transmission over long pipes: New model for fast and accurate district heating simulations." Energy 166 (January 2019): 267–76. http://dx.doi.org/10.1016/j.energy.2018.09.186.

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Kılkış, Birol, Malik Çağlar, and Mert Şengül. "Energy Benefits of Heat Pipe Technology for Achieving 100% Renewable Heating and Cooling for Fifth-Generation, Low-Temperature District Heating Systems." Energies 14, no. 17 (August 30, 2021): 5398. http://dx.doi.org/10.3390/en14175398.

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This paper addresses the challenges the policymakers face concerning the EU decarbonization and total electrification roadmaps towards the Paris Agreement set forth to solve the global warming problem within the framework of a 100% renewable heating and cooling target. A new holistic model was developed based on the Rational Exergy Management Model (REMM). This model optimally solves the energy and exergy conflicts between the benefits of using widely available, low-temperature, low-exergy waste and renewable energy sources, like solar energy, and the inability of existing heating equipment, which requires higher exergy to cope with such low temperatures. In recognition of the challenges of retrofitting existing buildings in the EU stock, most of which are more than fifty years old, this study has developed a multi-pronged solution set. The first prong is the development of heating and cooling equipment with heat pipes that may be customized for supply temperatures as low as 35 °C in heating and as high as 17 °C in cooling, by which equipment oversizing is kept minimal, compared to standard equipment like conventional radiators or fan coils. It is shown that circulating pump capacity requirements are also minimized, leading to an overall reduction of CO2 emissions responsibility in terms of both direct, avoidable, and embodied terms. In this respect, a new heat pipe radiator prototype is presented, performance analyses are given, and the results are compared with a standard radiator. Comparative results show that such a new heat pipe radiator may be less than half of the weight of the conventional radiator, which needs to be oversized three times more to operate at 35 °C below the rated capacity. The application of heat pipes in renewable energy systems with the highest energy efficiency and exergy rationality establishes the second prong of the paper. A next-generation solar photo-voltaic-thermal (PVT) panel design is aimed to maximize the solar exergy utilization and minimize the exergy destruction taking place between the heating equipment. This solar panel design has an optimum power to heat ratio at low temperatures, perfectly fitting the heat pipe radiator demand. This design eliminates the onboard circulation pump, includes a phase-changing material (PCM) layer and thermoelectric generator (TEG) units for additional power generation, all sandwiched in a single panel. As a third prong, the paper introduces an optimum district sizing algorithm for minimum CO2 emissions responsibility for low-temperature heating systems by minimizing the exergy destructions. A solar prosumer house example is given addressing the three prongs with a heat pipe radiator system, next-generation solar PVT panels on the roof, and heat piped on-site thermal energy storage (TES). Results showed that total CO2 emissions responsibility is reduced by 96.8%. The results are discussed, aiming at recommendations, especially directed to policymakers, to satisfy the Paris Agreement.

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Hamburg, Anti, and Targo Kalamees. "The influence of heat loss from pipes in an unheated basement on the heating energy consumption of an entire typical apartment building." E3S Web of Conferences 172 (2020): 12005. http://dx.doi.org/10.1051/e3sconf/202017212005.

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The majority of old apartment buildings were designed with an unheated basement. Building service systems such as district heating heat exchangers and pipes for domestic hot water and for space heating are usually located in this unheated basement. In addition, these locations are connected with shafts. All these pipe’s heat losses increase air temperature in the basement. If these losses are included into the building energy balance, then they decrease heat loss through the basement ceiling. The basement’s heat balance is also dependent on heat loss from the basement envelope and outdoor air exchange in the basement. In early stages of design, designers and energy auditors need rough models to make decisions in limited information conditions. Once the effects of heat losses from pipes become apparent, they need to be factored into the buildings energy balance, and their effects on heat loss through the basement ceiling needs to be calculated. In this paper we analyse the effect these heat losses have on the service system’s heat gains and heat loss through an uninsulated basement ceiling at different basement insulation levels and with different thicknesses of pipe insulation. From our study we found that pipe losses in the basement increase the building energy performance value by at least 4 kWh/(m²∙a) and their impact on a renovated apartment building is very important.

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Pimentel de Sousa Júnior, Roberto, Renato Pinto Cunha, and Rideci de Jesus da Costa Farias. "Geothermal response of a geothermal system for energy piles in a typical Brazilian tropical soil." E3S Web of Conferences 205 (2020): 05005. http://dx.doi.org/10.1051/e3sconf/202020505005.

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For a long time ago energy piles systems have been used for heating and/ or cooling purposes. The proposal of a conditioning system for closed environments that is economical and sustainable has drawn attention in Brazil, a country that is experiencing energy difficulties and have a high demand for thermal conditioning in most of its territory. Different configurations of foundation blocks were simulated, and an extensive geological-geotechnical survey of the soil chosen as representative of the Federal District, allowed the calculation of the thermal parameters of this soil. With these parameters the next step were the numerical simulations, the aim of this paper, which varied the foundations with the number of pile caps, piles diameter and turns in the pipe, seeking the best configuration for the region studied. As a result of this work, it was concluded that for blocks with pile diameters of 30 and 40 cm, the ideal is the use of only two turns in the pipes for blocks with 4 or more piles, while for piles of 60 cm three turns in the pipe generates a maximum exchange of heat. It is also concluded that the soil of the Federal District has a high potential for heat exchange.

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Pericault, Youen, Erik Kärrman, Maria Viklander, and Annelie Hedström. "Expansion of Sewer, Water and District Heating Networks in Cold Climate Regions: An Integrated Sustainability Assessment." Sustainability 10, no. 10 (October 17, 2018): 3743. http://dx.doi.org/10.3390/su10103743.

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This study presents an integrated sustainability assessment of technical alternatives for water and heating services provision in suburban areas affected by a cold climate. Each alternative combines a drinking water supply, sewerage (gravity or low-pressure), pipe freeze protection (deep burial or shallow burial with heat tracing) and heating solution (district heating or geothermal heat pumps). An innovative freeze protection option was considered, in which low-temperature district heating (LTDH) is used to heat trace shallow sewer and water pipes. First, the performance of each alternative regarding seven sustainability criteria was evaluated on a projected residential area in Sweden using a systems analysis approach. A multi-criteria method was then applied to propose a sustainability ranking of the alternatives based on a set of weights obtained from local stakeholders. The alternative with a deep buried gravity sewer and geothermal heat pumps was found to have the highest sustainability score in the case study. In the sensitivity analysis, the integrated trench solution with a gravity sewer, innovative heat tracing and LTDH was found to potentially top the sustainability ranking if geothermal energy was used as the district heating source, or if the weight of the cost criterion increased from 24% to 64%. The study highlights the need for integrated decision-making between different utility providers as an integrated solution can represent sustainability gains.

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Chicherin, Stanislav, Lyazzat Junussova, and Timur Junussov. "Minimizing the supply temperature at the district heating plant – dynamic optimization." E3S Web of Conferences 118 (2019): 02004. http://dx.doi.org/10.1051/e3sconf/201911802004.

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The constraint contains two elements, namely the heat losses and the electricity consumption for pumping at the producer. The aim was to achieve the lowest acceptable costs in an operation. The options with the supply temperature at the area starting point set to 80/60, then 60/40, and eventually 50/30 (low temperature, 4th generation district heating) were tested. The balance between the savings due to lower heat losses and the electricity consumption of pumps could be performed to assess the economic viability of the solution. This means that if the electricity price is sufficiently high, the model will always choose to minimize electricity consumption and thereby, maximise the profit from high temperature difference. Results concerning heat losses consider both experiences of proper insulation of pipes with variety of design outdoor temperatures (DOTs) and long term measurements from a pump station for district heating (DH) network in Canberra, Australia. We also noted that the heat energy tariffs and purchase price of electricity affect a lot optimal configuration of a DH system. For the best scenario, solutions are obtained that reach over 12% of the available saving potential after calculating 11 equations. Knowing that the policy is updated on a case study base, this is considered a promising result.

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Olsson, Maria E., Ulf Jarfelt, Morgan Fröling, Sara Mangs, and Olle RamnäS. "Diffusion of Cyclopentane in Polyurethane Foam at Different Temperatures and Implications for District Heating Pipes." Journal of Cellular Plastics 38, no. 2 (March 2002): 177–88. http://dx.doi.org/10.1177/0021955x02038002248.

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Arabkoohsar, Ahmad, Milad Khosravi, and Ali Sulaiman Alsagri. "CFD analysis of triple-pipes for a district heating system with two simultaneous supply temperatures." International Journal of Heat and Mass Transfer 141 (October 2019): 432–43. http://dx.doi.org/10.1016/j.ijheatmasstransfer.2019.06.101.

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Yarahmadi, Nazdaneh, Alberto Vega, and Ignacy Jakubowicz. "Determination of essential parameters influencing service life time of polyurethane insulation in district heating pipes." Energy Procedia 116 (June 2017): 320–23. http://dx.doi.org/10.1016/j.egypro.2017.05.078.

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Domhagen, Fredrik, and Bijan Adl-Zarrabi. "Influence of oxidation on radiative heat transfer in polyurethane insulation used for district heating pipes." Energy Procedia 132 (October 2017): 309–14. http://dx.doi.org/10.1016/j.egypro.2017.09.735.

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Alsagri, Ali Sulaiman, Ahmad Arabkoohsar, Milad Khosravi, and Abdulrahman A. Alrobaian. "Efficient and cost-effective district heating system with decentralized heat storage units, and triple-pipes." Energy 188 (December 2019): 116035. http://dx.doi.org/10.1016/j.energy.2019.116035.

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Wang, Ruihuai, Pengfei Jie, Delai Wang, Fating Li, and Chunhua Liu. "Optimization of insulation thickness of double buried district heating pipes using the Eco-indicator method." Journal of Building Engineering 41 (September 2021): 102393. http://dx.doi.org/10.1016/j.jobe.2021.102393.

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