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Averfalk, H., Ottermo, F. & Werner, S. (2019). Pipe Sizing for Novel Heat Distribution Technology. Energies, 12(7), Article ID 1276.
Open this publication in new window or tab >>Pipe Sizing for Novel Heat Distribution Technology
2019 (English)In: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 12, no 7, article id 1276Article in journal (Refereed) Published
Abstract [en]

This paper assesses pipe sizing aspects for previously proposed, novel, low heat distribution technology with three pipes. Assessment issues include heat loss, pressure loss, and pipe sizing for different typical pipe configurations. This assessment has been provided by the analysis of a case area with single-family houses. Concerning heat loss, the proposed three-pipe solutions have the same magnitude of heat loss as conventional twin pipes, since lower return temperatures compensate for the larger heat loss area from the third pipe. Regarding pressure loss, the main restriction on the size of the third pipe is limited to the pressure loss in the third pipe. Thermostatic valves to manage the flow rate of the third pipe are advocated, since alternative small pumps have not been found to be commercially available. The pipe sizing recommendation is that the third pipe for recirculation purposes can be two to three standard pipe sizes smaller than the corresponding supply and return pipe, if no prosumer is connected in the heat distribution network.

Place, publisher, year, edition, pages
Basel: MDPI, 2019
Keywords
low temperature, district heating, pressure gradients, three-pipe system, 4GDH-3P
National Category
Energy Engineering
Identifiers
urn:nbn:se:hh:diva-39198 (URN)10.3390/en12071276 (DOI)
Projects
TEMPO
Funder
EU, Horizon 2020, 768936
Available from: 2019-04-04 Created: 2019-04-04 Last updated: 2019-04-04Bibliographically approved
Persson, U. & Averfalk, H. (2018). Accessible urban waste heat: Deliverable 1.4.
Open this publication in new window or tab >>Accessible urban waste heat: Deliverable 1.4
2018 (English)Report (Other academic)
Abstract [en]

This report presents the work performed in Task T1.2 of the ReUseHeat project to assess the accessible EU28 urban excess heat recovery potential from four unconventional excess heat sources: data centres, metro stations, service sector buildings, and waste water treatment plants. The report presents in overview and detail the concepts, data, basic premises, and methods, used to produce the results from this work. In all, excess heat potentials are modelled and spatially mapped for a total of some 26,400 unique activities, but by application of two new concepts: available excess heat and accessible excess heat, by which total potentials are distinguished from practical utilisation potentials, a significantly reduced count of some 6800 unique facilities represent the final cut. Common for these facilities are that they all are located inside or within 2 kilometres of urban district heating areas. For the total count of activities, the full available excess heat potential is assessed at some 1.56 EJ per year. At the restrained conditions, thus representing a conservative estimate, the final available excess heat potential from the four unconventional sources is estimated at 0.82 EJ per year, which here corresponds to a final accessible excess heat potential anticipated at 1.24 EJ annually.

Publisher
p. 116
National Category
Energy Systems Remote Sensing
Identifiers
urn:nbn:se:hh:diva-38750 (URN)
Projects
Recovery of Urban Excess Heat (ReUseHeat)
Funder
EU, Horizon 2020, 767429
Available from: 2019-01-09 Created: 2019-01-09 Last updated: 2019-02-12Bibliographically approved
Averfalk, H. & Werner, S. (2018). Efficient heat distribution in solar district heating systems. In: SDH Solar District Heating: Proceeding. Paper presented at 5th International Solar District Heating Conference, Graz, Austria, April 11-12, 2018 (pp. 63-66).
Open this publication in new window or tab >>Efficient heat distribution in solar district heating systems
2018 (English)In: SDH Solar District Heating: Proceeding, 2018, p. 63-66Conference paper, Published paper (Refereed)
Abstract [en]

This paper contains a short analysis showing the main benefit for solar district heating when a novel heat distribution concept with low temperatures is applied. The analysis is performed by comparing the annual solar heat output from a solar collector field for current heat distribution temperatures in Sweden with the corresponding output for the novel heat distribution concept. The results show that the new low temperature concept provides 66% more solar heat for a typical solar collector. Hereby, the solar collector field can be reduced with 40%, giving a corresponding cost reduction for solar heat generated. Another result is that the cost gradient for lower costs from lower return temperatures is five times higher for solar district heating compared to current heat supply in Swedish district heating systems. One major conclusion is that high heat distribution temperatures in current European district heating systems are a major barrier for the competitiveness of solar district heating.

National Category
Energy Engineering
Identifiers
urn:nbn:se:hh:diva-36730 (URN)
Conference
5th International Solar District Heating Conference, Graz, Austria, April 11-12, 2018
Available from: 2018-05-07 Created: 2018-05-07 Last updated: 2018-06-12Bibliographically approved
Averfalk, H. & Werner, S. (2018). Novel low temperature heat distribution technology. Energy, 145, 526-539
Open this publication in new window or tab >>Novel low temperature heat distribution technology
2018 (English)In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 145, p. 526-539Article in journal (Refereed) Published
Abstract [en]

Lower future heat demands and lower availability of non-fossil high temperature heat supply are expected future market conditions that restrain the long-term viability of contemporary district heating systems. Hence, current district heating technology should be enhanced to increase system performance in new heat distribution areas. This paper aims to outline a proposal for technical improvements required to achieve lower annual average return temperatures in new residential buildings to improve viability in future market conditions. The proposed technical solution consists of three principle changes: three-pipe distribution networks, apartment substations, and longer thermal lengths for heat exchangers. The three technical modifications aims at addressing system embedded temperature errors. Furthermore, a simulation model was developed to assess the proposed technical solution concerning different energy performances of buildings and different thermal lengths in heat exchangers. The results show that implementation of the three technical modifications reaches time-weighted annual average return temperatures of 17–21 °C with supply temperatures of about 50 °C. The results also verify the increased necessity to separate the network return flows into delivery and recirculation flows in residential substations as energy performance in buildings increase.

Place, publisher, year, edition, pages
London: Elsevier, 2018
Keywords
Low temperature, District heating, Three-pipe system, Recirculation, 4GDH-3P
National Category
Energy Engineering
Identifiers
urn:nbn:se:hh:diva-38360 (URN)10.1016/j.energy.2017.12.157 (DOI)
Available from: 2018-11-18 Created: 2018-11-18 Last updated: 2019-04-04Bibliographically approved
Averfalk, H., Dalman, B.-G., Kilersjö, C., Lygnerud, K. & Welling, S. (2017). Analys av 4e generationens fjärrvärmeteknik jämfört med 3e generationens: Simulering av sekundärnät i nybyggnationsområde. Stockholm: Energiforsk AB
Open this publication in new window or tab >>Analys av 4e generationens fjärrvärmeteknik jämfört med 3e generationens: Simulering av sekundärnät i nybyggnationsområde
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2017 (Swedish)Report (Other academic)
Abstract [sv]

Bakgrunden till studien är att nya förutsättningar genom energieffektivisering, konkurrens från värmepumpar och nya krav på kundsidan gör en modernisering av fjärrvärmeverksamhet nödvändig. En del av denna modernisering är att kunna dra nytta av de fördelar som lägre temperaturer i näten medför. Därtill skapas genom den nya tekniken förutsättningar för att ta hand om värmekällor som idag inte utnyttjas (t.ex. värme från kylprocesser och annan infrastruktur såsom värme från avloppsvatten och värme från kollektivtrafik).

Befintlig teknik är beprövad och bygger på att det finns ekonomiska incitament att förbränna biobränsle och avfall. Steget till att pröva en ny teknik där andra värmekällor och en ny gränsdragning gentemot kund blir nödvändig är därför stort och förenat med ett antal frågor. Det är just de frågor som uppkommer i ett fjärrvärmeföretag inför implementering av 4e generationens fjärrvärmeteknik som projektet försöker identifiera. Det blir dock så att enbart en del av frågorna besvaras genom att studien har ett avgränsat fokus. Fokus är på jämförelse mellan ett 3GDHtvårörsystem och ett 4GDH-trerörsystem i ett sekundärnät i ett nybyggnationsområde.

I projektet simuleras hur utfallet blir för olika parametrar om man hade valt att implementera 4e generationens teknik istället för 3e generationens teknik.

Resultaten påvisar att:

• 4e generationens lösning ökar energieffektiviteten i byggnader, detta främst genom att behovet av varmvattencirkulation försvinner.• Beaktas enbart distributionsförluster i näten så är 4e generationen mer effektiv än 3e generationen.• Genom lägenhetsväxlaren i 4e generationens lösning så elimineras risken för Legionella helt. En möjlig barriär för 4e generationens teknik består dock i att boverkets byggregler inte är konstruerade för att varmvattencirkulation inte finns.• Lägenhetsväxlarna innebär en kostnad per lägenhet vilket begränsar lösningens kostnadseffektivitet jämfört med en större värmeväxlare i fastighetens bottenplan. Idag är 4e generationens teknik lämpad för fastigheter med 10-15 lägenheter, är det fler lägenheter blir 4e generationens lösning dyrare än den konventionella 3e generationens lösning.• En viktig aspekt med 4e generationens lösning att värmeförlusten från huset förflyttas från fastighetsägaren till fjärrvärmeföretaget, genom att värmeleverans sker till varje lägenhet och inte vid husvägg. Initialt kan sådan börda på fjärrvärmeföretaget verka negativ med avseende på kostnad. Diskussionerna i projektet mynnade ut i att parterna enas om att affären blir mer rättvisande och att fastighetsägaren får ökad insyn i värmeförbrukningen vilket, med rätt affärsmodell, kan skapa ökat förtroende och en möjlighet att dela på förlusten mellan de två parterna.

Projektet har omfattat löpande dialog med EKSTAs VD vilket varit värdefullt för att skapa förståelse kring fastighetsägarens perspektiv och frågor rörande 4e generationens teknik. Därtill har en workshop med EKSTAs driftspersonal hållits för att diskutera relevansen i de resultat som tagits fram. I projektet ingår BengtGöran Dalman med över 35 års erfarenhet av fjärrvärmeverksamhet vid Göteborg Energi. Projektets verklighetskoppling leder till slutsatsen att det inte föreligger någon särskild driftsproblematik för implementering av 4e generationens system.

Som en egen del i projektet uppmärksammas den diskussion som förs i branschen kring möjligheten att dra nytta av billig el, främst under perioder då det blåser mycket och det blir ett överskott av el i elnätet. I studien analyseras möjligheten att inte använda en konventionell pelletspanna som tilläggsvärmekälla utan en eldriven panna. Resultaten visar att med dagens styrning genom skatter och avgifter så är det inte möjligt att dra nytta av att det förekommer perioder med mycket lågt elpris. Rådande regelverk stödjer istället installationer såsom pelletspannor.

© ENERGIFORSK

Place, publisher, year, edition, pages
Stockholm: Energiforsk AB, 2017. p. 39
Series
Energiforsk rapport ; 2018:547
National Category
Energy Engineering
Identifiers
urn:nbn:se:hh:diva-38813 (URN)978-91-7673-547-3 (ISBN)
Projects
Effektiv projektering av fjärde generationens fjärrvärme (4GDH)
Available from: 2019-01-30 Created: 2019-01-30 Last updated: 2019-01-31Bibliographically approved
Averfalk, H. (2017). Enhanced District Heating Technology: Maintaining Future System Feasibility. (Licentiate dissertation). Lund: Lund University Open Access
Open this publication in new window or tab >>Enhanced District Heating Technology: Maintaining Future System Feasibility
2017 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

When heat demand and high temperature heat supply gradually decreases in the future, then it will effect district heating systems ability to compete on the heat market. A good way to mitigate less district heating feasibility is to operate systems with lower temperature levels and the most conceivable way to achieve lower temperature levels is to decrease return temperatures.

Thus, this thesis emphasise temperature errors embedded in district heating systems. Only a selection of temperature errors are analysed in this thesis. First, the temperature error that occurs due to recirculation in distribution networks at low heat demands. Second, the temperature error that occurs due to hot water circulation in multi-family buildings. Third, the temperature error that occurs due to less than possible heat transfer in heat exchangers, i.e. too short thermal lengths.

In order to address these temperature errors three technology changes have been proposed (i) three-pipe distribution network to separate the recirculation return flow from the delivery return flow, (ii) apartment substations to eliminate hot water circulation utilisation, and (iii) improved heat exchangers for lower return temperatures at a constant scenario. Analysis of proposed changes has resulted in annual average return temperatures between 17-21 °C.

Furthermore, rapid introduction of intermittent renewable electricity supply in the energy system has prompted an increased necessity of power system balancing capacities. Large-scale conversion of power-to-heat in electric boilers and heat pumps is a feasible alternative to achieve such balancing capacities. Analysis of the unique Swedish experience with utilisation of large heat pumps installations connected to district heating systems show that since the 1980s 1527 MW of heat power has been installed, about 80 % of the capacity was still in use by 2013. Thus, a cumulative value of over three decades of operation and maintenance exists within Swedish district heating systems.

The two papers presented in this thesis are related to future district heating systems through the five abilities of fourth generation district heating (4GDH), which are documented in the definition paper of 4GDH.

Place, publisher, year, edition, pages
Lund: Lund University Open Access, 2017. p. 75
National Category
Energy Engineering
Identifiers
urn:nbn:se:hh:diva-39199 (URN)978-91-7753-507-2 (ISBN)978-91-7753-508-9 (ISBN)
Presentation
2017-12-18, M:B (M-huset), Ole Römers väg 1, Lund, 13:15 (English)
Opponent
Supervisors
Note

Med populärvetenskaplig sammanfattning på svenska. I publikationen felaktigt: ISSN 0282-1990

Available from: 2019-04-04 Created: 2019-04-04 Last updated: 2019-04-04Bibliographically approved
Averfalk, H. & Werner, S. (2017). Essential improvements in future district heating systems. Paper presented at The 15th International Symposium on District Heating and Cooling, , Seoul, Republic of Korea (South Korea), September 4-7, 2016. Energy Procedia, 116, 217-225
Open this publication in new window or tab >>Essential improvements in future district heating systems
2017 (English)In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 116, p. 217-225Article in journal (Refereed) Published
Abstract [en]

The major common denominator for future efficient fourth generation district heating systems is lower temperature levels in the distribution networks. Higher efficiencies are then obtained in both heat supply and heat distribution. Heat supply becomes more efficient with respect to combined heat and power, flue gas condensation, heat pumps, geothermal extraction, low temperature excess heat, and heat storage. Heat distribution becomes more efficient from lower distribution losses, less pipe expansion, lower scalding risks, and plastic pipes. The lower temperature levels will be possible since future buildings will have lower temperature demands when requiring lower heat demands. This paper aims at providing seven essential recommendations concerning design and construction strategies for future fourth generation systems. The method used is based on a critical examination of the barriers for lower temperature levels and the origins of high return temperatures in contemporary third generation systems. The two main research questions applied are: Which parts of contemporary system design are undesirable? Which possible improvements are desirable? Key results and the corresponding recommendations include temperature levels for heat distribution, recirculation, metering, supervision, thermal lengths for heat exchangers and heat sinks, hydronic balancing, and legionella. The main conclusion is that it should be possible to construct new fourth generation district heating networks according to these seven essential recommendations presented in this paper. © 2017 The Authors. Published by Elsevier

Place, publisher, year, edition, pages
Amsterdam: Elsevier, 2017
Keywords
Low-temperature, System design, Recirculation, Thermal lengths, Hydronic balancing
National Category
Energy Engineering
Identifiers
urn:nbn:se:hh:diva-35278 (URN)10.1016/j.egypro.2017.05.069 (DOI)000406743000020 ()2-s2.0-85028617932 (Scopus ID)
Conference
The 15th International Symposium on District Heating and Cooling, , Seoul, Republic of Korea (South Korea), September 4-7, 2016
Projects
Future District Heating Technology
Note

Funding: Fjärrsyn – the Swedish district heating research programme funded in collaboration by the Swedish Energy Agency and the Swedish District heating Association

Available from: 2017-10-27 Created: 2017-10-27 Last updated: 2018-10-29Bibliographically approved
Averfalk, H. & Werner, S. (2017). Framtida fjärrvärmeteknik: Möjligheter med en fjärde teknikgeneration. Stockholm: Energiforsk
Open this publication in new window or tab >>Framtida fjärrvärmeteknik: Möjligheter med en fjärde teknikgeneration
2017 (English)Report (Refereed)
Place, publisher, year, edition, pages
Stockholm: Energiforsk, 2017. p. 62
Series
Energiforsk-Fjärrsyn rapport ; 419
National Category
Energy Engineering
Identifiers
urn:nbn:se:hh:diva-35277 (URN)978-91-7673-419-3 (ISBN)
Available from: 2017-10-27 Created: 2017-10-27 Last updated: 2017-11-02Bibliographically approved
David, A., Vad Mathiesen, B., Averfalk, H., Werner, S. & Lund, H. (2017). Heat Roadmap Europe: Large-Scale Electric Heat Pumps in District Heating Systems. Energies, 10(4), Article ID 578.
Open this publication in new window or tab >>Heat Roadmap Europe: Large-Scale Electric Heat Pumps in District Heating Systems
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2017 (English)In: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 10, no 4, article id 578Article in journal (Refereed) Published
Abstract [en]

The Heat Roadmap Europe (HRE) studies estimated a potential increase of the district heating (DH) share to 50% of the entire heat demand by 2050, with approximately 25–30% of it being supplied using large-scale electric heat pumps. This study builds on this potential and aims to document that such developments can begin now with technologies currently available. We present a database and the status of the technology and its ability of expansion to other European locations by reviewing experiences aimed at further research or application in the heating industry. This is based on a survey of the existing capacity of electric large-scale heat pumps with more than 1 MW thermal output, operating in European DH systems. The survey is the first database of its kind containing the technical characteristics of these heat pumps, and provides the basis for the analysis of this paper. By quantifying the heat sources, refrigerants, efficiency and types of operation of 149 units with 1580 MW of thermal output, the study further uses this data to analyze if the deployment of this technology on a large-scale is possible in other locations in Europe. It finally demonstrates that the technical level of the existing heat pumps is mature enough to make them suitable for replication in other locations in Europe.

Place, publisher, year, edition, pages
Basel: MDPI, 2017
Keywords
large-scale electric heat pumps, district heating, waste heat, sewage water, natural refrigerants, energy system flexibility
National Category
Energy Engineering
Identifiers
urn:nbn:se:hh:diva-34438 (URN)10.3390/en10040578 (DOI)000400065000167 ()2-s2.0-85028960455 (Scopus ID)
Available from: 2017-06-29 Created: 2017-06-29 Last updated: 2018-03-23Bibliographically approved
Averfalk, H., Ingvarsson, P., Persson, U., Gong, M. & Werner, S. (2017). Large heat pumps in Swedish district heating systems. Renewable & sustainable energy reviews, 79, 1275-1284
Open this publication in new window or tab >>Large heat pumps in Swedish district heating systems
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2017 (English)In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 79, p. 1275-1284Article in journal (Refereed) Published
Abstract [en]

Power-to-heat solutions like heat pumps and electric boilers are foreseen to be possible future tools to stabilise international power markets with high proportions of variable power supply. Temporary low cost electricity can be used for heat generation at times with high availability of wind and solar power through substitution of ordinary heat supply, hence contributing to increased energy system sustainability. Power-to-heat installations in district heating systems are competitive due to low specific investment and installation costs for large electric boilers, heat pumps, and heat storages. Several large-scale heat pumps were installed in Swedish district heating systems during the 1980s, since a national electricity surplus from new nuclear power existed for some years. The aim of this paper is to summarise the accumulated operation experiences from these large Swedish heat pumps to support and facilitate planning of future power-to-heat solutions with heat pumps in district heating systems. Gained experiences consider; installed capacities, capacity utilisation, heat sources used, refrigerant replacements, refrigerant leakages, and wear of mechanical components. The major conclusion is that many of the large thirty-year-old heat pumps are still in operation, but with reduced capacity utilisation due to internal competition from waste and biomass cogeneration plants in the district heating systems.

Place, publisher, year, edition, pages
Kidlington: Pergamon Press, 2017
Keywords
Power-to-heat, Heat pumps, District heating, District cooling, Integrated energy systems
National Category
Energy Systems
Identifiers
urn:nbn:se:hh:diva-34097 (URN)10.1016/j.rser.2017.05.135 (DOI)000410011500091 ()2-s2.0-85019691543 (Scopus ID)
Available from: 2017-06-13 Created: 2017-06-13 Last updated: 2019-04-04Bibliographically approved
Projects
Future district heating technology [P41302-1_Energi]; Halmstad University
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-2885-0923

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