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Rohdin, Patrik
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Blomqvist, S., Amiri, S., Rohdin, P. & Ödlund, L. (2019). Analyzing the Performance and Control of a Hydronic Pavement System in a District Heating Network. Energies, 12(11), Article ID 2078.
Open this publication in new window or tab >>Analyzing the Performance and Control of a Hydronic Pavement System in a District Heating Network
2019 (English)In: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 12, no 11, article id 2078Article in journal (Refereed) Published
Abstract [en]

A hydronic pavement system (HPS) is an alternative method to clear snow and ice, which avoids the use of salt, sand, and fossil fuel in conventional snow clearance, and minimizes the risk of accidents. The aim is to analyze the performance of different control strategies for a 35,000 m2 HPS utilizing heat from a district heating and cooling (DHC) system. The key performance indicators are (1) energy performance of the HPS, and (2) primary energy use, (3) electricity production and (4) greenhouse gas (GHG) emissions from the DHC system. The methodology uses a simulation model of the HPS and an optimization model of the DHC system. Three operational strategies are analyzed: A reference scenario based on the current control strategy, and scenarios where the HPS is shut down at temperatures below −10 °C and −5 °C. The study shows that the DHC return temperature is suitable for use. By operational strategies, use during peak demand in the DHC system can be avoided, resulting in reduced use of fossil fuel. Moreover, the energy use of the HPS could be reduced by 10% and the local GHG emissions by 25%. The study emphasizes that the HPS may have positive effects on global GHG emissions, as it enables electricity production from renewable resources.

Place, publisher, year, edition, pages
Basel: MDPI, 2019
National Category
Energy Systems Energy Engineering
Identifiers
urn:nbn:se:liu:diva-157189 (URN)10.3390/en12112078 (DOI)
Available from: 2019-06-04 Created: 2019-06-04 Last updated: 2019-06-04Bibliographically approved
Thollander, P., Karlsson, M., Rohdin, P. & Rosenqvist, J. (2019). Energieffektivisering: Energikartläggning, energiledning och styrmedel (1:1ed.). Lund: Studentlitteratur AB
Open this publication in new window or tab >>Energieffektivisering: Energikartläggning, energiledning och styrmedel
2019 (Swedish)Book (Other academic)
Abstract [sv]

Effektiv energianvändning i svensk tillverkningsindustri är en nyckelfaktor för att svenska företag, branscher och industrin som helhet även fortsättningsvis ska vara konkurrenskraftiga på en global marknad med knappare resurser. Denna bok är ett led i den riktningen.



Boken är uppdelad i tre delar: Del I har sin utgångspunkt i energi­effektiviseringsgapet och fokuserar på energikartläggning och energieffektivisering av företag, framför allt ur ett tekniskt perspektiv. Del II har sin utgångspunkt i energiledningsgapet och fokuserar på energiledning samt hinder och incitament för energieffektivisering i svensk tillverkningsindustri. Del III har sin utgångspunkt i styrmedelsgapet och inriktas mot styrmedel för energieffektivisering och hur dessa kan designas, implementeras och utvärderas. 


De två första delarna riktar sig framför allt till studenter vid svenska läro­­säten samt till energi- och miljöansvariga, teknikkonsulter, kommunala tillsynstjänstemän och andra offentliga aktörer vid exempelvis regionala energikontor. Del III riktar sig i första hand till aktörer som administrerar och ansvarar för styrmedel på nationell, regional och lokal nivå. Denna del kan även vara till nytta för koncerner som vill ta ett helhetsgrepp på energifrågan samt till företag som vill minska energianvändningens negativa miljöpåverkan i hela värdekedjan, inklusive underleverantörer.

Place, publisher, year, edition, pages
Lund: Studentlitteratur AB, 2019. p. 248 Edition: 1:1
Keywords
Energikartläggning, energiledning, styrmedel, industri, energianvändning, hinder och drivkrafter, energiprogram, enhetsprocess, energilära
National Category
Energy Engineering
Identifiers
urn:nbn:se:liu:diva-156662 (URN)9789144092478 (ISBN)
Available from: 2019-05-06 Created: 2019-05-06 Last updated: 2019-05-06Bibliographically approved
Blomqvist, S., La Fleur, L., Amiri, S., Rohdin, P. & Ödlund (Trygg), L. (2019). The Impact on System Performance When Renovating a Multifamily Building Stock in a District Heated Region. Sustainability, 11(8), Article ID 2199.
Open this publication in new window or tab >>The Impact on System Performance When Renovating a Multifamily Building Stock in a District Heated Region
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2019 (English)In: Sustainability, ISSN 2071-1050, E-ISSN 2071-1050, Vol. 11, no 8, article id 2199Article in journal (Other academic) Published
Abstract [en]

In Sweden, 90% of multifamily buildings utilize district heat and a large portion is in need of renovation. The aim is to analyze the impact of renovating a multifamily building stock in a district heating and cooling system, in terms of primary energy savings, peak power demands, electricity demand and production, and greenhouse gas emissions on local and global levels. The study analyzes scenarios regarding measures on the building envelope, ventilation, and substitution from district heat to ground source heat pump. The results indicate improved energy performance for all scenarios, ranging from 11% to 56%. Moreover, the scenarios present a reduction of fossil fuel use and reduced peak power demand in the district heating and cooling system ranging from 1 MW to 13 MW, corresponding to 4–48 W/m2 heated building area. However, the study concludes that scenarios including a ground source heat pump generate significantly higher global greenhouse gas emissions relative to scenarios including district heating. Furthermore, in a future fossil-free district heating and cooling system, a reduction in primary energy use will lead to a local reduction of emissions along with a positive effect on global greenhouse gas emissions, outperforming measures with a ground source heat pump.

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
district heating, multifamily buildings, renovation, primary energy use, energy system modeling, greenhouse gas emissions
National Category
Energy Systems
Identifiers
urn:nbn:se:liu:diva-157080 (URN)10.3390/su11082199 (DOI)000467752200012 ()2-s2.0-85065422245 (Scopus ID)
Available from: 2019-05-27 Created: 2019-05-27 Last updated: 2019-06-03Bibliographically approved
Blomqvist, S., Rohdin, P. & Ödlund, L. (2018). Hållbar Region: Ett forskningsprojekt för ökad samverkan mellan energi- och fastighetsbolag. Etapp 2 2016-2018. Linköping: Linköping University Electronic Press
Open this publication in new window or tab >>Hållbar Region: Ett forskningsprojekt för ökad samverkan mellan energi- och fastighetsbolag. Etapp 2 2016-2018
2018 (Swedish)Report (Other academic)
Abstract [sv]

Det är i samverkan mellan energibolag och slutanvändare som effektiva energisystem kan skapas. Med ett systemperspektiv mellan tillförsel- och användarsidan inom energisystemet kan forskningsprojektet Hållbar Region bidra med en pusselbit till framtidens energisystem, med ökad energieffektivitet och minskad klimatpåverkan som resultat.

Forskningsprojektets syfte är att genom samverkan mellan universitet, energi- och fastighetsbolag arbeta för att skapa en hållbar och resurseffektiv region. Detta delvis genom att utbyta kunskap kring utmaningar och på så vis öka förståelsen för varandras verksamheter, både inom och mellan branscherna.

Under etapp 1 utvecklades simulerings- och optimeringsmodeller gällande renoveringspaket av fastigheter och energisystemet. Arbetet fortskrider löpande med ytterligare beräkningar och scenarioanalyser. Under etapp 2 har många delstudier genomförts och som vardera ger input och kunskap för vidare utveckling. Några av resultaten uppkomna under etapp 2 är:

Betong bättre än trä?

En fallstudie påvisar att ett flerbostadshus med betongstomme har lägre miljöpåverkan än en liknande huskropp av träkonstruktion. Se mer i avsnitt 5.1

Vikten av utökad och förbättrad kundkontakt!

En studie av den framtida värmemarknaden visar på vikande efterfrågan. Nya tillämpningsområden, ökad och förbättrad kommunikation är viktiga aspekter för att möta utmaningen. Se mer i avsnitt 5.2

Tillvarata överskottsvärme!

Studien undersöker alternativ för att nyttiggöra överskottsvärme i fjärrvärmenätet, som möjliggörs genom samarbete med närliggande verksamheter. Att nyttogöra värmen genom en absorptionsdriven värmepump är det som förordas. Se mer i avsnitt 5.3

Beräkningar av primärenergifaktorer!

En studie analysera premiärenergifaktorer för svensk fjärrvärme utifrån flertalet perspektiv och metoder. De beräknade faktorerna blir betydande mindre än Boverkets. Se mer i avsnitt 5.4

Prismodellens roll för incitament till energieffektivisering!

Flertalet prismodeller analyseras utifrån ett klimatperspektiv. En modell med säsongsvarierande prissättning förordas och där effektuttaget lyfts fram som en nyckel. Se mer i avsnitt 5.5

Nyttan av en dynamisk framledningstemperatur!

Studien undersöker effekt- och flödesutjämnande körstrategier för att möta dygns- och säsongsvariationer av efterfrågan på värme. Studien påvisar ökad elverkningsgrad och ett högre temperaturspann möjliggör bättre effekt- och flödesutjämning. Se mer i avsnitt 5.6

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2018. p. 29
Keywords
Hållbar region, energisystem, samverkan, energibolag, fastighetsbolag, systemperspektiv, fjärrvärme, simulering, optimering, scenarioanalys
National Category
Energy Systems
Identifiers
urn:nbn:se:liu:diva-153481 (URN)
Projects
Hållbar Region
Note

Delrapport 2 från forskningsprojektet Hållbar Region vid Linköpings universitet.

Available from: 2018-12-19 Created: 2018-12-19 Last updated: 2018-12-20Bibliographically approved
Molin, A., Schneider, S., Rohdin, P. & Moshfegh, B. (2016). Assessing a regional building applied PV potential - Spatial and dynamic analysis of supply and load matching. Renewable energy, 91, 261-274
Open this publication in new window or tab >>Assessing a regional building applied PV potential - Spatial and dynamic analysis of supply and load matching
2016 (English)In: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 91, p. 261-274Article in journal (Refereed) Published
Abstract [en]

Electricity production by PV is growing world-wide, and grid parity of PV-electricity can be found in many countries, even in low sunlight countries, such as Sweden (at latitude 58 degrees). High installation-rate of PV-systems poses a challenge to the grid-operator. Building-integrated PV-supply potential analysis was performed for Linkoping municipality in Sweden based on GIS-data for all the buildings in the municipality. The Linkoping model provides a high spatial resolution (>180 000 buildings). The data are sorted based on azimuth and tilt, categorized in steps of 10 degrees, and then used to construct hourly power supply data. The supply data are fed into the existing electricity load-profile of Linkoping municipality. The strength and novelty of the method is that it provides the possibility of varying the installation-rate in different spatial directions to better match the load-profile. The results indicate a solar supply-rate of 19, 43 and 88% respectively if using the tilted roofs (>900 kWh/m(2) x yr), the flat-roofs optimized with tilted panels for a winter solar supply and the fully available PV-area on existing buildings (8.1 km(2)). Nevertheless, in approximately 70,1400 and >3000 h/yr, respectively, surplus-power is created, which could be used to match a future load in a wider electromobility scenario. (C) 2016 Elsevier Ltd. All rights reserved.

Place, publisher, year, edition, pages
PERGAMON-ELSEVIER SCIENCE LTD, 2016
Keywords
PV system; Dynamic load matching; Load profile; Self-consumption; Spatial-time distribution; Regional PV potential
National Category
Mechanical Engineering
Identifiers
urn:nbn:se:liu:diva-127250 (URN)10.1016/j.renene.2016.01.084 (DOI)000372382800025 ()
Note

Funding Agencies|Energy Systems Program; Swedish Energy Agency; Swedish Radiation Protection Authority; Swedish Environmental Agency

Available from: 2016-04-20 Created: 2016-04-19 Last updated: 2018-03-19Bibliographically approved
Svensson, K., Rohdin, P. & Moshfegh, B. (2016). On the influence of array size and jet spacing on jet interactions and confluence in round jet arrays. Journal of Fluids Engineering - Trancactions of The ASME, 138(8), Article ID 081206.
Open this publication in new window or tab >>On the influence of array size and jet spacing on jet interactions and confluence in round jet arrays
2016 (English)In: Journal of Fluids Engineering - Trancactions of The ASME, ISSN 0098-2202, E-ISSN 1528-901X, Vol. 138, no 8, article id 081206Article in journal (Refereed) Published
Abstract [en]

Arrays of unconfined confluent round jets exist in a number of engineering applications, including ventilation supply devices, sewage disposal systems, combustion burners, chemical mixing, and chimney stacks. Interacting confluent round jets are also interesting from a purely scientific point of view, as jet interactions and confluence bring additional complexity to the flow field. Yet little scientific attention has been paid to unconfined confluent round jets and detailed scientific investigations are scarce.

The present work uses computational models to study the effects of confluence and jet-to-jet interactions in four different confluent jet arrangements, reporting on the influence of jet array size and dimensionless jet spacing, 𝑆⁄𝑑0. The results show that both jet spacing and jet array size largely influence the jet-to-jet interactions and flow field development in confluent jet arrays. The jet interactions in the investigated setups result in regions of negative static pressure between jets, jet deformation, high spanwise velocity and jet displacement. Generally smaller jet spacing and larger array size results in stronger influence of jet interactions.

After the jets have combined the confluent jets form a zone with constant maximum streamwise velocity and decay of turbulence intensity, called a Confluent Core Zone (CCZ). During the CCZ the combined jet will have asymmetric spreading rates leading to axisswitching. The entrainment rate of the CCZ is constant, but the volumetric flow of the combined jet is substantially affected by the degree of entrainment before the jets have combined.

Keywords
Computational Fluid Dynamics (CFD), Confluent jets, Confluent Core Zone (CCZ), Jet interactions, Axis-switching.
National Category
Energy Systems
Identifiers
urn:nbn:se:liu:diva-117079 (URN)10.1115/1.4033024 (DOI)000379589700012 ()
Note

Vid tiden för disputation förelåg publikationen som manuskript

Funding agencies:The authors gratefully acknowledge the financial support received from the Swedish Research Council (Grant No. 2008-31145-61023-37) and Linkoping University (Sweden). The National Supercomputer Centre (NSC) is acknowledged for providing computational resources. The authors thank Dr. Mark Tummers, Delft University of Technology, and Ph.D. student Shahriar Ghahremanian, Linkoping University, for the fruitful cooperation when conducting the experimental work used for validation.

Available from: 2015-04-15 Created: 2015-04-15 Last updated: 2017-12-04Bibliographically approved
Svensson, K., Rohdin, P. & Moshfegh, B. (2015). A computational parametric study on the development of confluent round jet arrays. European journal of mechanics. B, Fluids, 53, 129-147
Open this publication in new window or tab >>A computational parametric study on the development of confluent round jet arrays
2015 (English)In: European journal of mechanics. B, Fluids, ISSN 0997-7546, E-ISSN 1873-7390, Vol. 53, p. 129-147Article in journal (Refereed) Published
Abstract [en]

In this study, Computational Fluid Dynamics (CFD) and response surface methodology is employed in a parametrical investigation of an in-line array of confluent round jets. Confluent round jet arrays are common within several fields of engineering, as detailed knowledge of the flow field development of confluent round jets is of great importance to design engineers working with, for example, chemical mixing, multiple jet burners, waste water disposal systems or ventilation supply devices. In this paper, five independent factors affecting flow field development are investigated with a multi-variable approach using a Box–Behnken design method.

The results include decay of maximum velocity, turbulence intensity, location of merging and combined points and development of volumetric flow rate. Dimensionless nozzle spacing, S/d0S/d0, is an important design parameter and has a large impact on several properties, such as merging and combined points, decay of maximum velocity, and development of turbulence intensity. Other factors, such as the number of jets per row and inlet velocity, are also of importance. The analysis of decay in maximum velocity led to the definition of a new zone of development, referred to as the Confluent Core Zone (CCZ), as its behaviour is reminiscent of the potential core of a single jet. The CCZ has uniform velocity, lacks considerable decay in streamwise velocity and has a rather low turbulence intensity. The CCZ has a characteristic footprint in confluent round jet arrays, and its properties are investigated in detail.

The development of volumetric flow can be divided into two regions. The initial region, close to the nozzles, features a high entrainment but decreasing entrainment rate. As the jets combine, the entrainment rate is lower, but rather constant. While S/d0S/d0 is generally an important design parameter, there is no direct correlation between S/d0S/d0 and entrainment rate of the combined jet.

Place, publisher, year, edition, pages
Elsevier, 2015
Keywords
Multiple jet array, Confluent jets, Computational Fluid Dynamics (CFD), Response Surface Methodology, Box-Behnken, Confluent Core Zone (CCZ)
National Category
Energy Systems
Identifiers
urn:nbn:se:liu:diva-117078 (URN)10.1016/j.euromechflu.2015.03.012 (DOI)000358968500012 ()
Available from: 2015-04-15 Created: 2015-04-15 Last updated: 2017-12-04Bibliographically approved
Thollander, P., Kimura, O., Wakabayashi, M. & Rohdin, P. (2015). A review of industrial energy and climate policies in Japan and Sweden with emphasis towards SMEs. Renewable & sustainable energy reviews, 50, 504-512
Open this publication in new window or tab >>A review of industrial energy and climate policies in Japan and Sweden with emphasis towards SMEs
2015 (English)In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 50, p. 504-512Article, review/survey (Refereed) Published
Abstract [en]

The threat of increased global warming resulting from the use of fossil fuels stresses decision-makers to formulate and adopt policies towards different sectors of the economy. In light of the great earthquake in Japan 2011, energy efficiency also plays an important role in meeting the challenge of power supply shortage. Energy policies towards industry are of particular importance as a major part of the energy in the economy is used in industrial production. The number of papers investigating and presenting experience from energy end-use policies are scarce. Furthermore, for those present, they often only include a very brief analysis. From a public point of view, evaluations of energy programs are of major importance to measure the performance of the programs. From an energy policy designer point of view, it is of major importance to not only see the cost-effectiveness of the policy but also to understand the fundamental mechanisms for the success or failure of an industrial energy program, in order to learn how to improve future programs. The aim of this paper is to present a review of energy end-use policy instrument in Japan and Sweden towards the industrial sector from 1990 to 2014, with special emphasis on industrial SMEs. From the results presented some general-conclusions can be made, (1) results show that the cost-effectiveness differs substantially between the evaluated programs, and (2) that from a governmental point of view, subsidies towards energy audit programs seem like the most cost-effective policy. In addition to this (3) the results from the review also stress the importance of a clear strategy for every energy program on how the program is going to be evaluated, ex-ante or ex-post, and how the performance of the program is to be measured. This structure should be included from the start of the program. (C) 2015 Elsevier Ltd. All rights reserved.

Place, publisher, year, edition, pages
Elsevier, 2015
Keywords
Energy end-use; Policy instrument; Industry; SME; Energy efficiency
National Category
Mechanical Engineering
Identifiers
urn:nbn:se:liu:diva-121094 (URN)10.1016/j.rser.2015.04.102 (DOI)000358968000036 ()
Note

Funding Agencies|Scholarship Foundation for Studies of Japanese Society; Environmental Policy Office; Industrial Science and Technology Policy and Environment Bureau of METI; Ministry of Economy, Trade and Industry of Japan; Swedish Energy Agency [35488-1]

Available from: 2015-09-07 Created: 2015-09-07 Last updated: 2017-12-04
Liu, L., Rohdin, P. & Moshfegh, B. (2015). Evaluating indoor environment of a retrofitted multi-family building with improved energy performance in Sweden. Energy and Buildings, 102, 32-44
Open this publication in new window or tab >>Evaluating indoor environment of a retrofitted multi-family building with improved energy performance in Sweden
2015 (English)In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 102, p. 32-44Article in journal (Refereed) Published
Abstract [en]

The building sector within both the EU and Sweden accounts for about 40% of total energy use. It is therefore important to introduce energy efficiency measures in this sector in order to meet the national implementation of the Building Performance Directive. Retrofits that result in improved energy performance are important in order to meet national energy targets, but the impact on the indoor environment has to be considered. Properly chosen energy efficiency measures may affect the indoor environment positively. One retrofitted multi-family building, located in the city of Linkoping, Sweden, was chosen as the study object. The building represents a common type of construction in Sweden. This study presents an evaluation of both the indoor environment and energy use of the retrofitted building in comparison with a similar non-retrofitted building from the same area. The results show that the building has potential to reach a 39% reduction of space heating demand. The indoor environment has been improved compared to the non-retrofitted building. Adding external blinds from 15 May to 15 September between 10am-12pm on the east side and 12pm-3pm on the west side seems to be the best option for improving the indoor climate during summer. (c) 2015 Elsevier B.V. All rights reserved.

Place, publisher, year, edition, pages
Elsevier, 2015
Keywords
Multi-family building; Retrofit; Building energy simulation; Energy use; Indoor environment
National Category
Mechanical Engineering
Identifiers
urn:nbn:se:liu:diva-120720 (URN)10.1016/j.enbuild.2015.05.021 (DOI)000358458100003 ()
Note

Funding Agencies|Swedish Energy Agency

Available from: 2015-08-24 Created: 2015-08-24 Last updated: 2017-12-04
Joudi, A., Cehlin, M., Svedung, H., Rohdin, P. & Moshfegh, B. (2015). Influence of reflective interior surfaces on indoor thermal environment and energy use using a coupling model for energy simulation and CFD.
Open this publication in new window or tab >>Influence of reflective interior surfaces on indoor thermal environment and energy use using a coupling model for energy simulation and CFD
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2015 (English)Manuscript (preprint) (Other academic)
Abstract [en]

The importance of reducing the building energy use and maintaining the desired indoor climate has long inspired creative solution such as optimized optical properties for building surfaces. This paper aims to address the influence of interior thermal reflective surfaces on both indoor thermal environments with high spatial resolution and energy use. To do so, this work employs a coupling method using building energy simulation (BES) and computational fluid dynamics (CFD). The results indicate increase in the mean radiation temperature (MRT) and reduction in the floor heating energy use by the use of interior reflective surfaces. The study yields analysis of operative temperatures and interior surface heat fluxes. Overall, the interior reflective surfaces can contribute to improved building thermal performance and energy saving.

Keywords
Thermal reflective surfaces, mean radiation temperature, building thermal performance, coupling building energy simulation and CFD
National Category
Energy Systems Building Technologies
Identifiers
urn:nbn:se:liu:diva-118290 (URN)
Available from: 2015-05-25 Created: 2015-05-25 Last updated: 2015-05-26Bibliographically approved
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