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  • 1.
    Aboudi, U
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Altaie, K
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Solvärme i krypgrunder2009Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • 2.
    Aboudi, Ula
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Altaie, Kenan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Solvärme för krypgrunder2008Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • 3.
    Adolfsson, J
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Lu, W
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Fossilbränslefri uppvärmning i Norra Djurgårdsstaden år 20302009Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • 4.
    Albazi, A
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Driftteknisk/-ekonomisk analys av FX och FTX system i ett referenshus2008Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • 5.
    Alsmo, Thomas
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Holmberg, Sture
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    A Study of Sources of Airborne Pollutants and Poor Hygiene in Schools2010In: Indoor + Built Environment, ISSN 1420-326X, E-ISSN 1423-0070, Vol. 19, no 2, p. 298-304Article in journal (Refereed)
    Abstract [en]

    Poor indoor air quality is a large problem in Swedish schools, since the health of occupants may be affected. Resources are consumed without identification of utility indicators and there is risk of problems, even after remedial measures have been taken. This can mean both unnecessary suffering for many people and considerable resources being wasted. The building itself is often in focus and other building-related problems may be neglected. The hypothesis of the present work is that other factors than the building itself have decisive influence on indoor air quality. An assessment of these nonbuilding-related reasons for bad indoor air quality has been made in the present study using particle measurements. Results show that it is possible to decrease emissions in indoor air by over 90% through identifying and eliminating activity-related sources of airborne contaminants.

  • 6. Alsved, M.
    et al.
    Civilis, A.
    Ekolind, P.
    Tammelin, A.
    Andersson, A. Erichsen
    Jakobsson, J.
    Svensson, T.
    Ramstorp, M.
    Sadrizadeh, Sasan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology. Lawrence Berkeley Natl Lab, Berkeley, CA USA.
    Larsson, P-A
    Bohgard, M.
    Santl-Temkiv, T.
    Londahl, J.
    Temperature-controlled airflow ventilation in operating rooms compared with laminar airflow and turbulent mixed airflow2018In: Journal of Hospital Infection, ISSN 0195-6701, E-ISSN 1532-2939, Vol. 98, no 2, p. 181-190Article in journal (Refereed)
    Abstract [en]

    Aim: To evaluate three types of ventilation systems for operating rooms with respect to air cleanliness [in colony-forming units (cfu/m(3))], energy consumption and comfort of working environment (noise and draught) as reported by surgical team members. Methods: Two commonly used ventilation systems, vertical laminar airflow (LAF) and turbulent mixed airflow (TMA), were compared with a newly developed ventilation technique, temperature-controlled airflow (T(c)AF). The cfu concentrations were measured at three locations in an operating room during 45 orthopaedic procedures: close to the wound (<40 cm), at the instrument table and peripherally in the room. The operating team evaluated the comfort of the working environment by answering a questionnaire. Findings: LAF and T(c)AF, but not TMA, resulted in less than 10 cfu/m(3) at all measurement locations in the room during surgery. Median values of cfu/m(3) close to the wound (250 samples) were 0 for LAF, 1 for T(c)AF and 10 for TMA. Peripherally in the room, the cfu concentrations were lowest for T(c)AF. The cfu concentrations did not scale proportionally with airflow rates. Compared with LAF, the power consumption of T(c)AF was 28% lower and there was significantly less disturbance from noise and draught. Conclusion: T(c)AF and LAF remove bacteria more efficiently from the air than TMA, especially close to the wound and at the instrument table. Like LAF, the new T(c)AF ventilation system maintained very low levels of cfu in the air, but T(c)AF used substantially less energy and provided a more comfortable working environment than LAF. This enables energy savings with preserved air quality.

  • 7. Alsved, Malin
    et al.
    Wang, Cong
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Civilis, Anette
    Sadrizadeh, Sasan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Ekolind, Peter
    Skredsvik, Henrik
    Höjerback, Peter
    Jakobsson, Jonas
    Löndahl, Jakob
    Experimental and computational evaluation of airborne bacteria in hospital operating rooms with high airflows2018In: Proceedings of The 5th Working & Indoor Aerosols Conference 18-20 April 2018; Cassino, Italy, 2018Conference paper (Refereed)
    Abstract [en]

    Post-operative infections after surgery can be decreased by the use of efficient ventilation with clean air. In this study, we investigated three types of operating room ventilation: turbulent mixed airflow(TMA), laminar airflow (LAF) and a new type of ventilation named temperature controlled airflow(TcAF). Measurements of airborne bacteria were made during surgery and compared with values calculated by computational fluid dynamics (CFD). The results show that LAF and TcAF are most efficient in removing bacteria around the patient. With LAF, there are large differences in bacterial loads, depending on location in the room.

  • 8.
    Andersson, C
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Jacobsson, M
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    LCC-analys på energibesparande åtgärder i ventilationssystem2005Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • 9.
    Birchall, Sarah
    et al.
    BSRIA.
    Gustafsson, Marcus
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology. Högskolan Dalarna, Sweden.
    Wallis, Ian
    BSRIA.
    Dipasquale, Chiara
    EURAC.
    Bellini, Alessandro
    EURAC.
    Fedrizzi, Roberto
    EURAC.
    Survey and simulation of energy use in the European building stock2016Conference paper (Refereed)
    Abstract [en]

    Buildings account for around 40% of the final energy consumption in Europe and are central in the work towards increased energy efficiency. In order to plan and perform effective energy renovation of the buildings, it is necessary to have adequate information on the current status of the buildings in terms of architectural features and energy needs. Unfortunately, the official statistics do not include all of the needed information for the whole building stock.

     

    This paper aims to fill the gaps in the statistics by gathering data from studies, projects and national energy agencies, and by calibrating TRNSYS models against the existing data to complete missing energy demand data, for countries with similar climate, through simulation. The survey was limited to residential and office buildings in the EU member states (before July 2013). This work was carried out as part of the EU FP7 project iNSPiRe.

     

    The building stock survey revealed over 70% of the residential and office floor area is concentrated in the six most populated countries. The total energy consumption in the residential sector is 14 times that of the office sector. In the residential sector, single family houses represent 60% of the heated floor area, albeit with different share in the different countries, indicating that retrofit solutions cannot be focused only on multi-family houses.

     

    The simulation results indicate that residential buildings in central and southern European countries are not always heated to 20 °C, but are kept at a lower temperature during at least part of the day. Improving the energy performance of these houses through renovation could allow the occupants to increase the room temperature and improve their thermal comfort, even though the potential for energy savings would then be reduced.

  • 10.
    Buddgård, M
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Analys av åtgärder för energieffektivisering av Riksdagens byggnader2007Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • 11. Cao, Z.
    et al.
    Lei, L.
    Wang, Qian
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Fransson, Torsten
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Comparison study of the development of ethanol fuels in China2010In: 6th Advanced Forum on Transportation of China (AFTC 2010), 2010, no 573 CP, p. 150-154Conference paper (Refereed)
    Abstract [en]

    Based on the analysis of the producing principles of ethanol fuels for the vehicles and their development in the world,in the article the ethanol fuels is compared with conventional fuels in eight indicators covering economic, environment and producing technology by AHP model. The main objective of this research work is to study the difficulties and arising obstacles of promoting the ethanol fuel in Chinese market based on the calculation results, and finally propose appropriate solutions and new ideas to ease the energy crisis and traffic pollutions in China.

  • 12.
    Dahlman, S
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Tauberman, S
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Väggvärme – Framtidens värmesystem ?2007Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • 13.
    Dermentzis, Georgios
    et al.
    University of Innsbruck.
    Gustafsson, Marcus
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology. Högskolan Dalarna.
    Ochs, Fabian
    University of Innsbruck.
    Holmberg, Sture
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Feist, Wolfgang
    Passivhaus Institut.
    Calabrese, Toni
    University of Innsbruck.
    Oberrauch, Philipp
    University of Innsbruck.
    Evaluation of a versatile energy auditing tool2016Conference paper (Refereed)
    Abstract [en]

    Energy auditing can be an important contribution for identification and assessment of energy conservation measures (ECMs) in buildings. Numerous tools and software have been developed, with varying degree of precision and complexity and different areas of use.

     

    This paper evaluates PHPP as a versatile, easy-to-use energy auditing tool and gives examples of how it has been compared to a dynamic simulation tool, within the EU-project iNSPiRe. PHPP is a monthly balance energy calculation tool based on EN13790. It is intended for assisting the design of Passive Houses and energy renovation projects and as guidance in the choice of appropriate ECMs.

     

    PHPP was compared against the transient simulation software TRNSYS for a single family house and a multi-family house. It should be mentioned that dynamic building simulations might strongly depend on the model assumptions and simplifications compared to reality, such as ideal heating or real heat emission system. Setting common boundary conditions for both PHPP and TRNSYS, the ideal heating and cooling loads and demands were compared on monthly and annual basis for seven European locations and buildings with different floor area, S/V ratio, U-values and glazed area of the external walls.

     

    The results show that PHPP can be used to assess the heating demand of single-zone buildings and the reduction of heating demand with ECMs with good precision. The estimation of cooling demand is also acceptable if an appropriate shading factor is applied in PHPP. In general, PHPP intentionally overestimates heating and cooling loads, to be on the safe side for system sizing. Overall, the agreement with TRNSYS is better in cases with higher quality of the envelope as in cold climates and for good energy standards. As an energy auditing tool intended for pre-design it is a good, versatile and easy-to-use alternative to more complex simulation tools.

  • 14.
    Dharmakeerthi, M
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Byggmaterialval för en bättre inomhusmiljö- Riktlinjer för TVOC2008Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • 15.
    Dipasquale, Chiara
    et al.
    EURAC.
    Fedrizzi, Roberto
    EURAC.
    Bellini, Alessandro
    EURAC.
    Ochs, Fabian
    University of Innsbruck.
    Gustafsson, Marcus
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Bales, Chris
    Högskolan Dalarna, Energiteknik.
    Sié, Marion
    Cycleco.
    Energetic, economic and environmental analysis of energy renovation packages for residential and office building stock: methodologyManuscript (preprint) (Other academic)
    Abstract [en]

    The high energy consumption in the residential and office sectors requires the individuation of renovation solutions that can be widely applied on different building typologies and climates. Several tools and methodologies are nowadays available both for the assessment of building demands and for individuating the optimal retrofit solution, but usually they are not user-friendly or applicable to a cluster of buildings.

    In this context, this paper aims at describing a methodology developed to generate a matrix of solutions for typical building and HVAC systems in different climatic conditions. The results are collected in a database. The studied building typologies concern single family houses, multi-family houses and offices. Envelope renovation measures are firstly applied in order to reduce the building demands; afterwards, efficient HVAC systems are implemented. Air-to-water heat pump, ground source heat pump, condensing and pellet boilers are studied. The contribution of solar technologies, thermal panels and PV is also accounted for. Per building typology, climate and renovation package, the database reports energetic, economic and environmental indicators. The database is available on-line, it can be consulted by researchers or technicians of the retrofit sector for comparing different renovation packages and helping during the decision making process.

  • 16. Enze, Tian
    et al.
    Yulong, Chang
    Sadrizadeh, Sasan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Jinhan, Mo
    Afshari, Alireza
    Airborne Particles removal by Negative Ions Generated in Ambient Air and Inert Gas2017In: In: Proceedings of the 10th International Symposium on Heating, Ventilation and Air Conditioning – ISHVAC 2017. 19-22 2017; Jinan, China, 2017Conference paper (Refereed)
    Abstract [en]

    Airborne particles can be removed by air ions in enclosed environment, but the main drawback of this method is the formation of harmful by-products such as ozone (O3). In this study, we use ambient air and inert gas, including argon (Ar) and Nitrogen (N2) to generate negative ions respectively, and then release those ions into an enclosed chamber with ambient air. We then investigated the particle concentration decay rates and O3 concentration increase in the chamber. We found that the particle concentration decay rates were 0.343 min-1, 0.209 min-1 and 0.274 min-1 when ions were generated in ambient air, Ar and N2 respectively. The ozone concentration does not show a marked increase when using either ambient air or inert gas (Ar and N2) to generate ions. Since the temperature and humidity of ambient air may influence the ozone generation during ionizing, further study should be investigated.

  • 17.
    Erdemgur, U
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Mohamed, H
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Radon i flerbostadshus – mätningar och åtgärder2004Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • 18.
    Flodkvist, Å
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Lifvergren, L
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Stegvis integrering av solceller i byggnader2004Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • 19.
    Granroth, Marko
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    BIM - ByggnadsInformationsModellering: Orientering i modern arbetsmetod2011 (ed. 1)Book (Other academic)
    Abstract [sv]

    Ordet BIM används flitigt inom byggsektorn, ibland utan att man får en klar bild av vad det kan innebära. Olika företag och individer har under de senaste åren introducerat olika beskrivningar av vad en byggnadsinformationsmodell kan innehålla, och man har där blandat visioner och verklighet i en salig röra när olika uppfattningar har slagits ihop till en. Utan god insikt och förståelse för BIM är det svårt att se skillnaden mellan visioner och vad som är praktiskt möjligt idag, imorgon och några år framåt.En djupare förståelse för dessa förändringar kan man få genom teori i ämnet och med hjälp av förberedelser, genom att utvärdera tidigare BIM-projekt i omvärlden och sedan omvandla teorin till praktisk tillämpning. De flesta kommer att använda denna utvärderande arbetsmodell och några få kommer att bli branschens filosofer och visa vägen när det gäller hur dessa visioner ska kunna tillämpas i verkliga projekt. Andra kommer att förbli traditionalister - alla fyller vi en plats i byggprocessen.

  • 20.
    Granroth, Marko
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    BIM kräver en tidigare och låst tidsplanering: IT BIM2011In: Husbyggaren, ISSN 0018-7968, no 6, p. 36-37Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    IT BIM Tidsplanering av projekteringsskedet i BIM-projekt skiljer sig från traditionell planering på en väsentlig punkt. Gestaltning och systemval blir tidigt låsta. Möjligheten att påverka minskar och kostnaden blir hög vid förändringar. Detta måste respekteras.

  • 21.
    Granroth, Marko
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Design and Engineering Coordination using BIM2010Conference paper (Other academic)
  • 22.
    Granroth, Marko
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Modern metod gestaltar delprocesser i bygge: IT BIM2011In: husbyggaren, ISSN 0018-7968, no 4, p. 42-46Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Artikeln visar hur byggprocessen kan se ut om man ser, när man arbeter med moderna arbetsmetoder inom BIM.

  • 23.
    Gustafsson, Marcus
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Energy efficient and economic renovation of residential buildings with low-temperature heating and air heat recovery2015Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    With the building sector accounting for around 40% of the total energy consumption in the EU, energy efficiency in buildings is and continues to be an important issue. Great progress has been made in reducing the energy consumption in new buildings, but the large stock of existing buildings with poor energy performance is probably an even more crucial area of focus. This thesis deals with energy efficiency measures that can be suitable for renovation of existing houses, particularly low-temperature heating systems and ventilation systems with heat recovery. The energy performance, environmental impact and costs are evaluated for a range of system combinations, for small and large houses with various heating demands and for different climates in Europe. The results were derived through simulation with energy calculation tools.

    Low-temperature heating and air heat recovery were both found to be promising with regard to increasing energy efficiency in European houses. These solutions proved particularly effective in Northern Europe as low-temperature heating and air heat recovery have a greater impact in cold climates and on houses with high heating demands. The performance of heat pumps, both with outdoor air and exhaust air, was seen to improve with low-temperature heating. The choice between an exhaust air heat pump and a ventilation system with heat recovery is likely to depend on case specific conditions, but both choices are more cost-effective and have a lower environmental impact than systems without heat recovery. The advantage of the heat pump is that it can be used all year round, given that it produces DHW.

    Economic and environmental aspects of energy efficiency measures do not always harmonize. On the one hand, lower costs can sometimes mean larger environmental impact; on the other hand there can be divergence between different environmental aspects. This makes it difficult to define financial subsidies to promote energy efficiency measures.

  • 24.
    Gustafsson, Marcus
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology. Högskolan Dalarna.
    Energy Efficient Renovation Strategies for Swedish and Other European Residential and Office Buildings2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The high energy use in the European building stock is attributable to the large share of old buildings with poor energy performance. Energy renovation of buildings is therefore vital in the work towards energy efficiency and reduced environmental impact in the EU. Yet, the strategies and energy system implications of this work have not been made clear, and the rate of building renovation is currently very low.

    The aim of this thesis is to investigate the economic and environmental aspects of energy renovation strategies, with two main objectives:

    • Renovation of Swedish district heated multi-family houses, including life-cycle cost and environmental analysis and impact on the local energy system;

    • Renovation of European residential and office buildings, including life-cycle cost and environmental analysis and influence of climatic conditions.

    Buildings typical for the respective regions and the period of construction 1945-1970 were simulated, in order to determine the feasibility and energy saving potential of energy renovation measures in European climates. A variety of systems for heating, cooling and ventilation were studied, as well as solar energy systems, with focus on heat pumps, district heating, low-temperature heating systems and air heat recovery.

    Compared to normal building renovation, energy renovation can often reduce the life-cycle costs and environmental impact. In renovation of typical European office buildings, as well as Southern European multi-family houses, more ambitious renovation levels can also be more profitable.

    Exhaust air heat pumps can be cost-effective complements in district heated multi-family houses, while ventilation with heat recovery is more expensive but also more likely to reduce the primary energy use. From a system perspective, simple exhaust ventilation can reduce the primary energy use in the district-heating plant as much as an exhaust air heat pump, due to the lower electricity use.

  • 25.
    Gustafsson, Marcus
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology. Dalarna University, Sweden.
    Dipasquale, C.
    Poppi, Stefano
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. Högskolan Dalarna, Sverige.
    Bellini, A.
    Fedrizzi, R.
    Bales, C.
    Ochs, F.
    Sié, M.
    Holmberg, Sture
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Economic and environmental analysis of energy renovation packages for European office buildings2017In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 148, p. 155-165Article in journal (Refereed)
    Abstract [en]

    A large share of the buildings in Europe are old and in need of renovation, both in terms of functional repairs and energy efficiency. While many studies have addressed energy renovation of buildings, they rarely combine economic and environmental life cycle analyses, particularly for office buildings. The present paper investigates the economic feasibility and environmental impact of energy renovation packages for European office buildings. The renovation packages, including windows, envelope insulation, heating, cooling and ventilation systems and solar photovoltaics (PV), were evaluated in terms of life cycle cost (LCC) and life cycle assessment (LCA) through dynamic simulation for different European climates. Compared to a purely functional renovation, the studied renovation packages resulted in up to 77% lower energy costs, 19% lower total annualized costs, 79% lower climate change impact, 89% lower non-renewable energy use, 66% lower particulate matter formation and 76% lower freshwater eutrophication impact over a period of 30 years. The lowest total costs and environmental impact, in all of the studied climates, were seen for the buildings with the lowest heating demand. Solar PV panels covering part of the electricity demand could further reduce the environmental impact and, at least in southern Europe, even reduce the total costs.

  • 26.
    Gustafsson, Marcus
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Dipasquale, Chiara
    EURAC.
    Poppi, Stefano
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. Högskolan Dalarna.
    Bellini, Alessandro
    EURAC.
    Fedrizzi, Roberto
    EURAC.
    Bales, Chris
    Högskolan Dalarna, Energiteknik.
    Ochs, Fabian
    University of Innsbruck.
    Sié, Marion
    Cycleco.
    Holmberg, Sture
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Economic and environmental analysis of energy renovation measures for European office buildingsManuscript (preprint) (Other academic)
    Abstract [en]

    A large share of the buildings in Europe are old and in need of renovation, both in terms of functional repairs and energy efficiency. While many studies have addressed energy renovation of buildings, they rarely combine economic and environmental life cycle analyses, particularly for office buildings. The present paper investigates the economic feasibility and environmental impact of energy renovation packages for European office buildings. The renovation packages, including windows, envelope insulation, heating, cooling and ventilation systems and solar photovoltaics (PV), were evaluated in terms of life cycle cost (LCC) and life cycle assessment (LCA) through dynamic simulation for different European climates. Compared to a purely functional renovation, the studied renovation packages resulted in up to 77% lower energy costs, 19% lower total annualized costs, 79% lower climate change impact, 89% lower non-renewable energy use, 66% lower particulate matter formation and 76% lower freshwater eutrophication impact over a period of 30 years. The lowest total costs and environmental impact, in all of the studied climates, were seen for the buildings with the lowest heating demand. Solar PV panels covering part of the electricity demand could further reduce the environmental impact and, at least in southern Europe, even reduce the total costs.

  • 27.
    Gustafsson, Marcus
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology. Högskolan Dalarna.
    Myhren, Jonn Are
    Högskolan Dalarna.
    Bales, Chris
    Högskolan Dalarna.
    Comparison of two HVAC renovation solutions: A case study2013In: CLIMA 2013, Prague, June 16-19, 2013, 2013Conference paper (Refereed)
    Abstract [en]

    Within the aging building stock of Europe, there is great potential of saving energy through renovation and upgrading to modern standards, and to thereby approach the internationally set goals of lower energy use. This paper concerns the planned renovation of the building envelope and HVAC systems in a multi-family house in Ludwigsburg, Germany. Five systemic HVAC solutions were compared, with special focus on two systems: A) Balanced ventilation with HRC + Micro heat pump, and B) Forced exhaust ventilation + Heat pump with exhaust air HRC + Ventilation radiators. Given the predicted heating demand and ventilation rate of the house after renovation, the performance of the two systems was compared, alongside three common systems for reference. Calculations were made using TMF Energi, a tool developed by SP Technical Research Institute of Sweden.

    Both systems A and B were found to have the lowest electrical energy use together with the ground source heat pump system for the assumed conditions. For other assumptions, including different climate and degree of insulation, some differences between these three systems were noted. Most significant is the increased electrical use of system B for higher heating loads due to limitations in the power available from the heat source, exhaust air, which is dependent on the ventilation rate.

  • 28.
    Gustafsson, Marcus
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology. Dalarna University, Sweden.
    Swing Gustafsson, Moa
    Högskolan Dalarna, Energiteknik; Mälardalens Högskola.
    Myhren, Jonn Are
    Högskolan Dalarna, Byggteknik.
    Bales, Chris
    Högskolan Dalarna, Energiteknik.
    Holmberg, Sture
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Techno-economic analysis of energy renovation measures for a district heated multi-family house2016In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 177, p. 108-116Article in journal (Refereed)
    Abstract [en]

    Renovation of existing buildings is important in the work towards increased energy efficiency and reduced environmental impact. The present paper treats energy renovation measures for a Swedish district heated multi-family house, evaluated through dynamic simulation. Insulation of roof and façade, better insulating windows and flow-reducing water taps, in combination with different HVAC systems for recovery of heat from exhaust air, were assessed in terms of life cycle cost, discounted payback period, primary energy consumption, CO₂ emissions and non-renewable energy consumption. The HVAC systems were based on the existing district heating substation and included mechanical ventilation with heat recovery and different configurations of exhaust air heat pump.

    Compared to a renovation without energy saving measures, the combination of new windows, insulation, flow-reducing taps and an exhaust air a heat pump gave up to 24% lower life cycle cost. Adding insulation on roof and façade, the primary energy consumption was reduced by up to 58%, CO₂ emissions up to 65% and non-renewable energy consumption up to 56%. Ventilation with heat recovery also reduced the environmental impact but was not economically profitable in the studied cases. With a margin perspective on electricity consumption, the environmental impact of installing heat pumps or air heat recovery in district heated houses is increased. Low-temperature heating improved the seasonal performance factor of the heat pump by up to 11% and reduced the environmental impact.

  • 29.
    Hesaraki, Arefeh
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Energy and Indoor Environment in New Buildings with Low-Temperature Heating System2013Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The aim of this thesis was to evaluate new buildings with low-temperature heating systems in terms of energy consumption and thermal comfort, and to pay some attention to energy savings and indoor air quality. To reach this aim, on-site measurements as well as building energy simulations using IDA Indoor Climate and Energy (ICE) 4 were performed. Results show that the investigated buildings with low-temperature heating system could meet the energy requirements of Swedish regulations in BBR (Boverkets byggregler), as well as provide a good level of thermal comfort. Implementing variable air volume ventilation instead of constant flow, i.e. decreasing the ventilation air from 0.35 to 0.10 l·s-1·m-2 during the whole unoccupancy (10 hours), gave up to 23 % energy savings for heating the ventilation air. However, the indoor air quality was not acceptable because VOC (volatile organic compound) concentration was slightly above the acceptable range for one hour after occupants arrive home. So, in order to create acceptable indoor air quality a return back to the normal ventilation requirements was suggested to take place two hours before the home was occupied. This gave 20 % savings for ventilation heating. The results of this study are in line with the European Union 20-20-20 goal to increase the efficiency of buildings by 20 % to the year 2020.

  • 30.
    Hesaraki, Arefeh
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Low-Temperature Heating and Ventilation for Sustainability in Energy Efficient Buildings2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In 2013, the building sector consumed approximately 39 % of the total final energy use in Sweden. Energy used for heating and hot water was responsible for approximately 60 % of the total energy consumption in the building sector. Therefore, energy-efficient and renewable-based heating and ventilation systems have high potential for energy savings. The potentials studied in this thesis include the combination of a low-temperature heat emitter (supply temperature below 45 °C) with heat pump and/or seasonal thermal energy storage, and variable air volume ventilation system. The main aim of this thesis was to evaluate energy savings and indoor air quality when those energy-efficient and sustainable heating and ventilation systems were implemented in buildings. For this purpose, on-site measurements, lab tests, analytical models, and building energy simulation tool IDA Indoor Climate and Energy 4 were used.

    Annual on-site measurements for five new two-family houses with low- and very-low-temperature heat emitters connected to an exhaust air heat pump showed  that  between  45–51 kWh∙m-2 energy was used  to  produce  and transport supply water for space heating and domestic hot water. Statistical data showed that these values are 39–46 % lower compared to the energy requirement for the same usage  which is, 84 kWh∙m-2)  in  an  average Swedish new single- and two-family house.

    Annual on-site measurements for five new two-family houses with low- and very-low-temperature heat emitters connected to an exhaust air heat pump showed that between 45–51 kWh∙m-2 energy was used to produce and transport supply water for space heating and domestic hot water. Statistical data showed that these values are 39–46 % lower compared to the energy requirement for the same usage (which is, 84 kWh∙m-2) in an average Swedish new single- and two-family house.

    In order to compare the energy performance of very-low- and low-temperature heat emitters with medium-temperature heat emitters under the same condition, lab tests were conducted in a climate chamber facility at Technical University of Denmark (DTU). To cover the heat demand of 20 W·m-2 by active heating, measurements showed that the required supply water temperatures were 45 ºC for the conventional radiator, 33 ºC in ventilation radiator and 30 ºC in floor heating. This 12–15 ºC temperature reduction with ventilation radiator and floor heating resulted in 17–22 % savings in energy consumption compared to a reference case with conventional radiator.

    Reducing the supply temperature to the building’s heating system allows using more renewable and low-quality heat sources. In this thesis, the application of seasonal thermal energy storage in combination with heat pump in a building with very-low-, low-, and medium-temperature heat emitters was investigated. Analytical model showed that using a 250 m3 hot water seasonal storage tank connected to a 50 m2 solar collector and a heat pump resulted in 85–92 % of the total heat demand being covered by solar energy.

    In addition to the heating system, this thesis also looked at ventilation system in terms of implementing variable (low) air volume ventilation instead of a constant (high) flow in new and retrofitted old buildings. The analytical model showed that, for new buildings with high volatile organic compound concentration during initial years of construction, decreasing the ventilation rate to 0.1 L·s-1·m-2 during the entire un-occupancy period (from 8:00–18:00) creates unacceptable indoor air quality when home is occupied at  18:00.  So,  in  order  to  create  acceptable  indoor  air  quality  when  the occupants come home, a return to the normal ventilation requirements was suggested to take place two hours before the home was occupied. This eight- hour ventilation reduction produced savings of 20 % for ventilation heating and 30 % for electricity consumption by ventilation fan.

    In addition, the influence of different ventilation levels on indoor air quality and energy savings was studied experimentally and analytically in a single- family house occupied by two adults and one infant. Carbon dioxide (CO2) concentration as an indicator of indoor air quality was considered in order to find  appropriate  ventilation  rates.  Measurements  showed  that,  with  an 0.20 L∙s-1∙m-2  ventilation rate, the CO2   level  was always below 950 ppm, which shows that this level is sufficient for the reference building (CO2 lower than 1000 ppm is acceptable). Calculations showed that low ventilation rates of 0.20 L∙s1∙m-2 caused 43 % savings of the combined energy consumption for  ventilation  fan  and  ventilation  heating  compared  to  the  cases  with 0.35 L∙s-1∙m-2  as a normal ventilation rate recommended by BBR (Swedish Building Regulations).

     

  • 31.
    Hesaraki, Arefeh
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Bourdakis, Eleftherios
    Ploskic, Adnan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Holmberg, Sture
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Experimental study of energy performance in low-temperature hydronic heating systems2015In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 109, p. 108-114Article in journal (Other academic)
    Abstract [en]

    Energy consumption, thermal environment and environmental impacts were analytically and experimentally studied for different types of heat emitters. The heat emitters studied were conventional radiator, ventilation radiator, and floor heating with medium-, low-, and very-low-temperature supply, respectively. The ventilation system in the lab room was a mechanical exhaust ventilation system that provided one air change per hour of fresh air through the opening in the external wall with a constant temperature of 5 °C, which is the mean winter temperature in Copenhagen. The parameters studied in the climate chamber were supply and return water temperature from the heat emitters, indoor temperature, and heat emitter surface temperature. Experiments showed that the mean supply water temperature for floor heating was the lowest, i.e. 30 °C, but it was close to the ventilation radiator, i.e. 33 °C. The supply water temperature in all measurements for conventional radiator was significantly higher than ventilation radiator and floor heating; namely, 45 °C. Experimental results indicated that the mean indoor temperature was close to the acceptable level of 22 °C in all cases. For energy calculations, it was assumed that all heat emitters were connected to a ground-source heat pump. Analytical calculations showed that using ventilation radiator and floor heating instead of conventional radiator resulted in a saving of 17% and 22% in heat pump's electricity consumption, respectively. This would reduce the CO2 emission from the building's heating system by 21 % for the floor heating and by 18% for the ventilation radiator compared to the conventional radiator.

  • 32.
    Hesaraki, Arefeh
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Halilovic, Armin
    KTH, School of Technology and Health (STH), Basic Science and Biomedicine, Basic science.
    Holmberg, Sture
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Low-temperature Heat Emission Combined with Seasonal Thermal Storage and Heat Pump2015In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 119, p. 122-133Article in journal (Refereed)
    Abstract [en]

    We studied the application of a stratified seasonal hot water storage tank with a heat pump connected to medium-, low- and very-low-temperature space heat emissions for a single-family house in Stockholm, Sweden. Our aim was to investigate the influence of heat emission design temperature on the efficiency and design parameters of seasonal storage in terms of collector area, the ratio of storage volume to collector area (RVA), and the ratio of height to diameter of storage tank. For this purpose, we developed a mathematical model in MATLAB to predict hourly heat demand in the building, heat loss from the storage tank, solar collector heat production, and heat support by heat pump as a backup system when needed. In total, 108 cases were simulated with RVAs that ranged from 2 to 5 (m3 m−2), collector areas of 30, 40, and 50 (m2), height-to-diameter-of-storage-tank ratios of 1.0, 1.5, and 2.0 (m m1), and various heat emissions with design supply/return temperatures of 35/30 as very-low-, 45/35 as low-, and 55/45 (°C) as medium-temperature heat emission. In order to find the best combination based on heat emission, we considered the efficiency of the system in terms of the heat pump work considering coefficient of performance (COP) of the heat pump and solar fraction. Our results showed that, for all types of heat emission a storage-volume-to-collector area ratio of 5 m3 m2, with a collector area of 50 m2, and a height-to-diameter ratio of 1.0 m m1 were needed in order to provide the maximum efficiency. Results indicated that for very-low-temperature heat emission the heat pump work was less than half of that of the medium-temperature heat emission. This was due to 7% higher solar fraction and 14% higher COP of heat pump connected to very-low-temperature heat emission compared to medium-temperature heat emission.

  • 33.
    Hesaraki, Arefeh
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Holmberg, Sture
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    An investigation of energy efficient and sustainable heating systems for buildings: Combining photovoltaics with heat pump2013In: Sustainability in Energy and Buildings: Proceedings of the 4th International Conference in Sustainability in Energy and Buildings (SEB´12), Springer Berlin/Heidelberg, 2013, p. 189-197Conference paper (Refereed)
    Abstract [en]

    Renewable energy sources contribute considerable amounts of energy when natural phenomena are converted into useful forms of energy. Solar energy, i.e. renewable energy, is converted to electricity by photovoltaic systems (PV). This study was aimed at investigating the possibility of combining PV with Heat Pump (HP) (PV-HP system). HP uses direct electricity to produce heat. In order to increase the sustainability and efficiency of the system, the required electricity for the HP was supposed to be produced by solar energy via PV. For this purpose a newly-built semi-detached building equipped with exhaust air heat pump and low temperature-heating system was chosen in Stockholm, Sweden. The heat pump provides heat for Domestic Hot Water (DHW) consumption and space heating. Since selling the overproduction of PV to the grid is not yet an option in Sweden, the PV should be designed to avoid overproduction. During the summer, the HP uses electricity only to supply DHW. Hence, the PV should be designed to balance the production and consumption during the summer months. In this study two simulation programs were used: IDA Indoor Climate and Energy (ICE) as a building energy simulation tool to calculate the energy consumption of the building, and the simulation program WINSUN to estimate the output of the PV. Simulation showed that a 7.3 m2 PV area with 15 % efficiency produces nearly the whole electricity demand of the HP for DHW during summer time. As a result, the contribution of free solar energy in producing heat through 7.3 m2 fixed PV with 23o tilt is 17 % of the annual heat pump consumption. This energy supports 51 % of the total DHW demand.

  • 34.
    Hesaraki, Arefeh
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Holmberg, Sture
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Demand Controlled Ventilation in a Combined Ventilation and Radiator System2013In: Proceedings of International Conference CLIMA 13, 2013Conference paper (Other academic)
    Abstract [en]

    With growing concerns for efficient and sustainable energy treatment in buildings there is a need for balanced and intelligent ventilation solutions. This paper presents a strategy for demand controlled ventilation with ventilation radiators, a combined heating and ventilation system. The ventilation rate was decreased from normal requirements (per floor area) of 0.375 l·s-1·m-2 to 0.100 l·s-1·m-2 when the residence building was un-occupied. The energy saving potential due to decreased ventilation and fan power was analyzed by IDA Indoor Climate and Energy 4 (ICE) simulation program. The result showed that 16 % of the original energy consumption for space and ventilation heating could be saved by utilizing ventilation on demand.

  • 35.
    Hesaraki, Arefeh
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Holmberg, Sture
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Demand-controlled ventilation in new residential buildings: consequences on indoor air quality and energy savings2015In: Indoor + Built Environment, ISSN 1420-326X, E-ISSN 1423-0070, Vol. 24, no 2Article in journal (Refereed)
    Abstract [en]

    The consequences on indoor air quality (IAQ) and potential of energy savings when using a variable airvolume (VAV) ventilation system were studied in a newly built Swedish building. Computer simulationswith IDA Indoor Climate and Energy 4 (ICE) and analytical models were used to study the IAQ andenergy savings when switching the ventilation flow from 0.375 ls1m2 to 0.100 ls1m2 duringunoccupancy. To investigate whether decreasing the ventilation rate to 0.1 ls1m2 during unoccupancy,based on Swedish building regulations, BBR, is acceptable and how long the reduction can lastfor an acceptable IAQ, four strategies with different VAV durations were proposed. This study revealedthat decreasing the flow rate to 0.1 ls1m2 for more than 4 h in an unoccupied newly built buildingcreates unacceptable IAQ in terms of volatile organic compounds concentration. Hence, if the durationof unoccupancy in the building is more than 4 h, it is recommended to increase the ventilation rate from0.100 ls1m2 to 0.375 ls1m2 before the home is occupied. The study showed that when the investigatedbuilding was vacant for 10 h during weekdays, increasing the ventilation rate 2 h before occupantsarrive home (low ventilation rate for 8 h) creates acceptable IAQ conditions. In this system, theheating requirements for ventilation air and electricity consumption for the ventilation fan weredecreased by 20% and 30%, respectively.

  • 36.
    Hesaraki, Arefeh
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Holmberg, Sture
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Energy Performance Evaluation of New Residential Buildings with a Low-Temperature Heating System: Results from Site Measurements and Building Energy Simulations2012In: Proceedings of The Second International Conference on Building Energy and Environment, 2012Conference paper (Other academic)
    Abstract [en]

    The purpose of this study was to investigate the national energy requirements of a modern, newly built residential development including four semi-detached houses in Stockholm, Sweden. The apartments were equipped with heat pumps utilising exhaust heat, resulting in a hydronic heating system adapted to low supply temperature. Ventilation radiators as combined ventilation and heating systems were installed in the two upper floors. Efficient preheating of incoming ventilation air in the ventilation radiator was an expected advantage. Under-floor heating with traditional air supply above windows was used on the ground floor. Energy consumption was calculated by IDA ICE 4, a building energy simulation (BES) program. In addition site measurements were made for comparison and validation of simulation results. Total energy consumption was monitored in the indoor temperature controlled buildings during the heating season. Our results so far indicate that total energy requirements in the buildings can be met in a satisfactory manner.

  • 37.
    Hesaraki, Arefeh
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Holmberg, Sture
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Energy performance of low temperature heating systems in five new-built swedish dwellings: A case study using simulations and on-site measurements2013In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 64, p. 85-93Article in journal (Refereed)
    Abstract [en]

    In Europe, high energy consumption in built environments has raised the need for developing low energy heating systems both in new building and in retrofitting of existing buildings. This paper aims to contribute by presenting annual results of calculated and measured energy consumption in five new-built semi-detached dwellings in Stockholm, Sweden. All buildings were equipped with similar low temperature heating systems combining under-floor heating and ventilation radiators. Exhaust ventilation heat pumps supported the low temperature heating system. Buildings were modeled using the energy simulation tool IDA Indoor Climate and Energy (ICE) 4, and energy consumption of the heat pumps was measured. Results showed that calculated and measured results were generally in agreement for all five dwellings, and that the buildings not only met energy requirements of the Swedish building regulations but also provided good thermal comfort.

  • 38.
    Hesaraki, Arefeh
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Holmberg, Sture
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Haghighat, Fariborz
    Energy-Efficient and Sustainable Heating System for Buildings: Combining seasonal heat storage with heat pumps and low-temperature heating systems2014Conference paper (Refereed)
    Abstract [en]

    During gaps between high heating demand in winter and high heating production in summer, the application of seasonal thermal energy storage becomes important. However, heat loss from seasonal thermal energy storage has always been an issue. Therefore, in order to decrease heat loss and increase solar collector efficiency, low-temperature heat storage is recommended. Nevertheless, this temperature is not sufficient throughout the heating season, which means that a heat pump is recommended in order to use this low-grade source to produce a suitable temperature for the heating system. In addition, heat pumps have better efficiency when working with low-temperature heating systems. This study investigated the seasonal thermal storage in combination with heat pump and low-temperature heating systems, with the aim of finding a suitable size for thermal energy storage and collector area. The study showed that 300 m3 of storage volume and 55 m2 of collector area could cover 80 % of the total energy demand using solar energy.

  • 39.
    Hesaraki, Arefeh
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Holmberg, Sture
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Haghighat, Fariborz
    Seasonal thermal energy storage with heat pumps and low temperatures in building projects-A comparative review2015In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 43, p. 1199-1213Article, review/survey (Refereed)
    Abstract [en]

    Application of seasonal thermal energy storage with heat pumps for heating and cooling buildings has received much consideration in recent decades, as it can help to cover gaps between energy availability and demand, e.g. from summer to winter. This has the potential to reduce the large proportion of energy consumed by buildings, especially in colder climate countries. The problem with seasonal storage, however, is heat loss. This can be reduced by low-temperature storage but a heat pump is then recommended to adjust temperatures as needed by buildings in use. The aim of this paper was to compare different seasonal thermal energy storage methods using a heat pump in terms of coefficient of performance (COP) of heat pump and solar fraction, and further, to investigate the relationship between those factors and the size of the system, i.e. collector area and storage volume based on past building projects including residences, offices and schools.

  • 40.
    Hesaraki, Arefeh
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Myhren, Jonn Are
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Holmberg, Sture
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Influence of Different Ventilation Levels on Indoor Air Quality and Energy Saving: a Case Study of a Renovated Single-family HouseManuscript (preprint) (Other academic)
  • 41.
    Hesaraki, Arefeh
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Myhren, Jonn Are
    Holmberg, Sture
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Influence of different ventilation levels on indoor air quality and energy savings: A case study of a single-family house2015In: Sustainable cities and society, ISSN 2210-6707, Vol. 19, p. 165-172Article in journal (Refereed)
    Abstract [en]

    The influence of different ventilation levels on indoor air quality (IAQ) and energy savings were studied experimentally and analytically in a single-family house occupied by two adults and one infant, situated in Borlange, Sweden. The building studied had an exhaust ventilation system with a range of air flow rate settings. In order to find appropriate ventilation rates regarding CO2, relative humidity (RH) and temperature as indicators of IAQ, four ventilation levels were considered, as follows: (I) A very low ventilation rate of 0.10 L s(-1) m(-2); (II) A low ventilation rate of 0.20 L s(-1) m(-2); (III) A normal ventilation rate of 0.35 L s(-1) m(-2); (IV) A high ventilation rate of 0.70 L s(-1) m(-2). In all cases, the sensor was positioned in the exhaust duct exiting from habitable spaces. Measurements showed that, for case I, the CO2 concentration reached over 1300 ppm, which was higher than the commonly referenced threshold for ventilation control, i.e. 1000 ppm, showing unacceptable IAQQ. In case II, the CO2 level was always below 950 ppm, indicating that 0.20 L s(-1) m(-2) is a sufficient ventilation rate for the reference building. The case III showed that the ventilation rate of 0.35 L s(-1) m(-2) caused a maximum CO2 level of 725 ppm; showing the level recommended by Swedish regulations was high with respect to CO2 level. In addition, measurements showed that the RH and temperature were within acceptable ranges in all cases. An energy savings calculation showed that, in case II, the comparative savings of the combined energy requirement for ventilation fan and ventilation heating were 43% compared with case.

  • 42.
    Hesaraki, Arefeh
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Myhren, Jonn Are
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Holmberg, Sture
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Multi-zone Demand-controlled Ventilation in Residential Buildings: An experimental case study2014Conference paper (Refereed)
    Abstract [en]

    Numerous studies have investigated the application of multi-zone demand-controlled ventilation for office buildings. However, although Swedish regulations allow ventilation rates in residential buildings to be decreased by 70 % during non-occupancy, this system is not very common in the sector. The main focus of the present study was to experimentally investigate the indoor air quality and energy consumption when using multi-zone demand-controlled ventilation in a residential building. The building studied was located in Borlänge, Sweden. This building was recently renovated with better windows with low U values, together with internally-added insulation materials. The building had natural ventilation, which decreased significantly after retrofitting and resulted in poor indoor air quality. Therefore, a controllable mechanical ventilation system was installed. The ventilation rate was controlled according to the demand in each zone of the building by CO2 concentration as an indicator of indoor air quality in habitable spaces and relative humidity and VOC level in the toilet and bathroom. The study showed that multi-zone demand-controlled ventilation significantly reduced the CO2 concentration leading to improvement in indoor air quality. However, building with demand-controlled ventilation consumed more energy than natural ventilation as it increases the ventilation loss by forcing more air into the building. Nevertheless, in the demand-controlled ventilation system, the energy consumption for the ventilation fan and ventilation loss was almost half of the constant high rate ventilation flow.

  • 43.
    Hesaraki, Arefeh
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Ploskic, Adnan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Holmberg, Sture
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Integrating Low-temperature Heating Systems into Energy Efficient Buildings2015In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 78, p. 3043-3048Article in journal (Refereed)
    Abstract [en]

    Energy requirements for space heating and domestic hot water supplies in the Swedish building sector are responsible for almost 60 % of the total energy used. To decrease this enormous figure, energy saving measures are required, as well as opportunities to use low-temperature heating systems for increase sustainability. The present paper studies low-temperature heating systems, including heat production units (district heating or heat pumps) and heat emitting units in the room. The aim was to find an answer to the question of whether or not low-temperature heating systems are energy efficient and sustainable compared with conventional heating systems. To answer this question, we considered different efficiency aspects related to energy and exergy. The analysis showed that low-temperature heating systems are more energy efficient and environmentally friendly than conventional heating systems. This was attributed to heat pumps and district heating systems with lower temperature heat emitters using a greater share of renewable resources and less auxiliary fuels. This report discusses the pros and cons of different types of low-temperature heat emitters.

  • 44.
    Holmberg, Sture
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Alenius, Sven
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Chen, Shih-Ying
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Drug-resistant bacteria in hospital wards - the role of ventilation2009In: 9th International Conference and Exhibition - Healthy Buildings 2009, HB 2009, 2009, p. 596-Conference paper (Refereed)
    Abstract [en]

    To limit the airborne spread of infectious agents (antibiotic-resistant bacteria) in hospital wards is an increasing world-wide concern. A multi-disciplinary Swedish research team is together with industry focusing on this problem. New knowledge is sought on how building ventilation services should be designed to minimize the risk of airborne infectious agents. In the literature there is strong and sufficient evidence to demonstrate the association between ventilation, air movements in buildings and the transmission/spread of diseases. There is, however, insufficient data to specify and quantify the minimum ventilation requirements in relation to the spread of infectious diseases via the airborne route. The latest developments in the advanced numerical simulation (CFD) methods offer new possibilities to follow the routes of airborne contaminants. Many ventilation parameters, including air flow rates, thermal and pressure conditions as well as the behavior of persons in the room are analyzed. The influence of both local air supply and local air exhaust has been analyzed and very promising results from this part of the work are presented. A bacterium spread from a patient confined to his bed was limited and for certain conditions almost eliminated. Ventilation and spatial parameter combinations to limit and prevent the spread of contaminants are mapped for different hospital wards. The risk of airborne transmission is modeled and discussed. Implementation in practice is sought via close collaboration with industry.

  • 45.
    Holmberg, Sture
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Myhren, Jonn Are
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Ploskic, Adnan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Low-temperature heat emission with integrated ventilation air supply2010In: Proceedings of International Conference Clima 2010, 2010Conference paper (Refereed)
  • 46.
    Horttana, J
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Energideklarationen - Hur ändra värmesystemet ?2009Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • 47.
    Hugo, M
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Johansson, E
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Besparingsåtgärder för värmepumpar i byggnader2006Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • 48.
    Jin, Quan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Duanmu, L.
    Thermal sensation and skin temperature during step-changes in non-uniform indoor environment2014In: Indoor Air 2014 - 13th International Conference on Indoor Air Quality and Climate, 2014, p. 175-182Conference paper (Refereed)
    Abstract [en]

    To examine thermal sensation in non-uniform environment, this paper studied overall thermal sensation and skin temperature during step-change between an ambient and the workstation where local ventilation device was installed to supply air motion around the head. 23 human subject tests were conducted in summer for cooling in a controlled environment chamber. Thermal sensations and skin temperatures were collected and analysed by statistical tests. Thermal sensation's changing trends of hysteresis and overshooting were found respectively after stepping into the ambient and the workstation. Face skin temperature changed closely with thermal sensation, while it had no overshooting phenomenon as thermal sensation did. The minimum change of face skin temperature required for a just noticeable difference on thermal sensation was calculated. In conclusion, thermal sensation's changing rules are comfort positive for non-uniform thermal environment. Face skin temperature well explained thermal sensation's changing characters during step-changes with different local cooling methods.

  • 49.
    Joelsson, A
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Bengtsson, M
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Designpaneler för ökad värmeöverföring från radiatorer i lågtemperatursytem2006Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • 50.
    Jonsson, P
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Ahlstrand, J
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Forcerad konvektion i lågtemperatursystem2005Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
123 1 - 50 of 138
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