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  • 1.
    Andersson, Staffan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Utvärdering av energieffektiva armaturer2015Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Rapporten redovisar en genomförd uppföljning av den erhållna minskningen av varm- respektive kallvattenanvändningen genom installation av energieffektiva armaturer. Utvärderingen baseras på 23 månaders mätningar av den individuella vattenanvändningen i sjuttiosju lägenheter (21 test-samt 56 referenslägenheter). Testlägenheterna utrustades först med en tidigare generations vattenarmaturer, FM Mattsson serie 9000, vilka senare ersattes med den senaste generationens armaturer FM Mattson serie 9000E. I fem av dessa lägenheter har dessutom komplementerande mätningar gjorts vid de olika tappställena, WC undantagen. Användningen av varm- och kallvattenanvändningen i varje lägenhet har loggats med en tidsupplösning om 10 minuter. För att undvika påverkan av boendes frånvaro från lägenheterna har uppföljningen baserats på den genomsnittliga dygnsanvändningen av vatten för de tider de boende har nyttjat lägenheten. Lägenheter där byte av hyresgäster har skett under utvärderingsperioden har lämnats utanför utvärderingen. De erhållna resultaten visar på en besparing om cirka 30% avseende varmvattenanvändningen samt 15% avseende kallvatten jämfört med referensgruppen. Den erhållna uppskattningen är också konsistent med en teoretisk uppskattning av besparingen baserad på den mätta förändringen av kvoten mellan varmvatten- och kallvattenanvändningen i testlägenheterna.

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  • 2.
    Andersson, Staffan
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Olofsson, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Östin, Ronny
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Predictions of energy demand in buildings using neural network techniques on performance data1996Ingår i: Proceedings of the 4th fourth symposium on building physics in the nordic countries, 1996, s. 51-58Konferensbidrag (Refereegranskat)
  • 3.
    Andersson, Staffan
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Sjögren, Jan-Ulric
    Östin, Ronny
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Olofsson, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Building performance based on measured data2011Ingår i: World Renewable Energy Congress – Sweden, 8–13 May, 2011, Linköping, Sweden: Energy End-Use Efficiency Issues / [ed] Moshfegh, Bahram, Linköping: Linköping University Electronic Press , 2011, s. 899-906Konferensbidrag (Refereegranskat)
    Abstract [en]

    With increasing liability for builders, the need for evaluation methods that focuses on the building’s performance and thus excludes the impact from residents’ behavior increases. This is not only of interest for new buildings but also when retrofitting existing buildings in order to reduce energy end-use.

    The investigation in this paper is based on extensive measurements on two fairly representative type of buildings, a single family building in Ekerö, Stockholm built 2000 and two apartment buildings in Umeå (1964) in order to extract key energy performance parameters such as the building’s heat loss coefficient, heat transfer via the ground and heat gained from the sun and used electricity.

    With access to pre-processed daily data from a 2-month periods, located close to the winter solstice, a robust estimate of the heat loss coefficient was obtained based on a regression analysis. For the single family building the variation was within 1% and for the two heavier apartment buildings an average variation of 2%, with a maximum of 4%, between different analyzed periods close to the winter solstice.

    The gained heating from the used electricity in terms of a gain factor could not be unambiguously extracted and therefore could only a range for the heat transfer via ground be estimated. The estimated range for the transfer via ground for the two apartment buildings were in very good agreement with those calculated according to EN ISO 13 370 and corresponded to almost 10% of the heating demand at the design temperature. For the single family building with an insulated slab and parts of the walls below ground level, the calculations gave slightly higher transfer than what was obtained from the regression analysis. For the estimated gained solar radiation no comparison has been possible to make, but the estimated gain exhibited an expected correlation with the global solar radiation data that was available for the two apartment buildings.

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  • 4.
    Andersson, Staffan
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Sjögren, Jan-Ulric
    Östin, Ronny
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Olofsson, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Prestanda- och betendeuppföljning av byggnaders energianvändning: etapp12010Rapport (Övrigt vetenskapligt)
  • 5.
    Lindbergh, Lars
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Företagsekonomi.
    Olofsson, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Vesterberg, Jimmy
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Andersson, Staffan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Wilson, Timothy
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Företagsekonomi.
    Reflections on sustainable Ålidhem: a case study in Swedish municipal public housing refurbishment2018Ingår i: Property Management, ISSN 0263-7472, E-ISSN 1758-731X, Vol. 36, nr 2, s. 203-220Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Purpose: This work is initiated under the premise that reliable evaluation methods are necessary to ensure investments in energy conservation, and the purpose of this paper is to contribute to that literature. It describes some pilot changes and their impact in an actual field study oriented toward upgrading municipal public housing (MPH) units.

    Design/methodology/approach: The research for this paper was connected to an MPH refurbishment project situated in northern Sweden. The overall energy efficiency goal within the project was a 40-50 percent reduction in the supplied energy for central electricity, domestic hot water and space heating. In order to evaluate if these goals were feasible, a measurement system was installed in a pilot building and in a neighboring building used as a reference. The evaluation was conducted by comparing the post-retrofit performance of the pilot building with the performance of the reference building when it was kept in its initial state (a comparison possible because both buildings had initial similarities).

    Findings: Impacts could be quantified insofar as a reference (control) building in the same environment was sustained for comparison purposes. A 43 percent improvement was observed in energy utilization in the pilot building compared to its reference companion (99.8 vs 174.5 kWh/m2 per year). When the approach described herein was applied to new construction, the present goal of 65 kWh/m2 was approached as measured by Swedish standards.

    Practical implications: Results should be of interest to academics in the housing field, professionals involved in refurbishment and residents themselves, renting MPH flats.

    Originality/value: This study is unique in the following ways: first, it really was a field experiment with a control, thus it did not have any exogenous interference in interpreting results. To the best of our knowledge, this is the first study of its kind. The second interesting characteristic was that results were subsequently used in the refurbishment of other buildings in the complex and in the construction of others. The major value of the paper may be associated with its timing. It comes at a time when the Kyoto agreement has raised concerns about sustainability, but also at a time when many buildings are facing a need for refurbishment.

  • 6.
    Lundin, Mikael
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Andersson, Staffan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Östin, Ronny
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Development and validation of a method aimed at estimating building performance parameters2004Ingår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 36, nr 9, s. 905-914Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents a method for estimating the total heat loss coefficient, the total heat capacity and the gain factor based on measured data for the internal-external temperature difference, the domestic load and the supplied heat. Knowledge of these performance parameters is essential for a reliable energy demand forecast, close guidance and the accurate analysis of efficiency actions in buildings. The method was validated on measurements from a test cell. The values obtained for the performance parameters were in good agreement with a lumped capacitance analysis of the heating and cooling of the test cell. The deviation in the total heat loss coefficient, expressed in terms of the root mean square error, was between 2.5 and 9.4%. The values obtained for the total heat capacity were on average 9.8% higher than the reference value and for the gain factor the average deviation was 12.5%. The method shows promising signs of becoming a robust and accurate tool for extracting both the magnitude and the variation of the performance parameters, based on easily accessible data.

  • 7.
    Lundin, Mikael
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Andersson, Staffan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Östin, Ronny
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Further validation of a method aimed to estimate building performance parameters2005Ingår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 37, nr 8, s. 867-871Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A further validation of an earlier developed neural network method for estimating the total heat loss coefficient (K-tot), the total heat capacity (C-tot) and the gain factor (alpha) based on measured diumal data of internal-external temperature difference, supplied heat for heating and "free heat" is presented. The validation was performed in laboratory scale, using a test cell, for three different cases of ventilation, without (constant)-, natural-, and forced ventilation. Earlier measurements from a building was also used in order to simulate a realistic energy use pattern and a rather stochastic behavior of alpha, which also was transformed to represent existing and future buildings in terms of the composition of their energy use. For all three types of ventilation and different types of buildings, the method was capable of estimating the three different performance parameters and their different dependencies. For K-tot, the RMSE was between 3 and 20% and for alpha, the deviation was between 9 and 19%.

  • 8.
    Nydahl, Helena
    et al.
    Umeå universitet.
    Andersson, Staffan
    Umeå universitet.
    Åstrand, Anders P.
    Umeå universitet.
    Olofsson, Thomas
    Umeå universitet.
    Building Refurbishment from a Life Cycle Perspective - An Environmental Return on Investment Approach2018Ingår i: Cold Climate HVAC 2018: Sustainable Buildings in Cold Climates, Springer, 2018, s. 253-263Konferensbidrag (Refereegranskat)
    Abstract [en]

    This study applies an environmental return on investment approach to evaluate building refurbishment from a life cycle perspective. The used methodology focuses on the changes introduced by refurbishment, i.e. added embodied environmental impact and changed operational environmental impact, from a life cycle perspective with the technical service life of the refurbishment measure as a time limit. The methodology is applied to a case study in Umeå, located 455 km south of the Arctic Circle, with a unique set of data on reduction in operational energy. The result show the environmental impact, energy (Joule) and GWP (CO2-eq), in terms of environmental return on investment of the case study refurbishment measures. The case study shows that the methodology is a useable approach to compare refurbishment measures from a life cycle perspective. It is possible to use the methodology as a tool at an early stage in planning of sustainable building refurbishment from a life cycle perspective. For a widespread use of a tool based on an environmental return on investment approach, further research on guidelines for sustainable environmental return on investment values is required.

  • 9.
    Nydahl, Helena
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Andersson, Staffan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Åstrand, Anders P.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Centrum för medicinsk teknik och fysik (CMTF).
    Olofsson, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Environmental Performance Measures to Assess Building Refurbishment from a Life Cycle Perspective2019Ingår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 12, nr 2, artikel-id 299Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Energy efficiency investments in existing buildings are an effective way of reducing the environmental impact of the building stock. Even though policies in the European Union and elsewhere promote a unilateral focus on operational energy reduction, scientific studies highlight the importance of applying a life cycle perspective to energy refurbishment. However, life cycle assessment is often perceived as being complicated and the results difficult to interpret by the construction sector. There is also a lack of guidelines regarding the sustainable ratio between the embodied and accumulated operational impact. The scope of this study is to introduce a life cycle assessment method for building refurbishment that utilizes familiar economic performance tools, namely return on investment and annual yield. The aim is to use the introduced method to analyze a case building with a sustainability profile. The building was refurbished in order to reduce its operational energy use. The introduced method is compatible with a theory of minimum sustainable environmental performance that may be developed through backcasting from defined energy and GHG emissions objectives. The proposed approach will hopefully allow development of sustainable refurbishment objectives that can support the choice of refurbishment investments.

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  • 10.
    Nydahl, Helena
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Andersson, Staffan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Åstrand, Anders P.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Olofsson, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Including future climate induced cost when assessing building refurbishment performance2019Ingår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 203, artikel-id 109428Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Improving energy efficiency in the existing buildings stock is essential to limit climate change and the economic assessment of measures are traditionally only based on the reduction of energy costs: However, future financial benefits of limiting climate change are rarely included in the evaluation of refurbishment investments. Although, the costs associated with global warming are expected to be extensive. This study introduces a method for the financial evaluation of energy efficiency investments that merge the reduction of life cycle energy costs with the reduction of future climate induced costs. A case study is used to exemplify the method. The case study shows that when reduced future costs due to mitigated life cycle greenhouse gas emissions are included in the analysis, the ranking between different measures can change and traditionally non-profitable measures may become financially sound investments. The introduced Economy+ indicator is shown to be an accessible performance measure to assess building refurbishment and may also be used in the design stage of new construction. (C) 2019 The Authors. Published by Elsevier B.V.

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  • 11.
    Olofsson, Thomas
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Andersson, Staffan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Analysis of the interaction between heating and domestic load in an occupied single family buildning1999Ingår i: Proceedings of the fifth symposium of building physics in the nordic countries / [ed] C.E. Hagentoft, P.I. Sandberg, 1999, s. 473-480Konferensbidrag (Refereegranskat)
  • 12.
    Olofsson, Thomas
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Andersson, Staffan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Long term energy demand predictions for buildings based on short-term measured data2001Ingår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 33, nr 2, s. 85-91Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In order to obtain long-term predictions based on short-term data, a neural network model was developed. The model parameters are indoor and outdoor temperature difference and energy for heating and internal use. For purposes of training the neural network model a method for extending the measured data to represent an annual variation is proposed. The method has been applied on six single-family buildings.

    Based on access to data from 2 to 5 weeks, the deviation between predicted and measured diurnal energy demand on an annual basis was about 4% with a correlation of 90–95%, when access to the indoor and outdoor temperature difference was assumed. For models based on access to data from the warmest periods with a very small heating demand, the deviation was about 2–4 times larger.

  • 13.
    Olofsson, Thomas
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Andersson, Staffan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Overall heat loss coefficient and domestic energy gain factor for single family buildings2002Ingår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 37, nr 11, s. 1019-1026Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this work we introduce a method for estimating the variation of the overall heat loss coe"cient and the domestic energy gain factor. Based on a neural network model, these parameters were extracted from analyzing the model by indirect methods. The used model parameters were: the supplied heating demand, the domestic electrical demand and the indoor–outdoor temperature di5erence. A feed-forward back propagation neural network was used as modeling tool. The proposed method has been found accurate, based on an analysis of arti6cially generated data. Additionally, measured data of inhabited single family buildings were examined and the model was found to generate reliable results, in parity with results obtained by comparable methods and estimations.

  • 14.
    Olofsson, Thomas
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Andersson, Staffan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Utvärdering av Energiprestanda med byggnadens värmeförlustfaktor2008Ingår i: Bygg och Teknik, nr 5, s. 47-50Artikel, forskningsöversikt (Övrigt vetenskapligt)
  • 15.
    Olofsson, Thomas
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Andersson, Staffan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Sjögren, Jan-ulric
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Building energy parameter investigations based on multivariate analysis2009Ingår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 41, s. 71-80Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    System identification can be used for evaluations of how measured energy use is influenced by theoperation, design and equipment of buildings and their users. However, it can be difficult to accessappropriate data for modelling purposes due to a small number of buildings, parameters not distributednormally, lumped information, etc. In this work, data of a subset of 112 comparable multifamily buildingslocated in the Stockholm area were derived from a larger Swedish building energy consumption survey.In that database, the accessible data are monthly consumption data together with a large number ofbuilding-specific classification parameters, e.g. building code, age of control system, type of owner,maintenance organization, area to let, etc.A multivariate PLS method (partial least squares to latent structures) was used to model differentenergy performance measures, such as the use of energy for heating, electricity used to operate thebuilding technical system, the building total heat loss coefficient and the use of domestic cold water. ThePLS model was investigated for both the total annual use and the annual use normalized to the availablefloor area. For most measures of performance, only qualitative estimates of the impact of differentclassification parameters could be drawn due to the goodness value of the model. However, for some ofthe investigated parameters, quantitative estimates could also be drawn. The obtained results are, inmost cases, in good agreement with what might be expected.To enable benchmarking of different energy use measures, the area to let is commonly used as anormalizer by real estatemanagers in Sweden. In this study, we find strong indications that the area to letis not suitable for this purpose.

  • 16.
    Olofsson, Thomas
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Andersson, Staffan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Sjögren, Jan-Ulric
    Multivariate Methods for Evaluating Building Energy Efficiency2004Ingår i: Proceedings of the 2004 ACEEE Summer Study of Energy Efficiency in Buildings, 2004, s. 265-274Konferensbidrag (Refereegranskat)
    Abstract [en]

    For an owner or operator of a building, benchmarking can be a useful guide for finding outhow energy efficient the building is and identifying what to improve. For successfulevaluation of the building energy efficiency, the categorization as well as the parameteridentification has decisive importance. That selection can be based on mathematical modelingsuch as linear regression accompanied with more or less user expert knowledge. Theselection, however, is not a simple task since analyses based on statistical data are sensitive tocorrelations between different measured parameters. For improving that analysis multivariatemethods such as Principal Component Analysis (PCA) can be a valuable support.We demonstrate here how PCA can be a useful tool for investigating aggregated statisticaldatasets. The investigation illustrates how a set of building performance parameters exhibitsdifferent relations depending on how the categorization is made, which is relevant to considerwhen benchmarking. The study is based on a national Swedish database of aggregated energyuse and building performance statistics.

  • 17.
    Olofsson, Thomas
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Andersson, Staffan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Östin, Ronny
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    A method for predicting the annual building heating demand based on limmited performance data1998Ingår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 28, nr 1, s. 101-108Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, we present an investigation of the possibility to use a neural network combined with a quasi-physical description in order to predict the annual supplied space heating demand (P) for a number of small single family buildings located in the North of Sweden. As a quasi-physical description for P, we used measured diurnal performance data from a similar building or simulated data from a steady state energy simulation software. We show that the required supplied space heating demand may be predicted with an average accuracy of 5%. The predictions were based on access to measured diurnal data of indoor and outdoor temperatures and the supplied heating demand from a limited time period, ranging from 10 to 35 days. The prediction accuracy was found to be almost independent of what time of the year the measurements were obtained from, except for periods when the supplied heating demand was very small. For models based on measurements from May and fo some buildings from April and September, the prediction was less accurate.

  • 18.
    Olofsson, Thomas
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Andersson, Staffan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Östin, Ronny
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Energy load predictions for buildings based on a total demand perspective1998Ingår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 28, nr 1, s. 109-116Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The outline of this work was to develop models for single family buildings, based on a total energy demand perspective, i.e., building-climate-inhabitants. The building-climate part was included by using a commercial dynamic energy simulation software. Whereas the influence from the inhabitants was implemented in terms of a predicted load for domestic equipment and hot water preparation, based on a reference building. The estimations were processed with neural network techniques. All models were based on access to measured diurnal data from a limited time period, ranging from 10 to 35 days. The annual energy predictions were found to be improved, compared to models based on only a building-climate perspective, when the domestic load was included. For periods with a small heating demand, i.e., May-September, the average accuracy was 7% and 4% for the heating and total energy load, respectively, whereas for the rest of the year the accuracy was on average 3% for both heating and total energy load.

  • 19.
    Olofsson, Thomas
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Andersson, Staffan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Östin, Ronny
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Using CO2 concentrations to predict energy consumption in homes1998Ingår i: Proceedings of the 1998 ACEEE Summer study of energy efficiency in buildings, 1998, s. 211-222Konferensbidrag (Refereegranskat)
  • 20.
    Olofsson, Thomas
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Sjögren, Jan-Ulric
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Andersson, Staffan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Energy Performance for Buildings Evaluated with Multivariate Analysis2005Ingår i: Proceedings of the of the Ninth IBPSA Conference and Exhibition, Building Simulation 2005, 2005, s. 891-898Konferensbidrag (Refereegranskat)
    Abstract [en]

    Numerous problems can occur for an investigatorof larger datasets, e.g. how to handledimensionality, many variables and fewobservations, few variables and many observations,correlations, missing data, noise and to extractinformation from all data simultaneously.Multivariate analysis (MVA) is an establishedmethod for dealing with such problems.In this work, we introduce a methodology based onMVA, which was developed to model the buildingenergy performance from the perspective of theproperty holder. Data from a Swedish database of500 buildings, which recently has been compiledand is under expansion, was used for theinvestigation. The available data consists ofbuilding specific information and consumptiondata, monitored on a monthly basis, reported by theproperty holder. Electrical consumption for lightingand appliances is paid by the tenants in Sweden,and is thus lacking in the database. This means thatthe data base just include the part of the total energyuse that is paid by the property holder. With theoverall goal to assess the energy use paid by theproperty holders, a methodology is suggested forestimating the electrical energy paid by the tenants.At this early stage of our work, we found that theused methodology gives a fairly robust model andthat the interpretation of the model is believed to beaccurate in terms of comparing the energy usebetween different buildings.

  • 21.
    Puttige, Anjan Rao
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Andersson, Staffan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Östin, Ronny
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Olofsson, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Method to estimate the ground loads for missing periods in a monitored GSHP2019Ingår i: EUROPEAN GEOTHERMAL CONGRESS 2019: THE HAGUE, 11-14 JUNE 2019, 2019Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Monitoring a ground source heat pump can provide important insights into its working, but to study the behaviour of the borehole heat exchanger (BHE) we require monitored data for the whole period of operation. In practice, the monitored data often has periods of missing data. We propose a method to estimate the load during the periods of missing data based on the fluid temperature after that period. The method determined the missing load with negligible error, for the case of a BHE that behaves exactly like the model describing it. A sensitivity analysis showed that the estimated load is highly sensitive to errors in measured load and fluid temperature. The method was applied to a real monitored BHE, the magnitude of estimated loads were unreasonably high, but the overall deviation between the measured and simulated values of fluid temperature decreased. Therefore, the high magnitude of missing load compensates for the lack of agreement between the model and the measured data.

  • 22.
    Puttige, Anjan Rao
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Andersson, Staffan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Östin, Ronny
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Olofsson, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Method to estimate the ground loads for missing periods in a monitored GSHP2019Ingår i: European Geothermal Congress 2019, 2019Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Monitoring a ground source heat pump can provide important insights into its working, but to study the behaviour of the borehole heat exchanger (BHE) we require monitored data for the whole period of operation. In practice, the monitored data often has periods of missing data. We propose a method to estimate the load during the periods of missing data based on the fluid temperature after that period. The method determined the missing load with negligible error, for the case of a BHE that behaves exactly like the model describing it. A sensitivity analysis showed that the estimated load is highly sensitive to errors in measured load and fluid temperature. The method was applied to a real monitored BHE, the magnitude of estimated loads were unreasonably high, but the overall deviation between the measured and simulated values of fluid temperature decreased. Therefore, the high magnitude of missing load compensates for the lack of agreement between the model and the measured data.

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  • 23.
    Sjögren, Jan-Ulric
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Andersson, Staffan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Olofsson, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    An approach to evaluate the energy performance of buildings based on incomplete monthly data2007Ingår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 39, nr 8, s. 945-953Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The energy performance of buildings has become increasingly important in the general strive to reduce the overall energy use, which ismanifested in the Energy Performance of Buildings Directive launched by the European Union. An important first step is of course to identify andaddress buildings that have an energy saving potential. In order to achieve this, robust methods for evaluation as well as reliable energy key figuresare needed.For a large majority of multifamily buildings in Sweden the available data of the energy use originates from the property holder. Unfortunately,the data is often limited to the energy that the property holder is responsible for. Thus, information from the tenants about their household electricityuse, indoor temperatures, number of residents, etc., is missing.In this paper an evaluation was conducted on monthly consumption data registered by the property holders for over 100 multifamily buildings/real estates in Sweden. The used approach, based on the energy signature method, was developed for evaluating the energy performance ofmultifamily buildings in terms of the overall heat loss coefficient, Ktot. To compensate for the missing data, different assumed consumption profileshave been used.The results shows that although the obtained value of Ktot for an individual building is rather sensitive to the assumed consumption profiles ofhousehold electricity, the sensitivity is reduced if the evaluation is made in relative and not absolute terms. Thus, the use of consumption profilescould be a successful way to circumvent the present lack of a detailed knowledge of a buildings total energy use. In addition, an evaluation inrelative terms instead of absolute values is also more correct, since available data in almost all cases does not support the determination of the truevalue of Ktot. The use of an average consumption profile instead of a detailed knowledge is of course not desirable, but for fairly large buildings suchan approach could be successful.

  • 24.
    Sjögren, Jan-Ulric
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Andersson, Staffan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Olofsson, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Sensitivity of the total heat loss coefficient determined by the energy signature approach to different time periods and gained energy2009Ingår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 41, nr 7, s. 801-808Artikel i tidskrift (Refereegranskat)
    Abstract [en]

     

    In order to identify buildings that have energy saving potential there is a need for further development of robust methods for evaluation of energy performance as well as reliable key energy indicators. To be able to evaluate a large database of buildings, the evaluation has to be founded on available data, since an in-depth analysis of each building would require large measurement efforts in terms of both parameters and time. In practice, data are usually available for consumed energy, water, and so on, namely consumption that the tenants or property holder has to pay for. In order to evaluate the energy saving potential and energy management, interesting key energy indicators are the total heat loss coefficient Ktot (W/K), the indoor temperature (Ti), and the utilisation of the available heat (solar radiation and electricity primarily used for purposes other than heating). The total heat loss coefficient, Ktot, is a measure of the heat lost through the building's envelope, whereas Ti and the gained energy reflect the user's behaviour and efficiency of the control system.

    In this study, a linear regression approach (energy signature) has been used to analyse data for 2003–2006 for nine fairly new multifamily buildings located in the Stockholm area, Sweden. The buildings are heated by district heating and the electricity used is for household equipment and the buildings’ technical systems. The data consist of monthly energy used for heating and outdoor temperature together with annual water use, and for some buildings data for household electricity are also available. For domestic hot water and electricity, monthly distributions have been assumed based on data from previous studies and energy companies. The impact on Ktot and Ti of the time period and assumed values for the utilised energy are investigated.

    The results show that the obtained value of Ktot is rather insensitive to the time period and utilised energy if the analysis is limited to October–March, the period of the year when the solar radiation in Sweden yields a minor contribution to heating. The results for the total heat loss coefficient were also compared to the calculations performed in the design stage; it was found that Ktot was on average 20% larger and that the contribution to heating from solar radiation was substantially lower than predicted. For the indoor temperature, however, the utilised energy had a large impact.

    With access to an estimate of Ktot and Ti, an improved evaluation of the energy performance may be achieved in the Swedish real estate market. At present the measure commonly used, despite the fact that monthly data is available, is the annual use of energy for space heating per square metre of area to let.

  • 25.
    Vesterberg, Jimmy
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Andersson, Staffan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Achieved Energy and Climate Goals in Project Ålidhem: An Evaluation of a Refurbishment of 21 Swedish multifamily Buildings2017Ingår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 132, s. 51-56Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In Umeå, situated in the north part of Sweden, the largest refurbishment project undertaken by the public housing company in Umeå was completed in 2014. The project had ambitious goals to decrease the bought energy use for domestic hot water, building electricity and space heating, by 50 %. In order to achieve this, a variety of energy conservation measures were implemented in 21 multifamily buildings during the four-year project. This paper describes the used evaluation approaches and the achieved energy and climate goals. Finally, it offers some reflections that are hoped to be useful in similar projects. 

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  • 26.
    Vesterberg, Jimmy
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik. Industrial Doctoral School, Umeå University, Umeå, Sweden.
    Andersson, Staffan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Olofsson, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    A single-variate building energy signature approach for periods with substantial solar gain2016Ingår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 122, s. 185-191Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The use of regression analysis for the identification of building performance parameters based on measurements is often difficult due to collinearity between the outdoor temperature and the global solar radiation (S). This study proposes a method to overcome this issue. The proposed method is based on using the seasonal symmetry of S to pair data from time-periods equidistant from the winter solstice. In addition, a method to utilize synthetic data to fine-tune the paired-data approach is presented. To evaluate the paired-data approach, two years data from a multifamily building in Umeå was used to estimate the heat loss factor (air-to-air transmission including air leakage). The results were compared with results obtained when S was very low (S ≈ 0). It was found that, the fine-tuned paired-data approach resulted in a modest deviation in the heat loss factor with an average absolute deviation of 4.0%. The small deviation indicates that the paired-data approach can extend the use of single-variate regression models for accurate identification of heat loss factors to situations where the solar gain is substantial. The paired-data approach was also used to calibrate a commercial energy building simulation tool. 

  • 27.
    Vesterberg, Jimmy
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Andersson, Staffan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Olofsson, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Calibration of low-rise multifamily residential simulation models using regressed estimations of transmission losses2016Ingår i: Journal of Building Performance Simulation, Taylor & Francis, ISSN 1940-1493, E-ISSN 1940-1507, Vol. 9, nr 3, s. 304-315Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study, we evaluated a proposed calibration approach for whole-building energy simulation models. This approach was based on a regression analysis of measured data collected during a time period when the global solar radiation was the lowest. The proposed approach was compared with a more conventional calibration approach with different degrees of complexity, starting from design stage assumptions, through audits, and lastly by refining the model with detailed measurements and numerical calculations. The evaluation was performed using measured data from two multifamily buildings located in Umeå, Sweden, and the IDA ICE 4.61 simulation software. The best agreement between simulated and measured data was obtained with the proposed calibration approach. The monthly normalized mean bias error and the coefficient of variation was less than 5.0% and 6.0% respectively. For the conventional calibration approach, detailed measurements and time-consuming numerical calculations were required to reach similar results. 

  • 28.
    Vesterberg, Jimmy
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Andersson, Staffan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Olofsson, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Robustness of a regression approach, aimed for calibration of whole building energy simulation tools2014Ingår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 81, s. 430-434Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An approach, able to easily and effectively integrate field measured data in whole Building Energy Simulation (BES) models is crucial to increase simulation accuracy for existing buildings. In this paper the robustness of a linear regression method for extracting transmission losses above ground (including air leakage) and ground heat loss parameters are analyzed. The regression method is evaluated on two documented and monitored multifamily buildings with mechanical supply and exhaust ventilation systems, with and without heat recovery.   

    The obtained results are found to be robust, with variations less than 2% in the extracted estimates of transmission losses above ground (including air leakage) and with a high goodness of fit (R2>0.96) against measured data from two years. In addition, the estimations of the buildings ground heat loss were in good agreement with calculations in accordance with EN ISO 13370:2007. The high quality output from the used regression method serves as good prerequisites for the method to be used in conjunction with BES models to aid the analyst in a BES calibration process

  • 29.
    Vesterberg, Jimmy
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Andersson, Staffan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Olofsson, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    The influence from input data provided by the user on calculated energy savings2014Ingår i: 10th Nordic Symposium on Building Physics, Lund, Sweden,15-19 June, 2014, 2014, s. 1301-1308Konferensbidrag (Refereegranskat)
    Abstract [en]

    It is generally accepted that the most correct decisions are made when the used support system provides the most accurate description of the starting point as possible. That is, in this case, a detailed initial description of a building, planned to be refurbished and evaluated with the building energy simulation software IDA ICE (v 4.5).In order to assess this statement, we have used two different models to predict energy savings due to different planned energy conservation measures (ECMs):

     - A basic model based on inputs from currently available standards and as-built drawings.

     - A calibrated model based on an analysis of measurements from two months, together with measured air handling unit parameters, hourly electricity usage and indoor temperatures.

    The relative prediction differences between the models are investigated as well as compared with the actual outcome in a neighboring building where the analyzed ECMs have been implemented. The result indicates that a calibrated model should be used, in order to accurately determine the post-retrofit energy demand. However, if only investigation of ECMs which aims to decrease a buildings transmission loss is of interest, the findings suggest that BES calibration is of minor importance.

  • 30.
    Vesterberg, Jimmy
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Olofsson, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Andersson, Staffan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Evaluation of energy conservation measures in a multifamily building, using on site measurements2012Konferensbidrag (Refereegranskat)
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