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- Olofsson, Thomas, 1968-, et al.
(författare)
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Energy Performance for Buildings Evaluated with Multivariate Analysis
- 2005
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Ingår i: Proceedings of the of the Ninth IBPSA Conference and Exhibition, Building Simulation 2005. ; , s. 891-898
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Konferensbidrag (refereegranskat)abstract
- 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.
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- Olofsson, Thomas, 1968-, et al.
(författare)
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Evaluations of energy performance for greenhouses based on multivariate analysis methodology
- 2006
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Ingår i: Proceedings of the IIIrd international symposium on models for plant growth, environmental control and farm management in protected cultivation (hortimodel 2006). - 9789066056091
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Konferensbidrag (refereegranskat)abstract
- Improved energy efficiency is very important in order to increase the profitability for the greenhouse industry in northern Europe. For example in the Närpes region in Finland the average energy consumption has been estimated to 525 kWh/m² and year. From the energy use perspective, an operated greenhouse is a very complex system. For evaluating the energy efficiency of a greenhouse and for identification of what to improve, an owner or operator will need guidance. It is however difficult to identify the most energy efficient concept from monitored performance and consumption data. Correlations between the investigated parameters can render the analysis very difficult. To facilitate and improve the analysis, multivariate statistical methods can be a valuable support. We introduce here a multivariate methodology for analysing monitored performance data from greenhouses, with the objective to illustrate ways of improving the energy efficiency. The methodology was applied to a data set from an operated greenhouse in Närpes in Finland. The results illustrate how improvements of transmission and ventilation influence the supplied space heat demand. The methodology was found to be easy to use and the accuracy of the evaluation on the available data set and the parameters appeared to be reasonable.
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- Sjögren, Jan-Ulric, et al.
(författare)
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Sensitivity of the total heat loss coefficient determined by the energy signature approach to different time periods and gained energy
- 2009
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Ingår i: Energy and Buildings. - : Elsevier. - 0378-7788 .- 1872-6178. ; 41:7, s. 801-808
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 7. |
- Westerlund, Kim, et al.
(författare)
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Energy Self-Sufficient Areas, a case study on the Vaasa Housing Fair
- 2008
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Ingår i: Proceedings of the Renewable Efficient Energy Nordic Conference, Vaasa Finland, July 9-11 20.
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Konferensbidrag (refereegranskat)abstract
- EU has targeted 20% renewable energy use by 2020 which has put great pressure on themember states to change energy production, and to use the energy in the most efficient way.New concepts are needed and state-of-the art solutions need to be much more wildly applied.One concept is energy self-sufficient initiatives. There are a number of such initiatives inEurope. One of the most recent ones has been established in Finland at Vaasa Housing Fairopening at July 11, 2008 demonstrating first time innovations and new developments andcombinations.Used technology at the Housing Fair in Vaasa, Finland 2008 is:• A fuel cell power plant running on biogas• Combination with a micro turbine also running on biogas• Utilising sea heat from piping submerged under the sea bottom with a novel technique• A low temperature district heat network directly providing low temperature heat andcooling to the houses• Passive building utilising state-of-the art solutions applicable for large productionvolumesThe housing fair consists of 42 single-family and small houses and 3 apartment houses. Inthis paper we will introduce the used energy supply technology. Based on official informationfrom a pilot study of design conditions conducted by the Geological Survey of Finland andthe technology suggested for the fair, the self sufficiency has been estimated. We concludethat there are reasonable conditions for self sufficiency in both heat and power for at least90% of the average year.Preliminary calculations show an energy self sufficiency of 120% for electricity and160% for heat. The calculations are using specific consumption values based on experienceas declared in this paper.The system is target for measurements, follow-up will be performed and the benefits and possibledrawbacks evaluated in further research.
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