Energy Variations in Apartment Buildings Due to Different Shape Factors and Relative Size of Common Areas

I. Danielski
Mid Sweden University, Östersund, Sweden

Ladda ner artikelhttp://dx.doi.org/10.3384/ecp110571000

Ingår i: World Renewable Energy Congress - Sweden; 8-13 May; 2011; Linköping; Sweden

Linköping Electronic Conference Proceedings 57:33, s. 1000-1007

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Publicerad: 2011-11-03

ISBN: 978-91-7393-070-3

ISSN: 1650-3686 (tryckt), 1650-3740 (online)


A multi-storey residential building includes different sub areas; for example: apartment areas and common areas (corridors; basements; attic etc.). Each sub area may have different specific final energy use. Areas with lower specific final energy use will have a relatively lower contribution to total final energy use of a building. Examples of areas with low specific final energy use are corridors; basement and attics. All these areas are included in the calculation of a building’s total final energy use. As a result; there is a risk that buildings designers may fulfill stricter end-use energy requirements simply by constructing buildings with larger areas containing a lower specific final energy use. In addition; the envelope area of the building may vary for a given floor area depending on the shape factor of the building. The heat losses of a building depend on the envelope area; the area that is in direct contact outdoor environment. Thus; buildings with a lower shape factor will have lower heat losses and hence a lower specific final energy use.

In this paper; we study the impact of those two factors on the specific final energy use of similar constructed apartment buildings in Stockholm. We consider 22 multi-storey residential buildings in ten locations that were built in accordance with the Stockholm program for environmental adapted buildings. They were chosen since they have different ratio of common area to total heated area and large variation in specific final energy use. Other characteristics such as energy systems; construction properties and population density were similar.

The analyses showed a high correlation between the shape factor of the buildings and their specific final energy use. An increased shape factor of a building by 0.1 increased the specific final energy use by 5.3 kWh/m2. The specific final energy use of the studied buildings could vary up to 30 kWh/m2 only because of the shape factor. Therefore it is recommended that the shape factor is considered in building codes for new buildings especially in cold climates. The energy simulations showed that the specific final energy use in the common areas was about 75% lower than in apartment areas. Hence; including larger common areas in the design of new apartment buildings reduce the specific final energy use significantly while the final energy use per resident will increase. This needs to be considered in energy requirements of buildings. Normalizing the final energy use by the apartment area should be considered as alternative method as it reduces variations in specific final energy use due to the relative size of common areas and increases the quality of using the SFEU for energy requirements.


Specific final energy use; Shape factor; Surface area to volume ratio; Energy variation


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