Energibehov i flerbostadshus – Antagandemodeller för tappvarmvatten

Abstract

This postgraduate thesis examines various assumption models for energy usage for water heating used in Sweden. The models are compared with the measured energy use in a number of small apartment buildings. Norway and Finland currently use standard models for energy calculations during the production of new buildings but in Sweden the planners are free to select an appropriate model of their choice. This thesis paper examines whether there is a model that is better than the others or if there is a need for a completely new model. Eight basic models are examined with various assumptions which in total will be 15 different energy calculations for nine reference areas. Assumptions are based on for example the number of apartments, area and number of habitants. The reference apartments consist of buildings with four to six apartments, because of the small size of the houses assumption models for single-family houses are also tested. All reference areas consist of the same types of houses, the only differences is the size of the territories, geography and if they are housing associations or rented. The majority of homes are heated with district heating, two of the areas are heated by gas. They all use exhaust ventilation. The reference areas actual energy use for water heating is obtained by using three different methods. •The first method works with the assumption that 25 % of the total energy demand for heating consists of tap water heating. Energy losses from pipes between the central and the houses are deducted before the energy use for hot water is calculated.
•The second method is based on the assumption that all energy purchased during the summer months only go to tap water heating. After a correction for lower water flows during the summer, the energy use can be used as a basis for the whole years energy demand for hot water heating.
•The third method is based on the assumption that 40 % of the water volume used, is made up of hot water. By multiplying the volume with the energy use to heat it you get the energy demand. The second method is the only one that is specific to the reference areas and it shows an energy demand which is well above the normal user according to the other two statistical methods. This is believed to be due to both a high energy use in the apartments and that the statistics available today are outdated and need to be corrected to describe today's construction. The study shows that there are several assumption models that in a good way describe the energy demand during normal usage. The models however, underestimate the reference areas needs. Because of the high energy use, the statistics can not be used as a basis for a new model. There are some suspicions about why energy use is as high as it is. •It may be due to a higher housing density than is usual in block of flats.
•The reference areas limited size means that extreme users are seen very clearly in the statistics.
•It may be that there are large energy losses due to poor insulation of pipes between the heating central and the houses, or over-sizing of hot water circulation. •It has also been discussed wether the reference areas have an energy use during the summer beside the demand for hot water. The hot water circulation is running constant all year, it is unclear how this affects the energy demand during the summer.

• author: Vogel, Daniel and Mattsson, Mårten
• organization: Civil Engineering - Architecture (BSc)
• year: 2009
• type: M2 - Bachelor Degree
• subject: Technology and Engineering
• keywords: antagandemodell, beräkningsmodell, uppvärmning, varmvatten, energibehov, tappvatten, specifik energianvändning, flerbostadshus
• language: Swedish
• id: 1464472
• date added to LUP: 2009-08-19 00:00:00
• date last changed: 2018-10-18 10:06:44