Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE credits
The historic Morkarlby Nedre Skola from 1914 is to be converted into offices on the ground floor and residential units in the attic. This study evaluates if the proposed conversion meets the requirements of the Swedish building regulation (Boverketsbyggregler, BBR) for energy performance and daylighting, as well the SS-EN 15251 (2007) standard for thermal comfort. In cases when the requirements are not met, materials and methods compatible with the historic status of the building are both proposed, and their impact assessed.
As a part of this study, the history and status of the building was briefly researched. The original and remaining parts of the construction are established on the bases of the plans supplied by Structor AB and Mora Bygg and via a walkthrough.
Relevant literature is reviewed on historic building materials and retrofit techniques are also reviewed and presented.
The thermal and visual performance of the building is evaluated with building energy performance simulation software IDA Indoor Climate and Energy (IDA ICE). The results revealed that the building neither meets the energy performance requirements of the BBR nor the standard for thermal comfort. The BBR requirement for daylighting is met in allrooms, but one.
In order to improve the energy efficiency of the building, retrofit strategies are tested individually and in combination utilizing IDA ICE. The strategies can be divided into two categories: heating energy saving measures and passive cooling strategies. The former includes measures such as upgrading of the windows with triple glazing and of the building envelope with the addition of 12 cm wood fiber insulation, and improved thermal bridges and air tightness, as well as extra heat losses through domestic hot water, and replacement of radiators with low temperature floor heating. The second category includes addition of external shading that is regulated through solar radiation, and utilization of natural ventilation which is utilized if the operative temperature of the room reaches 26 °C. Mechanical cooling solutions are not tested in this study.
The study found that for meeting the needed energy efficiency and thermal comfort requirements, both the energy saving retrofits and passive cooling strategies are needed. It is, however, not necessary to replace the existing radiators with low temperature floorheating, as this measure has a higher energy demand than the radiators and similar thermal comfort level. Utilized by itself in the uninsulated base case, the floor heating system does not cover the heating load and lowers thermal comfort.
As a final step, exhaust ventilation was added to the attic bathrooms and modelled in as implified manner using IDA ICE, as there had previously not been a mechanical ventilation system in the building, only natural ventilation. Although this change leads toincreased energy demand, the building still remains within the recommended range ofenergy demand and thermal comfort by BBR and SS-EN, respectively.
2022.