Energiförluster från vs-rör med intilliggande balkong : Parameterstudie i Comsol Multiphysics

Sammanfattning: Energy issues are today in high priority nationally and internationally as its impact on the environment and climate has become increasingly apparent. The real estate sector accounts for 34 % of Sweden's total energy consumption, where 70 % goes to heating apartment buildings. In order to create a more energy-efficient and climate-smart society, the EU Commission has set the goal of reducing greenhouse gas emissions by at least 55 % relative to levels from 1990. Furthermore, Sweden's Riksdag decided to reduce energy use in buildings by 50 % by 2050 relative to 1995 levels. In order to reach the goals, technical solutions that can reduce energy losses in buildings are required, among other things. Furthermore, there is an undesirable energy transport via cold bridges that occur in the building's climate shell. The study deals with the combination of cast-in vs-pipes with an adjacent balcony where linear thermal bridges occur.  The purpose of the study was to gain an increased understanding of the heat release from vs pipes with an adjacent balcony slab. The goal is to produce temperature profiles over the system, the vs pipes' heat output and how large a proportion the building can absorb, energy losses via the balcony plate and its climate impact in the form of carbon dioxide equivalents. Measures such as pipe insulation, use of egcobox and the laying of the pipes were investigated. Using the simulation tool Comsol Multiphysics, the study has modeled a transient system where temperature and wind data are retrieved for Karlstad. Four basic cases (egcobox+ with/without insulation, without egcobox + with/without insulation) were examined where the placement of the pipes was varied relative to the inside wall. Outdoor temperature and wind speed were obtained from SMHI on an hourly basis and the supply temperature of the pipes was varied with respect to the outdoor temperature where the return flow received a 10 ᵒC lower temperature. The results of the study showed that heat release for uninsulated and insulated pipes maintained an effect of 49 W/m and 11 W/m at 55 ᵒC where the difference was shown for the energy losses via the balcony plate. Going from uninsulated to insulated pipes could reduce energy losses via the balcony slab by up to 36%. By moving the pipes further into the room, the losses could be reduced by up to 57%. By increasing the laying of the pipes from 2 - 12 dm, the change in relation to other measures made a big impact. At a laying of approximately 3 m, the energy losses via the balcony plate were of a similar order of magnitude as if the pipes had not been in the joist. To further reduce losses, insulation or egcobox had to be used. The percentage of credited energy from the heat output of the pipes without egcobox was as low as 72 and 80% for insulated and non-insulated pipes, respectively, to approach 100% with increasing installation. With the help of measures such as insulation and egcobox, energy savings for a property can reach up to 5.4 percentage points, which increases the energy performance of apartments with a balcony. When using egcobox, the percentage landed at 84 and 88% for individual and non-insulated pipes, respectively, and then rose in step with increased installation. The climate impact had a linear relationship with energy savings, where an increased location could reduce a property's emissions by up to 1 ton of CO2-eq/year. By taking measures for the thermal bridge problem, the real estate sector can reduce its energy consumption and its climate impact for future projects