Investigating the possibility of Jakobsgårdarna district in Borlänge, Sweden becoming a Positive Energy District (PED)

Sammanfattning: Climate change is a global phenomenon that strongly affect cities and urban areas. Due to the intensive industrial activities and global population growth leading to more fossil energy demands for the last century, the global warming effect appeared to have been significantly exacerbated. To overcome the issues related to the increase of greenhouse emissions amplifying the global warming, multiple initiatives and engagements have appeared for the last 10 years in order to reduce our global energy demands and reduce the dependency to fossil energy and engage a transition to renewable energy. One way to achieve these objectives is to engage a technological and societal shift in the building industry by reducing energy demands and increasing local energy productions based on renewable energy or, at least, carbon neutral systems. In order to qualify these new types of construction, the concept of positive energy district (PED) has arisen through multiple initiative around the world. This thesis aims to assess the possibility to meet the PED requirements for the new Jakobsgardarna district extension project proposed by Sweco in Borlange, Sweden. This project is based on 144 buildings composed of schools, residentials, retails shop, and offices spread on an 80 ha of land. The Building Energy Modelling (BEM) has been performed on IDA ICE to assess the energy demands and energy production of the entire district following multiple scenarios. These simulations have been performed with either a district heating system or a heat pump as base system. Then, the models have been extended with photovoltaic (PV) panel in multiple configurations in order to find the bes tsolution to meet the PED requirements. First results of the baseline configuration (district heating) shows that the yearly energy demand was around 14,227 MWh which represent almost 69 kWh/m2, mainly dominated up to 75% by the heating demands including domestic hot water (DHW). Moreover, an uncomfortable situation has been met in almost all residential building during summer with temperature reaching up to 31°C. The second configuration considering a heat pump with bore holes in replacement of the district heating shows an overall yearly energy demands of 9,738 MWh representing 47.2kWh/m2 per heated area. This results in a 67% reduction of the energy demands in comparison with the base case. This is due to the high coefficient of performance (COP=4) of the heat pump compared to the district heating system’s (COP=1). In this configuration the heating demands still corresponds to 70% of the overall energy demands. The addition of PV panels compensated the entire electrical needs of the district when combined with district heating and even allowed to reach the positive energy requirements when combined with heat pumps with bore holes. The latter case generates up to 20% of electrical energy in excess of what it produced, even while considering solar panels at a15° of tilt angle in a region where the optimal inclination is defined at 45°. According to the preliminary results obtained in this study, positive energy requirements could be met by the combination of heat pump and PV panels according to our assumptions. This work could then be used to further refine the district design and propose suggestions to improve both the thermal modeling of the district and the design rules for architects and local stakeholders.