Operational energy use versus LCA : case study The Mobble for Solar Decathlon Europe 2019 competition

Studies have shown that the building sector is the biggest contributor to global warming, generating 40 to 50 % of the global output of greenhouse gas emissions. Furthermore, this industry consumes up to 40 % of the materials entering the global economy and produces one third of the total waste. In Belgium alone, estimations put the building sector’s waste output at fifteen million ton of construction waste on a yearly basis. Therefore, a more environmental-friendly thinking is required, that also considers the impact of construction materials on the environment. For highly insulated buildings the environmental impact of additional construction materials might supersede the reduction in energy use that can be obtained throughout its service life. A trade-off should be made between the embedded and operational energy. For the Solar Decathlon competition 2019 in Szentendre an energy efficient house The Mobble was designed and built, for which detailed dynamic energy simulations were performed in Modelica/Dymola, and as well, a life cycle assessment was done using the simulation software Simapro. Even so, the potential of Personal Comfort Systems (PCS) is investigated through the energy simulations. The result of the trade-off for this case-study shows on the one hand a clear potential of advanced demand control HVAC systems and on the other hand clear limits to the increase of insulation thickness. However, for this specific case it was shown that the optimal insulation thickness from environmental point of view is still well above the minimum requirement in the Belgian building code, even for very efficient HVAC systems

SHERPA Position Paper - Empowering rural areas in multi-level governance processes

This SHERPA Position Paper builds on the contributions of all 41 SHERPA Multi-Actor Platforms (MAPs) involved in the fourth (and final) cycle of the SHERPA project. During this final cycle, MAPs were asked to reflect on how to empower regional and local institutions and actors in multi-level decision-making processes in rural areas, and propose recommendations for policy and future research on this topic. Each MAP discussed the elements they found most relevant for their geographical area in relation to multi-level governance in rural areas, and used this as their MAP input for the development of this Position Paper. More information on this topic from each individual MAP can be found in the MAP Fiches

Optimization of insulation levels from an environmental perspective : impact of HVAC controls and Personal Comfort Systems

Today, strict insulation requirements apply. Nevertheless, the inverse correlation of thermal conductivity with insulation thickness leads to decreasing energy savings with increasing insulation packages. Therefore, a balance between potential energy savings and environmental impact due to additional materials using Life Cycle Assessment (LCA) needs to be strived for. This balance is sought for a case study called ‘The Mobble’ i.e. a flexible, modular, and circular building system developed by a student team from Ghent University. Through an iterative design process supported by LCA, comfort and dynamic energy simulations efforts are made to design an energy-efficient and low impact module with an agreeable indoor environment. First, material choices are made based on LCA and the material impact of a 5-module home is calculated. Second, energy calculations are executed in Modelica/Dymola. For this, three possible energy reductions are explored: insulating the building, altering the working regime of the HVAC system and lowering the setpoint temperature while maintaining comfort by using personal comfort systems (PCS). The results support PCS as a possible energy conservation measure and indicate that reducing operational energy does not shift the environmental burden to the additional materials’ production. However, these environmental saving effects decrease as the operational share decreases

Balancing environmental impact, energy use and thermal comfort : optimizing insulation levels for The Mobble with standard HVAC and personal comfort systems

The energy crisis in the 1970s led to increasingly stricter building codes, resulting in the currently required nearly zero-energy buildings. Nonetheless, the energy saving potential of further increasing insulation packages decreases as a result of the inverse correlation of thermal transmittance with insulation thickness. Therefore, a balance is required between the potential energy savings and the material impact using Life Cycle Assessment (LCA). This balance is studied for a demonstration building called 'The Mobble'. For the LCA, the Ecoinvent database and impact assessment method ReCiPe H/A (2016) are used. For the potential energy savings dynamic energy simulations are run in Modelica/Dymola. To ensure equal comfort, thermal comfort is modelled using Human Thermal Module. An optimisation using the trade-off between material impact and operational energy by considering the optimal insulation thickness is executed on three levels: (1) building envelope (insulation, glazing type), (2) HVAC system efficiency (constant, demand based, personal comfort systems) and (3) electricity mix. This additionally enables to assess the robustness of imposing strict insulation requirements in e.g. building codes. The results show that even when extremely advanced demand based systems are adopted, the optimal insulation thickness ranges between 22 cm and 28 cm and is thus hardly affected, neither by user behaviour. However, the choice of energy mix does have a considerable impact on this optimal insulation thickness, and entails a shift in optimal insulation thickness from 20 cm -30 cm-10 cm -20 cm when a lower environmental impact for the electricity mix is considered (compared to the current Belgian electricity mix)