LCC and LCA for Low Temperature Heating Integrated with Energy Active Envelope Systems

Sammanfattning: Windows has been always considered as heat sinks and they can account more than 25% of a building envelope. For this reason, its design and performance in dwellings play a major role in regulating the indoor environment. The construction sector has been investing in better insulation envelope systems for the last decades to reduce the heat transmissions losses and energy consumption in households. LOWTE is a Swedish firm specialized in low energy building components and due to all these facts, it has recently developed a double slot energy active envelope window (EAW) for improving energy-saving in buildings. EAW is a window prototype that integrates low-temperature heating and energy active systems, and it is planned to be installed at Testbed KTH in Stockholm (Sweden). Waste heat from the current heating systems will be used during its whole operation. Then, a life cycle assessment (LCA) will be accomplished for evaluating EAW feasibility and costeffectiveness before its implementation. Furthermore, an LCA comparison with other two passive window systems will be made. A double-glazed and a triple-glazed window will represent the reference system and a competent alternative solution, respectively. A sensitivity analysis for each model will be developed in order to consider multiples scenarios and obtain which variables affect the most EAW profitability. Thus, the feasibility of the EAW would be studied from an economic and environmental perspective. The simulations of both models show the potential that EAW can represent for the current heating system in KTH Live-In-Lab apartments. Since EAW is quite subjected to the thermal conditions of the room, the ambience, and the internal flowing air; costs savings and avoided environmental impacts will depend mainly on the thermal performance of the whole system.