Passive and active solutions to improve the energetic efficiency of buildings

Abstract

Today the building sector has a significant weight in energy consumption and a high potential for increasing its energy efficiency. With the enforcement of the energetic certification, it has been tried to find and select different solutions that presents less energy consumption and waste, which translates into an effective reduction of CO2 emissions. It is in this perspective that this work fits, since its main aim is to evaluate the contribution of passive and active solutions of a hotel for the improvement of the energetic efficiency, as well as to evaluate the contribution of some renewable energy sources. Within them, the contribution of solar systems for hot water heating and electric energy production has been approached. Despite the importance assumed by using renewable energies in the buildings sector, cogeneration remains as the most effective technology on the conversion of primary energy into electricity and heat. The application of cogeneration technologies in the buildings sector gains notability facing the rise of fuel prices and the need to ensure adequacy and comfort of spaces. Relatively to the practical case in study, the building is a hotel located in Portugal. Multizone dynamic codes for simulations were used. To improve the building performance, there were made several changes on the model with the goal of evaluating the contribution of different solutions, either at passive and active level, in order to increase the energetic efficiency of the hotel. It was concluded that they contribute to a reduction of thermal needs of 25.2% and avoided emissions of equivalent tons of CO2 of 30.4%.The analysis of the technical/economic viability of the implementation of the CHCP becomes executable, using a system based on an internal combustion engine that runs with natural gas, with an absorption chiller to produce cooling. The payback period of this solution is less than 8 years which proves that there is an economic viability of this technology.