Design and experimental study of a low-cost prefab Trombe wall to improve indoor temperatures in social housing in the Biobío region in Chile

A renewed interest in bioclimatic strategies for building retrofitting is noticed because more than 40% of the total annual world energy consumption is used in buildings. In Chile, the social housing stock is more than 5.5 million units built with government subsidies. Thermal regulations improvement started in 2000, nevertheless, solar passive strategies are still not present on the immediate retrofitting agenda. The Bioclimatic Prosthesis Project aims to design-develop prefabricated small scale passive solar systems for the refurbishment of social housing reducing their energy use. These systems should be affordable and easy to build and install. This paper focuses on an adaptable and low-cost prefabricated Trombe wall with a vertical storage system. Mobile insulation during winter nights and external shading during summer were also tested. The system was built and installed in a test cell similar to the most used area of a social housing. The thermal efficiency of it, was monitored and compared to a similar test cell without the passive component. Two different microclimate scenarios were tested: in the coast and in the interior valley. Results show the addable Trombe wall can reduce energy demands and winter firewood consumption by nearly 33%, increasing the indoor temperature in 5 °C in the better cases measured during the cold season. In winter, the indoor thermal comfort hours are increased by 69.35% for the city in the central valley (Chillán). For the coastal city (Coronel), the results were 56.29%. In summer, the comfort hours were also increased by 10% on the coast, and in almost 19.5% in the interior valley, adding an external shading element to solve the overheating risk.status: Published onlin