Assessing energy performance and indoor comfort in maltese places of worship

Resumen

Buildings are responsible for more than 40% of the total energy consumption and greenhouse gas emissions in Europe. As a result, the EU has enacted several rules aimed at increasing energy efficiency and limiting the growth of energy demand. However, it is pertinent to point out that places of worship are exempt from getting an energy rating certificate under the European Union Energy Performance in Buildings Directive 2010/31/EU. Malta is completely reliant on imported energy supplies due to a lack of fossil fuel resources. This, to the cost of national security, price volatility, political and environmental concerns, amongst other things. Controlling and managing energy use in buildings is one efficient strategy to reduce this reliance. Excessive energy flow through the building envelope and, unregulated use of air-conditioning are some common drivers of energy waste in buildings. This thesis aims to assess the energy performance of places of worship and combine it with indoor comfort analysis. Passive measures to improve internal comfort levels are identified and prioritised to address heat transfer through the building envelope and mitigate the emerging trend of installing air-conditioning systems. This study takes into consideration the status quo of various places of worship of different building eras using a monitoring programme for temperature and humidity within these buildings. It further delves into the social aspect of how worshipers perceive the indoor comfort through questionnaires addressed to the occupants. Subsequently, it analyses how passive measures can improve the indoor ambient conditions through software design modelling using DesignBuilder-Energy Plus software. This analysis show that historic church structures outperform expectations. The heritage building typology provides promising possibilities for lowering energy consumption, maintaining balanced environmental conditions for artifacts, and meeting occupant comfort standards. The findings pertaining to the monitoring program demonstrate that the church buildings under study, representing the 17th to mid-18th century Baroque period, are termed as thermally comfortable in accordance with the EN16798-1 standard category 3 comfort limits. Moreover, results exhibit the capacity of their heritage construction typology, to maintain balanced environmental conditions when compared to the fluctuated indoor VII temperatures in the contemporary churches. The latter, pertaining to the more contemporary construction methodologies of the churches, jeopardises their thermal comfort, having recorded temperatures exceeding the broadest comfort range limits. Findings through statistical analysis of both quantitative research based on indoor measurable data and qualitative research based on replies to questionnaires from churchgoers, also show that there is a significant correlation between the actual thermal comfort levels measured in accordance with the EN 16798-1 standard and the expected thermal comfort experienced by congregants in most of the parish churches under review. The implementation of passive measures within selected churches, particularly the implementation of solar control strategies that improves the building envelope's thermal performance, significantly decreased heat discomfort. The outcome highlights differences between diverse types of church buildings, depending on their era, site constraints and methodology of construction, together with a list of passive and non-intrusive recommendations for enhancing the comfort of worshipers and improving the energy efficiency aspects of these buildings, whilst respecting their architectural heritage and artefacts with which they are adorned.