Energy renovation of two historical buildings in Mediterranean area

The energy renovation of historic buildings is a particular challenge due to the restrictions and prohibitions related to respecting and preserving their form. Within the European Union, the exclusion of historic buildings from the minimum energy performance requirements until a year ago, lead to the luck of interest for such actions. This case study article presents the applied energy retrofit measures on two historic buildings, the Presidential Palace of the Republic of Cyprus and Loggia, the Town Hall of Heraklion in Greece. Heritage values, normative requirements, operational conditions, and indoor environmental issues, based on site audits and numerical calculations, were considered for selecting the most appropriate interventions. The passive measures include the energy renovation of the openings, an action that was affected by specific requirements of the building conservation authorities of each country. The active measures included for both cases the energy renovation of the existing heating and cooling systems, the integration of RES and the installation of a building energy management system (BEMS). Specific interventions include, for Loggia, the energy renovation of the lighting system, and for the Presidential Palace, the installation of a mechanical ventilation system in the living rooms of the ground floor and charging station for electric cars. The energy savings are equal to 35 % and 49 % for the Presidential Palace and Loggia, respectively. These energy savings correspond to the reduction of 259.9 t and 125.7 t CO₂ emissions.