Evaluation of Energy Rehabilitation Strategies for a Historical Courtyard Building

The rapid climatic change derived from GHGs emissions requires a substantial reduction in energy consumption, not only for new constructions, but also through energy rehabilitation of existing buildings. Residential buildings in Italy cover more than 80% of the total building stock. In particular, 20% of housing consists of buildings built before the '900, many of these historic buildings are subject to constraints of historical integrity which prohibits major alterations. The present work is related to energy rehabilitation of a historical building dating back to '400. The building complex understudy is a residential courtyard building and is located in the province of Verona. This building is an example of energy retrofit carried out in accordance with the original architectural features and preservation constraints. For energy rehabilitation of the complex, the strategies have been focused on the building envelope and energy supply systems respecting both the regulatory constraints imposed by preservation of historical buildings and, where possible, the current national legislation about the building energy efficiency. This good result was achieved only through the identification of best solutions based on mutual compatibility and optimization on the thermo-physical characteristics of the building and the HVAC systems. The interventions on the building are focused on the use of thermal inertia of the original massive masonry walls, increased insulation of opaque (vertical walls and roof) and transparent surfaces, and the use of a high efficiency HVAC system e.g. ground water heat pump integrated with radiant floor panels and a dehumidification system for humidity control in summer period. As a result, the overall energy performance of building is improved substantially. The thermal performance of building for both winter and summer periods have been evaluated by dynamic computer simulations. The estimated energy demand and peak powers have been verified in relation to the envelope technology and HVAC systems considered in the study. Comparing the initial state and the final choice of building envelope, a reduction of approximately 60% on heating energy demand is achieved.