Optimization of Architectural Thermal Envelope Parameters in Modern Single-Family House Typologies in Southeastern Spain to Improve Energy Efficiency in a Dry Mediterranean Climate

Abstract

The increasing regulatory requirements for energy efficiency in Europe imply a significant increase in insulation and solar control of buildings, especially in hot and semi-arid climates with high annual insolation such as the Spanish Mediterranean southeast. The consequences in architectural design to optimize compliance with the new technical and regulatory requirements of nearly zero-energy buildings are high. This paper analyzes the energy performance of a modern single-family house on the Spanish Mediterranean coast. The objective is to determine which design parameters most influence the energy improvement of this case study in order to establish design strategies that can be generalized to other new construction or energy retrofit projects, taking into account the specific characteristics of the warm and semi-arid Mediterranean climate. The scientific novelty of the work is to demonstrate that the design criteria of most modern single-family houses built or rehabilitated in the Spanish Mediterranean in the last decade comply with the energy efficiency requirements of Directive 2010/31/EU but are not specifically adapted and optimized for the special characteristics of the dry Mediterranean climate. This is the case of the house studied in this paper. The methodology used consisted of a systematized study of the main construction and geometric parameters that most influence the thermal calculation of this project: the thermal insulation thickness, thermal transmittance of the glazing, solar control of the glazing, total solar energy transmittance of the glazing with the movable shading device activated, size of glazing and the size of façade overhangs. The results obtained show that the use of mobile solar protection devices in summer, such as awnings or blinds, reduces the cooling need in summer up to 44% and the overall annual energy need (Cooling + Heating) up to 20%. This implementation is more efficient than increasing the thermal insulation of facades and glazing, reducing the size of windows or increasing overhangs. The most optimal solution is the simultaneous modification of several parameters. This reduces both heating need in winter and cooling need in summer, achieving an overall reduction in an annual need of 48%. This multiple solution improves the annual energy performance of the house much more than any solution consisting of modifying a single individual parameter. The results determine trends, explanations and deductions that can be extrapolated to other projects.