Cool roof and ventilation efficiency as passive cooling strategies for commercial low-rise buildings - ground thermal inertia impact

• Published in: Advances in building energy research Vol. 7; no. 2; pp. 192 - 208
• Main Authors: Lapisa, Remon, Bozonnet, Emannuel, Abadie, Marc Olivier, Salagnac, Patrick
• Format: Journal Article
• Language: English
• Published: London Taylor & Francis 01.10.2013; Taylor & Francis Ltd
• Subjects: Buildings; Case studies; commercial building; Commercial buildings; cool roof; Cooling; Efficiency; Grounds; Heat; Inertia; Low rise buildings; Mathematical models; Roofs; Specific heat; thermal building simulation; thermal inertia; ventilation; France
• ISSN: 1751-2549; 1756-2201
• DOI: 10.1080/17512549.2013.865559

Commercial low-rise buildings are often characterized by weak energy performances, and heat transfers through roof and ground are prevalent. The roof design and its opening system is a key factor of the thermal performance. Skylights and radiative properties of roof coating have a direct impact on solar gains, thermal losses and natural ventilation potential. The overall performance depends on the combination of these design parameters (solar reflectance and opening size), on the weather conditions and on the inertia given by the slab on the ground. The roof design performance depends on the ground which determines the dynamic behavior of these buildings. A generic case study is modeled and an extensive parametric study (about 840 annual simulations) is performed to point out these key parameters' impacts on energy demand and comfort. The combination of efficient roof techniques (skylights and cool roof) along with a high thermal inertia of the building can be an adequate passive cooling solution in summer, with a 99.8% drop in degree-hours above the discomfort temperature in summer. Nevertheless, we show that these passive strategies could not be totally efficient without taking care of the ground thermal inertia which account up to 58.6%.