Reviewing the thermal and microclimatic function of courtyards

Abstract

Currently, sustainability is one of the most important subjects in architecture and urban design. Sustainable design strategies reduce energy consumption of buildings and environmental pollution. Moreover, these strategies improve the microclimatic conditions of urban spaces. In this regard, courtyard design is an efficient sustainable strategy to improve thermal and microclimatic conditions of urban spaces. For 5000 years, courtyards have been developed to adapt to severe climatic conditions, particularly in hot and arid climates. Inaccurate courtyard thermal estimations may occur due to the complexity of optimal thermal design and insufficient tools for simulating the thermal conditions of indoor and outdoor spaces simultaneously. In the last four decades, researchers have recommended several methods to study the thermal function of courtyards. Although the variety of the modelling particularities makes it difficult to obtain appropriate results that encompass all influential factors of courtyard climatic performance, this paper provides a comprehensive review of the papers of this type of building form. The main goal is to clarify if and how the construction of courtyards can decrease energy consumption and improve the microclimate of buildings. The present study focuses on the impact of courtyard design factors (such as proportion, orientation, geometry, opening characteristics, and material) and its components (such as shading devices, vegetation, and water pool) on energy consumption, indoor and outdoor temperatures, solar radiation, and natural ventilation in different climates. Regarding the researchers’ frameworks in the reviewed papers, three main categories are identified: 1- those examining the microclimatic function of courtyards, 2- those based on the thermal function of courtyards, and 3- those that incorporate an integrative approach (considering the thermal and microclimatic functions of courtyards simultaneously). Afterward, the paper reviews the role of three main climatic factors — solar gain, humidity, and natural ventilation — in each category.