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Courtyards are building elements that originated from the hot dry regions, are amongst the
oldest architecture footprint that have been used in buildings by human and now has gained wide
acceptance in various parts of the world. The geometry of the courtyard form affects considerably the
shadows produced on the building envelope, and consequently the received solar radiations and the
cooling and heating loads of the building. In recent years, there has been a growing interest in the
design of courtyards for the microclimatic enhancement of outdoor spaces. However, there is still little
knowledge regarding the thermal performance characteristics of courtyards, particularly in hot and
humid climates. This study reviews and evaluates the available literature on courtyards for providing
thermally comfortable outdoor spaces and analyse and discuss the results of a simulation study
performed according to different design configurations and scenarios of orientations and use of
vegetation in an enclosed courtyard space to optimize courtyard orientation and acceptable vegetation
densities for maximum thermal comfort.

The software ENVI-met 4.4, a three-dimensional fluid dynamics microclimate software is used as a tool
to carry out the parametric studies for simulating the outdoor thermal performance of an enclosed
courtyard in the hot and humid climate of Tiruchirappalli, India, for an identified hot day and building
occupancy period. This software provides the platform to model the surface- plant- air interactions in
urban spaces with a typical resolution from 0.5 to 10 m in space and 1 to 10 s in time. ENVI-met requires
detailed inputs related to the meteorological data, building, vegetation and soil characteristics. Five
different permutations of vegetation densities and subsequently 10 orientations of courtyard are
simulated for outdoor thermal performance and comfort. Comparison of the simulated results is done
on the basis of shadow analysis, air temperature, wind speed, relative humidity and mean radiant
temperature. Also, the Physiologically Equivalent Temperature (PET) index allowed to further explore
the thermal comfort conditions of the courtyard space. As a result, guidelines are proposed to optimize
the design of courtyards based on their vegetation densities and orientation towards enhancing their
thermal performance characteristics.

It is important to take into consideration the orientation and location during the early design stage of
courtyards. The results of the study suggest that a major change in the thermal performance of the
courtyard can be achieved by properly orienting the building and the courtyard to achieve maximum
internal shading, better wind speeds and controlling humidity. Even though increasing the use of trees in
courtyards directly results in an increased level of relative humidity inside the courtyard space and
reduction in wind movement, it was observed that an abundance in the amount of vegetation in the
courtyard can help achieve an acceptable level of thermal comfort in the region and may be used by its
users for a larger proportion of courtyard area and duration of occupancy period. Finally, this paper stresses that only well-designed courtyards and landscapes may represent a viable option for
sustainable built environments.

Keywords: courtyard, microclimate modifier, mean radiant temperature, physiologically equivalent
temperature

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