Extending the adaptive thermal comfort models for courtyards

Eduardo Diz-Mellado,Victoria Patricia López-Cabeza,Carlos Rivera-Gómez,Carmen Galán-Marín,Juan Rojas-Fernández,Marialena Nikolopoulou

doi:10.1016/j.buildenv.2021.108094

Eduardo Diz-Mellado, Victoria Patricia López-Cabeza + Show 4 more

Open Access

https://doi.org/10.1016/j.buildenv.2021.108094

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Abstract

Temperatures in Mediterranean cities are rising due to the effects of climate change, with a consequent increase in the heat waves frequency. Recent research has shown the tempering potential of semi-outdoor spaces such as courtyards, which are semi-enclosed spaces that are widely used by the users of buildings in Mediterranean cities. International standards addressing thermal comfort parameters provide technical guidelines for indoor spaces only. Expanding this concept, this paper focuses on the potential to extend and interpret the existing calculation models for indoor thermal comfort, EN 16798 and ASHRAE 55, to determine thermal comfort, monitoring two different courtyards in Cordoba, Spain, during both typical summer and heat wave periods. The results show that during the typical summer, the monitored courtyards can reach temperatures up to 8.4 °C cooler than outside. Subsequently can be considered to be in thermal comfort on average for 88% of the time according to EN 16798, and 75% according to ASHRAE 55, which drop to 71% and 52% respectively during heat wave (HW) periods, in spite of increasing thermal gap (TG) up to 13.9 °C. The results are also compared with the PET indicator used for evaluation of outdoor thermal comfort, which provides comparable figures: 81% summer and 73% HW. Implications of implementing passive shading strategies to increase comfort in these transition spaces are also evaluated. The research highlights the thermal potential and usefulness of courtyards in warm climates, so they can ultimately be included in the building analysis as a potentially comfortable and habitable space.

Highlights

The increase in global average temperatures has become a major issue in recent decades, as well as the human perception and adapt ability considering air quality and comfort temperatures [1]
The analysis presents the Diurnal Thermal Range (DTR) for the external envi ronment compared to the two courtyards for five days for a typical summer week (Fig. 6a) and for the heat-wave (Fig. 6b)
The results have focused on the thermal gap (TG) generated by the courtyard microclimate, i.e. the temperature difference between maximum outdoor temperature (MOT) and courtyard temperature (CT), defined by the following Equation (3)

Summary

Introduction

The increase in global average temperatures has become a major issue in recent decades, as well as the human perception and adapt ability considering air quality and comfort temperatures [1]. Previous studies based on surveys carried out in European countries show the relationship be tween indoor comfort and outdoor temperature in buildings in free-running mode, with the indoor comfort temperature increasing along with the outdoor temperature [7] This is not the case in HVAC buildings [8], where the thermal environment is strictly controlled; so thermal comfort is greatly influenced by the architectural design of buildings, the building services, and their operation [9]. Taking into account the users’ comfort, quantifying the energy required to make buildings comfortable has a direct impact on the environment [6] In outdoor environments, these have been analysed in terms of their thermal comfort and suitability [10], the social and economic impact on certain cities [11], as well as aspects related to the health level of the

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