Adaptive comfort criteria in transitional spaces: a proposal for outdoor comfort

Urban Heat Island (UHI) as a combined consequence of global warming and the cities diameter increase, continues to be technological challenges today. Different passive strategies related to the buildings and cities architecture design imply energy demand reduction achieving. Architectural elements such as courtyards become extraordinarily significant as passive cooling systems. The research aims to establish patterns and values of adaptive comfort in transition spaces, reflected in the thermal regulation capacity of these buildings thanks to the morphology of the courtyards, contributing also to possible state strategies for action in favor of reducing the effects of climate change

Thermal Sensation in Courtyards: Potentialities as a Passive Strategy in Tropical Climates

Climate change will bring changes to our living conditions, particularly in urban areas. Climate-responsive design strategies through courtyards can help to moderate temperatures and reduce the thermal stress of its occupants. Thermal response inside courtyard is affected not only by its morphological composition but also by subjective factors. Thus, standardized thermal scales may not reflect the stress of the occupants. This study investigated the impact on thermal attenuation provided by a courtyard located in a tropical climate under extreme cold and hot synoptic conditions by means of local thermal sensation scales. Microclimatic variables were monitored, simultaneously with the application of a thermal comfort questionnaire, by using weather stations installed outside and inside the courtyard. The Modified Physiological Equivalent Temperature Index (mPET) was utilized to predict the heat stress. Calibration was conducted using linear regression to attribute particular thermal sensation votes to correspondent mPET values. It was found that thermal sensation can be affected by factors such as psychological, behavioral, and physiological. The courtyard’s form provides a passive cooling effect, stabilizing interior thermal sensation, with attenuation peaks of 6.4 °C on a cold day and 5.0 °C on a hot day. Courtyards are an alternative passive strategy to improve thermal ambience in tropical climate, counterbalancing climate change

Tempering potential-based evaluation of the courtyard microclimate as a combined function of aspect ratio and outdoor temperature

Courtyards are traditional construction models in Mediterranean cities. In this research, tempering performance of courtyards during a two-year field monitoring campaign in southern Spain was investigated. The main objective was to identify the thermal functions of inner courtyards, analyzing the aspect ratio (AR) and the influence of outdoor temperature to offer a perspective that contributes to the development of passive cooling strategies for urban housing. This investigation also reviewed these climate modifiers, in light of the average lifespan of a building, to establish thermal tempering guidelines to mitigate the effects of climate change. The results show that, although the AR is a determining factor in maximizing the courtyard tempering potential, other parameters such as diurnal temperature range (DTR) or maximum outdoor temperature (MOT) can significantly modify the influence of the AR. The study demonstrates these interactions verifying, for the climates studied, that courtyards with AR > 3 are appropriate solutions, especially in the warmest zones, enhancing microclimate management in summer. Results evince that courtyard maximum thermal performance is related to MOT increase. This factor is crucial to establish a tempering initial potential for a given courtyard. Apart from this, a complete daily cycle analysis through DTR confirms and clarifies this thermal buffer effect

Extending the adaptive thermal comfort models for courtyards

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

Sample key features affecting mechanical, acoustic and thermal properties of a natural-stabilised earthen material

The use of natural materials has become more important as a result of the growing need to conserve energy, exploit renewable materials, and incorporate architecture and construction into sustainable methods of production. Accordingly, the present work investigates the engineering properties of a new earthen building material. This proposal is based on traditional unfired earthen masonry and consists of compressed earth blocks stabilised with natural polymers and wool fibers for use as insulating and structural load-bearing walls in buildings. The conducted experimental study enabled us to determine the mechanical performance, thermal conductivity, noise mitigation, modulus of elasticity, porosity percentage, and diameter through mercury intrusion porosimetry. The influence of soil characteristics on thermophysical and acoustic properties of tested material were investigated. The experimental data show good efficiency and a significant improvement in the engineering properties of these materials compared to traditional compressed earth blocks. In this research, a comprehensive analysis of the interaction of different properties is proposed as an assessment methodology that could be applied to any kind of stabilised soil material. The correlation of the results, being the type of soil the only variable of the analyzed samples, has allowed identifying sample key features and tests so as to obtain the best mechanical, thermal and acoustic performances

Comparative evaluation of passive conditioning strategies for the improvement of courtyard thermal performance

The alarming increase in global average temperatures and the adaptive capacity of humans in relation to air quality and temperature are becoming increasingly relevant. Scientific resources have focused on the thermal adaptation of building users, but little research has been done on thermal comfort in outdoor and semi-outdoor spaces in the city. This study focuses on the analysis and comparison of different passive strategies implemented in courtyards. The present investigation quantifies the comfort improvement brought by shading and misting elements in courtyards. For this purpose, a set of intrinsic and extrinsic variables that intervene in the thermodynamic behavior of the courtyard will be taken into account. The relevance of the study lies not only in the need to design energy-efficient buildings with adequate thermal comfort patterns but also in more resilient urban environments in the current climate change scenario. The main objective of the research is to quantify the implementation of other passive strategies and the results of different combinations of these. The results identified a thermal delta in the courtyard of up to 10°C cooler than the outdoor temperature, which varies depending on the different strategies implemented and the time of day

Assessing the impact of courtyards in cooling energy demand in buildings

Sustainable passive design strategies can reduce the energy consumption of buildings. In this regard, inner courtyards act as microclimate modifiers that enhance the perception of comfort in the surrounding environment. The present study, through a pooled analysis of experimental and numerical data, intends to assess the beneficial effect that the courtyards have in reducing the energy consumption of the buildings, especially for cooling demand. Accordingly, a new methodology allowing the use of different experimental data for facades and courtyards in software tools for the assessment of the real energy performance of buildings with courtyards is proposed. Besides, a detailed example of the application of the proposed methodology is performed for two scenarios simultaneously: a case study (considering the courtyard effect on the air temperature) and a reference one (without considering this effect). From the results, it is found that the courtyard reduces the demand for cooling in the spaces bordering it. As expected, the magnitude of the cooling demand reduction is correlated to the floor level, is increased at lower floors in the courtyard building. This relative reduction is up to 11%, being, for the case study analyzed, an average reduction of 7%

Cross-evaluation of thermal comfort in semi-outdoor spaces according to geometry in Southern Spain

Climatic events in Mediterranean cities, such as heat waves, directly affect their inhabitants. As a result, outdoor thermal comfort in urban spaces is gaining increasing research attention because it is associated with the quality of life in these cities. Significant improvements have been achieved in the adaptation of buildings; however, a similar level of resilience to climate is not observed in urban spaces. This research proposes quantifying thermal comfort in semi-outdoor enclosed spaces according to EN16798, UTCI and PET. The study is carried out in different cities in southern Spain, employing 20 courtyards with different geometries. Results reveal courtyards as liveable rooms during most hours of the day in summer. The influence of its geometry considering AR is decisive since the impact of outdoor climate on the microclimate of the courtyard depends on it, exceeding values of 60% comfort hours (PET and EN16798) in all case studies during the warm season. When AR > 3, the courtyard reaches comfort 90–100% of the hours of the day and approximately 70–80% when the AR 2–3. In the case of the most common geometries in Mediterranean cities, with AR 1–2, >70% of the hours the courtyards are within the limits of comfort