Study on adaptive comfort behaviours in mixed-mode residential buildings in Tianjin, China

2021 ◽  
pp. 1420326X2110321
Author(s):  
Jing Hou ◽  
Yuexia Sun ◽  
Yangrui Song ◽  
Jungsoo Kim ◽  
Thomas Parkinson ◽  
...  

This paper presents results of a longitudinal field study which aims to investigate adaptive comfort behaviours (i.e. turning on air-conditioner, turning on fans and opening windows or doors) in residential buildings. Field measurements were conducted in 43 homes in Tianjin, northern China, from Spring through early Winter in 2016. Occupants' ‘right-here-right-now' thermal perception and adaptive comfort behaviours were collected through online questionnaires delivered to their smartphones. Results indicated that clothing insulation adjustment was the requisite adaptive behaviour to attain thermal comfort. Clothing insulation was more climate-responsive in Tianjin's autumn than in summer. Statistical models were developed to predict the likelihood of various thermally adaptive behaviours with regard to outdoor air temperatures. An outdoor air temperature of 25.2°C was associated with maximum use of windows/doors for comfort ventilation and minimum use of air conditioning (AC). When outdoor air temperature exceeded 32.5°C, 50% of occupants turned on AC for cooling.

2020 ◽  
Vol 15 (3) ◽  
pp. 163-170
Author(s):  
Rajan KC ◽  
Hom Bahadur Rijal ◽  
Masanori Shukuya ◽  
Kazui Yoshida

The energy use in residential dwellings has been increasing due to increasing use of modern electric appliances to make the lifestyle easier, entertaining and better. One of the major purposes of indoor energy use is for improving indoor thermal environment for adjusting thermal comfort. Along with the use of passive means like the use of mechanical devices, the occupants in any dwellings use active means such as the use of natural ventilation, window opening, and clothing adjustment. In fact, the use of active means when the outdoor environment is good enough might be more suitable to improve indoor thermal environment than the use of mechanical air conditioning units, which necessarily require electricity. Therefore, the people in developing countries like Nepal need to understand to what extent the occupants can use active means to manage their own indoor thermal comfort. The use of active means during good outdoor environment might be an effective way to manage increasing energy demand in the future. We have made a field survey on the occupants’ adaptive behaviors for thermal comfort in a Japanese condominium equipped with Home Energy Management System (HEMS). Online questionnaire survey was conducted in a condominium with 356 families from November 2015 to October 2016 to understand the occupants’ behaviors. The number of 17036 votes from 39 families was collected. The indoor air temperature, relative humidity and illuminance were measured at the interval of 2-10 minutes to know indoor thermal environmental conditions. The occupants were found using different active behaviors for thermal comfort adjustments even in rather harsh summer and winter. Around 80% of the occupants surveyed opened windows when the outdoor air temperature was 30⁰C in free running (FR) mode and the clothing insulation was 0.93 clo when the outdoor air temperature was 0⁰C. The result showed that the use of mechanical heating and cooling was not necessarily the first priority to improve indoor thermal environment. Our result along with other results in residential buildings showed that the adaptive behaviors of the occupants are one of the primary ways to adjust indoor thermal comfort. This fact is important in enhancing the energy saving building design.


2021 ◽  
Vol 39 (5) ◽  
pp. 1483-1490
Author(s):  
Andriyanto Setyawan ◽  
Susilawati Susilawati ◽  
Tandi Sutandi ◽  
Hafid Najmudin

An experiment has been carried out for examining the performance of an air conditioning unit under constant outdoor wet-bulb temperature and varied dry-bulb temperature. During the experiment, the wet-bulb temperature of the compartment for outdoor unit was maintained at 22℃ and the dry-bulb temperature was varied from 24℃ to 36℃. The increase of outdoor air temperature results in the increase of supply air temperature, discharge temperature, suction temperature, and liquid line temperature. These cause the degradation of the air conditioner performance. An increase of power consumption by 1.4% and decrease of cooling capacity by 0.8% were observed for each 1℃ increase of outdoor air temperature. As a result, the energy efficiency ratio drops by 2% for each 1℃ increase of outdoor air temperature.


2021 ◽  
Vol 39 (5) ◽  
pp. 1549-1556
Author(s):  
Ruozhu Wang ◽  
Ruting Ma ◽  
Guang Hong ◽  
Wei Tian ◽  
Yongmei Qian

Utilization of energy has boosted socio-economic development but meanwhile exacerbated the environmental problems. Offshore areas in China boast abundant solar energy resources. The present work explores the application of solar energy in offshore residential buildings and the ways for integration of solar collectors with the buildings to analyze the potential impact of installation of solar collectors on the design of offshore residential buildings. An extensive design approach that introduces protruding features, outdoor air-conditioner unit spaces, and “virtual” elements into design of residential buildings was proposed, which would integrate the solar collectors into the architectural design and extend the functions of the residential buildings. This research aims to provide a theoretical basis for promoting utilization of solar energy and integrated design of offshore buildings.


Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3359
Author(s):  
Hanan S. S. Ibrahim ◽  
Ahmed Z. Khan ◽  
Waqas Ahmed Mahar ◽  
Shady Attia ◽  
Yehya Serag

Retrofitting heritage buildings for energy efficiency is not always easy where cultural values are highly concerned, which requires an integrated approach. This paper aims to assess the potential of applying passive retrofitting scenarios to enhance indoor thermal comfort of heritage buildings in North Africa, as a hot climate, a little attention has been paid to retrofit built heritage in that climate. A mixed-mode ventilation residential building in Cairo, Egypt, was selected as a case study. The study combines field measurements and observations with energy simulations. A simulation model was created and calibrated on the basis of monitored data in the reference building, and the thermal comfort range was evaluated. Sets of passive retrofitting scenarios were proposed. The results (based on the ASHRAE-55-2020 adaptive comfort model at 90% acceptability limits) showed that the annual thermal comfort in the reference building is very low, i.e., 31.4%. The application of hybrid passive retrofitting scenarios significantly impacts indoor thermal comfort in the reference building, where annual comfort hours of up to 66% can be achieved. The originality of this work lies in identifying the most effective energy measures to improve indoor thermal comfort that are optimal from a conservation point of view. The findings contribute to set a comprehensive retrofitting tool that avoids potential risks for the conservation of residential heritage buildings in hot climates.


2020 ◽  
Vol 9 (2) ◽  
pp. 50-62
Author(s):  
Laina Hilma Sari ◽  
Izziah Hasan ◽  
Erna Meutia

 The Baiturrahman Grand Mosque is well-known as the identity of Banda Aceh town, Indonesia. The extensive renovation was carried out in 2015 to the Mosque, presenting an open piazza coated with glossy white marble replacing the previous greeneries and grass. This change creates a much different thermal sensation of the prior environment. This condition also invites the contrast to respond and define spatial comfort, including thermal and visual comfort. Therefore, this study conducts an assessment of thermal and visual comfort at the open piazza, which was done through field measurements. The outdoor thermal comfort was calculated using the equations proposed by Sangkertadi that are appropriate for the tropics. The visual comfort was examined using the De Boer glare scale. The result shows the discomfort appearance for both thermal and visual comfort. The study gives recommendations, such as planting greeneries, providing more shades for achieving lower outdoor air temperature. Replacing the glossy marble with the diffusing and rough surface will reduce the glare for getting the more acceptable visual comfort against the marbles.


2020 ◽  
Vol 12 (14) ◽  
pp. 5741 ◽  
Author(s):  
Sheikh Ahmad Zaki ◽  
Siti Wan Syahidah ◽  
Mohd Fairuz Shahidan ◽  
Mardiana Idayu Ahmad ◽  
Fitri Yakub ◽  
...  

This study investigated the variation of outdoor air temperature in the shaded area covered by buildings in an urban university campus in Malaysia. In-situ field measurements were conducted to measure the distribution of outdoor air temperature at eight different locations for seven days. Meanwhile, the building-induced shadows were generated using the AutoCAD Revit software to investigate the air temperature change. The study used four urban morphological parameters namely building to greenery ratio, sky view factor (SVF), and height-to-street width (H/W) ratio. The relationship between building-induced shadow and outdoor air temperature (Tout) obtained from the in-situ measurement was investigated. The results showed that the building-induced shadows could lower air temperature. It can be noted that a high ratio of building to greenery resulted in a higher air temperature. In contrast, the area with a low SVF value due to the combination of prolonged shading by buildings and trees had a lower air temperature. Thus, the area with a high building ratio, low greenery ratio, higher SVF value, and low H/W ratio potentially has a higher outdoor air temperature. Conclusively, combination of building shading created by appropriate ratio of building morphology and sufficient greenery able to improve the microclimate of a campus area.


2020 ◽  
Vol 13 (1) ◽  
pp. 201
Author(s):  
Pau Chung Leng ◽  
Gabriel Hoh Teck Ling ◽  
Mohd Hamdan Ahmad ◽  
Dilshan Remaz Ossen ◽  
Eeydzah Aminudin ◽  
...  

The provision requirement of 10% openings of the total floor area stated in the Uniform Building By-Law 1984 Malaysia is essential for natural lighting and ventilation purposes. However, focusing on natural ventilation, the effectiveness of thermal performance in landed residential buildings has never been empirically measured and proven, as most of the research emphasized simulation modeling lacking sufficient empirical validation. Therefore, this paper drawing on field measurement investigates natural ventilation performance in terraced housing with an air-well system. The key concern as to what extent the current air-well system serving as a ventilator is effective to provide better thermal performance is to be addressed. By adopting an existing single-story air-welled terrace house, indoor environmental conditions and thermal performance were monitored and measured using HOBO U12 air temperature and humidity, the HOBO U12 anemometer, and the Delta Ohm HD32.3 Wet Bulb Globe Temperature meter for a six-month duration. The results show that the air temperature of the air well ranged from 27.48 °C to 30.92 °C, with a mean relative humidity of 72.67% to 79.25%. The mean air temperature for a test room (single-sided ventilation room) ranged from 28.04 °C to 30.92 °C, with a relative humidity of 70.16% to 76.00%. These empirical findings are of importance, offering novel policy insights and suggestions. Since the minimum provision of 10% openings has been revealed to be less effective to provide desirable thermal performance and comfort, mandatory compliance with and the necessity of the bylaw requirement should be revisited.


2020 ◽  
Vol 13 (1) ◽  
pp. 255
Author(s):  
Luciano C. de Faria ◽  
Marcelo A. Romero ◽  
Lúcia F. S. Pirró

Improving indoor environment quality and making urban centres in tropical regions more sustainable has become a challenge for which computational models for the prediction of thermal sensation for naturally ventilated buildings (NVBs) have major role to play. This work performed analysis on thermal sensation for non-residential NVBs located in Brazilian tropical warm-humid climate and tested the effectiveness of suggested adaptive behaviours to mitigate warm thermal sensation. The research method utilized transient computational fluid dynamics models coupled with a dynamic model for human thermophysiology to predict thermal sensation. The calculated results were validated with comparison with benchmark values from questionnaires and from field measurements. The calculated results for dynamic thermal sensation (DTS) seven-point scale showed higher agreement with the thermal sensation vote than with the predicted mean vote. The test for the suggested adaptive behaviours considered reducing clothing insulation values from 0.18 to 0.32 clo (reducing DTS from 0.1 to 0.9), increasing the air speed in 0.9 m/s (reducing DTS from 0.1 to 0.9), and applying both suggestions together (reducing DTS from 0.1 to 1.3) for five scenarios with operative temperatures spanning 34.5–24.0 °C. Results quantified the tested adaptive behaviours’ efficiency showing applicability to improve thermal sensation from slightly-warm to neutral.


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