A thermal performance study of four communities in Ghana's savannah region

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Christian Koranteng ◽  
Barbara Simons ◽  
Frederick Wireko Manu

PurposeMany countries the world over continue to grapple with issues of thermal discomfort both within and without – a condition that has arisen due to incessant urbanization, climate change, among others. The current study focussed on assessing the level of thermal stress both in and outdoors towards finding measures to reduce overheating in spaces within the Savannah climatic region of Ghana through a four-stage approach.Design/methodology/approachA four-stage approach has been used for the study; thus, a thermal comfort analysis based on physiologically equivalent temperature (PET), overheating assessment, a subjective thermal responses/evaluation of residents and a simulation effort to improve comfort.FindingsThere was an indication of “moderate cold stress to slight cold stress” on the coolest day (28th December). On the warmest day (12th April), however, the indoor environment had exceedance and severity of overheating of at least 56% and 38-degree hours. The acceptable comfort range and comfort temperatures of occupants of buildings in the study area have been determined to be 25.5–33 °C by the thermal sensation survey. Meanwhile, the simulation showed that a 200% increase in thermal mass, exterior wall insulation and roof extension and insulation has the potential to generate a reduction of 18% in overheated hours.Originality/valueThe paper unearths the flagrant disregard for thermal comfort in an attempt of “copying blindly” architecture from Southern Ghana by the affluent within the Savannah Region. Again, data provided prove that indeed human activities have worsened the plight of inhabitants through materials as well as construction methods.

Author(s):  
Lingjiang Huang ◽  
Jian Kang

AbstractThe solar incidence on an indoor environment and its occupants has significant impacts on indoor thermal comfort. It can bring favorable passive solar heating and can result in undesired overheating (even in winter). This problem becomes more critical for high altitudes with high intensity of solar irradiance, while received limited attention. In this study, we explored the specific overheating and rising thermal discomfort in winter in Lhasa as a typical location of a cold climate at high altitudes. First, we evaluated the thermal comfort incorporating solar radiation effect in winter by field measurements. Subsequently, we investigated local occupant adaptive responses (considering the impact of direct solar irradiance). This was followed by a simulation study of assessment of annual based thermal comfort and the effect on energy-saving potential by current solar adjustment. Finally, we discussed winter shading design for high altitudes for both solar shading and passive solar use at high altitudes, and evaluated thermal mass shading with solar louvers in terms of indoor environment control. The results reveal that considerable indoor overheating occurs during the whole winter season instead of summer in Lhasa, with over two-thirds of daytime beyond the comfort range. Further, various adaptive behaviors are adopted by occupants in response to overheating due to the solar radiation. Moreover, it is found that the energy-saving potential might be overestimated by 1.9 times with current window to wall ratio requirements in local design standards and building codes due to the thermal adaption by drawing curtains. The developed thermal mass shading is efficient in achieving an improved indoor thermal environment by reducing overheating time to an average of 62.2% during the winter and a corresponding increase of comfort time.


Urban Science ◽  
2021 ◽  
Vol 5 (3) ◽  
pp. 53
Author(s):  
Haven Hailu ◽  
Eshetu Gelan ◽  
Yared Girma

Indoor thermal comfort is an essential aspect of sustainable architecture and it is critical in maintaining a safe indoor environment. Expectations, acceptability, and preferences of traditional and modern buildings are different in terms of thermal comfort. This study, therefore, attempts to evaluate the indoor thermal comforts of modern and traditional buildings and identify the contributing factors that impede or facilitate indoor thermal comfort in Semera city, Ethiopia. This study employed subjective and objective measurements. The subjective measurement is based on the ASHRAE seven-point thermal sensation scale. An adaptive comfort model was employed according to the ASHRAE standard to evaluate indoor thermal comfort. The results revealed that with regards to thermal sensational votes between −1 and +1, 88% of the respondents are satisfied with the indoor environment in traditional houses, while in modern houses this figure is 22%. Likewise, 83% of occupants in traditional houses expressed a preference for their homes to remain the same or be only slightly cooler or warmer. Traditional houses were, on average, in compliance with the 80% acceptability band of the adaptive comfort standard. The study investigated that traditional building techniques and materials, in combination with consideration of microclimate, were found to play a significant role in regulating the indoor environment.


Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 808 ◽  
Author(s):  
Hao Tian ◽  
Wei Zhang ◽  
Lingzhi Xie ◽  
Zhichun Ni ◽  
Qingzhu Wei ◽  
...  

Thermal comfort is an important aspect to take into consideration for the indoor environment of a building integrated with a semi-transparent Photovoltaics (STPV) system. The thermal comfort of units with photovoltaic windows and that of conventional windows, which is an ordinary without PV, were evaluated via on-site tests and questionnaires. Using the thermal comfort investigation of the test rig, the maximum difference in air temperature was found to be around 5 °C between test unit and comparison unit. The predicted mean vote (PMV)–predicted percentage dissatisfied (PPD) value of the test unit was better than that of the comparison unit. It was observed that on sunny days, the PMV value ranged from 0.2 (nature) to 1.3 (slightly warm) in the test unit, and that of the comparison unit was 0.7 (slightly warm) to 2.0 (warm), thereby providing better thermal comfort, especially during mornings. The maximum difference in PPD values was found to reach 27% between the two units at noon. On cloudy days, the difference was negligible, and the thermal sensation between the foot and the head were almost the same. Fifty respondents were asked to complete a carefully designed questionnaire. The thermal sensation of the test unit was better than that of comparison unit, which corresponded with the test results. Thermal, lighting, acoustic, and other environment comfort scores were combined, and the acceptance of the test unit with the STPV windows was found to be 73.8%. The thermal sensation difference between men and women was around 5%. Thus, during summer, STPV windows can improve the thermal comfort and potentially reduce the air-conditioning load.


2019 ◽  
Vol 282 ◽  
pp. 02031
Author(s):  
Ricardo M.S.F. Almeida ◽  
Eva Barreira ◽  
Sandra Soares ◽  
Ramos Nuno M.M. ◽  
Sérgio Lopes ◽  
...  

The importance of a good indoor environment for peoples’ health and wellbeing is nowadays clearly established. Besides enhancing the wellbeing of building occupants and helping decrease the occurrence of building related illness, a good indoor environment can also lead to a decrease in worker complaints and absenteeism. This paper presents the results of a three-month monitoring campaign where the thermal comfort of a toll station was evaluated, including the main room and the cabins. The physical parameters required for the assessment of both global and local thermal comfort were measured and the results were compared with the thermal perception of the occupants, which was collected through questionnaires. The indoor environmental quality in the main room was better than in the cabins and a mismatch between the PMV index and the occupants thermal sensation was identified.


2016 ◽  
Vol 34 (4/5) ◽  
pp. 427-445 ◽  
Author(s):  
Baharuddin Hamzah ◽  
Muhammad Taufik Ishak ◽  
Syarif Beddu ◽  
Mohammad Yoenus Osman

Purpose The purpose of this paper is to analyse thermal comfort and the thermal environment in naturally ventilated classrooms. Specifically, the aims of the study were to identify the thermal environment and thermal comfort of respondents in naturally ventilated university classrooms and compare them with the ASHRAE and Indonesian National Standard (SNI); to check on whether the predicted mean vote (PMV) model is applicable or not for predicting the thermal comfort of occupants in naturally ventilated university classrooms; and to analyse the neutral temperature of occupants in the naturally ventilated university classrooms. Design/methodology/approach The study was carried out at the new campus of Faculty of Engineering, Hasanuddin University, Gowa campus. A number of field surveys, which measured thermal environments, namely, air temperature, mean radiant temperature (MRT), relative humidity, and air velocity, were carried out. The personal activity and clothing properties were also recorded. At the same time, respondents were asked to fill a questionnaire to obtain their thermal sensation votes (TSV) and thermal comfort votes (TCV), thermal preference, and thermal acceptance. A total of 118 respondents participated in the study. Before the survey was conducted, a brief explanation was provided to the participants to ensure that they understood the study objectives and also how to fill in the questionnaires. Findings The results indicated that the surveyed classrooms had higher thermal environments than those specified in the well-known ASHRAE standard and Indonesian National Standard (SNI). However, this condition did not make respondents feel uncomfortable because a large proportion of respondents voted within the comfort zone (+1, 0, and −1). The predictive mean vote using the PMV model was higher than the respondents’ votes either by TSV or by TCV. There was a huge difference between neutral temperature using operative temperature (To) and air temperature (Ta). This difference may have been because of the small value of MRT recorded in the measured classrooms. Originality/value The research shows that the use of the PMV model in predicting thermal comfort in the tropic region might be misleading. This is because PMV mostly overestimates the TSV and TCV of the respondents. People in the tropic region are more tolerant to a higher temperature. On the basis of this finding, there is a need to develop a new thermal comfort model for university classrooms that is particularly optimal for this tropical area.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Zul-Atfi Bin Ismail

PurposeImproper evaluation and information mismanagement concerning thermal comfort appears to negatively affect occupants' satisfaction and building energy consumption in precast concrete (PC) building contexts. Predictive models are particularly problematic in PC building construction projects where natural ventilation levels do not coincide with occupants' thermal comfort and thermal sensation specifications.Design/methodology/approachA systematic literature review is undertaken to explore the viability and benefits of a new ICT-based approach for meeting social and environmental objectives.FindingsSophisticated thermal comfort system solutions are essential for optimising thermal comfort and saving energy in PC building construction projects.Originality/valueIt is imperative that designers and manufacturers are kept up-to-date with the possibilities and potentials associated with new and nascent technologies so that building projects can meet key sustainability criteria.


2018 ◽  
Vol 30 (4) ◽  
pp. 462-476 ◽  
Author(s):  
Krittiya Ongwuttiwat ◽  
Sudaporn Sudprasert ◽  
Thananchai Leephakpreeda

Purpose The purpose of this paper is to present the determination of human thermal comfort with wearing clothes, with different water vapor permeability. Currently, the predicted mean vote (PMV) equation is widely used to determine thermal sensation scales of human comfort. However, moisture permeability of clothes has been not taken in account where the heat is lost from a human body due to water vapor diffusion through clothes. Design/methodology/approach In this study, the heat loss is derived based on the real structure of textiles, causing water vapor pressure difference between air on skin and ambient air. The PMV equation is modified to differentiate a thermal sensation scale of comfort although patterns of clothes are the same. Interview tests are investigated with wearing clothes from three types of textiles: knitted polyester, coated nylon–spandex, and polyurethane, under various air conditions. Findings The moisture permeabilities of knitted polyester, coated nylon–spandex and polyurethane are 16.57×10−9 kg/m2 s•kPa, 9.15×10−9 kg/m2•s•kPa and 2.99×10−9 kg/m2•s•kPa, respectively. The interviews reveal that most people wearing knitted-polyester clothes have the greatest cold sensations under various air conditions since moisture permeability is the highest, compared to coated nylon–spandex, and polyurethane leather. Correspondingly, the predicted results of the modified PMV equation are close to the actual mean votes of interviewees with a coefficient of determination R2=0.83. On the other hand, the coefficient of determination from the predicted results of the conventional PMV equation is significantly lower than unity, with R2=0.42. Practical implications In practice, this quantitative determination on human thermal comfort gives some concrete recommendations on textile selection of clothes for acceptable satisfaction of thermal comfort under various surrounding conditions of usage. Originality/value The modified PMV equation effectively determines human comfort on a thermal sensation scale due to the moisture permeability of clothes. To make generic conclusion, experimental results of additional three textiles, such as plain weave/lining polyester, knitted spandex, and open structure polyester, are reported. They confirm that the modified PMV equation effectively determines human comfort on a thermal sensation scale due to the moisture permeability of clothes.


2011 ◽  
Vol 224 ◽  
pp. 115-119 ◽  
Author(s):  
Ismail Muhammad Azzam ◽  
Abdul Rashid Fahanim

Achieving thermal comfort in the tropical climate of Malaysia is always a great challenge for any house designer or builder. Although some practical solutions have been developed over centuries through the slow but constant evolution of indigenous houses such the Malay house, the longhouses in Borneo and the Chinese townhouses in Melaka, their integration into contemporary designs have been hampered by various modern constraints. For instance, building the Malay house in urban areas is deemed unsuitable due to the need for wide land lots and their perceptively fragile building materials that do not allay any security worries. The lack of skilled carpenters for building such a house is also a worsening problem. Hence, new and innovative strategies to achieve thermal comfort for contemporary houses are greatly needed to serve the needs and expectations of an urbanized society. One method that has been studied and proved successful is the Smart and Cool Home system which was first used at a private bungalow in Semenyih, Malaysia. The overarching principle of this system is to reverse the role of the building envelope from being a thermal mass into a heat sink which effectively reduces heat gains and allow the occupants inside to easily adapt to a milder indoor environment. This paper describes this house in detail and provides some understanding of the principles involved.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Nurul Hayati Yong ◽  
Qi Jie Kwong ◽  
Kok Seng Ong ◽  
Dejan Mumovic

Purpose As suggested in many previous studies, good thermal comfort and indoor air quality (IAQ) played a significant role in ensuring human comfort, health and productivity in buildings. Hence, this study aims to evaluate the thermal comfort and IAQ conditions of open-plan office areas within a green-certified campus building through a post occupancy evaluation. Design/methodology/approach Using the field measurement method, environmental dataloggers were positioned at three office areas during office hours to measure the levels of thermal comfort parameters, CO2 concentrations and the supply air rates. At the same time, questionnaires were distributed to the available office staff to obtain their perception of the indoor environment. The findings were then compared with the recommended environmental comfort ranges and used to calculate the thermal comfort indices. Findings Results show that the physical parameters were generally within acceptable ranges of a local guideline. The neutral temperature based on the actual mean vote at these areas was 23.9°C, which is slightly lower than the predicted thermal neutrality of 25.2°C. From the surveyed findings, about 81% of the occupants found their thermal environment comfortable with high adaptation rates. A preference for cooler environments was found among the workers. Meanwhile, the air quality was perceived to be clean by a majority of the respondents, and the mean ventilation rate per person was identified to be sufficient. Research limitations/implications This study focussed on the thermal environment and air quality at selected office spaces only. More work should be carried out in other regularly occupied workplaces and study areas of the green educational building to allow a more thorough analysis of the indoor air conditions. Practical implications This paper highlights on the thermal comfort and air quality conditions of the air-conditioned office spaces in a green-certified campus building and is intended to assist the building services engineers in effective air conditioning control. The findings reported are useful for thermal comfort, IAQ and subsequently energy efficiency improvements in such building type where adjustments on the air temperature set-point can be considered according to the actual requirements. This study will be extended to other green campus spaces for a more exhaustive analysis of the indoor environment. Originality/value There is limited information pertaining to the environmental comfort levels in offices of green campus in the tropics. This study is, therefore, one of the earliest attempts to directly explore the thermal comfort and IAQ conditions in such workplace using both on-site physical measurement and questionnaire survey.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Chuloh Jung ◽  
Jihad Awad ◽  
Naglaa Sami Abdelaziz Mahmoud ◽  
Muna Salameh

Purpose This study aims to evaluate The Springs’ indoor environment, one of the iconic townhouse-type residential buildings in Dubai, more efficiently for the integrated evaluation of the indoor environment with the weights of indoor environmental factors such as thermal, indoor air, lighting and acoustic. Design/methodology/approach The weights of the indoor environment factors were derived for the integrated evaluation to reflect the residents’ preferences. Based on the post-occupancy evaluation (P.O.E.) survey, the weights according to the gender, age group and indoor spaces followed a comparison and analytical processes. Findings This paper had found the priority of residents’ needs for each space in The Springs project. In summer, thermal comfort was the most important factor for living room and the master bedroom. In winter, the priority for living room and kitchen was the indoor air quality. Research limitations/implications As it is the first research survey for housing project in Dubai, it needs to be extended to other housing projects in Dubai. To increase the reliability of the weights calculated through this study and the applicability of the integrated indoor environmental evaluation, more in-depth P.O.E. survey is needed with wide range of survey participants. Social implications This paper will help developing guidelines for future renovation based on the comparative analysis among thermal comfort, acoustic comfort, lighting comfort and indoor air comfort. Originality/value This paper is the first attempt to analyze the condition of early housing projects in Dubai. The data can be used to increase not only the design quality and marketability of housing projects in Dubai but also the condition of residents’ health status to avoid sick building syndrome from approximately 20 years old buildings.


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