Inter-personal factors affecting building occupants’ thermal tolerance at cold outdoor condition during an autumn–winter period

2019 ◽  
Vol 29 (7) ◽  
pp. 987-1005 ◽  
Author(s):  
Shahla Ghaffari Jabbari ◽  
Aida Maleki ◽  
Mohammad Ali Kaynezhad ◽  
Bjarne W. Olesen

The study was conducted to investigate thermal adaptation and the impact of individual differences on developing thermal tolerance when the outdoor temperature falls below 10°C. The applicability of the predicted mean vote (PMV) model was investigated, too. The concept of occupant’s ‘Temperament’ was evaluated as a psychological-adaptation factor. Two main hypotheses were: (a) people with different temperaments would experience different thermal sensations and (b) the classic PMV- predicted percentage dissatisfied (PPD) model is capable of predicting the neutral sensation in heated buildings under cold outdoor temperatures. There was a direct relationship between individual temperament and clothing level as well as thermal sensation. The occupants who were assessed to have cold temperament tend to wear thicker clothes and were more sensitive to variations in indoor air temperature than others. Females with a cold temperament were more than twice as likely to be affected by indoor air temperature as those with a warm temperament. The PMV-PPD model was able to predict the mean neutral temperature in the heated buildings even when the outdoor temperature fell below 10°C. However, when occupants were able to control high indoor temperature, the percentage of true prediction of actual mean votes by the adaptive thermal heat balance model was more than that by the classic PMV model.

2021 ◽  
Vol 13 (4) ◽  
pp. 640
Author(s):  
Sadroddin Alavipanah ◽  
Dagmar Haase ◽  
Mohsen Makki ◽  
Mir Muhammad Nizamani ◽  
Salman Qureshi

The changing climate has introduced new and unique challenges and threats to humans and their environment. Urban dwellers in particular have suffered from increased levels of heat stress, and the situation is predicted to continue to worsen in the future. Attention toward urban climate change adaptation has increased more than ever before, but previous studies have focused on indoor and outdoor temperature patterns separately. The objective of this research is to assess the indoor and outdoor temperature patterns of different urban settlements. Remote sensing data, together with air temperature data collected with temperature data loggers, were used to analyze land surface temperature (outdoor temperature) and air temperature (indoor temperature). A hot and cold spot analysis was performed to identify the statistically significant clusters of high and low temperature data. The results showed a distinct temperature pattern across different residential units. Districts with dense urban settlements show a warmer outdoor temperature than do more sparsely developed districts. Dense urban settlements show cooler indoor temperatures during the day and night, while newly built districts show cooler outdoor temperatures during the warm season. Understanding indoor and outdoor temperature patterns simultaneously could help to better identify districts that are vulnerable to heat stress in each city. Recognizing vulnerable districts could minimize the impact of heat stress on inhabitants.


2016 ◽  
Vol 16 (1) ◽  
pp. 7-20 ◽  
Author(s):  
Renata De Vecchi ◽  
Christhina Maria Cândido ◽  
Roberto Lamberts

Abstract Currently, there is a rising trend for commercial buildings to use air conditioning to provide indoor thermal comfort. This paper focuses on the impact of prolonged exposure to indoor air-conditioned environments on occupants' thermal acceptability and preferences in a mixed-mode building in Brazil. Questionnaires were administered while indoor microclimatic measurements were carried out (i.e., air temperature, radiant air temperature, air speed and humidity). Results suggest significant differences in occupants' thermal acceptability and cooling preferences based on thermal history; differences were found between groups based on different physical characteristics (i.e., different gender and body condition). The findings also indicated a significant potential to implement temperature fluctuations indoors when occupants are exposed to air conditioning environments in warm and humid climates.


Technologies ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 90
Author(s):  
Siliang Lu ◽  
Erica Cochran Hameen

Heating, ventilation and air-conditioning (HVAC) systems play a key role in shaping office environments. However, open-plan office buildings nowadays are also faced with problems like unnecessary energy waste and an unsatisfactory shared indoor thermal environment. Therefore, it is significant to develop a new paradigm of an HVAC system framework so that everyone could work under their preferred thermal environment and the system can achieve higher energy efficiency such as task ambient conditioning system (TAC). However, current task conditioning systems are not responsive to personal thermal comfort dynamically. Hence, this research aims to develop a dynamic task conditioning system featuring personal thermal comfort models with machine learning and the wireless non-intrusive sensing system. In order to evaluate the proposed task conditioning system performance, a field study was conducted in a shared office space in Shanghai from July to August. As a result, personal thermal comfort models with indoor air temperature, relative humidity and cheek (side face) skin temperature have better performances than baseline models with indoor air temperature only. Moreover, compared to personal thermal satisfaction predictions, 90% of subjects have better performances in thermal sensation predictions. Therefore, personal thermal comfort models could be further implemented into the task conditioning control of TAC systems.


2020 ◽  
Vol 172 ◽  
pp. 05004
Author(s):  
Raimo Simson ◽  
Taaniel Rebane ◽  
Martin Kiil ◽  
Martin Thalfeldt ◽  
Jarek Kurnitski

In this study we analysed the climatic conditions for infiltration estimation, different calculation methods and infiltration impact on heat load for heating systems dimensioning. To determine the wind conditions at low air temperatures of the coastal- and inland climatic zones in Estonia, 42 years of climatic data for Tallinn and Tartu were investigated. Calculation models with detailed air leakages were constructed of a single and two-storey detached house using dynamic simulation software IDA ICE. Simulations were carried out with the constructed calculation models, simulating various wind and sheltering conditions to determine the heating load of the buildings under measured wind conditions at the design external air temperatures. The simulation results were compared with results calculated with European Standard EN 12831:2017, methodology given in the Estonian regulation for calculating energy performance of buildings and with simulations using the default settings in IDA ICE based on the ASHRAE design day conditions. The percentage of heat losses caused by infiltration was found as 13-16% of all heat losses for the studied buildings. Simulations with historical climate periods showed that even in windy weather conditions the heating system dimensioned by the methods analysed may not be able to provide the required indoor air temperature. Analysis using the coldest and windiest periods showed that when systems are dimensioned by the studied methods, the highest decline in indoor air temperature occurs on the windiest day and not on the coldest day. The impact of high wind speeds and low sheltering conditions resulted up to 50% of all heat losses.


2020 ◽  
Vol 12 (22) ◽  
pp. 9672
Author(s):  
Mamdooh Alwetaishi ◽  
Ashraf Balabel ◽  
Ahmed Abdelhafiz ◽  
Usama Issa ◽  
Ibrahim Sharaky ◽  
...  

The study investigated the level of thermal comfort in historical buildings located at a relatively high altitude in the Arabian Desert of Saudi Arabia. The study focused on the impact of the use of thermal mass and orientation on the level of thermal performance at Shubra and Boqri Palaces. Qualitative and quantitative analyses were used in this study, including a questionnaire interview with architecture experts living at the relatively high altitude of Taif city, to obtain data and information from local experts. The computer software TAS EDSL was used along with on-site equipment, such as thermal imaging cameras and data loggers, to observe the physical conditions of the building in terms of its thermal performance. The study revealed that the experts’ age and years of experience were important aspects while collecting data from them during the survey. The use of thermal mass had a slight impact on the indoor air temperature as well as the energy consumption, but it helped in providing thermal comfort. Use of ventilation can improve thermal comfort level. Evaporative cooling technique has a considerable impact on reducing indoor air temperature with 4 °C drop, improving the thermal comfort sensation level. The novelty of this work is that, it links the outcomes of qualitative results of experts with field monitoring as well as computer modelling. This can contribute as method to accurately collect data in similar case studies.


2021 ◽  
Vol 246 ◽  
pp. 15003
Author(s):  
Natalia Krawczyk

Nowadays, we spend most of our time inside buildings. Thus, ensuring adequate thermal comfort is an important issue. The paper discusses the issue of thermal comfort assessment in the intelligent low energy building “Energis” of Kielce University of Technology (Poland). The tests conducted in a selected lecture theater focused on collecting anonymous questionnaires containing thermal sensation and air quality votes of the respondents as well as performing measurements of indoor air parameters (air and globe temperatures, relative humidity, air velocity and CO2 concentration). Based on the obtained data a comparison has been done between the actual sensation votes of the volunteers and the calculation results performed with the Fanger thermal comfort model. Two indices have been considered in the paper: PMV (Predicted Mean Vote) and PPD (Predicted Percentage Dissatisfied). A modification of the model has also been proposed, which considers the impact of the carbon dioxide concentration on thermal comfort.


2013 ◽  
Vol 805-806 ◽  
pp. 1620-1624 ◽  
Author(s):  
Wan Ying Qu

A thermal comfort field study was investigated in residential buildings of cold regions in transition season during which the indoor thermal environment conditions are measured, the thermal sensation value of the occupants is questioned and recorded. A seven-point thermal sensation scale was used to evaluate the thermal sensation. The statistical method was used to analyze the data and the conclusions are as follows in transition season: clothing increase in 0.1clo when the indoor air temperature is lowered by 1°C; and clothing will be a corresponding increase in 0.06clo when the outdoor air temperature is lowered by 1°C; clothing also varies with gender, age, weight and thermal history and other related; the measured thermal neutral temperature is 21.3°C; and the minimum accepted temperature is 11.4 °C in transition season in cold regions. Most people choose to change clothes, switch and other passive measures, and occasionally take active measures of heater, electric fans and others.


Author(s):  
Halina Dzieżyc ◽  
Kazimierz Chmura ◽  
Maciej Piotrowski

Abstract Influence of meteorological conditions on the yield of winter oilseed rape in Lower Silesia. This work uses the results of Post-registration Cultivar and Agricultural Experimentation conducted in 1999-2011 in Lower Silesia, on soils of very good and good wheat complex. The rape vegetation season was divided into five periods that approximately corresponded to the phenological phases of the plant, namely: September-November (from sowing to stemming the growing season in the autumn), December-March (stunted vegetation - renewal of vegetation), April (renewal of vegetation - the beginning of flowering), May (flowering), June (end of flowering - technical maturity). In the constructed regression model the following factors were included: the average air temperature and total precipitation in the periods, the content of phosphorus, potassium and pH of soil and fertilization with nitrogen, phosphorus and potassium. Comparing the impact of meteorological conditions in different growing periods of winter rape, it was found that the weakest impact on the yield had temperature and precipitation from September to November. During this period, the optimum for yield are the following conditions: average temperature 10.4°C and precipitation total 145 mm. The winter period (December- March) has the strongest impact on the yield of rape. The yield is conspicuously higher with lower average air temperatures. Optimal for yield is precipitation of 171 mm (highest tested) and a relatively low average air temperature (-0.9°C). In April, the decisive factor is rainfall. Its lower values (12 mm) favour higher yield. The optimum weather in this period is 12 mm precipitation and average temperature of 9.1°C. Rape yield increases with increasing average air temperature in May and is highest when its value is 15°C and rainfall in this month is above average (73 mm). The weather in June has less impact on rape crop than in the three previous periods. The optimal layout is: 27 mm precipitation and temperature 16°C, these values being the smallest tested


2011 ◽  
Vol 2 (1) ◽  
pp. 12-17 ◽  
Author(s):  
Azhaili Baharun ◽  
Siti Halipah Ibrahim ◽  
Mohammad Omar Abdullah ◽  
Ooi Koon Beng

EnergyPlus® simulated indoor temperatures of a single storey building at the east campus of Universiti Malaysia Sarawak, for April and June, are validated with measurements taken in 2007.The measured local outdoor temperature was used together with the global solar radiation, wind velocity, relative humidity and cloud cover measured at the Kuching airport to replace the typical meteorological year (TMY) values in the EnergyPlus® weather (EPW) file to fonn a Modified EPW weather file at the time/date of experiments. The remaining fields of the Modified EPW contain TMY data including the direct and diffuse solar radiations and the 'sky's' infrared radiation, which is also present at night.Analysis of the temperatures at the windows simulated with the EPW and Modified EPW weather files for the April and June experiments show the strong influence of the outdoor temperature and importance of the global solar radiation in the weather file and local outdoor temperature is used in the Modified EPW.Day time peak mismatches between the measured indoor air temperature and the indoor air temperature simulated with the Modified EPW is 2 to 3 deg C. These are due to the use of the TMY direct and diffuse solar radiations in the heat balance algorithms at the outside surfaces. The corresponding night time mismatches are less than 1 deg C because the TMY values of the long wave infra-red radiation emitted from molecules and particles in the atmosphere in the Modified EPW are used in simulation.


2020 ◽  
Vol 172 ◽  
pp. 15009
Author(s):  
Pengcheng Shi ◽  
Yonghui Li ◽  
Yuan Ying ◽  
Shuichi Hokoi

Bathing is a typical daily behavior among Chinese elderly people, which causes large thermal environmental fluctuations especially in winter. Rapid fluctuations of the thermal environment can lead to a drastic change in human blood pressure and may cause accidents while bathing. The most common style of Chinese bathing is showers. Information on the thermal environment during bathing is limited, making analysis difficult. This study aims to understand the current situation of bathing in old residences in Nanjing, China. To examine elderly bathing behaviors and thermal environments in bathrooms during bathing, we monitored the thermal environment in three elderly families and administered a questionnaire survey from which 49 responses were obtained. Results were categorized into environmental and personal factors that affect blood pressure during bathing. In winter, the temperature in a bathroom is often below 10℃. A heating device is installed close to the head (87%); thus, the thermal environment is vertically non-uniform (air temperature difference often exceeds 10℃). Most elderly individuals bathe for less than 30 minutes and the rise in air temperature often exceeds 10℃. This information will be used as the boundary conditions for thermo-physiological models that can quantitatively assess the impact of the environment on the elderly, and for the renovation of bathrooms.


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