Assessment of Urban Thermal Field Variance Index and Thermal Comfort Level of Addis Ababa Metropolitan City, Ethiopia

2021 ◽  
Author(s):  
Mitiku Badasa Moisa ◽  
Dessalegn Obsi Gemeda
Keyword(s):  
Thermal Comfort ◽  
Thermal Field ◽  
Addis Ababa ◽  
Comfort Level ◽  
Metropolitan City ◽  
Variance Index

scholarly journals Análise das Condições do Campo Térmico em Ambiente Urbano: Estudo de Caso em Campus Universitário (Analysis of Conditions of Thermal Comfort in Urban Environment: a Case Study in University Campus)

2011 ◽  
Vol 4 (2) ◽  
pp. 336
Author(s):  
Joel Silva dos Santos ◽  
Vicente De Paulo R. da Silva ◽  
Lincoln Eloi de Araújo ◽  
Eduardo Rodrigues Viana de Lima ◽  
Angelina Dias Leão Costa
Keyword(s):  
Thermal Comfort ◽  
Urban Environment ◽  
Thermal Field ◽  
Urban Climate ◽  
Ground Cover ◽  
Comfort Level ◽  
University Campus ◽  
High Concentration ◽  
Data Logger

O estudo do clima urbano, especificamente do comportamento do seu campo térmico, constitui-se em um dos grandes problemas socioambientais para as populações residentes nessas áreas. Dessa forma, o presente trabalho analisa os efeitos dos diferentes tipos de cobertura de solo nas condições do campo térmico do Campus I da Universidade Federal da Paraíba, localizado na cidade de João Pessoa, PB. As medições da temperatura do ar e umidade relativa foram realizadas em dois períodos distintos (seco e chuvoso), utilizando-se data logger Hobos em seis pontos representativos da área de estudo. O Índice de Thom foi utilizado para analisar o nível de conforto térmico nas escalas diária e horária e o tipo de cobertura de solo de cada ponto analisado foi definido considerando oito classes, de acordo com a percentagem de vegetação e de materiais permeáveis e impermeáveis existentes no entorno do ponto. Os resultados do trabalho permitiram caracterizar o micro clima local e identificar alterações no ambiente provocadas pelo adensamento de construções, além de fornecerem dados para fazer sugestões no sentido de minimizar esses efeitos através da manutenção da arborização remanescente da Mata Atlântica. As análises quantitativas e qualitativas dos dados revelaram diferentes condições micro climáticas na área de estudo que foram modificadas substancialmente em função da cobertura do solo. As áreas com alta concentração de materiais impermeáveis mostraram nível de desconforto térmico bastante elevado no período de maior demanda atmosférica, que ocorre entre 11 e 15h. Palavras-chave: Clima urbano, Campo térmico, Índice de Desconforto de Thom   Analysis of Conditions of Thermal Comfort in Urban Environment: a Case Study in University Campus  ABSTRACT The study of urban climate, specifically the behavior of their thermal field, it constitutes one of the great social and environmental problems for people living in these areas. In this way, the present study analyzes the effects of different types of ground cover in the thermal field of the Federal University of Paraíba, Campus I which is located in the city of João Pessoa, PB. The measurements of air temperature and relative humidity were carried out in two distinct periods (dry and wet seasons), using data logger Hobos in 6 representative points through study area. Thom’s discomfort index was used to analyze the thermal comfort level in daily values into one-hour time scale through University campus. The types of ground cover for each analyzed point were classified into 8 classes according to percentage cover in vegetation and permeable and impermeable materials. The results allowed to characterize the local microclimate, as well as identify environment changes provided by urban crowding, and to suggest actions to reduction of these effects by maintaining Atlantic forest biodiversity. The quantitative and qualitative data analysis showed that the different microclimatic conditions at experimental area were substantially due to soil cover changes. The areas with high concentration level in waterproof materials showed high level of thermal discomfort just in the period with highest atmospheric demand which it occurs from 11 to 15h.   Keywords: Urban climate, thermal comfort, Thom’s index

scholarly journals Measurement of Thermal Comfort in Urban Public Spaces Semarang, Indonesia

2021 ◽  
Vol 29 (3) ◽  
Author(s):  
Rina Kurniati ◽  
Wakhidah Kurniawati ◽  
Diah Intan Kusumo Dewi ◽  
Mega Febrina Kusumo Astuti
Keyword(s):  
Thermal Comfort ◽  
Climate Model ◽  
Environmental Changes ◽  
Measurement Data ◽  
Public Spaces ◽  
Comfort Level ◽  
Design Elements ◽  
Central Java ◽  
Outdoor Environments ◽  
Road Geometry

Indonesia reported a maximum annual temperature rise of 0.3°C in urban regions. Semarang, the largest metropolitan city in the province of Central Java, is also experiencing an increase in temperature due to climate change therefore activities in urban public spaces are disrupted due to the absence of a comfortable temperature. Urban design elements, including land cover materials, road geometry, vegetation and traffic frequency expressed significant effects on micro-climate. Measurement of Thermal Comfort in Urban Public Spaces Semarang was carried out s at the micro level as an old historical district The Old Town and Chinatown. This increment indeed influences thermal comfort level in its outdoor environments which are important for comfortability of outdoor activity. This study aims to analyse surface temperature through Thermal Comfort Measurement. Data was obtained by measuring air temperature, wind speed and humidity in the morning, afternoon, and evening. Inverse distance weighted (IDW), thermal comfort calculations and micro-climate model were employed to evaluate existing physical conditions of these settlements. The results showed both Old Town and Chinatown observed thermal comfort value above 27°C and are categorized as uncomfortable for outdoor activities. This research is contributing to the need to further develop public spaces to potentially adapt to environmental changes.

scholarly journals Prediction human skin temperature in comfort level

2019 ◽  
Vol 1 (3) ◽  
pp. 1-4
Author(s):  
Zaina Norhallis Zainol ◽  
Masine Md. Tap ◽  
Haslinda Mohamed Kamar
Keyword(s):  
Thermal Comfort ◽  
Skin Temperature ◽  
Human Skin ◽  
Blood Perfusion ◽  
Comfort Level ◽  
Working Environment ◽  
Percentage Error ◽  
Bioheat Equation ◽  
Acceptable Error ◽  
Human Arm

Thermal comfort is the human subject perceive satisfaction to the work environment. The thermal comfort need to be achieve towards productive working environment. The comfort level of the subject is affected by the human skin temperature. To assess the skin temperature with the sorrounding by conducting human experiment in the climatic chamber. It is rigorous and complex experiment.This study was developed to predict human skin temperature in comfort level with the finite element method and the bioheat equation. The bioheat equation is a consideration of metabolic heat generation and the blood perfusion to solve heat transfer of the living tissue. It is to determine the skin temperature focussing at the human arm. From the study, it is found that the predicted skin temperature value were in well agreement with the experimental results. The percentage error insignificant with acceptable error of 1.05%.

scholarly journals Determination of Optimum Envelope of Religious Buildings in Terms of Thermal Comfort and Energy Consumption: Mosque Cases

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6597
Author(s):  
Ahmet Bircan Atmaca ◽  
Gülay Zorer Gedik ◽  
Andreas Wagner
Keyword(s):  
Thermal Properties ◽  
Energy Consumption ◽  
Thermal Comfort ◽  
Thermal Insulation ◽  
Energy Savings ◽  
Gain Factor ◽  
Building Envelope ◽  
Comfort Level ◽  
Humid Climate ◽  
Savings Rate

Mosques are quite different from other building types in terms of occupant type and usage schedule. For this reason, they should be evaluated differently from other building types in terms of thermal comfort and energy consumption. It is difficult and probably not even necessary to create homogeneous thermal comfort in mosques’ entire usage area, which has large volumes and various areas for different activities. Nevertheless, energy consumption should be at a minimum level. In order to ensure that mosques are minimally affected by outdoor climatic changes, the improvement of the properties of the building envelope should have the highest priority. These optimal properties of the building envelope have to be in line with thermal comfort in mosques. The proposed method will be a guide for designers and occupants in the design process of new mosques or the use of existing mosques. The effect of the thermal properties of the building envelope on energy consumption was investigated to ensure optimum energy consumption together with an acceptable thermal comfort level. For this purpose, a parametric simulation study of the mosques was conducted by varying optical and thermal properties of the building envelope for a temperature humid climate zone. The simulation results were analyzed and evaluated according to current standards, and an appropriate envelope was determined. The results show that thermal insulation improvements in the roof dome of buildings with a large volume contributed more to energy savings than in walls and foundations. The use of double or triple glazing in transparent areas is an issue that should be considered together with the solar energy gain factor. Additionally, an increasing thickness of thermal insulation in the building envelope contributed positively to energy savings. However, the energy savings rate decreased after a certain thickness. The proposed building envelope achieved a 33% energy savings compared to the base scenario.

scholarly journals Sensitivity Analysis of Occupant Preferences on Energy Usage in Residential Buildings

2021 ◽  
Author(s):  
Kaleb Pattawi ◽  
Prateek Munankarmi ◽  
Michael Blonsky ◽  
Jeff Maguire ◽  
Sivasathya Pradha Balamurugan ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Thermal Comfort ◽  
Residential Buildings ◽  
Electricity Consumption ◽  
Cost Savings ◽  
The United States ◽  
Comfort Level ◽  
Electrical Grid ◽  
Home Energy Management ◽  
The Impact

Abstract Residential buildings, accounting for 37% of the total electricity consumption in the United States, are suitable for demand response (DR) programs to support effective and economical operation of the power system. A home energy management system (HEMS) enables residential buildings to participate in such programs, but it is also important for HEMS to account for occupant preferences to ensure occupant satisfaction. For example, people who prefer a higher thermal comfort level are likely to consume more energy. In this study, we used foresee™, a HEMS developed by the National Renewable Energy Lab (NREL), to perform a sensitivity analysis of occupant preferences with the following objectives: minimize utility cost, minimize carbon footprint, and maximize thermal comfort. To incorporate the preferences into the HEMS, the SMARTER method was used to derive a set of weighting factors for each objective. We performed week-long building energy simulations using a model of a home in Fort Collins, Colorado, where there is mandatory time-of-use electricity rate structure. The foresee™ HEMS was used to control the home with six different sets of occupant preferences. The study shows that occupant preferences can have a significant impact on energy consumption and is important to consider when modeling residential buildings. Results show that the HEMS could achieve energy reduction ranging from 3% to 21%, cost savings ranging from 5% to 24%, and carbon emission reduction ranging from 3% to 21%, while also maintaining a low thermal discomfort level ranging from 0.78 K-hour to 6.47 K-hour in a one-week period during winter. These outcomes quantify the impact of varying occupant preferences and will be useful in controlling the electrical grid and developing HEMS solutions.

A dynamic model for human thermal comfort for smart building applications

2019 ◽  
Vol 234 (4) ◽  
pp. 472-483
Author(s):  
Ghezlane Halhoul Merabet ◽  
Mohamed Essaaidi ◽  
Driss Benhaddou
Keyword(s):  
Thermal Comfort ◽  
Air Conditioning ◽  
Research Work ◽  
Comfort Level ◽  
Indoor Environments ◽  
Air Conditioning System ◽  
Human Thermal Comfort ◽  
Local Quality ◽  
Set Up ◽  
Air Conditioning Systems

Thermal comfort is closely related to the evaluation of heating, ventilation, and air conditioning systems. It can be seen as the result of the perception of the occupants of a given environment, and it is the product of the interaction of a number of personal and environmental factors. Otherwise, comfort issues still do not play an important role in the daily operation of commercial buildings. However, in the workplace, local quality effects, in addition to the health, the productivity that has a significant impact on the performance of the activities. In this regard, researchers have conducted, for decades, investigations related to thermal comfort and indoor environments, which includes developing models and indices through experimentations to establish standards to evaluate comfort and factors and set-up parameters for heating, ventilation, and air conditioning systems. However, to our best knowledge, most of the research work reported in the literature deals only with parameters that are not dynamically tracked. This work aims to propose a prototype for comfort measuring through a wireless sensor network and then presenting a model for thermal comfort prediction. The developed model can be used to set up a heating, ventilation, and air conditioning system to meet the expected comfort level. In particular, the obtained results show that there is a strong correlation between users’ comfort and variables such as age, gender, and body mass index as a function of height and weight.

Thermal Performance of Nepalese Building- A Case Study of Dhulikhel and Biratnagar

2020 ◽  
Vol 15 (3) ◽  
pp. 73-77
Author(s):  
Nischal Chaulagain ◽  
Bivek Baral ◽  
Saurav Raj Bista
Keyword(s):  
Thermal Comfort ◽  
Thermal Performance ◽  
Research Work ◽  
Building Design ◽  
Comfort Level ◽  
Indoor Climate ◽  
Design Code ◽  
Electric Equipment ◽  
The Government ◽  
Real Scenario

Nepal has wide variation in altitude, so does its climate, lifestyle and housing. The building design code issued by the Government of Nepal does not address the issue of thermal comfort, which could be the reason the modern buildings built under the design code are performing poorly in terms of indoor thermal comfort. As a result, people have largely compromised in accommodation. The research includes selection of two representative buildings (at Biratnagar and Dhulikhel) followed by real time monitoring of indoor climate (temperature and Relative humidity). The logged data was used to calibrate the computer model. The model was approximated to real scenario including indoor heat loads from people, lighting, electric equipment and infiltration. Building energy modeling was done in EnergyPlus. The research work depicts the thermal performance of building by comparing the indoor climate of selected buildings of Biratnagar and Dhulikhel with the ASHARE suggested thermal comfort level for humans. The major problem found in the buildings of Biratnagar was overheating for more than 6 months period while for Dhulikhel was under heating for more than 4 months period. The author suggests further research to analyze passive techniques to improve thermal performance and reduce active energy consumption.

An enthalpy-based energy savings estimation method targeting thermal comfort level in naturally ventilated buildings in hot-humid summer zones

2017 ◽  
Vol 187 ◽  
pp. 717-731 ◽  
Author(s):  
Yueer He ◽  
Meng Liu ◽  
Thomas Kvan ◽  
Shini Peng
Keyword(s):  
Thermal Comfort ◽  
Energy Savings ◽  
Estimation Method ◽  
Comfort Level ◽  
Naturally Ventilated Buildings
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