scholarly journals Environmental Heat Stress on Indoor Environments in Shallow, Deep and Covered Atrium Plan Form Office Buildings in Tropics

Climate ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 36 ◽  
Author(s):  
Upendra Rajapaksha
Keyword(s):  
Heat Transfer ◽  
Heat Stress ◽  
Internal Heat ◽  
Building Design ◽  
Office Buildings ◽  
Indoor Environments ◽  
Heat Gain ◽  
Indoor Space ◽  
Colombo Plan ◽  
Night Ventilation

Environmental heat stress on buildings through façades contributes to indoor overheating and thus increases demand for energy consumption. The study analyzed the problem, heat gain risk, of modern air-conditioned multi-level office buildings in tropics, for example Colombo. Plan form, orientation, sectional form and envelope were identified and theorized to understand design interventions to reduce the risk of getting heat stress on indoor environments. On-site thermal performance investigations in multi zones of identified three typical built forms, namely; shallow, deep and covered atrium plan forms, quantified the heat stress. Reaching the daytime indoor and surface temperature in peripheral zones of multi-story office buildings during air conditioning “off-mode” up to 38 °C–42 °C was seen as a critical heat stress situation to be addressed through building design. Shading or insulation on façades to control environmental heat gain and manipulation of building section for night ventilation to remove internal heat developed during the daytime are discussed. However, the significance of the plan form depth was found to be a main contributor in dealing with heat transfer to indoor space. Deep plan form was found to be more effective in controlling environmental heat transfer to indoor space across the plan depth.

scholarly journals The Impact of Aspect Ratio on External Heat Gain of Multi-storey Office Buildings in Jakarta

2018 ◽  
Vol 16 (1) ◽  
pp. 24-31
Author(s):  
Wasiska Iyati ◽  
◽  
Eryani Nurma Yulita ◽  
Jusuf Thojib ◽  
Heru Sufianto ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Building Design ◽  
Climatic Conditions ◽  
Building Envelope ◽  
External Heat ◽  
Office Buildings ◽  
Office Building ◽  
Cooling Load ◽  
Heat Gain ◽  
The Impact

The narrow land in big cities such as Jakarta, increases the amount of high rise building, especially multi-storey office building. Office building consumes much energy to provide air conditioning to meet the thermal comfort inside the building. On the other hand, the building shape, building envelope, and building orientation to the sun's position are the main factors in building design aspects that affect the amount of cooling load. This study aims to investigate the impact of the aspect ratio or the ratio of the longer dimension of an oblong plan to the shorter, on external heat gain of multi-storey office building. Variables examined include the transparent and solid area of building envelope, the total area of the surface of the building envelope in any orientation, and the volume of the building, as well as the influence of those proportion on the external heat gain. This study uses mathematical calculations to predict the cooling load of the building, particularly external heat gain through the walls, roof and glass, as well as comparative analysis of models studied. The study also aims to generate the design criteria of building form and proportion of multi-storey office buildings envelope with lower external heat gain. In Jakarta climatic conditions, the result on rectangular building plan with aspect ratio of 1 to 4 shows that the external heat gain did not differ significantly, and the smallest heat gain is found on the aspect ratio of 1.8. Results also showed that the greater aspect ratio, the greater reduction of external heat gain obtained by changing the orientation of the longest side facing east-west into the north-south, about 2.79% up to 42.14% on the aspect ratio of 1.1 to 4. In addition, it is known that in same building volume, changing the number of floors from 10 to 50 can improve the external heat gain almost twice.

scholarly journals Heat Stress Pattern in Conditioned Office Buildings with Shallow Plan Forms in Metropolitan Colombo

Buildings ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 35 ◽  
Author(s):  
Upendra Rajapaksha
Keyword(s):  
Heat Stress ◽  
Thermal Performance ◽  
Morphological Characteristics ◽  
Office Buildings ◽  
Indoor Environments ◽  
Indoor Climate ◽  
Thermal Environments ◽  
Building Characteristics ◽  
The Tropics ◽  
Stress Patterns

This paper critically evaluates indoor overheating of multilevel office buildings in Colombo—a tropical warm humid city. The work questions the building morphological characteristics on thermal performance and indoor climate, thus the levels of Building Energy Indices (BEI) of air conditioned buildings. Pattern of heat stress on buildings due to building characteristics and its relationship to the BEI were identified. A study of 87 multilevel office buildings contributed to identify two critical cases in shallow plan form with similar morphological characteristics such as wall-to-window ratio, aspect ratio, orientation, occupant and equipment density, and façade architecture. A comprehensive thermal performance investigation on these two critical cases quantified the heat stress patterns on their facades and thus indoor thermal environments. Indoor air temperature during office hours in 3 m × 3 m multizones across the depths and lengths in these two buildings showed deviations up to 10.5 °C above the set point temperature level (24 °C). Findings highlight the severity of heat stress on air conditioned indoor environments and the need to address this issue for energy sustainability of urban office buildings in the tropics.

Comparative Performance of a Solar Screen With Respect to Perforation Ratio: Illuminance and Energy Saving

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Esam M. Alawadhi
Keyword(s):  
Design Patterns ◽  
Building Design ◽  
Visual Environment ◽  
Negative Effects ◽  
Comparative Performance ◽  
Heat Gain ◽  
Indoor Space ◽  
Illuminance Level ◽  
Shading Devices ◽  
The Impact

The objectives of sustainable building design are to provide the comfort to the occupants and to eliminate negative environmental impacts of its operations. In this regard, windows play a crucial role in saving energy used for electrical lights and enhancing the indoor visual environment. Excessive sunlight penetration through the windows could increase the heat gains and create the uncomfortable visual environment. Hence, external shading devices, such as solar screens, control the sunlight penetration and minimize its negative effects. The objectives of this research are to provide new insight into the impact of installing the solar screen on the indoor visual environment and heat gain through the window. Experimental measurements are conducted in extreme weather month and window direction, in June and for West facing façade window. Three design patterns of the solar screen were considered with perforation ratios of 12.5%, 25%, and 35%. Without a solar screen, the results show that there is a significant illuminance level variation in the indoor space, between 200 and 2250 Lux. However, if a solar screen with 12.5% perforation ratio is installed, the illuminance level in entire indoor space becomes uniform, it is maintained at 400 Lux during the daytime, and thereby visual comfort is attained. Additionally, the heat gain through the window is decreased by 52.8%, and the window is prevented from heating up during the daytime.

scholarly journals Study on Variation of Internal Heat Gain in Office Buildings by Chronology

Energies ◽  
2018 ◽  
Vol 11 (4) ◽  
pp. 1013 ◽  
Author(s):  
Hyemi Kim ◽  
Kyung-soon Park ◽  
Hwan-yong Kim ◽  
Young-hak Song
Keyword(s):  
Internal Heat ◽  
Office Buildings ◽  
Heat Gain

Experimental investigation of convective heat transfer for night ventilation in case of mixing ventilation

2021 ◽  
Vol 193 ◽  
pp. 107670
Author(s):  
Rui Guo ◽  
Per Heiselberg ◽  
Yue Hu ◽  
Hicham Johra ◽  
Rasmus Lund Jensen ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Experimental Investigation ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Night Ventilation

scholarly journals A Computational Study on the Role of Parameters for Identification of Thyroid Nodules by Infrared Images (and Comparison with Real Data)

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4459
Author(s):  
José R. González ◽  
Charbel Damião ◽  
Maira Moran ◽  
Cristina A. Pantaleão ◽  
Rubens A. Cruz ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thyroid Nodules ◽  
Numerical Study ◽  
Computational Study ◽  
Internal Heat ◽  
Heat Transfer Process ◽  
The Body ◽  
Physical Parameters ◽  
Infrared Sensors ◽  
Wide Range

According to experts and medical literature, healthy thyroids and thyroids containing benign nodules tend to be less inflamed and less active than those with malignant nodules. It seems to be a consensus that malignant nodules have more blood veins and more blood circulation. This may be related to the maintenance of the nodule’s heat at a higher level compared with neighboring tissues. If the internal heat modifies the skin radiation, then it could be detected by infrared sensors. The goal of this work is the investigation of the factors that allow this detection, and the possible relation with any pattern referent to nodule malignancy. We aim to consider a wide range of factors, so a great number of numerical simulations of the heat transfer in the region under analysis, based on the Finite Element method, are performed to study the influence of each nodule and patient characteristics on the infrared sensor acquisition. To do so, the protocol for infrared thyroid examination used in our university’s hospital is simulated in the numerical study. This protocol presents two phases. In the first one, the body under observation is in steady state. In the second one, it is submitted to thermal stress (transient state). Both are simulated in order to verify if it is possible (by infrared sensors) to identify different behavior referent to malignant nodules. Moreover, when the simulation indicates possible important aspects, patients with and without similar characteristics are examined to confirm such influences. The results show that the tissues between skin and thyroid, as well as the nodule size, have an influence on superficial temperatures. Other thermal parameters of thyroid nodules show little influence on surface infrared emissions, for instance, those related to the vascularization of the nodule. All details of the physical parameters used in the simulations, characteristics of the real nodules and thermal examinations are publicly available, allowing these simulations to be compared with other types of heat transfer solutions and infrared examination protocols. Among the main contributions of this work, we highlight the simulation of the possible range of parameters, and definition of the simulation approach for mapping the used infrared protocol, promoting the investigation of a possible relation between the heat transfer process and the data obtained by infrared acquisitions.

Sign in / Sign up

Export Citation Format

Share Document