Improved Thermal Comfort of Helmets for Two-Wheeler Motorcycles: Technical Note

2020 ◽  
Vol 12 (3) ◽  
Author(s):  
S. Thirumurugaveerakumar
Keyword(s):  
Thermal Properties ◽  
Thermal Comfort ◽  
Technical Note ◽  
Structural Safety ◽  
Critical Importance ◽  
Design Features ◽  
Thermal Discomfort ◽  
Design Concepts ◽  
Head Form ◽  
Two Wheeler

A helmet used by motorcyclists is always of critical importance for the safety of the rider. A well-designed helmet should be able to absorb as much energy as possible and to diffuse it to the whole helmet during an impact. This project is intended to improve the design features with respect to thermal comfort of Helmet shell. The vital design features of helmets are extent of protection, ISO head form, and peripheral visions. Thermal discomfort can cause rider fatigue thereby reducing the overall concentration during driving. Various design concepts, such as adding ventilation holes, increasing clearance between the helmet shell and the head and covering the shell with reflective materials, are used to improve the thermal properties. The existing design of helmets does not account for the thermal comfort of the helmet shell into consideration so, a new design prototype is developed. At this stage, attention was also paid to structural safety, appearance and manufacturability. The thermal comforts that can be derived from this design are significantly improved over other commercially available helmets.

scholarly journals Numerical evaluation of thermal discomfort in conditions of surface heating and asymmetric radiation

2018 ◽  
Vol 9 (2) ◽  
pp. 175-179
Author(s):  
F. Kalmár ◽  
T. Kalmár
Keyword(s):  
Thermal Properties ◽  
Thermal Comfort ◽  
Winter Period ◽  
Negative Effects ◽  
Air Velocity ◽  
Thermal Discomfort ◽  
External Wall ◽  
Wall Heating ◽  
Personalized Ventilation ◽  
Radiant Temperature

This paper presents the results of analytical analysis of thermal comfort and radiation asymmetry in case of wall heating depending on the room geometry and thermal properties of the external wall. The negative effects of radiation asymmetry on thermal comfort in case of summer conditions can be lowered using advanced personalized ventilation systems. In case of buildings with poor thermal properties of the envelope during the winter period low surface temperatures may occur. The aim of this research was to analyse the thermal asymmetry in the case of a room with one external wall and wall heating installed on the opposite wall. It was assumed that the radiation asymmetry will lead to discomfort and it was hypothesised that the discomfort might be reduced increasing the air velocity. The results have proven that thermal asymmetry in the middle of the room will not lead to thermal discomfort even for walls without any additional thermal insulation. However, the mean radiant temperature varies significantly depending on the position of the occupant in the room. In this case, the personalized control on the air velocity can help to improve the thermal comfort conditions.

Continuing Airworthiness Challenges

1994 ◽  
Vol 47 (6S) ◽  
pp. S145-S150
Author(s):  
Ulf G. Goranson
Keyword(s):  
Structural Integrity ◽  
Structural Safety ◽  
Design Features ◽  
Design Concepts ◽  
Design Considerations ◽  
Detail Design ◽  
Attention To Detail

Structural safety is an evolutionary accomplishment, and attention to detail design features is key to its achievement. A multitude of design considerations is involved in ensuring the structural integrity of Boeing jet transports that have common design concepts validated by extensive analyses, tests, and three decades of service. As airplanes approach their design service objectives, the incidences of fatigue and corrosion may become widespread. Continuing airworthiness of the aging jet fleet requires diligent performance from the manufacturer, the airlines, and airworthiness authorities.

scholarly journals Thermal performance and concentration of gases in facilities for pigs in semiarid region from State of Paraiba - Brazil

2012 ◽  
Vol 32 (1) ◽  
pp. 30-37 ◽  
Author(s):  
Dermeval A. Furtado ◽  
Daniele Amancio ◽  
José W. B. do Nascimento ◽  
Josivanda P. Gomes ◽  
Rafael C. Silva
Keyword(s):  
Carbon Monoxide ◽  
Thermal Comfort ◽  
Rainy Season ◽  
Dry Season ◽  
International Standards ◽  
Semiarid Region ◽  
Thermal Discomfort ◽  
Rainy Period ◽  
Globe Temperature ◽  
The Times

The study was conducted in a facility for pigs during the nursery and finishing in the town of 'Montadas', in the semiarid of the state of Paraiba, Brazil, in the rainy and dry season, aiming to evaluate the concentration of oxygen, methane, carbon monoxide and ammonia, and the bioclimatic indexes: ambient temperature (AT), relative humidity (RH) and the index of black globe temperature and humidity (IBGTH). These indexes differed significantly (P>0.05) between the periods and times. The AT in the rainy season was in the thermal comfort zone(TCZ) in most of the times in the nursery; for the finishing phase, thermal discomfort occurred; during the dry season, there was thermal comfort in the nursery phase; in the finishing phase the thermal discomfort occurred at all times. In the rainy season, the IBGTH was in TCZ; in the dry season, it was above the TCZ. The RH in the rainy period was in the TCZ; in the dry season, in most of the times, below the range of the TCZ. The concentration of gases showed no differences (P > 0.05) between periods and between the times, and the carbon monoxide, hydrogen sulfide and methane were below 1.0 ppm, and the ammonia showed a mean of 5.2 ppm. None of the analyzed gases exceeded the limits established by Brazilian and international standards for animals and workers.

A Study on Morphology of HongKong Shopping Centers

2012 ◽  
Vol 174-177 ◽  
pp. 1796-1800
Author(s):  
Ye Zi Dai
Keyword(s):  
Local Condition ◽  
Shopping Centers ◽  
Design Features ◽  
Interior Space ◽  
Design Concepts

It has been several decades since HongKong developed shopping centers. During the process, a set of design concepts, which in accordance with actual local condition, were produced. By studying the Morphology of HongKong shopping centers about exterior environment and interior space, the article tried to analysis their design features as well as the experiences we can learn from.

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 A Study of the Thermal Environment and Air Quality in Hot–Humid Regions during Running Events in Southern Taiwan

Atmosphere ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 1101
Author(s):  
Si-Yu Yu ◽  
Andreas Matzarakis ◽  
Tzu-Ping Lin
Keyword(s):  
Air Quality ◽  
Solar Radiation ◽  
Thermal Comfort ◽  
Real Time ◽  
Thermal Environment ◽  
Monitoring Data ◽  
Integrated Analysis ◽  
View Factor ◽  
Thermal Discomfort ◽  
Southern Taiwan

It is quite difficult to investigate thermal comfort in hot–humid regions, and there have not been many real case studies or research related to this issue. In this article, four running events held in nearby popular travel spots in Kaohsiung, the largest city in southern Taiwan, were selected to analyze the influence of thermal environment and air quality on thermal comfort. Mostly real time environmental monitoring data were applied for estimating thermal indicators, along with Sky View Factor (SVF) data taken at the sites of the running scheduled routes, to analyze the thermal performance of participants at running events. Compared with runners, walkers (local residents, fans, and staff of the events) would be exposed to a greater risk of thermal discomfort with increasing time spent on the routes. With the integrated analysis, mPET (modified physiologically equivalent temperature) can be viewed as a relatively comprehensive indicator in considering both environmental thermal conditions and the biometrical differences of activities and clothing types. From the results, a good correlation between mPET and solar radiation/SVF was obtained, which indicated that mPET could be sufficiently sensible in revealing the thermal condition variation from one site to another during the route with time. Based on the discomfort risk assessment, for runners, the event held in autumn with lower SVF at the route sites would be less risky of thermal discomfort, while the event held in spring with lower solar radiation would be more comfortable for walkers. As for air quality condition, the inappropriateness of holding winter outdoor activities in Kaohsiung was obviously shown in both real time monitoring data and long term analysis.

scholarly journals Building and Urban Cooling Performance Indexes of Wetted and Green Roofs—A Case Study under Current and Future Climates

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6192
Author(s):  
Madi Kaboré ◽  
Emmanuel Bozonnet ◽  
Patrick Salagnac
Keyword(s):  
Thermal Comfort ◽  
Emission Scenario ◽  
Green Roof ◽  
Heat Fluxes ◽  
Temperate Climate ◽  
Passive Cooling ◽  
Thermal Discomfort ◽  
Indoor Thermal Comfort ◽  
Performance Indexes ◽  
The Impact

We developed and studied key performance indexes and representations of energy simulation heat fluxes to evaluate the performance of the evaporative cooling process as a passive cooling technique for a commercial building typology. These performance indexes, related to indoor thermal comfort, energy consumption and their interactions with their surrounding environments, contribute to understanding the interactions between the urban climate and building for passive cooling integration. We compare the performance indexes for current and future climates (2080), according to the highest emission scenario A2 of the Special Report on Emission Scenario (SRES). Specific building models were adapted with both green roof and wetted roof techniques. The results show that summer thermal discomfort will increase due to climate change and could become as problematic as winter thermal discomfort in a temperate climate. Thanks to evapotranspiration phenomena, the sensible heat contribution of the building to the urban heat island (UHI) is reduced for both current and future climates with a green roof. The performance of the vegetative roof is related to the water content of the substrate. For wetted roofs, the impacts on heat transferred to the surrounding environment are higher for a Mediterranean climate (Marseille), which is warmer and drier than the Paris climate studied (current and future climates). The impact on indoor thermal comfort depends on building insulation, as demonstrated by parametric studies, with higher effects for wetted roofs.

Optimal Minimum Airflow for Air Circulation of Single-Duct VAV Terminal Boxes

2008 ◽  
Author(s):  
Young-Hum Cho ◽  
Mingsheng Liu
Keyword(s):  
Thermal Comfort ◽  
Air Temperature ◽  
Thermal Discomfort ◽  
Variable Air Volume ◽  
Air Handling Unit ◽  
Optimal Value ◽  
Computational Fluid Dynamics Simulations ◽  
Dynamics Simulations ◽  
Air Circulation ◽  
The Impact

Thermal comfort in an area is directly controlled by terminal boxes in variable air volume (VAV) air-handling unit (AHU) systems. The terminal box either modulates airflow or adjusts the discharge air temperature. Reduced air circulation will cause thermal discomfort in a conditioned space if the airflow and discharge air temperature are not suitable. The objective of this study is to identify an optimal value for airflow and discharge air temperature that will maintain room thermal comfort. Optimal room airflow and discharge air temperature is analyzed, and the impact of room airflow and discharge air temperature on thermal stratification is verified through CFD (Computational Fluid Dynamics) simulations.

scholarly journals Evaluating the Perception of Ventilation for Thermal Comfort in Senate Buildings: A Case of Nigeria Universities

2018 ◽  
Vol 9 (1) ◽  
pp. 1-9
Author(s):  
Ayeni Conqueror A. ◽  
Ayinla A. Kunle ◽  
Ajayi Oluwole
Keyword(s):  
Thermal Comfort ◽  
Direct Observation ◽  
Natural Ventilation ◽  
Physical Characteristics ◽  
Office Buildings ◽  
Thermal Discomfort ◽  
South West ◽  
Survey Results ◽  
Major Factors ◽  
Window Condition

Window condition is one of the major factors of ventilation in office buildings. The study aimed at evaluating the natural ventilation in Senate buildings of selected Universities in South-West Nigeria. The study employed the use of questionnaires survey to solicit information on subjective feelings of the occupants on the effects of thermal opening and thermal comfort in Senate buildings offices. Direct observation was carried out to obtain information on the physical characteristics of the selected buildings. Limited research has been recorded on the study of occupants’ feelings in buildings in relation to openings in buildings. Based on the survey results, it was found that 34.0% of the windows were casement type, 30.0 % were projected 25.5% were sliding; while 9.5% were the louvred type. The study showed that 73.8% of the respondents preferred the casement window type because of its easiness in operation to other window types and improved thermal comfort on occupants. The study concluded that with adequate sizes, casement window type is the best in ameliorating the effect of thermal discomfort in Senate Buildings.  

scholarly journals Influence of Knitting Process Parameters on the Thermal Comfort Properties of Eri Silk Knitted Fabrics

2018 ◽  
Vol 26 (5(131)) ◽  
pp. 47-53 ◽  
Author(s):  
Balakrshnan Senthil Kumar ◽  
Thangavelu Ramachandran
Keyword(s):  
Thermal Properties ◽  
Thermal Comfort ◽  
Process Parameters ◽  
Loop Length ◽  
Knitted Fabrics ◽  
Vertical Wicking ◽  
Yarn Count ◽  
Thermal Comfort Properties ◽  
Fabric Structures ◽  
Eri Silk

Eri silk, a wild silk variety available in the northeastern states of India, has better softness, tensile and thermal properties. The present study aimed to develop different knitted structures and investigate the influence of knitting process variables on the thermal comfort and wicking properties. Knitted single jersey and single pique fabric structures were produced with two sets of yarns – 25 tex and 14.32 tex with three levels of loop length. Thermal properties of the fabric were analysed using an Alambeta instrument, and the wicking ability was measured with an vertical wicking tester. Thermal comfort properties of eri silk were also compared with those of conventional mulberry silk, with the experiment result revealing that eri silk has better comfort values. A statistically significant correlation is found between knitting process parameters viz. the yarn count, loop length knitting structure and the thermal and wickability values of the fabrics.

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