Surface and Indoor Temperature Effects on User Thermal Responses to Holding a Simulated Tablet Computer

2016 ◽  
Vol 138 (3) ◽  
Author(s):  
Han Zhang ◽  
Alan Hedge ◽  
Beiyuan Guo
Keyword(s):  
Surface Temperature ◽  
Thermal Comfort ◽  
Ambient Temperature ◽  
Heat Dissipation ◽  
Thermal Sensation ◽  
Lower Surface ◽  
Tablet Computer ◽  
Ambient Temperatures ◽  
Surface Temperatures ◽  
Series Of Experiments

A series of experiments was conducted to investigate participant thermal responses to different surface temperatures, from 34 to 44 °C, for a simulated tablet computer in different ambient temperatures (13 °C, 23 °C, and 33 °C). Two subjective measures, thermal sensations and thermal comfort, were reported by the participants. Within the same ambient temperature, participants' thermal sensation and discomfort scores were positively correlated with the increase of surface temperature (higher surface temperatures gave warmer sensations). Thermal comfort also decreases with the increase of surface temperature in the tested range. In addition, ambient temperature moderated the effect of surface temperature on participants' thermal sensation scores. The higher surface temperature of 44 °C was rated warmer at 33 °C than 13 °C, but lower surface temperatures (34–38 °C) were rated less warm at 33 °C than 13 °C. On the other hand, all the surface temperatures were perceived less uncomfortable in an environment at 13 °C environment than at 33 °C. The findings can be used to set limits for future tablet computer heat dissipation designs to improve user's thermal experiences.

Users’ Thermal Response to a Simulated Tablet Computer Surface

2015 ◽  
Author(s):  
Han Zhang ◽  
Alan Hedge ◽  
Beiyuan Guo
Keyword(s):  
Surface Temperature ◽  
Electronic Device ◽  
Thermal Sensation ◽  
Thermal Response ◽  
Heating Surface ◽  
Lower Surface ◽  
Design Guidelines ◽  
Tablet Computer ◽  
Thermal Discomfort ◽  
Computer Controlled

It has been reported that tablet computer surface temperatures can rise from room temperature up to 47°C. Holding a warm or hot computer surface might cause user’s thermal discomfort and possibly skin burns. The use of a tablet often requires holding the device for prolonged time with multiple fingers and palm areas in contact with the tablet lower surface. Previous research has not tested whole finger/palm thermal sensation at a specific surface temperature in a moderate environmental heat range. The current research investigates user’s thermal sensations on the palm and fingers, in response to warm/heat stimuli in a tablet size device with a longer contact duration than used in previous studies, to provide ergonomic design guidelines for electronic device designers and manufacturers. A tablet-size heating surface was developed comprising of nine rectangular aluminum heating pads connected with computer-controlled heaters and thermal sensors. Participants were asked to report their finger/palm thermal sensation and comfort every 45 seconds when they held the prototype for 90 seconds. Results showed a positive linear relationship between surface temperature and user’s thermal sensation and thermal discomfort. Duration of holding the prototype had no significant effect on user’s thermal comfort, but it did significantly affect thermal sensation ratings.

The effect of temperature change rate on user thermal sensation and its implication for tablet computer heat dissipation design

2016 ◽  
Vol 60 (1) ◽  
pp. 785-789 ◽  
Author(s):  
Han Zhang ◽  
Alan Hedge
Keyword(s):  
Surface Temperature ◽  
Temperature Change ◽  
Heat Dissipation ◽  
Thermal Sensation ◽  
Heating Surface ◽  
Rate Of Change ◽  
Effect Of Temperature ◽  
Tablet Computer ◽  
Change Rate ◽  
Temperature Change Rate

Past research has shown that the rate of change of skin surface temperature can affect thermal sensation. This study investigated users’ thermal responses to a tablet heating surface with different heat pads and different temperature change rates. The test conditions included: A. keeping the surface at a constant 42°C, B. increasing the surface temperature from 38°C to 42°C at a rate of 0.02°C/s in progressive intervals, C. increasing the temperature at 0.15°C/s in progressive intervals, and D. Heating two left and right side pads alternately from 38°C to 42°C at 0.15°C/s in progressive intervals. Overall results showed the lowest temperature change rate of 0.02°C/s was most preferred in terms of thermal comfort. The findings suggest a potential to improve user thermal experience by dissipating tablet computer heat at a lower temperature change rate, or by alternating the dissipation areas.

scholarly journals Heat dissipation in subterranean rodents: the role of body region and social organisation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
František Vejmělka ◽  
Jan Okrouhlík ◽  
Matěj Lövy ◽  
Gabriel Šaffa ◽  
Eviatar Nevo ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Heat Dissipation ◽  
Ventral Surface ◽  
Body Region ◽  
Subterranean Rodents ◽  
Ambient Temperatures ◽  
Social Species ◽  
Body Regions ◽  
Body Heat ◽  
Solitary Species

AbstractThe relatively warm and very humid environment of burrows presents a challenge for thermoregulation of its mammalian inhabitants. It was found that African mole-rats dissipate body heat mainly through their venter, and social mole-rats dissipate more body heat compared to solitary species at lower temperatures. In addition, the pattern of the ventral surface temperature was suggested to be homogeneous in social mole-rats compared to a heterogeneous pattern in solitary mole-rats. To investigate this for subterranean rodents generally, we measured the surface temperatures of seven species with different degrees of sociality, phylogeny, and climate using infrared thermography. In all species, heat dissipation occurred mainly through the venter and the feet. Whereas the feet dissipated body heat at higher ambient temperatures and conserved it at lower ambient temperatures, the ventral surface temperature was relatively high in all temperatures indicating that heat dissipation to the environment through this body region is regulated mainly by behavioural means. Solitary species dissipated less heat through their dorsum than social species, and a tendency for this pattern was observed for the venter. The pattern of heterogeneity of surface temperature through the venter was not related to sociality of the various species. Our results demonstrate a general pattern of body heat exchange through the three studied body regions in subterranean rodents. Besides, isolated individuals of social species are less able to defend themselves against low ambient temperatures, which may handicap them if staying alone for a longer period, such as during and after dispersal events.

scholarly journals Influence of Ambient Temperature on Radiative and Convective Heat Dissipation Ratio in Polymer Heat Sinks

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2286
Author(s):  
Jan Kominek ◽  
Martin Zachar ◽  
Michal Guzej ◽  
Erik Bartuli ◽  
Petr Kotrbacek
Keyword(s):  
Heat Transfer ◽  
Ambient Temperature ◽  
Convective Heat ◽  
Heat Dissipation ◽  
High Surface ◽  
Heat Sinks ◽  
Fourth Power ◽  
Molding Process ◽  
Ambient Temperatures ◽  
University Of Technology

Miniaturization of electronic devices leads to new heat dissipation challenges and traditional cooling methods need to be replaced by new better ones. Polymer heat sinks may, thanks to their unique properties, replace standardly used heat sink materials in certain applications, especially in applications with high ambient temperature. Polymers natively dispose of high surface emissivity in comparison with glossy metals. This high emissivity allows a larger amount of heat to be dissipated to the ambient with the fourth power of its absolute surface temperature. This paper shows the change in radiative and convective heat transfer from polymer heat sinks used in different ambient temperatures. Furthermore, the observed polymer heat sinks have differently oriented graphite filler caused by their molding process differences, therefore their thermal conductivity anisotropies and overall cooling efficiencies also differ. Furthermore, it is also shown that a high radiative heat transfer leads to minimizing these cooling efficiency differences between these polymer heat sinks of the same geometry. The measurements were conducted at HEATLAB, Brno University of Technology.

The Influence of Micro Scale Ratchet Depth on the Motion of Leidenfrost Drop

2015 ◽  
Author(s):  
Jeong Tae Ok ◽  
Sunggook Park
Keyword(s):  
Surface Temperature ◽  
Water Drop ◽  
Lower Surface ◽  
Driving Mechanism ◽  
Entire Surface ◽  
Depth Effect ◽  
Micro Scale ◽  
Temperature Range ◽  
Aspect Ratios ◽  
Surface Temperatures

The influence of ratchet depth on the motion of Leidenfrost water drop was investigated as a continuous effort to reveal the driving mechanism. Continuous directional rebounding behavior of the drop was observed only at below 200°C on both micro ratchets with two different depth-to-period aspect ratios (1:5 and 1:10) and sharp ridges. Overall, the shallow ratchets generated more efficient drop mobility in the entire surface temperature range of 193–299°C due to the increased area between the bottom of the drop and the ratchet surface, caused by the geometrical benefit. However, the depth effect was only critical at relatively lower surface temperatures.

The Effect of Surface Texture on Thermal Sensation and Comfort

2017 ◽  
Author(s):  
Han Zhang ◽  
Alan Hedge
Keyword(s):  
Thermal Comfort ◽  
Spatial Patterns ◽  
Surface Texture ◽  
Smooth Surface ◽  
Thermal Sensation ◽  
Electronic Devices ◽  
Material Surface ◽  
Tablet Computer ◽  
Physical Sensation ◽  
Effect Of Surface

The study investigated how the material roughness of a tablet computer surface can affect thermal sensation and comfort of users fingers and palms at different surface temperatures. Three levels of pattern spacing were tested, and it was shown that rough material surface provided higher thermal comfort comparing to a smooth surface. In addition, the surface temperature of the material also moderates participants′ physical sensation of the roughness of the materials. The results of the study have shown evidences of the potentials to use materials with spatial patterns to improve thermal comfort while dissipating heat from electronic devices.

Thermal comfort in relation to mean skin temperature

1970 ◽  
Vol 48 (2) ◽  
pp. 98-101 ◽  
Author(s):  
E. D. L. Topliff ◽  
S. D. Livingstone
Keyword(s):  
Thermal Comfort ◽  
Ambient Temperature ◽  
Skin Temperature ◽  
Incident Radiation ◽  
Mean Skin Temperature ◽  
Ambient Temperatures ◽  
The Mean ◽  
Per Se

Nude men were exposed to a range of ambient temperatures and were brought to a condition of thermal comfort by adjustment of the incident radiation. The mean skin temperature associated with comfort was found to be different for each combination of ambient temperature and incident radiation. It was evident that mean skin temperature, per se, was not a dependable criterion of thermal comfort.

The Benefits of Tree Shade and Turf on Globe and Surface Temperatures in an Urban Tropical Environment

2020 ◽  
Vol 46 (3) ◽  
pp. 228-244
Author(s):  
Lai Fern Ow ◽  
Subhadip Ghosh ◽  
Mohamed Lokman Mohd Yusof
Keyword(s):  
Thermal Comfort ◽  
Urban Areas ◽  
Mitigation Strategies ◽  
Urban Heat Islands ◽  
Outdoor Thermal Comfort ◽  
Mitigation Measures ◽  
Heat Islands ◽  
Ambient Temperatures ◽  
Surface Temperatures ◽  
Island State

The process of urbanisation increases temperature and alters the thermal comfort in cities. Urban heat islands (UHIs) result in the rise of ambient temperatures. For example, in the densely populated island state of Singapore, the UHI intensity was some 4.5 °C. Such elevation in heat can negatively impact outdoor thermal comfort and may give rise to serious health problems. The present study investigated the benefits of trees and turf as mitigation strategies for urban areas. Short- and long-term observations were made for surface and globe temperatures over smaller plots of vegetation and hard surfaces involving tree shade and full sun. Similar observations were investigated over a larger extent of vegetation across concrete, asphalt, and turf within an urban park setting. The presence of turf and shade from trees greatly affected surface temperatures, and the effect was most pronounced when both were present. The presence of turf reduced surface temperatures by up to 10 °C, while tree shade led to a 12 °C reduction. Globe temperatures showed that the presence of turf and shading reduced temperatures between 5 and 10 °C. These results suggest that turf and trees can effectively cool surfaces and improve outdoor thermal comfort. The results of this study can be applied to urban planning of greenery and can be used as a reference for other tropical cities with similar climates that are also working to develop mitigation measures to improve the liveability of their cities.

scholarly journals Acceptable surface temperature of floor radiant heating system based on thermal comfort study in southern China

2019 ◽  
Vol 80 ◽  
pp. 03007
Author(s):  
Xingyu Lu ◽  
Hong Liu ◽  
Yuxin Wu
Keyword(s):  
Surface Temperature ◽  
Thermal Comfort ◽  
Thermal Sensation ◽  
Southern China ◽  
Heat Exposure ◽  
Cumulative Effect ◽  
Heating System ◽  
Radiant Heating ◽  
Floor Surface ◽  
Floor Temperature

In winter, people's demand for heating is stronger and stronger in southern China, and the floor radiant heating system is more and more popular. However, there are no suitable guidelines or standards for the floor temperature of the heating system in this area. The insulation performance of buildings in southern is not as good as other area which have central heating system. So the acceptable floor temperature suitable for this area needed to be studied.12 healthy college students participated as samples in this experiment. The floor surface temperature was controlled by varying the temperature of water flowing underneath the floor. The main conclusions were as follows: 1) the floor surface temperature directly affected the skin temperature of the foot and the thermal comfort of the foot. There was a significant statistical relationship between the floor surface temperature and the overall thermal sensation. 2) The acceptable floor temperature ranged from 26.1 °C to 34.3 °C for sitting positions and 24.6 °C ~34.7 °C for standing positions. 3) Considering the head thermal comfort and the health effects of the cumulative effect of long-term heat exposure, the recommended upper limit of the floor temperature in this experiment is 31°C.

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