• KIEAE Journal
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• v.16 no.5
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• pp.29-37
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• 2016

Purpose: Indoor thermal comfort can be identified by combination of temperature, humidity, and air flow, etc. However, most thermal indexes in regard to thermal comfort are temperature dominant since it has been considered as a significant factor affecting to indoor thermal comfort The purposes of this study are to investigate indoor neutral temperature range of young Koreans with humidity perception, and to introduce a neutral temperature for temperature preference as well as temperature sensation in order to define the neutral temperature range chosen by occupants. It could be used as basic data for heating and cooling. Method: 26 research participants volunteered in 7 thermal conditions ($18^{\circ}C$ RH 30%, $18^{\circ}C$ RH 60%, $24^{\circ}C$ RH 30%, $24^{\circ}C$ RH 40%, $24^{\circ}C$ RH 60%, $30^{\circ}C$ RH 30%, $30^{\circ}C$ RH 60%) and completed subjective assessment in regard to temperature/humidity sensation and preference twice per condition in an indoor environmental chamber. Result: In RH 30%, sensation neutral temperature was $25.1^{\circ}C$ for men and $27.0^{\circ}C$ for women, and preference neutral temperature was $25.5^{\circ}C$ for men and $27.8^{\circ}C$ for women. In RH 60%, sensation neutral temperature was $23.6^{\circ}C$ for men and $25.9^{\circ}C$ for women, and preference neutral temperature was $23.4^{\circ}C$ for men and $26.3^{\circ}C$ for women. Neutral temperature increased with increasing relative humidity. Women were sensitive to humidity changes. Men expressed humidity changes as temperature variations. In most conditions, preference neutral temperatures were higher than sensation neutral temperatures, however, the preference neutral temperature for men in humid condition was lower than the sensation neutral temperature.

• Korean Journal of Agricultural Science
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• v.50 no.4
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• pp.663-673
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• 2023

The purpose of this study was to scientifically activate the forest healing program activities for the elderly. The predicted mean vote (PMV) and predicted percentage of dissatisfied (PPD), which are indices of thermal comfort in the thermal environment, and degree of canopy closure were compared and analyzed. Based on this information, the study objective was to present the appropriate conditions for maintaining the best comfort for the elderly. Six deck road shelters, which are the most active locations in forest healing programs among the National Center for Forest Therapy, were selected as the study sites. The results indicated that in the case of the conditions of 1 clo (clothing insulation value) and 1 met (metabolic rate) at an air temperature of 19 to 21 degrees in September on the measurement date, the PMV values ranged between -1.85 and -0.98 at all sites, and PPD values ranged between 25.60% and 68.68%. On the other hand, in the case of 1.3 clo and 1.6 met conditions, the PMV values ranged between -0.08 and 0.23 for all sites and PPD values ranged between 5.40 and 6.18. As shown above, the difference in thermal environment comfort and satisfaction according to the condition of the amount of metabolism and the amount of clothing could be confirmed. In addition, an analysis of the relation between PPD and canopy closure suggested a significantly positive correlation between them, and it was found that canopy closure was a factor affecting thermal comfort. Studies on effects of forest thermal environmental comfort and canopy closure on forest healing program areas should be conducted extensively according to seasonal conditions to provide information that can be used for more effective forest healing programs.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.9
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• pp.610-619
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• 2011

This paper investigates the simplified comfort index and control logic for VRF (Variable Refrigerant Flow) system by using 3 environmental factors such as temperature, humidity and air flow. Indoor test under thermal load was conducted to explore relationship of each environment factors that is related to simplified comfort index. Simplified comfort function that has 3 environmental variables was proposed based on survey results. Each factor is measured and comfort preference was surveyed by more than 30 subjects in the indoor comfort test. Moreover, control logic for VRF system was developed and then simulated by using thermal load calculation method and verified with test. The proposed comfort function was in good agreement with survey results, and also verification test trend of comfort change and maintenance are quite similar with survey. Furthermore, through the additional test data analysis some differences of comfort according to position of people staying in the test room were additionally investigated by air flow. People being under an exit of air in the indoor air-conditioner feel more comfortable condition and speed of response to comfort change is relatively fast.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.5
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• pp.477-486
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• 2005

In this study, indoor thermal environment, resident behavior of operating cooling device, and thermal comfort vote are investigated at the living room of apartment during summertime in Seoul. Based on the results of the investigation, indoor air temperatures that residents turn air conditioners (especially for cooling load in this research) on and off were found out. The relationships between outdoor weather condition and the number of days using air conditioner, and whether operating patterns of the devices were also found out. The acceptable thermal comfort zone is figured out from these results, and this research is expected to contribute to the development of household air conditioner. The results can be summarized as the followings; Residents turned the air conditioner on at $29.76^{\circ}C$ of indoor air temperature, and $28.89^{\circ}C$ of $SET^\ast$. And turned the air conditioner off at $27.31^{\circ}C$ of indoor air temperature, and $23.70^{\circ}C$ $SET^\ast$. Therefore, acceptable thermal comfort zone could be lied between these temperatures. If comfortable indoor thermal environment can be obtained with various architectural passive cooling techniques based on the results, energy consumption of cooling devices will be reduced.

• Journal of Fisheries and Marine Sciences Education
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• v.18 no.1
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• pp.11-18
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• 2006

Man has always striven to create a thermally comfortable environment. This is reflected in building traditions around the world - from ancient history to present day. Today, creating a thermally comfortable environment is still one of the most important parameters to be considered when designing buildings. It is defined in the ISO 7730 standard as being "That condition of mind which expresses satisfaction with the thermal environment". A definition most people can agree on, but also a definition is not easily converted into physical parameters. Thermal comfort is a matter of many physical parameters, and not just one, as for example the air temperature that is set by air-conditioner. The most important matter Today's common offices and homes are only depending on air-conditioning as a cooling system during the summer. This kind of system tends to be focused on the person who controls it and those who are around the air-conditioner while thermal-comfort is neglected. Futhermore, the people's body conditions are not considered during each time that beginning, middle, last of the air-conditioning which causing displeasure of the residents more and more. This kind of operating system is set for a long time may causes unbalanced air condition and man's psychologic displeasure goes to increase.

• Fashion & Textile Research Journal
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• v.11 no.6
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• pp.947-952
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• 2009

The purpose of this study is to analyze skin wettedness($w$) used as the rate index of thermal comfort, and to evaluate the wear comfort of outdoorwear. Skin wettedness is widely used to express the degree of thermal comfort. If skin wettedness exceeds a certain threshold, the body feels damp and discomfort. An experiment which consisted of rest(30 min), exercise(30 min) and recovery(20 min) periods was administered in a climate chamber with 10 healthy male participants. Two kinds of outdoorwears made of 100% cotton fabrics (Control) and specially engineered fabrics having feature of quick sweat absorbency and high speed drying fabric (Functional) were evaluated in the experiment. The condition of climate chamber was controlled according to the thermal insulation of 4 kinds of experimental ensembles(E1~E4). Total sweat loss, sweat loss absorbed into clothing and skin temperature were measured. Skin wettedness was calculated from the ratio of evaporative rate to the maximal evaporative capacity. Skin wettedness of 'Functional' was lower than 'Control' in the 3 kinds of ensembles(E1, E2, E4) because the materials of 'Functional' were composed of quick sweat absorbency and high speed drying fabrics, water vapour permeability and waterproof fabrics.

• Journal of Climate Change Research
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• v.7 no.3
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• pp.357-371
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• 2016

Buildings in the city acts as a cause of distorted wind direction, wind speed, causing the stagnation of the air flow. In the recent trend of climate change can not but consider the temperature rise of the urbanization. This study was aimed to analyze the thermal comfort of planetary boundary layer in different artificial constructions areas which has a direct impact on urban climate, and estimating the warming phenomena. Envi-met model was used to consider the urban structure associated with urban growth in order to precisely determine the impact of the building on the city weather condition. The analyzed values of thermal comfort index were temperature, wind speed, horizontal and vertical turbulent diffusivity. In particular, analysis of the PPD(Predicted Percentage of Dissatisfied) represents the human thermal comfort. In this study, by adjusting the arrangement and proportion of the top floor building in the urban it was found that the inflow of the fresh air and cooling can be derived low PPD. Vertical heat flux amount of the city caused by climate change was a factor to form a high potential temperature in the city and the accumulation of cold air does not appear near the surface. Based on this, to make the city effectively respond to climate change may require a long-term restructuring of urban spatial structure and density management.

• Journal of the Korean Home Economics Association
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• v.42 no.10 s.200
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• pp.91-104
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• 2004

The purpose of this study was to examine the differences of clothing microclimates and the subjective sensations according to age, gender and clothing weight for $19^{\circ}C$ air temperature. This study was done to gain fundamental data related to saving heating energy and to improve health through wearing underwear (long johns) in lower indoor temperatures. The subjects were divided into four groups (6 young males, 5 young females, 6 old males, 6 old females), and our experiment consisted of three conditions; the first condition was wearing long underwear in $19^{\circ}C$ air (19CUW condition); the second condition was without wearing long underwear in $19^{\circ}C$ air (19C condition); and the third condition was without wearing underwear in $24^{\circ}C$ air (24C condition). The experiment showed that the clothing microclimate temperature and humidity was the lowest in the 19C condition and the highest in the 24C condition irrespective of age and gender. The clothing microclimate in the 19CUW condition was not significantly distinguishable from the other conditions. Clothing microclimate temperature and humidity when the subjects responded thermal comfort was $28\~34^{\circ}C$ and $15\~40\%$RH without any significant difference according to age and gender. For the thermal sensation, the 24C condition was regarded as the warmest environment by the four groups, and the next preference was the 19CUW condition (p<0.001). Young females and old males showed a tendency to feel colder than young males and old females. For the thermal sensation of hands and feet, the young groups felt the warmest in the 24C condition and the coolest in the 19 C condition (p<0.001). However, old males felt neutral for the foot thermal sensation without any significant difference between the three conditions. Old females felt neutral for both the hands and feet thermal sensations without any significant difference between the three conditions. Thermal preference was the highest in the 24C condition for the 4 groups. In the 19CUW condition, for the thermal preference, most young males and females responded 'No change'; on the other hand, mea of the old responded 'Warmer'(p<0.001). It was the 24C condition that the 4 subject groups felt the most thermally comfortable. In the 19CUW condition, over $80\%$ of responses of each group expressed satisfaction and in the 19C condition, over $80\%$ of responses of each group, except young females, expressed satisfaction. In conclusion, in view of the clothing microclimate and subjective sensations, the 24C condition was the condition that gave subjects the least cold stress and the best subjective preference. However, the 19C condition and the 19CUW condition was not such a cold stress as to give healthy subjects a thermal burden.

• Journal of the Korean Solar Energy Society
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• v.24 no.4
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• pp.45-53
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• 2004

In the summer, the irradiated solar heat gain through the roof has an effect on the thermal environment of the top floor units of apartment houses. This paper investigated the differences of the indoor air temperature and thermal comfort index between the top floor unit and the middle floor unit by measuring them at the sample houses. The purpose of this paper is to provide quantitative data about the irradiated solar heat gain during the summertime through the roof of an apartment house and these data to be the source to reevaluate the appropriate roof insulation efficiency. From this study, we obtained the brief results as follows. Indoor air temperature at the top floor unit is $1.2\sim2.2^{\circ}C$ higher than that of middle floor unit. The evaluation of the indoor thermal comfort index at each sample rooms reveals notable thermal differences between the two units. Top floor units need more cooling load during the summertime compared to middle floor units. Therefore, solutions to reduce solar Heat gain at top floor units to be considered.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.5
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• pp.115-123
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• 2010

Cool-down performance after soaking is important because it affects passenger's thermal comfort. The cooling capacity of HVAC system determines initial cool down performance in most cases, the performance is also affected by location, and shape of panel vent, indoor seat arrangement. Therefore, optimal indoor designs are required in developing a new car. In this paper, initial cool down performance is predicted by CFD(computational fluid dynamics) analysis. Experimental time-averaging temperature data are used as inlet boundary condition. For more reliable analysis, real vehicle model and human FE model are used in grid generation procedure. Thermal and aerodynamic characteristics on re-circulation cool vent mode are investigated using CFX 12.0. Thermal comfort represented by PMV(predicted mean vote) is evaluated using acquired numerical data. Temperature and velocity fields show that flow in passenger's compartment after soaking is considerably unstable at the view point of thermodynamics. Volume-averaged temperature is decreased exponentially during overall cool down process. However, temperature monitored at different 16 spots in CFX-Solver shows local variation in head, chest, knee, foot. The cooling speed at the head and chest nearby panel vent are relatively faster than at the knee and foot. Horizontal temperature contour shows asymmetric distribution because of the location of exhaust vent. By evaluating the passenger's thermal comfort, slowest cooling region is found at the driver's seat.