Subjective Ratings Of Comfort Research Articles

Dynamic Characteristics and Optimization of Segmented Fork Arm Seat System

To improve the low-frequency vibration isolation performance and driving comfort of the engineering seat system, a segmented fork arm seat system is proposed. Firstly, the equivalent model of the n-level segmented seat system is established, the amplitude-frequency response function and phase-frequency response function of the segmented seat system are solved and analyzed. The theoretical study shows that, with the increase of segment levels, the response time of the seat system is shortened, and the attenuation rate of response amplitude is accelerated; with the increase of segment levels, the resonance peak value of the seat system tends to shift continuously, and the low-frequency vibration isolation range expands. Secondly, according to the actual application condition of a loader, the engineering structure of the 3-level segmented fork arm seat system was built, and the structure-stiffness parameters of the segmented fork arm seat system were optimized by multi-objective genetic algorithm. The optimization results show that the 3-level segmented fork arm seat system has obvious vibration reduction effect on the sensitive frequency band of the human body. The vibration reduction effect on road excitation increases by 63.2% on average under driving conditions, 75.8% on uneven road surface, and 65.2% under operating conditions, and the subjective comfort evaluation index of human body increases by two levels.

Effects of interactions between thermal and acoustic environments on subjective comfort evaluations in outdoor public spaces

ABSTRACT In this study, five outdoor open areas were selected as the study sites to investigate the effects of thermal and acoustic environments, physical activity levels, and pleasantness on evaluations of the thermal and acoustic comfort in outdoor open spaces. Survey questionnaires and on-site measurements were used to quantitatively assess human thermal and acoustic comfort in outdoor spaces. The following findings were obtained in this study. The acoustic environment affected the thermal sensation, where reducing excessive outdoor noise levels could enhance thermal comfort. Increasing the physiological equivalent temperature amplified the acoustic sensation. Individuals reported the most comfortable acoustic perception outdoors at a physiological equivalent temperature of 30.1°C. Reducing both the thermal and acoustic indices improved the overall comfort to some extent. Decreasing physical activity levels by an appropriate amount enhanced the thermal comfort, acoustic comfort, and overall comfort. Finally, maintaining a sense of pleasantness was conducive to increasing the thermal comfort, acoustic comfort, and overall comfort. In states of moderate and pleasurable feelings (pleasantness level = 0, 1, 2, 3), increased acoustic comfort and pleasantness combined significantly enhanced the thermal comfort.

Thermal perception and satisfaction of Italian students in distance (home) learning vs face-to-face learning environments during the heating season

During the 2020-2021 COVID-19 pandemic situation, millions of high school students in Italy had to adapt a room in their home for partial distance learning. This paper investigates the thermal perception and satisfaction with the thermal conditions expressed by 45 teenage students alternating between Distance Learning (DL) and Face-to-face learning (FL) during that period. Students completed questionnaires about their perception and satisfaction with the thermal environment while air temperature and humidity were monitored for 14 weeks. The thermal conditions in the classrooms, where students attended classes every other day, were also monitored during this time. The results show that students at home experienced a high percentage of time with conditions outside recommended comfort limits. Nevertheless, most of the students expressed a TSV equal to 0. In addition, the proposed long-term thermal discomfort indicators, such as running mean of the indoor air temperature, correlated rather poorly with subjective votes. This may indicate that different indices should be considered when analyzing mid-term subjective thermal comfort evaluations.

Testing the applicability of CIBSE overheating criteria to Australian subtropical residential contexts

Overheating is widespread across diverse building typologies. In the context of global warming, it is becoming increasingly problematic in naturally-ventilated dwellings in which air-conditioning is not an available option. Whilst CIBSE TM59 offers the most widely used overheating assessment criteria for naturally-ventilated homes, the criteria have not been rigorously tested against real-world observations made beyond temperate regions of the UK. With an aim to examine the applicability of the CIBSE TM59 overheating criteria to subtropical residential contexts, statistical analysis was performed on thermal comfort field data collected from 162 dwellings in Australia. Our dataset consisted of indoor temperature observations recorded in living and sleeping spaces across the two-year monitoring period, accompanied by householders' subjective evaluation of thermal comfort (both daytime and nocturnal) and sleep quality. The results of our analysis identified a significant gap between the overheating assessment criteria and actual householders' experience of thermal conditions in their homes. Whilst most of our sample dwellings were deemed ‘overheated’ according to CIBSE TM59, approx. 80 % of daytime and nocturnal thermal sensations collected from the householders indicated they were comfortable. Especially in bedrooms, CIBSE's static 26 °C upper temperature threshold was found to be too stringent to be applicable to naturally-ventilated homes in subtropical regions of Australia. Our analysis demonstrated that sleep thermal comfort and sleep quality remained unaffected well beyond CIBSE's 26 °C limit. This study calls for further research in diverse climatic, housing, demographic and cultural contexts.

Vibrational comfort improvement for a passenger car driver seat

Abstract This paper presents an experimental study aimed at providing new insights into passenger vehicle driver seat vibration. The study investigates the effects of various driver seat components on the damping coefficient. By employing a design for six sigma method, an optimized seating solution is proposed to enhance seat comfort levels. The control factors used in this study include seat cushion upholstery, topper foam, cushion foam, pulmaflex, torsion bar and seat structure. Seat position, foam thickness and body mass are considered as potential noise factors. Subjective evaluation of seat comfort is conducted using the SAE J 1441-2016, comparing three different passenger car driver seats. The seats are disassembled from the vehicles and mounted on a six-degree-of-freedom shaker test bench. Vertical vibration data are filtered, and transmissibility curves are experimentally obtained from the seat rail to the seat cushion via a pad. Uncomfortable seat prototypes are then manufactured, and alternative configurations are tested on the shaker. The objective and subjective evaluations of the seat prototypes reveal that lower foam hardness, higher foam density, and flexible upholstery contribute to improved comfort levels. Moreover, the prototype seat with optimum parameters receives a subjective evaluation SAE score of +0.75, indicating an enhancement in comfort.

Quantification and Pictorial Expression of Driving Status Domain Boundaries for Autonomous Vehicles in LTAP/OD Scenarios

The ability of advanced driver assistance systems (ADAS) and autonomous vehicles to make human-like decisions can be enhanced by providing more detailed information about vehicles and in-vehicle users’ states. In this paper, the driving status domains of vehicles in left turn across path/opposite direction (LTAP/OD) scenarios are subdivided into comfort, discomfort, extreme, and crash, and the boundaries of each status domain are quantified and visualized. First, real unprotected left turn road segments are chosen for the actual vehicle testing. Subjective passenger comfort evaluation results and objective motion state data of vehicles during the experiment are organized and analyzed by statistics. In addition, the pictorials are plotted to determine the comfort and extreme status domain boundaries based on motion state parameters. Second, based on the unprotected left turn kinematic analysis and modeling, as well as a skilled driver risk perception and operational model, the Safe Collision Plots (SCP) of conflicting vehicles in LTAP/OD scenarios are quantified and expressed as pictorial examples. By combining objective motion parameters and passenger experience, intuitively quantifying each driving status domain of vehicles can provide more fine-grained information for the design parameters of ADAS and autonomous vehicles and increase public trust and acceptance of them.

The Impact of Sound Pressure Level, Loudness, Roughness, Sharpness, Articulation Index, Hand Vibration, and Seat Vibration on Subjective Comfort Perception of Tractor Drivers

Long-term exposure to high levels of vibration and noise can have detrimental effects on the health of tractor drivers. This study aimed to evaluate the subjective comfort experienced by drivers operating large-horsepower tractors. A total of 10 tractors sourced from 5 different manufacturers were subjected to testing. The assessment encompassed three operational conditions, namely, idle, maximum torque, and rated power. Objective measurements, including A-weighted sound pressure level (A-SPL), loudness, sharpness, roughness, articulation index (AI), hand vibration, and seat vibration, were collected. Additionally, subjective comfort evaluations were carried out using a paired comparison test. To predict the subjective comfort of tractor drivers, a novel prediction model was developed by employing a simulated annealing (SA) algorithm to optimize a backpropagation neural network (BPNN). The model successfully achieved accurate predictions of subjective comfort, yielding a maximum prediction error of 4.4%. The study findings revealed that vibration had a more pronounced impact on driver comfort in environments with lower-amplitude noise, whereas high-decibel noise exerted a masking effect on vibration-induced discomfort. In conclusion, the SA-BPNN model, utilizing A-SPL, loudness, sharpness, roughness, AI, hand vibration, and seat vibration as objective parameters, effectively predicted the subjective comfort of tractor drivers. This discovery holds significant implications for tractor manufacturers, who can employ the model to optimize the design of tractor cabs and enhance driver comfort.

A study on daylighting metrics related to the subjective evaluation of daylight and visual comfort of students in China

Uneven daylighting distribution in classrooms is a common issue in many countries, despite meeting the standard daylighting factor (DF). The issue has been particularly acute in China. With the development of dynamic daylighting metrics, they have been incorporated into daylighting standards in various countries. The introduction of dynamic daylighting metrics in China is an opportunity to improve the classroom lighting environment, considering that the Chinese regulations have not been updated for a long time. However, there is a dearth of research investigating the validity of dynamic daylighting metrics in Chinese school buildings. Therefore, a correlation analysis of dynamic daylighting metrics and students' subjective evaluation has been carried out. This one-year study included field surveys and illuminance measurements collected in 18 classrooms in a Chinese school; the dynamic and static daylighting metrics of these classrooms were simulated. The spatial daylight autonomy (sDA) at 450 lx for 50% of annual hours (sDA450/50%; a dynamic metric) and the proportion of area with an illuminance (Ep) > 300 lx (a static metric) were highly correlated with student evaluations. Additionally, sDA450/50% ≥50% was preferred by student evaluations. Annual sunlight exposure (ASE) was not correlated with student evaluations in north-facing classrooms in the Guangzhou area. However, a correlation was found between perceived blackboard glare and the percentage of space where disability glare probability (DGP) exceeded a threshold of 0.35 for>5% of the usage time (sDGPexceed). Consequently, sDA450/50%≥50% is a recommended metric for China’s school-building daylight standards, while sDA250/50% ≥75% can be used simultaneously to improve the effective daylighting area of classrooms.

Comparing children's, teenagers' and young adults' subjective responses to myopia control contact lenses.

Myopia control (MC) studies in children link efficacy with subjective performance. There is little MC research in teenagers and young adults. This study compared subjective experience of MC contact lenses in different age groups. Data were retrospectively reviewed from two double-masked, bilateral wear, crossover contact lens clinical trials (myopia -0.75D to -3.50D and <1.00 DC; 9-35 years). Participants wore two novel lenses (MC lenses with relative peripheral plus [+1.50D and +2.50D]) and a single-vision (SV) control lens (Clariti® 1day) for 1 week each. All lenses were made from Somofilcon A material. Data collected included visual acuity (VA), wearing time, subjective ratings of comfort, distance and near vision clarity and overall vision. Generalised estimating equations with subject random intercepts and identity link functions were used in the analysis. A total of 31 participants (10 children, 11 teenagers and 10 adults) were included, with no difference between the age groups for VA with the dispensed lenses (p > 0.05). All groups could discriminate between the SV and MC lenses for vision (distance, near and overall) after 1 week (p < 0.05). There was no difference between groups for comfort or distance and near vision. Children rated the overall vision quality higher than teenagers and adults for both SV and MC lenses (p < 0.05), but there was no difference relative to the SV lens between groups (p > 0.50). Daily wear time was lowest for children for all lens types (all p < 0.02). Wear time was positively associated with ratings of overall vision quality for children and young adults (both p < 0.05). All age groups rated SV lenses higher than MC lenses. Subjective ratings of MC lenses appear similar between age groups relative to SV lenses. Wear time was lowest in children and was correlated with overall vision quality ratings in children and young adults.

Sporters' visual comfort assessment in gymnasium based on subjective evaluation & objective physiological response

Visual comfort is affected by the light environment of interior spaces. However, relatively few studies have combined subjective and objective indicators of visual comfort in the assessment of indoor sport facilities. Thus, the purpose of this was to determine the factors influencing visual comfort and establish corresponding thresholds by combining subjective evaluation, objective physiological indicators, and photometric light environment assessment. The experiment was conducted at a university gymnasium in Harbin, located in the northeast of China, during summer, autumn, and winter. The visual comfort of the participants was assessed via subjective evaluation via questionnaires, and objective physiological indicators were recorded using biosensors. Additionally, high-dynamic-range images were used to assess the light environment. Subjective evaluation revealed that visual comfort was affected by the glare intensity, target clarity, and emotional state. Objective physiological indicators showed that emotional arousal and alertness were higher in autumn and winter than in summer. Furthermore, the physiological indicators and subjective evaluation of visual comfort were highly consistent with each other. In summer, acceptable ranges of the luminance ratio of the window area to the field of view were less than 5 and greater than 10, and comfortable ranges were less than 3 and greater than 12. In winter, the upper acceptable and comfortable thresholds were 42 and 13, respectively. This study provides a reference point for optimizing gymnasium light environment design.

Effectiveness of Shock-Absorbing Insole for High-Heeled Shoes on Gait: Randomized Controlled Trials.

This study was carried out to identify the influence of a shock-absorbing insole, developed by the author for use with high-heeled shoes, on walking. The research design included single-blind randomized parallel groups; namely, a group of 26 participants who wore the shock-absorbing insoles and another group of 26 participants who did not wear the insoles, both carried out walking while wearing 7 cm high-heels. During walking, plantar pressure analysis (via in-shoe plantar pressure measurements), surface electrode electromyography (surface EMG), gait analysis, subjective comfort evaluation, and functional movement (functional mobility) analysis were carried out. In order to compare the two groups, statistical verification (paired t-test) was performed. Wearing the shock-absorbing insole with the high-heeled shoes improved posture stability during walking, as well as increasing the walking speed. In addition, the heel pressure, the pressure of the front foot at the inner side, and the shock ability were decreased. For these reasons, the wearers reported higher comfort. Changes in the muscle activities of the tibialis anterior muscle (TA) and the gastrocnemius muscle (GA) heightened the stability of the ankle joints. Overall, the proposed shock-absorbing insole for use with high-heeled shoes improved the postural stability when walking, as well as improving the distribution of pressure on the soles. A decrease in the diverse side-effects of wearing high-heeled shoes can thus be expected.

A Study of a Ride Comfort Control System for Ultra-Compact Vehicles Using Biometric Information

We investigated whether there is a correlation between the comfort felt by occupants and the comfort estimated from biological information obtained by experiments to improve the ride quality of an ultra-compact vehicle. A single frequency in the vertical direction can help to estimate occupant comfort. However, we hypothesized that the study of a single frequency was insufficient. We oscillated the occupants with vibrations containing multiple vibration frequencies and obtained biometric information. The vibration frequency was set based on the difference in ride quality felt by humans. Biometric information was obtained using a cerebral hemodynamic meter and electrocardiogram. Acquiring multiple types of biometric information helps to more accurately estimate the psychological state. After the experiment, we obtained a subjective evaluation of comfort against vibrations using the visual analog scale (VAS). The biometric information obtained by the experiment was cluster-analyzed, and experimental participants with similar characteristics of the biometric information were grouped. Multiple regression analysis was performed based on the values of the typical biometric information of the cluster. Comfort was estimated from biometric information using multiple regression analysis. A correlation was confirmed between measured and estimated VAS scores.

Numerical and Experimental Investigation on Symmetrical Cross Jet of Localized Air Conditioning System with Thermoelectric Cooling Devices in Commercial Vehicles

The localized air conditioning (LAC) system focuses on the micro environment around the human body, avoiding the energy waste of cooling the entire compartment. The application of small and flexible thermoelectric cooling devices (TEDs) provides more possibilities for automotive LAC, but also increase the collision and convergence of airflow at the same time. Therefore, the impact of symmetrical cross jet collision on the thermal environment in the cab has been analyzed through numerical simulation and experimental methods. The results show that the velocity and temperature of the dual jets in the merging zone have better uniformity. The human body also has better comfort under the environment constructed by the jets in this special state. The optimized jet collision angle is given to match the distance between the different air outlets and the human body in the thermal environment constructed by the localized air conditioner to achieve the best cooling effect. Real vehicle experiments and subjective evaluation of human comfort have been done to verify the cooling effect of the localized air conditioning system.

EFFECTS OF A PROPHYLACTIC KNEE SLEEVE ON THE ANTERIOR CRUCIATE LIGAMENT AND LOWER EXTREMITY BIOMECHANICS: AN EXAMINATION USING MUSCULOSKELETAL SIMULATION

The current study aimed using a two-experiment musculoskeletal simulation-based approach, measuring anterior cruciate ligament (ACL) biomechanics, knee joint kinematics, and lower extremity joint loading to examine the effects of both a prophylactic knee sleeve on (1) a sport-specific change of direction movement in female footballers and (2) a single leg landing in male footballers. Experiment 1 examined 12 female university first team level footballers (age [Formula: see text] years, height [Formula: see text][Formula: see text]m, body mass [Formula: see text][Formula: see text]kg) undertaking a [Formula: see text] cutting movement in sleeve and no-sleeve conditions. Experiment 2 examined 10 male university first team level footballers (age [Formula: see text] years, height [Formula: see text][Formula: see text]m, body mass [Formula: see text][Formula: see text]kg) undertaking a single leg drop jump landing in sleeve and no-sleeve conditions. In each experiment, data was collected in a biomechanics laboratory and three-dimensional (3D) motion capture and ground reaction force (GRF) information was collected. 3D kinematics, 3D knee kinetics, and ACL ligament forces/strains were measured using musculoskeletal simulation, and participants were also asked to subjectively rate the knee sleeve in terms of both comfort and stability. Experiment 1 showed that the sleeve condition was associated with greater ACL strain ([Formula: see text]% and no-[Formula: see text]%) and forces ([Formula: see text] BW and no-[Formula: see text] BW). In addition, the brace condition also enhanced lateral compressive tibiofemoral ([Formula: see text] BW and no-[Formula: see text] BW) and total compressive tibiofemoral force ([Formula: see text] BW and no-[Formula: see text] BW). Finally, for the subjective ratings, participants indicated that the knee sleeve significantly improved perceived comfort and stability. Experiment 2 did not reveal any statistical differences between knee sleeve and no-sleeve conditions nor any effects of the knee sleeve on subjective ratings of comfort or stability. Therefore, the findings from the current investigation suggest that the prophylactic knee sleeve examined in the current investigation does not appear to reduce the biomechanical parameters linked to the aetiology of knee pathologies in male/female footballers.

Exploring the factors which impact overall satisfaction with single vision contact lenses

PurposeTo explore the impact of subjective factors (lens handling, comfort and vision) on overall single vision contact lens satisfaction. MethodsCorrelation analysis of a prospective, randomised, double-masked, bilateral crossover study involving 55 adapted lens wearers fitted with somofilcon A (SiHy) (clariti® 1 day, CooperVision) and etafilcon A (Hy) (1 DAY ACUVUE® MOIST, Johnson & Johnson Vision) was conducted. Subjective ratings of lens handling, comfort and vision collected after 1 week of lens wear for each lens type were correlated with overall satisfaction. Data were analysed by combining data for both lens types and also for each lens separately. ResultsFor the combined analysis, significant correlations (p < 0.01) were found between subjective ratings of overall satisfaction and ratings of handing for application (r = 0.64), handling for removal (r = 0.50), comfort upon application (r = 0.59), comfort at end of day (r = 0.61), overall satisfaction with comfort (r = 0.88) and overall satisfaction with vision (r = 0.64).Correlation analysis of the per lens data showed that lens specific correlations of overall satisfaction with handling for lens application varied greatly with lens material (SiHy: r = 0.26, p = 0.05 vs Hy: r = 0.72, p < 0.01). Correlation strength of comfort upon application/at end of day with overall satisfaction also varied with lens material (Application: SiHy: r = 0.40 vs Hy: r = 0.61; End of day: SiHy: r = 0.76 vs Hy: r = 0.58; all p ≤ 0.01). ConclusionOverall satisfaction was significantly correlated with the specific subjective evaluations of handling, vision and comfort. Correlations of overall satisfaction and ease of handling for each lens type suggest that, for habitual contact lens wearers, dissatisfaction with handling at the time of lens application can play a major role in overall dissatisfaction with a lens. Handling for application had a similar correlation (r) value as vision, suggesting that handling for application should not be underestimated when considering overall patient satisfaction.

A Review of the Use of Wearables in Indoor Environmental Quality Studies and an Evaluation of Data Accessibility from a Wearable Device

An understanding of indoor environmental quality (IEQ) and its effects on occupant well-being can inform building system design and operation. The use of wearables in field studies to collect subjective and objective health performance indicators (HPIs) from a large number of occupants could deliver important improvements in IEQ. To facilitate the use of wearables in IEQ studies, there is a need to identify which HPIs should be collected and to evaluate data accessibility from these devices. To address this issue, a literature review of previous IEQ studies was conducted to identify relationships between different IEQ factors and HPIs, with a focus on HPIs that were collected using wearables. A preliminary assessment of data accessibility from a selected wearable device (Fitbit Versa 2) was performed and documented. The review suggested the need to further investigate and collect sleep quality parameters, heart rate, stress response, as well as subjective ratings of comfort using wearables. The data accessibility assessment revealed issues related to missing data points and data resolution from the examined device. A set of recommendations is outlined to inform future studies.

Performance on heating human body of an optimised radiant-convective combined personal electric heater

In this study, we developed an optimised radiant-convective combined personal electric heater, considering the limitations of traditional personal heaters that heat the human body through heat transfer of single convection or single radiation. Based on human participant experiments in simulated environments, the heating performance of the optimised personal heater on the human body was tested. The initial indoor air temperature in the experimental room was set to 14 °C. Twenty-four healthy young college students, including 12 males and females, were recruited as participants. They were required to experience three types of personal heaters in a sitting position: optimised combined personal heater (PHSR + C), convective personal heater (PHSC), and radiant personal heater (PHSR). During the 80-min-long experiment, their subjective ratings of thermal comfort, perceived air quality, sweating sensation, air movement sensation, and sick building syndrome were collected using questionnaires, and physiological parameters, such as skin temperature, tympanic temperature, and heart rate, were measured. The obtained results showed that, compared with PHSC and PHSR, PHSR + C increased the overall thermal sensation more rapidly (0.083 scale/min), and maintained the human body at a warmer condition. Moreover, when using PHSR + C, mean skin temperature and its change rate, and the thermal sensation vote of all local body parts were higher. The results indicate that the heating performance of this newly developed combined personal heater surpassed that of the two traditional types. Moreover, compared to using PHSC and PHSR, over 27% of the energy consumption was saved using PHSR + C.

Thermal response test analysis of adults and preschoolers under radiant floor heating environment in a hot-summer and cold-winter area

The subjective and objective thermal comfort evaluations of adults and preschoolers in radiant floor heating rooms in a hot-summer and cold-winter area are tested in this article, and the thermal response of the two groups of subjects are analysed using a differential analysis method. The thermal response characteristics of subjects wearing winter clothing with a thermal resistance of 1.02 clo and maintaining a sitting posture were studied at different locations in the office building and different indoor temperatures by combining the characteristics of hot-summer and cold-winter area and the characteristics of office buildings. The results show that when the indoor temperature varies, there was a significant difference in the local skin temperature of the calf of the two groups of subjects (P&lt;0.05). Preschoolers have a more intense overall thermal sensation vote than adults due to the difference in metabolic rate. Different groups of people’s overall thermal sensation vote were linearly correlated. The overall thermal sensation vote of the subjects is linearly related to the indoor operative temperature. The PMV-PPD model is used as the thermal sensation evaluation standard, and there is a considerable difference between the subjective appraisal of preschoolers’ thermal sensations. The PMV-PPD model is not suitable for preschoolers.

Quantification of physical stress experienced by obstetrics and gynecology sonographers: A comparative study of two ultrasound devices

This study aims to quantify the stresses of sonographers using two different ultrasound devices, one of conventional and one of ergonomic design. A total of 20 obstetricians and gynecologists participated in this study, and two types of tasks (scanning and positioning) were evaluated while using the two different devices. To quantify workload, four dependent variables (muscle activity, estimated grip force, subjective comfort rating, and task time) were measured. The muscular activity required while using the conventional device was 14.4% MVC (Maximum voluntary contraction) for the scanning task, which was significantly higher than that of the ergonomic device. The subjective comfort rating for the conventional design was lower than that of the ergonomic design. For the positioning task, the ergonomic device (33.2% MVC) resulted in significantly higher muscle activity in the extensor digitorum (ED) and flexor digitorum superficialis (FDS) than the conventional design (22.2% MVC), whereas the deltoid muscle showed significantly lower activity than in users of conventional design (4.5% MVC). Ergonomically-designed ultrasound devices improve ease of moving and the probe's supporters, reduce physical load and increase ease of use for sonographers. Our results may be used as guidelines for usability testing of ultrasound devices.

차량용 공기 순환 장치가 후석 승객의 온열 쾌적성에 미치는 영향에 관한 연구

Recently, automotive industry in Southeast Asia and India has enlarged and lifestyle has been changed, with time spending in an automotive showing a gradual increase. Accordingly, thermal comfort that passengers feel inside the cabin of an automotive is more important than other region. Current air-conditioning system is dependent on the cool-down performance of an HVAC located inside the front instrument panel that supplies cold air from the front cabin to the rear cabin. Therefore, front seat passengers and rear seat passengers can feel thermal comfort quite differently because of solar radiation through windows, air flow velocities, and blowing air path in the cabin. In this study, to increase thermal comfort for rear passengers, especially those in 2nd row and 3rd row seats, an air-circulator was developed. The air-circulator was subjected to computational fluid analysis to find the appropriate airflow volume, air distribution rate, and air direction for passengers in 2nd row and 3rd row seats. Air-conditioning system cool-down performance, PMV, and subjective evaluation of thermal comfort of vehicle experiments were also carried out. As the result, roof top mounted air-circulator was optimized by computational analysis and experimental study. It was a quite good solution for improving cabin thermal comfort for passengers in 2nd row and 3rd row seats with cost effectiveness and a compact package.