Passenger thermal comfort and behavior: a field investigation in commercial aircraft cabins

A new method to identifying optimal adjustment strategy when the car cockpit is uncomfortable: optimal state distance method

With the rapid development of the automobile industry, the comfort of the cockpit has become the standard for judging the quality of the car. People have also put forward higher requirements for cockpit comfort. In the process of driving, the cockpit environment will constantly change, and the comfort will also change. When the comprehensive comfort level of the cockpit decreases and the occupants feel uncomfortable, the cockpit comfort should be adjusted. In this article, a cockpit comfort evaluation model is established to realize the evaluation of cockpit comfort. In addition, we elaborate the theory of optimal state distance, where the numerical magnitude of the optimal state distance is used to reflect the extent to which an indicator deviates from its optimal state. Also, a cockpit optimal adjustment strategy identification model is established based on the theory, which can obtain the optimal adjustment strategy in a certain cockpit operating environment, facilitate the timely adjustment of the corresponding actuator, and realize the dynamic monitoring and adjustment of cockpit comfort. This project provides a reference direction for cockpit comfort adjustment, which is of great significance for future research and development of automotive cockpit comfort.

Cabin aircraft comfort evaluation over high fidelity simulated flight

The primary purpose of this paper is to investigate the possibility of using a Full Flight Simulator (FFS) as an experimental setup for passengers' comfort analysis. Results based on subjective measurements are thus presented to assess comfort levels experienced during a simulated flight. A preliminary investigation has been conducted on a sample of 125 candidates to gain insight into the elements influencing the comfort level perceived based on the participants' actual flight experience; this suggested that the seat configuration is of great importance. Then, the experiment carried out by means of the FFS have been conducted on a reduced sample of 20 candidates for economic and organizational reasons. The behaviour of the 65% of the candidates has been analysed in a seating configuration comparable to the seat of a business-class aircraft. While the experience of the remaining 35% has been studied in an economy-type seat arrangement. Although the main variable under consideration was the seat, several environmental parameters were also considered during the experimental tests to evaluate their effects on perceived comfort level. During each simulated flight, passengers have been subjected to different levels of light intensity, noise, temperature and vibration associated with the different flight phases. Subjective data were collected using a questionnaire concerning every parameter and submitted to the passengers for each flight phase. The aim of varying the environmental parameters inside the cabin was to look for a relation between the subjective comfort level and each comfort parameter. In addition to perceived comfort based on the questionnaire, statistical analysis with parametric and non parametric tests revealed significant effects of environmental variables.

Recent progress on studies of airborne infectious disease transmission, air quality, and thermal comfort in the airliner cabin air environment

Airborne transmission of infectious diseases through air travel has become a major concern, especially during the COVID-19 pandemic. The flying public and crew members have long demanded better air quality and thermal comfort in commercial airliner cabins. This paper reviewed studies related to the airliner cabin air environment that have been published in scientific journals since 2000, to understand the state-of-the-art in cabin air environment design and the efforts made to improve this environment. In this critical review, this paper discusses the challenges and opportunities in studying the cabin air environment. The literature review concluded that current environmental control systems for airliner cabins have done little to stop the airborne transmission of infectious diseases. There were no reports of significant air quality problems in cabins, although passengers and crew members have complained of some health-related issues. The air temperature in cabins needs to be better controlled, and therefore, better thermal comfort models for airliners should be developed. Low humidity is a major complaint from passengers and crew members. Gaspers are used by passengers to adjust thermal comfort, but they do not improve air quality. Various personalized and displacement ventilation systems have been developed to improve air quality and thermal comfort. Air cleaning technologies need to be further developed. Good tools are available for designing a better cabin air environment.

Thermal Condition and Air Quality Investigation in Commercial Airliner Cabins

Cabin air quality and thermal conditions have a direct impact on passenger and flight crew’s health and comfort. In this study, in-cabin thermal environment and particulate matter (PM) exposures were investigated in four China domestic flights. The mean and standard deviation of the in-cabin carbon dioxide (CO2) concentrations in two tested flights are 1440 ± 111 ppm. The measured maximum in-cabin carbon monoxide (CO) concentration is 1.2 ppm, which is under the US Occupational Safety and Health Administration (OSHA) permissible exposure limit of 10 ppm. The tested relative humidity ranges from 13.8% to 67.0% with an average of 31.7%. The cabin pressure change rates at the end of the climbing stages and the beginning of the descending stages are close to 10 hPa·min−1, which might induce the uncomfortable feeling of passengers and crew members. PM mass concentrations were measured on four flights. The results show that PM concentrations decreased after the aircraft cabin door closed and were affected by severe turbulences. The highest in-cabin PM concentrations were observed in the oldest aircraft with an age of 13.2 years, and the waiting phase in this aircraft generated the highest exposures.

A modified turbulence model for simulating airflow aircraft cabin environment with mixed convection

The forced convection (air supply jet) and the natural convection (thermal plume of passenger) co-exist in an aircraft cabin simultaneously. Due to the notable difference of the Reynolds numbers for the two convection processes, the traditional RANS method can hardly simulate the forced/natural convection flows accurately at the same time. In addition, the large geometric ratio between the main air supply inlet and the whole cabin leads to difficulties in grid generation for the cabin space. An efficient computational model based on the standard k-e model is established to solve these problems. The coefficients in the dissipative equation are modified to compensate the enlarged numerical dissipation caused by coarse grid; meanwhile, the piecewise-defined turbulent viscosity is introduced to combine the forced and natural convection. The modified model is validated by available experimental results in a Boeing 737-200 mock-up. Furthermore, the unsteady characteristic of the aircraft cabin environment is obtained and analyzed. According to the frequency analysis, it turns out that the thermal plume is the main factor of the unsteady fluctuation in cabin.

ELECTRONIC SUPPLEMENTARY MATERIAL ESM

Supplementary material is available in the online version of this article at 10.1007/s12273-020-0609-2.

Field study of neutrality cabin temperature for Chinese passenger in economy class of civil aircraft

Cabin thermal comfort is an important factor for the competitiveness of civil aviation. It has become a hot topic in recent years. However, there are still no clear standards for the thermal comfort in the aircraft cabin. In this paper, the cabin thermal comfort of passengers in 30 flights was investigated. Both objective and subjective data were collected in order to obtain a neutrality cabin temperature, T_nc. The investigation shows that the distribution of Thermal Sensation Votes (TSVs) was approximately symmetric around the "Neutral" vote. The clothing insulation value of passengers, I_CLO, was affected by the outdoor mean new effective temperature of departure city, ET*. T_nc also changed with the outdoor ET*. According to this field surveys, a linear relationship is built between T_nc and ET* as an adaptive model for the civil aircraft cabin. This adaptive model can be used as a reference to control the cabin operative temperature around the passengers. In this way, the cabin thermal comfort requirement may be satisfied for most of the passengers.

Behavioural, physiological and psychological responses of passengers to the thermal environment of boarding a flight in winter

In practice, passengers actively respond to the thermal environment when they board an aircraft in winter, which is not considered in the current standards. In this study, the behavioural, physiological and psychological responses to the thermal environment were examined at 22 °C (with 68 subjects), 20 °C and 26 °C (with 32 subjects). The results showed that the three air temperature levels had significant effect on nozzle usage and clothing adjustment behaviours, surface skin temperature, and thermal sensation vote (TSV). The walking/waiting states prior to boarding the aircraft cabin had a significant effect on the proportion of jacket removal, TSV and thermal comfort vote. After 10 min in the aircraft cabin, the subjects maintained their comfort in a wider range of the thermal environment when the behavioural adjustments existed compared to when they did not. Thus, a suggestion was made for behavioural adjustments to be provided in aircraft cabins. Practitioner Summary: Experimental investigation of human responses was conducted in an aircraft cabin. Analysis showed that the subjects maintained their comfort in a wider range of the thermal environment when the behavioural adjustments existed compared to when they did not. Thus, a suggestion was made for behavioural adjustments to be provided in aircraft cabins.

Comfort, Energy Efficiency and Adoption of Personal Cooling Systems in Warm Environments: A Field Experimental Study

It is well known that personal cooling improves thermal comfort and save energy. This study aims to: (1) compare different personal cooling systems and (2) understand what influences users' willingness to adopt them. A series of experiments on several types of personal cooling systems, which included physical measurements, questionnaires and feedback, was conducted in a real office environment. The obtained results showed that personal cooling improved comfort of participants in warm environments. Then an improved index was proposed and used to compare different types of personal cooling systems in terms of comfort and energy efficiency simultaneously. According to the improved index, desk fans were highly energy-efficient, while the hybrid personal cooling (the combination of radiant cooling desk and desk fan) consumed more energy but showed advantages of extending the comfortable temperature range. Moreover, if personal cooling was free, most participants were willing to adopt it and the effectiveness was the main factor influencing their willingness, whereas if participants had to pay, they probably refused to adopt it due to the cost and the availability of conventional air conditioners. Thus, providing effective and free personal cooling systems should be regarded as a better way for its wider application.