Comfort In Cabin Research Articles

A Study of Flow Analysis Within a Tractor Cabin with the Goal of Determining the Best Vent Location and Glazing

This study aims to improve the thermal comfort inside a tractor cabin by determining the position of the air conditioner vent location. This is obtained by maintaining the cold air flow inside the cabin by means of the air conditioning vents and proper HVAC systems. The concept of glazing on windows with different materials was also used to improve the thermal comfort of the tractor cabin by reducing the thermal conductivity. Variations in thermal comfort were tested by creating a 3D model of the tractor cabin with different vent locations as per the model of actual tractor cabin with vent locations as follows, dashboard and side pillars. To evaluate the thermal comfort, the anticipated mean vote (PMV) and expected percentage of unsatisfied were utilized, and the temperature, air velocity, and humidity for calculating PMV were simulated. The temperature and PMV measurement sites were chosen based on the SAE J1503 temperature measuring positions. Using suitable data, CFD simulations were performed on commercial simulation software (STAR-CCM+). Based on the result of the analysis, it was observed that maximum thermal comfort was obtained by placing the air conditioner vent on the dashboard which helped in cooling the tractor cabin in less time than the other vent locations. Considering the correct air conditioner vent location together with the spectral solar radiation effect, the average cabin temperature was, which waslower than other vent locations. When exposed to hot temperature conditions, a vehicle's structure can absorb a large quantity of heat. 50-70 percent of this heat passes through the glazing and boosts the internal cabin air temperature as well as the temperature of the interior trim surfaces. When driving away, the air conditioning system must be capable of quickly eliminating this heat, allowing the occupants to return to a comfortable state in a reasonable amount of time. (124). We achieved optimum comfort and a desirable temperature range, we improved working conditions of the operator in a tractor. By using different glazing material, we aim to study and improve operator’s thermal comfort. A 3D based computational fluid dynamics (CFD) software will be used to analyze climate in the tractor vehicle cabin.

Investigation of the Impact of a Particle Foam Insulation on Airflow, Temperature Distribution, Pressure Profile and Frost Buildup on the Aircraft Structure

Aircraft insulation separates the thermally comfortable cabin interior environment from the extremely cold outside conditions. However, the fabrication and installation of the insulation in the aircraft is a labor-intensive task. Tailored, rigid particle foam parts could be a solution to speed up the installation process. The presented study investigates the feasibility of such a concept from a hygrothermal point of view. Due to the temperature difference between the cold air trapped between aircraft skin and insulation on one side and the warm cabin air on the other side, a buoyancy-induced pressure difference forms. This effect drives the warmer air through leakages in the insulation system towards the cold skin. Here, moisture contained in the air condenses on the cold surfaces, increasing the risk for uncontrolled dripping (“rain in the plane”) when it melts. Therefore, this study compares the condensate build-up of different installations of a rigid particle foam frame insulation with the classical glass fiber capstrip. Tests are hosted in the Fraunhofer Lining and Insulation Test Environment chamber. It is shown that careful installation of the particle foam frame insulation provides similar level of moisture protection as the current state of the art insulation, and that the condensate amount does not depend on the amount of airflow directly behind the sidewall.

Analytical and experimental investigation on heat transfer and flow parameters of Multichannel louvered fin cross flow heat exchanger using iterative LMTD and ∊-NTU method

Automotive Heat exchangers plays vital role by ensuring human comfort in cabin by maintaining optimum temperature and maintains operating temperature of Internal Combustion(IC) engine within permissible limits. In this work, iteration based mathematical model to solve for analytical thermo-hydraulic performance estimation of a typical heat exchanger is adopted with Log Mean Temperature Difference (LMTD) method by incorporating the variation in properties of fluids during each iteration, since the overall thermal resistance ratio between targeted & calculated Heat Rejection Rate (HRR) has to be converged to unity to solve for the actual thermal performance of the heat exchanger. This condition ensures convergence and there is no deviation between the two adjacent iterations in terms of HRR value. Additionally, the above condition ensures that deviation between analytical value calculated by Effectiveness-NTU (∊-NTU) method and experimental data will be reduced significantly due to the proposed iterative LMTD approach adopted in this work. Along with iterative LMTD methodology, ∊-NTU method is adopted for last iteration to cross-verify the obtained value of the HRR for same operating conditions. In order to evaluate heat transfer coefficients for air and coolant side, standard correlations are used from well-established and validated literature data. For coolant side pressure drop calculations, network solution methodology is adopted where fluid flow behavior in each segment of heat exchanger is studied in detail and analytical relationships are used to predict net pressure drop in entire heat exchanger. In our mathematical model, louvered fin effects on heat transfer is taken into account by adopting colburn approach and the geometrical effects of internal fins on flow channels is also included. Experimental validations tests are carried out to compare with the analytical results of HRR, Coolant Side Pressure Drop (CSPD) and Air Side Pressure Drop (ASPD) across heat exchanger. A good agreement is found between experimental and analytical results which validates the accuracy of present mathematical model and methodology, the maximum deviation for HRC is 4% on higher side, for CSPD and ASPD it is 15.4%,8.7% on higher side respectively.

Exploring Cruise Tourists’ Preferences and Satisfaction: The Case of Taiwan

In this study, the product attributes of cruise tours are distinguished into on-board activities, leisure space, cabin comfort, Michelin restaurant, and refund mechanism, and the multi-attribute utility model of cruise tours is constructed using the choice experiment (CE) method. Of the 575 questionnaires distributed, 439 were valid, with an effective recovery rate of 76.3%. The results revealed the following: (1) when cruisers travel, what they value the most is the quality of service on board, followed by the facilities on board; (2) passengers’ preferences for comfortable pool space and more activities on board are negatively significant, indicating that they do not prefer to add these amenities and experiences to the cruise ship; (3) passengers are willing to pay extra to upgrade the interior cabin to one with a view and to experience the Michelin restaurant; and (4) influenced by the COVID-19 pandemic, cruisers are more willing to manage their own health. Moreover, the pandemic does not reduce their willingness to travel by cruise.

Evaluation of waste heat recovery of electrical powertrain with electro-thermally coupled models for electric vehicle applications

The mile range of an electric vehicle (EV) may be reduced significantly in cold weather owing to the energy demand for meeting thermal comfort in the vehicle cabin, as waste heat from a combustion engine is not available for this purpose. Various heat pump-based heating, ventilation, and air conditioning (HVAC) systems can be employed to absorb the heat energy from the surroundings and/or the waste heat from the electrical powertrain to facilitate cabin thermal comfort, thereby extending the EV mile range. However, there is a lack of research on the electro-thermally coupled modelling and evaluation of the thermal performance of HVAC systems. This paper proposes electro-thermally coupled models for the electrical machine and inverter by modelling the key electromagnetic quantities as functions of the torque and speed based on offline parameter extraction from two-dimensional electromagnetic finite element analysis. The proposed electro-thermally coupled models, which are computationally efficient, are integrated into HVAC thermofluid simulation. Comparative studies of three heat pump-based HVAC architectures (conventional ambient heat only, waste heat only, and dual heat source) are performed using the proposed electro-thermally coupled models. The dual heat source HVAC architecture exhibits superior thermal performance over its counterparts in cold weather conditions.

Development of acoustic mufflers for cabin noise reduction in Orion spacecraft

Controlling cabin acoustic noise levels in the Crew Module (CM) of the Orion spacecraft is critical for adequate speech intelligibility, avoid fatigue, and prevent any possibility of temporary and permanent hearing loss to the crew. The primary source of cabin noise for the on-orbit phase of the mission is from the Environmental Control and Life Support System (ECLSS) which recycles and conditions breathing air and maintains cabin pressurization through its ducting network and components. Unfortunately, as a side effect, noise from the ECLSS fans propagates through theses ducts and emanate into the cabin habitable volume via the ECLSS inlet and outlets. To mitigate excessive duct-borne noise, two ECLSS mufflers have been designed to provide significant acoustic transmission loss (TL) so that the cabin noise requirements can be met. Each muffler is meant to be installed in the ducting of the ECLSS air inlet and outlet sides, respectively. Packaging constraints and tight volume requirements necessitated the mufflers to be of complex geometry and compatible with the bends of the ECLSS duct layout. To design and characterize the acoustic performance of the inlet and outlet mufflers, computational acoustic models were developed using the Finite Element Method (FEM) with software. Characterization of the acoustic material and perforations in the mufflers were addressed with poro-elastic theory. Once the mufflers were designed on paper and its TL predicted, prototypes of these mufflers were created using additive manufacturing. The muffler prototypes were subsequently tested for acoustic TL in the laboratory with various configurations of acoustic materials. Comparing the analytical predictions to the test performance yielded excellent correlation for acoustic TL and demonstrated significant broadband noise attenuation. The ECLSS mufflers are currently scheduled to be installed on the Artemis II CM of the Orion spacecraft and will provide significant cabin comfort to crew during the mission.

Aircraft interior acoustics - background noise contamination

Aircraft interior noise is an important factor to be considered for cabin comfort. In a cruising condition this noise source is mostly broadband in nature and is coming from the exterior, primarily the turbulent boundary layer (TBL) of the flow around the moving aircraft. Capturing this noise to a high frequency is critical for designing the sound packaging. Also, this becomes important in the design of public announcement (PA) system for the aircraft cabin, i.e. the correct placement of speakers. One of the metrics used for this acoustic design is speech transmission index. Deterministic techniques like finite or boundary element techniques for low frequencies and ray tracing method to reach higher frequencies are better suited for getting the narrow band responses. On the other hand, to characterize the background noise due to the TBL loads, statistical energy analysis (SEA) route is pursued. In this paper the authors combine different techniques to capture the background noise and use them with PA sources and eventually capture the sound perceived at points of interest. The articulation metrics are compared for different operating conditions of the aircraft. In the presentation attempts will be made to play the auralized sounds.

Prediction and Improvement of Aircraft Cabin Acoustics using Statistical Energy Analysis and Sound Quality Evaluation

Aircraft interior acoustic design is a key influencer for cabin comfort. An essential part of the design is optimization of acoustic insulation systems under weight restrictions to create a pleasant environment for human ear. Considering the complexity of aircraft geometry, noise sources, and transfer paths, computational prediction techniques become invaluable tools for increasing the accuracy in material selection while reducing design time and costs. In this study, a procedure that integrates sound quality evaluation with Statistical Energy Analysis (SEA) to design aircraft acoustic insulation systems is described. SEA is employed to predict the cabin sound pressure levels of a narrow body aircraft insulated with sound absorption and vibration damping materials. Aircraft cabin including under-floor sections is modelled based on 3D airframe and VIP style interior design and the model is validated with flight test data. Transfer functions obtained from SEA model for selected transfer paths are utilized to filter the noise signal recorded with a binaural recording system during flight. Sound quality metrics are computed in order to map perceptive response. An iterative process is introduced to improve acoustic design by investigating the effects of different sound insulation systems and room absorption values on noise levels and sound quality metrics.

Effect of Personal Space Invasion on Passenger Comfort and Comfort Design of an Aircraft Cabin

Passenger comfort is becoming an important issue with the recent increase in air travel. A common cause of passenger discomfort and distress is the invasion of the passenger’s personal space. This paper presents the results of two studies addressing the environmental psychological characteristics of passengers during personal space invasion (PSI) and how PSI affects cabin comfort design. In study 1, our survey shows that PSI has different effects on the comfort of passengers with different genders, ages, education levels, and interpersonal relationships. From these survey data, we extracted 14 factors of PSI. In study 2, a Decision-Making Trial and Evaluation Laboratory (DEMATEL) model was established, with passenger comfort as the target layer, to determine the interrelation between 14 PSI factors. The causal relationships between the 14 factors were visualized by a causal diagram. We established a priority ranking of the 14 aircraft interior design indexes based on the corresponding relationships between the indexes and PSI factors. The findings of this study contribute to the understanding of how PSI impacts passenger comfort and offer strategies to improve the comfort design of aircraft cabins.

Analysis of an integrated thermal management system with a heat-pump in a fuel cell vehicle

Fuel cell vehicles (FCVs) are becoming increasingly popular because they are both environmentally friendly and energy efficient. However, because no waste heat from the internal combustion engine can be used, the additional electricity needed to heat the cabin in cold weather increases the energy consumption substantially. This also lowers both the fuel economics and driving range. The required additional heating is typically done with a positive temperature coefficient (PTC) electric heater. To overcome the associated performance problem, a novel vehicle-integrated thermal management system (VTMS) with a heat-pump system is developed and investigated in this study. Using a simulation, the performance of the VTMS is investigated with respect to cooling performance, heating performance, and heating energy consumption for several different heat sources. For four different driving cycles, the equivalent hydrogen consumption (EHC) is highest when the PTC heater is used. The heat-pump system, which uses waste heat generated by a proton exchange membrane fuel cell, shows the lowest EHC. The results reveal that the use of a heat-pump heating system with waste heat can reduce hydrogen consumption by ∼14.6%, 6.5%, 16.9%, and 16.7% compared to PTC heating. Furthermore, the driving ranges increased by 17.2, 6.8, 20.3, and 12.6 km per 100 km, respectively. The VTMS, thanks to its ability to reduce energy consumption effectively, makes it possible to improve the thermal comfort in the vehicle cabin, which is especially useful for the commercialization of FCVs.

Enhancing aircraft cabin comfort to compete with high‐speed trains: A survey in China

AbstractTo improve the competitiveness of air transport, this study proposed a method for devising a differentiated comfort enhancement strategy and compared the comfort of aircraft and high‐speed trains (HST). Structural equation modeling (SEM) was used to analyze the similarities and differences in the factors influencing comfort in aircraft cabins and HST compartments. The results showed that comfort in wide‐body aircraft cabins was mainly influenced by “food & beverage” and “personal in‐flight entertainment” (personal IFE), whereas comfort in narrow‐body aircraft and HSTs was mainly influenced by the “passenger interface.” The results also showed no significant difference in the overall comfort evaluation of the passenger interface between narrow‐body aircraft and HSTs. Furthermore, aircraft passenger ratings were significantly lower than those of HST passengers with regard to “spaciousness,” “seat comfort,” and “seat and cabin and compartment aesthetics.” The study results suggest that given competition from HSTs, airlines should use different comfort enhancement strategies for wide‐body and narrow‐body aircraft cabins.

A method identifying key optimisation points for aircraft seat comfort

Seating is the overriding factor influencing aircraft cabin comfort. To efficiently enhance seat comfort, this paper proposes a method to identify key optimisation points for seat comfort. Seat discomfort indicators are recognised based on a comparison of perceived performance with expectation. Confirmatory factor analysis is used to explore the latent variables of discomfort indicators, and a structural model was used to analyse correlations between latent variables. Finally, the most important latent variable influencing seat comfort was clarified. Analysis results of survey data from narrow-body aircraft show that seat discomfort indicators centre on the physical performance of the seat and include four latent variables: support performance, personal space, contact surface features, and safety and stability. Support performance determines body posture while travelling and is the overriding latent variable influencing seat comfort. This research establishes aircraft seat discomfort indicators, latent variables formed through the mutual linkage of discomfort indicators, and the structural relations between latent variables. The results can assist in the formulation of comfort optimisation procedures for aircraft seats. Practitioner summary: A method identifying the key points of aircraft seat comfort optimisation was proposed, which includes three steps: recognising discomfort indicators, exploring the relationship between discomfort indicators, and confirming the most important variable influencing seat comfort. Results provide guidance for aircraft seat optimisation. Abbreviations: SEM: structural equation modelling; EFA: exploratory factor analysis; CFA: confirmatory factor analysis; PA-OV: path analysis with observed variables; CR: construct reliability; AVE: average variance extracted; CMIN: likelihood-ratio chi-square; DF: degrees of freedom; GFI: goodness-of –fit index; AGFI: adjusted goodness-of –fit index; RMSEA: root mean square error of approximation; NNFI: non-normed fit index; RFI: relative fit index; CFI: comparative fit index; CN: critical N

Effect of scent on comfort of aircraft passengers.

BACKGROUND:Scents may influence the perceived comfort of an environment. There are only a few studies conducted on the relationship between scent and comfort in aircraft cabin.OBJECTIVES:The goal of this research is to explore whether relationships between scents and perceived comfort can be found for passengers in an aircraft cabin.METHODS: 276 participants joined an experiment in a Boeing 737 fuselage. The participants were divided into nine groups and each joined a session for 60 minutes with the exposure to different scents. The effect of the odor was measured by a set of questionnaires at the beginning and at the end of the session. Results of questionnaires were analyzed regarding the effects on the completion time, of the type of scents, of the intensity of the scent and on gender.RESULTS:Significant differences were found at the beginning and at the end of the experiment regarding comfort and emotion, but sometimes no relations could be established. The influence of different scents on comfort/discomfort varied and changed over time. However, in all scenarios, participant’ scores on emotion decreased. Additionally, the added scents influenced the linearity between the changes in comfort and discomfort.CONCLUSIONS:Smell could influence the perceived comfort/discomfort of aircraft passengers over time, and different types of smells have different effects on passengers. The preferences on scents are diverse, which highlights the need for personalization in aircraft cabin design.

Evaluation of heating efficiency and thermal comfort in special purpose vehicle cabins

The paper presents the integrated application of two methods during testing HVAC system efficiency in the cabins of HUMMER ?1151A1 and OAR 1RL-128D off-road vehicles. Spatial measurements of change in air temperature per time have been performed at three vertical levels (head, knees, and feet) of the driver and passengers, which totals to 15 measuring points per vehicle. The main goal of testing was to evaluate accurately the efficiency of heating and cooling in relation time interval required to attain a designed temperature of comfort in the vehicle cabin, on condition that the difference in ambient temperature levels does not exceed 10?C. With a view to more efficient evaluation of thermal comfort in vehicle cabins, the testing was performed also of predicted mean vote and predicted percentage of dissatisfied indices. Standard thermal comfort surveys ask subjects about their thermal sensation on a seven-point scale from cold (?3) to hot (+3). This research is carried out according to the methods based on ISO 7730, ASHRAE 55, and SORS 8419 standards.

Assessment method for civil aircraft cabin comfort: Contributing factors, dissatisfaction indicators, and degrees of influence

Civil aircraft cabin comfort is a significant consideration for travelers when selecting an airline. Based on questionnaires, this study developed an assessment method that identified the indicators of cabin-comfort dissatisfaction and determined the degrees of dissatisfaction. Questionnaires were distributed to passengers traveling on Chinese airlines, and the data were processed using an assessment model. Five factors comprising 36 total indicators were found to affect cabin comfort at different levels; the degree of dissatisfaction reflected the level of influence. Based on responses to open-ended questions in the survey and the identified degrees of dissatisfaction, the indicators were sorted into three levels: significantly affect comfort, generally affect comfort, and slightly affect comfort. This hierarchical division helps clarify which indicators should be prioritized for improvement. These research findings can help establish strategies to improve cabin comfort in civil aircraft and other forms of public transport.

Optimisation of Direct Battery Thermal Management for EVs Operating in Low-Temperature Climates

Electric vehicles (EVs) experience a range reduction at low temperatures caused by the impact of cabin heating and a reduction in lithium ion performance. Heat pump equipped vehicles have been shown to reduce heating ventilation and air conditioning (HVAC) consumption and improve low ambient temperature range. Heating the electric battery, to improve its low temperature performance, leads to a reduction in heat availability for the cabin. In this paper, dynamic programming is used to find the optimal battery heating trajectory which can optimise the vehicle’s control for either cabin comfort or battery performance and, therefore, range. Using the strategy proposed in this research, a 6.2% increase in range compared to no battery heating and 5.5% increase in thermal comfort compared to full battery heating was achieved at an ambient temperature at −7 °C.

Comfort Evaluation of an Aircraft Cabin System Employing a Hybrid Model

Comfort is becoming one of the most important principles in the process of design and evaluation of civil aircraft cabins. However, the comprehensive quantitative evaluation of comfort in an aircraft cabin is a complicated issue because of the subjectivity of comfort perception and a large number of factors involved in the whole complex cabin system. A hybrid model combined with the Decision Making Trial and Evaluation Laboratory (DEMATEL) method and fuzzy comprehensive evaluation is proposed, which considers both the interrelation between the criteria and the fuzziness of subjective comfort perception concurrently. The result of the empirical study from the questionnaire survey in flight was consistent with that of the hybrid model. The proposed model is effective. It could provide a more reasonable priority to improve comfort in the aircraft cabin. According to the measured results of the cabin environment, the cabin facilities and layout, seats and service, the specific differences between the criteria can be displayed clearly, which is helpful to improve the cabin comfort level.

Improving Cabin Comfort

Flight comfort expectations pose new challenges for acoustic development teams

Experimental study on dynamic thermal environment of passenger compartment based on thermal evaluation indexes.

In this article, the thermal environment and the human thermal comfort of car cabin under different driving states in summer were studied experimentally. The weighted predictive mean vote model and the weighted equivalent temperature model were used for calculation and compared with the experimental values. The experimental results show that the air temperature and relative humidity distribution in cabin are affected by the space position and driving state. The temperature of the cabin seat, which is affected by solar radiation and crew, in the heating stage is slightly higher than the air temperature, while the cooling rate in the cooling stage is much lower than the air temperature. The predictive mean vote model and the equivalent temperature model are basically consistent with the actual thermal comfort of human body under the idle and driving conditions with the change of time. The prediction accuracy of the two models under the idle condition is higher than that under the driving condition, and the overall prediction accuracy of the equivalent temperature model is higher than that of the predictive mean vote model.

Fixing a comfort cabin level in modern mining excavators

Foreign policy events of recent years, expressed in the adoption of sanctions, along with the global economic crisis, have identified the need for import substitution in Russian industry. The issue of import substitution in the mining industry is strategically important, because it determines the vector of development of the Russian economy. Therefore, in order to increase mineral extraction capacities, it is necessary to re-equip the parks with new-generation modern excavators and modernize existing models. In order to increase consumer value, and hence competitiveness, it is necessary to develop excavation equipment in several areas, an important role belongs to improving the materials of the mechanical component of the excavator, as well as improving the interaction of man and machine based on the principles of ergonomics and engineering psychology. The work presents an original software product created to solve the automation problem of the ergonomic reengineering process with the possibility of ranking models of mining excavators by the comfort level in the cab.