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The traditional thermal environment management of the passenger compartment adopts the unified regulation method. Air distribution formed in this manner often causes thermal comfort and energy consumption problems. In view of the problems of conventional airflow organization, a new air supply strategy-variable air volume and temperature strategy is proposed. In this air supply strategy, variable air volume and variable temperature air supply is carried out according to the characteristics of thermal comfort requirements of passengers in different periods and positions in the cabin. STAR-CCM + software coupled with THESUES-FE software was implemented and compared with different air supply methods. The performance of the air supply strategy was evaluated based on PMV-PPD evaluation index. The results show that the variable air volume variable temperature air supply strategy has certain advantages and improves the thermal comfort level of the crew cabin. The cooling capacity of the automobile air conditioning is allocated effectively, thus improving the satisfaction of the occupants to the thermal environment. This strategy not only saves energy, but also improves the cooling effect in the cabin. [ABSTRACT FROM AUTHOR]

Trains are an important means of transportation for people to travel. The train's soft sleeper compartment space is relatively small, and the density of people is relatively large. Therefore, improving the thermal comfort and air quality of the compartment is of great significance for ensuring a healthy travel environment. To analyze the appropriate mode of conditioned air supply in train soft sleeper compartments, the airflow distribution inside soft sleeper compartments is simulated numerically at four different air supply modes, namely, sidewall air supply with slot diffusers, perforated ceiling air supply, bedside task–ambient air conditioning, and displacement ventilation. The reliability of the numerical simulation models is verified with the experimental data in the literature. Comparative analysis is made in terms of the compartment temperature, velocity, predicted mean vote and predicted percentage dissatisfied (PMV-PPD), and ventilation efficiency among various modes of air supply. The four air supply schemes are evaluated comprehensively by stochastic multicriteria acceptability analysis (SMAA-2). As the computational results show, bedside task–ambient air conditioning is the best air supply mode in terms of comprehensive performance indicators, followed by the sidewall slot air supply. The perforated ceiling air supply ranks third, and is superior to displacement ventilation. [ABSTRACT FROM AUTHOR]

Highlights • The bottom-supply mode and side-supply mode were studied contrastively. • The simulation results were validated by the physical experiment in the laboratory. • The indoor thermal environment, PPD and energy utilization efficiency were explored. • The bottom-supply mode provided better thermal comfort and lower energy saving. Abstract The growing energy consumption and thermal comfort of an air-conditioned room have attracted increasing public attention. As such, the performance of air-conditioning systems with two air supply modes for a simplified office room was studied by numerical simulation and physical experiment. An experimental investigation was developed in an environmental chamber to validate the simulation model. Numerical investigation was carried out subsequently for an office setting by the validated CFD model. The indoor thermal environment, human thermal comfort and energy utilization efficiency of two air supply modes were analyzed and compared in this study. The results showed that under both air supply modes, thermal stratification occurred in the model room, and the air flow velocity in the occupied zone was low. In addition, the results indicated that under 21 °C supply temperature, the air-conditioning system with bottom-supply mode provided better indoor thermal comfort of the occupied zone, but the energy consumption was higher than the side-supply mode. [ABSTRACT FROM AUTHOR]

• The system is applied to buildings with high moisture load. • Two-stage air dehumidification is adopted to distribute moisture load. • Seven operating modes are designed to match various environmental conditions. • Energy efficiency increases 3.19%-10.57% by regenerated air heating. • The better system performance could be obtained at low ambient air enthalpy. With the higher demand for indoor thermal comfort and the accurate control of air temperature and humidity, energy consumption in air conditioning systems is increasing over these years, especially for buildings with high moisture load such as natatoriums. However, freezing dehumidification is still widely adopted in eliminating moisture load, which requires lower evaporating temperature and causes excessive energy consumption. To improve energy utilization and efficiency, a heat pump-driven liquid desiccant dehumidification system is proposed in this research, the surface condenser and liquid desiccant dehumidifier are adopted to realize two-stage air dehumidification. In the summer condition, the solution in regenerator is heated by the condenser of heat pump and the residual heat is to heat the regenerated air, and the cooling capacity of heat pump is applied to the surface condenser and terminal heat exchanger, simultaneously the solution in dehumidifier is cooled by cooling tower. Under the meteorological conditions in Nanjing, the coefficient of performance could reach 6.148 in this proposed system, and compared to conventional air source heat pump dehumidification air conditioning system, the rising ratio of energy efficiency is between 11.4% and 80.7%. Eight cities in China are selected to analyze the energy-saving effects, and energy consumption could be reduced by 31.9%-63.2%, the result demonstrates the superior energy-saving potential and application prospect of the heat pump-driven liquid desiccant dehumidification system. [ABSTRACT FROM AUTHOR]

This study investigated the annual energy saving potential and system performance of two different evaporative cooling-based liquid desiccant and evaporative cooling-assisted air conditioning systems. One system used an indirect and direct evaporative cooler with a two-stage package to match the target supply air point. The other was equipped with a single-stage, packaged dew-point evaporative cooler that used a portion of the process air, which had been dehumidified in advance. Systems installed with the two evaporative coolers were compared to determine which one was more energy efficient and which one could provide better thermal comfort for building occupants in a given climate zone, using detailed simulation data. The detailed energy consumption data of these two systems were estimated using an engineering equation solver with each component model. The results showed that the liquid desiccant and dew-point evaporative-cooler-assisted 100% outdoor air system (LDEOAS) resulted in approximately 34% more annual primary energy consumption than that of the liquid desiccant and the indirect and direct evaporative-cooler-assisted 100% outdoor air system (LDIDECOAS). However, the LDEOAS could provide drier and cooler supply air, compared with the LDIDECOAS. In conclusion, LDIDECOAS has a higher energy saving potential than LDEOAS, with an acceptable level of thermal comfort. [ABSTRACT FROM AUTHOR]