Numerical simulation on the influence of solar incidence angle on the car internal flow field
This paper simulates and analyzes non-uniform thermal environment in the cabin by means of CFD. The RNG k -ε turbulent model is chosen, and the Discrete Ordinates radiation model is used to calculate the thermal radiation of the cabin. This paper analyses the influence of three different solar incidence angles on the thermal comfort of car occupants. A reference for the optimal research of the evaluation of indoor comfortable environment is given.
Effects of Spectral Properties of Glass on Thermal Comfort of Car Occupants
Abstract The effect of different sources of radiation on the transmissive and reflective performance of glass was investigated to enable the accurate evaluation of solar radiation through a glass window. The performance of these two properties is quite different with different radiation sources, such as solar radiation from the sun or infrared solar lamps, because of the spectral properties of both the glass and radiation sources. We also discuss how differences in the transmissive and reflective performance of the glass affect the thermal comfort of car occupants. A numerical simulation method, based on comprehensive combined analysis of a thermoregulation model of the human body, radiation models, including thermal radiation and solar radiation, and computational fluid dynamics (CFD) is conducted for this purpose. In addition, the numerical simulation method was combined with a numerical thermal manikin model, including the algorithm for the control system of the thermal manikin, and tested for its effectiveness for the evaluation of thermal comfort. It was shown that the numerical model performed equally well and therefore could be used as a substitute for the thermal manikin for the assessment of equivalent temperature in the experiments discussed in ISO/NP-14505.
Evaluation of the Effects of Air Conditioning Operation and Associated Environmental Conditions on Vehicle Emissions and Fuel Economy
The Coordinating Research Council (CRC), California Air Resources Board (ARB), and Texas Commission on Environmental Quality sponsored a program to evaluate the effects of air conditioning (AC) operation on vehicle emissions and fuel economy. Phase 1 of this work measured the effect of AC use with vehicles operated over several standard driving cycles and verified results previously obtained by other investigators. Phase 2 provided a better understanding of the effects of the interactions between ambient conditions (solar load, temperature, and humidity) and AC operation on emissions and fuel economy. The Phase 2 program also verified results of Phase 1 by using a different population of vehicles. The program results demonstrated that AC operation had a substantial impact on emissions and fuel consumption. Operation of the vehicle AC system over a range of environmental conditions resulted in consistent increases in vehicle emissions of nitrogen oxides (NO x ) and carbon monoxide (CO). NO x increased from 0.1 to 0.6 g/mile, depending on the severity of the test cycle and ambient conditions. CO increased from 0.5 to 12 g/mile. However, analyses indicated that increases in CO were actually due to the increases in ambient temperatures that were employed in the experiments. The application of solar load to the vehicle increased the impact of AC operation. The application of solar load increased NO x emissions from 0.10 to 0.14 g/mile. Although this experiment was not designed to specifically address fuel economy, operation of the vehicle AC system caused substantial decreases in vehicle fuel economy, ranging from 2.5 to 4.5 miles/gallon. The addition of solar load increased the effect on fuel economy, primarily at less severe ambient conditions. Solar load caused a decrease of 1.3 miles/gallon at 80°F and moderate humidity. The results of the program were intended to aid in the improvement of vehicle emissions inventory models. NO x emission increases due to the use of AC ranged from 15% to 100% of baseline values. This level of effect indicates that AC use should be well accounted for in these models.