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

Abstract

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 to 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 (PMV) and Predicted Percentage of Dissatisfied (PPD) 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.