This content is not included in your SAE MOBILUS subscription, or you are not logged in.
A Simple Model for Calculating Vehicle Thermal Loads
ISSN: 0148-7191, e-ISSN: 2688-3627
Published April 08, 2013 by SAE International in United States
Annotation ability available
One of the most fundamental parameters for designing an automotive HVAC system is the thermal load, also known as cooling load. The major contributors to the thermal load inside the cabin of an automobile are solar loads, occupant loads, infiltration loads and loads due to various electrical fittings and the engine. Simple but accurate predictions of the thermal load inside the cabin will help engineers in designing and developing an efficient mobile air conditioning system.
While commercial software are available for simulating these loads, such tools require tedious and time-consuming modeling of components involving many parameters as well as multiple iterations. A simple method for computation of the vehicle thermal load that requires a minimum of input parameters will be useful in situations where a full-scale analysis is not required.
A computer model has been prepared for this purpose at Mahindra & Mahindra. The model calculates total thermal load by considering four major sources of heat: solar radiation, air leakage, electrical fittings and the occupants.
For the solar load, the location and time specific solar irradiance (both direct and diffuse) and the angle of incidence with different panels are considered. The heat transfer coefficients are calculated for all panels considering boundary layer conditions.
The model's accuracy is verified with test results from wind tunnel tests.
CitationJha, K., Bhanot, V., and Ryali, V., "A Simple Model for Calculating Vehicle Thermal Loads," SAE Technical Paper 2013-01-0855, 2013, https://doi.org/10.4271/2013-01-0855.
- ASHRAE 2009 ASHRAE Fundamentals Handbook Atlanta, GA
- Churchill S.W. A comprehensive correlating equation for forced convection from flat plates AIChE J. 22 264 268 1976
- Lienhard , J.H. and Lienhard , J.H. A Heat Transfer Text-book Philington Press Cambridge, MA 100486479315 2011
- Malik , T. , Bullard , C.W. Air Conditioning Hybrid Electric Vehicles while Stopped in Traffic University of Illinois ACRC Technical Report TR-230 June 2004
- Zheng , Y. , Mark , B. , and Youmans , H. A Simple Method to Calculate Vehicle Heat Load SAE Technical Paper 2011-01-0127 2011 10.4271/2011-01-0127
- Ingersoll , J. , Kalman , T. , Maxwell , L. , and Niemiec , R. Automobile Passenger Compartment Thermal Comfort Model - Part II: Human Thermal Comfort Calculation SAE Technical Paper 920266 1992 10.4271/920266