An automobile preheating system which can improve automobile performance, reduce emission levels and enhance passenger comfort during a cold start was developed. This system utilizes heat from the exhaust of the automobile which would otherwise be wasted into the environment. Thermal energy from the exhaust is stored during engine operation in the form of chemical energy through the dehydration of lithium bromide. This energy can be stored indefinitely with no insulation and be recovered through the re-hydration of the lithium bromide. Upon hydration, heat is evolved which can be used for various preheating functions prior to a vehicle cold start. When required, the thermal battery could be used to) increase passenger comfort and safety by heating the cabin and defrosting the windshield, ii) improve engine performance and lower pollutant emission levels by heating the engine and catalytic converter, and iii) increase the cranking power of the battery by raising its temperature. A prototype of the thermal battery was designed, constructed and tested. Experiments verified the feasibility of such a system.