Waste Heat Utilization

Elsevier, Thermal Science and Engineering Progress, Volume 7, September 2018
Rural communities in developing countries often require small cold storage for vital medicines while having no access to electricity. The utilization of waste heat – produced in biomass burning cookstoves during daily cooking routines – to power a thermoacoustic engine driving a thermoacoustic refrigerator is investigated. The simplicity and affordability is met by the use of atmospheric air as working medium, cheap PVC ducting for acoustic waveguides and locally available blacksmithing technologies for simple heat exchangers.
The internal combustion engine (ICE) does not efficiently convert chemical energy into mechanical energy. A majority of this energy is dissipated as heat in the exhaust and coolant. Rather than directly improving the efficiency of the engine, efforts are being made to improve the efficiency of the engine indirectly by using a waste heat recovery system. Two promising technologies that were found to be useful for this purpose were thermoelectric generators (TEGs) and heat pipes. Both TEGs and heat pipes are solid state, passive, silent, scalable and durable.