Table 1.

Summary of proposals for waste energy recovery in other projects.

	Common Elements	Differentiating Elements	Advantages	Drawbacks
GASTone	Energy recovery and storage.	Recovery of kinetic energy through a belt driven generator and waste heat with an energy cascading approach.	Vehicle efficiency well above 50% at an acceptable cost.	Requires engine modification for the adoption of this solution.
TRIPOD	Optimization of energy consumption thanks to energy recovery.	Integration of podded propulsion and tip loaded endplate propellers in combination with energy recovery based on counter-rotating propeller (CRP) principle.	High potential in fuel savings and emission reductions	The main propeller is driven by a 2-stroke engine which produces high emission.
HEATRECAR	Efficient use of the energy wasted in the form of heat in thermal engines.	The power module converts heat energy directly into electricity.	Reduction of fuel consumption and abatement of CO2 emissions due to the reduced mechanical load at the crankshaf.	Conversion of a exhaust gases into electricity, but there is no reduction of electricity consumption.
INTHEAT	Heat recovery using heat transfer units.	Method for dealing with the main exchanger geometry details in HEN retrofit problems.	Energy consumption in crude oil distillation could be decreased by 30% using the heat recovery system.	FT values increase the computation difficulty for optimizing HEN retrofit problems.