Harnessing Heat

Liquid air boils and turns back into a gas at -196C and therefore any temperature above this will boil the liquid (i.e. turning it back into a gas).

Our engines therefore work at all ambient temperatures (Alaska to Dubai); but the hotter the environmental / added heat the more efficiently the engine will operate and the greater the power output. While the engine can operate using ambient heat, it can also provide a highly efficient and inexpensive use for environmental waste heat, converting it to power.

Our engine is in fact ~70% efficient at converting waste heat back into power, including low-grade heat (e.g. below 100C).

To put this in context, this is five times more efficient than traditional heat recovery engines (such as an organic rankine cycle engine).

There is heat being exhausted to the environment everywhere – be it the braking system of a car, the heat in the passenger cabin, the refrigerator of a chilled delivery vehicle or for static applications, the waste heat of air conditioning, data centre cooling or industrial processes.

In fact as a world, for all the energy we consume at least another 50% is lost as waste heat; in our cars more than 60% of the available energy is lost either through the radiator or exhaust.

Conversion of Low Grade Waste Heat into Power

About two thirds of the fuel energy input to an internal combustion engine (IC engine) is converted into heat energy, i.e. only one third actually becomes shaft power. Currently this heat energy is wasted and rejected to the environment equally through the radiator or exhaust systems. While there is investment in technologies to capture a limited amount of the higher temperature waste heat of the exhaust, the radiator’s low temperature remains a key challenge.

The Dearman Engine offers the opportunity of converting wasted engine heat (critically including easily accessible low grade heat from the radiator) into additional shaft power. It has the potential to do this at very high efficiency as the cycle starting temperature is very low (-196’C). Practical conversion efficiencies of radiator coolant waste heat to shaft power as high as 50% could be achievable.

Our proposal is to use a Dearman Engine alongside an IC engine to provide an additional zero emission power source utilising heat that would otherwise be rejected, this could:

  1. reduce the size of the ICE;
  2. significantly reduce losses associated with heat rejection (including the parasitic loads to drive the cooling systems or drag associated with radiator air flow), and
  3. reduce fuel consumption and tailpipe emissions

These benefits can be additive to other energy saving devices. The IC engine is likely to be the dominant technology in a number of critical transport markets for the foreseeable future. Consequently, a technology that enhances its efficiency and de facto reduces tail-pipe CO2 by this magnitude – and at an acceptable cost - is likely to have widespread applications.