High Efficiency Waste Heat Recovery/Refrigeration Unit

This project will deliver a proof of concept, validated with hardware experimentation, of an
innovative system for efficient ICE waste heat recovery with mobile refrigeration/air
conditioning benefits. This system will use low grade waste heat sources like the coolant loop
of an IC engine to drive a Dearman heat-engine that uses liquid nitrogen (LN2) as a ‘fuel’ and
cold source; the heat-engine will be used to peak shave the IC engine's duty cycle and the
liquid nitrogen will be used as a source of cold for air conditioning or refrigeration when
required.
The primary market for this technology is likely to be urban Heavy Duty Vehicles (HDVs),
including refrigerated delivery trucks and city buses. An optimised system has the potential to
deliver significant diesel fuel savings (up to 30%) and an operator payback of < 2 years for
systems requiring the chilling component and < 3 years for pure heat recovery applications.
Urban HDV operators have significant exposure to fuel price volatility and local air quality
regulation and so are a receptive market. By 2025 it is estimated that the global market for
buses and coaches will be 875k units/yr, of which over 50% will have significant airconditioning
needs. In the same timeframe, urban delivery vehicle sales will be greater than
2.5m units/yr, of which over 300k will be chilled or frozen delivery.
The project will build on existing research into the base Dearman Engine and will focus on
increasing the engine's performance as well as exploring its integration into IC engine thermal
systems. Model-based system exploration of component sizes and configurations will be
supported by research into the response of the Dearman Engine to higher operating pressures
and various grades of IC engine rejected heat. Supporting activity will develop an exploitation
plan including review of markets, feedback from potential users and integrators,
understanding manufacturing options and preparing a plan for a future prototype stage.