Novel Variable Conductance Heat Pipe Coupled with a Stirling Engine

The proposed work involves the design, construction and testing on a micro-combined-heat-and-power (mCHP) unit of a
variable capacity heat pipe (VCHP) in which the mCHP waste heat is managed using one or more (depending upon
capacity of the store) novel heat pipes arranged to link with a phase change material (PCM) thermal store. Novelty lies in
the use of an inert gas inventory in the heat pipe whose pressure can be varied in response to domestic heating demand
and the inclusion of a compact PCM thermal store. Variations in inert gas pressure are used to regulate the domestic
heating system heat exchange surface area (and, hence, capacity) smoothly and continuously, whilst the PCM thermal
store is used to manage the availability of this heat over extended time horizons. Though the proposal is focused on
domestic-scale mCHP applications, the concept is equally applicable to larger scale commercial combined heat and power
plants.
Northumbria's University's contribution is to develop a simulation model of the mCHP unit and VCHP and use the model to
design a domestic-scale experimental pilot rig. The pilot rig will be constructed in Northumbria's Low Carbon Systems
laboratory using an existing Stirling cycle mCHP module. The VCHP unit will be constructed by the collaborators to the
sizing specification designed with the assistance of the simulation model. Northumbria will perform a series of experiments
at thermal demands relevant to typical domestic heating loads - both winter (space heating and hot water) and summer (hot
water only). The intention is to develop the research to a proof-of-concept stage only. A further application of the
simulation model will be used to design system options for a range of house types with differing occupancies and heating
demands. Results will be reported as a basis for possible prototying and field demonstration.

Lead collaborator TWI will play a major role in dissemination. They will ensure that findings related to the project are
effectively disseminated across the relevant industrial sectors. TWI coordinates the Energy Generation and Supply KTN
which will provide a unique means of industrial dissemination for the project.
Presentations will be made at the periodic HEXAG and PIN meetings (in which Professor Reay is coordinator).
Sufficient new research is expected to be delivered for two internatuional journals papers.
A summary outcomes bulletin will be made available for the key practice/industry stakeholders including relevant
equipment manufacturers, architects and professional engineers, builders and installers, building surveyors and community
special interest groups.