Organic Rankine Cycle
Innovative ORC solution generated by ‘hen power’
The hens at Glenhead of Aldouran’s farm are very busy. Not content with producing thousands of eggs, they also create enough chicken manure to fire a bed biomass boiler which feeds an E-RATIONAL ORC UHT 111/90kWe system, generating heat and power back into the farm. The boiler produces hot water at 150°C, providing 750Wth of heat to be recovered by the ORC. The condenser side of the ORC runs on warm water with an average temperature of 65°C. The warm water returning from the ORC is used to heat the chicken sheds of the sites; a distribution system transferring the heat to the different henneries. In this way, 100% of the heat generated by the boiler is utilised either as power, or as heat itself for the farm.
The average electrical power of 65kWe is used on-site for local consumption. Because the area suffers from regular power cuts, the ORC machine is equipped with an off-grid cabinet and in case of power outage, can run in island mode. A diesel generator is used as an emergency unit to assist the ORC, and an on-site wind turbine is used for power generation.
James Baxter, owner of Glenhead of Aldouran Farm explains: “This biomass project is a win-win-win. The chicken manure is processed and the boiler ash can be reused as fertiliser because of its remaining nutrients. The electricity is used on site to save on utility costs. And the chicken sheds are heated with the condensing heat of the ORC, therefore we don’t need a separate wood chip boiler to heat the sheds. An additional advantage is that our farm is fully independent in case of failure with the grid connection”.
E-RATIONAL are specialists in converting low temperature waste heat into clean energy without emissions. E-RATIONAL developed the state-of-the-art ORC technology for the Glenhead of Aldouran farm, utilising 3M™ Novec™ 7100 Engineered Fluid as the fluid used to absorb heat from the chicken manure. Novec fluid is converted into a vapour, which drives a turbine before condensing and being re-routed to the heat source. There were several drivers for selection of Novec fluid as the optimum fluid for this application:
• Thermal stability: Novec fluids offer long term thermal stability at the maximum cycle temperature, and are non-corrosive, to protect the integrity of coils, seals and other system components
• Safety: Novec fluids are non‑flammable and low in toxicity
• Sustainable: Novec fluids have low global warming potential and zero ozone depletion potential, and, unlike HFCs which are also used in ORC applications, are not targeted for phase-down or phase-out
The E-RATIONAL ORC at the Glenhead of Aldouran farm has been designed to maximise uptime and efficiency with a minimised operational and maintenance cost. The containerised modular machine is CE-compliant, with plug-and-play connections for easy installation at the farm. The ORC machines from E-RATIONAL can convert heat from various sources, such as industrial processes, or utilise unused excess heat from district heating networks. In the case of the farm, it’s the chickens’ own waste that is converted into keeping them warm, a virtuous ‘circular economy’ approach that is sure to give other farms inspiration for their own waste management.