POULTRY HENS at Glenhead of Aldouran, Stranraer, not only produce thousands of eggs, but also generate heat and power for the farm via a biomass boiler that burns their manure.

This innovative approach to powering the farm – and managing the regular power cuts that affect the area – was developed by Glenhead of Aldouran's owner, James Baxter, using an Organic Rankine Cycle system, powered by Novec Engineered Fluids from 3M.

Manure from the 128,000 free-range hens fires a bed biomass boiler which feeds an E-RATIONAL ORC UHT 111/90kWe system, which in turn generates heat and power. The boiler produces hot water at 150°C, providing 750Wth of heat to be recovered by the ORC.

Within that, the Novec engineered fluid is used to absorb heat from the chicken manure, converting into a vapour, which drives a turbine before condensing and being rerouted to the heat source.

The average electrical power of 65kWe is used on-site for local consumption. 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, with a distribution system transferring the heat to the different henneries.

Importantly for the area, 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.

Mr Baxter explained: “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.”

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.