New technology can help eliminate the cost of fuel – and earn revenue from government under RHI

Installations of heat-pump systems for drying grain and heating buildings are gathering pace as growers in Scotland recognise the financial attractions of ground-sourced renewable energy.

According to Calibrate Energy Engineering, a specialist supplier based near Alnwick, Northumberland, a heatpump installation can earn revenues from the government renewable heat initiative (RHI) for 20 years while eliminating the cost of fuel otherwise needed to heat air for drying.

It also produces chilled air that can be used to cool the grain in store to prevent pest infestation and in winter can heat one or more farm houses and/or a workshop.

Newly-installed systems include two 1,000kw packages in Aberdeenshire and the Scottish Borders said to be earning RHI at 9.36p/kwh while running at 500% efficiency drying grain.

The heat-pump grain dryer technology, recognised by the Royal Highland and Agricultural Society of Scotland this year with a silver medal for innovation, harvests naturally-occurring heat by circulating fluid through a series of pipes buried in the ground.

This heat is concentrated by the heatpump process – a bit like refrigeration but creating heat rather than cold – which is used when necessary to warm air drawn into the store at ambient temperature to increase its moisturecarrying capacity and so remove moisture from the grain.

Instead of being exhausted to the atmosphere as with a conventional drying system, this moisture-laden air is passed through the heat-pump dehumidifier, so creating a continuous loop that Calibrate says requires less energy than usual.

The “cool only” function at the end of the cycle brings the grain temperature down to a suitable level for storage.

In terms of practicality, the company points out that the heat-pump drying system can be installed in an existing store as well as incorporated into a new build, and the controller technology installed enables functions to be monitored remotely on a mobile device or farm office computer.

The company offers leasing plans with a choice of 20-year lease or lease-thenpurchase options, as well as purchasing finance if required.