130kW Orligno 600 Hot Air Log Boiler
Brampton Woodworks
As a supplier of firewood as well as manufacturing timber structures and signposts, there was a requirement for a facility to kiln dry logs and space heat a large workshop. After initially looking to install a log boiler, accumulator and unit heater system, the capital cost and reduced non-domestic RHI tariff made this option unattractive. This conclusion was then compounded by the decision of Ofgem to exclude log drying processes from the RHI scheme altogether.
Finding a Solution
The owner Robert approached SandS Heating Solutions to see if they could come up with a cheaper alternative to the water based drying systems currently on offer. SandS had long thought that it was extremely wasteful and inefficient to turn heat from the combustion process into hot water and then back into hot air through a unit heater. This method had only become common place as RHI payments could only be made for measured heat output and this could only be achieved by using a hot water heat meter. There was no easy way to measure hot air. SandS had been trialling a new type of boiler supplied by Eco Angus called an Orligno 600 which was capable of turning heat from the combustion process directly into hot air. It was rated at 40kW which was nowhere near enough output for what was required. SandS used the technology from the 40kW Orligno 600 to adapt the 130kW Angus Super to provide a bespoke solution to the problem.
130kW Orligno 600
The boiler was housed in a custom made external shelter and was fitted with two 200mm spigots which could deliver a stream of clean hot air to the adjacent kiln or to the attached workshop via ducting. Each duct was fitted with a butterfly valve which allowed the air flow to be adjusted or turned on or off as desired.
Performance
The boiler delivers a constant stream of clean air at 120 degrees C to the kiln at a rate of 22m3 per minute (dedicated) or 13.8m3 per minute when the workshop is being heated. The boiler is throttled back to 50 degrees C output overnight and its slumber mode ensures that there is still wood ready to go the following morning so the boiler doesn't have to be constantly re-lit. The kiln is made up of a 38 foot container which has been insulated internally.
Kiln Design and Performance
The kiln can be loaded with 13 net bags of wet hardwood logs, typically weighing around 420Kg each. The boiler is then run for up to seven days.
During the drying process, temperature and humidity values are monitored using external displays of the internal environment throughout the kiln. Once it has been determined that the logs have dried sufficiently they are removed. A dried bag of logs can be up to 90Kg lighter (90L of water removed).