Chris Franklin, Chairman at Ranheat Engineering Ltd – a leading UK manufacturer of wood combustion equipment – continues his series of articles exclusively for Furniture & Joinery Production Magazine. This edition, he writes about uses for heat from your wood-waste boiler or heater during the summer months.
The waste heat generated by boilers and heaters during the summer months can be redirected for various beneficial uses. It’s also important to recognise that wood waste produced during the wood manufacturing process must be managed and disposed of effectively to ensure smooth factory operations.
Recently, there have been changes regarding the use of fine wood dusts — primarily, but not exclusively — in agricultural animal bedding. The use of these fine dusts in such applications is no longer permitted.
Given these developments, the following options are now under consideration:
- Send it to landfill.
- Burn it and reject the heat into atmosphere.
- Produce Briquettes for storing and use in the winter.
- Use the heat for process loads such as drying water-based paint finishes.
- Use in kilning processes, either for kiln drying or heat treatment (pallets).
- Produce electricity.
- Produce cooling for the factory.
The seven options above are the most obvious but not exclusive uses of wood-waste during non-heating periods. Let’s look at the for and against for each method.
Option 1: Landfill disposal
This is the simplest option, but likely the most expensive. In addition to transportation costs, you’ll need to cover gate fees and the landfill tax charged by the receiving site. Fine dusts such as MDF “flour” may also need to be bagged before disposal, adding to the overall expense.
Option 2: Burn it and reject the heat into atmosphere
It sounds bad for the environment, but decomposing wood-waste in landfill gives off 25 times more greenhouse gases than combustion.
Option 3: Produce briquettes for storing and use in the winter
Turning fine dust into briquettes is an option, but it comes with challenges. The process consumes a significant amount of electricity, and without a binding agent, the briquettes tend to break down over time, often reverting back to dust. Briquettes made from 100% fine dust are generally low in quality and not ideal for storage or use. This option also raises a strategic question: Is the primary goal to manufacture product, or to become a fuel supplier?
Use heat for process loads
Redirecting waste heat to support processes like drying water-based paint finishes is highly effective, particularly if your facility already operates a paint line or has substantial painting operations.
Use in kilning processes, either for kiln drying or heat treatment
While kilns are costly and kiln drying is a specialised process, this option may be a clear advantage, especially if you’re manufacturing pallets.
Produce electricity
This could be an expensive option, but if you have enough wood-waste it could be viable. Mainly using the ORC method (Organic Rankine Cycle) or possibly a Sterling engine for small-scale production.
Produce cooling for the factory
Not as silly as it sounds, but might be used abroad in hotter countries as cooling in the summer can cost more than heating in the winter.
So, these are the various ways that your wood-waste could be used in the summer. It’s probably too late for this year, but worth a look for 2026, particularly given that the summers do seem to be getting hotter.
As well as the boiler/heater system design considerations, there are also the permitting requirements for burning wood-waste at any time of the year. All wood-waste burning operations require a permit to burn waste that is a by-product of a wood machining process, even if burning Virgin Timber.
The systems are divided into three ranges, up to 50kg/hr. up to 90 kg/hr and over 90kgs/hr. There are theww different permits or exemptions, one for each size.
All installations must have planning permission for the chimney (or written permitted development); installations need chimney height approval from environmental health, and all of these permits and permissions must be in place before the installation goes ahead.
Finally, all installations must meet the guidance as laid down in the MCPD (Medium Combustion Plants Directive. Unlike previous legislation, the MCPD is retrospective, and will apply to all installations by 2030. Plants over 5MW had to comply by 1st January 2025 and plants under 5MW have until 2030.
Contact Ranheat for further information on all types and sizes of industrial woodburning equipment from 75 kW upwards.
01604 750005
