A worked example from the authors’ paper. The stated outputs depend on batch volume, drying schedule and fuel quality. Equipment and operating parameters must be confirmed for each project.
Complex configuration
The paper considers three chambers: two SK-136 units at 50 m³ each and one SK-272 at 100 m³. The total of 200 m³ refers to the assumed batch volume. Actual capacity depends on board thickness, pack dimensions and spacers.
Insulation and energy use
The authors compare rigid polyurethane foam and mineral wool by thermal conductivity and resistance to water-vapour diffusion. Insulation thickness and moisture, enclosure sealing and thermal bridges all affect the selection. For 40 mm pine boards and fuel moisture of 40%, the example assumes 3.0 kW/m³ for a polyurethane-insulated chamber and 4.5 kW/m³ for a mineral-wool-insulated chamber.
Boiler output calculation
With all three chambers operating simultaneously, the authors calculate 600 kW for polyurethane insulation and 900 kW for mineral wool. For fuel moisture of approximately 60%, the paper adds 30% to the required rated output. Staggered chamber operation reduces peak demand by 20% in this example.
| Scenario in the paper | Rigid polyurethane | Mineral wool |
|---|---|---|
| Fuel up to 40% moisture, simultaneous operation | 600 kW | 900 kW |
| Fuel around 60% moisture, simultaneous operation | 780 kW | 1170 kW |
| Fuel up to 40% moisture, staggered operation | 480 kW | — |
| Fuel around 60% moisture, staggered operation | 624 kW | — |
The proposed 600 kW plant does not automatically cover every scenario in the table. Wet-fuel scenarios requiring 624–780 kW need a separate review of rated output and chamber scheduling.
Chamber specifications
| Parameter | SK-136 | SK-272 |
|---|---|---|
| Number of chambers in the complex | 2 | 1 |
| Capacity with 40 mm boards | 50 m³ | 100 m³ |
| Capacity with 25 mm boards | 41 m³ | 80 m³ |
| Capacity with 50 mm boards | 53 m³ | 115 m³ |
| External dimensions, W × D × H | 6,73 × 7,24 × 5,6 m | 13,23 × 7,24 × 5,6 m |
| Installed electrical power | 13,1 kW | 26,2 kW |
| Maximum boiler thermal output per chamber | 185 kW | 370 kW |
| Number of fans | 4 | 8 |
| Wall / roof thickness | 100 / 140 mm | 100 / 140 mm |
| Controls | AS-200 | AS-200 |
The chamber specification lists 185 and 370 kW. These use different design conditions from the 150 and 300 kW drying example. Heating and drying schedules must be confirmed when selecting equipment.
Boiler plant and fuel handling
The specification lists a KWH-600 boiler, an AZSD-500/RR combustion unit with moving grates and automatic ash removal, EcoControl controls, an HWP-40/2 hydraulic fuel extractor, a ZPU screw conveyor and a B-600 multicyclone with a WWOax-25 induced-draught fan. The example provides storage for 100 m³ of loose fuel.
The authors select HAMECH SK chambers with a KWH + AZSD heat source. For a particular site, confirm timber species and thickness, initial and final moisture, chamber loading schedules and fuel properties.
Full original paper
This web version presents the main calculations and equipment package. The original DOC includes the full text, graphs, technical explanations and specification.
Download the full paper