Modern Building Services
Hoval extends the capability of wood-pellet boilers
Published:  09 April, 2005

Fully automatic central heating using a Hoval boiler fuelled by wood pellets has replaced an oil boiler for a project in Switzerland. This is the first Hoval wood-pellet plant of this scale; previous installations had outputs up to 26 kW.

For ecological and political reasons, the building owners no longer wanted to use an oil-fired boiler, but cost-benefit analysis was against the use of a heat pump.

In response to an approach from Griesser Installation AG, Hoval developed a boiler for field testing.

The existing oil tank for the project became the storage room for 7 t of wood pellets. Using an Archimedian screw and turbine, pellets are delivered to the boiler.

The boiler has automatic ignition and control of combustion air using a variable-speed fan that enables output to be modulated from 50 kW down to 15 kW. Noise levels are comparable with the previous oil-fired boiler.

There are plans to develop heating products using pellets with outputs from 70 to 100 kW this autumn.