L E Barnes & Sons Ltd - Roxhill Manor Farm

Background

For a number of years all heating and hot water was provided by a straw bale fired boiler. The unit was fuelled by Ø1.8m linseed bales and additionally wood pallets were also occasionally used. Hot water from the boiler was used to provide heat to 50 domestic radiators and a swimming pool.

A number of problems existed with the installation, principally poor combustion and excessive tarring. The tarring problem was exacerbated if wheat straw was burnt. Additionally there was very little draught produced by the chimney stack, resulting in smoke issuing from the boiler. In addition the boiler required daily attention with regard to filling it with bales and cleaning it out.

In 2005 Asgard Biomass Systems were approached by L E Barnes & Sons Ltd to recommend a replacement biomass boiler system, which should have the capability to burn a variety of different materials.

Solution

As a working farm there are a number of crops available for use as a fuel, including oilseed, wheat, barley and oats. Additionally, operating as contractors, L E Barnes & Sons Ltd has a regular supply of spoiled grain which has no commercial value.

With a large heating load in the winter but only hot water required during the summer months a twin boiler installation was recommended. A 75Kw KSM Hybren and a KSM 20kW Automatic F boiler unit are installed. During the summer the smaller unit is used to provide hot water, while in the winter the 75kW boiler provides both space heating and hot water. During extremely cold periods both boilers operate together.

Installed Boiler Type

KSM Multistoker 775-75 Hybren

This unit is equipped with its own cold press unit that allows the use of oilseed as a fuel source. Oilseed is crushed in the press and oil is extracted, which is then pumped into storage vessels. The remaining oilseed cake, which has a 10% oil content is burnt in the boiler. Oilseed oil can be used for a variety of uses, including cooking oil and as a feedstock for biodiesel. In addition this unit also burns wheat, which together with the oilseed is stored in a split bin hopper above the unit.

KSM Multistoker 275-18 Automatic

This unit is fed from a bin mounted directly above it and is used primarily with grain crops such as wheat, barley and oats. However it could also run equally well with wood pellets. Due to the tendency for wheat to form clinker a small quantity of quick lime to added (2% by volume) to the fuel to reduce this tendency. Also the boiler is equipped with a moving floor heath to ensure any clinker build up is avoided.