E H Mack & Son Ltd. - Grange Farm

Background

Grange Farm at Surlingham near Norwich in Norfolk is an arable farm run by E H Mack & Son Ltd. The farm produces a range of crops, including rapeseed and wheat and has located on site an indoor swimming pool that is open to the public.

Asgard Biomass was asked to visit site to assess the possibility of using a biomass boiler to replace the existing oil and straw fired boilers that were providing heat to the pool and farmhouse.

In addition Asgard was also asked to consider whether it was viable to heat a number of buildings occupied by tenants on site via a district heating system. These buildings consisted of a bungalow, a double dweller and triple dweller houses, all of which were heated by electric storage heaters.

The reason why biomass heating was being considered by the farm’s owners was that in recent years the cost of heating oil had increased and the straw fired boiler was starting to show signs of age. Also the farm was considering the idea of being able to sell heat to its tenants. It was considered that biomass fuels could offer a cheaper source of heating than conventional fossil fuels.

Solution

As a working farm there are a number of crops available for use as a fuel, including rapeseed, wheat, barley and oats. Additionally, located in a rural area, close to managed woodlands, there was the possibility of buying in woodchip.

With a constant heating demand all year round from the swimming pool and from domestic hot water, together with a large space heating demand in the winter months the use of a biomass boiler was very viable. A 95kW KSM Hybren boiler unit was installed, in a barn directly underneath a pair of grain silos. A district heating pipe work system was installed underground to convey heat to the various buildings. On the buildings occupied by tenants, heat meters measure the amount of heat used and this data is used for billing purposes. When rapeseed is used the farm additionally benefits from the production of rapeoil.

Installed Boiler Type

KSM Multistoker 975-95 Hybren

This unit is equipped with its own cold press unit that allows the use of rapeseed as a fuel source. Rapeseed is crushed in the press and oil is extracted, which is then pumped into storage vessels. The remaining rape cake, which has a 10% oil content is burnt in the boiler. Rape 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 rapeseed is stored in the silos above.

An alternative configuration would be to utilise an external hopper attached to the boiler, as with this installation near Belvoir.