Glasshouses & Nurseries - Case Study

Glasshouses growing salads and herbs
System Summary
Boiler type: 
2 x Herz 995 kW BioFire
Fuel type: 
Wood Chip
Fuel store: 
Large fuel store with twin rotary agitator
Our client is based in Essex. They are a large scale salad supply business for British supermarkets (mainly Aldi) and grows cucumbers, peppers and aubergines. The family business is also expanding the site to grow tomatoes in a newly built glasshouse. The site uses high levels of heat to grow salads all year round, with glasshouses and a heating system on a grand scale (some of which was 30 or so years old).
With a number of high profile supermarket supply contracts, the family-run business wanted to cut their fuel costs and integrate biomass with an existing gas CHP system. Towards the end of 2013, the business engaged Rural Energy to find a biomass solution to provide heat to a 400,000l and an 800,000l buffer system with gas CHP. 
Rural Energy specified two 995kW Herz BioFires in separate plant rooms on different parts of the site – one of which integrated with the CHP system. These included large fuel stores with twin rotary agitators and a vertical elevator system for wood chip deliveries.
The fuel stores are ‘block built’ retrofit stores fitted into an existing building. Fuel is elevated from the outside where it is delivered from a trough system vertically and dropped into the fuel store. Fuel is then spread evenly by two filling screws over the top of the wood chip pile. The boiler is fitted beside the fuel store.
This project proved to be complex and Rural Energy dedicated a project team to ensure it could be integrated into the intricate pipework and be suitable to qualify for the Renewable Heat Incentive. Rural Energy’s RHI Coordinator worked closely with external RHI experts to ensure all metering was correctly retrofit.   
The gas CHP system also benefits from a smart environmental control system to manage heat, CO2 and humidity in the glasshouses. This meant that biomass is not used in the ‘typical’ way; rather the heat it provides is managed by this system and injected into the buffer tanks for the glasshouses. Therefore the BioFire had to be incorporated into this intelligent management system too.