Bulb drying and district heating

Location: Aberdeenshire

Customer: Bulb growing and pig farm

The requirement was to provide heat and power for farm energy requirements, drying crops and providing power and heat to farm building, offices and the main house. To meet the requirements a wood chip gasifier and combined heat & power unit was installed along with two biomass boilers.

Purpose of Project / Business Challenge:

The project required a renewable energy heating and power solution to provide heat for the farm’s operational requirements and also to the home. The main business is growing bulbs which are harvested and then required to be dried in barns using warm air. In addition to this there are also pigs kept indoors requiring additional heat.

Biosus Energy Limited designed a district heating system with heat and power generated by one wood chip Combined Heating and Power unit – CHP (95kw heat & 45kw power) and two Biomass Boilers (130kw & 200kw heat).  The electrical power generated by the CHP is used by the farm, with any excess power being sold to the grid.

The boilers and CHP were all connected to 2 x 6000 litre buffer tanks.  They heat the water in these buffer tanks.  Hot water from the top of these buffer tanks is fed into the hot water manifold and distributed on 3 circuits.  The manifold has the option to expand with 2 additional circuits if required.

The district heating included;

  • Bulb shed with 14 heaters above 14 fans in main bulb drying area with thermostatic control
  • Piggery
  • Grading shed
  • Workshop
  • Farmhouse
  • Offices
  • Drying floor radiator

In addition to this, heat from the plant room was extracted and directed into the wood chip feed bin, keeping  the CHP wood chip below 10% moisture content.

Benefits / Business Case:

Reduced carbon footprint with replacement of fossil fuels

Switching from the grid power and oil heating has provided an economical and sustainable energy solution.

All power and heat requirements met by CHP and biomass boilers.

30kW power exported to the grid generating revenue stream.

RHI income for biomass boilers and CHP

Additional control enabled the ability to maintain critical temperature to avoid any crop damage during drying.

District heating installed to meet all farm and accommodation heating requirements