The choice of system and storage volume depends on several factors such as the thermal load to cover the fuel type selected, the available space, the size of the truck to recharge, the reliability of supply, boiler space, warehouse, etc. . It is recommended that small houses install flexible silos of between 2 and 5 tons. Starting with these measures we can make concrete silos.

Flexible Silos

Storage for this type of system is calculated for one or two annual recharge seasons considering 1500 hours. Canvas or polypropylene, this system is ideal in locations where there is sufficient space for installation. The silo is supported by a metal structure permeable to air but not dust. The capacity of these silos is between 2 and 5 tons of fuel. This type of store has the advantage of being able to use available habitats and adapt easily to the store. It can be installed both inside and outside the building.

If the silo is located on the outside, it must be protected from rain and ultraviolet rays. It is also necessary to ensure that the floor can support the weight of the full silo and withstand wind. A concrete base 50 cm high x 50 cm long x 50 cm deep at the base of each FlexiTank pole would be sufficient for that purpose.

Silo Sizing

As the estimated ratio for 1 kW of installed capacity needed is about 200-250 kg of pellets or olive pits per year, equivalent to about 900 kWh

Room measurements

The action plan of the room where you place the flexible silo must be at least 7-10 cm longer than the flexible silo. For installation requirements an additional distance of 30 cm of separation between the flexible silo wall and where the supply tube (coupled with the flexible silo) enters is needed. The height of the room for the assembly of a flexible silo must be at least 220 cm. The fire resistance of walls and ceiling of the room for the assembly of flexible silo and the room where the boiler will be installed need to conform with current standards of construction and local anti-fire regulations.

Works Silos

Its most important feature is the absence of moisture, since it makes the biomass increase in volume and lose some of its properties as a fuel

Requirements of the storage room

Lack of moisture

Electrical installations within the store are not allowed.

It should provide a procedure to empty the storage of biofuel if necessary, necessary for carrying out maintenance work.

In new buildings the minimum storage capacity of biofuels must be sufficient to cover the consumption of two weeks.

In existing thermal plants that are reformed, where there cannot be a division in two separate locations, the storage tank will be located at a distance of 0.7 m above the boiler and must exist between the heat generator and a storage wall resistance to fire in accordance with existing fire protection regulations.

Maintenance of the screw (once a year to clean the dust and the bearings lubricated screw).

According to the SI Basic Security Document (page 13) in case of fire the Technical Building Code (CTE), storage of solid fuel for heating are classified under the medium risk level and must meet their demands for security.

Source: Biomass and Waste Dept. of http://www.idae.es/ with a group of specialists in biomass for thermal applications coordinated by Scan, SA