Our customer wanted to lower the heating costs for their site. The decision to install a biomass boiler was made, but a requirement of the project was to be able to burn a wide range of fuels in order to maximise the long term payback on the investment and to ensure future fuel costs remained as low as possible.
costs per kW of heat produced as low as 1.2p/kWh
The Justsen Argusflex Ceramic boiler was chosen for the project because of its robust industrial design. The Justsen Flex boiler is uniquely designed to burn wet or dry fuels. The design of the boiler features a fully water filled combustion chamber module, which means that the side walls and grate of the boiler are cooled by the return water from the heating system. This limits the combustion temperatures, which allow the use of very dry fuels and fuels with high ash content that are prone to the formation of clinker. The ceramic version installed has factory installed ceramic tiles installed on the water cooled walls, insulating key areas of the combustion process from the cooling effects, and therefore increasing the maximum fuel moisture the boiler can burn up to 55% moisture. This flexibility allows the use of the wood fuel that is available at the best price in the local area. The extra capital cost is offset by the ability to burn low cost fuels, with the customer reporting costs per kW of heat produced as low as 1.2p/kWh. Longevity of the installation was a key consideration, with the RHI subsidy set to run for a period of 20years.
the boiler of choice in town district heating plants in Denmark
The boiler was installed in winter 2014 and was sized to handle base load heating duty, with peak load and backup covered by an oil fired boiler. Space has been left in the plant room for an additional biomass boiler which may be installed if and when expansion of the glasshouse occurs. The fuel store has been designed to feed a second boiler in tandem with the first. The existing heating system incorporates a large thermal store, which helps to minimise oil consumption by allowing the biomass to run and charge the buffer tank even when there is little or no heating load in the glasshouses. This continuous loading is important for burning wet fuels, as the fire should not be allowed to go out as relighting with wet fuels is difficult. Running in this way increase the capacity factor of the boiler. Capacity factor is a measure which quantifies how hard the boiler works in terms of its theoretical maximum heat output over a year. For example, if a boiler was to run at 100% output continuously through the year, the capacity factor would be 100%. Boilers in domestic / commercial environments typically run at 15% or less, while base load boilers in a glasshouse may easily exceed 50% capacity factor. This is a key consideration when selecting a biomass boiler, with many boilers not designed for sustained use at high outputs. The Justsen Flex range is ideally suited due to its heritage as the boiler of choice in town district heating plants in Denmark and around the world.
Telephone: +44 (0)1263 577 301
Hall Farm House, Aldborough
Norwich, Norfolk, NR11 7HU