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Future By Energy

Biomass

Biomass is an alternative solid fuel to the conventional fossil fuels and has an impact on carbon emissions that is close to neutral or zero. Different types of biomass fuel are in use, the most common being the woody biomass, which includes forest residues such as tree thinning, and energy crops such as willow short rotation coppice.

For building applications, the fuel usually takes the form of wood chips, logs and pellets. Wood pellets are essentially compacted high-density/low moist wood. Supply and storage of the biomass fuel should be carefully considered especially for larger plants.

The typical applications are:

• Biomass boilers replacing standard gas- or oil-fired boilers for space heating and hot water
• Stand alone room heaters for space heating.
• Stoves with back boilers, supplying domestic hot water.
• Biomass CHP for heat and electricity generation.

Appliances can achieve efficiencies of more that 80%. Sizes start at 3-5kW capacity for room heaters and 100+ kW or MW for industrial-scale plants and community energy schemes.

Applications of small-scale boilers and individual room heaters are increasing.
An integrated hot water storage tank or an accumulator can enable the supply of heat to be decoupled from the actual combustion of the fuel.
The capital cost of automated biomass heating systems is greater than that of conventional ones, mainly because of the more complicated feeding mechanisms.
A typical 10 kW automated domestic biomass stove would cost between £1,600 and £2,100, and the fuel prices are around £50-60 per tonne of woodchip (25% moisture content) and £170-200 per tonne of delivered wood pellets.

Biomass CHP plants are suitable for larger scale projects and appear viable at capacities above 0.5MW.

The main benefit of biomass technology is the significantly reduced level of carbon emissions owing to the fuel carrying zero (or very close to zero) carbon burden. Many biomass fuels transported for greater distances than 25 miles can also be regarded as carbon neutral because the alternative destination of the fuel is often land-fill where it would decompose to generate methane, which is significantly more potent as a greenhouse gas than CO2.

Building space and organization to accommodate and operate the plant
Biomass boilers for individual dwellings (15-50kW) are floor standing and no larger than a standard kitchen unit (600 x 600 x 900). Larger boilers for non-domestic or community energy applications will require plant room space similar to their gas or oil counterparts. Outside access to the plant room and storage is important for handling the delivered fuel, which should be appropriate to its means of transportation.
Biomass boilers have to run for some time before they achieve the desired output temperature and hence some form of heat storage is necessary to provide instant heating and hot water. Storage also allows the boiler to operate at a higher efficiency as lower temperatures over a longer burning time is a better and more sustainable method. Additional space may be required for a hot water storage tank, which for a standard house could be up to 1,000 litres.

As a replacement for domestic gas or oil boilers, biomass boilers will need to meet the total heating and hot water demand of the dwelling, so it should match the capacity of existing boiler.
For non-domestic buildings, relying solely on biomass entails some risk because of the possible unreliability of the fuel supply and need for short periods of down time for maintenance. As biomass boilers are significantly more expensive than gas or oil boilers, it is both safer and cheaper to size the biomass boiler to meet a base load, and to provide additional top-up/backup gas or oil boilers.For preliminary calculations, 50% of the annual heat demand can be used as a guide.
They require a flue or chimney outlet and a constant supply of fresh air through a permanent opening. Most woody fuels are suitable for burning, and manufacturers’ recommendations should be given in the system specification.
Fuel storage will depend on the heater capacity and the proportion of the heating demand.

Additional design issues that need to be addressed for biomass plants include:

Ventilation: Biomass appliances in principle require significant combustion air and can create a visible smoke discharge in some conditions.

Noise: Again for ventilation reasons, larger fans are installed on biomass boilers, which may result in increased noise levels. The fuel supply mechanism will also cause noise

Safety: Handling and feeding fuel into the burner should be undertaken with care.The risk of incomplete combustion is solved by a number of in-built mechanisms in most boilers,

Currently, there is a wide range of biomass systems on the market with specific characteristics and requirements. Installation should be carried out by a suitably qualified HETAS installer.
In this situation, the boiler controls should shut off the fuel supply and shut down the boiler. Locating the boiler on the ground to provide a thermosyphon and provision of a safety pressure valve are also recommended. New models now allow the system to be fully pumped and sealed from the atmosphere.
New biomass boilers can have a high level of mechanical sophistication, with automatic fuel feed, self-adjustment of sensors and performance self-test. They are simpler to operate and only the main performance parameters can be directly controlled without the need for a qualified professional.
Setting the boiler temperature is vital.Biomass boilers run more efficiently and last longer with high combustion and return temperatures. Similarly, the speed of the circulation pump and thermostatic bypass must be set correctly and this requires awareness of the demand levels.


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02081440820
Future By Energy
Future By Energy

Future BY Energy

Future BY Energy Ltd is a professional energy assessor company with a rich understanding of the UK energy market. We offer independent professional expertise in mechanical engineering for all domestic and commercial buildings and strategic energy advice. As expert designers and specifiers of heating-cooling systems, we pride ourselves in finding affordable energy efficient solutions for new and existing buildings. We have top level experience in a wide range of building types in both commercial and domestic sectors.
As registered energy assessors we provide:

• Domestic Energy Performance Certificates (EPC)
• SAP calculation and predicted energy assessment for new built dwellings (EPC-SAP/PartL)
• SBEM calculation for Commercial buildings (SBEM/Part L)
• Commercial Energy Performance Certificates (EPC)
• Display Energy Certificates for Public buildings (DEC)
• Air Conditioning Inspections (TM44)
• Asbestos surveys and consultancy
• Air permeability-Leakage test
• Sound test and acoustic consultancy

Please do not hesitate to contact, Behdad Yazdani, on 02081440820, who will be pleased to advise you.