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Future By Energy

CHP (Micro-CHP)

Small combined heat and power (CHP) systems are now becoming available for individual houses, block of houses and small non-domestic premises. CHP at the large commercial size is now common in premises which have a simultaneous demand for
heating and electricity for long periods, such as hospitals, recreational centres, hotels and nurseries. Compared with using electricity, CHP can offer a more efficient and economic method of supplying energy demand.

CHP for small buildings is now available as a result of the development of small gas- (or oil-) fired engines, linked to electric generators, with heat available for use in the building.
Most systems replace (or run in parallel with) a domestic sized boiler and will be connected directly into the building electricity distribution system. Heat generated will be used for space and water heating, and additional heat storage may be used to increase use periods (help to warm-up and to improve overall energy efficiency).
For overall good energy efficiency, as with all CHP, usage must be heat demand led.

There are currently two types of mechanical engines available:
• Internal combustion engines
• Stirling engines

Internal combustion engine systems normally supply an electrical output more than 5kW, with a heat output of upwards of 10kW. They are normally suitable for groups of flats, grouped residential buildings such as nursing homes, and some small commercial premises, depending on the heat demand.
The units will normally be located in a dedicated boiler house and will need to run for more than 10 hours a day to be economic.
Stirling engine systems use a ‘heat engine’ as the motive force for the generator, and these units are available with an electricity output of around 1 kW upwards. With a power to heat ratio of between 6:1 and 3:1, these systems are most suitable for larger new houses, older houses with high heat demand and some small commercial premises. Stirling engine systems cannot be modulated rapidly and take couple of minutes to start up and close shut down. Thus, they cannot be used in quite the same way as traditional domestic boilers, which are normally sized for maximum start-up loads and cycle on/off to maintain required temperatures. Peak heat demand can be supplied by an integral or separate heat-only source or by using a water-based heat storage system so they need steady-state heat demand.
Other CHP systems under development include fuel cells. Fuel cells chemically convert hydrogen into electricity and heat. Hydrogen can be made from fossil fuels, normally natural gas, or may be available in the future from other renewable sources. Fuel cells are still at the development and testing stage, and it is not known how they will operate in the domestic and small commercial situation.
Micro-CHP systems offer the potential to reduce carbon emissions, but their operation and interaction with the buildings in which they operate is very complex. Understanding of the energy performance and carbon savings benefits is developing these devices are unlikely to be appropriate for new flats and houses with small heat loss.

Calculations of overall system efficiencies are complicated as they must consider the heat output together with the effects of the displaced electricity from central generation via the grid. The calculation methodology is given below. Micro-CHP calculations are in the revised SAP methodology.
A new Publicly Available Specification (PAS) for laboratory testing micro-CHP packages intended for use in dwellings is being prepared. The PAS describes a procedure to measure heating and electrical performance under a range of standardised operating conditions. When this is available, the results of testing will be fed into the calculation methods.
For the purpose of calculating the potential of a micro-CHP system to contribute towards lowering the carbon dioxide emissions of a building in order for it to meet the compliance requirements of Part L of the Building Regulations, the factors to be considered are:
CHP (Micro-CHP)
Ground cooling


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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.