| Internal
Combustion Engines offer significant advantages over external combustion
in many applications, particularly automotive where there is a need for
rapid variation in power output, which can be achieved by changing the
fuel supply rate. However, for continuous operation with extended
service intervals, as required for domestic heating systems, the
challenges facing ICE are formidable; until recently it was considered
that the cost of the components required to achieve the appropriate emissions,
efficiency and reliability parameters would be excessive.
Early products, based on automotive ICE technology, operated with some success in niche applications, but have been unable to overcome these technical challenges being been beset with high service and operating costs. The products mentioned below, however, have all been developed for long life with relatively low service intervention and incorporate a range of features aimed at achieving the performance desirable for domestic and small commercial applications. For further discussion of the relative merits of these engine types see section on papers. |
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| Ecopower | Baxi Dachs | Ecowill | EC Power |
| Based
on Marathon gas engine designed for dry operation and can be modulated
to match electrical load. This feature is believed by its
developers to offer significant benefits over its competitors.
However, the high capital cost of all these products implies very high running hours at full load in order to generate sufficient electricity to recover the investment. It is only in remote (off-grid) applications where this feature offers significant benefits. Ecopower has been acquired by Vaillant, the German boiler manufacturer who are also developing the Plug Power based fuel cell micro CHP unit. |
Developed
and manufactured by the Baxi Group company Senertec GmbH, the DACHS is a
European manufactured packaged mini-CHP unit based on reciprocating
engine technology. Operating reliably and successfully across Europe for
many years, the DACHS is proven technology and has become an established
choice in mini-CHP. Over 8,000 units have now been installed by Senertec
GmbH, and its partner network.
Its primary application is for small hotels and apartment blocks (e.g. sheltered housing) where there is a continuous electrical and thermal baseload. The resulting high annual operating hours provide the substantial savings required to pay back the relatively high capital cost. However, it is physically too large and has too
high an electrical output to be suitable for anything but the largest
family homes, or those with swimming pools. |
Honda’s
small household cogeneration unit combines the GE160V—the world’s
smallest natural gas engine—with a lightweight generation system
employing Honda’s unique sine-wave inverter technology to create a
compact unit suitable for home use.
Although the unit is
the world’s first practical cogeneration unit for home use, in its
current configuration it is not suitable for indoor installation.
However, the incorporation of catalytic converters and an elaborate
acoustic attenuation system, together with novel engine design, have
overcome the principle limitations of ICE design. The cost of
these additional components results in a very high installed cost, which
is difficult to justify on economic grounds. In the Japanese
market, where thousands of these units have been installed, high
electricity prices and capital grants greatly improve the economic
viability for the end user. |
Not
really a micro CHP unit, but included here for those with an interest in
small apartment blocks, sheltered housing etc.
Based on the Lister diesel engines renowned for long life. |
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| For further details contact: | For further details contact: | For further details contact: | For further details contact: |
| Electrical
output
4.5kWe |
Electrical
output
5.3kWe |
Electrical
output
1kWe |
Electrical
output
15kWe |
| Thermal
output
12kWt |
Thermal
output
10.4kWt |
Thermal
output
3kWt |
Thermal
output
35kWt |
| Application
Small commercial |
Application
Small commercial |
Application
Individual family homes (external installation) |
Application
Small commercial |
| Supply only cost | Supply only cost | Supply only cost | Supply only cost |
| Installed
cost
|
Installed
cost
£13000 plus VAT |
Installed
cost
£5600 |
Installed cost |
| Availability
|
Availability
2000 |
Availability
2003 |
Availability
2001 |