Mini CHP delivers the benefits of large scale CHP,
but within smaller developments.
This can also minimise distribution losses,
resulting in a very high overall utilisation of
fuel, saving money and carbon.
Can make use of biofuels to provide even better
efficient heat & power production
electrical efficiency than larger CHP
specific cost than larger CHP
Cost effective energy
and carbon savings for extremely large homes, farms,
schools and small hotels.
|Micro CHP is defined by
the UK Government as being CHP with an electrical output less than
50kWe; this clearly includes units far too big for individual homes
for which products up to 3kWe and normally around the 1kWe level are
most common. The micro CHP section
deals with the very smallest products (<5kWe) suitable for
individual family homes; this section deals only with
products from 5-50kWe (also known as "mini CHP") more
suitable for small hotels, sheltered housing, schools and small
Although there are developments in a number of mini CHP technologies,
the most commonly encountered are based on ICE (Internal Combustion
Engines); early products simply took automotive engines and adapted
them for stationary use, with consequent very poor performance.
Modern mini CHP products, however, use engines specifically designed
for long life and extended service intervals; although regular
service is required, this is less of an issue with units installed
in plant rooms and where professional maintenance contracts,
including remote monitoring are in place.
As with micro CHP, the economics of mini CHP depend primarily on the
generation of electricity; electricity is significantly more
valuable than heat both in economic and carbon terms. Thus, in
order to maximise the value of this generation, it is desirable to
run the system for as many hours per year as possible, so that
products with high electrical efficiency (and relatively low heat
output) are desirable. However, it is also important that the
cost of the product does not result in extended payback periods;
typically up to 10 years is considered viable for public sector
applications, although well designed systems can achieve much