Th
ermodynamic analysis of an unconv
entional h
eat
engin
e was p
erform
ed. Th
e engin
e studi
ed has a numb
er of advantag
es compar
ed to stat
e-of-th
e-art
Stirling engin
es. Th
e main advantag
e of th
e engin
e propos
ed is its simplicity. A pow
er piston is int
egral with a displac
er and a h
eat r
eg
en
erator. It allows solving th
e probl
em of th
e high-t
emp
eratur
e s
ealing of th
e piston and th
e displac
er typical of all typ
es of Stirling
engin
es. In addition th
e d
esign propos
ed provid
es id
eal us
e of th
e displac
er volum
e eliminating h
eat loss
es from outsid
e gas circuit. Both strok
es of th
e piston ar
e working on
es in contrary to any oth
er typ
es of piston
engin
es. Th
e engin
e can b
e consid
er
ed as maint
enanc
e-fr
ee as it has no piston rings or any oth
er rubbing compon
ents r
equiring lubrication. Th
e only s
eal is contactl
ess and w
ear fr
ee. It is locat
ed in th
e cold part of th
e cylind
er. As a r
esult th
e l
eakag
e rat
e in op
eration can b
e on
e-two ord
ers of magnitud
e as small as that in Stirling
engin
es. Balancing of th
e engin
e is much
easy compar
ed to Stirling
engin
es with two r
eciprocating mass
es b
ecaus
e of th
e only moving part insid
e th
e engin
e cylind
er. Th
e engin
e suits id
eally to b
e fu
ell
ed with 鈥渄ifficult鈥?fu
els such as bio oil and can b
e us
ed as a prim
e mov
er for micro-CHP syst
ems.
The thermodynamic model developed incorporates non-ideal features of the cycle, such as specific regenerator efficiency, dead volumes and other geometrical parameters of the engine. The model shows that the energy efficiency is highly sensitive to regenerator performance. For realistic geometric and operating parameters and the regenerator efficiency of about 95%the ultimate energy conversion efficiency of the engine proposed can be as high as 40-50%.
A prototype of the engine was built and the feasibility of the engine concept was demonstrated.