C O N T E N T S

from the computational model, fact that validated the numerical
model and the comprised hypothesis. The validation was obtained
not only for nominal functioning regime but also for partial loads
and for the whole range of inlet water temperatures used for the
boiler.
Key words: condensation boilers, goffered tubes, heat transfer.
MESURES DE LA PRESSION INSTANTANÉE DANS UN
COMPRESSEUR À PISTON ET COMPARAISON AVEC DES
RÉSULTATS THÉORIQUES
par
DAN ANDREI
Abstract. The resolution of the six first order and second order
differential equations (two first order equations and four second-order)
that make up the mathematical model of a pulsating pressure compressor
operation [1], [2], [3] is made by the Runge-Kutta fourth order method.
Variation diagrams of pressure in the compressor cylinder, of the total
pressure in the pressure chamber and of the displacement of the
discharge valve were obtained for three operating regimes with
compression ratios: H1 = =3.4, H1 = 4.5 and H1 = 5.6.
Key words: acoustics, pulsating pressure, reciprocating compressor.
ENERGY RECOVERY OF COMBUSTIBLE GASES FROM
GEOTHERMAL WATERS BY COGENERATION UNITS WITH
INTERNAL COMBUSTION ENGINES
by
ANA-MARIA BIANCHI, SORIN DIMITRIU and FLORIN
BĂLTĂREŢU
Abstract. In some geothermal fields, the hot water is associated
with high content hydrocarbons gases, especially methane. These gases,
which can reach to a content of 2…2.5 m 3 N per cubic meter of water and
can have a methane content of 85…90%, represent an important power
potential. This paper presents the possibility of power potential recovery
of these gases using gas engine cogeneration units. A case study is
performed, regarding the geothermal water wells working in