Effect of a Boiling Additive on R123 Condensation on a Vertical Integral-Fin Surface.
Effect of a Boiling Additive on R123 Condensation on a
Vertical Integral-Fin Surface.
Kedzierski, M. A.
NISTIR 6314; 31 p. March 1999.
International Journal of Refrigeration, Vol. 23,
Available from: National Technical Information Service
(NTIS), Technology Administration, U.S. Department of
Commerce, Springfield, VA 22161.
1-800-553-6847 or 703-605-6000;
Order number: PB99-140543
additives; condensation; heat transfer; refrigerants;
isopentane; binary mixtures; integraltrapezoidal-fin;
This paper examines the effect of the addition of 0.5 %
mass isopentane to R123 on the vapor-space condensation
heat transfer of R123. In a previous study, the pool
boiling performance of R123 was improved by adding 0.5 %
mass isopentane. Consequently, the impetus of the
present study was a desire to quantify the consequence
of the boiling additive on the condensation heat
transfer performance of pure R123. In this way, the net
effect of the additive on the cycle performance of pure
R123 can be estimated. The data consisted of the heat
flux and the wall temperature difference measurements
for pure R123 and R123/isopentane (99.5/0.5) on an
integral-trapezoidal-fin surface. The temperature of the
saturated vapor was held constant at 3 13.15 K for all
of the tests. On average, the R123/isopentane mixture
exhibited a 4 % smaller heat flux than that of pure
R123. Presumably, the degradation was caused by the
zeotropic behavior of the mixture, which led to a loss
of available driving temperature difference for heat
transfer across the liquid film. Considering that the
boiling performance was enhanced on average by 10 % with
the addition of 0.5 % mass isopentane, isopentane may
still be a viable means of improving the cycle
performance of R123 despite the 4 % condensation heat