Application of an Evolution Program for Refirgerant Circuitry Optimization.
Application of an Evolution Program for Refirgerant
Circuitry Optimization.
(6630 K)
Domanski, P. A.; Yashar, D. A.
Challenges to Sustainability. ACRECONF 2007.
Proceedings. December 7-8, 2007, New Delhi, India, 1-16
pp, 2007.
Keywords:
refirgerants; air conditioning; heat exchanger;
algorithms; temperature; thermophysical properties;
evaporators; entrophy; cooling; air distribution;
computational fluid dynamics
Abstract:
Increased concerns about climate change have emphasized
the importance of air-conditioning and refrigeration
systems with a high coefficient of performance (COP).
The effectiveness of heat exchangers significantly
influences the vapor-compression system's COP.
Evolutionary algorithms provide an opportunity to
optimize engineering designs of heat exchangers beyond
what is typically feasible for humans. This paper
presents a summary of our past and most recent work with
finned-tube heat exchangers using an evolutionary
program, Intelligent System for Heat Exchanger Design
(ISHED), which optimizes refrigerant circuitry. The
experiments with ISHED included evaporators and
condensers working with refrigerants of vastly different
thermophysical properties and heat exchangers exposed to
non-uniform air distributions. In all cases, ISHED
generated circuitry designs that were as good as or
better than those prepared manually. Further simulations
showed that the COP ranking of R600a, R290, R134a, R22,
R410A, and R32 in systems with optimized heat exchangers
differed trom the ranking obtained using theoretical
cycle analysis. In the system simulations, the
high-pressure refrigerants overcame the thermodynamic
disadvantage associated with their low critical
temperature and had higher COPs than the low-pressure
refrigerants.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899