Open AccessA MATHEMATICAL MODEL FOR DIRECT EVAPORATIVE COOLING AIR CONDITIONING SYSTEM
Author(s) -
J. R. Camargo,
C. D. Ebinuma,
S. Cardoso
Publication year - 2003
Publication title -
engenharia térmica
Language(s) - English
Resource type - Journals
ISSN - 1676-1790
DOI - 10.5380/reterm.v2i2.3473
Subject(s) - evaporative cooler , air conditioning , vapor compression refrigeration , refrigeration , evaporation , work (physics) , heat transfer , water cooling , coefficient of performance , mechanical engineering , thermal , thermodynamics , mass transfer , process engineering , environmental science , nuclear engineering , engineering , heat exchanger , refrigerant , physics
Air conditioning systems are responsible for increasing men's work
efficiency as well for his comfort, mainly in the warm periods of the year.
Currently, the most used system is the mechanical vapor compression
system. However, in many cases, evaporative cooling system can be an
economical alternative to replace the conventional system, under several
conditions, or as a pre-cooler in the conventional systems. It leads to a
reduction in the operational cost, comparing with systems using only
mechanical refrigeration. Evaporative cooling operates using induced
processes of heat and mass transfer, where water and air are the working
fluids. It consists in water evaporation, induced by the passage of an air
flow, thus decreasing the air temperature. This paper presents the basic
principles of the evaporative cooling process for human thermal comfort,
the principles of operation for the direct evaporative cooling system and
the mathematical development of the equations of thermal exchanges,
allowing the determination of the effectiveness of saturation. It also
presents some results of experimental tests in a direct evaporative cooler
that take place in the Air Conditioning Laboratory at the University of
Taubaté Mechanical Engineering Department, and the experimental results
are used to determinate the convective heat transfer coefficient and to
compare with the mathematical model.