文档介绍：APPLIED
Applied Energy 84 (2007) 553–564 ENERGY
ate/apenergy
Application of closed-loop oscillating heat-pipe
with check valves (CLOHP/CV) air-preheater
for reduced relative-humidity in drying systems
P. Meena *, S. Rittidech, N. Poomsa-ad
Faculty of Engineering, Mahasarakham University, Thailand
Available online 17 November 2006
Abstract
This paper aims to design, construct, and test the CLOHP/CV air-preheater for reduced relative
humidity in drying systems for recovering the waste heat from the drying cycle. The CLOHP/CV
heat-exchanger consisted of m long copper tubes, with an internal diameter of m. The
evaporator and condenser sections were m long, the adiabatic sections were m long, the
hot-air velocities were , and 1 m/s with the hot-air temperatures being 50, 60 and 70 °C,
and the relative humidity was 100%. The working fluid was R134a with the filling ratio of 50%. It
can be concluded that, with an increase in the hot-air temperature from 50 to 70 °C, the heat-transfer
rate slightly increases. The velocity increases from , to 1 m/s and the heat-transfer rate
slightly decreases. The velocity increases from , to 1 m/s and the effectiveness slightly
decreases. The hot-air temperature increases from 50 to 70 °C and the effectiveness slightly increases.
The relative humidity reduced to the range 54–72% from 89% to 100%. The CLOHP/CV air-pre-
heater can reduce the relative humidity and achieve energy thrift.
Ó 2006 Elsevier Ltd. All rights reserved.
Keywords: Closed-loop oscillating heat-pipe; Check valves; Air-preheater; Relative humidity; Heat recovery;
Drying system
* Corresponding author. Tel./fax: +66 43 754316.
E-mail address: @ (P. Meena).
0306-2619/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved.
doi:.
554 P. Meena et al. / Applied Energy 84 (2007) 553–564
Nomenclature
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Bo Bond number Di