3 research outputs found
Design and construction of an oven for drying palm bunch using glycerine as fuel together with using closed-loop oscillating heat-pipe with check valves (CLOHP/CV) heat exchanger for waste heat recovery
138-143This research addresses
design and construction of an oven (2 m x 3 m x 2 m) for effectively drying
palm bunch using glycerin as a fuel and a closed-loop oscillating heat-pipe
with check valves (CLOHP/CV) as a heat exchanger for waste heat recovery. In
each experiment, palm bunches (500 kg) were baked in oven with and without
CLOHP/CV heat exchanger. CLOHP/CV (0.2 m x 0.8 m x 0.5 m) is made of copper
tubes (inner diam, 2.03 mm). Working fluids were distilled water, ethanol and
R134a. Waste heat from oven was recovered by heat exchanger and was beneficial
for pre-heating the air in combustion process. Pre-heating was useful in
burning glycerine, and distribution of heat inside oven with CLOHP/CV was
better than without CLOHP/CV. Consequently, palm bunches received uniform heat
that restrained enzyme thus slowing dissolution reactions that would otherwise
produce free fatty acids and cause loss of palm oil. Use of a CLOHP/CV also
reduced moisture content of palm bunches to 1.2 wt% on dry basis. When using
oven with CLOHP/CV as a heat exchanger with R134a as working fluid, the highest
thermal efficiency of drying palm bunch was 42.4%, highest effectiveness of
CLOHP/CV was 43.0% and highest efficiency of glycerin stove was 45.0%
Measurement of internal pressure and thermal performance in a closed-loop oscillating heat-pipe with check valves (CLOHP/CV)
531-540<span style="mso-bidi-font-family:
AdvEPSTIM;mso-fareast-language:JA" lang="EN-GB">The internal
pressure and the thermal performance as characteristic parameters in a
closed-loop oscillating heat-pipe with check valves (CLOHP/CV) under the normal
operating condition have been investigated experimentally. The test CLOHP/CV
was made of a copper capillary tube with various inner diameters. The
inclination angle and the working temperature have been varied in the
experiments. The working fluids of distilled water, ethanol and R123 were used
with a filling ratio 50% of the total internal tube volume; the
number of meandering turns was 40 and the number of check valves was 2. The
lengths of the evaporator, adiabatic and condenser sections are all the same.
The evaporator section was heated by electric strip heaters. The heat was
removed from the condenser section by forced convective flow of ambient air
blowing through the sections. The adiabatic section was well insulated by foam
insulation. The thermal performance of the CLOHP/CV was evaluated by
calculating the rate of heat transferred from the condenser to ambient air. It
was found that the thermal performance of the CLOHP/CV has been improved by
increasing the working temperature, the inclination angle and the inner
diameter. The best performance of all the test CLOHP/CVs occurred for the case
of R123 as working fluid, 2.03
mm inner diameter, 90° inclination angle and the working temperature of 200°C, where the maximum internal pressure was 7.53 MPa and the minimum
thermal resistance was 0.048°C/W.
</span