| Author | Mastekbayeva, Gauhar A. |
| Call Number | AIT Thesis no. ET-98-1 |
| Subject(s) | Solar dryers--Asian Institute of Technology
|
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of
Engineering, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Abstract | This study presents the work done to studies on improve the performance of the solar
tunnel dryer fabricated at AIT. Specifically, its performance at no load and load conditions,
using fans powered by photovoltaics as well as from grid electricity; influence of dust on the
transmittance of the plastic cover and the performance of the collector; and the design and
preliminary tests on a solar- biomass dryer were done. The load experiments were with chilli,
which was dried at all these three operating conditions.
No load tests conducted on AIT solar tunnel dryer have shown that temperatures above
40°C were obtained by AC- driven solar tmmel dryer. The drying temperatures of the air are
maintained at relatively steady level in case of using PV- drive due to control of air flow rate
by the incident solar radiation. The air temperature, flow rate and relative humidity in the
collector- dryer have been measured during the day and analysed. The test results during AC
and PV operation of this dryer have been compared with existing solar tmmel dryers in
literature which show the performance of this tmmel dryer superior.
The experiments on drying of chilli was conducted on AIT solar tunnel dryer for both
AC and PV driven fans. The drying time compared to open sun drying, was reduced by the
40% and by the 60% respectively. Since, only a part of the total dryer capacity was utilised, the
system efficiency was low at about 4.3% (AC- operation) and about 6.6% (PY-operation). The
performance of the chilli drying have been compared to note the influence of the various
parameters, such as drying time, air flow rate (for PV), air temperature and relative humidity.
These have been compared with other data in the literature for which limited data was
available. The quality of the final dried chilli was found to be good.
The design of the biomass stove and heat exchanger has been done and existing solar
dryer has been modified for use allowing the dryer to be used during the rainy season.
Preliminary tests on this new hybrid system have shown that the effectiveness of the heat
exchanger is about 74%. The collector has been used as a mixing box to achieve the required
uniform temperature at the dryer inlet. The efficiency of the stove-heat exchanger unit has
been found to be about 24%. Using a solar- biomass hybrid dryer, the drying of 19 kg of chilli
was done in one day. A full load test (70 kg of chilli) was been done on the solar- biomass
hybrid system within two days.
An experimental study on the dust influence on the plastic transmittance has been
quantitatively studied for five different dust densities. The dust correction factor has been
found for the transmittance of the UV-stabilised 0.2 mm thickness polyethylene film inclined
at 15 degrees from the horizontal for 30 days of exposure at Bangkok and the quantity of dust
settled from the air on plastic sheet has been found of the order 3.7 g/m2
. |
| Year | 1998 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Energy and Climate Change (Former title: Department of Energy, Environment, and Climate Change (DEECC)) |
| Academic Program/FoS | Energy Technology (ET) |
| Chairperson(s) | Kumar, S. |
| Examination Committee(s) | Attalage, R. A. ;Athapol Noomhorm |
| Scholarship Donor(s) | Government of Japan |
| Degree | Thesis (M. Eng.) - Asian Institute of Technology, 1998 |