2011 International Conference on Alternative Energy in Developing Countries and Emerging Economies
- 164 -
Fig. 3. Relation between void fraction and moisture content for
GABA rice at 20-50% dry-basis.
0.335M
67.164
ε
(10)
with value of R
2
= 0.963 RMSE = 0.665
D. Specific heat capacity (c
p
)
The experimental results were mathematical analyzed
using linear and non-linear regression method. The best
simulated curves for GABA rice were determined using
the highest determination of coefficient and the lowest
RMSE value. Fig. 4 showed the experimental values and
calculated values of specific heat capacity versus
moisture content of 20-50% dry-basis. The results
showed that the specific heat capacity of GABA rice was
directly proportional to the moisture content. The specific
heat capacity decreased from 8.73 to 6.82 kJ/kg
q
C with
increasing moisture content. Relationships of the specific
heat capacity with the moisture content could be
expressed as followings in Eq. (11).
Fig. 4. Relation between specific heat capacity and moisture
content for GABA rice at 20-50% dry-basis.
0.072M
10.417
pc
(11)
with value of R
2
= 0.907 RMSE = 0.240
E. Estimation of Thin-layer drying model
From the experiment, the comparison of moisture
ratios and drying time of thin-layer drying for GABA
Sungyod rice were dried by using air impingement dryer
and infrared radiation of 1000 W. The experiments were
carried out at drying temperatures of 60 to 100
q
C and
initial moisture content of 47 to 51 %dry-basis.
The fitting of the moisture ratio was found to be
exponential form and has function of the temperatures
there are shown in Table 4. It was found that empirical
drying of Page’s and Midlili’s model was good fit model
to describe the moisture ratio with drying time of GABA
Sungyod rice that gives the lowest RMSE and the highest
R
2
for drying with air impingement dryer and infrared
radiation of 1000 W, respectively.
TABLE 4
EMPIRICAL CONSTANT AND STATISTICAL RESULTS
OBTAINED FROM DIFFERENT THIN-LAYER DRYING MODELS
FOR DIFFERENT DRYING
Tech.
of
drying
Constant of Model
R
2
RMSE
Page Model
IP
k=
230.8444exp(2897.2182/T)
n=0.90742
0.9969 0.0121
IR
k=
5.6480exp(1906.9295/T)
n=1.09954
0.9913 0.0211
Lewis Model
IP
k=
399.4001exp(3171.2502/T)
0.9775 0.0290
IR
k=
4.2965exp(1703.6457/T)
0.9882 0.2075
Henderson and Pabis Model
IP
k=
403.0462exp(3180.7981/T)
a=0.9907
0.9780 0.0287
IR
k=
4.5068exp(1707.8176/T)
a=1.0237
0.9903 0.0223
Logarithmic Model
IP
k=
562.2858exp(3165.7532/T)
a=0.7916 b=0.2098
0.9811 0.0269
IR
k=
4.4048exp(1722.8205/T)
a=1.0618 b=-0.0413
0.9904 0.0222
Midilli Model
IP
k=
132.9259exp(2709.7604/T)
a=1.0008 b=0.0033
n=0.96854
0.9803 0.0274
IR
k=
1.8360exp(1618.7832/T)
a=0.9982 b=0.0045
n=1.3012
0.9972 0.0119
N
OTICE: IP=H
OT AIR BY
I
MPINGING TECHNIQUE
IR=I
NFRARED RADIATION
40
45
50
55
60
65
0 10 20 30 40 50 60
Void fraction (%)
Moisture content (%d.b)
Experimentaldata
(Sungyod)
Model(Sungyod)
4
5
6
7
8
9
10
0 10 20 30 40 50 60
Specific heat capacity
(kJ/kg.K)
Moisture content (%d.b)
Experimentaldata
(Sungyod)
Model(Sungyod)
