2011 International Conference on Alternative Energy in Developing Countries and Emerging Economies
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Fig. 7. The water temperature in various position of storage tank when
having load condition.
Fig.
8
.
The heat rates from solar collector.
Fig. 9. The electric powers of the auxiliary heater on 3 consecutive
cloudy days.
For the standard mass flow rate, the average daily
useful heat from the solar collector was 17.30 MJ and the
average daily system efficiency was 53.09%. For the
controlled mass flow rate condition, the average daily
useful heat was 24.89 MJ and the average daily system
efficiency was 76.36%.
The average daily auxiliary heat
were 22.77 and 16.81 MJ, respectively.
VI. C
ONCLUSION
For a solar hot water heating system with a water
temperature- stratified storage tank, control of mass flow
rate to be less than the standard value could get more
daily heat from solar collector especially on a cloudy day.
The results of a nursery building on 3 consecutive cloudy
days showed that controlling of the solar collector mass
flow rate could get more daily solar heat and spend less
daily auxiliary heat compared with that of the standard
flow rate. For the standard mass flow rate condition, the
average daily useful heat from the solar collector was
17.30 MJ and the average daily auxiliary heat was 22.77
MJ while for the controlled mass flow rate, the average
daily useful heat was 24.89 MJ and the average daily
auxiliary heat was 16.81 MJ.
A
CKNOWLEDGEMENT
The author would like to thank the Commission on
Higher Education, Thailand for supporting by grant fund
under the program Strategic Scholarships for Frontier
Research Network for the Ph.D. Program Thai Doctoral
degree for this research. The authors would like to thank
the Graduate School and Thermal System Research Unit,
Department of Mechanical Engineering, Faculty of
Engineering, Chiang Mai University for supporting
testing facilities.
R
EFERENCES
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0
200
400
600
800
1,000
1,200
1,400
0
10
20
30
40
50
60
Solar radiation (W/m
2
)
Temperature(
o
C)
Ts3,standard
Ts3,control
Solar radiation
(
c) The water
temperature at node3 of storage tank
0
500
1,000
1,500
2,000
2,500
Qu(W)
Qu,standard flow rate
Qu ,control flow rate
0
1000
2000
3000
4000
5000
6000
7000
Auxiliary (W)
Auxiliary,standard flow ratet
Auxiliary,control flow rate
