Abstract
We have been developing a high performance solar thermal collector system to obtain hot water near 100°c. We studied the effect of system structures and operation-control methods on the thermal performance of collectors and cost to produce the required amount of heated water through numerical simulations. Four types of thermal collector system structures were examined: (1) a natural convection collector system that collected heat by natural convection of water between the collector plate and the heat storage tank, (2) a heat pipe collector system that collected heat using a heat pipe between the collector plate and the heat storage tank, (3) a water-circulating collector system that circulated water between the collector plate and the heat storage tank with a pump, and (4) an accumulating heated water collector system that supplied new water and accumulated heated water in the heat storage tank. Three operation-control methods were evaluated for the accumulating heated water collector system: (1) the flow rate of the water was controlled to keep a constant outlet-temperature of the heated water, (2) the flow rate of the cooling water was controlled proportionally to match the solar radiation rate, and (3) the flow rate of the water was constant without control. The effects of change in actual daily solar radiation during four seasons were assessed. The results from calculations revealed that the effect of system structures and control methods on the thermal efficiency of the collectors and cost to produce the required amount of heated water was small. The accumulating heated water collector system effectively used solar energy during the day, and the other types effectively used solar energy in the evening. The best method of control to minimize outlet-temperature fluctuations in the heated water and to make the tank-temperature approach the usage temperature was control method (2) (i.e., control with solar radiation).
| Original language | English |
|---|---|
| Title of host publication | OPT-i 2014 - 1st International Conference on Engineering and Applied Sciences Optimization, Proceedings |
| Publisher | National Technical University of Athens |
| Pages | 129-139 |
| Number of pages | 11 |
| ISBN (Electronic) | 9789609999465 |
| Publication status | Published - 2014 Jan 1 |
| Externally published | Yes |
| Event | 1st International Conference on Engineering and Applied Sciences Optimization, OPT-i 2014 - Kos Island, Greece Duration: 2014 Jun 4 → 2014 Jun 6 |
Other
| Other | 1st International Conference on Engineering and Applied Sciences Optimization, OPT-i 2014 |
|---|---|
| Country | Greece |
| City | Kos Island |
| Period | 14/6/4 → 14/6/6 |
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Keywords
- Cost
- Optimal operation control
- Optimal system design
- Solar thermal collector
- Temperature
- Thermal efficiency
ASJC Scopus subject areas
- Computer Science Applications
- Software
- Engineering(all)
Cite this
Optimal system design and operation-control method for evacuated solar thermal collector system to obtain hot water near 100°C. / Hirasawa, Shigeki; Kawanami, Tsuyoshi; Shirai, Katsuaki.
OPT-i 2014 - 1st International Conference on Engineering and Applied Sciences Optimization, Proceedings. National Technical University of Athens, 2014. p. 129-139.Research output: Chapter in Book/Report/Conference proceeding › Conference contribution
}
TY - GEN
T1 - Optimal system design and operation-control method for evacuated solar thermal collector system to obtain hot water near 100°C
AU - Hirasawa, Shigeki
AU - Kawanami, Tsuyoshi
AU - Shirai, Katsuaki
PY - 2014/1/1
Y1 - 2014/1/1
N2 - We have been developing a high performance solar thermal collector system to obtain hot water near 100°c. We studied the effect of system structures and operation-control methods on the thermal performance of collectors and cost to produce the required amount of heated water through numerical simulations. Four types of thermal collector system structures were examined: (1) a natural convection collector system that collected heat by natural convection of water between the collector plate and the heat storage tank, (2) a heat pipe collector system that collected heat using a heat pipe between the collector plate and the heat storage tank, (3) a water-circulating collector system that circulated water between the collector plate and the heat storage tank with a pump, and (4) an accumulating heated water collector system that supplied new water and accumulated heated water in the heat storage tank. Three operation-control methods were evaluated for the accumulating heated water collector system: (1) the flow rate of the water was controlled to keep a constant outlet-temperature of the heated water, (2) the flow rate of the cooling water was controlled proportionally to match the solar radiation rate, and (3) the flow rate of the water was constant without control. The effects of change in actual daily solar radiation during four seasons were assessed. The results from calculations revealed that the effect of system structures and control methods on the thermal efficiency of the collectors and cost to produce the required amount of heated water was small. The accumulating heated water collector system effectively used solar energy during the day, and the other types effectively used solar energy in the evening. The best method of control to minimize outlet-temperature fluctuations in the heated water and to make the tank-temperature approach the usage temperature was control method (2) (i.e., control with solar radiation).
AB - We have been developing a high performance solar thermal collector system to obtain hot water near 100°c. We studied the effect of system structures and operation-control methods on the thermal performance of collectors and cost to produce the required amount of heated water through numerical simulations. Four types of thermal collector system structures were examined: (1) a natural convection collector system that collected heat by natural convection of water between the collector plate and the heat storage tank, (2) a heat pipe collector system that collected heat using a heat pipe between the collector plate and the heat storage tank, (3) a water-circulating collector system that circulated water between the collector plate and the heat storage tank with a pump, and (4) an accumulating heated water collector system that supplied new water and accumulated heated water in the heat storage tank. Three operation-control methods were evaluated for the accumulating heated water collector system: (1) the flow rate of the water was controlled to keep a constant outlet-temperature of the heated water, (2) the flow rate of the cooling water was controlled proportionally to match the solar radiation rate, and (3) the flow rate of the water was constant without control. The effects of change in actual daily solar radiation during four seasons were assessed. The results from calculations revealed that the effect of system structures and control methods on the thermal efficiency of the collectors and cost to produce the required amount of heated water was small. The accumulating heated water collector system effectively used solar energy during the day, and the other types effectively used solar energy in the evening. The best method of control to minimize outlet-temperature fluctuations in the heated water and to make the tank-temperature approach the usage temperature was control method (2) (i.e., control with solar radiation).
KW - Cost
KW - Optimal operation control
KW - Optimal system design
KW - Solar thermal collector
KW - Temperature
KW - Thermal efficiency
UR - http://www.scopus.com/inward/record.url?scp=84911904896&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84911904896&partnerID=8YFLogxK
M3 - Conference contribution
SP - 129
EP - 139
BT - OPT-i 2014 - 1st International Conference on Engineering and Applied Sciences Optimization, Proceedings
PB - National Technical University of Athens
ER -