초록

Record 측정기준과 수준
세계최고기록 - 없음
KAIST의 초기기록 - 시작 단계
최종 목표치(2014) - 전기효율10~20%, 열효율 50~70%
달성된결과치(2014) - 전기효율 16%, 열효율 48%

Abstract ▼

4. Research Results
(1) Outcome results
4.1 Verification of the solar-tracking system
The experimental azimuthal and elevation angles registered at the Korea Advanced Institute of Science and Technology (KAIST) were compared with the actual values obtained from the Korea Astronomy and Space

4. Research Results
(1) Outcome results
4.1 Verification of the solar-tracking system
The experimental azimuthal and elevation angles registered at the Korea Advanced Institute of Science and Technology (KAIST) were compared with the actual values obtained from the Korea Astronomy and Space Science Institute (KASSI) [5-7]. The average error between 9:00 am and 5:00 pm was within 0.04°, as shown in Fig. 4. According to these results, the solar-tracking algorithm used for the heating system was accurate.
The solar-tracking system underwent extensive testing for this study. Figure 5 shows the transient motion of the heating system for every hour, on the hour. The right and left sides of each figure correspond to the eastward and westward directions, respectively. The solar sensor of the heating system moved from east to west while tracking the trajectory of the sun. After sunrise, the solar sensor searched for the sun automatically. Tracking of the sun was also initiated after the disappearance of cloud cover. After sunset, the solar sensor was shut down automatically.
4.2 Electrical and thermal efficiency
Here, q”irr represents the energy density, A0 is the solar cell area, ṁ represents the mass of the water, Cp is the specific heat capacity of the water, Tin is the absorber inlet temperature, and Tout is the absorber outlet temperature of the water.
The total energy (Q1), maximum power (P), collected heat (Q2), electrical efficiency (nel), and thermal efficiency (nth) are given below:
(수식)
4.3 Validation of the heating system
Figure 6 shows a validation of the heating system using solar cells consisting of different thermal absorbers. The solar sensor located on the upper side of the heating system moved from east to west while tracking the trajectory of the sun.
① single copper pipe
② double copper pipe
③ 800mm length of heat-pipe
④ 900mm length of heat-pipe
the bottom left and right corners, respectively. On the other hand, the inlet and outlet of thermal absorber using heat pipe were located at the top left and right corners, respectively.
The average electric efficiency using single copper pipe was 16.6% during the day, and the average thermal efficiency was 48.1%. Therefore, the proposed system had a total efficiency (electrical + thermal) of 64.7%. On average, changes in the electrical efficiency were minimal. Moreover, the thermal efficiency was constant, irrespective of time and outside temperature because the thermal absorber was insulated with glass wool.
The average electric efficiency using double copper pipe was 16.6% during the day, and the average thermal efficiency was 46.5%. Therefore, the proposed system had a total efficiency (electrical + thermal) of 63.1%. As there is no difference of thermal efficiency between single and double copper pipe, single copper pipe is more practical considering economic feasibility.
The average electric efficiency using 800mm length of heat pipe was 16.4% during the day, and the average thermal efficiency was 27.4%. Therefore, the proposed system had a total efficiency (electrical + thermal) of 43.8%.
The average electric efficiency using 900mm length of heat pipe was 16.6% during the day, and the average thermal efficiency was 27.6%. Therefore, the proposed system had a total efficiency (electrical + thermal) of 44.2%. As heat losses is generated in water tank due to the heat exchange, thermal efficiency using heat pipe decrease about 21% compared to copper pipe
(2) Further research required
By doing practical test, the generated electricity is grid-connected with KEPCO. Also, utilization of the air conditioning and heating in real-life can be available.
(3) Findings deserve to press

목차 Contents

• EEWS Research 2014 Final Report ... 1
• Summary (English) ... 2
• 국문 요약문 ... 4
• 1. Research Purpose ... 6
• 2. Research Target and Achievement ... 6
• 3. Research Method ... 7
• 3.1 Overall system ... 7
• 3.2 Solar tracking device ... 8
• 3.3 Control system ... 9
• 3.4 Fabrication Method ... 13
• 4. Research Results ... 19
• (1) Outcome results ... 19
• (2) Further research required ... 25
• (3) Findings deserve to press ... 25
• 5. Research Outcomes ... 26
• (1) Publication ... 26
• (2) Conference presentation ... 26
• (3) Patents ... 26
• (4) Creation of New Big Project ... 27
• 6. Reference ... 27
• 1. 연구목적 ... 28
• 2. 연구목표와 성과 ... 28
• 3. 연구방법 ... 29
• 3.1 전체적인 시스템 ... 29
• 3.2 태양추적장치 ... 30
• 3.3 제어 시스템 ... 31
• 3.4 제작 방법 ... 34
• 4. 연구결과 및 고찰 ... 41
• (1) 연구결과 ... 41
• 5. 연구결과물 발표실적 ... 47
• (1) 논문 ... 47
• (2) 학회발표 ... 47
• (3) 특허 ... 47
• 6. 참고문헌 ... 48
• 끝페이지 ... 48