In –Situ Measurements of the Performance of Thermosyphon Solar Water Heating Systems in Libya

1. In –Situ Measurements of the Performance of Thermosyphon Solar Water Heating Systems in Libya Dr. M Abdunnabi Center for Solar Energy Research and Studies CSERS ICRE 2010

2. Presentation Structure • Electricity Generation and Distribution in Libya • Electricity Distribution in the Residential sector • Potential of Solar Energy • Solar water heaters in Libya • System and measurements • Results and Discussion • Conclusion CSERS ICRE 2010

3. Electricity Generation and Distribution in Libya • The electricity produced • 28,666 GWh • -The electricity Sold • 18,451 GWh The electricity distribution, 2008 CSERS ICRE 2010

4. Electricity consumption in Residential sector - Hot water consume about 12% of total national electricity 3440 GWh CSERS ICRE 2010

5. Average yearly global solar radiation contours map of Libya (kW/m2/day) CSERS ICRE 2010

6. Solar Water Heaters in Libya • Excellent Solar Energy Resources • There is only about 3000 SWH systems installed in Libya due to: • Cheap Electric WH and electricity unit • High capital investment of SWH • Lack of environmental awareness • No clear and systematic policy CSERS ICRE 2010

7. Recently,… There is a plan to build over 250,000 residential building by 2012 New Laws have come into force that mandate the installation of SWH in new Residential buildings built by the government. Therefore,… There is a risk that poorly performing, low cost systems might enter the market and damage the image of SWH systems CSERS ICRE 2010

8. This paper gives idea about poor systems according to Libyan environment. The current study is a part from a, …. Project is carried out by CSERS to install 100 SWH in residential building Some of this systems were equipped with full instruments to evaluate their thermal performance CSERS ICRE 2010

9. System Specifications • Solar Collector • Flat plate fin and tube type (copper) • Area 2.9 m2 • Semi-selective coating • Storage tank • Capacity 210 liters • Horizontal position • Shell and tubes heat exchanger • Auxiliary electric heater is 3.6 kW • No of People in the house • 4 in week days • 6 in week ends CSERS ICRE 2010

10. Measuring parameters and instruments CSERS ICRE 2010

11. Sample of Recorded Data CSERS ICRE 2010

12. Sample of Recorded Data CSERS ICRE 2010

13. Annual normalized hot water consumption CSERS ICRE 2010

14. Mean monthly average values of inlet, outlet and ambient temperatures CSERS ICRE 2010

15. Monthly average daily radiation on collector plan 6.35 kWh/m2/day Ave : 5.83 kWh/m2/day 5.01kWh/m2/day CSERS ICRE 2010

16. Calculations: - Solar Fraction - Conversion efficiency CSERS ICRE 2010

17. Solar Fraction and Thermal Conversion Efficiency CSERS ICRE 2010

18. Some Remarks • The average hot water consumption over a year was 144 Liters per day, which is less than the storage tank volume. • The average withdrawal temperature was 46.6 °C • The largest amount of HW consumed was in winter season with 214 lit/day • The smallest amount of HW consumed was in summer season with 73 lit/day • The annual solar fraction is 55.8 %, and in winter season was 31.6% • The maximum thermal energy conversion efficiency was only 38.5%

19. Comparison with another System

20. Conclusion • Care should be taken to prevent bad performing systems from entering the Libyan market • Systems should be designed (Sized) according to the Libyan criteria of weather condition, load volume and load pattern. • The study has shown that morning HW consumption represents an essential part of the total HW consumption, therefore, the storage tank should be well insulated to save HW for next day use • Systems with vertical tanks and open loops perform better than systems with horizontal tanks and closed loops

21. Thanks for Your attentions !! CSERS ICRE 2010