Performance analysis of two condenser models used for solar energy-assisted water distillation

Abstract

An experimental and modeling comparison of optimal running conditions and energy consumption of shell and tube condenser and surface condenser which can be used for water distillation in conjunction with a Parabolic Trough Collector (PTC)-type solar energy system is reported in this research paper. A PTC of dimensions 4.5 m × 4.8 m with the aperture area of 20.3 m2 was used in this study. Further, 15 number of modeling equations were utilized in this research. The calculated distilled water production capacity of the system was 55.6 l /day, by considering solar irradiation, sun available time, and solar energy harnessing system efficiency as 0.9 kW m−2, 4 h, and 50%, respectively. The cooling water input temperature was about 32 °C throughout the research period. For the surface condenser, the optimum flow rate was found to be 8.5 l /min while it was not possible to find any optimum or safe running flow rate for the traditional condenser up to the flow rate of 60 l /min, due to the occurrence of sudden vacuumed pulses of about 85 Hg mm. These vacuumed pulses arose due to pressurized steam pushing out the blocked condensate layer from tubes. The traditional condenser was modified by inclining it by 5° to horizontal and dipping the condensate outlet in a water bath. With that modification, the optimum flow rate was found to be 30 l /min. The performance of surface condenser, the production rate of the condensate was 4% higher, and the consumption of the cooling water was 28% lower as compared to the modified traditional condenser. The effect of its sump level on the performance was also studied, and it revealed the condensation level in the sump of the surface condenser should be maintained in between ¼ and ¾ from the total height of the sump.