Study of Various Configurations of Hybrid PV/T System

In this study, an attempt has been made to evaluate the theoretical performance and evaluation of a hybrid PV/thermal (PV/T) collector based on dual heat extraction operation a function of climatic and design parameters. On the first hand, the different configurations of hybrid collectors are considered for the present study which are defined as unglazed PV/T air heaters, with and without tedlar, PVT hybrid water collector, in the second hand two configurations with dual extraction operation (water and air as heat removal fluid) are presented which are defined as dual PV/T model with tedlar, dual hybrid PV/T without tedlar. Analytical expressions for the temperatures of solar cells, back surface of the module, outlet air, and outlet water of those configurations have been derived. Numerical computations have been carried out for composite climate and the results for different configurations have been compared. Our results clearly show the direct impact of various parameters, in particular the solar radiation, ambient temperature, mass flow rate on the variation of outlet and solar cell of the collector.

Energy and Economic Analysis of Curved, Straight, and Spiral Flow Flat-Plate Solar Water Collector

In this work, the solar water collector flow tube geometry is modified as curved and spiral to enhance the system’s performance. The investigation is carried out experimentally under the meteorological conditions of the Kovilpatti region (9°10 ′ 0 ″ N, 77°52 ′ 0 ″ E), Tamil Nadu, India. The flow pipes of the solar water heater are made of copper material which has higher thermal conductivity to recover the water heat as thermal energy. The influence of the mass flow rate (MF) on the flow pipes with respect to the surface temperature for various configurations of the flow tubes is investigated. The two MFs of 0.0045 kg/s and 0.006 kg/s are tested. The MF of 0.006 kg/s yields the maximum efficiency of 73% compared to the other MF. The straight, curved, and spiral tubes yielded the maximum efficiency of 58%, 62%, and 69%, respectively, at 0.0045 kg/s. Similarly, the MF of 0.006 kg/s obtained an efficiency of 62%, 65%, and 73% for straight, curved, and spiral flow tubes, respectively. The economics and exergy of the system are analyzed. The maximum exergy efficiency of the collector is estimated to be 32% for the MF of 0.0045 kg/s for the spiral flow collector, and for the 0.006 kg/s MF, the obtained exergy efficiency is 27% for the spiral flow water heater. The economic analysis revealed that the expense is $0.0608 and $0.0512 worth of hot water produced for the domestic space heating.

Experimental investigation of the performance of a solar dryer integrated with solid desiccant coloums using water based solar collector for medicinal herb

This study is concerned with the analyses of performance on a solar dryer integrated with solid desiccant coloums using water based solar collector. The dryer consists of a solar water collector, two solid desiccant coloums, a water storage tank, two heat exchangers, an air heater, and a drying chamber. The dryer decreased the <em>Centella asiatica</em> L moisture content from 88.3% (wb) to 15.9% (wb) within 12 hours, with an average temperature and relative humidity of 45.4°C and 25.8%, respectively. The rate of moisture evaporation and the specific moisture evaporation rate were in the range of 0.001-1.762kg/h and 0.02-0.482 kg/kWh, with 0.594kg/h and 0.169kg/kWh in average values, respectively. The dryer efficiency was in the range of 0.62%-30.4%, with 15.4% in average value. The energy required for moisture evaporation and total energy input to the dryer were in the range of 26.9-1132.2W and 3638.0-4329.7W, with 601.8 W and 3967.4 W in average values, respectively. The efficiency of collector and the heat exchanger effectiveness were in the range of 38.1-50.5% and 65.1-79.7%, with 45.0% and 73.0% in average values, respectively. The result shows that the dryer is suitable for drying <em>Centella asiatica </em>L, this is due to the low temperature of drying air and high moisture evaporation rate.