Heat transfer coefficient and thermal losses of solar collector and Nusselt number correlation for rectangular solar air heater duct with longitudinal fins hold under the absorber plate

2014 ◽  
Vol 50 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Foued Chabane ◽  
Noureddine Moummi ◽  
Djamel Bensahal ◽  
Abdelhafid Brima
2018 ◽  
Vol 8 (01) ◽  
Author(s):  
Ambreesh Prasad Shukla ◽  
Rakesh Kushwaha ◽  
Bhupendra Gupta ◽  
Anand Bisen

Solar energy has emerged as one of the alternate to conventional sources of energy. Solar air heaters are one of the important devices to utilize solar energy. But, poor heat transfer coefficient is one of the major problem in solar air heater. In this research article, an attempt is made to increase heat transfer coefficient of solar air heater by putting Hollow bodies over the absorber plate. These resulted in increase in heat transfer coefficient, efficiency and increase in outlet temperature of air simultaneously


Author(s):  
Mohammad S. Saidi ◽  
Firooz Rasouli ◽  
Mohammad R. Hajaligol

Heat transfer coefficient of packed beds of shredded materials such as biomass fuels at low Peclet numbers is of interest. Due to the dependence of flow distribution on particle shape, the application of the Nusselt number correlation of packed bed of spherical particles overestimates the rate of heat transfer. This discrepancy is even more pronounced due to channeling effect at low Peclet numbers. Here, based on applying a pore submodel and combining the numerical simulation and experimental results of a cylindrical packed bed, a new correlation is derived for apparent Nusselt number of the packed bed of shredded materials. The correlation is approximated by a power law formulation for Pecelt < 25. The Nusselt number calculated from this correlation is in a good agreement with other experimental data.


Author(s):  
Kamlesh Sahu ◽  
◽  
Gyaneshwar Sanodiya ◽  

Solar air heaters are placed on farms to provide heat for the drying of grain and crop harvesting and harvesting. The results of the thermal study showed that solar air heaters are capable of providing a sufficient increase in air temperature under the majority of crop drying circumstances studied. The restricted thermal capacity of air, as well as the low heat transfer coefficient between the absorber plate and the air flow via the ducting system, both contribute to the overall thermal efficiency of solar air heaters. Solar air heaters must be more efficient in order to be more affordable. This may be accomplished by increasing the heat transfer coefficient between the absorber plate and the air flow passing through the duct. More heat transfer coefficients can be increased by using either active or passive approaches. In most situations, it may be cost-effective to use solar air heaters and incorporate artificial roughness on the absorber plate. The rate of heat transmission from the solar air heater’s duct to the fluid flow may be increased by creating artificial roughness on the surface of the duct. The study focused on several roughness element geometries for solar air heater ducts, and the results indicated that there is a link between the two. This paper attempts to find ways to artificially increase the heat transfer capacity of solar air heaters’ ducts by using element geometries which have been utilised in solar air heaters’ heat transfer devices.


Sign in / Sign up

Export Citation Format

Share Document