Optimal thermohydraulic performance of artifically roughened solar air heaters
Abstract
The heat transfer coefficient of solar air heaters can be increased by providing artificial roughness on the bottom of the absorber plate, leading to higher collection efficiency. Inclusion of artificial roughness, however, results in a higher friction factor and consequently a higher pumping power is required. Results show that both the Nusselt number and friction factor increase with increasing relative roughness height and decrease with increasing relative roughness pitch, but not in direct proportions. Optimization of the roughness and flow parameters (p/e, e/D, Re) to maximize heat transfer while keeping friction losses minimum was attempted. It has been found that a particular value of roughness Reynolds number (e{sup +} = e/D {radical}{ovr f/2Re}), always corresponds to optimum thermohydraulic conditions in the range of parameters investigated. On this basis design curves have been developed that give the optimal thermohydraulic performance combination of these parameters.
- Authors:
-
- Univ. of Roorkee (India)
- Publication Date:
- OSTI Identifier:
- 5109254
- Resource Type:
- Journal Article
- Journal Name:
- Solar Energy (Journal of Solar Energy Science and Engineering); (United States)
- Additional Journal Information:
- Journal Volume: 47:2; Journal ID: ISSN 0038-092X
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 14 SOLAR ENERGY; SOLAR AIR HEATERS; HEAT TRANSFER; DESIGN; ENERGY CONSUMPTION; EQUATIONS; FLAT PLATE COLLECTORS; FLOW RATE; FRICTION FACTOR; HYDRAULICS; LAMINAR FLOW; NUSSELT NUMBER; OPTIMIZATION; PARAMETRIC ANALYSIS; PERFORMANCE; PUMPING; ROUGHNESS; SOLAR ABSORBERS; THERMAL EFFICIENCY; THERMODYNAMICS; TRANSITION FLOW; TURBULENT FLOW; AIR HEATERS; EFFICIENCY; ENERGY TRANSFER; EQUIPMENT; FLUID FLOW; FLUID MECHANICS; HEATERS; MECHANICS; SOLAR COLLECTORS; SOLAR EQUIPMENT; SURFACE PROPERTIES; 140901* - Solar Thermal Utilization- Space Heating & Cooling
Citation Formats
Prasad, B N, and Saini, J S. Optimal thermohydraulic performance of artifically roughened solar air heaters. United States: N. p., 1991.
Web. doi:10.1016/0038-092X(91)90039-Y.
Prasad, B N, & Saini, J S. Optimal thermohydraulic performance of artifically roughened solar air heaters. United States. https://doi.org/10.1016/0038-092X(91)90039-Y
Prasad, B N, and Saini, J S. 1991.
"Optimal thermohydraulic performance of artifically roughened solar air heaters". United States. https://doi.org/10.1016/0038-092X(91)90039-Y.
@article{osti_5109254,
title = {Optimal thermohydraulic performance of artifically roughened solar air heaters},
author = {Prasad, B N and Saini, J S},
abstractNote = {The heat transfer coefficient of solar air heaters can be increased by providing artificial roughness on the bottom of the absorber plate, leading to higher collection efficiency. Inclusion of artificial roughness, however, results in a higher friction factor and consequently a higher pumping power is required. Results show that both the Nusselt number and friction factor increase with increasing relative roughness height and decrease with increasing relative roughness pitch, but not in direct proportions. Optimization of the roughness and flow parameters (p/e, e/D, Re) to maximize heat transfer while keeping friction losses minimum was attempted. It has been found that a particular value of roughness Reynolds number (e{sup +} = e/D {radical}{ovr f/2Re}), always corresponds to optimum thermohydraulic conditions in the range of parameters investigated. On this basis design curves have been developed that give the optimal thermohydraulic performance combination of these parameters.},
doi = {10.1016/0038-092X(91)90039-Y},
url = {https://www.osti.gov/biblio/5109254},
journal = {Solar Energy (Journal of Solar Energy Science and Engineering); (United States)},
issn = {0038-092X},
number = ,
volume = 47:2,
place = {United States},
year = {Tue Jan 01 00:00:00 EST 1991},
month = {Tue Jan 01 00:00:00 EST 1991}
}