Optimal Control of Mass Flow Rates in Flat Plate Solar Collectors

1981 ◽  
Vol 103 (2) ◽  
pp. 113-120 ◽  
Author(s):  
R. C. Winn ◽  
C. B. Winn
Keyword(s):  
Optimal Control ◽  
Flat Plate ◽  
Flow Rate ◽  
State University ◽  
Colorado State University ◽  
Collector Efficiency ◽  
The Difference ◽  
Flat Plate Collector ◽  
Solar House ◽  
Bang Bang Control

The optimal flat plate collector fluid flow rate is determined for several combinations of objective functions and system models. The method of implementing the control strategy for one of the problems considered, that which maximizes the integral of the difference between the collected solar power and fluid moving power, is described. The performance of the solar energy collection system in Solar House II at Colorado State University using this optimal controller is discussed and compared with the same system using bang-bang control. In addition, the dependence of the collector efficiency factor on flow rate is considered and its effect on the optimal control is determined.

Energy and Exergy Analysis of Marquise Shaped Channel Flat Plate Solar Collector Using Al2O3–Water Nanofluid and Water

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Sahil Arora ◽  
Geleta Fekadu ◽  
Sudhakar Subudhi
Keyword(s):  
Flat Plate ◽  
Flow Rate ◽  
Volume Fraction ◽  
Pure Water ◽  
Maximum Energy ◽  
Working Fluid ◽  
Absorber Plate ◽  
Energy And Exergy ◽  
Aluminum Plates ◽  
Flat Plate Collector

The present study deals with the experimental performance of a Marquise shaped channel solar flat-plate collector using Al2O3/water nanofluid and base fluid (pure water). The experimental setup comprises a special type of solar flat plate collector, closed working fluid systems, and the measurement devices. The absorber plate is made of two aluminum plates sandwiched together with Marquise-shaped flow channels. The volume fraction of 0.1% of Al2O3/water nanofluid is used for this study. The various parameters used to investigate performance of the collector energy and exergy efficiency are collector inlet and outlet fluid temperatures, mass flow rate of the fluid, solar radiation, and ambient temperature. The flow rate of nanofluid and water varies from 1 to 5 lpm. The maximum energy efficiencies attained are 83.17% and 59.72%, whereas the maximum exergy efficiencies obtained are 18.73% and 12.29% for the 20 nm—Al2O3/water nanofluids and pure water, respectively, at the flow rate of 3 lpm. These higher efficiencies may be due to the use of nanofluids and the sophisticated design of the absorber plate with the Marquise shaped channel.

An Analytic Model of Stratification for Liquid-Based Solar Systems

1986 ◽  
Vol 108 (2) ◽  
pp. 105-110 ◽  
Author(s):  
K. DenBraven
Keyword(s):  
Temperature Distribution ◽  
Storage Temperature ◽  
Direct Calculation ◽  
Hot Water ◽  
Forced Flow ◽  
State University ◽  
Colorado State University ◽  
Liquid Storage ◽  
System Data ◽  
Solar House

Accurate modelling of solar air or liquid heating, cooling, or domestic hot water systems with storage generally requires an accounting of the stratification within such storage. Overall system performance may be significantly affected by the storage temperature distribution. Most current stratification models utilize a finite difference scheme for solution to the general equations. An analytic method to determine the temperature distribution has been derived for liquid storage within a solar system. In liquid storage, it is assumed incoming fluid enters at the location with the temperature closest to its own. Hence, the solution requires the possibility of a region within storage where there is no forced flow. In addition, ther may be collector loop flow, load loop flow, or both concurrently. Each of these cases has different boundary conditions, and each must be solved separately. Comparisons of the resulting calculations with system data for the Colorado State University Solar House I show good agreement. This suggests that inclusion of an analytic stratification model within a system simulation may be useful by allowing direct calculation of temperatures in stratified storage.

Relation between Collector Efficiency Factor and the Centre to Centre Distance of Absorber Tubes of Solar Flat-Plate Collector

2014 ◽  
Vol 592-594 ◽  
pp. 2404-2408 ◽  
Author(s):  
Sunita Meena ◽  
Chandan Swaroop Meena ◽  
V.K. Bajpai
Keyword(s):  
Solar Radiation ◽  
Solar Energy ◽  
Flat Plate ◽  
Special Kind ◽  
Radiation Energy ◽  
Efficiency Factor ◽  
Energy Gain ◽  
Absorber Plate ◽  
Collector Efficiency ◽  
Flat Plate Collector

Solar energy collectors are a special kind of heat exchangers that transform solar radiation energy to internal energy of the transport medium. The major component of any solar system is the solar collector. This is a device which absorbs the incoming solar radiation, converts it into heat, and transfers this heat to a fluid (usually air, water, or oil) flowing through the collector. The measurement of the flat plate collector performance is the collector efficiency. The collector efficiency is the ratio of the useful energy gain to the incident solar energy over a particular period of time. The useful energy gain is strongly depends on the collector efficiency factor and this factor directly influenced by few parameters i.e. the centre to centre distance of absorber tubes W , thickness of absorber plate δ and heat loss coefficient UL. This paper has been focused on the relation between W with collector efficiency factor of serpentine tube solar flat-plate collector. This study shows that if we increase the W then Fˈ decreases.

scholarly journals Particle Optimization of Ceo2/Water Nanofluids in Flat Plate Solar Collector

2019 ◽  
Vol 9 (2) ◽  
pp. 1467-1474 ◽  
Keyword(s):  
Flat Plate ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Solar Collector ◽  
Volume Concentration ◽  
Particle Volume ◽  
Wide Range ◽  
Flat Plate Solar Collector ◽  
Flat Plate Collector

The present research focuses on the role of CeO2/water nanofluid for estimating the performance of flat plate solar collector in respect of energetic and exergetic performance. Based on our experimental findings on varying mass flow rate, the present analysis focuses on a wide range of concentrations to find optimum volume concentration for which thermal performance is maximum. CeO2/water nanofluid exhibits high thermal conductivity improvement (~41.7%at 1.5% volume concentration) and comparatively lower dynamic viscosity. Performance evaluation of flat plate collector is based on first law analysis and qualitative nature of energy flow based on second law analysis. Experiments indicate that for~1.0% particle volume concentration at a mass flow rate of 0.03 kg/s, maximum collector efficiency is obtained up to 57.1% instead of water as the base fluid. Exergetic efficiency observed 84.6%at optimum concentration (~1.0% particle volume) of nanofluid at0.01 kg/s flow rate.

scholarly journals Performance enhancement studies in a thermosyphon flat plate solar water heater with CuO nanofluid

2017 ◽  
Vol 21 (6 Part B) ◽  
pp. 2757-2768 ◽  
Author(s):  
Anin Dasaien ◽  
Natarajan Elumalai
Keyword(s):  
Flat Plate ◽  
Performance Enhancement ◽  
Working Fluid ◽  
Efficiency Enhancement ◽  
Water Heater ◽  
Ansys Fluent ◽  
Collector Efficiency ◽  
Cfd Analyses ◽  
Flat Plate Collector ◽  
Solar Rays

Experiments were conducted on a thermosyphon type flat plate collector, inclined at 45?, for water heating application. Water and water based nanofluids were used as absorber fluid to gain heat from solar rays incident on the flat plate col-lector. Nanofluids were prepared by adding CuO nanoparticles of 40-50 nm size to the base fluid at 0.1, 0.2, 0.3, and 0.5 wt% (?). The hot absorber fluid was made to circulate in the shell side of a heat exchanger, placed at the top of the flat plate collector, where utility water was circulated inside a helically coiled Cu tube. Temperatures at strategic locations in the flat plate collector, working fluid, utility water inlet and outlet were measured. The nanofluid increases the collector efficiency with increasing ?. A highest efficiency enhancement of 5.7% was observed for the nanofluid with ? = 0.2 having a mass flow rate of 0.0033 kg/s. The 3-D, steady-state, conjugate heat transfer CFD analyses were carried out using the ANSYS FLUENT 15.0 software. Theoretically estimated buoyancy induced fluid flow rates were close with the CFD predictions and thus validates the computational methodology.

scholarly journals Experimental Evaluation of a Flat Plate Solar Collector Under Hail City Climate

2018 ◽  
Vol 8 (2) ◽  
pp. 2750-2754
Author(s):  
N. Ben Khedher
Keyword(s):  
Flat Plate ◽  
Flow Rate ◽  
Solar Collector ◽  
Weather Conditions ◽  
Water Heater ◽  
Optimum Flow Rate ◽  
Water Heaters ◽  
Flat Plate Solar Collector ◽  
Flat Plate Collector ◽  
Solar Water Heaters

Flat plate solar water heaters are widely used for water heating in low-temperature residential applications. In this paper the thermal performance of a solar flat plate water heater under Hail weather conditions (latitude 27°52΄N longitude ‎41°69΄E) was experimentally investigated. Fluid was circulated through the imbedded copper tubes in the flat plate collector and inlet and outlet temperatures of the fluid were noted at five minute intervals. The experimental-time was between 9:00AM-15:00PM. A study was carried out experimentally to present the efficiency curves of a flat plate solar collector at different flow rates. ASHRAE standard 93-2003 was followed for calculation of instantaneous efficiency of solar collector. Result shows that the flow rate of the circulating fluid highly influence the thermal efficiency of the solar collector. Optimum flow rate of 2.5L/min leads to maximum collector efficiency.

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