scholarly journals Analysis on Heat Transmission and Fluid Flow Attributes in Solar Air Accumulator Passage with Diverse Faux Jaggedness Silhouettes on Absorber Panel

2019 ◽  
Vol 8 (5S3) ◽  
pp. 32-41 ◽  
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Optimum Shape ◽  
Solar Air Heater ◽  
Artificial Roughness ◽  
Heat Transmission ◽  
Number Range ◽  
Elliptical Shape ◽  
Shape Pattern

There is a necessity to investigate the heat transmission and fluid cascade peculiarities of solar air convectors using varying faux irregular surface and shapes on absorber sheet, so that the solar devices utilize maximum amount of available solar radiated heat energy during day time. These artificial roughness shapes are use for the enhancement of thermal performance. This need arises from the fact that the heat circulation and liquid cascade trait have been investigated by the previous investigators only for the cases that differ considerably from those relevant to solar air brazier having different screen matrix placed in the planes parallel to the flow direction and that the radiant energy being absorbed in depth. In our present research paper we investigating experimentally the behavior of artificial irregularities located over absorber platter of solar air heater vessel of varying shapes like trapezoidal, sin wave, rectangular, alternative elliptical shape pattern etc, with different Reynolds Number range 4000 to 24000, mass flow rate on Nusselt Number and Friction Factor and also find the suitable optimum shape for heat transmission enhancement. The results indicated the best heat transfer enhancement results for the alternative elliptical shape pattern among other artificial roughness with range of 0.0786kg/s – 0.475kg/s mass flow rate with thermal efficiency near about 78%.

Mass Flow Rate Measurements: From Hydrodynamic to Free Molecular Regime

2008 ◽  
Author(s):  
Timothe´e Ewart ◽  
Irina A. Graour ◽  
Pierre Perrier ◽  
J. Gilbert Me´olans
Keyword(s):  
Mass Flow Rate ◽  
Knudsen Number ◽  
Mass Flow ◽  
Flow Rate ◽  
Stationary Flow ◽  
Small Mass ◽  
Accommodation Coefficient ◽  
Navier Stokes ◽  
Number Range ◽  
Free Molecular Regime

An experimental investigation in a single silica microtube in isothermal stationary flow for various gases is made from the hydrodynamic to the near free molecular regime to study the reflection/accommodation process at the wall. This kind of investigation requires, more than other Micro-Electro-Mechanical-Systems (MEMS) experiments, a powerful experimental platform to measure very small mass flow rate. A global analytic expression, based on the Navier-Stokes (NS) equations with second order boundary conditions, is used to yield the Tangential Momentum Accommodation Coefficient (TMAC) in 0.003–0.3 Knudsen number range. Otherwise, the experimental results of the mass flow rate is compared with theoretical values calculated from kinetic approaches using variable TMAC as fitting parameter over the 0.3–30 Knudsen number range. Finally, whatever the theoretical approach the TMAC values obtained from the different gas-surface pairs are rather close one to other, but the TMAC values seem decreasing when the molecular mass increases.

scholarly journals Thermal and Cost Analysis of a Multi-Pass Solar Air Heater with Reversed Absorber and Reflector

2020 ◽  
pp. 141-146
Keyword(s):  
Cost Analysis ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Cost Effective ◽  
Solar Air Heater ◽  
Constant Mass ◽  
Air Heater ◽  
Effectiveness Model ◽  
Solar Intensity

Solar air heater is a major component of solar dryer. A model of multi pass solar air heater (MPSAH) with reversed absorber and reflector was developed. Exhaustive Study over the performance of MPSAH with and without reversed absorber and cost analysis was done. The performance curves show the effect of solar intensity on MPSAH with and without reversed absorber at constant mass flow. It was observed that the thermal efficiency of MPSAH is depending on solar intensity and losses when mass flow rate remain constant. At constant mass flow rate 26.90 gm/sec, the collector efficiency increased by 9% at average solar intensity 457w/m². Theoretical and experimental analysis showed close agreement. In addition the cost-effectiveness model has been used to examine the performance MPSAH with and without reverse absorbers. The air heaters annual cost (AC) estimation and annual power acquirement (AG) was analyze. The result is evidence for that multi-pass solar air heater with reverse absorbers and reflector is more cost-effective than multi-pass solar collectors without reverse absorber.

scholarly journals Selecting the Optimal Configuration for a Solar Air Heater Using the Grey–Taguchi Method

Processes ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 317
Author(s):  
Raheleh Nowzari ◽  
Nima Mirzaei ◽  
Kiyan Parham
Keyword(s):  
Taguchi Method ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Thermal Performance ◽  
Solar Collector ◽  
Optimal Configuration ◽  
Solar Air Heater ◽  
Double Pass ◽  
Grey Taguchi

In this study, a typical Grey–Taguchi method has been applied in order to select the optimal configuration of a solar air heater to achieve optimum performance. The analysis is performed for different system configurations in terms of collector type, mass flow rate, and cover type. The Grey–Taguchi method, which requires the minimum possible numbers of the demanded experiments for accomplishing a robust statistical decision for a given experimental problem, has been employed, and temperature difference and thermal performance have been used as the two main criteria. It is found that by considering the temperature difference criterion, at a mass flow rate of 0.011 kg/s, the best configuration is the double-pass solar collector owning a one-fourth pierced Plexiglas cover with a distance of 60 mm between the centers of the holes. On the other hand, by considering the thermal performance as the criterion, the best configuration at a mass flow rate of 0.032 kg/s is found to be the double-pass solar collector holding a half-pierced Plexiglas cover and a distance of 60 mm distance between the centers of the holes. Finally, once both factors are taken into consideration, the optimal configuration suggested by the method is the double-pass collector with a one-quarter pierced Plexiglas cover. The method also suggests keeping a 30 mm distance between the centers of the holes and applying 0.032 kg/s of the mass flow rate to achieve the highest performance.

scholarly journals Modeling and PSO optimization of Humidifier-Dehumidifier desalination

2018 ◽  
Vol 7 (1) ◽  
pp. 59 ◽  
Author(s):  
Mohammad Hossein Ahmadi ◽  
Mohammad Ali Afshar ◽  
Ali Naseri ◽  
Mokhtar Bidi ◽  
H. Hadiyanto
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Temperature Difference ◽  
Cooling Water ◽  
Decision Variable ◽  
Solar Air Heater ◽  
Air Heater ◽  
Output Ratio ◽  
Optimum Productivity

The aim of this study is modeling a solar-air heater humidification-dehumidification unit with applying particle swarm optimization to find out  the maximum gained output ratio with respect to the mass flow rate of water and air entering humidifier, mass flow rate of cooling water entering dehumidifier, width and length of solar air heater and terminal temperature difference (TTD) of dehumidifier representing temperature difference of inlet cooling water and saturated air to dehumidifier as its decision variable. A sensitivity analysis, furthermore, is performed to distinguish the effect of operating parameters including mass flow rate and streams’ temperature. The results showed that the optimum productivity decreases by decreasing the ratio of mass flow rate of water entering humidifier to air ones.Article History: Received: July 12th 2017; Revised: December 15th 2017; Accepted: 2nd February 2018; Available onlineHow to Cite This Article: Afshar, M.A., Naseri, A., Bidi, M., Ahmadi, M.H. and Hadiyanto, H. (2018) Modeling and PSO Optimization of Humidifier-Dehumidifier Desalination. International Journal of Renewable Energy Development, 7(1),59-64.https://doi.org/10.14710/ijred.7.1.59-64

scholarly journals Experimental Study of the Slit Spacing and Bed Height on the Thermal Performance of Slit-Glazed Solar Air Heater

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Seyyed Mahdi Taheri Mousavi ◽  
Fuat Egelioglu
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Ambient Air ◽  
Solar Air Heater ◽  
Outlet Temperature ◽  
Flow Rates ◽  
Air Mass ◽  
Bed Height ◽  
Mass Flow Rates

The thermal performances of three slit-glazed solar air heaters (SGSAHs) were investigated experimentally. Three SGSAHs with different bed heights (7 cm, 5 cm, and 3 cm) were fabricated with multiple glass panes used for glazing. The length, width, and thickness of each pane were 154 cm, 6 cm, and 0.4 cm, respectively. Ambient air was continuously withdrawn through the gaps between the glass panes by fans. The experiments were conducted for four different gap distances between the glass panes (0.5 mm, 1 mm, 2 mm, and 3 mm) and the air mass flow rate was varied between 0.014 kg/s and 0.057 kg/s. The effects of air mass flux on the outlet temperature and thermal efficiency were studied. For the SGSAH with bed height of 7 cm and glass pane gap distance of 0.5 mm, the highest efficiency was obtained as 82% at a mass flow rate of 0.057 kg/s and the air temperature difference between the inlet and the outlet (∆T) was maximum (27°C) when the mass flow rate was least. The results demonstrate that for lower mass flow rates and larger gaps, the performance of SGSAH with a bed height of 3 cm was better compared to that of others. However, for higher mass flow rates, the SGSAH with 7 cm bed height performed better.

scholarly journals Effects of Louvered Parameters on Exergetic Performance of Louvered Finned Solar Air Heater

2021 ◽  
Vol 39 (5) ◽  
pp. 1649-1658
Author(s):  
Subhash Chand ◽  
Prabha Chand
Keyword(s):  
Heat Transfer ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Operating Conditions ◽  
High Mass ◽  
Solar Air Heater ◽  
Air Heater ◽  
Pitch Ratio ◽  
Exergy Performance

The aim of the present study to improve the performance of solar air heater because of low thermo-physical properties of air. In the current work, an attempt has been made to improve the performance of the heater by employing louvered fins to the absorber plate, as it not only enhances heat transfer coefficient but also improve heat transfer area. The effect of exergy performance on the geometrical parameters of louvered fin i.e., louvered angle, louvered pitch and louvered length has been studied and analyzed. The results are compared to plane solar air heater (PSAH) to evaluate the effectiveness of louvered finned solar air heater (LFSAH). The exergy efficiency of LFSAH is comparatively higher for all the operating conditions except for higher mass flow rate where it may even go below that of PSAH; possibly due to the higher pressure drop and more loss of exergy at high mass flow rate. In addition, the results conclude that for louvered parameters viz., louvered angle 20°, fin pitch to louvered pitch ratio 0.75 and louvered length to louvered pitch ratio 1.25, high exergy performance of SAH is obtained as compared to other louvered parameter values.

scholarly journals Performance Analysis of Solar Desalination System for Improved Productivity by using Waste Heat of Household Chimney

2020 ◽  
Vol 8 (6) ◽  
pp. 3221-3225
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Brackish Water ◽  
Potable Water ◽  
Water Yield ◽  
Solar Air Heater ◽  
Water Tank ◽  
Conventional System ◽  
Air Heater

This work deals with the analysis of the proposed innovative humidification-dehumidification (HD) desalination unit in which waste hot air of kitchen chimney has been used for heating brackish water. The proposed system is configured with solar air heater also, thus both heated air and heated water has been used to improve the water yield of desalination unit compared to conventional system. Mathematical modeling of propose unit based on energy balance of flat plate air heater, humidifier, dehumidifier and brackish water tank has been used to evaluate the effect of operating condition. Potable water yield found to increase (with highest productivity of 6.5 kg/day) when mass flow rate of process air increases from 0.6 kg/min to 3 kg/min. Strong dependency of water mass flow rate has also been found as productivity increases (with maximum value of 6.7 kg/day and 7.5 kg/day) by increasing the mass flow rate of brackish water in humidifier and cold water in dehumidifier respectively. The higher initial temperature of brackish water also found beneficial as it increases productivity. Finally, the thermal performance of desalination unit has been evaluated in terms of Gain in Output Ratio and comparison has been made with conventional system. The higher GOR of the proposed system ensures the better utilization of thermal energy in potable water production.

scholarly journals Mathematical Modelling of Single Glazed and Double Glazed Solar Air Heater

2021 ◽  
Vol 10 (3) ◽  
pp. 34-42
Author(s):  
Bhawna Agrawal ◽  
Pallavi Agrawal ◽  
Suman Agrawal
Keyword(s):  
Solar Radiation ◽  
Mathematical Modelling ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Winter Season ◽  
Solar Air Heater ◽  
Counter Flow ◽  
Heat Gain ◽  
Air Heater

This paper focuses on Mathematical Modelling of Single Glazed and Double Glazed Solar air heater (SAH) which is special kind of heat exchanger that transfers thermal energy from the solar radiation to the fluid flowing inside of the collector. The most potential applications of SAH is the supply of hot air for heating of buildings, to maintain a comfortable environment especially in the winter season, air preheating, desiccant refrigeration, and drying of vegetables, fruits, meat, textile and marine products. Solar radiation intensity is less in the morning that increase gradually till noon and again decrease from noon to evening. During simulations it is observed that the heat gain is directly proportional to the mass flow rate. It is maximum for the counter flow SAH and is least for transpired solar air heater. The efficiency of the SAH is directly proportional to mass flow rate. The thermal efficiency is maximum for the counter flow SAH, The useful heat gain increases is highest in the clear days of summer month particularly in the month of April-May and lowest in the cloudy days of winter month particularly in the month of December. The results are in conformation with theoretical aspects.

scholarly journals Numerical Simulation of Solar Air Heater using Paraffin Wax-Aluminum Compound as Phase Changing Material

2021 ◽  
Vol 3 (2) ◽  
pp. 49-55
Author(s):  
Atul Kumar ◽  
Prabhakar Bhandari ◽  
K.S. Rawat
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Paraffin Wax ◽  
Solar Air Heater ◽  
Outlet Temperature ◽  
Freezing Time ◽  
Aluminum Compound ◽  
Air Heater ◽  
Aluminium Powder

This paper presents a theoretical investigation of solar air heater using phase change material (PCM). PCM used in present configuration is homogenous mixture of paraffin wax with Aluminium powder. The purpose of using Aluminium powder with paraffin wax is to increase the thermal conductivity. PCM mixtures are encapsulated in cylinders and are used as solar absorbers. Using MATLAB program, the effect of different parameters is studied. It has been observed that with increase in mass flow rate, air outlet temperature decreases and freezing time of cylinder decreases. However, at constant mass flow rate, with increase in cylinder radius, air temperature decreases and while freezing time increase sharply. The different parameters have  to be chosen such that performance of solar air heater can be optimized.

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