Experimental Study of a Solar Air Heater With a New Arrangement of Transverse Longitudinal Baffles

2017 ◽  
Vol 139 (3) ◽  
Author(s):  
Afaq Jasim Mahmood
Keyword(s):  
Heat Transfer ◽  
Flow Rate ◽  
Thermal Efficiency ◽  
Air Flow ◽  
Maximum Temperature ◽  
Maximum Efficiency ◽  
Solar Air Heater ◽  
Air Flow Rate ◽  
Double Pass ◽  
Air Heater

This study presents a new design for improving the convection heat transfer coefficients of double-pass solar air heater. Three cases were described by using a different number of transverse baffles (three, five, and seven) in the lower channel of the collectors; steel mesh sheets were also used to enlarge the heat transfer area. All collectors have a space of 25 mm between its glass covers and a 50 mm depth of air channel. Furthermore, this work examined the effect of air flow rate and baffles number on device's thermal efficiency and outlet temperature. The experimental results indicate raises in the thermal efficiency as the air flow rate goes from 0.011 kg/s to 0.038 kg/s. A maximum efficiency of 68% was obtained from the case of seven baffles at the air flow rate of 0.038 kg/s. Moreover, the difference between collector's inlet and outlet temperatures, ΔT, indicated an inverse relationship with air flow rate. Thus, the results show ΔT increases as the air flow rate reduced. The maximum temperature difference recorded was 54 °C, which achieved using seven baffled solar air heater at 0.011 kg/s air flow rate in the middle of the day. It has also been found that thermal efficiency of double-pass solar air heater is greater than single-pass solar air heater, using same air flow rate and number of baffles. Finally, the pressure drop associated with increasing the number of baffles and air flow rate was deliberated.

scholarly journals Thermal Evaluation of a Double-Pass Unglazed Solar Air Heater with Perforated Plate and Wire Mesh Layers

2020 ◽  
Vol 12 (9) ◽  
pp. 3619
Author(s):  
Afaq Jasim Mahmood
Keyword(s):  
Flow Rate ◽  
Thermal Efficiency ◽  
Air Flow ◽  
Wire Mesh ◽  
Inlet Temperature ◽  
Solar Air Heater ◽  
Outlet Temperature ◽  
Air Flow Rate ◽  
Double Pass ◽  
Air Heater

In this study, an experimental outdoor investigation of the thermal efficiency and outlet air temperature was conducted on an unglazed, double-pass, solar air heater with a perforated absorber plate and packing wire mesh layers as a supplemental absorbent area. This was done to observe their effects on the thermal performance of the solar air heater. The double-pass collector was constructed with a bed height of 0.05 m, and a collection area of 1.5 m2. The height of the upper channel was fixed at 0.015 m to improve the thermal efficiency, and the outlet temperature at air flow rates between 0.003 and 0.018 kg/s. The collector was mounted with a slope of 42° facing south, to maximize the intensity of solar irradiance during winter. The effects of the air flow rate, ambient temperature, inlet temperature, outlet temperature, and solar intensity were experimentally investigated. The results showed that thermal efficiency could be improved by increasing the air flow rate, where the highest thermal efficiency achieved was 86% at 0.018 kg/s. However, the temperature difference was increased to a maximum value of 38.6 °C, when the air flow rate was decreased to 0.003 kg/s. Furthermore, the results demonstrated a significant improvement in the thermal efficiency and outlet temperature; and when compared with previous research, the experimental results and the predictions for the outlet temperature using the theoretical model agreed.

scholarly journals Performances of packed bed double pass solar air heater with different inclinations and transverse wire mesh with different intervals

2016 ◽  
Vol 20 (1) ◽  
pp. 175-183 ◽  
Author(s):  
Gnanadurai Sugantharaj ◽  
Kumar Vijay ◽  
Kalidasa Kulundaivel
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Thermal Efficiency ◽  
Packed Bed ◽  
Wire Mesh ◽  
Solar Air Heater ◽  
Double Pass ◽  
Air Heater ◽  
Collector Efficiency

Solar air heating is a technology in which the solar energy from the sun is captured by an absorbing medium and used to heat the air flowing through the heater. In this study, thermal performance of a double pass solar air heater has been investigated experimentally at different conditions. The experiments were conducted with different inclinations of the collector, with and without wire mesh vertically fixed at the second pass in transverse direction and with different mass flow rates. The effect of air mass flow rate, wire mesh pitch and collector inclination on temperature rise and thermal efficiency have been studied. Results show that efficiency increases with mass flow rate. For the same mass flow rate, the thermal efficiency increases with the decrease in the wire mesh pitch. The maximum daily average efficiency of air heater was 79.8% at 0.025 kg/s mass flow rate, 10 cm wire mesh gap and 9? collector inclination facing south. The highest collector efficiency was observed in solar air heaters with 10 cm wire mesh gap.

Experimental Investigation on the Heat Transfer of a Portable Forced-Convection Solar Air Heater

2010 ◽  
Author(s):  
Mohammad Fakoor Pakdaman ◽  
Pejman Zohorian Izadi ◽  
Mohammad Javadinia Azari ◽  
Amir Lashkari
Keyword(s):  
Forced Convection ◽  
Air Flow ◽  
Bottom Plate ◽  
Solar Air Heater ◽  
Air Flow Rate ◽  
Flow Conditions ◽  
Maximum Enhancement ◽  
Air Heater ◽  
Weather Changes ◽  
Plate Absorber

A cross-corrugated portable forced-convection solar air heater has been designed, fabricated, and developed. A wavelike bottom plate has been positioned crosswise to the air flow while rectangular baffles have been attached to the flat-plate absorber. The relative corrugation height, (e/Dh) ranges between 0.24 and 0.4, and relative baffles distance (l/L) varies between 0.21 and 0.48. The air flow rate in the heater duct has been varied in the range of 0.001 kgs−1 to 0.01kgs−1 (Reynolds number ranges from 350 to 3500), while other thermal specifications such as inlet, outlet, and plate temperatures have varied due to weather changes. Results of this study have been compared with those related to smooth ducts and other literatures, and the maximum enhancement in Nusselt number is observed to be approximately five times of that of the smooth duct under similar flow conditions. Finally, thermal efficiency of the device for different case studies has been determined and compared with other researches.

scholarly journals EXPERIMENTAL STUDY OF SOLAR AIR HEATER USING OF PHOTOVOLTAIC CELLS

2020 ◽  
Vol 4 (12) ◽  
pp. 103-106
Author(s):  
Deeksha Vishwakarma ◽  
Jyoti Kale
Keyword(s):  
Experimental Study ◽  
Forced Convection ◽  
Flow Rate ◽  
Storage System ◽  
Flat Glass ◽  
Photovoltaic Cells ◽  
Solar Air Heater ◽  
Outlet Temperature ◽  
Air Flow Rate ◽  
Air Heater

In this paper, we are studying about solar air heater. The solar air heater are consisting the several component such as flat glass, collector, D.C. fan, photovoltaic cells and electrical storage system. In this study we are achieving the various type of outlet temperature with the help of D.C. fan and various Mass air flow rate using of simple absorber trays forced convection.

Oxidation and Heat Transfer Studies in Graphite Channels: I. The Effect of Air Flow Rate on the C-O2and CO-O2Reactions

1962 ◽  
Vol 12 (1) ◽  
pp. 39-45 ◽  
Author(s):  
Donald G. Schweitzer ◽  
George C. Hrabak ◽  
Robert M. Singer
Keyword(s):  
Heat Transfer ◽  
Flow Rate ◽  
Air Flow ◽  
Air Flow Rate

scholarly journals Numerical Simulation and Optimization of Waste Heat Recovery in a Sinter Vertical Tank

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 385 ◽  
Author(s):  
Chenyi Xu ◽  
Zhichun Liu ◽  
Shicheng Wang ◽  
Wei Liu
Keyword(s):  
Heat Transfer ◽  
Power Consumption ◽  
Flow Rate ◽  
Heat Dissipation ◽  
Waste Heat ◽  
Air Flow ◽  
Particle Diameter ◽  
Exergy Destruction ◽  
Air Flow Rate ◽  
Simulation And Optimization

In this paper, a two-dimensional steady model is established to investigate the gas-solid heat transfer in a sinter vertical tank based on the porous media theory and the local thermal non-equilibrium model. The influences of the air flow rate, sinter flow rate, and sinter particle diameter on the gas-solid heat transfer process are investigated numerically. In addition, exergy destruction minimization is used as a new principle for heat transfer enhancement. Furthermore, a multi-objective genetic algorithm based on a Back Propagation (BP) neural network is applied to obtain a combination of each parameter for a more comprehensive performance, with the exergy destruction caused by heat transfer and the one caused by fluid flow as the two objectives. The results show that the heat dissipation and power consumption both gradually increase with an increase of the air mass flow rate. Additionally, the increase of the sinter flow rate results in a decrease of the heat dissipation and an increase of the power consumption. In addition, both heat dissipation and power consumption gradually decrease with an increase of the sinter particle diameter. For the given structure of the vertical tank, the optimal operating parameters are 2.99 kg/s, 0.61 kg/s, and 32.8 mm for the air flow rate, sinter flow rate, and sinter diameter, respectively.

Numerical Investigation on the Strategies for Reducing the Cell Temperature Gradient of an Indirect Internal Reforming Tubular SOFC

2004 ◽  
Author(s):  
Takafumi Nishino ◽  
Hiroshi Iwai ◽  
Kenjiro Suzuki
Keyword(s):  
Temperature Gradient ◽  
Distribution Pattern ◽  
Flow Rate ◽  
Air Flow ◽  
Maximum Temperature ◽  
Air Flow Rate ◽  
Internal Reforming ◽  
Average Temperature ◽  
Reforming Catalyst ◽  
Catalyst Distribution

Strategies to reduce the temperature gradient of the cell have been numerically examined by using a comprehensive analytical model of an indirect internal reforming tubular SOFC, the first generation of which was presented at the last conference in 2003 (1st ICFCSET). In particular, how the air flow rate, gas inlet temperature and density distribution of reforming catalyst affect the thermal field in the cell has been examined. Based on the calculated results, it has been confirmed that larger air flow rate reduces the maximum temperature and accordingly the temperature gradient of the cell, while lower inlet temperatures of gases reduce only the average temperature of the cell. For the reforming catalyst distribution, it has been determined that the temperature gradient of the cell can be fairly reduced by adjusting the amount and allocation of the catalyst. In addition, it has been revealed that the distribution pattern of the catalyst has little effect on the average temperature, so that the power generation performance of the cell is not affected by the adjustment of the catalyst distribution pattern substantially.

scholarly journals Heat transfer in the vortex zone of a cyclone-bed chamber of furnace unit with fluidized bed

2019 ◽  
Vol 64 (1) ◽  
pp. 87-97
Author(s):  
E. A. Pitsuha ◽  
E. K. Buchilko ◽  
Yu. S. Teplitskii ◽  
D. S. Slizhuk
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Fluidized Bed ◽  
Flow Rate ◽  
Radial Direction ◽  
Air Flow ◽  
Air Flow Rate ◽  
Outlet Hole ◽  
The Heat Transfer Coefficient

An experimental investigation of the heat-transfer coefficient to a spherical probe in a cyclone-bed chamber with fluidized bed in the “cold” and “hot” regimes has been carried out. The heat-transfer coefficient was determined by the regular thermal regime. The dependences of the heat-transfer coefficient in the vortex-bed furnace on the various parameters: the diameter of the outlet hole, the air flow rate, the share of the bottom blast and the location of the probe were determined. It is revealed that in the “cold” regime the heat-transfer coefficient has practically constant value in the radial direction, it almost does not depend on the diameter of the outlet hole and the share of the bottom blast and depends significantly on the position of the probe along the height of the furnace and the air flow rate. The effect of flow swirling on the heat-transfer coefficient in a cyclone-bed chamber with fluidized bed is determined. When the fuel burns (“hot” regime), the heat-transfer coefficient is not constant in the radial direction and accept the maximum values in the central area of the chamber. At the same time, the part of conductive-convective component in the total heat-transfer coefficient to the spherical probe, depending on its radial position, is estimated at 40–70 %. The results can be used in the design and creation of modern high-efficiency furnaces for burning local solid biofuels.

Sign in / Sign up

Export Citation Format

Share Document