The hybrid (PVT) double-pass system with a mixed-mode solar dryer for drying banana

In this paper, the hybrid PVT double pass system with a mixed-mode solar dryer type under forced convection has been designed, fabricated and installed for drying crops. The dryer was tried by drying 300 grams of banana slices in the air temperature of dryer range from 43.2 to 60.2°C. The initial moisture rate of banana was about 78% and the most dropped in moisture content was from 78% to 33% after 8 hours of the drying process. The banana slices are distributed in two identical trays and it was noticed that the most and least decreasing in weight of banana samples was from 150 to 48 gram and from 150 to 55 gram in lower and upper tray respectively, when the mass flow rate as 0.031 and 0.017 kg/s, which means that the high reduction was 68% of weight banana at a high mass flow rate of airflow. The critical parameter such as temperature distribution of the PVT with dryer room, useful heat gain, and thermal efficiency are computed by using the MATLAB 2015b program built for this purpose. The optimum useful heat gain and thermal efficiency were reached 423.7 and 52.98% respectively when the solar radiation 1190 and the mass flow rate of 0.031 kg/s.

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Energy-based performance analysis of a double pass solar air collector integrated to triangular shaped fins

International Journal of Energy and Environmental Engineering ◽

10.1007/s40095-021-00422-z ◽

2021 ◽

Author(s):

Maytham H. Machi ◽

Maytham A. Al-Neama ◽

J. Buzás ◽

I. Farkas

Keyword(s):

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Thermal Efficiency ◽

Outlet Temperature ◽

Double Pass ◽

Solar Air Collector ◽

Collector Efficiency ◽

Useful Heat ◽

Air Channels

AbstractIn this paper, the performance of a double pass solar air collector with triangular integrated fins was investigated experimentally at Hungarian University of Agriculture and Life Sciences in Gödöllő, Hungary. The focus of this research is on energy-based performance evaluation. The thermal efficiency of the collector has been compared by testing two collectors that had the same design, with and without fins. The effect of the collector's air mass flow rate on thermal performance was investigated under various environmental situations. The results revealed that the temperature difference is always higher through the finned collector and the higher variation temperature between the inlet and outlet temperature leads to higher useful heat. The daily thermal efficiency of the finned collector was 56.57%, 59.41%, and 61.42%, while for the un-finned collector was 51.04%, 53.28%, and 57.08% for the mass flow rate 0.0081, 0.0101, and 0.0121 kg/s. The finned double pass solar air collector improved the thermal efficiency by 4.3–6.1% over the un-finned one. The efficiency of the finned collector is always higher than the un-finned one regardless of the mass flow rate. The presence of the fins to the top air channels significantly increases collector efficiency, owing to the increased absorbing surface area, which is responsible for increasing the internal thermal convective exchanges. Moreover, it creates a turbulence airflow, meaning that the air will be in good contact with the absorber plate and penetrate all regions, reducing the dead zones contributing to increased heat transfer.

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Efficiency Enhancement in Double-Pass Perforated Glazed Solar Air Heaters with Porous Beds: Taguchi-Artificial Neural Network Optimization and Cost–Benefit Analysis

Sustainability ◽

10.3390/su132111654 ◽

2021 ◽

Vol 13 (21) ◽

pp. 11654

Author(s):

Roozbeh Vaziri ◽

Akeem Adeyemi Oladipo ◽

Mohsen Sharifpur ◽

Rani Taher ◽

Mohammad Hossein Ahmadi ◽

...

Keyword(s):

Neural Network ◽

Artificial Neural Network ◽

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Thermal Efficiency ◽

Exergy Efficiency ◽

Wire Mesh ◽

Double Pass ◽

Artificial Neural

Analyzing the combination of involving parameters impacting the efficiency of solar air heaters is an attractive research areas. In this study, cost-effective double-pass perforated glazed solar air heaters (SAHs) packed with wire mesh layers (DPGSAHM), and iron wools (DPGSAHI) were fabricated, tested and experimentally enhanced under different operating conditions. Forty-eight iron pieces of wool and fifteen steel wire mesh layers were located between the external plexiglass and internal glass, which is utilized as an absorber plate. The experimental outcomes show that the thermal efficiency enhances as the air mass flow rate increases for the range of 0.014–0.033 kg/s. The highest thermal efficiency gained by utilizing the hybrid optimized DPGSAHM and DPGSAHI was 94 and 97%, respectively. The exergy efficiency and temperature difference (∆T) indicated an inverse relationship with mass flow rate. When the DPGSAHM and DPGSAHI were optimized by the hybrid procedure and employing the Taguchi-artificial neural network, enhancements in the thermal efficiency by 1.25% and in exergy efficiency by 2.4% were delivered. The results show the average cost per kW (USD 0.028) of useful heat gained by the DPGSAHM and DPGSAHI to be relatively higher than some double-pass SAHs reported in the literature.

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

Thermal Science ◽

10.2298/tsci131015085s ◽

2016 ◽

Vol 20 (1) ◽

pp. 175-183 ◽

Cited By ~ 1

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.

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Off-Design Dynamic Performance Analysis of a Solar Aided Coal-Fired Power Plant

Energies ◽

10.3390/en14102950 ◽

2021 ◽

Vol 14 (10) ◽

pp. 2950

Author(s):

Vinod Kumar ◽

Liqiang Duan

Keyword(s):

Power Plant ◽

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Thermal Efficiency ◽

Dynamic Performance ◽

Feed Water ◽

Saving Rate ◽

Coal Consumption ◽

Dynamic Performance Analysis

Coal consumption and CO2 emissions are the major concerns of the 21st century. Solar aided (coal-fired) power generation (SAPG) is paid more and more attention globally, due to the lesser coal rate and initial cost than the original coal-fired power plant and CSP technology respectively. In this paper, the off-design dynamic performance simulation model of a solar aided coal-fired power plant is established. A 330 MW subcritical coal-fired power plant is taken as a case study. On a typical day, three various collector area solar fields are integrated into the coal-fired power plant. By introducing the solar heat, the variations of system performances are analyzed at design load, 75% load, and 50% load. Analyzed parameters with the change of DNI include the thermal oil mass flow rate, the mass flow rate of feed water heated by the solar energy, steam extraction mass flow rate, coal consumption, and the plant thermal efficiency. The research results show that, as DNI increases over a day, the coal saving rate will also increase, the maximum coal saving rate reaches up to 5%, and plant thermal efficiency reaches 40%. It is analyzed that the SAPG system gives the best performance at a lower load and a large aperture area.

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An experimental study of the thermal performance of the square and rhombic solar collectors

Thermal Science ◽

10.2298/tsci151228252n ◽

2018 ◽

Vol 22 (1 Part B) ◽

pp. 487-494 ◽

Cited By ~ 1

Author(s):

Aminreza Noghrehabadi ◽

Ebrahim Hajidavaloo ◽

Mojtaba Moravej ◽

Ali Esmailinasab

Keyword(s):

Experimental Study ◽

Flat Plate ◽

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Thermal Performance ◽

Thermal Efficiency ◽

Solar Collectors ◽

Heating Systems ◽

Solar Water Heating

Solar collectors are the key part of solar water heating systems. The most widely produced solar collectors are flat plate solar collectors. In the present study, two types of flat plate collectors, namely square and rhombic collectors are experi?mentally tested and compared and the thermal performance of both collectors is investigated. The results show both collectors have the same performance around noon (?61%), but the rhombic collector has better performance in the morning and afternoon. The values for rhombic and square collectors are approximately 56.2% and 53.5% in the morning and 56.1% and 54% in the afternoon, respectively. The effect of flow rate is also studied. The thermal efficiency of rhombic and square flat plate collectors increases in proportion to the flow rate. The results indicated the rhombic collector had better performance in comparison with the square collector with respect to the mass-flow rate.

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On-Sun Performance Evaluation of Alternative High-Temperature Falling Particle Receiver Designs

Journal of Solar Energy Engineering ◽

10.1115/1.4041100 ◽

2018 ◽

Vol 141 (1) ◽

Cited By ~ 4

Author(s):

Clifford K. Ho ◽

Joshua M. Christian ◽

Julius E. Yellowhair ◽

Kenneth Armijo ◽

William J. Kolb ◽

...

Keyword(s):

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Thermal Efficiency ◽

Particle Temperature ◽

Free Fall ◽

Mass Flow Rates ◽

Mesh Structures ◽

Free Falling ◽

The Impact

This paper evaluates the on-sun performance of a 1 MW falling particle receiver. Two particle receiver designs were investigated: obstructed flow particle receiver versus free-falling particle receiver. The intent of the tests was to investigate the impact of particle mass flow rate, irradiance, and particle temperature on the particle temperature rise and thermal efficiency of the receiver for each design. Results indicate that the obstructed flow design increased the residence time of the particles in the concentrated flux, thereby increasing the particle temperature and thermal efficiency for a given mass flow rate. The obstructions, a staggered array of chevron-shaped mesh structures, also provided more stability to the falling particles, which were prone to instabilities caused by convective currents in the free-fall design. Challenges encountered during the tests included nonuniform mass flow rates, wind impacts, and oxidation/deterioration of the mesh structures. Alternative materials, designs, and methods are presented to overcome these challenges.

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Numerical and Experimental Study of Microchannel Performance on Flow Maldistribution

Micromachines ◽

10.3390/mi11030323 ◽

2020 ◽

Vol 11 (3) ◽

pp. 323 ◽

Cited By ~ 1

Author(s):

Jojomon Joseph ◽

Danish Rehman ◽

Michel Delanaye ◽

Gian Luca Morini ◽

Rabia Nacereddine ◽

...

Keyword(s):

Reynolds Number ◽

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Thermal Efficiency ◽

Experimental Studies ◽

Wire Mesh ◽

Pressure Losses ◽

Macro Scale ◽

Flow Maldistribution

Miniaturized heat exchangers are well known for their superior heat transfer capabilities in comparison to macro-scale devices. While in standard microchannel systems the improved performance is provided by miniaturized distances and very small hydraulic diameters, another approach can also be followed, namely, the generation of local turbulences. Localized turbulence enhances the heat exchanger performance in any channel or tube, but also includes an increased pressure loss. Shifting the critical Reynolds number to a lower value by introducing perturbators controls pressure losses and improves thermal efficiency to a considerable extent. The objective of this paper is to investigate in detail collector performance based on reduced-order modelling and validate the numerical model based on experimental observations of flow maldistribution and pressure losses. Two different types of perturbators, Wire-net and S-shape, were analyzed. For the former, a metallic wire mesh was inserted in the flow passages (hot and cold gas flow) to ensure stiffness and enhance microchannel efficiency. The wire-net perturbators were replaced using an S-shaped perturbator model for a comparative study in the second case mentioned above. An optimum mass flow rate could be found when the thermal efficiency reaches a maximum. Investigation of collectors with different microchannel configurations (s-shaped, wire-net and plane channels) showed that mass flow rate deviation decreases with an increase in microchannel resistance. The recirculation zones in the cylindrical collectors also changed the maldistribution pattern. From experiments, it could be observed that microchannels with S-shaped perturbators shifted the onset of turbulent transition to lower Reynolds number values. Experimental studies on pressure losses showed that the pressure losses obtained from numerical studies were in good agreement with the experiments (<4%).

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Influence of Steam Injection on Thermal Efficiency and Operating Temperature of GE-F5 Gas Turbines Applying VODOLEY System

Advanced Energy Systems ◽

10.1115/imece2005-79316 ◽

2005 ◽

Cited By ~ 1

Author(s):

Mohsen Ghazikhani ◽

Nima Manshoori ◽

Davood Tafazoli

Keyword(s):

Power Plant ◽

Ambient Temperature ◽

Gas Turbine ◽

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Thermal Efficiency ◽

Gas Turbines ◽

Steam Injection ◽

Gas Turbine Cycle

An industrial gas turbine has the characteristic that turbine output decreases on hot summer days when electricity demand peaks. For GE-F5 gas turbines of Mashad Power Plant when ambient temperature increases 1° C, compressor outlet temperature increases 1.13° C and turbine exhaust temperature increases 2.5° C. Also air mass flow rate decreases about 0.6 kg/sec when ambient temperature increases 1° C, so it is revealed that variations are more due to decreasing in the efficiency of compressor and less due to reduction in mass flow rate of air as ambient temperature increases in constant power output. The cycle efficiency of these GE-F5 gas turbines reduces 3 percent with increasing 50° C of ambient temperature, also the fuel consumption increases as ambient temperature increases for constant turbine work. These are also because of reducing in the compressor efficiency in high temperature ambient. Steam injection in gas turbines is a way to prevent a loss in performance of gas turbines caused by high ambient temperature and has been used for many years. VODOLEY system is a steam injection system, which is known as a self-sufficient one in steam production. The amount of water vapor in combustion products will become regenerated in a contact condenser and after passing through a heat recovery boiler is injected in the transition piece after combustion chamber. In this paper the influence of steam injection in Mashad Power Plant GE-F5 gas turbine parameters, applying VODOLEY system, is being observed. Results show that in this turbine, the turbine inlet temperature (T3) decreases in a range of 5 percent to 11 percent depending on ambient temperature, so the operating parameters in a gas turbine cycle equipped with VODOLEY system in 40° C of ambient temperature is the same as simple gas turbine cycle in 10° C of ambient temperature. Results show that the thermal efficiency increases up to 10 percent, but Back-Work ratio increases in a range of 15 percent to 30 percent. Also results show that although VODOLEY system has water treatment cost but by using this system the running cost will reduce up to 27 percent.

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Modeling of Bifacial Photovoltaic-Thermal (PVT) Air Heater with Jet Plate

International Journal of Heat and Technology ◽

10.18280/ijht.390409 ◽

2021 ◽

Vol 39 (4) ◽

pp. 1117-1122

Author(s):

Win Eng Ewe ◽

Ahmad Fudholi ◽

Kamaruzzaman Sopian ◽

Nilofar Asim

Keyword(s):

Mass Flow Rate ◽

Air Temperature ◽

Mass Flow ◽

Flow Rate ◽

Thermal Efficiency ◽

Solar Irradiation ◽

Electrical Efficiency ◽

Air Heater ◽

Packing Factor ◽

Pv Panel

This research demonstrates how to develop a novel energy balance equation to investigate heat transmission between the components of a bifacial photovoltaic-thermal (PVT) air heater with a jet plate. The temperature output and efficiency of the system are shown. A greater mass flow rate reduces the exit air temperature and increases the thermal efficiency of the thermal component. Increased sun irradiation raises the output air temperature and thermal efficiency. In terms of electrical efficiency, a greater mass flow rate reduces the temperature of the PV panel while increasing electrical efficiency. On the other hand, higher solar irradiation raises the temperature of the PV panel, lowering its electrical efficiency. The maximum thermal efficiency of BPVTJPR is 51.09% under the circumstances of 12 PV cells with a packing factor of 0.66, a jet plate reflector with 36 holes, 900 W/m2 solar irradiances, and a mass flow rate of 0.035 kg/s. The maximum electrical efficiency of BPVTJPR is 10.73% under the circumstances of 12 PV cells with a packing factor of 0.66, a jet plate reflector with 36 holes, 700 W/m2 solar irradiances, and a mass flow rate of 0.035 kg/s.

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