scholarly journals EXPERIMENTAL INVESTIGATION ON A SOLAR AIR HEATER WITH AND WITHOUT OBSTACLE

2021 ◽  
Vol 9 (2) ◽  
pp. 251-257
Author(s):  
A. R. Vijay Babu, Et. al.
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Software Tool ◽  
Solar Air Heater ◽  
Outlet Temperature ◽  
Temperature Level ◽  
Hot Air ◽  
Air Heating ◽  
Temperature And Pressure ◽  
Annular Fins

 In this paper convection form of heat transfer is used to convert cold air to hot air. Forced convection is preferred for this experimental analysis; obstacles are also used to analyze the temperature level of air with the help of Air Heating Solar Device (AHSD). Semi Annular fins are used as obstacles for this experimental verification. The outlet temperature and pressure drop of SAH were determined by changing the fin densities with the help of software tool FLUENT. The analysis result shows that the outlet temperature is more and pressure drop was less in the case of SAH with obstacles when compared to the SAH without obstacles.  

Tube Banks Heat Transfer Enhancement Using Conical Fins

2010 ◽  
Author(s):  
Ignacio Carvajal-Mariscal ◽  
Florencio Sanchez-Silva ◽  
Georgiy Polupan
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
Pressure Drop ◽  
Finned Tube ◽  
Hot Water ◽  
Experimental Results ◽  
Tube Bank ◽  
Finned Tubes ◽  
Tube Banks ◽  
Annular Fins

In this work the heat transfer and pressure drop experimental results obtained in a two step finned tube bank with conical fins are presented. The tube bank had an equilateral triangle array composed of nine finned tubes with conical fins inclined 45 degrees in respect with the tube axis. The heat exchange external area of a single tube is approximately 0.07 m2. All necessary thermal parameters, inlet/outlet temperatures, mass flows, for the heat balance in the tube bank were determined for different air velocities, Re = 3400–18400, and one constant thermal charge provided by a hot water flow with a temperature of 80 °C. As a result, the correlations for the heat transfer and pressure drop calculation were obtained. The experimental results were compared against the analytical results for a tube bank with annular fins with the same heat exchange area. It was found that the proposed tube bank using finned tubes with conical fins shows an increment of heat transfer up to 58%.

Thermal performance of a packed bed double pass solar air heater with a latent heat storage system: an experimental investigation

2019 ◽  
Vol 17 (2) ◽  
pp. 203-213 ◽  
Author(s):  
Chaitanya Dosapati ◽  
Mohan Jagadeesh Kumar Mandapati
Keyword(s):  
Heat Transfer ◽  
Solar Energy ◽  
Solar Air Heater ◽  
Transfer Coefficients ◽  
Absorber Plate ◽  
Content Type ◽  
Heat Transfer Coefficients ◽  
Hot Air ◽  
Sunshine Hours ◽  
Poultry Farms

Purpose Solar energy applications are limited because of its intermittent and discontinuous availability with respect to time. Hence, solar energy thermal conversion systems need integration with thermal storage units (TSUs) to use solar energy in off sunshine hours. This paper aims to perform thermal analysis of a solar air heater (SAH) integrated with a phase change material (PCM)-based TSU to supply hot air during night period. Design/methodology/approach An experimental setup with TSU as main component was prepared with SAH at its upward side, food chamber at its downward side as subcomponents. In TSU, paraffin wax was used as thermal energy storage material. Mass flow rate of air considered as an input parameter in the experiment. Two different absorber plates, namely, plane and ribbed absorber plates were used for the experimentation. Each day for a fixed mass flow of air, observations were made during charging and discharging of PCM. Findings Nusselt number and convection heat transfer coefficients were analytically calculated by considering flow through TSU as external flow over bank of tubes in a rectangular duct. A temperature drop of around 7-8°C during charging of PCM and temperature rise of around 4-5°C during discharging of PCM was observed from the experimental results. The average practical efficiency of TSU with ribbed absorber plate SAH during charging and discharging of PCM was 22 and 6 per cent, respectively, higher than that of TSU with plane absorber plate SAH. Research limitations/implications There are no limitations for research on SAH integrated with TSU. Different PCM including paraffin wax, Glauber’s salt, salt hydrates and water are used for thermal storage. Only limitation is lower efficiency of SAH integrated with TSU because of lower heat transfer coefficients with air as working medium. If it can improve heat transfer coefficients of air then heat transfer rates with these units will be higher. Practical implications There are no practical limitations for research on SAH integrated with TSU. Sophisticated instrumentation is needed to measure flow rates, temperatures and pressure variations of air. Social implications In poultry farms during night, chicks cannot survive at cold climatic conditions. Hence, hot air should be supplied to poultry farms whenever the atmospheric temperature drops. It is proposed that, in combination with TSUs, heat produced by SAH is stored in day time in the form of either sensible or latent heat and is retrieved to provide hot air in the night times. This will reduce total operating costs in poultry farms. Originality/value Conventionally, people are producing hot air by combusting coal in poultry forms. This cost around Rs. 75,000 per month for a batch of 225 to 250 chicks in a poultry form. Hot air could be produced economically during off sunshine hours from SAH integrated with TSU compared to the conventional method of coal burning. Present experimental investigations conducted to fill the literature gap in this area of research and to design a SAH integrated with TSU to produce hot air for poultry forms.

scholarly journals Experimental and Simulation Study of Micro-Channel Backplane Heat Pipe Air Conditioning System in Data Center

2020 ◽  
Vol 10 (4) ◽  
pp. 1255
Author(s):  
Liping Zeng ◽  
Xing Liu ◽  
Quan Zhang ◽  
Jun Yi ◽  
Xiaohua Li ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Heat Transfer Performance ◽  
Outlet Temperature ◽  
Transfer Performance ◽  
Micro Channel ◽  
Heat Transfer Capacity ◽  
The Heat Transfer Coefficient

This paper mainly studies the heat transfer performance of backplane micro-channel heat pipes by establishing a steady-state numerical model. Compared with the experimental data, the heat transfer characteristics under different structure parameters and operating parameters were studied, and the change of heat transfer coefficient inside the system, the air outlet temperature of the back plate and the influence of different environmental factors on the heat transfer performance of the system were analyzed. The results show that the overall error between simulation results and experimental data is less than 10%. In the range of the optimal filling rate (FR = 64.40%–73.60%), the outlet temperature at the lowest point and the highest point of the evaporation section is 22.46 °C and 19.60 °C, the temperature difference does not exceed 3 °C, and the distribution gradient in vertical height is small and the air outlet temperature is uniform. The heat transfer coefficient between the evaporator and the condenser is larger than the heat transfer coefficient under the conditions of low and high liquid charge rate. It increases gradually along the flow direction, and decreases gradually with the flow rate of the condenser. When the width of the flat tube of the evaporator increases from 20 mm to 28 mm, the internal pressure drop of the evaporator decreases by 45.83% and the heat exchange increases by 18.34%. When the number of evaporator slices increases from 16 to 24, the heat transfer increases first and then decreases, with an overall decrease of 2.86% and an increase of 87.67% in the internal pressure drop of the evaporator. The inclination angle of the corrugation changes from 30° to 60°, and the heat transfer capacity and pressure drop increase. After the inclination angle is greater than 60°, the heat transfer capacity and resistance decrease. The results are of great significance to system optimization design and engineering practical application.

A Novel Gas-Water Heat Exchanger With Minichannels

2008 ◽  
Author(s):  
Yang Chen ◽  
Per Lundqvist ◽  
Bjo¨rn Palm
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Low Pressure ◽  
Shell Side ◽  
Hot Air ◽  
Drop Flow ◽  
Counter Current ◽  
Good Heat ◽  
Current Heat

In the current study, a novel gas water heat exchanger with minichannels is designed, built and tested. The heat exchanger is mainly composed of a number of concentric ring shaped plates, which are made up of several heat exchanger tubes. The ring shaped plates are arranged in parallel and placed in a shell. The heat exchanger is designed as a counter current heat exchanger with laminar flow on the heat exchanger’s shell-side (gas side) and therefore has a very low pressure drop on the shell side. The heat exchanger was tested with water and hot air on its tube-side and shell-side respectively. All the necessary parameters like inlet and outlet temperatures on tube-side and shell-side as well as the pressure drop, flow rate of fluids, etc. were measured. Different existing correlations were used to calculate the overall heat transfer coefficient and the results were compared with the measured value. The measured results show that the new designed heat exchanger can achieve a good heat transfer performance and also maintain a low pressure drop on shell-side (gas side).

scholarly journals Experimental Studies on a Solar Air Heater Having V-Corrugated Absorber Plate with Obstacles Bent Vertically

2014 ◽  
Vol 493 ◽  
pp. 86-92 ◽  
Author(s):  
Ekadewi A. Handoyo ◽  
Djatmiko Ichsani ◽  
Prabowo ◽  
S. Sutardi
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Flat Plate ◽  
Air Temperature ◽  
Temperature Rise ◽  
Experimental Studies ◽  
Bottom Plate ◽  
Solar Air Heater ◽  
Absorber Plate ◽  
Air Heater

A solar air heater (SAH) is a simple heater using solar radiation that is useful for drying or space heating. Unfortunately, heat transfer from the absorber plate to the air inside the solar air heater is low. Some researchers reported that obstacles are able to improve the heat transfer in a flat plate solar air collector and others found that a v-corrugated absorber plate gives better heat transfer than a flat plate. Yet, no work of combining these two findings is found.This paper describes the result of experimental study on a SAH with v-corrugated absorber plate and obstacles bent vertically started from 80oto 0owith interval 10oon its bottom plate. Experiments were conducted indoor at five different Reynolds numbers (1447 Re 7237) and three different radiation intensities (430, 573, and 716 W/m2).It is found that the obstacles improve SAH performance. Both the air temperature rise and efficiency increase with inserting obstacles bent at any angle vertically. Unfortunately, the air pressure drop is increasing, too. Obstacles bent vertically at smaller angle (means more straight) give higher air temperature rise and efficiency. However, the optimum angle is found 30o. The air temperature rise and efficiency will be 5.3% lower when the obstacles bent 30oinstead of 0o, but the pressure drop will be 17.2% lower.

Numerical Investigation of Single Phase Heat Transfer Enhancement in a Microchannel With Grooved Surfaces

2008 ◽  
Author(s):  
Nemat Baghernezhad ◽  
Omid Abouali
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Sink ◽  
Single Phase ◽  
Transfer Problem ◽  
Removal Rate ◽  
Heat Removal ◽  
Transfer Characteristic ◽  
Outlet Temperature ◽  
Noticeable Effect

This paper presents an investigation for two types of the grooves (rectangular and arc shapes) fabricated in the microchannel surfaces which leads to enhancement in single phase cooling. The pressure drop and heat transfer characteristic of the single phase microchannel heat sink were investigated numerically for laminar flow. For this purpose the conjugate heat transfer problem involving simultaneous determination of the temperature field in both solid and liquid regions was solved numerically. The heat sink includes an array of rectangular microchannels with grooved surface structures in the side walls and floor of the channel. The effect of these grooves on the pressure drop, outlet temperature of cooling fluid and the heat transfer rate were analyzed. The result showed that using a microchannel with grooved surfaces has a noticeable effect and heat removal rate can be increased using this technique. Also the grooves with the arc shapes have a better performance compared with a rectangular shape groove.

scholarly journals Optimizing Design and Analysis on The Helically Coiled Tube Heat Exchanger By Providing Fins

2020 ◽  
Vol 6 (1) ◽  
pp. 8
Author(s):  
Sunil Kumar ◽  
Ravindra Mohan
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Total Pressure ◽  
Outlet Temperature ◽  
Tube Heat Exchanger ◽  
Helically Coiled Tube ◽  
Total Pressure Drop ◽  
Optimizing Design ◽  
Coil Heat Exchanger

Heat exchangers are an essential part in an assortment of mechanical settings, for example, cooling frameworks, force plants, refineries, and in this way ceaseless endeavor are made to expand their heat transfer efficiencies. Optimize design of helical coil heat exchanger by using fins and the Compare pressure & temperature by conventional design. The final outcome of the study increase the total heat transfer rate inside the domain. And increase the pressure drop inside the domain. The water outlet temperature decrease up to 315k and cold outlet temperature increase up to 320 k. and total pressure drop increase with the temperature increases. Finally the CFD data were compared with previous data  the total pressure drop increase up to 0.65 bar for case-2.the overall efficiency of the system incites up to 5%  to 6%.

scholarly journals Design of Hybrid Industrial Solar Drying Unit

2019 ◽  
Vol 4 (1) ◽  
pp. 24-31
Author(s):  
Haider A. Gadir Elbasher ◽  
Babiker Karama Abdalla ◽  
Adil Ali Mohamed
Keyword(s):  
Static Condition ◽  
Ambient Air ◽  
Solar Air Heater ◽  
Outlet Temperature ◽  
Absorber Plate ◽  
Is Success ◽  
Set Point ◽  
Pilot Unit ◽  
Air Heater ◽  
Hot Air

This study done for designing  industrial solar air heater drying unit with tow part of experimental steps(selecting solar air hater  type and other par for controlling outlet temperature through mixing hot and ambient air through static mixture) ., The experiment done for 6 six days for each type using fabricated glass covered corrugated solar air heater with tow possibility of modifications  one of them with fixed absorber plate defined as type one and other one tested with removed absorber  plate which defined as type two  experiments done with full  accessory (air supply fans, temperature mea with same test study using device, fresh air motor controlling RPM and fabricated static mixture. The drying temperature range (45 C to 55 C).Before testing pilot unit calculation of predicted hot air temperature was done for validity of unit then the experiments has been made with pilot unit of solar air heater with fresh air steam and static condition, the result show that solar air heater type one is better for stable results for out let temperature and suitable for working. also the experiments show that, the presented value of temperature of hot mixed air of SAH type one have fitness with set point of controller 90% for day one and day two but for SAH type two the present value haven’t fitness with set point, the reading either high or low than the set temperature   , for the other part of study prove that mixing hot air from solar air heater and fresh ambient air is success and control system working properly for the propellant drying process.

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