scholarly journals Effect of Differential Mass Flow Rate on the Thermal Performance of Double Duct Packed Bed Solar Air Heaters

2012 ◽  
pp. 1300-1304 ◽  
Author(s):  
Prashant Kumar
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Thermal Performance ◽  
Packed Bed

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

2018 ◽  
Vol 22 (1 Part B) ◽  
pp. 487-494 ◽  
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.

Thermal Performance Analysis and Optimization of Solar Assisted Heat Pump Water Heater

2014 ◽  
Vol 592-594 ◽  
pp. 2416-2421
Author(s):  
R.N. Kokila ◽  
S. Rajakumar
Keyword(s):  
Mass Flow Rate ◽  
Heat Pump ◽  
Mass Flow ◽  
Flow Rate ◽  
Thermal Performance ◽  
Optimization Technique ◽  
Direct Expansion ◽  
Water Heater ◽  
Rate Optimization ◽  
Flat Plate Collector

The main objective of this paper is to analyze the thermal performance of direct expansion solar assisted heat pump DX-SAHP(A) by numerical simulation in MATLAB and comparing it with the thermal performance of DX-SAHP(B) which has an optimized collector area and mass flow rate. Optimization is performed for high exergy efficiency using Particle Swarm Optimization (PSO) and Artificial Bee Colony (ABC) optimization technique. The flat plate collector of solar water heater is used as the evaporator with refrigerant (R22).With the optimized value of mass flow rate as 0.055 kg/sec, width as 0.03 m and diameter of riser tubes as 0.021 m the performance of the optimized system has a maximum COP of 6.85 which is greater than the COP of DX-SAHP(A) and the final water temperature of is obtained 100 minutes earlier in the optimized system i.e. DX-SAHP(B) with compressor work less than the system A

Applying CFD for Studying the Dynamic and Thermal Behavior of Solar Chimney Drying System with Reversed Absorber

2017 ◽  
Vol 13 (11) ◽  
Author(s):  
Souheyla Khaldi ◽  
A. Nabil Korti ◽  
Said Abboudi
Keyword(s):  
Thermal Behavior ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Numerical Study ◽  
Packed Bed ◽  
Maximum Temperature ◽  
Storage Material ◽  
Solar Chimney ◽  
Solar Dryer

AbstractThis article provides numerical study of the solar chimney (SC) assembled with a reversed absorber and packed bed for the indirect-mode solar dryer. The present study was designed to determine the effects of using the SC in three configuration and physical proprieties of the packed (thickness and porosity) on the dynamic and thermal behavior of airflow. The results reveal that (1) using SC without storage material can increase the maximum mass flow rate up to 5%. However, integrating a storage material in the SC can improve the mass flow rate up to 32% during nighttime; (2) the use of a packed bed can decrease the crops temperature fluctuation until about 76% and increase the operating time of the solar dryer up to 12.5 hours rather than 10 hours in the case without packed bed; (3) increasing the porosity from 0.1 to 0.8 can increase the maximum temperature by about 10°C.

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.

Fan-Shaped Hole Effects on the Aero-Thermal Performance of a Film-Cooled Endwall

2005 ◽  
Vol 128 (1) ◽  
pp. 43-52 ◽  
Author(s):  
Giovanna Barigozzi ◽  
Giuseppe Benzoni ◽  
Giuseppe Franchini ◽  
Antonio Perdichizzi
Keyword(s):  
Secondary Flow ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Thermal Performance ◽  
Film Cooling ◽  
Shaped Hole ◽  
Adiabatic Effectiveness ◽  
Endwall Cooling ◽  
Injection Rates

The present paper investigates the effects of a fan-shaped hole endwall cooling geometry on the aero-thermal performance of a nozzle vane cascade. Two endwall cooling geometries with four rows of holes were tested, for different mass flow rate ratios: the first configuration is made of cylindrical holes, whereas the second one features conical expanded exits and a reduced number of holes. The experimental analysis is mainly focused on the variations of secondary flow phenomena related to different injection rates, as they have a strong relationship with the film cooling effectiveness. Secondary flow assessment was performed through downstream 3D aerodynamic measurements, by means of a miniaturized 5-hole probe. The results show that at high injection rates, the passage vortex and the 3D effects tend to become weaker, leading to a strong reduction of the endwall cross flow and to a more uniform flow in spanwise direction. This is of course obtained at the expense of a significant increase of losses. The thermal behavior was then investigated through the analysis of adiabatic effectiveness distributions on the two endwall configurations. The wide-banded thermochromic liquid crystals (TLC) technique was used to determine the adiabatic wall temperature. Using the measured distributions of film-cooling adiabatic effectiveness, the interaction between the secondary flow vortices and the cooling jets can be followed in good detail all over the endwall surface. Fan-shaped holes have been shown to perform better than cylindrical ones: at low injection rates, the cooling performance is increased only in the front part of the vane passage. A larger improvement of cooling coverage all over the endwall is attained with a larger mass flow rate, about 1.5% of core flow, without a substantial increase of the aerodynamic losses.

scholarly journals Thermal performance measurement of additive manufactured high-temperature compact heat exchangers

2021 ◽  
Vol 2116 (1) ◽  
pp. 012095
Author(s):  
M. Fuchs ◽  
D. Heinrich ◽  
X. Luo ◽  
S. Kabelac
Keyword(s):  
High Temperature ◽  
Heat Exchanger ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Thermal Performance ◽  
Heat Exchangers ◽  
Fluid Temperature ◽  
Test Rig ◽  
Temperature Heat

Abstract Due to increased distribution of high-temperature processes in energy and process plants, more efficient and compact high-temperature heat exchangers are being developed. The additive manufacturing allows the construction of compact sizes and application-specific requirements. To evaluate the thermal performance of these heat exchangers, experimental investigations are evident. This study presents a test rig for testing compact high-temperature heat exchangers as well as a first set of thermal performance data of an additively manufactured plate-fin heat exchanger. The test rig can provide a maximum fluid temperature of 900°C and a maximum mass flow rate of 0.8 kg/min. A steam unit can add steam to the fluid stream to evaluate the influence of gas radiation on the thermal performance. The capabilities of this test rig are being tested with the plate-fin heat exchanger, varying the mass flow rate between 0.2 - 0.52 kg/min at a hot and cold inlet temperature of 750°C and 250°C. The overall effectiveness of the heat exchanger is approx. 0.9.

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