scholarly journals Experimental Study of Thermal Performance of One-Ended Evacuated Tubes for Producing Hot Air

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Ashish Kumar ◽  
Sanjeev Kumar ◽  
Utkarsh Nagar ◽  
Avadhesh Yadav
Keyword(s):  
Thermal Performance ◽  
Temperature Difference ◽  
Air Flow ◽  
Climatic Conditions ◽  
Working Fluid ◽  
Outlet Temperature ◽  
Flow Rates ◽  
Solar Air Collector ◽  
Evacuated Tubes ◽  
Evacuated Tube

The thermal performance of an evacuated tube solar air collector is experimentally investigated at different air flow rates. Air is used as a working fluid in experimental setup and tested in Indian climatic conditions. The evacuated tube solar air collector consists of fifteen evacuated tubes and manifold channel. The manifold channel consists of a hollow pipe (square pipe) in centre through which air flows. The temperature difference and efficiency are studied with different air flow rates. The reflectors are used to enhance the performance of evacuated tubes solar air collector. It is observed that in case of reflector evacuated tube solar air collector gives higher outlet temperature and temperature difference and has better thermal performance as compared to the case without reflector. The maximum outlet temperature and temperature difference of air are found to be 97.4°C and 74.4°C at a flow rate of 6.70 kg/hr.

Thermal analysis on charging and discharging behaviour of a phase change material-based evacuated tube solar air collector

2016 ◽  
Vol 27 (2) ◽  
pp. 156-172 ◽  
Author(s):  
Neeraj Mehla ◽  
Avadhesh Yadav
Keyword(s):  
Phase Change ◽  
Total Energy ◽  
Phase Change Material ◽  
Flow Rate ◽  
Air Flow ◽  
Air Flow Rate ◽  
Flow Rates ◽  
Solar Air Collector ◽  
Evacuated Tube ◽  
Change Material

The performance analysis on the phase change material-based evacuated tube solar air collector was examined under consecutive and simultaneous charging and discharging modes. Acetamide was used as phase change material. The system performance was evaluated on the basis of the phase change material storage system energy efficiency, exergy efficiency, collector efficiency, the instantaneous energy stored in the phase change material and total energy stored by the system at low and high air flow rates of 0.018 kg/s and 0.035 kg/s, respectively. The maximum average efficiency (17.9%) of the collector was obtained at a high air flow rate during simultaneously charging and discharging of the phase change material. The results obtained demonstrate that the system is more effective when it is operated with high air flow rate during simultaneously charging and discharging of the phase change material. The average total energy at high air flow rates is 1.01 to 1.02 times more in comparison to that at low air flow rates. The findings show the feasibility of the phase change material-based evacuated tube solar air collector for producing hot air for space heating during consecutive and simultaneous charging and discharging of the phase change material in northen Indian climatic conditions. This system would be relevant in areas with good sunlight.

scholarly journals Thermal Performance Improvement of Solar Parabolic Dish System Using Modified Spiral Coil Tubular Receiver

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Rajkumar Malviya ◽  
Prashant V. Baredar ◽  
Anil Kumar
Keyword(s):  
Thermal Performance ◽  
Maximum Efficiency ◽  
Working Fluid ◽  
Outlet Temperature ◽  
Anodized Aluminum ◽  
Innovative Design ◽  
Spiral Coil ◽  
Parabolic Dish ◽  
Turbulence Effect ◽  
Solar Thermal Applications

The present research intends to design an efficient receiver for solar thermal applications with a solar dish concentrator system. Thermal and dynamic analysis is carried out for different convolutions of a spiral coil, and experiments are performed for testing the modified absorber. Experimental results are validated for the spiral absorber with numerical results. Three receivers of different numbers of convolutions are analyzed, and simulation steps are performed for these receivers to make improvements in the system efficiency. Finally, 5 convolutions of a spiral coil tubular absorber are taken for the modified design of the system. Absorber position for every spiral convolution is kept at the focus of the concentrated solar dish collector to achieve maximum efficiency. Material used for the reflective surface is anodized aluminum and copper for the absorber. The diameter of the aperture for the parabolic dish collector is 1.4 m. The maximum absorber temperature for May month comes out to be 296°C, and the maximum working fluid outlet temperature is found to be 294.2°C which is near to simulating temperature of 289.59°C and 288.15°C, respectively. This innovative design of the absorber consists of a feature of a 5 mm extension to the spiral tube at the exit and entry; hence, the turbulence effect could be overcome. Experimental thermal efficiency was found the highest (i.e., η th max = 75.98 % ) for May. This work emphasizes on improving thermal performance by obtaining optimum absorber size using convolution strategy. Investigation of 5 convolutions of spiral coil tubular absorber with extended ends for obtaining optimum performance than existing work is the superiority of this work.

Theoretical Study on Thermal Performance of Trombe Wall Combined with Solar Air Collector

2012 ◽  
Vol 512-515 ◽  
pp. 208-213
Author(s):  
Yu Bie ◽  
Fang Zhou ◽  
Ming Fu Hu ◽  
Qian Peng ◽  
Wen Yuan Mao ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Thermal Performance ◽  
Air Flow ◽  
Flow Channel ◽  
C Programming ◽  
Solar Air Collector ◽  
Trombe Wall ◽  
Collecting Efficiency ◽  
Solar Wall ◽  
The Mathematical Model

A thermal performance mathematical model of Trombe wall combined with solar air collector was established on the base of thermodynamics and fluid dynamics analysis. Then we solved the mathematical model by means of calculating program based on C programming language. The calculating results show the influence law of the area ratio of air opening to air flow channel (Ao/Af ) and the thickness of air flow channel affected on the heat collecting efficiency of solar wall. With the increasing of Ao/Af , the efficiency increases firstly, then increases more slowly, and finally comes to steady. The thickness also affects the efficiency in the same way. Though the results still need a further validation by experiments, they are initially proved correct by the qualitative analysis. The theoretical model can be a tool for the structural optimization of the Trombe wall combined with solar air collector.

scholarly journals Performance Investigation of Flat Plate and Evacuated Tube Collectors under Jordan Climate Conditions Using TRNSYS Software

2021 ◽  
Vol 8 (1) ◽  
pp. 142-148
Author(s):  
Mohammed Al-Odat ◽  
Khalida Rawashedsh ◽  
Mohammed Al-Hasan
Keyword(s):  
Flat Plate ◽  
Thermal Performance ◽  
Energy Gain ◽  
Cold Climate ◽  
Hot Water ◽  
Inlet Temperature ◽  
Outlet Temperature ◽  
Climate Conditions ◽  
Hot Climate ◽  
Evacuated Tube

The performance of the Flat Plate Collector (FPC) and Evacuated Tube Collector (ETC) for domestic hot water applications under Jordan climate conditions was theoretically investigated using TRNSYS software. The presented simulation model can provide a long-term evaluation of system performance at different weather conditions. This simulation was carried out during 24 hours in 21 June, is considered as a hot climate and 21 January is considered as a cold climate; under the meteorological conditions of both Irbid and Aqaba cities in Jordan. The inlet water temperature of the first collector, collector area, water flow rate and tilt angle were considered 15℃, 2.04 m2, 0.0139 kg/s and 45 degrees respectively. The outlet temperature of each collector was considered as the inlet of the previous collector. Three collectors in series were applied to increase the output temperature up to 90-100℃. The results showed that TE increased with the decrease in the inlet temperature, which means the useful energy gain (Qu) of the first collector is greater than the 2nd and the 3rdcollector. The useful energy gain (Qu) of ETC is greater than of FPC, and the useful energy gain (Qu) of cold climate is less than hot climate. The output temperature of ETCs is greater than that of FPCs for Irbid city in cold and hot climate. Furthermore, for Aqaba in cold climate and in hot climate the outlet temperature of ETCs is higher than FPCs. Additionally, the daily thermal performance of the ETCs is significantly better than the FPCs in cold climate. Meanwhile, thermal performance of both collectors are close in a hot climate.

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