Numerical analysis on thermal energy storage device to improve the drying time of indirect type solar dryer

2018 ◽  
Vol 54 (12) ◽  
pp. 3631-3646 ◽  
Author(s):  
Satyapal Yadav ◽  
Abhay Bhanudas Lingayat ◽  
V.P. Chandramohan ◽  
V. R. K. Raju
2018 ◽  
Vol 140 (3) ◽  
Author(s):  
Satyapal Yadav ◽  
V. P. Chandramohan

Solar dryer with thermal energy storage device is an essential topic for food drying applications in industries. In this work, a two-dimensional (2D) numerical model is developed for the application of solar drying of agricultural products in an indirect type solar dryer. The phase-change material (PCM) used in this work is paraffin wax. The study has been performed on a single set of concentric tube which consists of a finned inner copper tube for air flow and an outer plastic tube for PCM material. The practical domain is modeled using ANSYS, and computer simulations were performed using ANSYS fluent 2015. The air velocity and temperature chosen for this study are based on the observation of indirect type solar dryer experimental setup. From this numerical analysis, the temperature distribution, melting, and solidification fraction of PCM are estimated at different air flow velocities, time, and inlet temperature of air. It is concluded that the drying operation can be performed up to 10.00 p.m. as the PCM transfers heat to inlet air up to 10.00 p.m. and before it got charged up to 3.00 p.m. because of solar radiation. The maximum outlet temperature is 341.62 K (68.62 °C) which is suitable for food drying applications. Higher air flow velocity enhances quick melting of PCM during charging time and quick cooling during recharging of inlet air; therefore, higher air flow velocity is not preferred for food drying during cooling of PCM.


2017 ◽  
Vol 39 (3) ◽  
pp. 268-276 ◽  
Author(s):  
Nima Bonyadi ◽  
Süleyman Kazım Sömek ◽  
Cemil Cihan Özalevli ◽  
Derek Baker ◽  
İlker Tarı

Author(s):  
Bhumika Mohod ◽  
Devilal Verma ◽  
Aditya Nimje ◽  
Aniket Mishra ◽  
Anurudha Brahmne ◽  
...  

In the solar dryer is a device in which drying the substance with the help of only solar energy. In this system we observe that the time take to perform the operation high and the effectiveness is very low, and availability also low. With the help of thermal energy storage device, we update the solar dryer. In solar dryer with thermal energy storage device. The energy used is solar as well as thermal energy, availability is increase and effectiveness is also increase. When the blower switch is on the atmospheric air is drawn in the copper tube, surrounding of the copper tube is hot water is available. Hence the hot water is available the atmospheric air is exchange the heat the air get hot this hot air is hot water is move to container (vessel). Then the temperature of the container (vessel) increase. Hence the time take for the perform operation is decrease.


Author(s):  
Zachary M. Theroff ◽  
Dre Helmns ◽  
Van P. Carey

Previous efforts to model the effectiveness of heat input and extraction from a thermal storage unit have generally been based on the definition of a constant conductance of heat from the working fluid to the phase change storage material. In order to capture the effects of changing thermal resistance between the working fluid and melt front location, this paper presents a method using a resistor network analogy to account for thermal conductance as a function of melt fraction. This expression for thermal conductance is then implemented in an existing numerical framework. Results are validated by comparing calculations for a single unit cell using a quasi-steady Stefan problem approach, a finite difference scheme, and more general form solutions from literature. The variable approach is then compared with an average value for overall thermal conductivity, U, to characterize the performance of a thermal energy storage unit consisting of a series of these unit cells. Overall effectiveness in the thermal energy storage device is found to be within 0.6% agreement when comparing these methods, though local percent deviation can be as high as 113%. Depending on the needed accuracy and use case for such a numerical framework, suggestions are provided on whether an average value for U is sufficient for characterizing such a thermal energy storage device. Discussion is also provided on the flexibility of the computation schemes described by testing the sensitivity of the results via changes in dimension-less input parameters.


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