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In this study, a phase change material (PCM)‐encapsulated packed‐bed thermal energy storage (PB‐TES) system is intended for Day‐round space heating in the winter. Solar concentric collectors act for day‐time heating and TES charging, while the stored energy can be used at night and intermediate time for space heating. A region‐wise techno‐economic analysis of PCM candidates is made to compare the costs and sizes of solar collectors and PB‐TES. A spherical capsule filled with sodium nitrite (NaNO2) and sodium nitrate (NaNO3) is numerically investigated during the PCM charging at constant thermal input. After complete liquefication, the charging time for NaNO2 and NaNO3 capsules is 3280 and 4300 s, respectively, holding the maximum stored energy of 733.4 KJ/kg at 285°C and 687.27 kJ/kg at 310.12°C, respectively. In addition, the stored exergy is obtained 238.78 and 234.74 kJ/kg for NaNO2 and NaNO3, respectively; however, the average exergetic effectiveness for NaNO2 and NaNO3 are 0.54 and 0.46. Despite the lower energy storage capacity (kJ/kg) of NaNO3, the PB‐TES volume is less with NaNO3 than with NaNO2 due to higher density. However, the average cost ($/tonne) of NaNO3 PCM is 50% higher than NaNO2. Subsequently, the thermal efficiency of the proposed system is estimated at 27.68% and 26.94% during day and night‐time operations. [ABSTRACT FROM AUTHOR]

A numerical model for simultaneous heat and mass transfer was developed for solar drying of spherical objects and the object considered is green peas. Solar collector outlet temperature is assumed as drying chamber temperature and justified through energy balance equations. Assumptions are imposed on heat and mass transfer governing equations without losing the physics of the problem. Discretization is performed by finite difference method with implicit scheme. To generalize, the governing equation and boundary conditions are non-dimensionalized. The set of finite difference equations was solved by Tridiagonal Matrix Algorithm and a computer code in MATLAB was developed to solve them. The drying curves showed two stages of drying, initial, and secondary drying stage. At all drying temperatures and drying time, the center moisture was maximum and it was minimum at the boundary. A percentage of 85.67 surface moisture content and 25.33% center moisture was eliminated in the first 1 hr at 348 K. The product should be dried up to 7.45, 4.74, and 3.74 hr at air drying temperatures of 318, 333, and 348 K respectively, to maintain 10% of the product's initial moisture content. The result is compared with the experimental result from literature and they are found to be in good agreement. [ABSTRACT FROM AUTHOR]

In the present study, we investigated the effect of pH on phase transition of TiO2nanoparticles synthesized by sol-gel protocol and identification by various techniques as x-ray diffraction, energy dispersive x-ray spectroscopy (EDX), Raman spectroscopy, scanning electron microscopy, etc. Corresponding TiO2phase change from rutile to anatase and mixture of both anatase and rutile phases by tuning the pH of the reaction mixture is clear from x-ray diffraction studies. The presence of (101) and (110) planes corresponded to anatase and rutile phases of TiO2,respectively. [ABSTRACT FROM AUTHOR]

In the present study the hydro alcoholic extract of whole plant of Ageratum houstonianum was investigated for its anti diabetic activity at two dose levels on both alloxan induced diabetic rats and normoglycaemic rats. The blood glucose levels were estimated in both alloxan induced hyperglycaemic and normoglycaemic rats. The acclimatized animals were kept fasting for 24 h with water ad libitum and injected a dose of 120 mg/kg of alloxan monohydrate in normal saline intraperitoneally. Test extract at 200 and 400 mg/kg and glibenclamide at 2.5 mg/kg was administered. Blood glucose level was estimated at 0 h, 1 h, 2 h, 4 h and 8 h respectively. Hydro alcoholic extract of A. houstonianum whole plant was found to produce significant (p<0.01) reduction in blood glucose concentration between 2-4 hours of administration in both alloxan induced hyper glycaemic and normoglycaemic rats at 400 mg/kg dose. When compared with the reference control glibenclamide, the extract caused noticeable reduction in the blood glucose level in both classes of animals which was demonstrated in above methods. Hence, from the above results it can be concluded that, Ageratum houstonianum whole plant extract showing good anti diabetic activity. [ABSTRACT FROM AUTHOR]

Phase change material (PCM) based passive cooling of photovoltaics (PV) can be highly productive due to high latent heat capacity. However, the low rate of heat transfer limits its usefulness. Thus, the presented work aims at the improvement in PV cooling by using finned PCM (FPCM) heat sinks. In the present study, PCM heat sink and FPCM heat sinks were investigated numerically for PV cooling and the extracted heat is used for space heating. 4 kWp PV, PV-PCM and PV-FPCM systems were studied under the weather conditions of Southeast of England. It was observed that the PCM heat sinks can drop the peak PV temperature by 13 K, whereas FPCM heat sinks can enhance the PV cooling by 19 K. The PCM heat sinks can increase the PV electrical efficiency from 13% to 14%. Moreover, the daily electricity generation can be boosted by 7% using PCM and 8% by using FPCM heat sinks. In addition, 7 kWh of thermal output was achieved using the FPCM heat sink, and the overall efficiency of system increased from 13% to 19%. [ABSTRACT FROM AUTHOR]