Herein, the synthesis, characterization and thermal behaviour of imidazole-based two copper-phosphate mixtures, A = Cu 2 (PO 4 )(OH)ÁCu(HPO 4 )(H 2 O)Á(C 3 H 4 N 2 ) 2 . 3.25 H 2 O and B = Cu 3 (PO 4 ) 2 H 2 OÁ(C 3 H 4 N 2 ) 3 (H 2 O)Á0.1(C 3 H 4 N 2 ).3.25 H 2 O are reported. The characterization was done by adopting various electro-analyticaltechniques such as elemental analysis, X-ray Powder Diffraction (XRD), Thermogravimetric Analysis (TGA) and Derivative Thermogravimetry (DTG), Fourier Transform Infrared (FT-IR) Spectrometry, Absorption Spectrophotometry and Ultraviolet-Visible and near Infrared (UV-Vis-NIR). Differential Scanning Calorimetry performed with the heating rate 10 K/min from 297.96 to 770.46 K in normal atmosphere for both mixtures. DSC data indicated that both mixtures A and B are exhibiting exothermic property by their net specific heat capacities (C p ) −11.11 and −2.83 J/g K, respectively. Therefore, these complex mixtures can be utilized as heat dissipation materials. Both mixtures A and B undergo phase change in terms of hydrated phase to dehydrated phase up to 356 and 392 K, respectively. The specific heat capacity of Mixture A during hydration, C p = 2.54 J/g K, is higher than the tin, lead, stainless steel, glass and aluminium at their respective melting points. This mixture is also found better than the commercial product based on lithium ion battery in terms of specific heat capacity. From UV-Vis-NIR analysis, it is found that the mixtures A and B are showing semiconducting behaviour with band gaps 1.66 and 1.68 eV, respectively. The average crystallite sizes of these nano-complex mixtures are 35.29 and 30.94 nm and these were calculated using the Debye-Scherrer equation and Williamson-Hall method.

No abstract

A novel and low‐cost mixture of iron and magnesium have been synthesized and used as selective coatings for flat plate absorber in solar water heating system. The commercial black paint is fabricated with the mixture of composition Fe3(PO4)2·0.1Mg2P2O7·1.9 MgSO4(FPM3A). The composition of the coating mixture has been characterized by various analytical techniques. Thermal studies of these mixtures were accomplished using differential scanning calorimetry and thermo‐gravimetric analysis. From the thermal analysis, it has been observed that the mixtures can be used as thermal heat storage materials. The FPM3A‐modified black paint has been tested in a thermosyphon solar water heater prototype. The average water temperature and efficiency of the flat plate absorber with FPM3A‐modified black paint have increased by an average of 7.5° and around 12%, respectively, in comparison with that with commercial unprocessed black paint.

No abstract

Herein, the synthesis of the novel and inexpensive phosphate mixtures (calcined and non-calcined) of iron (Fe) and sodium (Na) and their application as reflective coating with building envelope materials is reported. The main objective of this work is to determine the effect of hydrated mixtures as a reflective coating. To obtain different hydrated mixtures, samples were synthesized as both calcined and non-calcined mixtures. Various measurement techniques were used to characterize and study the thermal behavior of mixtures. From the thermal behavior of the mixtures, it is noticed that the mixtures can be used as heat-dissipating materials. The average crystallite size was found 40.18 nm and 25.48 nm for the calcined and the non-calcined mixtures, respectively. The calculated band gap for the calcined mixture is 3.71 eV and the non-calcined mixture is 3.73 eV. According to Reddy's equation, the refractive index of the calcined and the non-calcined mixtures is 2.61 and 2.60, respectively. Both the calcined (1A) and the non-calcined (1B) mixtures were fabricated with commercial white paint to develop aesthetic light gray coatings. Both coatings were painted and tested on two building material slabs separately. Then, the highest reflective coating material between these two was painted on a house prototype and tested against commercial gray paint available in the market. An average temperature reduction of 3.8 K was observed in modified gray coating compared to commercial building paint. The reflective coating of the calcined mixture blended with white paint was observed to be better than the non-calcined mixture blended with white paint.