•Experimental performance has been carried for developed solar water heater.•Stearic acid as phase change material has been investigated under both modes.•Proposed system is suitable for domestic & ...industrial applications.•Phase change material integrated manifold is designed for thermal energy storage.•System was investigated with different mass flow rates under both modes.
In this study, the thermal performance of a novel solar collector integrated with stearic acid as phase change material has been investigated. In this design, the solar radiation was collected by heat pipe equipped evacuated tubes and then stored in manifold integrated with phase change material. The stored thermal energy of phase change material then transferred to water flowing through bundle of finned copper pipes placed inside the manifold. In present study, the design, the operating principle and the experimental investigation of the developed system have been presented. The developed system was investigated with different mass flow rates and also discussed the influence of varying mass flow rate on the thermal performance of system. The experimental investigation of designed and developed system has been carried out for two modes i.e. mid-day charging mode and full-day charging mode. It has been observed that for considered mass flow rates, thermal efficiency of the system was varied in the range of approximately 52–62% for full-day charging mode while for mid-day charging mode, it was varied between 55 and 72%. The maximum value of thermal efficiency was approximately 72.52% at mass flow rate of 24 LPH for mid-day charging mode. The efficiency of phase change material for both modes was varied in the range of approximately 61–64%. The annual cost and annual fuel cost of the developed system are much lower than conventional system. Also, the initial capital cost for the developed system can be recovered after 6 years of operation. However, there is no recovery of initial investment for electricity based water heating system.
The proposed system overcomes two problems associated with conventional heat pipe evacuated tube solar collector: elimination of heat pipe overheating problem and low thermal conductivity of phase change materials. By this novel design of manifold, the influence of thermal stratification on the thermal performance of solar collectors can be completely eradicated.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPUK, ZAGLJ, ZRSKP
•Sep/FAEM(42%) composite as FSt-CPCMs show no liquid FAEM leakage.•FSt-CPCM has proper melting temperature (22.86 °C) and relatively high latent heat capacity (76.16 J/g).•FSt-CPCM showed good TES ...reliability, chemical stability and thermal durability.•FSt-CPCM can be adapted to traditional construction materials for temperature controlling of building spaces.•Its cement plaster form exhibited appreciated thermoregulation performance.
Thermal energy storage (TES) properties of form-stabilized Sepiolite(Sep)/Fatty acid eutectic composite PCM(FAEM) and temperature control performance of its cement based-plaster in laboratory scale were investigated. The eutectic mixture of capric acid(CA) and stearic acid(SA) recognized as FAEM was infiltrated by Sep by direct impregnation method. The Sep/FAEM(42%) composite PCM developed in stabilized form was characterized by SEM, FTIR and XRD analysis techniques. The DSC results exhibits that the produced form-stabilized composite PCM (FSt-CPCM) had proper melting temperature (22.86 °C) and relatively high latent heat capacity (76.16 J/g) for thermal regulation targets of building spaces. The FSt-CPCM showed outstanding chemical stability and TES reliability although it was exposed to 1000 melt/freeze cycles. In addition, cement plaster containing FSt-CPCM exhibited appreciated temperature control performance in laboratory scaled-test room compared to ordinary cement plaster. It was concluded from this finding that the produced Sep/FAEM/Cement composite plaster can be evaluated a beneficial material for indoor temperature regulation and energy saving in building envelopes.
Thermal energy storage properties of sepiolite(Sep) clay/CA–SA eutectic mixture developed as novel FSt-CPCM was investigated. The DSC results exhibits that the produced FSt-CPCM has proper melting temperature (22.86 °C) and relatively high latent heat capacity (76.16 J/g) for thermal regulation of building spaces. The cement plaster form of the FSt-CPCM exhibited appreciated temperature control performance in laboratory scaled-test room compared to ordinary cement plaster. Display omitted .
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
An experimental study was performed to evaluate the comparative efficiency of bio-flocculant (waste egg shell), laboratory available calcium carbonate (LACC) and alum (Al2 (SO4)3) for harvesting of ...unicellular microalga, Chlorella pyrenoidosa. The influence of pH on zeta potential (ζ) was also studied to explain the chemistry of flocculation process. The maximum harvesting efficiency (99%) was obtained with alum with deformities in algal cell surfaces. Waste egg-shell material is developed as a low-cost bio-flocculant for harvesting of Chlorella pyrenoidosa using 100 mg egg-shell bio-flocculant/L and 100 mg LACC/L, zeta potential analysis was completed to further understand the chemistry of harvesting efficiency over the different ranges of pH (2.0, 4.0, 6.0, 8.0, and 10.0). The optimized range for harvesting efficiency (HE) of pH is 4.0–8.0 for both flocculants. Maximal harvesting efficiency was achieved at pH 4.0 (99%) and pH 8.0 (95%) with bio-flocculant and LACC respectively. Hence, bio-flocculant based harvesting method is found as the best way to dewatering the algal biomass from aqueous medium with entire and intact algal cell surface with environment friendly and cost-effective approach.
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•Harvesting of C. pyrenoidosa at optimized pH with flocculants at 100 mg/L•Impact of zeta potential & pH investigated on harvesting efficiency (HE).•Comparative analysis for HE with different flocculants at pH (2,4,6,8,10).•ζ is pH dependent, decrease in zeta value as the pH increases.•Sustainable chemistry between ζ & pH for harvesting of algae with bioflocculant.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Polyethylene glycol (PEG) is one the most promising organic phase change materials (PCMs) due to good latent heat thermal energy storage (LHTES) characteristics. However, leakage issue in melting ...state and low thermal conductivity restrict its further real applications. In order to eliminate these disadvantages as well as increasing its incorporation ratio, polyethylene glycol (PEG600) was impregnated with raw diatomite (RD)/carbon nanotubes(CNTs) pre-composites. Without exhibiting melt leakage, PEG was successfully confined as 42.8, 44.5 and 51.7 wt% in the novel shape-stabilized composite phase change materials (S-SCPCMs) including 0.57, 1.70 and 2.50 wt% CNTs while it was absorbed by RD as 41.0 wt%. The chemical and morphological characterizations of the produced S-SCPCMs were made by FT-IR and SEM techniques. The DSC analysis showed that the S-SCPCMs had melting temperatures in the range of about 7–8°C and latent heat capacity between 53.8 and 62.9 J/g. Moreover, compared to the RD/PEG composite, the thermal conductivities of RD/CNTs/PEG composites were enhanced between 73% and 93% as well as the latent heat capacity of them was increased in the range of 5–31%. The melting times and total heating times of the S-SCPCMs were drastically shortened depending on the improvement in thermal conductivity of them. Thermal cycling test and TGA results demonstrated that the S-SCPCMs had commendable long-term chemical stability, LHTES reliability and thermal durability. Consequently, the loading of CNTs to RD/PEG composite provided beneficial outcomes such as increasing impregnation ratio with no liquid leakage, reducing heat storing/releasing periods depending on enhanced thermal conductivity, without damaging chemical stability and thermal durability. In view of these advantageous properties, the S-SCPCMs can be incorporated with ordinary structural elements to generate various building sections with solar energy harvesting/releasing capability. Such combinations can be also evaluated for passive solar cooling purposes in radiant floor heating systems, insulation and ceiling panels or walls depending on the climatic circumstances.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
In this paper, we produced new kind cement mortars with thermal energy storing/releasing properties, containing silica fume (SF)/capric acid-stearic acid eutectic mixture (CA-SA) as form-stable ...composite phase change material (FSC-PCM). The physicochemical compatibility between CA-SA eutectic PCM and SF was studied by fourier-transform infrared (FTIR), X-ray powder diffraction (XRD) and scanning electron microscope (SEM) techniques. The differential scanning calorimetry (DSC) results indicated that the FSC-PCM including 37 wt% CA-SA eutectic PCM has a phase change temperature and latent heat capacity of 23.28 °C and 65.6 J/g, respectively. Thermogravimetric (TG) measurements and thermal cycling examination demonstrated that FSC-PCM has great stability in terms of its chemical structure, thermal degradation and cycling reliability in LHTES properties. To achieve novel type cementations composite mortar, the FSC-PCM was replaced with ordinary cement mortar (OCM) in weight fraction of 10%, 15% and 20%. Thermoregulation performance test showed that the maximum indoor temperatures differences between the OCM and latent heat storage-cement mortar (LHS-CM) based rooms were found as 2.48 °C during the heating stage and 1.71 °C during the cooling stage. Mechanical test findings of the LHS-CMs showed acceptable mechanical properties and have suitable properties for regulation of indoor temperatures and reducing energy consumption in buildings.
•SF/CA-SA was characterized as novel form-stable composite PCM (FSC-PCM) >.•The FSC-PCM has melting temperature and latent heat of 23.28 °C and 65.61 J/g >.•LHS-CM 3 sample including 20 wt% FSC-PCM showed adequate mechanical properties >.•LHS-CM 3 sample released good thermal regulation performance >.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The purpose of this experimental study is to determine the thermal and chemical reliability of organic phase change materials (O-PCMs) viz. paraffin, palmitic acid, and myristic acid for 1500 ...accelerated melt/freeze. The differential scanning calorimeter (DSC) was used to measure the melting temperature and the latent heat of fusion at zeroth cycle and after 100th, 500th, 1000th, and 1500th thermal cycles. The DSC results show the gradual changes in the value of thermophysical properties of all the tested PCMs. The changes in melting temperature of paraffin, palmitic acid, and myristic acid have been found in the range of +0.72 to +3.27, −0.29 to +1.76, and −2.09 to +1.5 °C, respectively, and the latent heat of fusion in −9.8 to 14.2, 3.3 to 17.8, and 0.9 to 9.7 %, respectively. The Fourier transform and infrared spectroscopy (FT-IR) technique was used to investigate the changes in the compositional/functional group of the O-PCMs before and after thermal cycles. The FT-IR spectrum confirms the chemical stability during the thermal cycle test. The experimental results show that these organic PCMs possess a good thermal reliability in terms of melting temperature and the latent heat of fusion and chemical stability during thermal cycle testing.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
A sustainable approach to ensuring the thermal regulation of space is reliable with phase change materials (PCMs) operating at 15–25 °C. Henceforth, there is a need of a search of binary and ternary ...eutectic PCMs operating at desirable phase transition temperatures of 15–25 °C, high energy storage enthalpy (180–220 J/g), improved thermal conductivity and better absorptivity of solar energy. In this current research, we developed a ternary eutectic inorganic salt hydrate PCM intended for a low-temperature thermal regulation system. Based on the eutectic melting point theory, the phase transition temperature and proportion of sodium carbonate decahydrate (SCD), sodium phosphate dibasic dodecahydrate (SPDD) and sodium sulphate decahydrate (SSD) were determined. As per the calculated proportion, ternary eutectic PCM was experimentally prepared. Furthermore, to enhance the thermal property, graphene nanoplatelets (GNP) were dispersed at weight concentrations of 0.4%, 0.7% and 1.0%. The prepared nanoparticle-dispersed PCMs were characterized using an optical microscope, Fourier transform infrared (FT-IR) spectroscopy and a thermal conductivity meter, and a differential scanning calorimeter (DSC) was used to evaluate the morphology, chemical stability and thermal properties. The results showed increases in thermal conductivity and optical absorbance by 71.5% and 106.5%, respectively, with GNP at 1.0% weight concentration. Similarly, the degree of supercooling and transmissibility was reduced by 43.5% and 76.2% correspondingly. The prepared composite PCM is expected to contribute towards cooling, with an intention to contribute towards sustainable development.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
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•Treatment of slaughterhouse wastewater (SHWW) with Chlorella pyrenoidosa.•Maximized growth observed with 50% concentration in 430 mgL−1 of biomass (dry wt.)•COD, NO3– and PO4−3 ...reduction ≈17–31%, 23–42%, 18–48% with 50% concentration of SHWW.•Correlation analysis investigation in between parameters of SHWW and algal strain.•SHWW treatment with Chlorella supports pollutant reduction and biochemical profiles.
Slaughterhouse produce large amount of wastewater, containing high pollutant load in terms of protein, fats and meat pieces, might lead to source of non-point contamination. Various concentrations (25%, 50%, 75%, and 100%) of slaughterhouse wastewater were used to increase the algal biomass production, pollutants removal and biochemical profile analysis under controlled conditions of C. pyrenoidosa. Results showed that the maximum biomass yield 430 mg L−1 was achieved at 50% concentration of wastewater to other concentration of wastewater. Direct relation was observed in between pollution load and nutrient load of SHWW with biochemical profile of C. pyrenoidosa. The COD/BOD ratio (1.9) was found to be significant on the scale of degradability by algal biomass. Sufficient nutrient removal efficiencies (23–42%, 18–48%) and pollutant load efficiencies (17–31%, 7–29%) were observed. Findings showed that slaughterhouse wastewater is rich in nutrients, which can be utilized for algal biomass production and wastewater remediation for future endeavors.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Integration of a building mass with a phase change-energy storage material is able to improve its thermal efficiency. With this respect, pumice was evaluated as low-cost supporting material for ...development of energy-efficient composites containing capric acid (CA) and polyethylene glycol(PEG) as phase change material (PCM). The developed leak-proof composites was also incorporated separately with ordinary cement (OC; Portland Cement) to produce novel plaster with thermal energy storage (TES) ability for thermoregulation of buildings. The DSC analysis results demonstrated that the shape-stabilized composite PCMs (S-SCPCMs) had melting temperatures of 31.03 °C and 8.80 °C and TES capacity of 116.27 J/g and 98.39 J/g, respectively. Cycling thermal degradation stability and TES dependability of the leak proof composites were examined by TGA techniques. The lab-scale test revealed that the indoor center temperatures (ICT) of the cubic chambers plastered separately by pumice/CA/OC and pumice/PEG/OC mortars were maintained at comfortable temperature range for relatively longer times compared to the control chamber plastered by OC mortar.
•The pumice/CA(62 wt%) and pumice/PEG(56 wt%) were fabricated as S-SCPCMs.•The S-SCPCMs have melting temperature of 8.80 and 31.03 °C, respectively.•The S-SCPCMs have relatively high TES capacity of 98.39 and 116.27 J/g, respectively.•The S-SCPCMs have good thermal durability and cycling chemical/thermal stability.•The S-SCPCM/cement plasters showed remarkable thermoregulation performance.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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•Novel nanocomposite prepared using paraffin wax and polyaniline.•Improved latent heat and thermal conductivity of PWP-1 by 8.2 and 46.8% respectively.•Solar light transmission of PWP ...reduced by ~78% relative to paraffin wax.•After 200 thermal cycles, latent heat value of PWP-1 is greater than paraffin wax.
An energy source is required that has potential to reduce global warming, energy cost and create environmental sustainability. Solar energy is a viable candidate with 120 petajoules of energy on earth per second. To utilize this energy the present research explores the effect of the addition of conducting polyaniline (PANI) and cupric (II) oxide (CuO) nanoparticles within the matrix of paraffin wax. The Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analyzer (TGA), Differential Scanning Calorimetry (DSC), Ultraviolet–Visible-Near Infrared Spectrometer (UV–VIS) and thermal conductivity characterization of the prepared composite were performed. An enhancement of latent heat capacity of paraffin/PANI nanocomposite by 8.20% and paraffin/CuO composite by 7.81% was observed. Thermal conductivity of Paraffin/PANI was increased by ~46.8% for a 1% weight concentration of PANI in paraffin wax the same concentration as maximum latent heat capacity. In the case of paraffin/CuO composite, the maximum increment of thermal conductivity was found to be ~63.6%. To check the thermal reliability of the formulated nanocomposite, the base paraffin and nanocomposites were subjected to thermal cycling of 200 cycles. The DSC results showed that paraffin/PANI nanocomposite outperformed both base paraffin wax and paraffin/CuO composite. With comparable thermal conductivity to Paraffin/CuO composite, better latent heat capacity and improved thermal reliability Paraffin/PANI composite results are encouraging for the application in solar application area.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
