ANALYSIS OF THE THERMAL EFFICIENCY OF A SOLAR THERMAL COLLECTOR FOR LOW-INCOME FAMILIES

Author(s):  
Julia Maria Massareli Costa ◽  
Guilherme Viana ◽  
Vinicius Cruz ◽  
Felipe Boragina da silva ◽  
Ana Beatriz Valentin ◽  
...  
2017 ◽  
Vol 21 (6 Part B) ◽  
pp. 2769-2779 ◽  
Author(s):  
Gianpiero Colangelo ◽  
Marco Milanese ◽  
Risi de

Investigations on the potential thermal efficiency of an innovative nanofluid solar thermal collector have been performed using a commercial software (RadTherm ThermoAnalytics rel. 10.5). The Al2O3-nanofluid has been simulated as working fluid of the solar thermal collector, varying the nanoparticles concentration from 0%vol of Al2O3 nanoparticles (pure water) up to 3%vol of Al2O3 of nanoparticles. The numerical model has been validated with experimental data, obtained with a real prototype of the simulated solar thermal collector. Real thermal properties of the nanofluids at different concentrations have been used in the simulations. The boundary conditions used for the simulations have been those of real weather conditions. An increase in thermal efficiency (up to 7.54%) has been calculated using nanofluid with a volume fraction of 3% and the influence of nanoparticles concentration on the thermal performance of the solar collector has been pointed out.


Energies ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2661 ◽  
Author(s):  
Sang-Myung Kim ◽  
Jin-Hee Kim ◽  
Jun-Tae Kim

A photovoltaic thermal (PVT) system is a technology that combines photovoltaics (PV) and a solar thermal collector to produce thermal energy and generate electricity. PVT systems have the advantage that the energy output per unit area is higher than the single use of a PV module or solar thermal collector, since both heat and electricity can be produced and used simultaneously. Air-based PVT collectors use air as the heat transfer medium and flow patterns are important factors that affect the performance of the PVT collector. In this study, the thermal and electrical performance and characteristics of an air-based PVT collector were analyzed through experiments. The PVT collector, with bending round-shaped heat-absorbing plates, which increase the air flow path, has been developed to improve the thermal performance. The experiment was done under the test conditions of ISO 9806:2017 for the thermal performance analysis of an air-based PVT collector. The electrical performance was analyzed under the same conditions. In the results, it can be found that the inlet flow rate of the PVT collector considerably affects the thermal efficiency. It was analyzed that as the inlet flow rate increased from 60 to 200 m3/h, the thermal efficiency increased from 29% to 42%. Then, the electricity efficiency was also analyzed, where it was determined that it was improved according to operating condition of PVT collector.


2014 ◽  
Vol 84 (5-6) ◽  
pp. 244-251 ◽  
Author(s):  
Robert J. Karp ◽  
Gary Wong ◽  
Marguerite Orsi

Abstract. Introduction: Foods dense in micronutrients are generally more expensive than those with higher energy content. These cost-differentials may put low-income families at risk of diminished micronutrient intake. Objectives: We sought to determine differences in the cost for iron, folate, and choline in foods available for purchase in a low-income community when assessed for energy content and serving size. Methods: Sixty-nine foods listed in the menu plans provided by the United States Department of Agriculture (USDA) for low-income families were considered, in 10 domains. The cost and micronutrient content for-energy and per-serving of these foods were determined for the three micronutrients. Exact Kruskal-Wallis tests were used for comparisons of energy costs; Spearman rho tests for comparisons of micronutrient content. Ninety families were interviewed in a pediatric clinic to assess the impact of food cost on food selection. Results: Significant differences between domains were shown for energy density with both cost-for-energy (p < 0.001) and cost-per-serving (p < 0.05) comparisons. All three micronutrient contents were significantly correlated with cost-for-energy (p < 0.01). Both iron and choline contents were significantly correlated with cost-per-serving (p < 0.05). Of the 90 families, 38 (42 %) worried about food costs; 40 (44 %) had chosen foods of high caloric density in response to that fear, and 29 of 40 families experiencing both worry and making such food selection. Conclusion: Adjustments to USDA meal plans using cost-for-energy analysis showed differentials for both energy and micronutrients. These differentials were reduced using cost-per-serving analysis, but were not eliminated. A substantial proportion of low-income families are vulnerable to micronutrient deficiencies.


2001 ◽  
Author(s):  
Trish Livingstone ◽  
Lisa Lix ◽  
Mary McNutt ◽  
Evan Morris ◽  
William Osei ◽  
...  

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