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Performance Analysis of Flat Plate Solar Collector using Al2O3/Distilled Water Nanofluid: An Experimental Investigation
摘要： Owing to how effectively it can convert solar energy into usable form, solar thermal technology has gained a lot of importance during the recent years. Heat exchangers, refrigeration, air conditioning, material science engineering, etc. are the biggest proponents incorporating solar technology along with nano particles for their high thermal conductivity. This study concerns with the effect of water based Al2O3 Nano fluid on the performance of solar water heater- Flat plate type. In the study, the dispersion quality of nanoparticles in fluid was enhanced using high quality surfactant sodium dodecyl sulfate (SDS). The experiments were conducted at Amity University Rajasthan, Jaipur, India (27.1721° N, 75.9542° E) which has an annual average solar irradiance 5.56 kWh/m2/day. Different conditions like flow rate, pressure, climatic conditions, time, solar collector inclination angle, composition of Nano fluid etc. were tested. The Al2O3 concentration varied from 0.1 to 0.3 vol. percentage. The tests were performed at different mass flow rates 1-3 LPM. The measured values of the thermal conductivity in the range of 0.610-0.622 W/m-k. Results indicated that by increasing the volume fraction of Al2O3 from 0.1% to 0.3%, there is a 21.32% growth in collector efficiency.
关键词： Nanofluids,Solar collector-flat plate type,Solar Energy,Collector Efficiency
更新于2025-09-16 10:30:52
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Effect of vacuum deterioration on thermal performance of coaxial evacuated tube solar collector considering single and two phase flow modelling: A numerical study
摘要： Boiling and condensation play an important role in heat transfer in evacuated tube solar collectors (ETC), especially for low flow rates. Another factor that influences the efficiency of an ETC is deterioration of vacuum inside the ETC. The present study investigates numerically the effect of deteriorating vacuum during single and two phase flows inside an ETC to analyze its thermal performance. A steady-state one-dimensional model is developed which can simulate the steady-state thermal performance of the Evacuated tube solar collector (ETC) with single and two-phase flows under saturation conditions considering effects of vacuum deterioration to simulate a more real-life situation of solar collectors. The rise in pressure inside the ETC has a significant effect on the suppression of boiling and condensation due to rise in overall heat loss coefficient. The radiative, convective and conductive heat loss coefficients from the collector are studied for gradual pressure rise inside the ETC. The two phase model also indicates that if boiling starts inside the ETC in a particular inlet flow condition, consideration of two phase flow along with the effect of vacuum deterioration shows significant deviation of efficiency and temperature profile from those of single phase flow models and predicts more accurate results. Inducing of two-phase heat transfer in ETC, with all the fluid condensing again within the collector tube, will result in improved efficiency for that range of mass flow rates. It also helps in maintaining uniform temperature and equal heat gain throughout the collector absorber plate. The efficiency of the collector for higher inlet temperatures is seen to be effected more significantly by vacuum deterioration than at lower inlet temperatures in single phase flows. However, in two phase flows for a fixed saturation temperature of the fluid, vacuum deterioration has negligible effect on the efficiency at higher inlet temperatures (Tfi ≥ 85 °C).
关键词： Evacuated tube solar collector,Collector efficiency,Vacuum deterioration,Two phase flows
更新于2025-09-10 09:29:36
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Diagnostic method of solar thermal system based on the short time on-line measurements
摘要： This paper presents the method of a solar heating system diagnostics allowing determination of the following coefficients in operating conditions: heat loss coefficient ULK, collector efficiency factor F’ and heat removal factor FR related to the collector static properties, effective heat capacity (mc)e and time-constant Tz related to the collector dynamic properties. The proposed method is based on a comparison of two models: analytical and numerical. The analytical model was developed based on the collector energy balance and that combining characteristic parameters. The numerical model was developed based on the recorded operating data of the medium inlet and outlet temperature, and solar irradiance. The condition necessary to apply this method covers constant volume flow rate of the medium in the system during the experiment.
关键词： time-constant,parametric identification,solar collector,efficiency characteristics
更新于2025-09-10 09:29:36
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Efficiency of evacuated tube solar collector using WO3/Water nanofluid
摘要： The thermal performance of the evacuated tube solar collector with WO3/Water Nanofluid was studied in this paper. The WO3 nanoparticles were spherical with 90 nm diameter Three different volume fraction of WO3 nanoparticles of 0.014%, 0.028%, and0.042% were examined at several mass flux rates of 0.013 kg/s.m2, 0.015 kg/s.m2 and 0.017 kg/s.m2. The stability of the nanofluid was checked. Experiments were performed in Budapest, Hungary on the latitude of 47°280N and longitude of 19°030E. The results showed that the temperature difference of the fluid increased up to 21% with adding WO3 nanoparticles. The maximum heat gain at the solar irradiance of 900 W/m2 was raised up to 23% when WO3 nanoparticles were used. The proportion of the growth of the heat removable factor for nanofluids comparing to water at the same mass flux rate is between 1.05 and 1.16. The results indicated that the efficiency of the evacuated tube solar collector enhanced with more nanoparticles added. The thermal-optical efficiency of the evacuated tube solar collector reached 72.8%.
关键词： WO3/Water nanofluid,Solar collector,Efficiency,Evacuated tube
更新于2025-09-04 15:30:14