Effect of Cover Inclination and Water Depth on Performance of a Solar Still for Indian Climatic Conditions

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Anil Kr. Tiwari ◽  
G. N. Tiwari
Keyword(s):  
Convective Heat ◽  
Water Depth ◽  
Convective Heat Transfer Coefficient ◽  
Climatic Conditions ◽  
New Delhi ◽  
Solar Still ◽  
Transfer Coefficients ◽  
Distillate Yield ◽  
Passive Solar Still ◽  
Indian Climatic

Effects of condensing cover inclination and water depth on the convective heat transfer coefficient and yield have been studied for a passive solar still. Three solar stills with an effective basin area of 1m2 each have been studied for three inclinations of condensing cover, namely, 15deg, 30deg, and 45deg. An identical solar still, but with a fixed cover inclination of 30deg, has also been tested to evaluate the effects of varying water depth. Outdoor experiments have been conducted for New Delhi climatic conditions (28°37′N∕77°13′E). Hourly variations of temperatures (water, vapor, and cover) and of distillate yield have been recorded and analyzed to determine convective heat and mass transfer coefficients. The resulting calculative extrapolation of experimental data from clear-day operation shows that the combination of minimum water depth and 15deg inclination of the condensing cover leads to maximum annual distillate yield for the climatic conditions of New Delhi. However, a cover inclination of 45deg is almost equally effective on an annual basis, but with better winter performance.

Enhancement in Exergoeconomic and Enviroeconomic Parameters for Single Slope Solar Still by Incorporating N Identical Partially Covered Photovoltaic Collectors

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
Desh B. Singh ◽  
Navneet Kumar ◽  
Sanjay Kumar ◽  
Vijay K Dwivedi ◽  
Jeetendra K Yadav ◽  
...  
Keyword(s):  
Flow Rate ◽  
Water Depth ◽  
Unit Cost ◽  
Climatic Conditions ◽  
Environmental Cost ◽  
New Delhi ◽  
Solar Still ◽  
Monetary Value ◽  
Compound Parabolic Concentrator ◽  
Better Than

This paper deals with the enhancement in exergoeconomic and enviroeconomic parameters for single-slope solar still by incorporating N identical partially covered photovoltaic thermal (PVT) collectors. Three cases: (a) single slope solar still incorporating N identical partially covered PVT flat plate collectors (FPC) (N-PVT-FPC-SS), (b) single slope solar still incorporating N identical partially covered PVT compound parabolic concentrator collectors (N-PVT-CPC-SS), and (c) conventional single slope solar still (CSSSS) have been taken to assess the improvement in various parameters. The various parameters have been computed at 0.14 m water depth, selected values of mass flow rate, and number of collectors considering four climatic conditions of New Delhi for each month of year. It has been concluded that N-PVT-FPC-SS performs best followed by N-PVT-CPC-SS and CSSSS on the basis of exergoeconomic and enviroeconomic parameters; however, CSSSS performs better than N-PVT-FPC-SS and N-PVT-CPC-SS on the basis of productivity measured in terms of ratio of monetary value of output and input. The kWh per unit cost based on exergoeconomic parameter is higher by 45.11% and 47.37%; environmental cost is higher by 65.74% and 90.02%; however, the output per unit input based on productivity is higher by 12.09% and lower by 26.83% for N-PVT-FPC-SS than N-PVT-CPC-SS and CSSSS, respectively.

scholarly journals Analytical thermal modeling of double slope solar still by using inner glass cover temperature

2008 ◽  
Vol 12 (3) ◽  
pp. 139-152 ◽  
Author(s):  
Kumar Shukla ◽  
Ajeet Rai
Keyword(s):  
Internal Heat ◽  
Climatic Conditions ◽  
Solar Still ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Glass Cover ◽  
Solar Distillation ◽  
Indian Climatic ◽  
C And N ◽  
Internal Heat Transfer

In this paper, expressions for water and glass temperatures, hourly yield and instantaneous efficiency for double slope solar distillation systems have been derived analytically. The analysis is based on the basic energy balance for the systems. A thermal model has been developed to predict the performance of the still based on both, the inner and the outer glass temperatures of the solar still. In the present work two sets of values of C and n of internal heat and mass transfer coefficients, obtained from the experimental data under Indian climatic conditions, have been used. It is concluded that (1) there is a significant effect of operating temperature range on the internal heat transfer coefficients and (2) by considering the inner glass cover temperature there is reasonable agreement between the experimental and predicted theoretical results.

Influence of Various Basin Types on Performance of Passive Solar Still: A Review

2021 ◽  
Vol 10 (4) ◽  
pp. 789-802
Author(s):  
Tri Hieu Le ◽  
Minh Tuan Pham ◽  
H Hadiyanto ◽  
Van Viet Pham ◽  
Anh Tuan Hoang
Keyword(s):  
Water Depth ◽  
Thermal Efficiency ◽  
Tracking System ◽  
Design Parameters ◽  
Cylindrical Shape ◽  
Solar Still ◽  
Practical Utilization ◽  
Passive Solar Still ◽  
Passive Solar ◽  
The Impact

Passive solar still is the simplest design for distilling seawater by harnessing solar energy. Although it is undeniable that solar still is a promising device to provide an additional freshwater source for global increasing water demand, low thermal efficiency along with daily distillate yield are its major disadvantages. A conventional solar still can produced 2 to 5 L/m2day. Various studies have been carried out to improve passive solar stills in terms of daily productivity, thermal efficiency, and economic effectiveness. Most of the researches that relate to the daily output improvement of passive solar still concentrates on enhancing evaporation or/and condensation processes. While the condensation process is influenced by wind velocity and characteristics of the condensed surface, the evaporation process is mainly affected by the temperature of basin water. Different parameters affect the brackish water temperature such as solar radiation, design parameters (for example water depth, insulators, basin liner absorptivity, reflectors, sun tracking system, etc). The inclined angle of the top cover is suggested to equal the latitude of the experimental place. Moreover, the decrease of water depth was obtained as a good operational parameter, however, the shallow water depth is required additional feed water for ensuring no dry spot existence. Reflectors and sun-tracking systems help solar still absorb as much solar intensity as possible. The internal reflector can enhance daily yield and efficiency of stepped solar still up to 75% and 56% respectively, whereas, passive solar still with the support of a sun-tracking system improved daily yield up to 22%. Despite large efforts to investigate the impact of the different parameters on passive solar distillation, the effect of the basin liner (including appropriate shapes and type of material), needs to be analyzed for improvement in practical utilization. The present work has reviewed the investigation of the solar still performance with various types of basin liner. The review of solar stills has been conducted critically with rectangular basin, fins basin, corrugated basin, wick type, steps shape, and cylindrical shape basin with variety of top cover shapes. The findings from this work conclude that the basin liner with a cylindrical shape had better performance in comparison with other metal types and provides higher freshwater output. Stepped type, inclined, fin absorber, and corrugated shapes had the efficient performance.  Further exploration revealed that copper is the best-used material for the productivity of passive solar still.

Effect of series and parallel combination of photovoltaic thermal collectors on the performances of integrated active solar still

2021 ◽  
pp. 1-28
Author(s):  
G N Tiwari ◽  
Md Meraj ◽  
M.E. Khan ◽  
V K Dwevedi
Keyword(s):  
Water Depth ◽  
Electrical Energy ◽  
Solar Still ◽  
Packing Factor ◽  
Pv Module ◽  
Parallel Arrangement ◽  
Passive Solar Still ◽  
In Series ◽  
Parallel Case ◽  
Operating Temperature Range

Abstract In this paper, an analytical expression for hourly yield, electrical energy and overall exergy of self-sustained solar still integrated with series and parallel combination of photovoltaic thermal-compound parabolic concentrator (PVT-CPC) collectors have been derived. Based on numerical computations, it has been observed that the yield is maximum for all self-sustained PVT-CPC collectors are connected in series [case (i)]. Further, the daily yield and exergy increase with the increase of water depth unlike passive solar still for all collectors connected in series. However, overall exergy decreases with an increase of water depth for all collectors connected in parallel [case (iv)]. For numerical simulations, the total numbers of self-sustained PVT-CPC collectors has been considered as constant. Further, an effect of series and parallel combination of PVT-CPC collectors on daily yield, electrical energy and overall exergy have also been carried out. Following additional conclusions have also been drawn: (i) The daily yield of the proposed active solar still decreases with the increase of packing factor of semi-transparent PV module for a given water depth and electrical energy and overall exergy increase with water depth for case (i) as expected due to low operating temperature range at higher water depth in the basin. (i) The daily yield, electrical energy and overall exergy increase with the increase of water depth for all combination of series and parallel arrangement of PVT-CPC collectors for a packing factor of 0.22 as per our expectation.

scholarly journals CONVECTIVE HEAT TRANSFER CHARACTERISTICS OF AQUEOUS TiO2 NANOFLUID UNDER LAMINAR FLOW CONDITIONS

2008 ◽  
Vol 07 (06) ◽  
pp. 325-331 ◽  
Author(s):  
S. M. SOHEL MURSHED ◽  
KAI CHOONG LEONG ◽  
CHUN YANG ◽  
NAM-TRUNG NGUYEN
Keyword(s):  
Heat Transfer ◽  
Laminar Flow ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Volume Fraction ◽  
Convective Heat Transfer Coefficient ◽  
Transfer Coefficients ◽  
Enhancement Of Heat Transfer ◽  
Heat Transfer Coefficients ◽  
Constant Wall Heat Flux

This paper reports an experimental investigation into force convective heat transfer of nanofluids flowing through a cylindrical minichannel under laminar flow and constant wall heat flux conditions. Sample nanofluids were prepared by dispersing different volumetric concentrations (0.2–0.8%) of nanoparticles in deionized water. The results showed that both the convective heat transfer coefficient and the Nusselt number of the nanofluid increase considerably with the nanoparticle volume fraction as well as the Reynolds number. Along with the enhanced thermal conductivity of nanofluids, the migration, interactions, and Brownian motion of nanoparticles and the resulting disturbance of the boundary layer are responsible for the observed enhancement of heat transfer coefficients of nanofluids.

scholarly journals Determination of Heat Transfer Coefficients Over Ribbed Surfaces With Infrared Thermography

1997 ◽  
Author(s):  
Francisco P. Brójo ◽  
Luís C. Gonçalves ◽  
Pedro D. Silva
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Heat Transfer Coefficient ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Convective Heat Transfer Coefficient ◽  
Stanton Number ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients

The scope of the present work is to characterize the heat transfer between a ribbed surface and an air flow. The convective heat transfer coefficients, the Stanton number and the Nusselt number were calculated in the Reynolds number range, 5.13 × 105 to 1.02 × 106. The tests were performed inside a turbulent wind tunnel with one roughness height (e/Dh = 0.07). The ribs had triangular section with an attack angle of 60°. The surface temperatures were measured using an infrared (IR) thermographic equipment, which allows the measurement of the temperature with a good spatial definition (10.24 × 10−6 m2) and a resolution of 0.1°C. The experimental measures allowed the calculation of the convective heat transfer coefficient, the Stanton number and the Nusselt number. The results obtained suggested a flow pattern that includes both reattachment and recirculation. Low values of the dimensionless Stanton number, i.e. Stx*, are obtained at the recirculation zones and very high values of Stx* at the zones of reattachment. The reattachment is located at a dimensionless distance of 0.38 from the top of the rib. That distance seems to be independent of the Reynolds number. The local dimensionless Stanton number remains constant as the Reynolds number varies. The convective heat transfer coefficient presents an uncertainty in the range of 3 to 6%.

scholarly journals Influence of environmental boundary conditions on convective heat transfer coefficients of wall internal surface

2021 ◽  
Vol 312 ◽  
pp. 02012
Author(s):  
Tullio de Rubeis ◽  
Luca Evangelisti ◽  
Claudia Guattari ◽  
Roberto De Lieto Vollaro ◽  
Francesco Asdrubali ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Convective Heat Transfer Coefficient ◽  
Internal Surface ◽  
Heat Fluxes ◽  
Transfer Coefficients ◽  
Air Speed ◽  
Velocity Changes ◽  
Forced Air

In this study, convective heat transfer phenomena were investigated by means of a Guarded Hot Box (GHB) apparatus. An experimental setup characterized by air and surface temperature probes, and a hot-wire anemometer was used. Five small fans were installed in the metering chamber to generate a forced air flow characterized by different velocity values. So, the GHB was used for investigating the influence of different air speed values on internal convective coefficients. Considering horizontal heat fluxes, an internal convective coefficient values of 2.5 W/m2K is reported in the Standard ISO 6946. However, no exhaustive description about this value is provided. The aim of this work is to experimentally determine the internal thermal surface resistance, quantifying how the convective heat transfer coefficient varies as air velocity changes.

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