Enhancement of modified solar still integrated with external condenser using nanofluids: An experimental approach

doi:10.1016/j.enconman.2013.11.013

Energy Conversion and Management

Volume 78, February 2014, Pages 493-498

https://doi.org/10.1016/j.enconman.2013.11.013 Get rights and content

Highlights

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The effect of using nanofluids on the solar still performance is investigated.
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The solar still with external condenser increases the productivity by about 53.2%.
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Using nanofluids improves the solar still water productivity by about 116%.

Abstract

The distilled water productivity of the single basin solar still is very limited. In this context, the design modification of a single basin solar still has been investigated to improve the solar still performance through increasing the productivity of distilled water. The experimental attempts are made to enhance the solar still productivity by using nanofluids and also by integrating the still basin with external condenser. The used nanofluid is the suspended nanosized solid particles of aluminum-oxide in water. Nanofluids change the transport properties, heat transfer characteristics and evaporative properties of the water. Nanofluids are expected to exhibit superior evaporation rate compared with conventional water. The effect of adding external condenser to the still basin is to decrease the heat loss by convection from water to glass as the condenser acts as an additional and effective heat and mass sink. So, the effect of drawn vapor at different speeds was investigated. The results show that integrating the solar still with external condenser increases the distillate water yield by about 53.2%. And using nanofluids improves the solar still water productivity by about 116%, when the still integrated with the external condenser.

Introduction

In the last 40 years, the problem of freshwater shortage has been one of the main challenges in the world. Potable water not only is important for life but also for industrial and agricultural purposes. So, the life without water will be impossible. The origin and continuation of mankind is based on water. Although more than 75% of the earth covered with water, only 0.014% of that can be used directly for the human being and other organisms. On the other hand, sea water constitutes 97.5% of global water, so it can be used for those purposes by converting it to distilled water [1]. There are some techniques for water purification, which among them, solar water distillations is an attractive subject. A single basin solar still is a very simple solar device used for converting available brackish or waste water into potable water. The solar distillation systems are mainly classified into two categories: passive and active solar still. In passive solar stills, solar radiation is the only parameter which affects evaporation, but in active solar stills by using the additional device such as fan [2], pump [3], sun tracking system [4] or solar collectors [5], [6], [7], the temperature difference between evaporating and condensing area is increased, and consequently enhancement on productivity is achieved. Active solar stills also can use waste heat of other processes or devices to improve the evaporation rate of water. Productivity of such solar stills is very low. The efficiency of a conventional single-basin solar still is usually about 30–40% [8]. This is because of the loss of the heat of condensation to the environment through the glass cover of the basin and some useful heat carried away by the warm condensate.

Many extensive studies have been carried out to enhance productivity, effectiveness and efficiency of single-basin solar stills. Solar still with sponge cubes in basin is studied by Bassam and Hamzeh [9]. Hiroshi Tanaka [10] constructed a basin type solar still with internal and external reflectors. Tiwari et al. [11] used a multi wick solar still with electrical blower. Jim et al. [12] used a multiple tray tilted still. Velmurugan et al. [13] increased the exposure area of the water surface using sponges and fins in a single basin solar still; the study found that the productivity increases from 1.88 to 2.8 kg/m²/day. El-Sebaii et al. [14] attempted to improve the daily productivity of the single effect solar stills. a single-slope single-basin solar still integrated with a Shallow Solar Pond (SSP) to perform solar distillation at a relatively high temperature. Jianyin et al. [15] designed a new multi-effect solar still with enhanced condensation surface, which applies the corrugated shape structure. John [16] designed a solar water purifier. Tiris et al. [17] conducted experiments on two flat plate solar collectors integrated with a basin type solar still. Performance study on solar still with enhanced condensation was studied by Vinoth and Kasturibai [18]. Hussaini and Smith [19] studied the effect of applying vacuum inside the solar still. Recently, Gnanadason et al. [20] reported that using nanofluids in a solar still can increase its productivity. They investigated the effects of adding carbon nanotubes (CNTs) to the water inside a single basin solar still. Their results revealed that adding nanofluids increases the efficiency by 50%. Nevertheless, they have not mentioned the amount of nanofluid added to the water inside the solar still. Regarding the addition of nanofluids to the solar still, the economic viability should be considered. Some works reported that adding dyes to solar stills could improve the efficiency. For instance, Nijmeh et al. [21] concluded that adding violet dye to the water inside the solar still increases the efficiency by 29%, which is considerable. On the other hand, it is evident that nanofluids (especially CNTs) compared to dyes are more expensive, hence this may be a challenge on using nanofluids in solar stills, because in this type of use of nanofluids in solar stills the nanofluids have no flow in a closed loop so that they could be recovered.

In this context, the attempts are also made to increase the productivity of water by integrating the still basin with external condenser and using the nanoparticle sized in solar still with conventional water. The fluids with solid-sized nanoparticles suspended in them are called nanofluids. The suspended metallic or nonmetallic nanoparticles change the transport properties, heat transfer characteristics and evaporative rate of the base fluid. These nanofluids are expected to exhibit superior heat transfer properties compared with conventional water in the solar still and hence the increase in the productivity and efficiency of the solar still [22].

Section snippets

Experimental setup

In this work, two basin stills were designed, fabricated and constructed to compare the performance of the solar desalination system. One of them is a conventional type and the other is the modified basin still as shown in Figs. 1a and 1b. The conventional still has a basin area of 0.5 m² (1000 mm × 500 mm). The high-side wall depth is 450 mm and the low-side wall height is 160 mm. The still is made from galvanized iron sheets (1.5 mm thick). The whole basin surfaces are coated with black paint from

Experimental procedure

Experiments are constructed and conducted at Faculty of Engineering Kafrelsheikh University, Egypt. The experiments were carried out at the period from sunrise to sunset, during April 2013 to July 2013. The solar radiation, atmospheric temperature, basin temperature, saline water temperature, glass temperature and distilled water productivity were measured every hour. However, the accumulated productivity during the 24 h had also been measured in each test. The depth of the saline water in the

Error analysis

During the experiments, several parameters are measured in order to evaluate the system performance. The quantities needed to be measured are, the temperatures at different points of the stills (brine and glass cover temperatures), ambient temperature, total solar radiation, wind velocity and the amount of distillate. The temperatures have been measured using calibrated copper constantan type thermocouples (±1 °C) which were connected to a digital temperature indicator. Total insolation was

For the case of continuous running fan

The variation of solar radiation, atmospheric temperature, basin water temperature, and glass temperature of stills is shown in Fig. 2. It is clear that the profile of the solar radiation incident during the days of the testing has the same behavior. The solar radiation increases in the morning hours reaching its maximum values around midday and then decreases in the afternoon. Also, it can be observed from Fig. 2 that, the maximum temperature is obtained during the period from 11 am to 3 pm.

Cost evaluation

The total fixed cost of conventional still is about F = 103 $. To obtain the average value of the cost of distillate output it is assumed: n is the expected still life time, V is the variable cost, C is the total cost, where, C = F + V. Assume variable cost V equals 0.3 F per year [25], and for the expected still life 10 years, then C = 103 + 0.3 × 103 × 10 = 412 $, where the minimum average daily productivity can be estimated from the analysis of different experimental data, and it is assuming that 2.5 l/m² a

Conclusions

In this work, the effect of integrating the still basin with external condenser and using nanofluids on the performance of modified solar still was investigated experimentally under outdoors of Kafrelsheikh city (north of Egypt) climatic conditions. It was found that using a small power consumption fan, which works with photovoltaic solar panels, improves the evaporation and condensation rates by avoiding the effect of non-condensable gases and creating an amount of turbulence of the water

References (25)

A.E. Kabeel
Performance of solar still with a concave wick evaporation surface
Energy
(2009)
H.M. Ali
Experimental study on air motion effect inside the solar still on still performance
Energy Convers Manage
(1991)
F. Tabrizi et al.
Experimental study of an integrated basin solar still with a sandy heat reservoir
Desalination
(2010)
S. Abdallah et al.
Sun tracking system for productivity enhancement of solar still
Desalination
(2008)
P.K. Abdenacer et al.
Impact of temperature difference (water-solar collector) on solar-still global efficiency
Desalination
(2007)
K. Voropoulos
Solar stills coupled with solar collectors and storage tank: analytical simulation and experimental validation of energy behavior
Sol Energy
(2003)
G.N. Tiwari
Present status of solar distillation
Sol Energy
(2003)
V. Velmurugan et al.
Single basin solar still with fin for enhancing productivity
Energy Conserv Manage
(2008)
A.A. El-Sebaii et al.
Thermal performance of a single basin solar still integrated with a shallow solar pond
Energy Convers Manage
(2008)
H. Al-Hussaini et al.
Enhancing of solar still productivity using vacuum technology
Energy Convers Manage
(1995)

S. Nijmeh et al.

Experimental and theoretical study of a single basin solar still in Jordan

Int Commun Heat Mass Transfer

(2005)

Shuying Wu

Thermal energy storage behavior of Al₂O₃ – H₂O nanofluids

Thermochim Acta

(2009)

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Enhancement of modified solar still integrated with external condenser using nanofluids: An experimental approach

Highlights

Abstract

Introduction

Section snippets

Experimental setup

Experimental procedure

Error analysis

For the case of continuous running fan

Cost evaluation

Conclusions

Energy

Energy Convers Manage

Desalination

Desalination

Desalination

Sol Energy

Sol Energy

Energy Conserv Manage

Energy Convers Manage

Energy Convers Manage

Int Commun Heat Mass Transfer

Thermochim Acta