Development of a solar device for jute filling based humidification dehumidification desalination

ABSTRACT

It is predicted that the ground water sources which are currently termed as sustainable will also begin to deteriorate, and this may lead to the degradation of the cropland and may severely affect food production, smooth colonial expansion and also damage the balance of ecosystem. Since 2011, much of the interest has been laid upon the concepts of Ecohydrology, which dwells upon the interconnectivity of ecosystem and hydrology. This study emphasises on the recycling of waste water and desalination of sea water. Among various desalination techniques, humidification–dehumidification (HDH) technique, using solar energy as the heat source for evaporation of salt water, has gathered attention in recent years. A conventional solar reflector HDH desalination plant requires a humidifier, where saline water is fed and made to evaporate in running air, when drizzled through nozzles and passed through the jute surface, which will be further reduced due to a fan which will be installed at the end of a humidifier region. Therefore, there will be enhancement in vapour formation and then sent to a dehumidifier where pure water is separated from moist air through condensation. The proposed unit in which latent heat can be recovered, which may yield 20 L/day on floor area of 2 m² and adopting jute as filling in humidifier. The latent heat that is extracted from the moist air may be further utilised in the preheating of the saline water. Here, a prediction model was developed over data collected for 25 days and net gain obtained from the experimentation will be used to calculate gained output ratio. A preliminary parametric study to explore the technical feasibility of the HDH reveals that a fixed bed column filled with EDTA provides a longer working duration to assure the overall system’s performance and to remove surplus salt.

Keywords:

• Solar
• desalination
• humidification-dehumidification

Notations

S	=	solar energy absorbed by the glass cover, W/m2
Ib	=	beam solar radiation, W/m2
Rb	=	ratio of beam radiation on tilted surface to that on horizontal surface
τ	=	transmissivity
α	=	absorptivity
Id	=	diffuse solar radiation, W/m2
β	=	tilt angle of the glass cover
ρg	=	ground reflectance
Ac	=	surface area of collector, m2
UTotal	=	overall heat transfer coefficient of glass cover and convective environment on either side of it, W/m2K
Tm	=	mean plate temp, °C
Ta	=	ambient air temp, °C
Fr	=	heat removal factor
Ti	=	temperature of incoming saline water in the humidifier, °C
mw1	=	mass flow rate of incoming saline water, kg/s
$c_{p_w}$	=	specific heat of water, J/kg°C
To	=	temperature of outgoing saline water from the humidifier, °C
$\underset{\mathrm{a}}{\overset{\cdot }{\mathrm{m}}}$	=	mass flow rate of air in the humidifier, kg/s
$h_{a_i}$	=	enthalpy of air at the inlet of humidifier, J/kg
$h_{a_0}$	=	enthalpy of air at the exit of humidifier, J/kg
$h_{{\mathit{a}}_{\mathit{di}}}$	=	enthalpy of saturated air at the inlet of dehumidifier, J/kg
$h_{{\mathit{a}}_{\mathit{do}}}$	=	enthalpy of dehumidified air at the exit of dehumidifier, J/kg
$m_{cw}^{\cdot }=m_{\mathit{w}1}$	=	as incoming saline water is used as cooling media in dehumidifier, so as to retain the latent heat of the condensed fluid, kg/s
$T_{{\mathit{w}}_{\mathit{ci}}}$	=	temperature of cooling water before entering the dehumidifier, °C
$T_{{\mathit{w}}_{\mathit{co}}}$	=	temperature of cooling water exiting the dehumidifier, °C
$m_{dw}^{\cdot }$	=	mass flow rate of distillate, kg/s
$T_{w_d}$	=	temperature of distillate, °C
${\mathrm{T}}_{{\mathit{a}}_{\mathit{di}}}$	=	temperature of incoming humid air in dehumidifier, °C
${\mathrm{T}}_{{\mathrm{a}}_{\mathit{do}}}$	=	temperature of outgoing humid air in dehumidifier, °C
${\mathrm{U}}_{\mathrm{d}}$	=	overall heat transfer coefficient, W/m2°C
${\mathrm{A}}_{\mathrm{d}}$	=	surface area of dehumidifier tubes, m2
$\mathrm{k}$	=	mass transfer coefficient
$\mathrm{a}$	=	surface area of the humidifier, m2
$V_h$	=	volume of humidifier, m3
$h_a$	=	enthalpy of air at any instant, J/kg
$C_{p_a}$	=	heat capacity of air, 1.009 kJ/kg°C
$C_{p_v}$	=	heat capacity of vapour, 1.88 kJ/kg°C
$W_a$	=	humidity ratio
$h_{\mathit{fg}}$	=	latent heat of evaporation and condensation, J/kg
$p_{\mathit{db}}$	=	pressure of air at dry bulb temperature, bar
$p_{\mathit{atm}}$	=	atmospheric pressure, bar
$\mathit{\phi }$	=	relative humidity
$p_{\mathit{sat}}$	=	saturation pressure of air at given temperature, bar
$W_{\mathit{adi}}$	=	humidity ratio at dehumidifier inlet, kg moisture/kg of air
$W_{\mathit{ado}}$	=	humidity ratio at dehumidifier exit, kg moisture/kg of air
${\rho }_a$	=	density of air, kg/m3
${\eta }_{\mathit{fan}}$	=	efficiency of fan
$H_o$	=	average clear sky radiation, MJ/m2
$\mathrm{a},\mathrm{b}$	=	empirical constants
$\bar{\mathrm{n}}$	=	generalised average daily hours of bright sunshine, on a broader scale
$\bar{N}$	=	average of maximum possible daily hours of bright sunshine

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The authors confirm that the data supporting the findings of this study are available within the article or its supplementary materials.

Additional information

Notes on contributors

Akbar Ali

AkbarAli is currently working as Assistant Professor in the Department of Mechanical Engineering, Medi-Caps University. With academic experience of over 12+ years, he has been pursuing his research in solar desalination pertaining to the field of Thermal Engineering, in which he had specialized and completed his Masters in 2012. Prof. Ali completed his graduation in BE Mechanical Engineering in 2007 from Jawaharlal Institute of Technology, Borawan. He has authored a textbook on Heat Transfer, and published and presented many research papers.

Neelesh Kumar Sahu

Neelesh KumarSahu is currently working as Associate Professor in Mechanical Engineering Department at Medi-Caps University, Indore (MP), India. He has done his Ph.D. in Mechanical Engineering from Visvesvaraya National Institute of Technology (VNIT) Nagpur in 2018, MTech in Mechanical Engineering from PDPM Indian Institute of Information Technology Design and Manufacturing (IIITDM) Jabalpur in 2012 and B.E. in Mechanical Engineering from R.G.P.V. Bhopal in 2007. His areas of research are Machining, Optimization, Non-conventional Machining, Condition Monitoring and Nanofluids. He has published 14 papers in SCI/Scopus/Web of Science Journals. He has presented his research work on international platforms such as ASME, Boston, USA (2015) and BITS Dubai, UAE (2017). He was associated with various research projects like “Nanofluids as coolant”; “Material deposition in EDM process”; “Cutting tool condition monitoring using virtual instrumentation”; “Machining of super alloys” and many more. He has also worked in cutting tool industry, i.e. YG-1 Industries India Pvt. Ltd. and automobile industries namely Fleetgaurd Filters Pvt. Ltd. He has 5 years of academic experience including working in Shri Ramdeobaba College of Engineering and Management, Nagpur, NIRF Ranking 64 in 2017. He was deported in 2008 for hands-on training on cutting tool manufacturing such as End mills, Taps, Drills and special tools in YG-1 Co. Ltd., Incheon, South Korea and New Century Tool Corporation, Qingdao, China. He has various MTech and PhD projects in the field of machining.

Mohd Irfan Khan

Mohd IrfanKhan is currently working as Assistant Professor in Mechanical Engineering Department at Medi-Caps University, Indore (MP), India. He has done his M.E. in Mechanical Engineering from Institute of Engineering and Technology (IET) DAVV Indore in 2011 and B.E. in Mechanical Engineering from Institute of Engineering and Technology (IET) DAVV Indore in 2009. His areas of research are machine design, industrial engineering and computational fluid dynamics. He has published five papers in journals and conferences. He has presented his research work on national platforms such as BITS Hyderabad and SVNIT Surat. He was associated with various researches like “Design and Analysis of an Automotive Aerodynamic Device by Using Computational Fluid Dynamics”; “Comparative Analysis of Use of an Aerodynamic Device in LMV by Using Computational Fluid Dynamics”; “A comprehensive review on design, optimization and vibrational analysis of a helical spring”; “Design and CFD Analysis of the Waste Chill Recovery Heat Exchanger”; “Application/Implementation of Quality Function Deployment: A Case Study in Two Wheeler Segment” and many more. He has 9+ years of academic experience including working in “Truba College of Engineering and Technology” and “Medi-Caps University”. He was awarded best faculty award by SRIJAN in the year 2014–2015.

Prakhar Sharma

PrakharSharma completed his graduation in Mechanical Engineering from Medi-Caps Institute of Technology and Management in 2019. At this juncture of career, his educational qualification, as well as rigorous training in all aspects of mechanical engineering, has developed a keen desire in him to pursue his career in the field of Thermal and Fluid Science.

Vipul Raj Singh

Vipul RajSingh is presently pursuing MTech in Thermal Engineering from Medi-Caps University, Indore. He has keen interest in the field of thermal energy as well as in the field of utilization of solar energy.