Comprehensive analysis of salt gradient trapezoidal solar ponds with coal cinder and East-West reflector: experimental and numerical study

ABSTRACT

In sustainable energy systems, the salt gradient solar pond has emerged as an eco-friendly approach to thermal energy storage. This study investigates the benefit of an East-West (EW) reflector and coal cinder additive (CC) to improve the exergy efficiency in the inner zones of a salt gradient solar trapezoidal pond. Additionally, it presents a temperature distribution model for solar ponds. In this study, we designed, constructed, and analyzed salt gradient trapezoidal solar ponds, evaluating them from an exergy perspective and comparing them to conventional trapezoidal systems. Our findings reveal that the implementation of a double glass cover led to a substantial increase in the average temperature of the heat storage zone, registering a 10.12% boost for the conventional trapezoidal system and a 12.31% enhancement for the trapezoidal system with East-West reflectors. Moreover, the average energy and exergy efficiencies of the lower convection zone for the conventional trapezoidal systems were determined to be 9.2% and 0.5%, respectively, while for the trapezoidal system with coal cinder additives and east-west reflectors, these values were notably higher, at 15.4%, and 0.94%, respectively.

KEYWORDS:

• Coal cinder
• East-West reflector
• solar pond
• energy efficiency
• exergy efficiency

Nomenclature

$A$	=	Upper layer surface area(m2)
$A_S$	=	Sunny area(m2)
$A_S$	=	Shaded area(m2)
$C$	=	Specific heat capacity(kJ/kg-K)
$h$	=	Portion of solar radiation conducted (W/m2)
$I$	=	Incident solar radiation(W/m2)
$R$	=	Coefficient of reflection
$Q_s$	=	Solar radiation reaching each zone(W/m2)
$Q_c$	=	Heat transfer through conduction(W/m2)
$T$	=	Temperature (°C)
t	=	Time (minutes)
$x$	=	Pond layer thickness (mm)
Abbreviations	=
bp	=	bare pond
cin	=	cinder
ref	=	reflector
sol	=	solution
Greek symbols	=
${\theta }_i$	=	Angle of incidence
${\theta }_{rf}$	=	Angle of refraction
$\delta$	=	Declination angle
$\rho$	=	Density (kg/m3)
$\eta$	=	Efficiency
$\alpha$	=	Elevation angle
θh	=	Hour angle
$\theta$	=	Reflector tilt angle
$\phi$	=	Latitude

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplemental data

Supplemental data for this article can be accessed online at https://doi.org/10.1080/15567036.2023.2268568.

Additional information

Notes on contributors

Vinoth Kumar Jayakumar

Vinoth Kumar Jayakumar Assistant Professor, Bannari Amman Institute of Technology, Sathyamangalam Vinoth Kumar J is an Assistant Professor at Bannari Amman Institute of Technology in Sathyamangalam, specializing in the field of solar energy. His research and academic pursuits have been primarily focused on harnessing the potential of solar energy.

Amarkarthik Arunachalam

Amarkarthik Arunachalam Professor, Bannari Amman Institute of Technology, SathyamangalamAmarkarthik Arunachalam is a Professor at Bannari Amman Institute of Technology in Sathyamangalam, specializing in the field of renewable energy. His research and academic pursuits have been primarily focused on harnessing the potential of unconventional energy sources.