Novel cooling system for free-standing photovoltaic panels

ABSTRACT

Although photovoltaic (PV) technologies enjoy tremendous benefits and hold the huge potential to lower building overall energy consumption, there is a major drawback. PV efficiency is extremely sensitive to heat and significantly reduced by increasing setting temperature and solar irradiance; thereby, thermal management in PV collectors plays a significant role in generating electrical energy. Using oscillating heat pipes attached to the rear side of PV panels is considered a novel and useful approach to dissipating heat. In this study, a novel cooling system that consists of a newly designed spiral oscillating heat pipe is introduced, while DI water and 0.2 g/l graphene are used as working fluid and PV panels are located at tilt angles of 30° and 60°. The OHP efficiency is higher at 60°; however, the efficiency of PV is maximized at 30° since the panel is exposed to maximum solar irradiance. The research demonstrates that the cooling method proves highly effective, especially in the hottest time of the day and the power output improves considerably from 38 W to more than 42 W at 30°, while the value is about 39.7 W when water is used as a coolant.

KEYWORDS:

• Graphene oxide
• heat transfer
• nanofluid
• oscillating heat pipe
• photovoltaic system

Nomenclature

A	=	collector aperture area (m2)
${\mathit{C}}_{\mathit{p}}$	=	heat capacity of flowing medium (J/kg k)
G	=	incident solar radiation (W/m2)
I	=	electric current(A)
$\dot{\mathit{m}}$	=	mass flow rate
Q	=	heating power (W)
P	=	power (W)
T	=	temperature (°C)
R	=	thermal resistance (°C W−1)
V	=	voltage (V)
$\mathit{\eta }$	=	efficiency (%)
Acronyms	=
OHP	=	oscillating heat pipe
PV	=	photovoltaic
Subscripts	=
c	=	condenser
e	=	evaporator
in	=	input
mp	=	maximum power point
oc	=	open-circuit
out	=	output
sc	=	short-circuit

Disclosure statement

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