MATHEMATICAL MODEL OF A HYBRID SOLAR PANEL

Robert Collins and Ernesto Gutierrez-Miravete

Rensselaer at Hartford

Hybrid Solar Panel

• Uses PV cell to convert a fraction of the solar irradiance into electricity.

• Uses heat exchanger principles to store most of the solar irradiance NOT converted into electricity as useful thermal energy inside a working fluid.

• The use of the heat exchanger reduces heating of the PV cell and increases its conversion efficiency.

Hybrid Solar Panel Schematic

Steady 2D Turbulent Flow of a Non-Isothermal Newtonian Fluid:

Governing Equations∂vx/∂x + ∂vy/∂y = 0

v · v∇ x = − ∂p/∂x + µ∇2 vx + ρgx

v · v∇ y = − ∂p/∂y + µ∇2 vy + ρgy

k-ε Turbulence Model

ρ Cp v · T = k∇ ∇2 T

Boundary Conditions

Model Geometry and Input

Material Property Value Reference

PV Cell ρ 2329 Siliconk 130

700ε .60 [11]

Thermal Paste ρ 3500 [12]k 2.87

.7Copper ρ 8700 Copper

k 400385

Water ρ 997.1 Water @ 25°Ck .611

= 4.184μ 902 x 10-6

Finite Element Model Mesh

Computed Velocity Field

Computed Temperature and Heat Flux Fields

Hybrid Panel Overall Efficiency

Conclusions• The greatest overall PV/T module efficiency of 85.7%

occurs with the labyrinth arrangement or the arrangement with 27 top and 27 bottom fins that are ¾ the height of the flow path. This is an approximate 5.7% increase in efficiency over the arrangement with no fins.

• When connected as an array, three modules linked in a head to tail arrangement, heat the water by 16.5 degrees Celsius and collect energy from the environment in the form of usable electrical and thermal energy.