Heat Transfer: External Flow.
Book: Fundamental Heat and mass Transfer 7th Edition
Problem #7.19: Concentration of sunlight onto photovoltaic cells is desiredsince the concentrating mirrors and lenses are less expensive thanthe photovoltaic material. Consider the solar photovoltaic cell of Problem 7.18. A 100 mm x 100 mm photovoltaiccell is irradiated with concentrated solar energy. Since theconcentrating lens is glass, it absorbs 10% of the irradiationinstead of the top surface of the solar cell, as in Problem 7:18.The remaining irradiation is reflected from the system (7%) or isabsorbed in the silicon semiconductor material of the photovoltaiccell (83%). The photovoltaic cell is cooled by air directedparallel to its top and bottom surfaces. The air temperature andvelocity are 25 degrees C and 5 m/s, respectively, and the bottomsurface is coated with a high emissivity paint,εb=0.95
(A) - Determine the electric power produced by the photovoltaiccell and the silicon temperature for a square concentrating lenswith Llens = 400 mm, which focuses the irradiationfalling on the lens to the smaller area of the photovoltaic cell.Assume the concentrating lens temperature is 25 degrees C and doesnot interfere with boundary layer development over the photovoltaiccell's top surface. The top and bottom boundary layers areboth tripped to turbulent conditions at the leading edge of thephotovoltaic material.
(B)- Determine the electric power output of the photovoltaic cell and the silicon temperature over the range 100mm ≤ Llens ≤ 600 mm.
Attachment:- Problem 7.18.pdf