Photo voltaic cell Vs. solar heating panel

AI Thread Summary
The discussion compares the efficiency of photovoltaic cells and solar heating panels when exposed to a 150W bulb. The user is uncertain whether to measure the exposed surface area of the pipes or the entire panel area for the solar heating system. Suggestions include focusing on the total installation area rather than just the exposed pipe surface. Concerns are raised about using a tungsten bulb as a model for sunlight, as it lacks essential wavelengths. The user also questions what independent variable to use, considering the different panel types.
oprfot
Messages
2
Reaction score
0

Homework Statement



i've been asked to compare the efficiency of a photo voltaic cell and a solar heating cell (an array of pipes). both will be exposed to a 150W bulb for an equal amount of time.

Homework Equations



for photo cell: P=IV

for heating panel: P=fcT f=flow rate c=specific heat capacity T=change in temp


The Attempt at a Solution



im trying to say that both will have the same surface area exposed to the light, i was just wondering what measurement to use for the pipes: the surface area of the pipes that is exposed, or the area of the whole panel??


any other suggestions would be welcome :D
 
Physics news on Phys.org
I wouldn't worry about the actual surface area of the pipe. You are comparing a practical installation so the only consideration is the total floor (or roof!) area available for installation.

Using a tugsten light bulb isn't a good model for the sun, it lacks the shorter wavelength blue and UV light that the solar panel is sensitive to.
Can't you put both outside at the same time pointing in the same direction?
That would also allow you to compare their relative efficency at best - sun pointing directly at them, vs worst - sun on horizon.
 
yeah, i guess youre right, if I am comparing the panels i should just use the area.

we've been told to use a lightbulb, i know the actual sun would deliver a more useful result, but the bulb is what we're given.

now that I am thinking about it, I am not quite sure what to use as the independent variable. would the different panels be enough?
 
Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
Thread 'Voltmeter readings for this circuit with switches'
TL;DR Summary: I would like to know the voltmeter readings on the two resistors separately in the picture in the following cases , When one of the keys is closed When both of them are opened (Knowing that the battery has negligible internal resistance) My thoughts for the first case , one of them must be 12 volt while the other is 0 The second case we'll I think both voltmeter readings should be 12 volt since they are both parallel to the battery and they involve the key within what the...
Back
Top