PV Gap

Katherine Said:

Why is a long, winding pipe used for the water flow inside the solar panel?

We Answered:

The long pipe is to get maximum surface area exposed to the hot air inside the solar panel.

It sounds like the problem given to you assumes that the water stays in the solar panel, and all the energy absobed by the panel goes into the water. In that case, you need to look up the concept of "specific heat", which for water, is 1 calorie per gram degree Celsius. For example, if you have 1 gram of water, and put in 5 calories of energy, the temperature goes up by 5 degrees C. Or if you had 50 grams of water, and put in 5 calories, the temperatrue goes up by 0.1 degree C. And so, forth, it's linear.

If the water is flowing through the panel, then calculating the exit temperature is a calculus problem, the kind given in the first year of college engineering.

Peter Said:

why dont people use solar panels, water ect for their electricity?

We Answered:

Right now it is prohibitively expensive. The upfront cost of the solar panels is more expensive than the money they would save for most people.
It would cost most houses at least $20k in solar panels and other equipment to generate the kind of electricity they would need, and most people just don't have that kind of money, and while there are some government rebate programs to offset some of the costs, they only cover a fraction of the total costs.
When solar panels start getting cheaper, we will see more and more of this.

Erik Said:

I need expertise opinion on solar hot water panels?

We Answered:

South is not Solar south . There is a tool you can use to determine solar south .Because the Earth is tilted on its axis.