“You most certainly DO get an average of 5.38 kWh/day at Phoenix. This is simply the average amount of energy from the Sun over the whole year. This is similar in magnitude to the figures given in standard energy balance diagrams. It’s uncontroversial and correct.”
No, your reference was from a solar company. If you are correct than this solar company has made a mistake. Or the amount solar energy that hits a solar panel should be more energy per sq meter than amount that would “on average” or hitting a flat level section of ground, would be.
Or it’s a given that standard procedure used in the solar power industry would generally get more energy per year per square meter than what gotten “naturally” per square meter of the same earth surface.
“In nature” a south facing sloped piece of land [in northern hemisphere and temperate zone] receive more solar energy than a flat piece piece of land. Such a section of land could receive similar amount of energy per meter as solar panel would receive.
This is called southern exposure
“Another contributing factor to microclimate is the slope or aspect of an area. South-facing slopes in the Northern Hemisphere and north-facing slopes in the Southern Hemisphere are exposed to more direct sunlight than opposite slopes and are therefore warmer for longer.”
http://en.wikipedia.org/wiki/Microclimate
They know this in farming/gardening, they also know this in solar industry.
“The average insolation at the surface over the whole planet is about 184 W/m^2, which can also be written as 4.4 kWh/day/m^2. Some cities in the USA get more than the planetary average, others get less. Atlanta Georgia is pretty close to the average.”
You seem to have a lot faith in this number, which I do not share. I would say it is within 10 W/m^2, maybe, probably. The only reason I have this much faith in the number [to say it is within 10 W/m^2] is because I know the tropics dominates this planet and the tropics are more or less flat ocean- and oceans in general can viewed as more or less flat. I am ok with using it as approximation.
But I think it’s somewhat crazy not to have a more precise number, when one hopes to model 100 year into the future, and one is concerned about 2.4 watts, and tenths of a degree in temperature.
“If that sounds confusing, think of it this way. Suppose you have a large field, of about 10000 square meters, and use lots of panels to get all the possible energy on that field from the Sun. You can’t get more energy by mounting the panels at an angle, or using a tracking device. ”
Yes you can. It’s not in doubt.
It is more expensive to track, and so it’s mostly not considered worth it
But merely have solar panel at a correct angle will allow a solar panel to generate the most amount of energy.
There are two different factors here and you focusing on just one factor. Actually there are three factors.
A solar panel or natural surface of anything will receive/absorb more energy if more perpendicular to the sun- whether there is atmosphere or not for two reason, reflects less energy and more energy per square meter.
With an atmosphere at lower angle sunlight has pass through more atmosphere [and atmosphere may reflect more at this angle].
So, actually, possibly 4 significant aspects.
“The point is, you really are incorrect in thinking that half the energy from the sun gets absorbed or lost somehow in the atmosphere. The conventional numbers quoted by scientists for this bit of basic background information on energy from the Sun are correct.”
Ok, opinion noted.
I have not understood anything which suggests the less than 1/2 the light is in some manner prevented from reaching the surface [ground or water].
“Here it is yet again. The sun gives about 1364 W/m^2 at Earth’s distance. Spread over a globe, that works out to 341 W/m^2. Of this, you have the following:
(1) About 79 W/m^2 is scattered or reflected to space from the atmosphere.
(2) About 78 W/m^2 is absorbed in the atmosphere.
(3) About 23 W/m^2 is reflected back to space from the surface.
(4) About 161 W/m^2 is absorbed at the surface.”
It should note I find this a strange way to anything- despite how popular it may be. But I am curious would one apply this to the Moon?
So, you don’t have 1 and 2. and are left to resolve 3 and 4.
