EcoRenovator - View Single Post - When solar PV or solar heating for your next renovation

Exeric · 11-30-13, 07:40 PM

I think all of us have our favorite implementations of green technology. I plead guilty as charged. I think some of us aren't as conscious of our biases as we should be, especially before influencing people new to this forum. Every climate and home site has advantages that favor one technology over another. One size does not fit all.

One thing I'm beginning to realize is just how important the different home site characteristics are when deciding between solar PV or solar heating. Climate is the controlling factor for both with house orientation to the sun coming in a close second. When I say that I'm considering both the ability to utilize the sun and also the cost and complexity to do that. Here's a map of the concentrating solar insulation values for the whole year in the USA:

First thing I want to point out is that you should always use concentrating solar energy instead of PV solar energy to estimate how your site is going to do if your thinking of solar thermal. Concentrating solar energy is based on heating effect so it is based more on infrared solar energy, whether it is a parabolic mirror or a simple roof or solar heating panel collecting the energy.

Second, you actually can't use that map I just pointed to if you are trying to figure out if your site is good for solar thermal. That map is the Average solar heating effect. You need the map that includes the shortest and coldest days only. Here is the map you need: :

Some areas just are not going to work out very well for solar thermal and should probably be biased toward PV electrical. For instance I grew up in the central valley in California. It regularly hits 110F at least once a summer. You would think this area would be ideal for solar thermal. Also it never really gets below 25F and maintains an average high of 53F in late December, which is the same as where I live now, outside of the central valley. However as you can see the central valley is colored dark, dark, dark. That's because it is socked in with fog for three months each winter. There are microclimates all over California where this will occur. Fog, and most forms of precipitation, seems to be good at absorbing the infrared region of light. That's why areas around large bodies of water tend to be more moderate in temperature. Oceans absorb heat energy and release some of it when it gets colder.

Another comment coming.

11-30-13, 07:40 PM	#1
Exeric Apprentice EcoRenovator Join Date: Aug 2012 Location: California Posts: 274 Thanks: 19 Thanked 37 Times in 28 Posts	Solar PV or solar thermal for heating your home? I think all of us have our favorite implementations of green technology. I plead guilty as charged. I think some of us aren't as conscious of our biases as we should be, especially before influencing people new to this forum. Every climate and home site has advantages that favor one technology over another. One size does not fit all. One thing I'm beginning to realize is just how important the different home site characteristics are when deciding between solar PV or solar heating. Climate is the controlling factor for both with house orientation to the sun coming in a close second. When I say that I'm considering both the ability to utilize the sun and also the cost and complexity to do that. Here's a map of the concentrating solar insulation values for the whole year in the USA: First thing I want to point out is that you should always use concentrating solar energy instead of PV solar energy to estimate how your site is going to do if your thinking of solar thermal. Concentrating solar energy is based on heating effect so it is based more on infrared solar energy, whether it is a parabolic mirror or a simple roof or solar heating panel collecting the energy. Second, you actually can't use that map I just pointed to if you are trying to figure out if your site is good for solar thermal. That map is the Average solar heating effect. You need the map that includes the shortest and coldest days only. Here is the map you need: : Some areas just are not going to work out very well for solar thermal and should probably be biased toward PV electrical. For instance I grew up in the central valley in California. It regularly hits 110F at least once a summer. You would think this area would be ideal for solar thermal. Also it never really gets below 25F and maintains an average high of 53F in late December, which is the same as where I live now, outside of the central valley. However as you can see the central valley is colored dark, dark, dark. That's because it is socked in with fog for three months each winter. There are microclimates all over California where this will occur. Fog, and most forms of precipitation, seems to be good at absorbing the infrared region of light. That's why areas around large bodies of water tend to be more moderate in temperature. Oceans absorb heat energy and release some of it when it gets colder. Another comment coming. Last edited by Daox; 12-02-13 at 11:00 AM..