08-24-2013, 04:58 PM
I put solar PV panels on my roof which is sloped about 15 degrees to the SSE. I'm in Eden Roc. I have convinced myself that a slight slope to the south, but otherwise nearly flat, is acceptable and may be as good as anything. This is because we have a lot of cloudy weather here in Puna. When it is cloudy the sun is essentially coming from directly overhead. A slight slope to the south seems like the best compromise.
I definitely concur about the solar hot water panels. I don't see any problem with sticking them up there next to the solar PV panels. Properly sized you will rarely need the back-up heater. Grid tied houses always use electric back-up because the installation is simpler and less expensive. When my brother got grid tied solar PV he also got solar hot water. They replaced his gas water heater with electric. His power bill is still the minimum because the back-up almost never kicks on. He lives in leeward Oahu though so it is very sunny and hot there.
I have often showered in the hot water from 150' of garden hose left out in the sun. Short shower but plenty hot.
I definitely concur about the solar hot water panels. I don't see any problem with sticking them up there next to the solar PV panels. Properly sized you will rarely need the back-up heater. Grid tied houses always use electric back-up because the installation is simpler and less expensive. When my brother got grid tied solar PV he also got solar hot water. They replaced his gas water heater with electric. His power bill is still the minimum because the back-up almost never kicks on. He lives in leeward Oahu though so it is very sunny and hot there.
I have often showered in the hot water from 150' of garden hose left out in the sun. Short shower but plenty hot.