Active solar features
Active solar systems use equipment to trap additional solar energy, for example a solar electric system to provide free electricity, or a solar hot water system to provide free hot water.
Dollar for dollar, solar water panels convert much more of the sunlight into useful energy than solar electric panels (PV panels), so the payback is faster. On our limited budget, we chose solar hot water collectors over solar electric panels for that reason. We considered wind energy too, but there are restrictions on our land which prevent us from installing a wind generator. But that is another source of renewable energy worth considering.
- We chose evacuated tube solar water collectors. These are less affected by cold winter temperatures, and work better in marginal conditions such as hazy sunshine, compared with the more traditional flat panel collectors. But remember that the technology is changing all the time, so if you are thinking of buying a solar water system, discuss the options with your suppliers to see what is best for you.
- We sized our solar hot water system fairly large. Our system generates enough hot water for all our needs, but it can also provide some space heating too, by contributing to the radiant heating system in the concrete floor. This maximizes our benefits from the thermal mass that the concrete offers. This is most effective in spring and fall when modest heating is required, but even in winter it can contribute. On a sunny summer day, the system can heat 160 US gallons of water from cold up to about 170 degF (about 76 degC). In winter, it can reach about 115 degF in a day, which is more than hot enough for a shower or bath.
- We plan to add solar electric panels. This system will then tie into the grid, so that when we generate more electricity than we need, we will sell the surplus power back to the grid. This will offset the energy we draw from the grid when there is not enough solar power. We will also have our own battery bank so that in the event of a grid power outage, we can run essential equipment such as the refrigerator, well pump and radiant heating system until power is restored, without the need for a generator.
- We considered equipment placement. Active solar systems need some space for the equipment, such as a hot water storage tank for domestic hot water and radiant heating, or a battery bank and inverter for solar electric systems. We put ours in the basement. If you don’t plan to have a basement, make sure there is an area set aside.
Our top tip: If you put panels on the roof, make sure that they won’t spend the winter covered with snow. Either place them at an angle which prevents snow collecting, or make sure you have a safe method to sweep the snow off. With hot water panels, it may pay to mount them at a steep angle which catches most sunlight in winter, and less in summer, when less hot water is needed.
Our supplier: We used ReVision Energy, a Maine-
More info:
More information on Apricus evacuated tube solar collectors:
Apricus evacuated tube solar collectors on the south-