Rainwater harvesting for dome
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| Rainwater harvester | Rainwater into tank |
It's taken a while, but we are finally getting water in the big tank in the dome. The first photo above show the rainwater harvester I built out of ABS drain pipe: it sits under the outlet of the eavestrough of the big roof surface. Water builds up pressure in the pipe then exits at the bottom and flows through a poly pipe to the tank in the dome. If I've got it shut off in the dome - like the tank's full - then water builds up in pipe, overflows and goes down the drain that was in place before I built the harvester. This contraption is temporary - I only propose to use it until the tank in the dome is full and then take it down.
The second photo shows water flowing out the pipe and into the tank. It doesn't look like all that much but with light rain coming down I measured it at around 11 litres per minute which isn't bad for free water. I believe that tank holds around 3000 litres so at that rate it would take 4-1/2 hours to fill up but of course that depends on how hard it rains. In fact the light rain tapered off after a couple of hours and then stopped, at which point the tank was a little over half full.
Once the tank is full it will help to moderate the temperature in the dome both summer and winter. In the summer on warm days it will absorb heat and thus help keep the dome from overheating. At night the warmed up tank will release heat helping to keep the evening temperature up. In winter there is no danger of overheating but on sunny days the tank will absorb heat and then release it at night: on particularly cold winter nights it will help keep the inside of the dome above freezing.