Today is Earth Day which seemed like a fitting occasion to begin monitoring the performance of the Greeny Flat experiment. So for Earth Day next year we’ll host a get-together on site to present the results which will hopefully prove that the Greeny Flat has made more energy that it has used over a full year while providing a comfortable and healthy indoor environment and only using a small amount of town water.
We now have the solar power system installed and running and we have a wonderful gadget called a Wattson meter sitting next to the kitchen which shows us how much power we’re making, how much we’re using, and the net amount of power going to or coming from the Grid at any time. It’s fascinating to see how things change at different times of the day and when we turn different appliances on or off. We already knew that it would be the things that use electricity to create heat that would use the most power but it’s amazing to see just how much the electric kettle and the stove consume when they’re on. We’re already figuring out ways to use more power during the day (when the sun is shining and we’re generating electricity) rather than at night. This won’t affect the overall balance of power over the year but it will affect our electricity bills because we are paying 26 cents for the power we take from the grid but only getting 8 cents for the power we export to the grid. So the more we can use our own solar power the lower our bills will be.
The main thing we’re hoping to prove is that the Greeny Flat can be energy positive over a year. In other words it should make more power than it uses. In order to be able to prove this we have two electricity meters installed (see photo below). The one one the left labeled “Import” measures how much power we are drawing from the grid and the one on the right marked “Export” measures how much power we put into the grid from our solar system. As you can see, at the beginning of our year of monitoring the Import meter is reading 31kWh and the Export meter is reading 79kWh. So we’re off to a good start since we’ve already made more than twice as much power as we’ve used. On Earth Day next year we’ll read both meters again and subtract these initial readings in order to calculate how much power we’ve used and how much we’ve made.
We also have two water meters, one to measure how much rainwater we use and one to measure how much town water we use. Our hope is that, by the end of the year we will have used more rainwater than town water. Of course this will depend entirely on how much rain falls over the next year but once again we’re off to a good start having used only 725 litres of town water and 4307 litres of tank water (see photos below).
The other main thing that we want to prove is that the Greeny Flat can stay comfortable even though it doesn’t have a heating or cooling system installed. In order to do this we have installed a data recording weather station that measures and records the indoor and outdoor temperature and humidity as well as wind speed and direction, light levels, barometric pressure, and rainfall. We will be able to download all of this data to computer and display it in graph form. It will be fascinating to compare the weather data with comfort levels and power production and consumption. It’s also pretty nice to have this display that shows the current indoor and outdoor conditions as well as this amazing solar powered outdoor unit that looks like a mini spaceship.
So that’s all the monitoring equipment we’ve installed so far. We’re still waiting for the solar hot water system to arrive and I’ll be curious to see how we can monitor what it’s doing. Meanwhile we’ve got plenty of new toys to play with as well as plenty more work to do to actually finish the Greeny Flat. Who know’s, by Earth Day next year we might have it done.