Sandbattery
Welcome to my sandbattery blog! Here is documentation from our sand battery's construction. We wanted to try to build one after seen Tampere university's and Nightpolar's example projects on news.
We are going to update while construction proseeds. This blog is meant for relatives and people interested on topic.
Why we desided to try building an sand battery?
In short. Very expencive electricity prices. I started considering self sufficent heating options more and more every time I had to pay electricity bill. First I started consider could I heat shower water with wood boiler. Soon after there was an idea to save wood in summer by using solar heat collectors.
I started looking up used wood boilers, water heaters and solar collectors. Water boiler should be big enough so we would not have to make fire every shady day. But there was a problem. Big hybrid water boilers were expencive. So I started to find cheaper alternatives. I even made prototype on our Sauna cabin. After that I desided to try to build own sandbattery which cost should only be 10% from new hybrid water heater.
prototype for heating Sauna's water. Eventually when spring advanced water started boiling and plastic melted. It was not long service but excelent test
Planning
First plan was inspired by "Solar home heating" channel. An cheaper alternative from sand battery. Insulated sand pile would be easy to build.
After planning more we desided to build under ground. Then it would be out of sight.
After long considerations we desided to build as close to shower (2 small windows) as possible. It would save on insulation and plumming costs. After project is done we could grow plants on top of battery
Construction
After planning I invited my brothers and dad to help building. We dug 1.3m deep pit and trench for drain. We built insulating cube from xps-boards and tape. I put just in case fire proof sheet at the bottom.
First we put 15cm sand. Then copper piping coil for shower and radiators. Plumming uses thermodynamic principle to minimise temperature differences on outer wall and outside. On center we keep sand as hot as possible with heating coils and by taking heat energy from edges; first cold water goes at bottom and finally to top.
On picture is shower heating coil and temperature sensors. There is still space for 2 heating coils in middle. There are 6 planned temperature sensors inside battery. They enable heat adjustment so we can be careful with legion-, freezing-, boiling- and xps melting- -hazards.
Big thanks to
university of Tampere, Inka Särestö's Bachelor's thesis, Polar Night, Solar home heating Youtube channel, Sergiy Yurko Youtube channel, my family members and neightbours who helped building