Compost Tea Bar is an installation that sought to investigate the use of compost as a free energy in response to rising energy prices and the effect fossil fuels have on the planet. . In the past home inventors have experimented with extracting heat from compost by building huge piles of compost and wrapping water filled piping around the pile to tap into the heat as it escapes the mound. The water is then used for domestic needs such as baths and washing up.
People tend be have a lack of interest in rotting compost so the installation adopted the aesthetic of a scientific burger van. We wanted to show the wonder of compost being able to heat water and used builders tea made with the heated water and served in test tubes as a further way of engaging people. We feel if people can understand how energy can be produced through waste it will open eyes and reevaluate what we currently throw away and under value.
The technique to gain the maximum heat is to fill a container in one go with equal amounts of green/brown waste with a combination of them being both soft/tough materials everything starts to decompose rapidly. Within a few days the heap of waste starts to build up significant heat – it was this that we wanted to tap into with Compost Tea Bar.
We used an old shipping crate as our compost container and installed insulation on all sides of the cube to reduce heat loss. All cracks were filled with to make the container air tight apart from holes at the bottom of the container to help the decomposing process.
We then built a simple copper heat exchanger which drov water through the hot compost from a header tank – picking up heat on its journey. The experimental set-up managed to heat water to 57 degrees Celsius, which was then topped up to boiling a kettle.