Solar Energy Storage

Earth Energy Bank
The Zero Carbon Solution features an inter-seasonal heat store known as the Earth Energy Bank (EEB), which preserves the heat collected in the summer for use during the winter months.
Earth Energy Bank

The Energy Energy Bank (EEB) is a patented energy storage method. Heated fluid is pumped from the roof through a series of pipes underneath the house, warming the surrounding earth.
Under every house there is a substantial mass of earth. This earth has a large thermal capacity and a low thermal conductivity, making it an ideal medium for heat storage. Furthermore, it’s there already, we do not have to provide it.

Making use of it as a heat store is delightfully simple. We drill a matrix of holes 1.5 meters deep and 1.5 meters apart into which we insert some pipes which carry the solar energy from the roof into the ground.

The holes are drilled using a simple auger similar to that used for fence posts, but which go deeper into the ground. The polyethylene pipes are electro- welded into pressure tested sub-assemblies off-site and delivered to site, ready to be dropped into the bore holes.

The boreholes are then back filled with a porridge like mineral, which provides good thermal contact between the pipes and the earth. Finally the completed assembly is covered with sand and a layer of insulation placed on top.

During the summer each panel delivers 245 watts peak of electricity and 650 watts peak of thermal energy. The thermal energy goes into the ground and the electrical energy is used to heat the hot water. When that is up to temperature, any unused power is converted into heat and joins the thermal output going into the Earth Energy Bank. Thus the heat pump can remain switched off for most of the summer.
The Earth Energy Bank is simple, quick to install and inexpensive. It requires no additional land to be excavated, no expensive deep boring equipment to be used. It is contained entirely within the building footprint, making it ideal for use in housing estates.