A very simple way to eliminate boilers, heating bills and buring fossil fuels in buildings would be to store sufficient heat energy during the summer months, and utilising this throughout the winter.
This basic premise has been of interest to us for many years and we are now hoping to apply the ‘inter-seasonal thermal store’ on a project here in the UK.
The underground thermal storage tank is not a new idea, but a number of specialist companies in northern europe have been installing and testing these systems in recent years.
A solar collector array feeds a super-insulated underground water storage tank, which is sized to provide the full winter heating energy of the development.
Water is stored at (up to) 100C at the end of the summer, and then depletes slowly as energy is withdrawn for heating and hot water, with a known allowance for standing losses from the system.
For our project (28 unit housing development) the new build dwellings will be constructed to a high thermal specification such that heat losses are minimised, keeping the size and cost of the solar collector array and the storage tank to a minimum.
In order to avoid losing valuable open space above the tank, a space frame structure is installed within the tank in order for a deep insulation layer to be installed on top, with sufficient strength to allow the ground to be used for an array of activities and uses.
Here are some images of the Hocosto inter-seasonal store being installed: