Storing heat in the form of sensible energy using water is the easiest technology in low tech form. Our invention consists of a simple storage construction for buffering seasonal thermal heat (STES).

The buffer receives heat during summer, and returns this heat during wintertime to conventional heating- and hot water systems.  As it is simple, it is also a very understandable product for installers around the world.

HoCoSto buffers solar energy in an underground storage during summer in the form of sensible heat for use in winter. It behaves like a huge solar boiler, and most of the standard controllers can handle multiple boilers in a system. Therefore, no additional equipment is needed to integrate in a standard solar installation.

The storage desires not that much space and can be easily placed under a parking place, playground or lawn without losing the functionality of this area. Charging the heat storage can be done in many ways as there are multiple technologies to generate heat. Solar heat pipes are the most likely source but one can also use waste heat from air conditioning systems, or process heat from factories.

The STES is in a closed circuit with the generating source, in other words: the water which is in the unit, stays in. The construction of the storage will be subsurface and is able to deal with wheel pressures of 5 tons per wheel. Therefore, it can be installed in almost every area with no loss of space.

The HoCoSto storage is modular and can be assembled on spot. An earthmoving company will take care of the installation of the HoCoSto storage. This easies the logistics around the project and makes it possible to do the installation start-to-finish within one week!

Once installed, the HoCoSto STES unit will minimize or eliminate the monthly costs for heating. Depending on its scale, one can become totally self-sufficient and decide to go ‘off-grid’.