Central SDH system

The Central solar district heating system with ground buried tank thermal energy storage is composed of a large collector field feeding into a tank thermal energy storage situated at the main heating central of the district heating system, see graph. When the solar plant produces heat when there is no heat demand, it is fed into the storage. Depending on the temperature in the storage and the temperature coming from the collectors the solar heat can either be fed in at the top or in the middle of the storage. In the time periods when the solar plant produces heat and heat demand occurs at the same time a direct pre-heating is possible, meaning the solar heat feeds directly into the main heating station and not by way of the storage. Also a simultaneous charging (in teh middle) and discharging (from the top) of the storage is possible if e.g. the solar collectors deliver only low temperature heat due to bad weather conditions but at the same time the heat demand in the distribution network can be covered from the top part of the storage. An auxiliary heat source supplements the solar heating plant in order to cover the total heat demand.