"Combined storage" system
- Combined buffer storage system with integrated hot water storage tank and
external additional heating system
The so called "combined storage" system is based on the simple storage system with additional heating system described above, however some features have been added and others have been significantly improved. So, it consists of a combination of a buffer storage system with integrated hot water storage tank and external additional heating system. Combined storage systems are being frequently used for the support of the main heating system. In contrast to the simple storage system, the heat exchanger of the combined storage system is not surrounded by cold water but by water that comes from the heating system. For this reason calcifications can only occur at the inner wall of the hot water storage tank. A disadvantage of this storage system is that the temperature of the water inside the hot water tank can not be exactly regulated. So, the warm water temperature can reach up to 95 C° which means that there is the danger of scalding oneself. For this reason one normally has to install a hot water mixer with which it is possible to regulate the temperature down to below 60 C°. The following diagram 31 shows the function of a combined storage system.
Diagram 31: Function of a "combined storage system"
|Brauchwasserspeicher||=||Storage tank for the hot water that is being used|
|Nachheizung||=||Additional heating system|
|Heizungswasser||=||Water that is part of the heating system circulation|
|Solarkreis||=||Solar energy circulation system|
The storage collector has already been discussed in the chapter "collector technology". Since it also represents a very inexpensive and simple storage solution some additional aspects shall be presented here. In storage collectors there is no glycol mixture being used as the heat carrying liquid. Instead, drinking water is being used for this purpose. So, a storage collector can directly be connected to the drinking water circulation system without needing any regulation technology and solar circulation system. For the installation it is recommendable to build in an expansion tank and a hot water mixing valve as a protection against scalding oneself. The storage collector is frost-resistant in Central Europe and so no further additional installation measures have to be taken in order to protect the collector against freezing up. Only the pipes of the system have to be protected correspondingly against frost. The very good general insulation of the storage collector and the transparent heat insulation in particular only allow a very low emission during the night-time. Storage collectors can be installed either in the roof, on the roof, in walls or integrated into the front of a building. The insertion into a roof is done in the same way as the installation of a roof top window: