Modeling and Design of Net ZEBs as Integrated Energy Systems - Modeling, Design, and Optimization of Net-Zero Energy Buildings - page 72

Fig. 2.20 Schematic of storage tank for DHW application
A storage tank is used to store a hot or cold medium for use in a process.
The most common application is storage for domestic hot water ( Figure
2.20 ). It consists of a fluid that circulates into the storage tank and delivers/
recuperates energy to/from the storage medium and exits the tank. Heat
exchanges between the fluid and the storage medium can be done through a
heat exchanger or by direct contact; thus, different types of heat exchangers
exist as follows:
- Storage tank without heat exchanger: heating or cooling fluid is the
same as the storage medium. The fluid entering the storage tank mixes
with the storage medium, delivers/recuperates energy, and exits the
storage tank.
- Storage tank with one heat exchanger: a heat exchanger inside the
storage tank ensures the heat exchange between the heating/cooling
fluid and the fluid in the storage tank.
- Storage tank with two heat exchangers: two heat exchangers inside
the storage tank permit a heat exchange of the storage mass with two
sources at different temperatures.