Different water storage types for both short-term and long-term heat storage are introduced as well as basic design rules for water stores. Both water stores for solar domestic hot water systems and for solar c.
The heat content of the hot water store in a specific temperature interval from Tmin to Tmax is determined by the product of the heat storage capacity and the temperature difference (Tmax – Tmin).
The most important thermal characteristics for hot water stores are: heat storage capacity, heat loss, heat exchange capacity rates to and from the hot water storage and temperature stratification in the hot water store.
How does a thermal energy storage system work?
A typical thermal energy storage system is often operated in three steps: (1) charge when energy is in excess (and cheap), (2) storage when energy is stored with no demand and (3) discharge when energy is needed (and expensive).
What is hot water storage & how does it work?
As with chilled water storage, water can be heated and stored during periods of low thermal demand and then used during periods of high demand, ensuring that all thermal energy from the CHP system is eficiently utilized. Hot water storage coupled with CHP is especially attractive in cold northern climates that have high space heating requirements.
How thermal stratification can be established during Operation of the energy system?
During operation of the energy system, thermal stratification can be established in the hot water store, that is the temperature in the upper part of the hot water store is high and the temperature in the lower part of the hot water store is low. If this is compared with the above-mentioned conditions, it is essential that:
The hot water stores are normally insulated with an insulation material with a low thermal conductivity in order to reduce heat losses of the stores. Normally the tank material or the material enveloping the water volume as well as all the equipment inside the heat store is heated to the same temperature as the water in the hot water store.