| Popis: |
Theoretical development and a practical design process, accompanied with easy-to-apply data, are introduced in three parts for some representative and practical types of water thermal storage tanks. The first part describes basic design concepts, system composition and controls, characteristics of the most popular multi-connected complete mixing tanks, and the practical estimation table of storage efficiencies of this type. In part 2, a theoretical mixing model was developed for the temperature-stratified type of thermal storage water tank. Empirical equations consisting of the model parameter and input conditions were derived from a number of experiments under the stepwise temperature input. The model was further extended to be applied to various input conditions. The effects of various design parameters on storage efficiency were examined statistically with experimental designs through numerical simulations, which resulted in estimation tables of the storage efficiency of this type. In part 3, it is revealed that a self-balanced type of stratified tank, which is composed of main tank and subheaders that accept returned chilled/heated water, maintains stable stratification regardless of the type of imposed inlet condition. The performance was tested by experiment and compared with numerical simulation results. An estimation table consisting of two-level factors was prepared through system simulation with the help of design of experiment as introduced in the two preceding parts, and was made comparable with the simple temperature-stratified tanks as described in part 2. |
