Further Explorations Expansion Tanks on Large Campus Thermal Loops

Expansion tank size is crucial for thermal loop operation. The size directly affects the performance and stability of the system pressure and volume, as well as cost. Understanding the sizing formulas is vital in thermal loop design. Discussions with design and plant engineers revealed a significant amount of confusion when using the ASHRAE expansion tank sizing formulas(1) for different systems, particularly regarding the selection of input parameters such as temperature ranges and tank pressures, leading to excessively large tank sizes. And, Texas A&M University experienced similar confusion in attempting to improve thermal loop performance and verify existing tanks. Due to these concerns, a thorough study of the ASHRAE formulas was performed.