Hi, I am using Tank 3.0 for calculations and I don´t know what it means the 4 point, DELTA TEMPERATURE (Enter the difference between the normal operating temperature and the installation temperature), specifically the INSTALATION TEMPERATURE.

I hope that you can help me.

In order to determine the thermal effects on the tank, you need to define the "delta T", and specify this as input. Typically the "installation temperature" is ambient - say 21 degC. If your fluid is at 41 degC, then your "delta T" would be 20 degC.