air conditioning system

Last Tuesday, I attended a power breakfast which organised by Trane Malaysia. The speaker was their Director. The seminar was really useful and valueable.
The new technology that being used by Trane can now produce chilled water at a lower temperature compared to the conventional chiller. The normal design chilled water supply temperature is 44 deg F, whereas the chilled water return temperature is 54 deg F. The temperature difference is 10 deg F. But now, Trane's chiller can produce a higher temperature difference at 16 deg F, which chilled water supply temperature can reduce to 42 deg F and the chilled water return temperature can be increased to 58 deg F. Since the chilled water flowrate depends on the temperature difference, therefore, the pipe size can be reduced and the installation and material costs will be lowered. Besides, a smaller pump will be installed too.
The formulae involved is:

Water flow rate, usgpm = tonnage x 24/ delta T.

If the delta T is a bigger value, then the required chilled water flow rate will be lesser. Therefore, we need a small chilled water pipe size.