How can I calculate the size for chiller and AHU unit PIPE :) :) ?

Hi, for your question, you have to refer to some professional book. I can give u some guild so you can get those information easier. Most of the chiller and AHU are using water cooling pakage to condense the gas (cooling tower) WCPU and air cooling pakage ACPU, and its calculate by using water tonage and sizes of fan. The sizes of those pipe line are depends on the tonage of cooling tower. Chiller and AHU are clasify by the cool air's flow rate (BTU- British Thermal Unit). To decide the sizes of chiller, consider these- occupying area(indoor,outdoor); heat transfer (condution/ convection, radiation) from wall, window, roof (heat transfer coefision); environment condition (dry pulp temp, wet pulp temp, humidity); occupying condition (room or hall or what). There is a chart call Phychometry Chart, you can get it from any air conditioning engineering book.