hi guys.... am working on a variable refrigerant flow (VRF) type air conditioner. my aim is to change the capacity of the compressor based on load change. i can vary compressor capacity by using inverter....now my doubt is on what basis i should change compressor speed for muti evaporator system....i have one method. it is varying compressor speed based on suction superheat.... assume that am using single compressor with 1 evaporator system (single evaporator)....now first thing i will do is 1)sense suction pressure and convert that to corresponding saturated suction temperature (Ts) 2)next i will sense evaporator temperature(Te) 3) am finding superheat by SH=Ts-Te 4)i will be comparing SH with target superheat SHS...if SH>SHS i will increase compressor speed else i will decrease compressor speed........NOW CONSIDER SINGLE COMPRESSOR WITH 3 EVAPORATOR SYSTEM...now i will have three superheat value..BIGGEST DOUBT IS SHOULD I ADD SH1+SH2+SH3 and then compare with target value to change speed of compressor??