Performance attenuation of multi-split variable refrigerant flow units affected by length of refrigerant pipeline

Establishes a lumped parameter mathematical model considering the resistance along the refrigerant pipeline and performs an experimental study of a multi-split variable refrigerant flow (VRF) system. Quantitatively investigates the influences of the length of refrigerant pipeline connecting the outdoor and indoor units on cooling capacity, heating capacity and input power under the nominal cooling and heating conditions. The results show that when there is no subcooler in the outdoor unit, the attenuation rates of cooling capacity and heating capacity are 0.15 to 0.18 %/m and 0.08 to 0.12 %/m respectively, and the decrease rate of input power is 0.08 to 0.10 %/m. Proposes to install a subcooler in the outdoor unit.