Moreover, it can be seen from the above figure that the system operation is not restricted if one of the evaporator units fails. It is due to the property of multi-split system obtained through the separation tubes or headers. Thus, the VRF system could provide a reliable operation; and the cooling output is dependent on the properties of condenser and evaporator units.
Figure 8 represents a configuration of both separation tubes and headers.
Figure 8 VRF separation tubes and headers
The control of VRF system is achieved through the EEV/PMV and compressor. The expansion valve as well as the compression work defines the refrigeration cycle efficiency and capacity. Thus, varying these parameters could alter the cooling capacity and the efficiency of the system. It is complex control system and an appropriate design is necessary to provide sensible operation. Therefore, it is important to make sure that these components are properly selected together with VRF system from various manufacturers’ catalogues.
A key parameter which defines the VRF system capacity is the coefficient of performance (COP) and energy efficiency ratio (EER) which depends on the properties and design of system’s components and operating temperatures. As the design of air conditioning cooling for the office building only concerns the output capacities, the key parameters of 19
