Generic simulation model of multi-evaporator variable refrigerant flow air conditioning system for control analysis

• Models of components to whole system of multi-evaporator variable refrigerant flow system are developed.
• Two system models are compared in computation speed.
• System models are generic that they are component-number independent.
• Models are validated with high accuracy and tested with good ability responding to varying conditions.
• Models can not only predict the performances but catch the dynamic trends of the multi-split variable refrigerant flow system.

Generic simulation models noted as AGM-I and AGM-II for performance and control analysis of variable refrigerant flow (VRF) systems were developed. Firstly, simulation models from component to whole VRF system were addressed. Then the simulation models were validated using experimental data reported in an open literature. The average error percentages to predict system cooling capacity, energy consumption and COP are 4.69%, 4.64%, 1.19%, respectively. Finally, tests were carried out. Results show that the developed models are fast computing and evaporator-number independent. From the computation speed point of view, the AGM-I is more suitable for multi-evaporator VRF system, while the AGM-II is more suitable for the one evaporator VRF system. Test results also show the system models good ability responding to varying conditions, including inlet air temperature of the evaporator, outdoor air temperature, opening of the EEVs and compressor speed, which are all very important variables for the control analysis.

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