5. Conclusions and future work
The proposed optimization method in this study for a VRF and
VAV combined air conditioning system is verified that it could
efficiently optimize the results both in cooling and heating
conditions. Test results indicated that the optimized OA supply
temperature can significantly reduce the energy consumption
by improving the energy efficiency of the combined system.
Results showed that both the daily and the real-time
optimal control strategy are superior to that of the benchmark
control strategy. If the optimal temperature set-point can
be used during actual operations,much energy can be saved. In
addition, compared to daily optimization of the OA supply
temperature, it can save more energy by optimizing the OA
supply temperature in real-time. Although the energy saving
percentage in heating mode is not as significant as in cooling
mode, it is still an improvement in energy conservation.
Results alsofound that theproposedoptimal control strategy
is able to adjust the system to operate with high efficiency by
allocating suitable load between the VRF unit and the OAP unit.
In this paper, a simplified but effective optimal control
strategy is discussed. The work and conclusions of this study
need to be verified by future studies under controlled laboratory
conditions and in real buildings.