Modeling and predicting energy consumption of chiller based on dynamic spatial-temporal graph neural network

As an important equipment in the HVAC system, the chiller accounts for 50-60 % of the total energy consumption. According to the characteristics of chiller operation data and using the multivariate time series (MTS) forecasting method, a novel chiller energy consumption prediction model (T-CADGCN) is proposed, which is based on the temporal convolution (TC) and the dynamic graph convolution (DGC) network with a channel attention (CA) mechanism. Two datasets are used to verify the prediction performance of different models. Compared with the actual energy consumption, the average MAPEs of the T-CADGCN model on the measured dataset and simulated dataset are 0.92 % and 0.08 %, respectively. Whereas they are 2.8 % and 0.91 % for LSTM, 11.45 % and 11.74 % for MTGNN_GCA, 12.3 % and 12.63 % for MTGNN, respectively. The results demonstrate that the T-CADGCN model can effectively enhance the prediction performance of chiller energy consumption, followed by LSTM, then MTGNN_GCA, and finally MTGNN. Besides, the prediction performance on different future time steps is also conducted on two datasets. It can be found that all models decrease in prediction accuracy with the increase of the prediction time steps, but the T-CADGCN model can maintain a relatively good prediction performance with high robustness. The changes of in-degree and out-degree in the chiller energy consumption node in the dynamic graph construction module indicate that the factors affecting and being affected by chiller energy consumption change over time. This study can help to predict the energy consumption of chiller accurately and thus contributes to building energy management.