# A robust online refrigerant charge fault diagnosis strategy for VRF systems based on virtual sensor technique and PCA-EWMA method

> Research article (Applied Thermal Engineering, 2017) · cited 48× · AI/ML

**Wikidata**: [openalex:W2595996626](https://www.wikidata.org/wiki/openalex:W2595996626)  
**Source**: https://4ort.xyz/entity/a-robust-online-refrigerant-charge-fault-diagnosis-strategy-for-vrf-systems-based-on-virtual-sensor-technique-and-pca-ew