Enhancing the reliability of chiller control using fused measurement of building cooling load

This paper presents a general framework of utilizing a fused measurement of the building instantaneous cooling load to improve the reliability of the chiller sequencing control in building automation systems. The fused measurement is obtained by combining the complementary advantages of two different approaches to measuring the building cooling load. One approach is the direct measurement, which calculates the building cooling load directly, using the differential water temperature and water flow rate measurements. The other is the indirect measurement, which calculates building cooling load based on chiller models using the instantaneous chiller electrical power input, etc. The combination strategy is tested using the field data collected from the central plant of the air-conditioning system in a high-rise building in Hong Kong. The confidence degree associated with the fused measurement is systematically evaluated. Periodic update of the fusion algorithm parameters is also developed to improve the performance of the fusion strategy and the chiller sequencing control.