Development of an integrated loop control algorithm: Enhancing efficiency and expanding application range for water-side economizers

• Published in: International journal of refrigeration Vol. 177; pp. 29 - 39
• Main Authors: Kim, Kwang-hee, Kim, Yu-jin, Ha, Ju-wan, Song, Young-hak
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.09.2025
• Subjects: Advanced algorithm; Data center; Energy savings; Integrated loop control; Office buildings; Water-side economizer; Data center; Water-side economizer; Office buildings; Integrated loop control; Advanced algorithm; Energy savings
• ISSN: 0140-7007
• DOI: 10.1016/j.ijrefrig.2025.05.008

•Developed an Integrated Loop Control algorithm that can comprehensively control the three loops of a central cooling system: Condenser water, Chilled water, and Air loop.•Analyzed cooling operation and energy consumption in WSE (Water-Side Economizer) systems with the algorithm applied, targeting data centers and large office buildings.•Results showed that a control sequence improved the efficiency of system components, expanded the operational range of free cooling and suggested the feasibility of WSE application in office buildings. Water-side economizers (WSEs) are garnering attention as a means to reduce cooling energy costs in data centers. WSEs leverage free cooling to significantly reduce the use of chillers that are employed in conventional cooling systems. However, the application of WSE is somewhat limited, as free cooling depends heavily on climate and specific cooling load patterns. This study developed and introduced an integrated loop control algorithm to improve the system efficiency of a WSE and expand the target building to a general building, thereby analyzing the energy-saving effect. The integrated loop control algorithm performs integrated control of independent circulating cooling media that circulates condenser water, chilled water, and air loops, and considers the interaction between each loop. According to the energy analysis results of applying the algorithm, it was possible to reduce energy consumption by 16 % and 20 % in data centers and large offices, respectively, compared to conventional systems. In addition, it was expected that the free cooling operation time would be extended and the efficiency of the system components would be improved.