Local Vs. Integrated Control of a Cooling System in a Factory building

Large commercial buildings are usually equipped with multiple chillers, pumps, fans, and cooling towers. In general, each group of devices is independently controlled based on pre-determined rules with inputs of thermal states of both supply and demand sides. This local optimization determines contr...

Full description

Saved in:
Bibliographic Details
Published in:ASHRAE transactions 2023, Vol.129 (2), p.752-759
Main Authors: Kim, Young-Sub, Park, Cheol-Soo, Park, YongSung, Kim, Jin-Hong, Urabe, Eiji, Jo, Hyeong-Gon, Gwak, JeongHun
Format: Article
Language:English
Subjects:
Air conditioners
Centrifugal pumps
Chillers
Commercial buildings
Commercial real estate
Construction industry
Control systems
Cooling
Cooling systems
Cooling towers
Cooling water
Design specifications
Devices
Energy consumption
Energy management systems
Heat transfer
HVAC
Load
Local optimization
Optimal control
Optimization techniques
Pumps
Simulation
Supply and demand
Water temperature
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Large commercial buildings are usually equipped with multiple chillers, pumps, fans, and cooling towers. In general, each group of devices is independently controlled based on pre-determined rules with inputs of thermal states of both supply and demand sides. This local optimization determines control variables of the individual devices as prescribed in the design specifications. However, the states in the operation stage are time-varying and thus, the local rule-based control could be far sub-optimal compared to a global integrated control of the whole cooling system. In this regard, the integrated control should be designed to consider the dynamic correlation among the device groups as well as simultaneously find a set of optimal control variables for the whole cooling system. In this study, the authors investigated local vs. integrated control of a cooling system for a large factory building in South Korea. The building is air-conditioned with eight centrifugal chillers, five cooling towers, six cooling water pumps, and seven chilled water pumps. The existing local control determines the number of operating devices and control variables of individual device, e.g. cooling tower fan speed (three steps), chilled water set-point temperature, based on temperatures and the pressures measured at the outlet head of the device group. In contrast, the integrated control reflects dynamic relationship and find dynamic operation strategies between the group of devices. For this purpose, the authors developed a set of data-driven simulation models to account for dynamic behavior of the chillers, cooling towers, fans, and pumps in the factory building. It was found that the integrated control could save cooling energy by up to 21% compared to the existing local control. In the paper, the authors elaborate how the integrated control was developed as well as the pros and cons of the local vs. the proposed integrated control are addressed.
ISSN:0001-2505