Cooling Load Feedback Control for Chiller and Tower Setpoints
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Cooling systems in medium and large buildings often waste energy due to improper control, leading to undesirable temperature fluctuations in conditioned spaces and thermal variations in process loads.
Innovation Solution
A control system that detects actual end-use cooling loads and adjusts operational setpoints to reduce energy consumption, incorporating a chiller subsystem, cooling tower subsystem, air handling units, and a control system configured to evaluate cooling load values and calculate target setpoints for improved energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If cooling systems operate with fixed setpoints, then system operation is simple, but energy consumption increases and cooling effectiveness decreases
Solution Approach 1:
The control system dynamically adjusts operational setpoints based on real-time cooling load detection. The system transitions from fixed setpoints to variable setpoints that adapt to changing conditions, optimizing energy consumption while maintaining cooling effectiveness. This is achieved through continuous monitoring and adjustment of chiller, cooling tower, and pump operations.
Solution Approach 2:
The system implements feedback control by detecting actual cooling loads and using this information to adjust operational setpoints. The control system continuously monitors system performance and cooling demands, then modifies setpoints for chillers, cooling towers, and pumps to optimize energy consumption while meeting cooling requirements.
2Use of energy by moving object
If cooling systems reduce energy consumption through optimized control, then energy efficiency improves, but temperature control stability may deteriorate
Solution Approach 1:
The feedback control mechanism monitors temperature conditions and cooling loads continuously, adjusting setpoints to maintain temperature stability while optimizing energy consumption. The system responds to actual conditions rather than operating on fixed parameters, ensuring stable temperature control during dynamic adjustments.
Solution Approach 2:
The system uses dynamic setpoint adjustment to maintain temperature stability while reducing energy consumption. By continuously adapting operational parameters based on real-time conditions, the system avoids the temperature fluctuations that would result from fixed setpoints, particularly during transitional periods.
3Productivity
If operational setpoints are adjusted dynamically, then energy efficiency improves, but system control complexity increases
Solution Approach 1:
The control system is segmented into modular components that can be implemented independently or together. The dynamic setpoint adjustment is achieved through separate control modules for chillers, cooling towers, and pumps, each capable of operating autonomously or in coordination. This modular approach manages complexity while enabling energy efficiency improvements.
Solution Approach 2:
The control system is designed to be universally applicable to various cooling system configurations. The same control architecture can manage different types of chillers, cooling towers, and pump systems, reducing the complexity burden through standardized approaches that work across multiple equipment types and system designs.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The control system effectively reduces energy consumption while maintaining desired cooling demands, enhancing the overall energy efficiency of the cooling system by optimizing operational parameters such as chilled fluid temperature, flowrate, and condenser fluid conditions.
Implementation Method 1
The cooling coil is configured to receive a volume of chilled fluid from the chiller, and the fan is configured to deliver a volume of air or draw a volume of air past the cooling coil for heat exchange between the air and the chilled fluid.
Implementation Method 2
a chiller subsystem, which includes one or more absorption, constant speed, variable speed or other types of chillers
Implementation Method 3
a cooling tower subsystem, which comprises one or more cooling tower units
Implementation Method 4
one or more cooling tower units, which include a cooling tower inlet and outlet
Data Source
AI summary
A cooling system for providing conditioned air to a facility includes a chiller or other cooling subsystem, a cooling tower subsystem and one or more air handling units or process cooling units. The cooling subsystem may advantageously include one or more chillers (e.g., variable speed chillers, constant speed chillers, absorption chillers, etc.) and chilled fluid pumps. The cooling tower subsystem includes one or more cooling tower units and condenser fluid pumps. In some implementations, the air handling unit has a cooling coil and a variable volume fan. In some implementations, direct expansion (DX) cooling systems comprise compressors, evaporators and air-cooled, water-cooled or evaporatively-cooled condensing systems. Such systems can be controlled to reduce energy waste, improve occupant comfort and/or improve the thermal characteristics of the process cooling unit. The cooling system further comprises a control system which is configured to evaluate a cooling load value at the air handling unit and use the cooling load value to calculate at least one operational setpoint. The operational setpoint may advantageously be selected to improve the energy efficiency of the overall cooling system.