Systems and methods for reducing energy consumption of a chilled water distribution system
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Solution Overview
Problem
Conventional chilled water distribution systems face issues with high water supply pressures, leading to increased maintenance costs, system complexity, and over-cooling due to the need for pressure-reducing valves, which also elevate capital costs and reduce operational life.
Innovation Solution
A chilled water distribution system with a monitoring and control system that uses variable frequency drives to modulate the speed of chiller station components, such as pumps and fans, to maintain a desired differential pressure range, optimizing chiller output while minimizing energy consumption by adjusting the number of operational chiller stations based on real-time load demands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If pressure reducing valves are installed to drop incoming chilled water pressures, then the water supply pressure is reduced to acceptable levels, but capital costs and system control complexity increase
Solution Approach 1:
The patent removes pressure reducing valves from the system entirely by using variable speed pumps to generate water supply pressure directly at the required level. This extracts the problematic pressure reduction function and replaces it with a more efficient pressure generation approach at the source.
Solution Approach 2:
The patent replaces the mechanical pressure reducing valve system with an electronically controlled variable speed pump system. This substitution uses motor control and sensors to dynamically adjust pump speed, eliminating the need for mechanical pressure reduction components and their associated complexity.
2Stress or pressure
If pressure reducing valves are installed to drop incoming chilled water pressures, then the water supply pressure is reduced to acceptable levels, but installation costs increase
Solution Approach 1:
The patent removes pressure reducing valves from the system entirely by using variable speed pumps to generate water supply pressure directly at the required level. This extracts the problematic pressure reduction function and replaces it with a more efficient pressure generation approach at the source.
3Productivity
If high water supply pressures are maintained in the chilled water system, then the system can deliver adequate flow to all buildings, but operational life is reduced and maintenance costs increase
Solution Approach 1:
The patent implements dynamic pressure control by using variable speed pumps that adjust their output based on real-time system conditions and building requirements. This allows the system to maintain adequate flow delivery while operating at lower, less damaging pressures, thereby extending operational life and reducing maintenance needs.
Solution Approach 2:
The patent changes the operating parameters of the water supply system by using variable speed motors to dynamically adjust pump speed and resulting pressure. This allows the system to adapt pressure levels to actual demand, maintaining productivity while reducing the harmful effects of consistently high pressure on system reliability.
4Stress or pressure
If pressure reducing valves are installed to drop incoming chilled water pressures, then the water supply pressure is reduced to acceptable levels, but the valves may not adequately close off against high pressures causing over-cooling
Solution Approach 1:
The patent replaces the mechanical pressure reducing valve system with an electronically controlled variable speed pump system. This substitution uses motor control and sensors to dynamically adjust pump speed, eliminating the need for mechanical pressure reduction components and their associated control effectiveness issues.
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
This approach reduces energy consumption, lowers maintenance costs, and maintains system stability by optimizing chiller station output and adjusting to fluctuating building loads, thereby reducing overall energy use and production costs.
Implementation Method 1
A chilled water distribution system includes a chilled water loop in fluid communication with a plurality of buildings and also in fluid communication with a plurality of chiller stations. A monitoring and control system communicates with one of the chiller stations, hereinafter referred to as a 'controlled' chiller station because it is configured with one or more variable frequency drives that are controlled by the monitoring and control system to modulate the speed of at least one chiller station component such as, but not limited to, a pump or a fan.
Implementation Method 2
In another aspect of the invention, a distributed process chilled water system includes a supply line having a supply line pressure sensor; a return line having a return line pressure sensor, the supply line pressure sensor and the return line pressure sensor cooperating to provide a differential pressure between the supply line and the return line
Data Source
AI summary
A chilled water distribution system includes a chilled water loop in fluid communication with a plurality of buildings and also in fluid communication with a plurality of chiller stations. A monitoring and control system communicates with one of the chiller stations, hereinafter referred to as a “controlled” chiller station because it is configured with one or more variable frequency drives that are controlled by the monitoring and control system to modulate the speed of at least one chiller station component such as, but not limited to, a pump or a fan. By way of this modulation process, a differential pressure of the chilled water loop may be maintained at a desired level so as to optimize chiller station output while minimizing chiller station energy consumption.