Variable Speed Pump Control for Gas Turbine Chilled Water Stratification
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Solution Overview
Problem
Chilled water storage tanks in power plants face challenges in maintaining temperature stratification, leading to inefficient use of chilled water, and there is a need for systems to quickly adjust power generation to match variable electricity demand and detect coil leaks in gas turbine systems.
Innovation Solution
A system utilizing variable speed drive controlled discharge pumps and a controller to manage the flow of chilled water from a storage tank to coils, maintaining temperature gradients and monitoring for leaks, allowing for efficient energy storage and usage during peak demand hours and adjusting power output to match demand.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If chilled water is stored in a tank for later use during peak demand hours, then energy efficiency is improved by utilizing off-peak electricity, but temperature stratification is lost due to mixing of water within the tank
Solution Approach 1:
The storage tank is divided into multiple zones with different temperature ranges (cold zone, intermediate zone, warm zone). Discharge pumps are positioned at different elevations to selectively draw from specific zones, preventing complete mixing and maintaining stratification structure
Solution Approach 2:
Variable speed drives act as intermediaries between the discharge pumps and the power grid, enabling precise control of pump speeds to match demand while maintaining optimal discharge rates that preserve stratification. The controller serves as an intermediary that coordinates pump operation based on temperature sensor feedback
2Productivity
If discharge pumps operate at high speed to meet peak electricity demand, then power output is increased, but temperature stratification deteriorates due to excessive water mixing
Solution Approach 1:
The discharge pumps are equipped with variable speed drives that allow dynamic adjustment of pump speeds based on real-time temperature measurements and power demand conditions. This enables the system to optimize between meeting power demand and preserving stratification by adjusting discharge rates dynamically
Solution Approach 2:
Temperature sensors positioned at multiple heights in the tank provide feedback to the controller, which adjusts pump speeds accordingly. When stratification degradation is detected, the controller reduces pump speeds to allow stratification recovery while still meeting power demand requirements
3Reliability
If coil leak detection is implemented to ensure safe operation, then system reliability is improved, but device complexity increases due to additional monitoring equipment
Solution Approach 1:
The system uses the existing chilled water circulation infrastructure to perform self-diagnosis for leaks. By monitoring temperature differentials across coils and analyzing flow patterns through the variable speed drive controllers, the system detects potential leaks without requiring separate complex detection equipment
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 solution enhances the efficiency of gas turbines by maintaining temperature stratification in chilled water storage tanks, enabling more electricity generation with less fuel and fewer emissions, while also ensuring reliable operation by detecting and addressing coil leaks.
Implementation Method 1
maintaining temperature gradients and monitoring for leaks
Implementation Method 2
The inlet air is passed over the coil to cool the air
Implementation Method 3
The inlet air is passed over the coil to cool the air
Data Source
AI summary
Variable speed drive controlled discharge pumps are used for pumping chilled water from a chilled water storage tank to coils operatively associated with the air inlet of a gas turbine, wherein the gas turbine is used to generate electricity. Use of the variable speed drive controlled discharge pumps aids is protecting the temperature distribution in the chilled water storage tank so that a thermocline rises with the addition of chilled water during charging of the tank with chilled water, and lowers during discharge of the tank when using the chilled water to cool inlet air at one or more gas turbines operated at a facility.