Systems and methods for evaporative heat rejection equipment fan speed control
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Solution Overview
Problem
Traditional thermal management systems with evaporative heat rejection equipment focus solely on energy costs, neglecting water costs, leading to increased overall operating expenses and inefficient water usage, and fail to optimize energy and water costs under varying load and ambient temperature conditions.
Innovation Solution
A dynamic fan speed control system for evaporative heat rejection devices that adjusts fan speed based on relative humidity, percentage of refrigeration system capacity, water to energy cost ratio, and compressor to fan power ratio, minimizing total utility costs by optimizing energy and water usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If fan speed is increased to improve heat rejection efficiency, then cooling performance is improved, but energy consumption increases
Solution Approach 1:
The patent implements dynamic fan speed control that adjusts fan operation based on real-time system conditions including refrigeration load, ambient temperature, and humidity. The controller modulates fan speed dynamically rather than operating at fixed speeds, optimizing the balance between heat rejection efficiency and energy consumption across varying operating conditions.
Solution Approach 2:
The system changes operational parameters by adjusting fan speed based on multiple inputs including refrigeration system capacity percentage, ambient relative humidity, and temperature differentials. The controller modifies fan operation parameters dynamically to achieve optimal heat rejection while minimizing energy use according to actual system needs.
2Use of energy by moving object
If fan speed is decreased to reduce energy costs, then energy consumption is reduced, but water consumption in evaporative heat rejection increases
Solution Approach 1:
The system monitors ambient relative humidity and adjusts fan speed accordingly. When humidity is low, the controller increases fan speed to enhance evaporative cooling efficiency, thereby reducing water consumption. When humidity is high, the controller reduces fan speed to conserve energy while accepting increased water usage, optimizing the trade-off between energy and water costs.
Solution Approach 2:
The controller receives feedback from humidity sensors and refrigeration system performance data to continuously adjust fan operation. This closed-loop control ensures the system responds to changing environmental conditions and system load, dynamically optimizing the balance between energy consumption and water consumption in evaporative heat rejection.
3Use of energy by moving object
If traditional control based solely on energy costs is used, then energy optimization is achieved, but total operating costs increase due to neglected water costs
Solution Approach 1:
The patent merges energy cost optimization with water cost optimization into a unified control strategy. The controller simultaneously considers both energy consumption and water consumption when determining fan speed, combining multiple cost factors into a single decision-making framework that minimizes total operating costs rather than optimizing for energy alone.
Solution Approach 2:
The system incorporates water cost parameters into the control algorithm alongside energy cost parameters. By adjusting operational parameters based on both energy and water cost considerations, the controller achieves optimal total cost minimization, accounting for both utility expenses in its decision-making process.
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 system reduces overall operating costs and water consumption by dynamically adjusting fan speed, balancing energy and water usage, and optimizing the fan speed across a wider range of conditions, thereby lowering both energy and water costs.
Implementation Method 1
a fan configured to provide an entering airflow across the heat rejection device to cool a flow of water within the heat rejection device
Data Source
AI summary
A thermal management system includes a heat rejection device configured to fluidly couple to a refrigeration system, a fan configured to provide an entering airflow across the heat rejection device to cool a flow of water within the heat rejection device, and a controller configured to control a speed of the fan based on at least two of (i) a relative humidity of the entering airflow, (ii) a percentage of capacity one or more components of the refrigeration system are operating at, (iii) a ratio of water to energy costs, and (iv) a ratio of a design power of a compressor of the refrigeration system to a design power of the fan to minimize a total utility operation cost of the thermal management system including (i) energy costs to operate the fan and the refrigeration system and (ii) water costs of the flow of water.