Air conditioning system with cooling capacity modulation via fixed pump operation and variable condenser fan operation
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Solution Overview
Problem
Traditional cooling systems face limitations in cooling capacity control, particularly in pumped refrigerant economizer mode, where changing pump speed has limited effect on cooling capacity and are sensitive to temperature and air flow changes, leading to inefficiencies and potential freezing of liquid lines.
Innovation Solution
The system includes a control module that adjusts the speed of condenser fans and pumps based on a requested cooling percentage, operating in pumped refrigerant economizer or mixed modes to optimize cooling capacity and efficiency, ensuring stable operation and preventing fluid line freezing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If pump speed is reduced to save energy in pumped refrigerant economizer mode, then energy consumption decreases, but cooling capacity control becomes limited and system becomes sensitive to temperature and air flow changes
Solution Approach 1:
The system dynamically adjusts condenser fan speed based on cooling load requirements while maintaining pump at full speed. This dynamic adjustment of the fan speed provides continuous cooling capacity modulation without reducing pump speed, thereby maintaining system stability and reliability while achieving energy savings through variable fan operation rather than pump speed reduction.
Solution Approach 2:
The invention changes the control parameter from pump speed to condenser fan speed for cooling capacity modulation. By varying the condenser fan speed parameter while keeping the pump running at full speed, the system achieves energy efficiency improvements without compromising the stability and reliability that would result from pump speed reduction.
2Use of energy by moving object
If pump speed is reduced to save energy, then energy consumption decreases, but liquid lines may freeze due to insufficient cooling fluid flow
Solution Approach 1:
The system uses dynamic condenser fan speed adjustment to match cooling load while maintaining constant pump operation. This ensures continuous adequate cooling fluid flow through the liquid lines, preventing freezing conditions that would occur with reduced pump speed, while still achieving energy savings through the variable fan operation.
Solution Approach 2:
The condenser fan acts as an intermediary control element between the cooling load requirements and the pump operation. By adjusting fan speed rather than pump speed, the system indirectly controls cooling capacity while maintaining the pump's ability to provide sufficient fluid flow to prevent liquid line freezing.
3Productivity
If condenser fan speed is increased to boost cooling capacity, then cooling capacity increases, but energy consumption increases
Solution Approach 1:
The system employs dynamic condenser fan speed adjustment that matches the cooling load requirements. The fan operates at variable speeds rather than fixed high speed, providing continuous cooling capacity modulation. This dynamic operation achieves the required cooling capacity while minimizing energy consumption by avoiding excessive fan speeds.
Solution Approach 2:
Instead of always operating the condenser fan at maximum speed to ensure sufficient cooling capacity, the system applies partial action by adjusting fan speed to match actual cooling needs. This prevents excessive energy consumption while maintaining adequate cooling capacity through proportional fan operation rather than constant maximum operation.
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 enhances energy efficiency by running condenser fans at variable speeds and maintaining pumps at full speed, reducing energy consumption and maintaining stable cooling fluid flow, thus improving overall system performance and preventing fluid line freezing.
Implementation Method 1
The first condenser fan module is configured to control a first condenser fan to transfer air across a first condenser of the first cooling circuit
Implementation Method 2
The first pump module is configured to control a first pump to pump a first cooling fluid through a first cooling circuit
Implementation Method 3
The evaporator 54 receives the cooling fluid and cools air passing through openings in evaporator 54
Data Source
Figure 1
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AI summary
A cooling system is provided and includes pump, condenser fan, and control modules. The pump module controls a pump to pump a cooling fluid through a cooling circuit. The condenser fan module controls a condenser fan to transfer air across a condenser of the cooling circuit. The control module, while operating in a pumped refrigerant economizer mode or a mixed mode, determines a requested CFC percentage. The pump module activates the pump if the requested CFC percentage is greater than or equal to a predetermined CFC percentage. The condenser fan module: if the requested CFC percentage is greater than or equal to the predetermined CFC percentage, activates the condenser fan or operates the condenser fan at least at a minimum speed; and based on the requested CFC percentage, adjusts a speed of the condenser fan between the minimum speed and a maximum permitted speed to provide the requested CFC percentage.