Systems and methods for cooling electrical equipment
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Solution Overview
Problem
Conventional cooling systems face inefficiencies and high energy costs due to their inability to scale down well under light loading conditions, leading to increased energy use per ton of cooling, and are not efficient at low ambient temperatures or 'shoulder seasonal' operations.
Innovation Solution
The cooling system incorporates a first refrigerant circuit, a free cooling circuit, a chilled water circuit, and a second refrigerant circuit, with control valves managing the flow between these circuits to optimize condensation based on ambient temperature, allowing for efficient 'free' cooling and mechanical cooling under varying conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional cooling systems operate under light loading conditions, then cooling capacity is reduced, but energy use per ton of cooling increases dramatically
Solution Approach 1:
The system dynamically switches between different cooling modes (free cooling, evaporative cooling, mechanical cooling) based on ambient conditions and load requirements. The free cooling mode uses ambient air directly when conditions permit, while evaporative cooling adds moisture to cool air when ambient temperatures are moderate, and mechanical cooling engages when high cooling capacity is needed regardless of ambient conditions.
Solution Approach 2:
The cooling system integrates multiple cooling functions into a single system that can operate in different modes: free cooling using ambient air, evaporative cooling using water evaporation, and mechanical cooling using refrigerant cycles. This multi-functional approach allows the system to optimize energy efficiency across varying load conditions and ambient temperatures.
2Temperature
If conventional refrigerant systems operate at low ambient temperatures, then cooling capacity is reduced, but additional energy-consuming devices are required
Solution Approach 1:
The system changes operational parameters based on ambient temperature conditions. During shoulder seasonal operation or low ambient temperatures, the control system adjusts refrigerant flow rates, compressor speed via VSD, and evaporation temperatures to maintain efficient operation without requiring additional energy-consuming heating devices.
Solution Approach 2:
The control system continuously monitors ambient temperature, cooling load, and system performance parameters, then automatically adjusts operating conditions to maintain optimal efficiency across varying ambient temperatures and load conditions.
3Manufacturing precision
If metering devices are used to control refrigerant flow in evaporators, then heat distribution improves, but liquid slugging to compressor can occur under low loading
Solution Approach 1:
The system uses dynamic control of refrigerant flow through the evaporator based on real-time load conditions. During low loading conditions, the system adjusts metering device opening, compressor speed, and suction pressure to maintain proper refrigerant flow rates that prevent liquid slugging while ensuring complete evaporation of refrigerant for uniform heat distribution.
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 configuration maximizes free cooling during low wet-bulb temperatures and switches to chilled water cooling during high wet-bulb temperatures, achieving improved efficiency and reduced energy costs across a broad range of operational conditions.
Implementation Method 1
The free cooling circuit is in fluid communication with the main condenser and a free-cooled water source. The free cooling circuit is in thermal communication with the first refrigerant circuit via the main condenser.
Implementation Method 2
a refrigerant of the first refrigerant circuit to be condensed by a fluid flowing through the main condenser that is cooled by the chilled water circuit
Implementation Method 3
The expanded liquid absorbs the heat present in the evaporator coil and leaves the coil as a super-heated vapor.
Data Source
AI summary
The cooling systems of the present disclosure include a first refrigerant circuit in thermal communication with a heat load and in fluid communication with a main condenser, a free cooling circuit in fluid communication with the main condenser and a free-cooled water source, a chilled water circuit in fluid communication with the main condenser and an evaporator, and a second refrigerant circuit in fluid communication with the evaporator and a secondary condenser. The free cooling circuit is in thermal communication with the first refrigerant circuit via the main condenser, the chilled water circuit is in thermal communication with the first refrigerant circuit via the main condenser, and the second refrigeration circuit is in thermal communication with the chilled water circuit and the free cooling circuit. The second refrigeration circuit cools a fluid flowing in the chilled water circuit. Methods of operating a cooling system are also disclosed.