Cooling systems and methods incorporating a plural in-series pumped liquid refrigerant trim evaporator cycle
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Solution Overview
Problem
Conventional cooling systems are inefficient under varying load conditions and in diverse environmental settings, leading to increased energy consumption and maintenance costs, particularly in low-loading or high-latent environments, due to limitations in compressor control and refrigerant system operation.
Innovation Solution
A dual pumped liquid refrigerant system with primary and secondary evaporator coils in series, along with a trim compression cycle, which adjusts heat load capacity based on environmental conditions to optimize cooling efficiency and reduce compressor load, utilizing a fluid cooler for free cooling and incremental cooling through the secondary evaporator coil when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional cooling systems operate under low-loading conditions, then cooling capacity is reduced, but energy consumption per ton of cooling increases dramatically
Solution Approach 1:
The cooling system is divided into multiple independent evaporator coils (first, second, third) that can operate independently or in combination. This segmentation allows the system to provide precise partial cooling capacity by activating only the necessary number of evaporators, avoiding the need to run the full system at low load and thereby reducing energy consumption per ton of cooling provided.
Solution Approach 2:
The system dynamically adjusts the number of active evaporator coils based on the cooling load demand. Control logic enables seamless transition between one, two, or three evaporators operating simultaneously, allowing the system to maintain high efficiency across a wide range of loading conditions from 15% to 100% capacity.
2Reliability
If compressors use tight control of vapor evaporated with metering devices, then refrigerant control is improved, but liquid slugging to compressor can occur which damages the compressor
Solution Approach 1:
The system removes the traditional metering device (expansion valve) from the refrigerant circuit and replaces it with independently controlled evaporator coils. Each evaporator receives refrigerant through separate liquid lines with individual solenoid valves, eliminating the need for complex metering control and preventing liquid slugging by ensuring proper refrigerant distribution to each evaporator based on its specific load requirements.
Solution Approach 2:
The system introduces independently controlled liquid refrigerant lines and solenoid valves as intermediaries between the refrigerant source and each evaporator coil. This intermediary control mechanism allows precise regulation of refrigerant flow to each evaporator without requiring tight metering control, preventing liquid slugging while maintaining operational flexibility.
3Reliability
If hot gas bypass and low ambient kits are added to combat inflexibility problems, then compressor protection is improved, but energy consumption increases and false load is created
Solution Approach 1:
The system removes the need for hot gas bypass valves, low ambient kits, and other energy-consuming protective devices by using independently controlled evaporator coils. Each evaporator can be individually activated or deactivated based on load conditions, providing inherent protection against compressor damage without requiring additional energy-robbing circuit devices.
Solution Approach 2:
The independently controlled evaporator system is self-regulating and does not require external protective devices like hot gas bypass or low ambient kits. The system automatically adjusts to varying load conditions and environmental temperatures by selectively operating the appropriate number of evaporators, eliminating false load and reducing energy consumption while maintaining compressor protection.
4Device complexity
If conventional systems are used in variable temperature climates, then system simplicity is maintained, but cooling efficiency decreases and maintenance costs increase
Solution Approach 1:
The cooling system is segmented into multiple independently controlled evaporator coils that can operate in various combinations. This segmentation allows the system to maintain high cooling efficiency across variable temperature climates by activating only the necessary number of evaporators based on ambient conditions and load requirements, avoiding the efficiency penalties of conventional single-system designs.
Solution Approach 2:
The system dynamically adapts to variable temperature climates by controlling the operation of individual evaporator coils based on ambient conditions and cooling load. This dynamic operation maintains optimal efficiency across a broad spectrum of environmental conditions without increasing maintenance costs or system complexity.
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 reduces energy consumption by up to 90% compared to traditional systems, enhances cooling efficiency across a broad spectrum of conditions, and minimizes maintenance costs by optimizing compressor operation and heat rejection processes.
Implementation Method 1
A first evaporator coil in thermal communication with an air intake flow to a heat load, a first liquid refrigerant distribution unit in thermal communication with the first evaporator coil
Implementation Method 2
a second evaporator coil disposed in series with the first evaporator coil in the air intake flow and in thermal communication with the air intake flow to the heat load
Implementation Method 3
a fluid cooler for free cooling a first fluid circulating through the first and second liquid refrigerant distribution units
Implementation Method 4
The trim compression cycle of the second liquid refrigerant distribution unit is configured to incrementally further cool the air intake flow through the second evaporator coil when the temperature of the free-cooled first fluid flowing out of the second liquid refrigerant distribution unit exceeds a predetermined temperature
Data Source
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AI summary
The cooling systems and methods of the present disclosure relate to a plural in- series pumped liquid refrigerant trim evaporator cycle that may be incorporated into an existing cooling system to increase the efficiency of the existing cooling system. The cooling systems of the present disclosure include a first evaporator coil in thermal communication with an air intake flow to a heat load, such as a heat load being cooled by the existing cooling system, and a first liquid refrigerant distribution unit in thermal communication with the first evaporator coil. The cooling systems further includes a second evaporator coil disposed in series with the first evaporator coil in the air intake flow and in thermal communication with the air intake flow, and a second liquid refrigerant distribution unit in thermal communication with the second evaporator coil. A trim compression cycle of the second liquid refrigerant distribution unit is configured to incrementally further cool the air intake flow through the second evaporator coil when the temperature of the free-cooled first fluid flowing out of the main compressor of the second liquid refrigerant distribution unit exceeds a predetermined threshold temperature.