Two-Stage Refrigerant Cooling for Sub-Ambient Gas Cooler Performance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional air conditioning systems face inefficiencies in cooling refrigerant, particularly in hot and dry climates, requiring significant energy and water resources, and existing systems lack effective methods to reduce refrigerant temperature below ambient levels for enhanced evaporator capacity.
Innovation Solution
The implementation of a multi-stage cooling system incorporating an auxiliary heat exchanger with fluid retention members and thermoelectric coolers, which reduces refrigerant temperature by heat transfer and evaporation, allowing the refrigerant to be cooled to a temperature close to or equal to ambient temperature, thereby increasing evaporator capacity and energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional air-cooled condensers are used to cool refrigerant, then the system can operate in hot and dry climates, but the refrigerant temperature cannot be reduced below ambient temperature and energy consumption is high
Solution Approach 1:
The cooling system is divided into two distinct stages: an air-cooled condenser for initial refrigerant cooling, and an evaporative condenser for further cooling below ambient temperature. This segmentation allows each stage to operate optimally within its designed temperature range, achieving sub-ambient cooling without excessive energy consumption.
Solution Approach 2:
The system changes the cooling mechanism parameter from purely air-cooled to a combination of air-cooled and evaporative cooled. By introducing water evaporation in the second stage, the system can achieve temperatures below ambient without requiring additional mechanical compression, thereby reducing energy consumption.
2Productivity
If evaporative cooling is used to reduce refrigerant temperature below ambient, then evaporator capacity increases, but water consumption increases significantly
Solution Approach 1:
The evaporative cooling is applied partially - only in the second stage and only to the extent needed to achieve sub-ambient temperatures. The system uses a water reservoir that is periodically replenished, rather than continuous water flow, reducing overall water consumption while still achieving the productivity benefit of increased evaporator capacity.
Solution Approach 2:
The system discards excess water through periodic draining and replenishment of the water reservoir, rather than attempting to recover and recycle all water. This practical approach balances water conservation with the need to maintain evaporative cooling functionality for enhanced evaporator capacity.
3Use of energy by moving object
If rapid temperature fluctuations occur in the refrigerant, then cooling efficiency may improve, but mechanical stress on equipment increases
Solution Approach 1:
The air-cooled condenser performs preliminary cooling of the refrigerant before it enters the evaporative condenser. This gradual temperature reduction prevents sudden thermal shocks to the equipment, maintaining reliability while still achieving high cooling efficiency through the subsequent evaporative cooling stage.
Solution Approach 2:
The two-stage cooling approach acts as a cushion against rapid temperature fluctuations. By transitioning gradually from air-cooled to evaporative cooling, the system prevents abrupt thermal changes that would otherwise cause mechanical stress, thereby protecting equipment lifespan while maintaining cooling efficiency.
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 energy efficiency ratio (EER) of air conditioning systems by increasing evaporator capacity without significant energy consumption, reduces water usage, and extends equipment lifespan by minimizing mechanical stress from rapid temperature fluctuations.
Implementation Method 1
an evaporative stage that cools the refrigerant discharged from the air-cooled stage
Implementation Method 2
A temperature of at least a part of the refrigerant in the refrigerant conduit may be reduced by heat transfer from the refrigerant to at least one of the fluid retention members
Implementation Method 3
Air may flow proximate the channels and at least partially evaporate the fluid at least partially retained in the channels to reduce a temperature of at least a part of the refrigerant
Data Source
AI summary
According to certain embodiments, a refrigeration system comprises first and second evaporators, first and second compressors, and a gas cooler. The first and second evaporators receive liquid refrigerant from a flash tank and evaporate the refrigerant to cool a first case and a second case, respectively. The second case has a higher temperature set point than the first case. The first compressor compresses the refrigerant discharged from the first evaporator. The second compressor compresses the refrigerant discharged from the first compressor, flash gas from the flash tank, and the refrigerant discharged from the second evaporator. The gas cooler comprises an air-cooled stage that cools the refrigerant discharged from the second compressor and an evaporative stage that cools the refrigerant discharged from the air-cooled stage. The gas cooler further comprises an outlet that supplies the cooled refrigerant to the flash tank through an expansion valve.