Vapor compression system
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Solution Overview
Problem
Conventional chilled liquid systems in heating, ventilation, and air conditioning (HVAC) systems face inefficiencies in thermal energy transfer and refrigerant management, particularly in evaporator designs where refrigerant distribution and level sensing are not optimally integrated with the compressor, condenser, and expansion devices.
Innovation Solution
The vapor compression system incorporates a shell with a horizontally extending tube bundle, a hood, a distributor, supply lines, a valve, and a sensor to regulate refrigerant flow and level, enhancing thermal energy transfer efficiency by optimizing refrigerant distribution and management through a hybrid falling film evaporator configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If refrigerant is sprayed or deposited onto exterior surfaces of tube bundle using conventional falling film evaporator design, then thermal energy transfer occurs, but refrigerant distribution and level sensing are not optimally integrated with compressor, condenser, and expansion devices
Solution Approach 1:
The patent implements feedback control by using level sensors to detect refrigerant levels in the evaporator and automatically adjusting the expansion device accordingly. This closed-loop system ensures optimal refrigerant management by continuously monitoring and adjusting refrigerant flow based on actual evaporator conditions, resolving the integration issue between level sensing and expansion device control.
Solution Approach 2:
The patent integrates multiple functions into a unified refrigerant management system where the expansion device serves both as a flow control mechanism and as a feedback-controlled actuator responsive to level sensor signals. This multi-functionality approach consolidates refrigerant distribution, level sensing, and flow regulation into an integrated system, improving reliability without proportionally increasing complexity.
2Productivity
If refrigerant level in evaporator is not monitored and controlled, then system operation is simpler, but heat transfer efficiency deteriorates due to inconsistent refrigerant distribution
Solution Approach 1:
The patent employs feedback control through level sensors that continuously monitor refrigerant levels in the evaporator and automatically adjust the expansion device to maintain optimal levels. This ensures consistent refrigerant distribution across the tube bundle, maximizing heat transfer efficiency while using automated control to minimize the operational complexity burden.
Solution Approach 2:
The refrigerant management system operates autonomously by using level sensor data to automatically control the expansion device, eliminating the need for manual intervention. The system self-regulates refrigerant flow to maintain optimal evaporator levels, improving heat transfer efficiency without requiring complex manual control procedures.
3Productivity
If expansion device is kept open to maximize refrigerant flow, then cooling capacity increases, but refrigerant level in evaporator drops below predetermined level
Solution Approach 1:
The patent uses feedback control where level sensors continuously monitor evaporator refrigerant levels and automatically adjust the expansion device opening accordingly. When levels drop below a predetermined threshold, the system reduces the expansion device opening to prevent further level decline, thereby maintaining reliable refrigerant levels while still allowing high cooling capacity operation under normal conditions.
Solution Approach 2:
The expansion device operates dynamically, adjusting its opening degree in real-time based on evaporator refrigerant level conditions. This dynamic control allows the system to maximize cooling capacity when levels are adequate while automatically reducing flow when levels drop, preventing the contradiction between high cooling capacity and level maintenance.
4Productivity
If refrigerant flow is dynamically adjusted based on sensed levels, then refrigeration cycle is optimized, but system complexity increases due to additional sensors and control mechanisms
Solution Approach 1:
The patent implements feedback control using level sensors and automated expansion device control to optimize refrigeration cycle efficiency. The system continuously monitors evaporator refrigerant levels and automatically adjusts expansion device opening to maintain optimal operating conditions, maximizing cooling efficiency while using automated control to minimize manual intervention requirements.
Solution Approach 2:
The refrigeration system operates autonomously with self-regulating refrigerant flow control based on level sensor feedback. The expansion device automatically adjusts its opening degree in response to evaporator level conditions, enabling the system to self-optimize refrigeration cycle efficiency without requiring complex manual control procedures or continuous operator intervention.
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 improves heat transfer efficiency, ensures consistent refrigerant levels, and enhances the overall performance of the vapor compression system by dynamically adjusting refrigerant flow based on sensed levels, thereby optimizing the refrigeration cycle.
Implementation Method 1
The sensor is configured and positioned to sense a level of liquid refrigerant in the shell
Implementation Method 2
The valve is configured and positioned to regulate flow in the second supply line in response to a sensed level of liquid refrigerant from the level sensor
Implementation Method 3
refrigerant can be deposited onto the exterior surfaces of the tube bundle by spraying or other similar techniques in what is commonly referred to as a 'falling film' evaporator
Implementation Method 4
The refrigerant is brought into contact with the outer or exterior surfaces of the tube bundle inside the shell, resulting in a transfer of thermal energy between the liquid to be cooled and the refrigerant
Implementation Method 5
The pump is operated in response to a sensed level of liquid refrigerant decreasing below a predetermined level when the expansion device is in an open position
Implementation Method 6
an expansion device and an evaporator connected by a refrigerant line
Implementation Method 7
the refrigerant is heated and converted to a vapor state, which is then returned to a compressor where the vapor is compressed, to begin another refrigerant cycle
Implementation Method 8
a condenser, an expansion device and an evaporator connected by a refrigerant line
Data Source
AI summary
An evaporator (168) in a vapor compression system (14) (168) includes a shell (76), a first tube bundle (78); a hood (86); a distributor (80); a first supply line (142); a second supply line (144); a valve (122) positioned in the second supply line (144); and a sensor (150). The distributor (80) is positioned above the first tube bundle (78). The hood (88) covers the first tube bundle (78). The first supply line (142) is connected to the distributor (80) and an end of the second supply line (144) is positioned near the hood (88). The sensor (150) is configured and positioned to sense a level of liquid refrigerant (82) in the shell. The valve (122) regulates flow in the second supply line in response to the level of liquid refrigerant (82) from the sensor (150).