Integral Evaporator Header Heat Exchanger for Coil Superheat Relief
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Solution Overview
Problem
Conventional direct expansion refrigeration systems face inefficiencies due to superheating refrigerant inside evaporator coils, reducing capacity and efficiency, and existing solutions to improve efficiency, such as increasing coil surface area or fan speed, are costly or impractical, especially with space constraints and additional installation requirements.
Innovation Solution
An integral evaporator header liquid suction heat exchanger is integrated within the evaporator housing, where the refrigerant is superheated by a liquid line from the condenser, maintaining a two-phase state throughout the coils for enhanced heat transfer and efficiency without increasing coil surface area or fan power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the refrigerant is superheated inside the evaporator coils, then the refrigerant is prevented from entering the compressor in liquid state, but the evaporator capacity and efficiency are reduced
Solution Approach 1:
The patent divides the superheating function from the evaporator coils by adding a separate suction heat exchanger. The evaporator coils focus on cooling the air while the suction heat exchanger handles refrigerant superheating, allowing both functions to operate optimally without compromising evaporator capacity
Solution Approach 2:
The suction heat exchanger acts as an intermediary component between the evaporator and compressor. It uses the warm suction refrigerant to superheat the refrigerant leaving the evaporator, providing compressor protection while maintaining evaporator efficiency
2Productivity
If the surface area of the evaporator coils is increased, then the efficiency and capacity of the refrigeration system are improved, but the material cost and overall price increase
Solution Approach 1:
The suction heat exchanger uses the waste heat from the suction refrigerant itself to perform the superheating function. This self-service approach eliminates the need for additional heating components or external energy sources, improving efficiency without significant material cost increase
3Productivity
If the fan speed is increased, then the capacity of the refrigeration system is improved, but the power consumption increases
Solution Approach 1:
The patent changes the thermal parameters of the refrigerant through the suction heat exchanger, achieving better heat transfer efficiency. This allows the system to operate at lower fan speeds while maintaining capacity, as the improved refrigerant conditions enhance overall heat exchange effectiveness
4Reliability
If an external suction heat exchanger is installed, then the refrigerant superheating is improved, but the installation complexity and cost increase
Solution Approach 1:
The suction heat exchanger is merged with the existing evaporator assembly as an integrated unit. This combination eliminates the need for separate external installation, reducing installation complexity and cost while maintaining the refrigerant superheating function
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 increases evaporator efficiency and capacity by up to 5-20% while maintaining a compact design and minimizing costs, meeting regulatory efficiency requirements without expanding the system's footprint or requiring external installations.
Implementation Method 1
a liquid line from a condenser that is disposed in and passes through the evaporator header. The example integral evaporator header liquid suction heat exchanger is configured such that a refrigerant that enters the evaporator header from the evaporator coils is superheated by the liquid line passing through the evaporator header
Implementation Method 2
indoor evaporator unit with evaporator coils that are configured to pass a refrigerant therethrough. The refrigerant passing through the evaporator coils absorbs heat from air that is to be conditioned
Data Source
AI summary
An evaporator includes an integral liquid suction heat exchanger that is disposed in a housing of the evaporator. The integral liquid suction heat exchanger is defined by an evaporator header of the evaporator and a portion of a liquid line that extends through an inner cavity defined by the evaporator header such that: (a) the evaporator header and the portion of the liquid line form a tube-in-tube structure, and (b) refrigerant from the evaporator coils that is channeled into the inner cavity of the evaporator header is superheated and converted to a vapor state in the evaporator header by heat from the refrigerant flowing through the liquid line. The refrigerant flowing through the liquid line is in a liquid state and has a higher temperature than the refrigerant from the evaporator coils that is in a two-phase state.