Pumped Two-Phase Heat Exchanger for Reversible Vertical Heat Flow
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Solution Overview
Problem
Existing vertical air to air heat pipe heat exchangers can only transfer heat in one direction due to reliance on gravity, limiting their functionality when the evaporator is above the condenser, and require complex and expensive designs with separate coils and pumps to overcome this limitation.
Innovation Solution
A pumped two-phase air to air heat exchanger with an upper and lower liquid header, featuring straight heat pipes with fins for evaporator and condenser sections, and a pump to reverse the direction of heat flow based on ambient conditions, allowing operation in adverse gravity orientations by recirculating fluid with the help of a pump.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If gravity is used to return condensed working fluid from condenser to evaporator, then the design is simple and reliable, but the heat exchanger can only operate in one direction with condenser above evaporator
Solution Approach 1:
The system dynamically switches between gravity-driven operation (simple mode) and pump-assisted operation (versatile mode) based on operating conditions. The pump is selectively activated to enable bidirectional heat transfer, while gravity suffices for unidirectional operation, optimizing the balance between simplicity and versatility.
Solution Approach 2:
The heat exchanger is designed to perform multiple functions: it can operate in gravity-aided mode for simple installations and in adverse gravity orientation with pump assistance for versatile applications. This multi-functionality allows the same device to adapt to different installation scenarios and operational requirements.
2Adaptability or versatility
If a pump is added to enable operation in adverse gravity orientation, then the heat exchanger can transfer heat in both directions, but the device complexity and cost increase
Solution Approach 1:
The system uses gravity to return condensed working fluid to the evaporator when operating in favorable orientation, eliminating the need for pump operation in that mode. The pump only activates when necessary for adverse gravity orientation, reducing overall system complexity and operational costs while maintaining versatility.
3Adaptability or versatility
If separate split coils with pump are used to overcome gravity limitation, then bidirectional heat transfer is enabled, but the system becomes more complex and expensive
Solution Approach 1:
The patent merges the evaporator and condenser sections into a single integrated heat exchanger unit with shared housing and working fluid circuit, rather than using separate split coils. This integration reduces system complexity and cost while the selective pump operation enables bidirectional heat transfer for seasonal adaptability.
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
Enables efficient heat transfer in both gravity-aided and adverse orientations, facilitating operation in multiple seasons by varying the direction of heat flow through the heat pipes, thereby enhancing the heat exchanger's performance and adaptability to changing ambient conditions.
Implementation Method 1
Multiple heat pipes extend between the upper header and the lower header. The heat pipes have first heat transfer sections proximate the upper header and second heat transfer sections proximate the lower header.
Implementation Method 2
a pumped two phase air to air heat exchanger
Implementation Method 3
a pump provided to return condensed liquid from the condenser to the evaporator when heat is being input to the upper fin section and removed from the lower fin section
Implementation Method 4
Known vertical air to air heat pipe heat exchangers rely on gravity to return the condensed working fluid from the condenser to the evaporator
Data Source
AI summary
A heat exchanger and method which is able to perform in different seasons. The heat exchanger has an upper header and a lower header. Multiple heat pipes extend between the upper header and the lower header, with each of the multiple heat pipes having an evaporator section at one end and a condenser section at the opposite end. The direction of heat flow through the multiple heat pipes is variable depending on ambient air conditions applied to the heat exchanger. A pump is provided in fluid communication with the upper header and the lower header. The pump operates when the heat exchanger is operating in a second mode in which the evaporator section is located above the condenser section, and the pump is disabled when the heat exchanger is operating in a first mode in which the condenser section is located above the evaporator section.