Heat Pump Sub-Cooling Heat Transfer for Evaporator Frost Prevention
Solution Overview
Problem
Existing heat pump systems face challenges in preventing evaporator frosting during sub-cooling processes, leading to reduced performance and potential component failure, as conventional defrosting methods interrupt normal heating operations and require external energy or complex refrigerant circulation mechanisms.
Innovation Solution
A heat pump design that utilizes heat released during the sub-cooling process to maintain the evaporator's surface temperature above freezing without external energy input, employing a refrigerant circuit with sub-cooling means and heat transfer means, such as meandering pipes or heat pipes, to efficiently transport heat from the sub-cooling process to the evaporator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional defrosting operations are performed separately from normal heating operation, then the evaporator can be defrosted, but the normal heating operation is interrupted and additional energy input is required
Solution Approach 1:
The patent merges the defrosting function with the normal heating operation by using the sub-cooling heat exchanger to transfer heat to the evaporator continuously during both operations. This eliminates the need for separate defrosting cycles and maintains uninterrupted heating performance while preventing evaporator frosting.
Solution Approach 2:
The system uses its own sub-cooling process heat to defrost the evaporator, rather than requiring external energy input. The waste heat from refrigerant sub-cooling is utilized to maintain evaporator temperature above freezing point, making the defrosting process self-sufficient and energy-efficient.
2Use of energy by moving object
If passive defrost system using thermosyphon loop is used, then no external energy input is required, but refrigerant circulation depends on gravity effect and proper positioning is required
Solution Approach 1:
The patent replaces the passive thermosyphon loop mechanism with an active heat transfer system using the sub-cooling heat exchanger. This allows controlled refrigerant circulation without relying on gravity-driven natural convection, eliminating the need for specific component positioning while still avoiding external energy input for defrosting.
3Ease of operation
If active defrost system with refrigerant pump is used, then refrigerant can be circulated from storage module to evaporator, but external energy input is required and pump design is complex
Solution Approach 1:
The system utilizes the refrigerant's own pressure and the sub-cooling heat exchanger to achieve controlled circulation to the evaporator, eliminating the need for an additional refrigerant pump. The high-pressure refrigerant naturally flows through the sub-cooling heat exchanger, providing both circulation control and heat transfer without external energy consumption.
4Reliability
If additional heat exchanger is added for preheating ambient air, then frost prevention is achieved, but pressure drop on evaporator increases and fan capacity requirement increases
Solution Approach 1:
The sub-cooling heat exchanger serves dual functions: it cools the refrigerant during the sub-cooling process and simultaneously heats the evaporator to prevent frosting. This eliminates the need for a separate preheating heat exchanger, reducing system complexity and avoiding additional pressure drop that would require higher fan capacity.
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 allows for continuous frost prevention during normal operation without interrupting heating, enhancing the heat pump's efficiency and maintaining the evaporator surface clear of frost and ice, with improved reliability and reduced energy consumption.
Implementation Method 1
heat transfer means arranged to transfer heat released from the refrigerant in the sub-cooling process from the sub-cooling means to the evaporator
Implementation Method 2
an evaporator... where the refrigerant can evaporate. This can cause the refrigeration effect, because a supply of energy to the refrigerant is needed in order for the process of evaporation to occur
Implementation Method 3
a condenser... where the refrigerant can be condensed and liquefied by cooling down the refrigerant. Heat is released in the process of condensing
Data Source
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AI summary
An anti-frost heat pump according to the present invention is capable of preventing an evaporator from frosting during a sub-cooling process by using heat released in the sub-cooling process in sub-cooling means. The heat pump includes a refrigerant circuit having an evaporator, a condenser, sub-cooling means arranged to perform a sub-cooling process of cooling a refrigerant flowing out of the condenser, and heat transfer means arranged to transfer heat released from the refrigerant in the sub-cooling process from the sub-cooling means to the evaporator during the sub-cooling process. A method of defrosting according to the present invention includes a sub-cooling step of performing a sub-cooling process of cooling a refrigerant flowing out of the condenser, and a heat transfer step of transferring heat released from the refrigerant in the sub-cooling process of the sub-cooling step to the evaporator during the sub-cooling process.