Cooling system for low temperature storage
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Solution Overview
Problem
Conventional cooling systems for low temperature storage face issues such as increased energy costs, temperature fluctuations, and frequent heater failures during defrosting operations, which affect food freshness and maintenance costs.
Innovation Solution
A cooling system that utilizes hot gas for defrosting a first evaporator and simultaneously performs defrosting and cooling operations by expanding and evaporating condensed refrigerant in a second evaporator, while using a bypass pipe to direct refrigerant through an outdoor heat exchanger, allowing it to function as an evaporator and harness heat from outdoor air.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an electric heater is used for defrosting the evaporator, then the frost can be removed, but the energy consumption increases and the cost increases
Solution Approach 1:
The system uses the refrigerant itself to perform the defrosting operation. The refrigerant is diverted to the evaporator where it absorbs heat from the frost, melting it and draining away. This self-service approach eliminates the need for external electric heaters and reduces energy consumption.
Solution Approach 2:
The system discards the conventional electric heater approach and recovers heat from the refrigerant cycle. By redirecting refrigerant flow through the evaporator during defrost mode, the system recovers thermal energy that would otherwise be wasted, using it to melt frost without additional energy input.
2Reliability
If the cooling operation through the evaporator is stopped during heater defrosting, then the defrosting can be performed, but the temperature of the storage is raised and the freshness of food is lowered
Solution Approach 1:
The system implements periodic defrosting cycles where the refrigerant flow is temporarily redirected to the evaporator for defrosting, then returned to normal cooling operation. This periodic switching allows defrosting to occur without requiring continuous cessation of cooling, maintaining overall temperature stability.
Solution Approach 2:
The evaporator serves dual functions: normal cooling mode and defrosting mode. By controlling refrigerant flow direction, the same component performs both cooling and defrosting operations, eliminating the need for separate heating elements and allowing seamless transition between functions to maintain storage temperature.
3Reliability
If an electric heater is installed for defrosting, then the defrosting function is provided, but the replacement or repair cost increases due to frequent failure
Solution Approach 1:
The system extracts and removes the electric heater component from the defrosting system. By eliminating the heater entirely and using refrigerant-based defrosting instead, the system removes the source of frequent failures and high maintenance costs associated with electric heating elements.
Solution Approach 2:
The refrigerant-based defrosting system is self-regulating and requires no active control or maintenance of heating elements. The refrigerant automatically absorbs heat from frost and melts it, providing a maintenance-free defrosting solution compared to electric heaters that require monitoring, control, and periodic replacement.
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 approach reduces defrosting time and energy consumption, allows simultaneous defrosting and cooling operations, and improves efficiency by using outdoor air heat for defrosting, minimizing temperature fluctuations and maintenance costs.
Implementation Method 1
obtain an amount of heat required for defrosting from an outdoor air heat source
Implementation Method 2
a first evaporator into which a refrigerant flowing through the first bypass pipe is introduced to perform defrost
Implementation Method 3
a second evaporator disposed at an outlet side of the first evaporator to evaporate a refrigerant passing through the first evaporator
Data Source
AI summary
The present invention relates to a cooling system for a low temperature storage. The cooling system for the low temperature storage according to an embodiment of the present invention comprises: a first outdoor valve disposed between a compressor and an outdoor heat exchanger and selectively restricting an inflow of a refrigerant into the outdoor heat exchanger; and a first bypass pipe branched from an inlet side of the first outdoor valve and guiding the refrigerant to bypass the outdoor heat exchanger, so that the refrigerant can be guided to bypass the outdoor heat exchanger during defrosting operation of the cooling system.