Temperature Control System with Heater-Based Liquid Back Prevention
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Solution Overview
Problem
Existing temperature control systems are bulky due to the inclusion of a large accumulator, which hinders compactness and ease of transportation, and struggle with refrigerant liquid back issues when using a reduced or no accumulator.
Innovation Solution
A temperature control system design that omits the accumulator and incorporates a heater in the fluid circulation apparatus, with a control apparatus that calculates and adjusts the heating capacity based on specific heat and flow rate to prevent refrigerant liquid back by maintaining the fluid temperature within a target range, ensuring the refrigerant remains superheated vapor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an accumulator is used in the refrigeration apparatus to prevent liquid back, then refrigerant liquid back is suppressed, but the system size increases and compactness is reduced
Solution Approach 1:
The invention extracts the liquid back prevention function from the accumulator and relocates it to the expansion valve through specific valve operations. The expansion valve is controlled to maintain evaporator outlet superheat, thereby preventing liquid back without requiring a large accumulator, thus reducing system size while maintaining reliability
Solution Approach 2:
The expansion valve is given multiple functions: it not only controls refrigerant flow rate but also maintains evaporator outlet superheat to prevent liquid back. This multi-functionality eliminates the need for a separate accumulator, reducing system size while maintaining liquid back prevention capability
2Volume of moving object
If the accumulator capacity is reduced to decrease system size, then compactness is improved, but liquid back suppression capability deteriorates
Solution Approach 1:
The invention implements feedback control by monitoring evaporator outlet temperature and pressure to calculate superheat, and adjusting expansion valve opening accordingly. This feedback mechanism ensures liquid back prevention even with reduced accumulator capacity by actively maintaining proper refrigerant state
Solution Approach 2:
The system performs preliminary heating of the evaporator outlet refrigerant using a heater when liquid back risk is detected. This preliminary action prevents liquid back by ensuring refrigerant is fully vaporized before entering the compressor, compensating for the reduced accumulator capacity
3Volume of moving object
If no accumulator is used to achieve maximum compactness, then system size is minimized, but liquid back prevention capability is lost
Solution Approach 1:
The invention completely removes the accumulator from the system and extracts its liquid back prevention function to the expansion valve and evaporator outlet heating system. The expansion valve is controlled to maintain superheat, and a heater provides additional protection, achieving liquid back prevention without any accumulator
Solution Approach 2:
The invention introduces a heater as an intermediary device at the evaporator outlet to prevent liquid back. When liquid back risk is detected, the heater heats the refrigerant to ensure it is fully vaporized before entering the compressor, compensating for the complete absence of an accumulator
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 design effectively suppresses refrigerant liquid back, even with a reduced accumulator or none, allowing for a more compact system by maintaining the refrigerant in a superheated state and preventing evaporation inefficiencies.
Implementation Method 1
a heater at a position downstream of the temperature control object and upstream of the evaporator
Implementation Method 2
the control apparatus activates the heater to heat the fluid by the heater
Implementation Method 3
a refrigeration apparatus having a compressor, a condenser, an expansion valve and an evaporator are connected in this order for circulating a refrigerant
Implementation Method 4
the fluid circulated by the fluid circulation apparatus is cooled by the evaporator of the refrigeration apparatus
Data Source
AI summary
A temperature control system according to one embodiment includes: a refrigeration apparatus in which a compressor, a condenser, an expansion valve and an evaporator are connected in this order for circulating a refrigerant; a fluid circulation apparatus that causes a fluid to be heat-exchanged in the evaporator, then sends the fluid to a temperature control object, and again causes the fluid having passed through the temperature control object to be heat-exchanged in the evaporator, the fluid circulation apparatus having a heater at a position downstream of the temperature control object and upstream of the evaporator; and a control apparatus. The control apparatus activates the heater to heat the fluid by the heater, when the fluid circulation apparatus has become in a no-load operation state or a no-load-operation transition operation state, wherein the no-load operation state is a state in which the fluid and the temperature control object do not heat-exchange, the no-load-operation transition operation state is a state that is in transition to the no-load operation state.