Refrigeration Stop Valve Control for Rapid Evaporator Defrosting
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Solution Overview
Problem
Household refrigeration appliances face inefficiencies in energy use during defrosting due to pressure equalization between the condenser and evaporator when the compressor is off, leading to adiabatic cooling in the condenser and increased temperature in the evaporator, which hampers effective thermal energy release and cooling.
Innovation Solution
The solution involves opening the stop valve when the compressor is switched off to allow high-pressure refrigerant to flow into the evaporator for rapid defrosting, accompanied by an electric heater and a control unit that monitors temperature and icing conditions using sensors to optimize defrosting, potentially using a timer for time-controlled defrosting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the compressor is switched off for idle phases, then energy consumption is reduced, but pressure equalization between condenser and evaporator causes adiabatic cooling in the condenser and temperature rise in the evaporator, reducing thermal energy release efficiency
Solution Approach 1:
The stop valve is opened in advance during idle phases to allow warm high-pressure refrigerant to flow from the condenser to the evaporator before the next cooling cycle begins. This preliminary action pre-heats the evaporator and maintains condenser pressure, eliminating the need for energy-wasting re-cooling when the compressor restarts.
Solution Approach 2:
The patent converts the harmful effect of pressure equalization (which normally causes unwanted temperature changes) into a beneficial defrosting mechanism. By opening the stop valve during idle phases, the warm refrigerant flowing through the evaporator naturally melts ice buildup, turning a previously problematic thermal effect into a useful defrosting function that reduces energy consumption.
2Productivity
If the stop valve is opened during idle phases to enable defrosting, then evaporator defrosting efficiency is improved, but control complexity increases due to coordination between compressor switching and valve operation
Solution Approach 1:
The patent merges the defrosting function with the existing idle phase of the compressor operation. Instead of adding a separate defrosting cycle or control system, the stop valve is simply opened during the compressor's natural idle periods, combining two functions (idle recovery and defrosting) into one coordinated action, thereby minimizing control complexity while maximizing defrosting efficiency.
3Productivity
If high-pressure refrigerant flows into the evaporator during idle phases, then rapid defrosting is achieved, but pressure fluctuations may occur when the compressor restarts
Solution Approach 1:
The stop valve is opened during the idle phase before compressor restart to allow pressure equalization and defrosting to occur in advance. This preliminary pressure adjustment prevents sudden pressure fluctuations when the compressor重新启动, as the system is already in a balanced state, thereby maintaining reliability while achieving rapid defrosting.
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 enables energy-efficient defrosting by ensuring rapid heat input to the evaporator, maintaining cooling capacity and preventing undesired temperature rises, thus enhancing the overall efficiency and effectiveness of the refrigeration process.
Implementation Method 1
an evaporator, in which it cools down so much through expansion that it is able to dissipate heat take up a cold reservoir. The refrigerant evaporated as a result flows back to the compressor.
Implementation Method 2
The pressure drop in the condenser leads to adiabatic cooling there, so that the thermal energy contained in the refrigerant can no longer be released to the warm reservoir.
Implementation Method 3
a condenser, in which it gives off heat to a warm reservoir and condenses in the process
Implementation Method 4
a condenser, in which it gives off heat to a warm reservoir
Implementation Method 5
In order to further accelerate the defrosting process, an electric heater can be assigned to the evaporator.
Data Source
Figure 1
AI summary
A refrigeration machine for a domestic refrigerator comprises a compressor (1), a condenser (2) and an evaporator (5), which are connected to form a refrigerant circuit. A stop valve (3) is arranged in a refrigerant path from the condenser (2) to the evaporator (5).