Refrigerator Temperature Threshold Control for Faster Food Cooling
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Solution Overview
Problem
Existing refrigerators and freezers take a long time to cool newly introduced goods, leading to potential quality impairments, especially for fresh items.
Innovation Solution
A control device that lowers the lower temperature threshold value temporarily upon detecting goods introduction, increasing cooling capacity by switching to a second setpoint temperature range with a reduced lower threshold, while maintaining the upper threshold constant, and using sensors to generate a goods insertion signal based on door opening or compressor runtime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the temperature is regulated to a standard setpoint range (4°C to 6°C) in normal operation, then the refrigerator maintains stable temperature for stored goods, but the cooling speed for newly introduced goods is too slow
Solution Approach 1:
The control device dynamically adjusts the lower temperature threshold value based on operational conditions. In normal operation, it maintains a standard threshold for temperature stability, but when goods are introduced (detected via door opening duration or compressor runtime), it temporarily lowers the threshold to accelerate cooling, then restores it afterward. This dynamic adjustment resolves the contradiction between cooling speed and temperature stability.
Solution Approach 2:
The invention changes the temperature control parameter (lower threshold value) from a fixed setting to a variable one. By temporarily reducing the lower threshold value from the normal range (e.g., from 4°C to a lower value) when goods are introduced, the system increases the temperature difference driving force for heat transfer, thereby accelerating cooling without permanently compromising temperature stability.
2Productivity
If the lower temperature threshold value is lowered to accelerate cooling of introduced goods, then cooling capacity increases, but the temperature may drop too close to the freezing point
Solution Approach 1:
The system applies periodic action by temporarily lowering the lower threshold value only during the period when goods are being introduced and need rapid cooling. The control device detects goods introduction (via door opening sensor or compressor runtime monitoring) and activates the lowered threshold mode for a predetermined time or until cooling is sufficient, then returns to normal operation. This periodic adjustment provides high cooling capacity when needed while avoiding excessive temperature drops.
3Productivity
If the upper temperature threshold value is also lowered along with the lower threshold, then cooling capacity increases further, but the temperature control range becomes too narrow and may cause unnecessary compressor cycling
Solution Approach 1:
The invention applies local quality by adjusting only the lower threshold value while keeping the upper threshold value constant during goods introduction. This creates an asymmetric adjustment that expands the effective temperature control range on the lower side (enhancing cooling capacity) while maintaining the upper boundary to prevent excessive compressor cycling. The selective adjustment of only one threshold parameter optimizes cooling performance without over-complicating the control logic.
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 accelerates cooling, reducing the time to reach a lower temperature level after goods are placed inside, thereby preserving food quality.
Implementation Method 1
a refrigerant circuit with a compressor (5), a condenser, an expansion element (7) and an evaporator (9)
Data Source
Figure 1
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Figure 3
AI summary
The invention relates to a cooler and/or freezer comprising a control device (10) for regulating an actual temperature (Tist) in a cooling compartment (1) between an upper and a lower temperature threshold (T1, T2). Upon the existence of a goods placement signal (Sw) indicating the placement of goods for cooling into the cooling compartment (1), the lower temperature threshold (T1) is lowered for a pre-determined time period (?t0).