Single-Cycle Refrigerator Control for Low-Ambient Dual Cooling
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Solution Overview
Problem
Single-circuit refrigeration devices struggle to efficiently cool both compartments, especially when ambient temperatures are low, leading to insufficient cooling of the colder compartment and increased energy consumption due to the need for precise parameter matching and additional heating in warmer compartments.
Innovation Solution
Implementing a control circuit that switches the compressor on after an extended standstill based on a time limit, eliminating the need for a temperature sensor in the colder compartment, and using a second temperature sensor on the warm compartment to detect refrigerant arrival for efficient cooling distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-circuit refrigeration device operates with a temperature sensor only in the warmer compartment, then the device structure is simple and inexpensive, but the colder compartment receives insufficient cooling when ambient temperature is low
Solution Approach 1:
The patent introduces a timer as an intermediary device to mediate between the single temperature sensor in the warmer compartment and the compressor control. The timer measures compressor runtime and triggers supplemental cooling cycles when the warmer compartment has been cooled sufficiently, allowing indirect control to benefit the colder compartment without requiring direct temperature measurement there.
Solution Approach 2:
The system performs preliminary cooling of the warmer compartment first, then uses timer-based control to initiate additional compressor operation while the warmer compartment temperature is already acceptable. This preliminary action approach ensures the colder compartment receives adequate cooling during the supplemental runtime without unnecessarily cooling the warmer compartment further.
2Reliability
If the compressor runtime is extended to ensure sufficient cooling of the colder compartment, then the colder compartment receives adequate cooling, but energy consumption increases
Solution Approach 1:
The system uses feedback from the temperature sensor in the warmer compartment to control compressor operation. When the warmer compartment reaches the target temperature, the timer stops additional compressor runtime. This feedback mechanism prevents excessive energy consumption by limiting supplemental cooling only to what is necessary for the colder compartment.
Solution Approach 2:
The patent applies partial action by providing exactly the amount of additional cooling needed for the colder compartment through timer-controlled supplemental runtime, rather than continuous or excessive cooling. The timer calculates the precise additional runtime required based on the cooler compartment's volume and thermal characteristics.
3Reliability
If a second temperature sensor is installed in the colder compartment to directly control cooling, then the colder compartment cooling is optimized, but production costs increase
Solution Approach 1:
The patent creates a functional copy of temperature sensing capability through the timer mechanism. Instead of physically installing a second temperature sensor in the colder compartment, the timer replicates the control function by calculating required cooling duration based on the cooler compartment's characteristics, achieving similar control效果 without the additional hardware cost.
4Reliability
If the evaporator dimensions and refrigerant mass flow are precisely matched, then the single-circuit system can cool both compartments adequately, but the system becomes sensitive to ambient temperature variations
Solution Approach 1:
The patent introduces dynamic adaptability through the timer-based control system. The timer can adjust supplemental compressor runtime based on ambient conditions and actual cooling needs, making the system adaptable to various ambient temperatures. This dynamic adjustment capability allows the system to maintain reliable cooling performance across a wider range of ambient temperatures than fixed-parameter single-circuit designs.
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
Ensures sufficient cooling of the colder compartment without direct temperature measurement, reducing production costs and energy inefficiencies by optimizing compressor operation based on ambient conditions.
Implementation Method 1
a compressor (8) connected to at least two evaporators (6, 7)
Implementation Method 2
at least two evaporators (6, 7), which are each assigned to storage compartments (2, 3) with different temperatures
Implementation Method 3
the evaporators (6, 7), together with a compressor (8), a condenser (9), a throttle point (17)
Implementation Method 4
a throttle point (17) between the condenser (9) and the first evaporator (6)
Data Source
Figure 1~2
Figure 3~4
AI summary
A refrigeration appliance, in particular a household refrigeration appliance, includes a refrigerant cycle in which a compressor (8) is connected to at least one first evaporator (6) associated with a cold storage compartment (2) and to a second evaporator (7) which is serially connected downstream of the first evaporator (6) and is associated with a warm storage compartment (3). A control circuit (12) is connected to a first temperature sensor (13) of the warm storage compartment (3) in order to switch on the compressor (8) when the temperature (T; T1) detected by the first temperature sensor (13) exceeds a maximum value (Tmax) and when the time since the compressor (8) was last switched off exceeds a maximum value (taus).