Air Conditioner Compressor Interlock for Flammable Refrigerant Safety
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Solution Overview
Problem
Existing air conditioners using flammable refrigerants lack adequate safety measures to prevent the formation of flammable regions in case of refrigerant leakage.
Innovation Solution
The air conditioner controls the compressor to start only when the indoor fan's rotational frequency exceeds a predetermined level, ensuring sufficient airflow to prevent the formation of flammable regions by using a flammable refrigerant, and incorporates safety shutoff valves and an auxiliary power supply to manage refrigerant leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the compressor is allowed to start regardless of indoor fan speed, then the cooling/heating performance is maintained, but flammable refrigerant can accumulate and form explosive regions
Solution Approach 1:
The control unit prevents the compressor from starting when the indoor fan rotational frequency is below the predetermined threshold, proactively avoiding the creation of flammable regions before they can form. This preliminary protective action blocks the harmful sequence at its origin by ensuring adequate airflow is present before refrigerant compression begins.
Solution Approach 2:
The system establishes a preliminary condition (indoor fan speed above threshold) that must be satisfied before allowing compressor operation. This preliminary check ensures that sufficient airflow is guaranteed before any refrigerant could potentially leak and accumulate, preventing dangerous conditions from developing.
2Reliability
If the indoor fan rotational frequency is not monitored, then the device complexity is reduced, but flammable regions can form undetected
Solution Approach 1:
The control unit continuously monitors the rotational frequency of the indoor fan and uses this feedback information to determine whether compressor startup is safe. This feedback mechanism enables real-time safety assessment without requiring complex additional sensing systems, as it leverages existing operational data.
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 effectively minimizes the formation of flammable regions by ensuring sufficient airflow and reducing refrigerant outflow, even during power failures, thereby enhancing safety in air conditioners using flammable refrigerants.
Implementation Method 1
ensuring sufficient airflow can be ensured, and the air inside of the air-conditioned space can be sufficiently stirred
Implementation Method 2
an outdoor unit that includes a compressor
Implementation Method 3
an outdoor heat exchanger, an indoor heat exchanger
Data Source
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Figure 3
AI summary
An air conditioner includes: an outdoor unit that includes a compressor, an outdoor heat exchanger, an outdoor fan, and an expansion mechanism; and an indoor unit that includes an indoor heat exchanger and an indoor fan. The outdoor unit and the indoor unit together form a refrigeration cycle circuit by being connected by a refrigerant pipe. The refrigeration cycle circuit uses a flammable refrigerant, and the compressor is controlled not to start when a driving rotational frequency of the indoor fan is lower than or equal to a predetermined rotational frequency.