MACS 609 Certification Practice Exam

What was a significant design change for HFC-134a A/C systems compared to CFC-12 A/C systems?

1. Decreased condenser size

2. Increased condenser capacity and airflow

3. The elimination of evaporators

4. Reduction in compressor size

The correct answer is: Increased condenser capacity and airflow

The significant design change for HFC-134a A/C systems compared to CFC-12 A/C systems is an increased condenser capacity and airflow. HFC-134a has different thermodynamic properties than CFC-12, leading to a need for adjustments in the system design for optimal performance. This switch to HFC-134a requires that the condenser be larger to efficiently reject heat, ensuring that the refrigerant can properly condense. The increased capacity allows for better heat exchange, which is critical for the A/C system's effectiveness, particularly under varying operating conditions. Additionally, increased airflow through the condenser is essential to maintain performance and efficiency, as it helps in cooling the refrigerant effectively. Overall, these modifications are vital for adapting to the properties of HFC-134a, ensuring that the air conditioning system operates effectively while complying with environmental regulations stemming from the phase-out of CFCs.