Which statement about belt-driven compressors is true?

The statement that some hybrids use combined belt/electric compressors is true because hybrid systems often integrate multiple forms of power to improve efficiency and performance. In the context of HVAC systems, a belt-driven compressor can work in tandem with an electric motor, allowing for better fuel efficiency and adaptability to varying load conditions. This combination enables the system to utilize the strengths of both belt-driven and electric components, making it versatile and effective in a range of applications.

Belt-driven compressors are not inherently hybrids; they are a type of compressor that can operate with mechanical input. Therefore, not all belt-driven compressors fall under the hybrid category. Moreover, the existence of belt-driven compressors is well established in mechanical and HVAC technology, so the assertion that they do not exist would be incorrect. Similarly, stating that all compressors use electric only overlooks various compressor designs and their operational modes, including those that utilize belt-driven mechanisms.