EPA 608 Core · Refrigeration Fundamentals · Medium
Which of the following is a natural refrigerant?
Answer: B. R-744 (carbon dioxide).
- AR-134a (an HFC).
- BR-744 (carbon dioxide).✓ Correct
- CR-410A (an HFC blend).
- DR-1234yf (an HFO).
Why B is right
Carbon dioxide, ammonia, and propane are naturally occurring substances used as refrigerants.
More Core questions
- How is subcooling measured?
- What does superheat measure?
- When does a PT chart give the actual temperature of a refrigerant from its pressure?
- What does refrigerant do inside the evaporator?
- Which component raises the pressure and temperature of refrigerant vapor?
Go deeper with the study guide EPA 608 Core Exam: Study Guide for 2026, try the free 10-question test or browse all EPA 608 practice questions.
A practice question written for study, checked against 40 CFR Part 82, Subpart F. It is not an official EPA exam question, and this site is not affiliated with the U.S. EPA.