EPRI Heat Transfer & Fluid Flow Practice Test 2026 - Free Practice Questions and Study Guide for Heat Transfer & Fluid Flow Certification

The main idea is that cycle efficiency improves when the back pressure on the turbine is reduced. Increasing condenser vacuum lowers the condenser pressure, allowing the steam to expand more in the turbine. That bigger expansion produces more turbine work without needing more heat input from the boiler, so the net work rises while the heat added stays about the same. With a larger net work for roughly the same heat input, the efficiency goes up. In practice, this gain holds up to practical limits where pumping or condenser requirements don’t offset the benefit.