What temperature do combustion gases drop to when passed through a secondary exchanger?

When combustion gases pass through a secondary heat exchanger, they typically experience a temperature reduction as the heat is transferred away from the gases to a secondary medium, often water or air. The temperature to which the gases cool down depends on several factors, including the efficiency of the heat exchanger, the flow rate of the gases, and the temperature of the medium absorbing the heat.

In this scenario, a drop to 65°C (150°F) is a reasonable expectation for well-designed secondary heat exchangers in various applications. Such an efficient cooling process allows for effective heat recovery, which can be crucial for improving overall system efficiency and reducing emissions. These factors contribute to this temperature being a common target in industrial settings, where maximizing heat recovery is critical for energy conservation and operational efficiency.

Other temperature options may not align with typical operational practices or the efficiency expected from a secondary exchanger, making 65°C the most fitting choice in this context.