What do the special slide-rule calculator and CO2 indicator measure?

The special slide-rule calculator and CO2 indicator are tools commonly used in combustion analysis. They are primarily designed to measure combustion efficiency and stack loss. The slide-rule calculator allows technicians to quickly determine the efficiency of the combustion process by comparing the amount of fuel consumed to the amount of useful energy produced, while the CO2 indicator measures the concentration of carbon dioxide in the flue gases, which is an essential factor in assessing how well the combustion process is functioning.

When combustion is efficient, a higher percentage of fuel is converted into usable energy, and the emissions, including CO2, are ideally minimized. Conversely, stack loss indicates how much energy is escaping through the exhaust system, which is a critical component of overall system efficiency. Thus, both tools provide valuable insights that help technicians optimize performance and reduce waste in combustion systems.

The other options pertain to different measurements not related to the focus of the slide-rule calculator and CO2 indicator. For instance, flue gas temperature and pressure relate to the immediate physical conditions of the exhaust, air flow rates and humidity are relevant in HVAC and aerodynamics, and refrigerant efficiency and leakage deal specifically with refrigeration systems and not combustion analysis.