Question

Factors affecting furnace efficiency do not include:

• A. Type of fuel used
• B. Design of the furnace
• C. Ambient temperature
• D. Color of the furnace exterior

Hint:

Focus on operational and thermodynamic factors like design, fuel, and heat losses when evaluating furnace efficiency—not cosmetic attributes like exterior color.

Answer 1

The Correct Option is D

Step 1: Furnace efficiency refers to how effectively a furnace converts the energy in fuel into usable heat for the process or environment being heated. Several technical factors influence this efficiency. 
Step 2: These factors include:

• The type of fuel used — different fuels have different calorific values and combustion characteristics.
• The design of the furnace — including insulation, burner placement, and heat recovery mechanisms.
• The ambient temperature — this affects heat losses from the system and preheating requirements.

Step 3: The color of the furnace exterior does not significantly affect the internal thermal efficiency of the system, as it has negligible impact on heat retention or transfer within the high-temperature environment of a furnace. 
Hence, it is not considered a factor influencing furnace efficiency.