Energy Conversion Guide
Energy is the capacity to do work, appearing in virtually every engineering discipline. The SI unit is the joule (J), where 1 J = 1 N·m = 1 W·s. Energy comes in many forms: mechanical, thermal, electrical, and chemical.
Key conversions: 1 kWh = 3,600,000 J = 3,412.14 BTU, 1 BTU = 1,055.06 J, 1 kcal = 4,186.8 J, 1 therm = 100,000 BTU = 105.506 MJ, 1 MMBtu = 1,055.06 MJ, 1 eV = 1.602 × 10⁻¹⁹ J.
Energy conversion is central to power generation, HVAC system design, chemical process engineering, fuel comparison, building energy audits, and renewable energy analysis. Utility billing uses kWh (electricity) and therms or MMBtu (natural gas).
Common pitfalls: confusing energy (kWh) with power (kW), misinterpreting MM as an SI mega prefix instead of the Roman numeral million convention, mixing up food Calories (kcal) with physics calories (cal), and assuming all BTU definitions are identical (BTU_IT vs BTU_th differ by ~0.07%).