important formulas for HVAC

 Here are some important formulas for HVAC (Heating, Ventilation, and Air Conditioning) systems:

1. Heat Transfer:

    - Q = UA × ΔT (Heat transfer rate = Overall heat transfer coefficient × Area × Temperature difference)

2. Cooling Load:

    - CL = Q / COP (Cooling load = Heat transfer rate / Coefficient of Performance)

3. Heating Load:

    - HL = Q / COP (Heating load = Heat transfer rate / Coefficient of Performance)

4. Airflow:

    - CFM = AV × SP (Cubic feet per minute = Air velocity × Supply pressure)

5. Duct Sizing:

    - D = √(CFM × 4000 / VP) (Duct diameter = Square root of (Cubic feet per minute × 4000 / Velocity pressure))

6. Psychrometrics:

    - RH = 100 × (PW / PS) (Relative humidity = 100 × (Partial pressure of water vapor / Saturation pressure))

    - TD = DB − (100 − RH) × (DB − WB) (Dew point temperature = Dry bulb temperature − (100 − Relative humidity) × (Dry bulb temperature − Wet bulb temperature))

7. Refrigeration:

    - TR = Q / COP (Tonnage rating = Cooling capacity / Coefficient of Performance)

    - COP = Q / (P × 3.412) (Coefficient of Performance = Cooling capacity / (Power input × 3.412))

8. Energy Efficiency:

    - SEER = (Q × 3.412) / (P × 24) (Seasonal Energy Efficiency Ratio = (Cooling capacity × 3.412) / (Power input × 24))

    - AFUE = (HU × 3.412) / (GI × 24) (Annual Fuel Utilization Efficiency = (Heating output × 3.412) / (Gas input × 24))

These formulas are essential for designing, sizing, and optimizing HVAC systems. However, it's important to note that the specific formulas and calculations may vary depending on the system type, location, and application.