Mixed Air Temperature Calculator
Calculate the temperature of mixed gases by composition or flow rate for thermal equilibrium and HVAC systems
Mixed Air Temperature Calculations
Calculation Method
Gas Composition Method
Calculate mixed temperature using: T = T₁ × P₁ + T₂ × P₂
Gas 1
Gas 2
Auto-calculated as (100 - P₁)
⚠️ Warning: Compositions must add up to 100%
Mixed Air Temperature Results
Enter gas properties to calculate mixed air temperature
Example Calculations
Gas Composition Example
Given: Two gases at different temperatures
Gas 1: 100°C at 30% composition
Gas 2: 20°C at 70% composition
Formula: T = T₁ × P₁ + T₂ × P₂
Solution: T = 100°C × 0.3 + 20°C × 0.7 = 44°C
HVAC System Example
Outside air: 30°C at 60 CFM
Return air: 23°C at 1,340 CFM
Total flow: 1,400 CFM
Supply air temperature: 23.3°C
Applications
HVAC Systems
Supply air temperature calculation
Gas Mixing
Industrial process temperature control
Thermal Equilibrium
Thermodynamics and heat transfer
Climate Control
Building environmental systems
Key Concepts
Thermal equilibrium and heat balance
Weighted average based on composition or flow
Conservation of energy principles
HVAC supply air temperature optimization
Zeroth law of thermodynamics
Understanding Mixed Air Temperature
What is Mixed Air Temperature?
Mixed air temperature is the final temperature achieved when two or more air streams or gases at different temperatures are combined and reach thermal equilibrium. The final temperature depends on the temperatures of the individual streams and their relative proportions.
Thermal Equilibrium Principle
- •Based on the Zeroth Law of Thermodynamics
- •Heat flows from higher to lower temperature
- •Final temperature is a weighted average
- •Conservation of energy applies
Calculation Methods
Gas Composition:
T = T₁ × P₁ + T₂ × P₂
HVAC Flow Rate:
Ts = (CFMoa × Toa + CFMra × Tra) / (CFMoa + CFMra)
Note: Both methods calculate a weighted average where the weights are either percentage compositions or flow rates.
HVAC Applications
Supply Air Temperature
The temperature of air delivered to conditioned spaces after mixing outside air with return air from the building.
Energy Efficiency
Optimizing the mix ratio helps reduce heating and cooling loads, improving overall system efficiency.
Indoor Air Quality
Proper mixing ensures adequate fresh air ventilation while maintaining comfortable temperature conditions.