HVAC Calculation Logo
HVAC CalculationPowered by Solver360

Indoor Air Quality CO₂ Load Calculator

Back

Input Parameters

Unit System

CO₂ generation: 20 L/hr per person

Accounts for air mixing effectiveness

Ventilation Analysis

Predicted CO₂ Level

1,000
Indoor CO₂ ppm
Good
Rating

Ventilation Requirements

Minimum Outdoor Air245,242 CFM
Per Person24,524 CFM/person
Total System Airflow980,969 CFM
Outdoor Air %25 %

CO₂ Generation

Total Generation200 L/hr
Per Person20 L/hr

Standards Comparison

CO₂-based Requirement245,242 CFM
ASHRAE 62.1 Minimum150 CFM
Design Recommendation245,242 CFM

Air Quality Guidelines

Excellent (< 800 ppm)High air quality
Good (800-1000 ppm)Acceptable quality
Acceptable (1000-1400 ppm)May cause drowsiness
Poor (> 1400 ppm)Unacceptable quality

Design Notes

• Consider demand-controlled ventilation for variable occupancy
• CO₂ sensors should be placed in breathing zone
• Account for infiltration and natural ventilation

Ventilation Requirements Comparison

Detailed CO₂ & Indoor Air Quality Analysis

CO₂ Generation Analysis

Generation Rate:20 L/hr/person
Total Generation:200 L/hr
Mass Generation:0.40 kg/hr
Daily Generation:4.8 m³/day

Ventilation Effectiveness

Mixing Efficiency:80%
Air Change Rate:5885.8 ACH
Dilution Factor:2.5x
Removal Efficiency:100%

Energy & Cost Impact

Fan Power (est):77.2 kW
Heating Load (winter):1545.0 tons
Cooling Load (summer):441.4 tons
Annual Energy Cost:$81120

CO₂ Generation by Activity Level

Activity LevelCO₂ Rate (L/hr/person)Total GenerationRequired OA
sedentary15150 L/hr183,932 CFM
light20200 L/hr245,242 CFM
moderate35350 L/hr429,174 CFM
heavy50500 L/hr613,106 CFM

Demand Controlled Ventilation (DCV) Analysis

Energy Savings Potential
• Variable occupancy: 30-50% energy savings
• CO₂ sensor cost: $200-500 per zone
• Payback period: 2-4 years typical
• Best for spaces with variable occupancy
Implementation Notes
• Sensor placement: breathing zone (3-6 ft height)
• Control setpoint: 1000 ppm
• Minimum ventilation: 50 CFM
• Response time: 15-30 minutes typical

CO₂ Load Calculation Steps

1

Calculate Total CO₂ Generation

Formula:
GCO2=Npeople×RactivityG_{CO_2} = N_{people} \times R_{activity}
Calculation:
GCO2=10×20G_{CO_2} = 10 \times 20
Result:
200 L/hr200 \text{ L/hr}
2

Convert CO₂ Generation to CFM

Formula:
GCFM=GCO21.699G_{CFM} = \frac{G_{CO_2}}{1.699}
Calculation:
GCFM=2001.699G_{CFM} = \frac{200}{1.699}
Result:
117.7 CFM117.7 \text{ CFM}
3

Calculate CO₂-based Ventilation Requirement

Formula:
Vo=GCFM×106(Ci−Co)×EV_o = \frac{G_{CFM} \times 10^6}{(C_i - C_o) \times E}
Calculation:
Vo=117.7×106(1000−400)×0.8V_o = \frac{117.7 \times 10^6}{(1000 - 400) \times 0.8}
Result:
245242 CFM245242 \text{ CFM}
4

Calculate ASHRAE 62.1 Minimum

Formula:
VASHRAE=Npeople×15V_{ASHRAE} = N_{people} \times 15
Calculation:
VASHRAE=10×15V_{ASHRAE} = 10 \times 15
Result:
150 CFM150 \text{ CFM}
5

Determine Design Outdoor Air (higher of CO₂-based or ASHRAE)

Formula:
Vdesign=max⁡(Vo,VASHRAE)V_{design} = \max(V_o, V_{ASHRAE})
Calculation:
Vdesign=max⁡(245242,150)V_{design} = \max(245242, 150)
Result:
245242 CFM245242 \text{ CFM}
6

Calculate Total System Airflow (4× outdoor air for mixing)

Formula:
Qtotal=Vdesign×4Q_{total} = V_{design} \times 4
Calculation:
Qtotal=245242×4Q_{total} = 245242 \times 4
Result:
980969 CFM980969 \text{ CFM}
7

Calculate Predicted Indoor CO₂ Level

Formula:
Ci=Co+GCFM×106Vdesign×EC_i = C_o + \frac{G_{CFM} \times 10^6}{V_{design} \times E}
Calculation:
Ci=400+117.7×106245242×0.8C_i = 400 + \frac{117.7 \times 10^6}{245242 \times 0.8}
Result:
1000 ppm1000 \text{ ppm}