What it does
A calculator that estimates heating, cooling, dehumidification and lighting loads, plant transpiration, and daily operating costs for a controlled-environment space.
When to use it
Use it to see how room size, insulation, ventilation, setpoints and plant load affect energy use and moisture removal.
How it calculates
- Ventilation gain = (outdoor − target temp) × volume × ACH × 1.2 kg/m³ × 1005 J/kg·K ÷ 3600; envelope gain uses floor area × 6 and U = (1 − insulation factor) × 5 W/m²·K
- Lighting heat = 85% of lighting load; transpiration = plants × crop rate (L/plant/day) ÷ operating hours
- Moisture load converted to power at 2450 kJ/kg; absolute humidity = 621.98·e ÷ (101.325 − e) g/kg
- Costs at $0.12/kWh and $0.003/L; carbon footprint at 0.5 kg CO₂/kWh. Without cached outdoor weather it assumes 15 °C and 50% RH outside
What you enter
- Floor Area(m²)
- Ceiling Height(m)
- Insulation Quality(poor, average, good, excellent)
- Ventilation Rate(ACH)
- Target Temperature(°C)
- Target Humidity(%)
- Target CO₂(ppm)
- Operating Hours/Day
- Crop Type and Growth Stage
- Plant density (plants/m²) and lighting load (W)
What you get
- Total Energy(kW)
- Transpiration(L/hr)
- Daily Cost($)
- Heating, Cooling and Dehumidification Load(kW)
- Energy Efficiency(kWh/kg)
- Water Efficiency(L/kg)
- Carbon Footprint(kg CO₂/day)
- Daily Energy and Water Cost($)