Greenhouse Climate Control Simulator

Climate Controls

Heater power 40%

Roof vent opening 20%

Humidifier / misting 25%

Supplemental grow-light 30%

Simulation Speed

Air & Crop Readouts

Air temperature

22.0 °C

Relative humidity

55.0 %

Vapor pressure deficit

1.05 kPa

Photosynthesis rate

0 %

Crop growth: 0%Day 1

How it works

The greenhouse is a lumped-parameter energy and moisture balance driven by your controls plus an outdoor day/night cycle:

dT/dt  = [Q_solar + Q_heater − Q_loss − Q_transp] / C
Q_loss = U·(1 + vent·k_v)·(T_air − T_out)
T_out(t) = 15 + 8·sin(2π(t−6)/24)   [°C]

dRH/dt = [E_transp + E_humid − vent·k_h·(RH − RH_out)] / M

Photosynthesis follows a light-response curve (Michaelis–Menten), a Gaussian temperature-optimum curve around 25 °C, and a vapor-pressure-deficit stress term computed from the Tetens saturation-vapor-pressure formula:

SVP(T) = 0.6108 · exp(17.27·T / (T+237.3))   [kPa]
VPD    = SVP(T) · (1 − RH/100)

f_light = PAR / (PAR + I_k)
f_temp  = exp(−((T − 25) / 9)²)
f_vpd   = clamp(1 − max(0, VPD − 1.0)·0.6, 0, 1)

Growth rate = P_max · f_light · f_temp · f_vpd

Heater adds sensible heat, raising air temperature and (indirectly) lowering RH and VPD.
Vent opening exchanges greenhouse air with drier, more variable outside air — cools on hot days, dries the air, and speeds heat loss overnight.
Humidifier injects moisture directly, lowering VPD; too little and dry air stresses the crop, too much fights condensation.
Grow-light supplements sunlight after dusk and on cloudy passes, keeping photosynthesis running through the light-response curve.

The sweet spot for most greenhouse vegetables is roughly 22–27 °C air temperature and 0.4–1.2 kPa VPD — too dry (high VPD) closes plant stomata and halts photosynthesis, too humid (near-zero VPD) invites fungal disease and also slows transpiration-driven nutrient uptake.

Day 1 · 08:00

Heater Humidifier Grow-lights

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