Energy conservation, in SI units
C_air·dT_air/dt = Q_sun,air + Q_heater − U·A·(T_air−T_out) − ρ·c_p·(ACH·V/3600)·(T_air−T_out) − H·(T_air−T_soil) − L_v·E
C_soil·dT_soil/dt = Q_sun,soil + H·(T_air−T_soil) − K_ground·(T_soil−T_ground)
dm_v/dt = E − (ACH·V/3600)·(m_v/V − ρ_v,out), with condensation above saturation.
RH = 100·m_v / m_sat(T_air). Saturation vapour pressure is approximated by the Magnus formula; ideal vapour gas law gives saturation mass.
Assumptions and honest limits
Two well-mixed temperature nodes, uniform relative humidity and steady-volume ventilation; no CFD, plant physiology, detailed glass ray tracing, thermal radiation exchange or spatial microclimates. Soil is one effective reservoir. Rain modifies shell conductance by a small illustrative factor. Constant material parameters and approximate plant latent load. Thermostat uses ±0.35°C hysteresis. The graph's analytic reference is intentionally simpler than the live coupled model.
Envelope 310 m²; roof 145 m²; volume 700 m³; air density 1.20 kg/m³; air cₚ 1005 J/(kg·K); water latent heat 2.45 MJ/kg. Values are illustrative design assumptions, not measured greenhouse data.
Credits Procedural environment, original code and WebAudio synthesis. No external textures or audio files.