Thermostat Simulation

from tys import probe, progress

def simulate(cfg: dict):

    import simpy
    env = simpy.Environment()

    indoor_temp     = cfg["initial_temp"]       # indoor temp (°C)
    outside_temp    = cfg["outside_temp"]       # fixed outside temp
    setpoint        = cfg["setpoint"]           # desired indoor temp
    band            = cfg["comfort_band"]       # ±°C accepted dead-band
    loss_rate       = cfg["loss_coeff"]         # heat-loss constant
    heater_kw       = cfg["heater_power"]       # °C per tick when on
    control_gain    = cfg["gain"]               # controller aggressiveness
    sensor_delay    = cfg["sensor_delay"]       # perception delay (ticks)
    sim_time        = cfg["sim_time"]
    sensor_history  = [indoor_temp] * sensor_delay    # delay line for sensed temp
    heater_on       = False

    def recorder():
        while True:
            probe("indoor_temp", env.now, indoor_temp)
            probe("heater_on", env.now, 1 if heater_on else 0)
            yield env.timeout(0.5)
    env.process(recorder())

    done = env.event()

    def dynamics():
        nonlocal indoor_temp, heater_on
        for t in range(sim_time):
            sensor_T     = sensor_history[0]
            error        = setpoint - sensor_T
            heater_on    = error > control_gain * band        # bang-bang with gain

            heat_gain    = heater_kw if heater_on else 0
            heat_loss    = loss_rate * (indoor_temp - outside_temp)
            indoor_temp += heat_gain - heat_loss

            sensor_history.append(indoor_temp)
            sensor_history.pop(0)

            if abs(error) < band / 2 and t % 5 == 0:
                progress(int(100 * t / sim_time), "😌 In comfort zone")
            if abs(error) > 3 * band and heater_on:
                progress(int(100 * t / sim_time), "⚠︎ Big overshoot, heater still ON")

            yield env.timeout(1)

        progress(100)
        done.succeed({
            "final_temp": indoor_temp,
            "overshoot": max(sensor_history) - setpoint,
        })

    env.process(dynamics())
    env.run(until=done)
    return done.value


def requirements():
    return {
        "builtin": ["micropip", "pyyaml"],
        "external": ["simpy==4.1.1"],
    }