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--- emrp:ws2025:agv [2026/02/28 22:44] – 23553_students.hsrw
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 ===== 6. Discussion =====
-The system successfully measured indoor/outdoor temperature and humidity and controlled ventilation automatically via Home Assistant and ESPHome. In the controlled bathroom tests, the automation triggered reliably at the defined thresholds and the ventilation reduced both temperature and humidity when outside conditions were more favorable than inside.
+The system successfully measured indoor/outdoor temperature and humidity and controlled ventilation automatically via Home Assistant and ESPHome. In the controlled bathroom tests, the automation triggered reliably at the defined thresholds and ventilation reduced both temperature and humidity when outside conditions were more favorable than inside.
-In the temperature baseline test (heater OFF, fans OFF), cooling back below the ventilation threshold took 4:07 min on average. With ventilation enabled after switching the heater off (heater OFF, fans ON), cooling took 3:50 min across all runs. With a 2000 W heater kept ON, ventilation could not restore temperature below the threshold, but it likely slowed the temperature increase.
+One concern was the limited absolute accuracy of the DHT11 sensors, especially for relative humidity. However, the control logic primarily relies on relative comparisons between inside and outside rather than perfectly accurate absolute values. Using two identical sensor modules also helps because systematic offsets tend to cancel out when comparing trends and differences. As a result, the DHT11 accuracy is acceptable for this prototype, while higher accuracy sensors would improve confidence in the exact trigger thresholds.
-In the humidity test, ventilation started automatically at 70% RH. Indoor humidity peaked at 88% RH and was reduced to 63% RH while the fans were running. After the fans stopped, indoor humidity rose again. When started manually, ventilation continued reducing humidity until inside and outside humidity were approximately equal; increasing outside humidity towards the end reduced further dehumidification.
+In the temperature baseline test (heater OFF, fans OFF), cooling back below the ventilation threshold took 4:07 min on average. With ventilation enabled after switching the heater off (heater OFF, fans ON), cooling took 3:50 min across all runs. With a 2000 W heater kept ON, ventilation could not restore temperature below the threshold, but it likely slowed the temperature increase. The baseline cooldown duration increased over repeated trials (from 3:50 to 4:20), which is plausibly explained by heat storage in the room’s surfaces (walls, tiles, furniture) and their gradual release after the heater was switched off. The ventilation-enabled cooling test was performed after the baseline series, meaning it started under less favorable conditions; despite this, the cooldown time with fans remained lower (3:50), supporting a real cooling effect from ventilation in this setup.
-The temperature tests indicate that ventilation provides a measurable benefit once heat input is removed, but it cannot overcome strong continuous heating. In the baseline cooling runs without ventilation, the cooldown duration increased over repeated trials (from 3:50 to 4:20). A likely explanation is that, in addition to heating the air, the heater also warmed up the room’s surfaces (walls, tiles, furniture). As these surfaces store heat and release it back into the air after the heater is switched off, later runs can take longer to drop below the threshold.
-The ventilation-enabled cooling test (heater OFF, fans ON) was performed after the baseline test series, meaning it started from a room that had already accumulated additional heat in its surfaces. Even under these less favorable conditions, the cooldown time with fans remained lower (3:50), which supports that ventilation had a real, measurable cooling effect in this setup.
-The humidity test confirms that ventilation can effectively reduce indoor humidity when outside air is more favorable. Ventilation started automatically at 70% RH, reduced indoor humidity substantially, and then stopped once the threshold was passed. After the fans stopped, indoor humidity increased again even though no additional moisture was added, which suggests that without continued airflow some humid air pockets can remain and moisture on surfaces can re-equilibrate with the air. If humidity had climbed above 70% RH again, the automation would have restarted ventilation and continued reducing it. For the test, the fans were started manually instead, and indoor humidity kept dropping until it reached an equilibrium with the outside sensor reading. Towards the end, the measured outside humidity also increased slightly, which is most likely an artifact of the indoor test setup with limited fresh-air exchange rather than a realistic outdoor effect.
+In the humidity test, ventilation started automatically at 70% RH. Indoor humidity peaked at 88% RH and was reduced to 63% RH while the fans were running. After the fans stopped, indoor humidity rose again even though no additional moisture was added, suggesting that without continued airflow some humid air pockets can remain and moisture on surfaces can re-equilibrate with the air. If humidity had climbed above 70% RH again, the automation would have restarted ventilation. For this test, the fans were started manually instead, and indoor humidity continued to decrease until it approached equilibrium with the outside sensor reading. Towards the end, the measured outside humidity also increased slightly, which is most likely an artifact of the indoor test setup with limited fresh-air exchange rather than a realistic outdoor effect.
 ===== 7. Conclusion and outlook =====