emrp:ws2025:agv
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| emrp:ws2025:agv [2026/02/28 19:32] – [5.3 Observations] 23553_students.hsrw | emrp:ws2025:agv [2026/02/28 22:52] (current) – [6. Discussion] 23553_students.hsrw | ||
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| === 4.5.2 Automations === | === 4.5.2 Automations === | ||
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| ===== 5. Testing & Validation ===== | ===== 5. Testing & Validation ===== | ||
| ==== 5.1 Test plan ==== | ==== 5.1 Test plan ==== | ||
| - | At the time of writing, the ventilation system could not be tested in the real greenhouse environment because a new greenhouse is currently under construction. Testing was therefore performed at home. While this limits realism, it enables a more controlled environment and repeatable test scenarios. The bathroom was chosen as the test environment because its volume of approximately 8 m³ is suitable for controlled ventilation experiments using one intake and one exhaust fan. This two-fan setup provides a comparable air exchange rate to the greenhouse design, because halving both the room volume (15 m³ → ~8 m³) and the number of fans (4 → 2) keeps the ventilation capacity per volume in a similar range under ideal conditions. In addition, temperature can be increased in a predictable way using a heater, and relative humidity can be raised quickly | + | At the time of writing, the ventilation system could not be tested in the real greenhouse environment because a new greenhouse is currently under construction. Testing was therefore performed at home. While this limits realism, it enables a more controlled environment and repeatable test scenarios. The bathroom was chosen as the test environment because its volume of approximately 8 m³ is suitable for controlled ventilation experiments using one intake and one exhaust fan. This two-fan setup provides a comparable air exchange rate to the greenhouse design, because halving both the room volume (15 m³ → ~8 m³) and the number of fans (4 → 2) keeps the ventilation capacity per volume in a similar range under ideal conditions. In addition, temperature can be increased in a predictable way using a 2kW heater, and relative humidity can be raised quickly (e.g., through shower steam). This makes it possible to evaluate the system by observing how temperature and humidity change when the fans are enabled. |
| Planned scenarios include: | Planned scenarios include: | ||
| * Sensor sanity check | * Sensor sanity check | ||
| - | * Hot-day / evening cooling | + | * Temperatur rise scenario |
| * stop heating when vent starts turn fans off (baseline) | * stop heating when vent starts turn fans off (baseline) | ||
| * stop heating when vent starts keep fans on | * stop heating when vent starts keep fans on | ||
| * keep heating when vent starts keep fans on | * keep heating when vent starts keep fans on | ||
| * Humidity rise scenario | * Humidity rise scenario | ||
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| ==== 5.2 Data collection and logging ==== | ==== 5.2 Data collection and logging ==== | ||
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| ==== 5.3 Observations ==== | ==== 5.3 Observations ==== | ||
| - | **Sensor sanity check:** | + | ==Sensor sanity check:== |
| When placed in the same environment, | When placed in the same environment, | ||
| + | ==Temperature rise scenario 1== | ||
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| + | In this scenario, the room was heated until the ventilation condition triggered (including the configured 1-minute stability delay). At that point, both the heater and the fans were turned off. The objective was to measure how long it takes for the indoor temperature to drop back below the “should vent” threshold without active ventilation (baseline cooling). | ||
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| + | Each run started from an initial indoor temperature of approximately 23.8 °C, and the test was repeated four times. | ||
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| + | Measured time to cool out of the “should vent” condition (heater OFF, fans OFF): | ||
| + | * Run 1: 3:50 min | ||
| + | * Run 2: 4:00 min | ||
| + | * Run 3: 4:20 min | ||
| + | * Run 4: 4:20 min | ||
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| + | The average time across all runs was 4:07 min, with a slight increasing trend over the repetitions (later runs took longer). | ||
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| + | ==Temperature rise scenario 2== | ||
| + | This scenario follows the same procedure as Scenario 1: the room is heated until the ventilation condition triggers (including the 1-minute stability delay). Once triggered, the heater is turned off. In contrast to Scenario 1, the fans remain on to actively cool the room back below the “should vent” threshold. | ||
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| + | The test was repeated three times. | ||
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| + | Measured time to cool out of the “should vent” condition (heater OFF, fans ON): | ||
| + | * Run 1: 3:50 min | ||
| + | * Run 2: 3:50 min | ||
| + | * Run 3: 3:50 min | ||
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| + | All three runs produced the same result, giving an average time of 3:50 min for this scenario. | ||
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| + | ==Temperature rise scenario 3== | ||
| + | With the 2000 W heater kept on, the fans were not able to cool the room back below the “should vent” threshold, but they likely slowed down the temperature increase. | ||
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| + | ==Humidity rise scenario:== | ||
| + | In this scenario, humidity was increased using hot water/steam until the automation triggered ventilation at 70% RH. Indoor humidity peaked at 88% RH and was then reduced to 63% RH while the fans were running. The fans stopped automatically after the humidity dropped back below the threshold (Fig 17. - 1.). After the fans stopped, indoor humidity began to rise again (Fig 17. - 2.). When the fans were started manually, humidity continued to decrease until the inside and outside humidity levels were approximately equal. During the final part of the test, the outside humidity increased (Fig 17. - 3.). | ||
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| + | ===== 6. Discussion ===== | ||
| + | The system successfully measured indoor/ | ||
| - | * Placeholder: | + | 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. |
| - | * Placeholder: | + | |
| - | * Placeholder: | + | |
| - | ===== 6. Results & Discussion ===== | + | 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. |
| - | ==== 6.1 Results | + | 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 ===== | ||
| - | ==== 6.2 Limitations ==== | + | This project demonstrates a working prototype of a Home Assistant–based greenhouse ventilation system using low-cost sensors and an ESP32 controller. The implementation covers the complete chain from sensing (inside/ |
| - | The current evaluation has several limitations: | + | ==== Outlook ==== |
| - | * Testing was performed in a bathroom rather than a real greenhouse, so airflow patterns, heat capacity, and leakage behavior differ significantly. | + | |
| - | * The controlled tests mainly covered cases where the “inside” environment was hotter and/or more humid than the “outside” reference. Conditions such as rain events, strong solar radiation, and rapid outside fluctuations were not fully represented. | + | |
| - | * DHT11 sensors are low accuracy, especially for humidity (often ±5% RH or worse with a range of 20-80%). | + | |
| - | ===== 7. Future Work Ideas ===== | + | The next step is the deployment |
| - | Here are a few ideas for future development, | + | * Additional sensing |
| - | * Add additional sensors | + | |
| * Soil moisture sensing | * Soil moisture sensing | ||
| * Light and CO₂ sensing for improved climate control decisions | * Light and CO₂ sensing for improved climate control decisions | ||
| - | * Extend | + | * Extended |
| * Automatic watering based on soil moisture and schedules | * Automatic watering based on soil moisture and schedules | ||
| - | * Artificial light | + | * Artificial |
| - | * Absolute humidity based ventilation decisions | + | * Active |
| - | * Add active | + | * Heater |
| - | * Heater/ | + | * Humidifier / dehumidifier system |
| - | * Humidifier / dehumidifier system | + | * Off-grid power system |
| - | * Off-grid power design outlook | + | * Battery/ |
| - | * Plan and implement a battery/ | + | * Power budgeting, |
| - | * Include power budgeting, safety (fusing), and autonomy targets (e.g., nights | + | |
| ===== 8. References / Sources ===== | ===== 8. References / Sources ===== | ||
emrp/ws2025/agv.1772303525.txt.gz · Last modified: 2026/02/28 19:32 by 23553_students.hsrw