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report [2025/06/16 10:51] – team4report [2025/07/01 13:51] (current) – [Abstract] team4
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 ===== Abstract ===== ===== Abstract =====
  
 +The European Project Semester (EPS) is an innovative engineering capstone project semester. Currently, the programme is offered by 20 European universities, including the Instituto Superior de Engenharia do Porto (ISEP). EPS employs a learning framework based on real-world challenges, interdisciplinary projects, and multicultural and multidisciplinary teamwork. Teams are required to design solutions based on market and state-of-the-art analyses, adhere to ethical and sustainability principles, and develop and test a proof-of-concept prototype. In the spring of 2025, an EPS@ISEP team decided to address the issue of domestic water waste.  The most apparent waste occurs when users turn on the tap and wait for the water to heat up, sending clean water down the drain. The designed solution eliminates this waste by redirecting water below the temperature set by the user from the shower to an additional toilet water tank. AzuLoop consists of a smart shower mixer, a water tank that adapts to existing toilet water tanks, and a few additional pipes. AzuLoop is easy to install, provides a comfortable shower experience, and reuses the clean cold shower water. 
 +During the semester, the team successfully designed, developed, and tested the AzuLoop prototype, while gaining valuable technical and personal skills through collaborative learning
 ===== Glossary ===== ===== Glossary =====
 <WRAP round box 400px> <WRAP round box 400px>
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 Customer Service: Customer Service:
-  * Offering a 24/7 chatbot and consultations during office hours to answer customer questions and build trust.+  * Offering a 24/7 chat for consultations during office hours to answer customer questions and build trust with a specialist.
  
  
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 -Risk identification during design -Risk identification during design
- 
--Compliance with relevant EU standards(CE marking, water safety and hygiene, electrical safety) 
  
 -Clear documentation and user guidance -Clear documentation and user guidance
  
 +-Compliance with relevant EU directives, such as the Low Voltage Directive (2014/35/EU) for electrical safety, the EMC Directive (2014/30/EU) for signal interference protection, the Machinery Directive (2006/42/EC) for automation safety, the Drinking Water Directive ((EU) 2020/2184) for hygiene in water systems, and the General Product Safety Directive (2001/95/EC) for overall consumer safety. These together form the basis for CE marking.
  
 Engineers and manufacturers must share responsibility for product safety and performance. Engineers and manufacturers must share responsibility for product safety and performance.
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 I_m = P_m / U ⇒ I_m = 42.16 W / 24 V = 1.75 A I_m = P_m / U ⇒ I_m = 42.16 W / 24 V = 1.75 A
  
 +\end{equation}
 +
 +**Energy saving by reutilizing water (Calculated with a water cleaning power usage of 2 kWh/m^3 and a water waste of five liters per shower) = (0,002 kWh/L)**
 +
 +
 +\begin{equation}
 +P_c = 0,002 kWh/L * 5 L = 0,01 kWh 
 \end{equation} \end{equation}
  
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 === - Hardware === === - Hardware ===
  
-Some modifications were made to the prototype compared to the original design. The most significant change is that the valves placed after the water tank were not included in the prototype which will be part of the final product.+Some modifications were made to the prototype compared to the original design. The most significant change is that the valves placed after the water tank were not included in the prototype which will be part of the final product (See figure {{ref>PrototypeLabelled}}). 
 +<WRAP> 
 +<figure PrototypeLabelled> 
 +{{:prototypelabeled.jpg?400|}} 
 +<caption>Labelled prototype</caption> 
 +</figure> 
 +</WRAP>
  
-The prototype still demonstrates the core functionality of the system. It clearly shows how cold water is first directed into the water tank, and once the water warms up, it flows to the shower. In the final version, the cold water stored in the tank would later be used for toilet flushing.+The prototype still demonstrates the core functionality of the system. It clearly shows how cold water is first directed into the water tank, and once the water warms up, it flows to the shower. In the final version (See figure {{ref>PrototypeStructure}}) , the cold water stored in the tank would later be used for toilet flushing.
  
-Eventhough some components are missing from the final product, the prototype successfully shows how the temperature difference of the water controls its direction with the valves, and how the system saves water.+<WRAP> 
 +<figure PrototypeStructure> 
 +{{:prototypestructure.png?400|}} 
 +<caption>Final prototype on structure</caption> 
 +</figure> 
 +</WRAP>
  
 +Even though some components are missing from the final product, the prototype successfully shows how the temperature difference of the water controls its direction with the valves, and how the system saves water (see figure {{ref>PrototypeSchematic}}).
 +
 +<WRAP>
 +<figure PrototypeSchematic>
 {{:prototype_azuloop_schematic.jpg?400|}} {{:prototype_azuloop_schematic.jpg?400|}}
 +<caption>Schematic of the Azuloop prototype </caption>
 +</figure>
 +</WRAP>
  
 === - Software === === - Software ===
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 === - Tests & Results === === - Tests & Results ===
  
-After completion of the prototype assembly, the testing phase began with pressurization and electrical tests to verify that the assembly could withstand the expected water pressure. During the initial test, several water leakage points were identified around the pipes and fittings. As a corrective measure, the pipe fittings were sealed using a sealing compound. The electrical test was completed successfully and did not require further modifications.+After completion of the prototype assembly, the testing phase began with pressurization and electrical tests to verify that the assembly could withstand the expected water pressure. During the initial test, several water leakage points were identified around the pipes and fittings. As a corrective measure, the pipe fittings were sealed using a sealing compound. The electrical test was completed successfully and did not require further modifications.  
 + 
 + 
 +Following the sealing of the weak points, a second pressurization test was conducted and successfully completed. During the first two testing phases, issues were encountered with the ESP32 microcontroller. As a workaround, the microcontroller was bypassed during the electrical test by manually applying voltage to the relay coils using jumper cables. A 12V supply was connected to the relay switch, which also enabled testing of the solenoid valves. A power supply unit was used to provide both 5V and 12V outputs as required (See figure {{ref>PrototypeTest}}). 
 + 
 +<WRAP> 
 +<figure PrototypeTest> 
 +{{::prototypetest.png?400|}} 
 +<caption>Prototype got manually handled. Water came into the shower tank part.</caption> 
 +</figure> 
 +</WRAP>
  
-Following the sealing of the weak points, a second pressurization test was conducted and successfully completed. During the first two testing phases, issues were encountered with the ESP32 microcontroller. As a workaround, the microcontroller was bypassed during the electrical test by manually applying voltage to the relay coils using jumper cables. A 12V supply was connected to the relay switch, which also enabled testing of the solenoid valves. A power supply unit was used to provide both 5V and 12V outputs as required. 
  
 The third test included a functionality check of the microcontroller, with a focus on sensor readings, temperature setpoint control, and automated valve switching sequences, in order to validate the full software control loop. The third test included a functionality check of the microcontroller, with a focus on sensor readings, temperature setpoint control, and automated valve switching sequences, in order to validate the full software control loop.
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 Perform the hardware tests specified in [[report|1.6 Tests]]. These results are usually presented in the form of tables with two columns: Functionality and Test Result (Pass/Fail). Perform the hardware tests specified in [[report|1.6 Tests]]. These results are usually presented in the form of tables with two columns: Functionality and Test Result (Pass/Fail).
 +
  
 == Software tests == == Software tests ==
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 **Performance Tests **Performance Tests
 ** **
-Performance validation focuses on system responsiveness and timing characteristics.+The table below demonstrates that our product accurately measures water temperature, enabling responsive actions based on user preferences. Here, Tw represents the actual temperature of the incoming water, while Twp indicates the temperature detected by the prototype sensor. As the water temperature changes, the sensor readings closely match the actual water temperature in real time. S1 refers to the first scenario, where the water is colder, and the second scenario shows the water after it has been heated. The sensor’s accuracy is within 1°C of the actual temperature.
  
 <WRAP round box 400px> <WRAP round box 400px>
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 </table> </table>
 </WRAP> </WRAP>
 +
  
 **Usability Tests **Usability Tests
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 The tank will be subjected to 30L water capacity (equivalent to 1,720 Pa maximum pressure at the bottom) through nonuniform pressure distribution simulation. The analysis will evaluate von Mises stress concentrations, particularly at critical locations such as base-wall junctions and corner regions where maximum stresses occur. Material yield strength will be compared against calculated maximum stresses to ensure a minimum safety factor of 2.0. Displacement analysis will verify that wall deformations remain within acceptable limits. The structural test passes if maximum stress values stay below material yield strength with adequate safety margins, and if no excessive deformation or structural failure occurs under the specified hydrostatic load conditions. The tank will be subjected to 30L water capacity (equivalent to 1,720 Pa maximum pressure at the bottom) through nonuniform pressure distribution simulation. The analysis will evaluate von Mises stress concentrations, particularly at critical locations such as base-wall junctions and corner regions where maximum stresses occur. Material yield strength will be compared against calculated maximum stresses to ensure a minimum safety factor of 2.0. Displacement analysis will verify that wall deformations remain within acceptable limits. The structural test passes if maximum stress values stay below material yield strength with adequate safety margins, and if no excessive deformation or structural failure occurs under the specified hydrostatic load conditions.
  
-Critical areas, such as the base-wall junctions and corners, were closely monitored for peak stress concentrations. The results indicated that the highest stresses are well below the material yield strength, confirming the structural adequacy of the tank design. The analysis also demonstrated that wall displacements remain minor, ensuring the tank’s integrity and functionality under operational conditions.+Critical areas, such as the base-wall junctions and corners, were closely monitored for peak stress concentrations. The results indicated that the highest stresses are well below the material yield strength, confirming the structural adequacy of the tank design. The analysis also demonstrated that wall displacements remain minor, ensuring the tank's integrity and functionality under operational conditions. 
 + 
 +Overall, the structural test validates the tank's ability to safely contain 30L of water without risk of failure, supporting the prototype's viability for further development and real-world use.
  
-Overall, the structural test validates the tank’s ability to safely contain 30L of water without risk of failure, supporting the prototype’s viability for further development and real-world use 
 == Hydrostatic Pressure == == Hydrostatic Pressure ==
  
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 Mesh and run static analysis. Mesh and run static analysis.
 +
 +== Analysis Results ==
 +
 +=== Factor of Safety Analysis ===
 <WRAP> <WRAP>
-<figure strain> 
-{{ :strain.png?400 |}} 
-<caption>Strain test</caption> 
-</figure> 
-</WRAP>  
  
 +<figure safety> {{ :safety.png?400 |}} <caption>Factor of safety distribution</caption> </figure> </WRAP>
 +The factor of safety analysis shows exceptionally high safety values throughout the tank structure. The minimum factor of safety is 13.51, which far exceeds the required minimum of 2.0. The maximum factor of safety reaches 4.646e+13, indicating areas of extremely low stress relative to material strength. This confirms that the tank design is highly conservative and provides substantial safety margins against structural failure under hydrostatic loading.
 +
 +=== Strain Distribution ===
 <WRAP> <WRAP>
-<figure displacement> 
-{{ :displacement.png?400 |}} 
-<caption>Discplacement test</caption> 
-</figure> 
-</WRAP>  
  
 +<figure strain> {{ :strain.png?400 |}} <caption>Strain distribution analysis</caption> </figure> </WRAP>
 +The strain analysis reveals maximum strain values of 4.895e-05 (approximately 0.00005), which are extremely small and well within elastic limits for typical structural materials. The strain distribution shows higher concentrations at the base-wall junctions and decreases toward the upper regions of the tank. The low strain values confirm that the tank operates well within the elastic range with no risk of permanent deformation.
 +
 +=== Von Mises Stress Analysis ===
 <WRAP> <WRAP>
-<figure stress> 
-{{ :stressvonmises.png?400 |}} 
-<caption>Stress test</caption> 
-</figure> 
-</WRAP>  
  
 +<figure stress> {{ :stressvonmises.png?400 |}} <caption>Von Mises stress distribution</caption> </figure> </WRAP>
 +The von Mises stress analysis shows a maximum stress of 7.042 MPa (7.042e+06 N/m²) located at the base-wall junction, as expected from the hydrostatic pressure distribution. The stress gradually decreases from the bottom to the top of the tank, following the pressure gradient. For typical structural steel with yield strength around 250 MPa, this maximum stress represents only 2.8% of the material's yield capacity, confirming excellent structural adequacy.
 +
 +=== Displacement Analysis ===
 <WRAP> <WRAP>
-<figure Safety> + 
-{{ :safety.png?400 |}} +<figure displacement> {{ :displacement.png?400 |}} <caption>Displacement distribution</caption> </figure> </WRAP> 
-<caption>Factor of safety test</caption> +The displacement analysis shows maximum deformation of 0.02066 mm (2.066e-02), which is negligible for practical applications. The displacement pattern shows outward bulging of the tank walls, with maximum displacement occurring at the mid-height of the walls where bending effects are most pronounced. These minimal displacements confirm that the tank maintains its structural integrity and dimensional stability under the applied hydrostatic load. 
-</figure> +
-</WRAP> +
 === Conclusion === === Conclusion ===
-The structural stress test confirms that the tank design safely withstands the hydrostatic pressure exerted by 30L of water. The simulation results show that the maximum von Mises stress occurs at the base-wall junctions and remains below the material’s yield strength, ensuring a minimum safety factor of 2.0 is maintained throughout the structure. Displacement analysis further verifies that wall deformations are within acceptable limits, indicating no risk of excessive deformation or structural failure under the specified load conditions+The comprehensive structural analysis confirms that the tank design safely withstands the hydrostatic pressure exerted by 30L of water. All analysis results demonstrate exceptional structural performance: 
 + 
 +Factor of Safety: Minimum 13.51 (>>2.0 required) 
 + 
 +Maximum Stress: 7.042 MPa (well below yield strength) 
 + 
 +Maximum Strain: 4.895e-05 (elastic range) 
 + 
 +Maximum Displacement: 0.02066 mm (negligible) 
 + 
 +The simulation results validate the tank's structural adequacy with substantial safety margins, supporting the prototype's viability for further development and real-world implementation.
 ==  Conclusion of the tests == ==  Conclusion of the tests ==
        
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