Course:VANT151/2022/Capstone/APSC/Team1

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Project: Energy Recovery Dryer

Welcome to Team 1. We are first-year students from UBC's Vantage Applied Sciences. Energy Recovery Dryer is our multidisciplinary engineering design project about the product of a cloth dryer with our innovation.

Project Overview

The project's goal is to create a scaled-down version of an Energy Recovery Clothes Dryer. The primary goal is to combine cross-functional teams and create interdisciplinary engineering ideas to develop a clothes dryer using the unique expertise. Some of the heat created was captured and cycled back into the system, eliminating waste. This conserves energy and adds to the long-term sustainability of the system. The five sub-teams are documentation, electrical, mechanical, structural, and user interface.

Problem Statement

Standard dryers on the market today consume and waste a lot of energy by constantly heating fresh air and expelling it after a single use. We need a new type of design that uses energy sustainably through efficient methods and design.

Team Requirements

Functions

• Can receive the user's instructions and react.
• There are two washing modes that users can choose (auto and custom).
• The user can control the time and temperature.
• Has a pause function in the drying process.
• The LED can display the options corresponding to each key step.
• Temperature, dryness, and remaining time can be displayed.

Objectives

General objectives to achieve as thoroughly as possible:

• Safe and easy-to-use user interface

• Effective energy recovery

• High-speed to dry items

Constraints

• Size not exceeding 250 x 220 x 300 mm.
• At least 0.5 L capacity, able to dry a cotton handkerchief, size 15 x 15 cm (‡ 3 cm)
• Drying within 1 hour.
• Maximum allowable electrical power consumption: 24 V AC, 40 VA.
• Alphanumeric LCD display and navigation buttons for the user interface.
• Automatic operating mode
• Manual operating mode: able to set desired
• Drying time
• Temperature
• Dryness

Gantt Chart

Ganttchart Figure 1.1

Ganttchart Figure 1.2

Mechanical Design

Requirements

Functions

• A drum as a container to hold the clothes
• A function to rotate the drum
• An air chamber tube to lead air that is blown by the fan to reach the drum
• A motor support to make the gears well connected
• A cold system that can cool down the hot air
• A function to utilize some of the heat
• A sensor mount to hold the sensors inside the drum
• The drum needs to be rotated by the gears and the motor
• The air blown by the fan needs to achieve the heater and the drum
• The sensor must be held to monitor the temperature and the humidity
• The drum must not damage the clothes

Objectives

• The drum rotation speed should be kept properly to achieve the highest efficiency'
• The air blown by the fan should be recycled
• The material should be used properly to reduce the waste
• The sensors and the motor should not be damaged
• The capacity should be as large as it can be
• The dryer should have a long working life

Constraints

• The size of the drum should be no more than 250 * 220 * 300 mm
• The capacity of the drum should be at least 0.5 L to contain a cotton handkerchief, which is 15 * 15 cm (3 cm) within 1 hour

The Design

The mechanical sub-team is responsible for the design of the drum drive, motor and sensor mount, heat exchanger, fan, and 3D print. For every part, we designed at least one alternative design and chose the best one to print after we compared all the designs except for the sensor mount.

Name	Image	Description
Drum Drive	Figure 2	For drum drive, we designed three different kinds of driving models, which are shown in Figure 2, one of them is designed to rotate the drum by using two helical gears, another one is designed to rotate the drum by using two spur gears, and the last one is designed to rotate the drum by using a belt. At last, we decided to use the first design, which is the two helical gears. During the design, we used SOLIDWORKS to draw the model of the two helical gears by determining their modules, teeth numbers, inner and outer diameters, and the distance between the centers of these two circles while considering the rotation speed and the efficiency.
Gear Position	Figure 3	For the position of the gears, we created two designs, which are shown in Figure 3. The first design (final design) is aimed to fix the drum between the air ducts and the front wall by nailing three rollers to the front wall to hold the drum. The second design is aimed to hold the drum by adding a support ring to the air ducts.
Motor and Sensor Mount	Figure 4	The designs of motor and sensor support are shown in Figure 4. The first design of the motor is designed for a lower position, which would need a huge space to support the motor firmly. The other design of the motor (final design) is designed for a higher position, which would fit the drum gear better. The sensor mount is placed on the air ducts. The position of the sensor mount is designed by considering its size and the accuracy of the measurements of the temperature and the humidity.
Heat Exchange System	Figure 5	The design of the heat exchange system is shown in Figure 5. The heat exchange system is a combination of air ducts, a clear pipe, copper tubes, and a sleeve. The hot and cold air would exchange through the air ducts, and the copper tubes would transfer the hot air to the tray.
Air Ducts	Figure 6	The SOLIDWORKS design of the air ducts is shown in Figure 6. The conical object is designed to hold the heater, and the hollowed-out parts are designed to let the air in and out.
Fan	Figure 7	The SOLIDWORKS model of the fan is shown in Figure 7. We use our fan instead of the one that gave by the professor. Our fan has a faster speed that could blow more air to the air ducts, which would increase the efficiency. In order to fit our fan into the frame, we decided to put it on the top corner of the right-side wall.
Air Tube	Figure 8	The SOLIDWORKS designs of the air tube are shown in Figure 8. The first design of the air tube is aimed to gather the air blown by the fan to the air ducts to increase efficiency. However, the size and the shape of the air tube could not fit the fan. The second design of the air tube is also aimed to gather the air blown by the fan to the air ducts to increase efficiency as while as it could fit the fan and connect the fan to the air ducts.
Baffle (Extra feature*)	Figure 9	The SOLIDWORKS design of the extra feature (baffle) is shown in Figure 9. This extra feature is designed to speed up the drying of the handkerchief, which include an inner drum layer and six baffles.

Drum Size

The diameter of the drum is approximately 10.48cm, and the capacity is about 0.5L.

Drive System and Motor Support

The drum drive is an assembly of a motor and two helical gears. The motor would lead the small gear to rotate, and the small gear would rotate the drum gear, then the drum rotate with the drum gear.

The motor support is aimed to hold the motor firmly and increase the height of the motor to let the small gear that is placed on the motor match the drum gear.

Heat Exchanger Top

The heat exchange cover is designed to hold the copper tube and the tray. The heat exchange cover would be nailed to the back panel to fit its position with the copper tube.

Temperature and Humidity Sensor

The temperature and humidity sensor is placed inside the drum and is close to the air outlet. The design of the placement of the temperature and humidity sensor is aimed to increase the measurement accuracy.

Electrical/Electronic Design

Overview of the electrical and electronic sub-system

Requirements

Functions

1. Dry the clothing by controlling the heater, motor, and fan.

2. Monitor the temperature of the drum and humidity of airflow.

3. When the clothing is dried, the dryer should be turned off automatically.

4. Control the temperature in the drum.

5. When the drying is finished, the buzzer makes a sound to remind the user.

6. The drum can rotate in two different directions (clockwise and counterclockwise).

7. Clothes are not stained or damaged.

8. Dry the clothing completely.

9. Not damage to the motor.

Objectives

1. Energy saving

2. Short drying time

3. High code efficiency

Constraints

1. The temperature in the drum is lower than 75.

2. The maximum allowable electrical power consumption is 24 V AC, 40 VA.

3. When the heater runs, the fun must be turned on.

4. The breadboard should be put inside the frame.

The Design

Auto pattern

If the user chooses the auto pattern in the user interface, codes made by the electrical sub-team will be executed automatically. For the Auto pattern, the fan, and the motor will be started. The heater will be stated if and only if the temperature of the drum is lower than the secure temperature based on clothing type. When the predetermined humidity is reached, drying is finished (motor, fan, and heater are down).

Custom pattern

If the user chooses the custom pattern in the user interface, the fan, and the motor will be started. The heater will be stated if and only if the temperature of the drum is lower than the custom temperature. The drying is finished after the custom time (motor, fan, and heater are down).

Temperature and Humidity Sensor

Sensor position

Figure 10.

Fogure12.

There are three designs for the sensor position.

The first is to put the sensor in the air intake ducts (inside the drum), the second is to put it in the air outlet ducts (inside the drum), and the third is to put it on the outside of the drum. Finally, the sensor mount is placed on the air outlet ducts (inside the drum), where can get more accurate humidity and temperature. If the sensor is placed in the air intake, the humidity is not inaccurate.

Figure11.

Standard Humidity

In the Auto pattern, the drying is finished when the clothing inside is dry. In order to check whether the clothing is dry or not, standard humidity is required. The experiments were made on different days to determine the standard humidity.

The average of all experimental data was chosen as standard humidity.  

Control Programs

Figure 13.

Check humidity

In the Auto pattern, the drying is finished when the clothing is dry. In order to check whether the clothing is dry or not, I designed three algorithms. The first is to gain a standard humidity by experiments. If the humidity of the drum is equal to the standard humidity, the clothing is dry. The second is to check if the humidity of the drum keeps unchanged. If the humidity of the drum remains decreasing, the clothing is not dry. Finally, I chose the third, which is a combination of the first and the second. The reasons are as follows. The pre-determined humidity was decided by experiments. Considering that humidity varies from day to day, a double-check is necessary. When the humidity of the drum reaches the pre-determined humidity, the code will check if the humidity remains unchanged. If the humidity continues to decrease, the drying will continue until gaining the constant humidity.

Figure 13. The First Design

Figure 14. The Second Design

Debounce

In order to avoid false triggering, a debounce delay code was made. For events that are triggered consecutively within a short period of time, the previous time is cleared when triggered repeatedly within a certain period. Namely, only the last time is recorded.

Extra Features

Switch

Figure 15.

In order to ensure the safety of the user, the drying is supposed to stop when the door is open. A switch is secured on the door of the drum. If the door is not closed, the switch is not pressed. If the Arduino does not receive a low signal from the switch pin, which means the door is not closed, the motor, the heater, and the fan are forbidden to run.

Reset Button

Figure 16.

The user may want to open the door during drying safely to add or take clothing. Therefore, a reset button was designed. When the button is pressed, the reset pin will accept a low signal. After receiving the low signal, the Arduino will reset, which means the fan, the motor, and the heater stops running.

Buzzer

The buzzer was used to remind the user of the start and the end of drying. During drying, the users can do anything they want. When the drying is completed, the buzzer will remind the user of taking clothing.

Figure 17.

Rotation Direction

The purpose of this code is to control the motor to turn in clockwise and counterclockwise, enhancing the sustainability of the drum. the measure is to spaw the power pole between two wires of the DC motor, each is either clockwise or anti-clockwise. The circuit diagram is designed this way because it requires a relay to express two circuit signals (forward rotation and reverse rotation).

Figure 18.

User-Interface Design

User interface refers to helping users interact with EnerRec.Dryer. Users can give orders the to machine and it will receive instructions and respond accordingly. The EnerRec.Dryer is combined with four buttons and an LCD screen. Each button has a different function in each step.

Requirements

Functions

1. The EnerRec.Dryer can receive instructions from the user and respond accordingly.

2. User can select dying mode through buttons.

3. The EnerRec.Dryer has multiple washing modes which can be selected by the user. (Auto and Custom)

4. In custom mode, users can control time and temperature, if they want.

5. In auto mode, users can choose two modes (Normal and Delicate).

6. The EnerRec.Dryer has a pause function during drying.

7. LED can display the options corresponding to the buttons in each step.

8. Users can receive feedback from LCD.

Objectives

1. User can simply control the dryer.

2. LCD display information concisely and user can read it easily.

Constraints

1. The module of LCD is 20×4, which can display four rows and twenty characters in one row.

2. No more than 5 buttons.

3. User-selectable drying temperature.

4. User-selectable drying time.

The Design

Program Flowchart

Evaluation of Flowchart

Figure 19. Selection 1

Figure 20. Selection 2

We have two choices to decide the number of the buttons.

Figure 21. Final flowchart

We finally choose the right side one (Selection 2), in which we add two buttons to simplify the operations. Especially, the confirmation function is represented by the middle button rather than the two original buttons. Another added button is used to pause programming during processing. In auto mode, two modes(Normal and Delicates) replace the original three modes(High temperature, Medium temperature, and Low temperature). The benefit is that the user can clearly choose the mode according to the type of clothing, rather than the fuzzy high temperature, medium temperature, and low temperature.

Final program flowchart

The final program flowchart (Final flowchart) is according to the function of Selection 2 and our code.

Hardware Layout

The design has four buttons and one LCD at the top of the Dryer, three buttons are directly below the LCD and one is at top of the LCD. One is the reset button, one is the ok button and the other two are used to select mode.

Table 1.

	Accessibility	Extra buttons	Arduino limitation	Aesthetic (top acrylic board)	Total score
Two buttons		1	1	1	3
three buttons		1	1	1	3
Four buttons	1	1	1	1	4
Five buttons	1				1

We finally choose four buttons design in which each button has functions accordingly and clearly to understand the function for the user. In addition, Arduino has enough pins to connect and the buttons on the top acrylic board do not crow.

The circuit diagrams of four buttons are shown below.

Figure22.

Figure 23. button keycap

Feature

1. We add four buttons cover for the button design (button keycap). Make the user feel more comfortable when pressing the button. We chose a very cute shape, which is more attractive to the user.

2. In the custom mode, when the user wants to increase the temperature and time quickly, they can long-press the left or right button.

Operating Sequence

Long press the middle button for 3 seconds, the screen will show "welcome, we are team 1", then the screen will show our home page. There are two modes to choose from, which shows in the third row. Press the left button, the LCD will go to Auto mode. Press the right button, the LCD will go to the Custom mode. In Auto mode, there are also two selections on the third row. One is Normal, in which the temperature is 75℃ and the other is Delicate, in which the temperature is 45℃. Then, it will start automatically by using a temperature and humidity sensor to determine whether the clothes are dried. In Custom mode, the screen will print "the highest temperature is 75℃. Then, the user can choose the temperature and the user cannot change it higher than 75℃. If the user presses the left button, the temperature will increase by 5℃ and if the user presses the right button, the temperature will decrease by 5℃. Long press the right button or left button, and the temperature will continuously increase or decrease. If the middle button is pressed, the screen will change to "Choose your time" and the user cannot change time lesser than 0 min. If the user presses the left button, the temperature will increase by 5 min and if the user presses the right button, the temperature will decrease by 5 min. Long press the right button or left button, and the time will continuously increase or decrease. When the user has already chosen the mode, the screen will change to "Drying begin", and " processing".

LCD display picture

When the Arduino is connected to the computer, the LCD will light up, but does not print anything.

Figure 24.

Press the middle button for 3 seconds, the LCD starts to print.

Figure 25.

Figure 26.

Press the left button for Auto and the LCD will show two selections.

Figure 27.

Press the left button for Normal mode.

Figure 28.

Press the right button for Delicates mode.

Figure 29.

After the Home page, if the user chooses the Custom pattern, the LCD will ask the user to choose the temperature.

Figure 30.

Figure 31.

Pressing the left button can decrease 5℃ every time, and pressing the right button can increase 5℃ every time. If the user presses the left button or right button for a long time, the time will continue to increase until the user stops pressing the button. Press the middle button will confirm the final temperature.

Figure 32.

Figure 33.

Pressing the left button can decrease 5 min every time and pressing the right button can increase 5 min every time. If the user presses the left button or right button for seconds the time will continue to increase until the user stops pressing the button. Press the middle button will confirm the final time.

Figure 34.

Before the dryer run, the LCD will print "drying begin" and "processing".

Figure 35.

Figure 36.

When the dryer finish running, the LCD will print "Caution, may hot inside".

Figure 37.

Recommendation

Firstly, in order to make the user have a better experience, we can add a return function, meaning the user can go back to the last page if they select the wrong button. For example, the auto page can return to the home page as well as if they choose the wrong temperature, but it has already gone into selecting time page, they can back to choose temperature again. Secondly, we choose three buttons for our dryer at first, but later we want to add a reset function and a better way is to add a button. We asked the structure sub-team to re-cut the acrylic board. This caused them problems and we should have designed it at the beginning of the project.

E and U sub-teams' video demo

Video1 from (YouTube)

Structural Design

Overview of the mechanical sub-system

Requirements

Functions

Structural Design designs the whole frame of the dryer including:

1. A metal frame which holds the entire external structure of the dryer.
2. Metal sheets for tray and backside which hold in place the internal parts by screws.
3. An acrylic sheet for the top side to determine the position of buttons and LCD
4. The position of door opening in order to make the user open the door easily and enables the dryer to form an enclosed space.

Objectives

1. The dryer has lightweight and easy to bring.
2. The dryer has a large capacity.
3. The dryer has a strong structure.
4. The position of the LCD and buttons are clear and is easy to use.
5. The storage of the dryer should contain all the working parts.
6. The door should be firmly attached to the base frame when closed.

Constraints

1. The size limitation of the dryer should be 18cm * 26cm * 18cm.
2. The size limitation of the front wall must be 19cm*19cm.
3. The size limitation of the side wall must be 26cm*18cm.

The Design

Enclosure

Figure 38 This picture shows 3 views of the frame.

In addition to using screws to fix each metal frame, we also use corner brackets to strengthen the connection of the two metal frames. Thus forming a very strong framework.

Door

This picture shows two designs of the door. We chose the second design of the door because we thought that the shape of the second design has a more complete circle, which is easy to cut and has relatively good integrity. The lack of the extra part highlighted by the first design also enhances the strength of the entire door. The more regular shape also allows us to have more flexible angles to place the door during the installation process.

Here are the drafts of two-door designs and one three-views of the final design.

Figure 39

This picture shows 3 views of the door.

Figure 40

Top side

We designed the two drafts of the position of the LCD and buttons and finally chose the first one where the buttons are below the LCD. It is because the choice one that buttons near the LCD is not more aesthetic than the choice two. In addition, using the choice two, users can use the buttons corresponding to the functions on the LCD. If the chosen one is used, the absence of the corresponding function names will confuse the users for pressing the buttons. Here are the drafts of two designs and one three-views of the final design. The three-view of the top panel design draft design of LCD & buttons 1 draft design of LCD & buttons 2

Figure 41

Figure 42

Figure 43

Water Collection Tray

Figure 44

The edge of the tray is designed to protrude so that it is easy to hang the tray directly under the pipe like a drawer. Similarly, the shape of the tray is designed for fitting directly into the pipe, so that water does not leak out. We chose to move the water collection tray down to the position close to the bottom plate, so we also removed the three support feet at the bottom of the sink bracket to simplify the shape of the parts. Here is the three-view of the tray.

Conclusion- End Product

The result is a durable dryer that uses less energy than conventional dryers and works by recycling heat. As described above, it has four buttons to operate the system. Two of them are mainly used and can be chosen by the user to dry the items, whether auto or custom. The bottoms and the dryer can determine the temperature, time, and humidity to satisfy their needs. It has a special fan, creating a better energy recovery efficiency. The dryer is a better choice for people who want to contribute to a sustainable planet now that they know its qualities. In addition to using less energy, this dryer's design takes up less time, which precisely accommodates the needs of time-constrained users and professionals such as students and office workers who need a fast-drying speed.

Appendices

Assembly Drawing

Renderings and photo view 360

References

Download the 3D print files tagged with keyword Keycap. Cults. (n.d.). https://cults3d.com/en/tags/keycap?only_free=true&page=1

Riyanto, W. (2022). Free CAD designs, Files & 3D models: The grabcad community library. Free CAD Designs, Files & 3D Models | The GrabCAD Community Library. https://grabcad.com/library/lcd-16x2-arduino-1

Shaulsk, M. (2022). Free CAD designs, Files & 3D models: The grabcad community library. Free CAD Designs, Files & 3D Models | The GrabCAD Community Library. https://grabcad.com/library/tactile-push-button-b3f-405-12x12x7-3mm-with-cap-1/details?folder_id=12347381

Smite, H. (2015). Free CAD designs, Files & 3D models: The grabcad community library. Free CAD Designs, Files & 3D Models | The GrabCAD Community Library. https://grabcad.com/library/minibreadboard-1

About Us

All Sub-Teams members

Documentation
First name: Emily Family name: Chen I have contributed to this project by organizing other sub-team works, slides of the presentation, as well as creating the wiki website. I learned some critical skills in the course, including how to communicate with team members and work in a group sufficiently.	First name: Yifan Family name: Zhao I am responsible for collecting information about team members and uploading graphics to Wikipedia. I learned the importance of cooperation in group activities.
Electrical/Electronic
First name: Jiajie Family name: Sheng My contribution to this project is mainly in designing the program and solving the multi-signal output of the motor to control the bidirectional rotation. In the process, my knowledge and understanding of circuits and signals has improved significantly.	First name: Jiayue Family name: Yang I am team leader and Electrical sub-team member of this team. As a team leader, I am responsible for organizing meetings to ensure the smooth running of all activities. As Electrical team member, I am responsible for designing circuit and algorithm of controlling system software based on the Arduino platform. From this project, I learned how to organize team activities and talk with team members. As electrical team member, I learned how to design a logical algorithm to meet demands of the user.
Mechanical
First name: Yingqi Family name: Qiao My name is Yingqi Qiao, also named as Glen. I am in the mechanical sub-team in team 1. I am responsible for the motor stand and helical gear design. In this project, I learned how to use various software to make the work easier and increase the efficiency, then teamwork is the most important for the group projects.	First name: Wenyi Family name: Cai I am Wenyi Cai (Sophie), responsible for part of the mechanical designs. I have learned many skills by studying this course, for instance, SolidWorks functions, 3D prints, different gear types, and the importance of teamwork.
Structural
First name: Perry (Peihong) Family name: Chen My name is Perry Chen, and it's my first-year study at UBC. I worked in the structure sub-team in this project. I was involved in assembling the frame, designing and modeling the door assembly, and punching holes for the components. Through this project, I learned a lot of knowledge, such as modeling skills and 3D printing technology, and also experienced the joy of handcrafting.	First name : Qingyi Family name: Liu My name is Qingyi Liu, and I am a first-year student at UBC. In this project, I worked in the structure sub-team and my main job is to assemble the whole frame of the dryer. From this project, I learned a lot of skills for the structure such as solid work, laser cutting, and so on.
User-Interface
First name: Gaosheng Family name: Chen Aaron Chen is one of two members of user-interface, who involved in designing switches, keycaps and programing. While this activity, my communication skill and cooperation skill were practiced.	First name: Jingrong Family name: Tian My name is Jingrong Tian, and this is my first year at UBC. In this project, I am a member of the user-interface sub-team, who contribute to buttons and LCD on the top of our EneRec Dryer. After this project, I learned the connection between Arduino and LCD, and the new code to control the LCD.