ONG KAI YANG

Background Information

The organisation we were attached to was SIT. The Singapore Institute of Technology (SIT) is a university created to achieve the objectives of being a leader in innovative learning by integrating learning, industry and community. Its mission is to nurture and develop individuals who build on their interests and talents to impact society in meaningful ways.

The aim of the project is to improve the ventilation system of hawker centers. In Singapore, Hawker Centers are a constant staple for anyone looking for cheap and good food. However, there are some Hawker centers which has a poor ventilation system which results in customers experiencing thermal discomfort. Through our project, we aim to improve the ventilation system of hawker centers which will thus improve the overall experience of the customer.

Elaboration of the Task

As our project is mainly focus driven on finding a way to improve the ventilation system of Hawker centers, we had to do our own research on basic physics concepts relating to airflow and how the different fan blade designs affect volume of airflow produced. Elias and I read through multiple articles and research papers to expand our knowledge on the topic then started our own draft for our literary research report. Once we had enough information on the topic, we began proposing our own solution.

The benefits of us doing our own research first is that we can better expand our knowledge on the topic first before going into the project blindly.

However, some challenges we faced was that since our knowledge on the physics topic of airflow is limited, we had some difficulty comprehending some of the information displayed online as it had multiple complex terms and concepts. We overcame this difficulty by seeking help from our teacher and SIT mentor in explaining some concepts and terms to us. Most notably was being taught to understand CFD simulation diagrams by our SIT mentor.

Record of results

Through this 1-month Internship, we wrote a report detailing information on our project and finally proposing a solution to solve the problem. We came up with multiple solutions and suggestions on how current fan designs in hawker centers can be improved too. Some improvements that could be implemented to current fan designs includes the Material of the fan and removing of winglets from HVLS fans.

1. Material

Some fans in hawker centers are made from metal and can rust in wet conditions. Especially in hawker centers where the air is humid, metal can rust easily in these conditions. When the fan rusts, it has the potential to interfere or come into contact with the internal fan components and reduce the efficiency of the fan. A more suitable material could be a strong plastic which will not decolourise and is lightweight and will not rust in such conditions.

2. Removal of Winglets from HVLS fans

Although Winglets help to better direct and increase airflow, a stronger motor is required to spin the heavier fan blades as winglets acts as additional weights on the blades and the increase in airflow is nearly negligible.

Finally, we proposed a situation to improve the ventilation system of hawker centers. Instead of just improving the designs of fan to improve volume airflow, we decided to look at our problem from a different POV. We found out that the main reason why customers experience thermal discomfort is because there is a build up of hot and humid air in the hawker centers. By just improving the designs of fans, it only aids in the continuous circulation of hot air and does not efficiently removes it within the hawker center. Thus, our proposed solution aims to quickly and efficiently remove the warm air in the haw We aim to direct the air towards many centralized points in the ceiling of the hawker centers called exhaust points.

We decided to mount axial fans blowing horizontally 2.3-2.4 meters above the ground at the sides of the hawker center. Average seating height has been taken to be 1.3m, with average standing height being 1.7m. These will be attached to an acrylic shield. Additional fans can be mounted on the sides of pillars along the way if necessary, to continue directing the airflow. The air is directed parallel to the ground to an exhaust point. which effectively removes the warmer air in the hawker center.

The acrylic shield helps to prevent vortices from occurring between the fans by limiting the space for vortices to form. The shield is made from acrylic to prevent discoloration as acrylic cannot degrade, thus maintaining a pleasing appearance.

Exhaust points are attached with an exhaust fan sucking up the warmer air to be removed in the hawker center.

This works mainly based on the fact that hot air rises. As the hot air produced from cooking exhausts or expiration from humans reaches the ceiling, it is being recirculated downwards again by the ceiling fan or the wall mounted fan as the opposite side of the fan blowing air sucks up air. The hot air being pushed downwards mixes with the cooler air and it increases the temperature of the cool air. After a while, it will be a constant temperature due to lack of removing this hot air efficiently before it’s recirculated in the hawker center again. This whole process circulates the air through the room, as air moves in to replace the air that has been pushed down from the ceiling.

An exhaust fan mounted on the ceiling forces this hot air away from the top of the hawker center to be efficiently and quickly removed. As the hot air is now removed from the hawker center, cooler air from outside of the hawker center takes up the space inside the hawker center and therefore cools the overall temperature in the hawker center, providing thermal comfort for customers Hawker centers.

Diagrams to show how airflow is channeled outwards with the use of fans

3 content knowledge/skills learnt

Firstly, I’ve expanded my knowledge on how fans work and basic airflow physics concepts. Such knowledge includes how characteristics of a fan, such as the number, size and material of the fan blade, will affect the volume of airflow produced. With a greater number of fan blades and larger size of fan blade will also increase volume airflow due to the greater surface area in contact with air to push the air particles. Material of the fan blade is an important factor in how much airflow it can produce, or the strength of motor required as a heavier material will add weight and will require a more powerful motor. A study conducted by Schmidt, K. and Patterson in 2001, compared the airflow generation and energy consumption of nine ceiling fans fitted with metal, wood, and plastic fan blades. They found out that fans fitted with wooden blades produced the least airflow due to the wooden fan blades being heavier and spinning at a slower speed. However, an advantage of it spinning at a slower speed allowed the fan to be quieter than the fans fitted with metal and plastic blades.

Secondly, I am now able to read and understand Computational Fluid Diagrams (CFDs). When I first saw a CFD, I was extremely confused and did not understand what the different colours and numbers means. Under the guidance of my SIT mentor, we found out that CFDs are actually quite easy to read. Just like a thermal camera, the red spots on the diagram shows areas of higher activity. On a CFD, the red spots indicate that fluids in that area are moving at a much greater speed or higher temperature compared to the lighter colour spots. Direction and movement of fluids can also be inferred from the diagram. The legends on the side of the diagrams indicates the value of what the programme is measuring.

Thirdly, I have learnt how to professionally write a scientific report. Initially, I have learnt how to write a scientific report through the normal school curriculum. However, there were some key components we were lacking in making our report look more professionally. Most notably is the adding of labels below our pictures and adding reference points to key concepts to diagrams for the user to easily refer to diagrams for easier understanding.

2 interesting aspects of your learning

Honestly, I was actually unsure what SIT really was as I was confused if it was a research company or a university. After asking the SIT mentors there, I found out that it was a mix of both. The people who are doing their research on the various projects issued to them by the various companies were professors who are also teaching in the university. That means they have to juggle teaching and doing their own research for their project. Undergraduates also helps in their project by forming a team and conducting research for the professor.

I found that the working environment in SIT is very conducive and the facilities there such as discussion rooms or project rooms are well furnished for users to use. Although I feel that working as a researcher may become quite stale and tiring at times, I believe that the reward of discovering something new or finding out a new solution to solve a problem can be very rewarding. Especially when I was working on our project with Elias and we had found a solution to solve the problem, we were both equally excited as the solution may very well help others live a better life.

1 takeaway for life

After this WOW! program, 1 takeaway for life is that I really appreciate the work that goes into researching. Although it may seem that everyone can do research and come up with solutions, a lot of effort is put in to make a report, carry out the experiment and more. Now, I am more aware of how difficult it is for people to come up with solutions to solve everyday problem. When we walk down the street, there are already multiple things that has been well thought by humans to solve everyday problems or simply make our lives easier.

Page updated

Google Sites

Report abuse