A Lesson in What Not To Do

Being in Engineering definitely makes you view the world around you differently.

I have spent my last two work term designing the mechanical systems used in buildings (such as the heating and air conditioning systems). If I do my job right, you'll never notice all of the work that I've done (because you will always be a comfortable temperature and all of the ugly and noisy mechanical equipment will be hidden away).


On my bus ride home from work, I pass by this apartment building which is always a reminder to me of what not to do! Overall, this apartment building looks very well kept, out front there is lots of nice landscaping. However, when I look at this apartment building, all I can see is the TERRIBLE location of the mechanical roof top unit!

In the picture below, I've zoomed in on the penthouse patios which are supposed to open to a beautiful view of the sky. Unfortunately, some mechanical engineer located a roof top unit right behind the opening. Now all you can see when you look up is the mechanical equipment which completely destroys the view that the architect was aiming for!


This is a perfect example of why it is so important to see the bigger picture and to think a problem through from all angles. I'm sure this piece of equipment keeps the apartments the right temperature but because the engineer forgot to think about other implications of her/his mechanical system, the view has been destroyed.

Wouldn't it be cool if you had a gigantic multi-touch computer screen (like the iPhone)? Well, we made one for our 4th year design project. The screen measures 48" diagonally, a nice size for a workspace or for multi-player games. Here's a video of our table in action, running on Windows 7.



How does it work? We used a physics phenomenon called frustrated total internal reflection. If you shine light into the side of a sheet of acrylic (Plexiglas), the light will be trapped inside due to total internal reflection (gr 12 physics). Now when you touch the surface, it "frustrates" the light at that spot and so light escapes. You use a camera to capture this image and figure out where the finger was pressed. You can see a picture of what our camera captures when a hand touches the table:



Clarification: The team consists of myself and 3 male classmates. Nonetheless, 25% is still several times higher than the percentage of female students in my class.

What I do at work:

Whenever people ask me exactly what I do at work, I find it very hard to describe. I usually give them a vague reply like “I design the mechanical systems in buildings”. Although, I know that this doesn’t really mean much to most people. So I thought I’d write a blog post where I try to actually explain what I do at work.

The mechanical systems that I design are the heating, ventilation, air conditioning and plumbing systems within buildings. This might sound straightforward but there are a lot of different variables involved.

The first thing that needs to be determined is which type of systems will be used and how heating and cooling will be provided. Most commonly, an air handling unit is used to heat and cool air which is then blown into the space that you are trying to heat or cool.

There are a few different options for how heating and cooling will be provided. Here are some examples of how the air can be heated within the air handler:

-Hot Water Coils: Hot water runs through metal coils and a fan blows the air over the coils so that the heat will transfer from the hot water to the air.
-Electric heat: Air is heated by being blown over electric heating coils.
-Gas heat: Gas is burned within the units to heat the air.

Every system has pros and cons. For example, hot water coils are very efficient but require a lot of space because a boiler is required to heat the hot water (and pumps to circulate the hot water).

Once you’ve figured out how you are going to provide heating and cooling, you need to figure out how you are going to keep all of the spaces that the air handler services comfortable at the same time. The air handler will service many different spaces and they won’t always need the same amount of heating and cooling. Here are a couple different options for that:

-Control Air Volume (CAV) Systems with terminal re-heat: Use your air handler to heat the air to the lowest temperature required by any of the spaces you are controlling. Then use a small re-heat unit in each space to increase the temperature for just that space to whatever it requires. (Now you have to go back and determine how you will provide this heat - hot water or electric?).
-Variable Air Volume (VAV) Systems: Use your air handler to heat the air to be really hot (or really cold) but control the amount of air which flows into each room. If a room is already a good temperature, don’t supply it with air. If a room is really cold, provide it will lots of air. Etc...

Each of these systems has their own pros and cons. A CAV system is great if your rooms will usually all need the same amount of heating and cooling but a VAV system is better if there is lots of variation between the rooms.

Next, you need to determine how much heating and cooling each space will likely require. This is done by determining where you will loose heat and where you will gain heat. For example, windows will make the space loose heat and people will make the space gain heat. This is important so that you can determine how much airflow each room will need and how large your air handling unit must be.

Once you’ve decided all of that, you need to determine how you will get the air to the space (i.e. with ductwork). This requires lots of coordination with the architect and structural engineer to make sure that ducts will fit within the ceiling space.

Once you’ve brought the air into each room, you need to select diffusers appropriate for the space. When selecting diffusers, it is important to consider noise and speed. You don’t want your diffusers to be sending out so much air that they make a whistling noise or that people feel drafts of hot (or cold) air blowing on them.

Ultimately, what I love about my job is that every day is different because every building is different. This means that I am constantly learning and everyday provides a new challenge.

The classes that most strongly relate to what I do at work are heat transfer and fluid mechanics.

Engineering in Classical Rome

A couple terms ago, as an elective, I took a course on Roman Art & Archaeology. The course as a whole was very interesting but one small aspect of the course really caught my attention. One of the items that we discussed was Roman aqueducts.

Historically, cities always had to be located close to a body of water because all humans need water to survive. This really limited where cities could be located. Before the classical period, there was no way to transport water across long distances (think about how heavy water is!) but in ancient Rome they engineered a system for transporting water across great distances using aqueducts.

Aqueducts were large structures that spanned great distances at a very slight angle. These aqueducts connected large bodies of water to remote city locations and used gravity to maintain a continuous flow of water into the city. Some aqueducts even ran through mountains – the engineers would tunnel through the mountain from each side and meet in the middle. This required incredible precision and is an amazing engineering feat!

When the aqueducts reached the city, the water was then directed into the homes and fountains of the city and for the first time in history, people had the luxury of running water into their homes!

It is really interesting to reflect on how much engineering has impacted the world – imagine life without something as fundamental as running water.

Final thoughts – what is yet to be invented that 2000 years from now will be considered as fundamental as running water?

Co-op Term on Campus

I am currently on a co-op work term, working on campus with a professor in the Department of Civil and Environmental Engineering. Working on campus is great. I did not have to suffer the trauma of traveling somewhere unheard of and I already know the bus route.

My boss has a contract with the Ministry of Transportation of Ontario (MTO) that involves predicting rainfall patterns throughout the province. The MTO is concerned with rainfall information because it would help them to design highways to handle the rainfall at a given location. Highways span the entire province, not just in cities areas where weather stations provide local data. Finding a suitable method of predicting rainfall patterns between stations is the objective of the contract. The challenge is that weather stations are so inconsistantly distributed. The stations are almost exclusively located in southern Ontario. This makes it difficult to predict rainfall in the northern parts of the province. The project involved an interim report, which will be my work report after a few tune-ups. It has also encouraged me to develop my computer skills emmensly. I did not know there was so much that I did not know.

Working in the faculty is a great experience. I have hands on experience with cutting edge research! Seeing the faculty from the inside changed my entire preception of universities. There is so much more that goes on than I knew about. Class is clearly not the highest priority, but it is all that a first year student sees. There is so much more after an undergraduate degree, so much fullfillment and so many applications. There is so much passion in the faculty. Everyone loves what they do, they would not have a PhD in it if they didn't. It is inspiring; it makes me want to learn!

My boss was teaching a graduate class this past term. It was very interesting to see such advanced applications of Civil Engineering, but also to see classes from the instructors perspective. He also manages all of the work reports for the faculty, actually his co-op (me) does this. It was nice to get so many tips on report writing from the guy who controls them.

Design Symposium

Well, I was intending on finding some pictures and getting permissions to post them from the people in them and the people who took them. However, as this draught has just turned one week old, I'll post it now, and come back and edit with pictures later.

One of the things that everyone in engineering at Waterloo has to do is a fourth year project. This varies from department to department, but what MME (Mechanical and Mechatronics Engineering) students do is to tackle a design project. There's two courses to this - ME 481 in the 4A term, where we have to design something, and then come up with enough detailed drawings, component lists, etc that we could give our final report to someone who knew nothing else about the project, and get it made exactly right. The second course is ME 482, in 4B. For Mechanical students this is optional, but for those of us in Mechatronics it's mandatory. This is where you build the project, and discover all the places where you left out information in the design phase.

On Monday, all the Mechatronics students had the penultimate part of our course. We took our finished projects and went to the great hall in the student life centre to set up our symposium. For four hours, we took questions from visitors to campus - lots of parents came, younger engineering students- especially the third year mechatronics students who have to do this next year, and other students who to figure out why the chairs that normally sit in the great hall had been moved.

My project was an automated window. Basically the relevant parts are that it will open and close itself, based on how warm it feels inside and outside. There's a couple of manual overrides, and a few other constraints on how it works, but those weren't why we made it. Basically we wanted to make something that would encourage green technology, things like opening the windows instead of turning on the A/C.

My partner and I were kept talking all afternoon, explaining to people what the project was. There were a surprisingly large number of people.

Mechatronics - Nut Sorter Project

One of the exciting things that I have done in Mechatronics so far is this Nut Sorter Project.

The idea is to design a Mechatronics system that can sort nut of different sizes and types. It should also be able to detect coins in the process and reject them. There were size constrains as to how big the sorter can be and we also had a budget that we had to work within.

At the start of the term we were given a kit that contained some sensors, stepper and DC motors and some basic electronics components. At the end of the term a competition was held to evaluate the sorter based on speed, accuracy and design.

Here is the picture of the nut sorter that our group had designed. This sorter works based on the shadow a nut casts. Depending on the size of the shadow, the nut is dispensed into the respective bin.

Attached are two of the videos that shows how the sorter works





Enjoy the videos. You can look at other nut sorter projects on Youtube.

Design of a Culvert Crossing

I am a current first year environmental engineering student. The final project for our 'Introduction to Civil & Environmental Engineering' course involved the predesign of a culvert crossing on campus. A culvert is a tunnel that allows water to pass through. They are often used to allow water to pass under roadways.

Currently there is a by-pass channel (flowing body of water) on campus. There is a crossing with two steel culverts that allows water to flow under the crossing. The project was to develop a more advanced culvert system that would be able to handle a greater amount and speed of water. The replacement culvert was to be designed to stand up to a hundred year storm. A hundred year storm is the largest storm that would be expected to occur in the area within a hundred year period.

We spent hours outside surveying the site. We recorded the elevations of the land around the channel and even put on waders and surveyed through the channel. We recorded the distance between all points so that they could accurately be plotted on an AutoCAD map.

Once the data were collected we created a map of the area, and developed a design for a replacement culvert. We had to consider the quantity and speed of water from a hundred year storm.

The project was very open ended. It was up to us to specify the finer details of the proposed crossing. We had the option of designing a sidewalk and guardrail if we thought it was necessary and we had to determine a suitable road width based on how much traffic the site sees. We had to compare the efficiency of 5 different culvert diameters and the number of culverts was completely up to us.

Ultimately, the design that I proposed included 6 culverts, each having a 1.2 meter diameter.

Through the experience, we all developed our surveying and autocad skills, and learned about report writing.