Week 9

After a few quiet weeks, we have lots to report! We’ve spent the last few weeks working on several small projects to incorporate into our new structure and as of today, most of them are complete! The main four components we’ve installed are a passive cooling “air conditioning” unit in the window, a two-tiered roof, a solar chimney, and a ventilated block near the bottom of the structure. Below are pictures and descriptions of each element.

In the bottom right corner, you can see our ventilated block. The team is still working on a few different molds to incorporate ventilation into the blocks, however this one did not require a new mold. We simply turned the block and added removable screen inserts to the holes. The benefits of this model are that it doesn’t require a new mold, the openings allow for cool air to enter the building, and the screens keep the bugs out and can be easily replaced if damaged. A practical issue with this method would be that turning the blocks might get in the way of reinforcing the structures with rebar which they often do in Senegal.

Above is the new two-tiered “cool roof” we’ve designed and installed. The design is pretty simple; there are two layers of corrugated steel with about 3 inches of open space between them. As the sun hits the top layer, the steel absorbs the heat, but instead of being absorbed into the house, it is then reflected by the inner steel layer and then the natural breeze flowing between the two layers pushes the hot air out before reaching the inside of the house. This seems like a viable option for the Senegalese people because it uses the same materials they typically use for roofs, so cost, aesthetics, and availability should not pose issues. Already we can see that it’s working as the top layer’s temperature is about 10-20 degrees hotter than the inner layer.

This is our passive cooling “air conditioner.” The idea behind this system is that there is a pot filled with cool water inside the window unit and the heat causes the water to evaporate which cools the air surrounding it. As a natural breeze comes through the unit, the cooled air will enter the home. While cost and availability of materials shouldn’t be an issue, one thing we might need to consider is the risks of having standing water in their homes as this provides the perfect breeding grounds for mosquitoes. To prevent this from happening, we could build a screen door of some kind on the interior to prevent bugs getting in from either side.

Our solar chimney builds off the simple principle that heat rises. By painting the chimney black, it will absorb more heat which causes the air inside to heat up and rise. As the hot air inside the chimney rises and exits, it continues to pull the hot air from the inside of the building up and out. This system works well with the ventilated blocks at the bottom because it creates a flow of cool air entering and hot air exiting.

Just after one day we are noticing huge changes inside the structure. In the past few weeks, we have typically been finding the inside temperature to be the same or only one or two degrees cooler than the outside. However, with all our new components, we are finding the inside of the house to be consistently five to ten degrees cooler than the surroundings!

Week 6

Our model home is officially done! We finished constructing the roof early last week and added a curtain to the door and louvres to the window on Friday. We have two thermometers that we will check periodically throughout the day to keep track of the temperature and humidity so that we will be able to compare our results to altered future versions of our structure.

We have left a few of the bricks unmortared and the roof is easily removable so that we can apply and test any new components we design into the existing structure without difficulty. Our group has kind of naturally split into groups so that some of us can work on the roof elements and others can work on alterations to the blocks and their configuration.

After some of the team had taken their vacation week, we all reconvened in New York City on Wednesday for a whirlwind day of taking in culture, exploring, and learning. We started the day at the new SUNY Downstate campus medical building, where we took a tour of the building under construction. It was really interesting to see what goes on behind the caution tape at a construction site and to get a close look at all the internal steps in the building process. 
After our tour, we visited the Ennead architecture firm office. They are the firm working on the SUNY building, so we were able to talk a little more about that building as well as other ongoing projects they’re working on. While it was cool to see the SUNY building, our main reason for visiting the office was to talk with one of the partners who had worked on a project building a school and community space in rural Zambia. She gave us a really nice presentation on the project and a lot of good insight on all the things that go into making a project like that possible. About halfway through our own project, this provided exactly the inspiration we needed to keep us motivated and excited. 
Next we headed to Little Senegal where we had a delicious, authentic meal and explored some of the local shops. It was nice to reminisce about our time in Senegal and to experience a little taste of the culture for our team members who were not on the trip. It was a great day packed with lots of fun and interesting activities. Today is our first day with the entire team here and we are feeling inspired and ready to keep working!

Week 5

We’ve made tremendous progress this past week. Thanks to Abby, we finally found a way to get our blocks to release smoothly from the mold by lining them with a thin layer of plexiglass. While this works really well, we decided to break down and buy premade concrete blocks so that we’d have more time to work on the more important stuff. However, we made a new custom mold with the plexiglass lining to make the smaller uniquely sized blocks we need for around the door and the window.

Our premade concrete blocks arrived last Monday, and already we are laying the final course of our structure. All of our smaller custom blocks have been cast and should be dry enough to use tomorrow. With the walls almost complete, all we really need to do is decide on how we want to attach our roof before we can start taking observations and measurements to compare to future models. 

At this point, we hope that each person will be able to develop their own idea that they can take the lead on in implementing into our existing structure or future structures, whether this be a new variation on the standard block or some other innovative component to incorporate into the walls, roof, window, or door. This is where all our early research will really help. We are having our weekly faculty dinner tonight to discuss our progress and where we would like to go next.

Week 4

With two new block molds ready to go, we started the week with high hopes. Because we’re constructing a fairly small building, we’ve decided to build two new molds at 75% the size of the original. We figured this would allow us to produce more blocks in less time, and at a more manageable size. After making some initial alterations to the new molds on Monday, we started laying our new blocks on Tuesday. Unfortunately we’ve since had a few setbacks since. While we’ve gotten pretty good at mixing the concrete, filling the molds, and flipping them, we’ve been having a lot of trouble with the release. The corners and insides of the blocks are not coming out cleanly.

After altering our mix ratios and varying how much we packed the molds and having little success, we decided to look into ways to facilitate the release of the concrete mix from the wood mold. The bad news is we still haven’t found the perfect solution. The good news is it has forced us to be pretty creative. So far we’ve tried spraying the mold with cooking spray, lining it with recycled plastic bags, brushing it with vegetable oil, and lining it with heavy duty aluminum foil. We may try vaseline, but based on the results using other oils, we are not too hopeful for this approach either. We would like to have a metal mold like they use in Senegal, but unfortunately these are not for sale and would take too much valuable time to make for just the control building. We are having a planning meeting tonight with our advisers to develop our next strategy.

On a more positive note, all of our group members are now woodshop and 3D printer certified as of this week. We have also had some downtime to start drawing and making small scale models for future projects to begin once the control building is built, like a miniature sandbag mock-up out of sand, balloons, and glue. Although we don’t have a ton to show from our work this week, we’ve definitely learned a lot and remain optimistic.

Check out Lehigh’s website for an article by Kelly Hochbein about our project! http://www1.lehigh.edu/news/better-buildings-senegal

Week 3

There was plenty to do this week! With all of our materials here and plenty of sun, we were able to start the heavy lifting. We spent the beginning of the week mixing concrete with different cement to sand to water ratios and then tested all of these ratios in smaller molds, so not to waste too much material. While ideally we would like to use as little cement and water as possible to make it most realistic for the Senegalese, we kept finding that the concrete blocks with lower ratios were not holding up well enough. Ultimately, we decided that we will use the same cement to sand ratio as they would in Senegal (about one to three), but we will be using slightly more water since the sand we are using is a little different. Since we are not specifically looking to change the materials of the blocks right now, we decided it is okay to alter the block composition to fit our needs even though it is not entirely accurate. We are still getting an authentic Senegalese experience by mixing all the materials by hand and laying the blocks in the hot mountaintop sun!
Once we had a rough idea of what ratios worked best, we started mixing larger quantities to fill our actual block mold. It took some trial and error trying to determine the best ways to pack and flip our blocks, but we now have some pretty good samples! After all of our experimentation, we are now looking into how we can alter our mold to make the process run more smoothly. We’re on the right track! We will continue making blocks and hopefully be able to start constructing something next week.

Week 2

We have received permission to start building and have marked off our designated site! We received a few bags of cement, lime and sand today as well as other necessary building supplies.  As soon as the rest of the materials arrive early next week, we will begin making blocks and constructing our model home. In the meantime, we have been researching possible directions we would like to explore once our control model is built. To maximize productivity, we split into two groups to look at different components.

One group has done comprehensive research on ventilation, looking into several ways they can modify the existing techniques to allow for more airflow. This is a vital and often lacking component to homes in Senegal, but poses a lot of potential issues. The goal is to create air circulation while preventing heat, bugs, and sand from entering the homes with the fresh air. Our first idea is to create all of the walls out of CMU, with a bottom row made of brise soleil blocks. We want to incorporate a type of screen mechanism in the brise soleil openings to prevent the entry of mosquitoes. The top of the building will have a row completely open brise soleil. There will be a barrier below that row which acts as a ventilation barrier and bug screen between the living space and the top of the house.  The top brise soleil blocks will be where most of the sunlight enters the house for visibility.

The big question of the week was Why do homes in Senegal not have screens when disease carrying mosquitoes are such a big issue? We came up with a few reasons, such as screens make the homes appear unwelcoming, they can easily damage in weather, or they are simply not cheap for people in Senegal to buy. We tried to experiment with different ways we could hide a mesh screen into a brise soleil block so it is not visible. Next week we want to explore different textiles people could use instead of metal to make it cheaper and easier to obtain for senegalese people. The 3D printing sustainable development group wants to work with us in the future and we are hoping to find a way we could 3D print screens with plastic made from recycled plastic bags.

We also experimented with different ventilation systems such as thermal chimneys and wind scoops. Thermal chimneys have a metal material on the top which attracts heat.  Below there is a corridor that allows air to rise and then funnel out of the building, circulating cooler air up through the house. The same concept can be applied to the south facing fall of a building. Heat is attracted to the metal wall and then a corridor helps funnel hot air up and out of the building. The corrugated metal roof is beneficial to these types of systems, instead of heating up the building to extreme temperatures like they are currently doing in Senegal.  Wind scoops can be used in multiple sides of the dwelling to help direct incoming winds through the space.

The other group continued researching earthbag construction and brainstormed how we could expand upon existing techniques being used in similar areas. A square or rectangular home constructed out of sandbags would look very similar to the existing concrete homes in Senegal once they had been covered in cement. The problem is that a rectangular structure typically needs wood frames distributed among the sandbags. Since wood is not widely available in Senegal, dome shaped structures would probably be a more viable solution. While these may provide different aesthetics, they also open up other opportunities for building.  

Since the dome shape tapers up to the top, one idea we had was to build a screen or some kind of low emissivity barrier into the sand bag layers towards the top and then leave the very top open. This way air would enter through the door and windows then the hot air would rise to the top and exit the building through the top. The screen would prevent bugs from coming in and then some kind of slightly elevated, removable or permanent cap could go on top to prevent rain and direct sunlight from entering. We could also easily incorporate a rain collecting device by adding a slanted ledge near the bottom of the dome that would collect the rain and siphon it into one area to be collected.

Another idea we looked into was incorporating sandbag homes into the traditional Senegalese compound and courtyard. One way this could be done is by creating one large, torus shaped building that housed a courtyard in the middle. Some things to consider are the fact that this type of building would probably require a separate roof and the shape of the building would not really allow for additional buildings to be added on to the compound as they typically are in Senegal. We also considered building lots of small domes and bridging them together as they get added on. This would allow for small corridors that could be treated as communal space and would also allow for an outdoor courtyard to develop naturally as it does with the current building techniques.

Ideally we would like to be able to construct two additional smaller scale models to test some of these ideas once our initial building is complete. Then we can compare them to see what is the most efficient building.

Week 1

The Summer team is off to a great start! Now that we have moved into our Mountaintop space in Launch Bay C, we have begun researching, brainstorming, and creating. Our preliminary work has included setup, planning, shop training, and familiarizing ourselves with our workspace and resources. With these initial steps out of the way, we can move on to our next phase.

After reviewing the raw data collected by the travel team, we determined that the main issues we want to explore are heat, ventilation, and sunlight in the homes. We will be keeping in mind cost, climate, and aesthetic value as we explore solutions to these issues. We may also explore finding a way to incorporate plastic into our design to help reduce the abundance of improperly disposed plastic waste found in Senegal.

Our first step will be constructing a 2m x 2m room made of concrete blocks with a corrugated steel roof, one window, and one door. This models a typical Senegalese living space and will be used as a control for comparing any new techniques we experiment with this summer. We have an initial list of materials we will need and some of our team members are already started constructing our block mold in the wood shop, so as soon as we get permission and have everything we need, we will begin constructing our Senegalese model.

We have also begun brainstorming and looking into possible techniques we might want to try or expand upon after we have completed our first model. We have considered rethinking the standard cmu block to incorporate a brise-soleil component in it. The advantages of this approach would be that it provides ventilation and airflow while obstructing direct sunlight. The cons would be that it allows for bugs and dust to enter the space, so we would have to figure out some kind of screen system to prevent this. 

Another technique we have researched is the use of earth bags for construction. This seems like a viable solution because sand is abundant in Senegal, so material cost would be very low. Sand also serves as a good insulator, so this could potentially keep the spaces cooler. These are still in the very early stages of the project, but we excited to start building and to see where our preliminary ideas take us!