Manaus Housing Unit: Climate Simulation

Dear friends and family;

This is assignment 4 for my Systems Class. What you will see in this blog post is a result of 3 weeks of research and series of meetings with Mr. Field in order to figure out a reasonable design strategy- or at least to start to think about a good one.

As I said before, for this assignment I am taking a closer look on an independent research project I am developing, which is a housing unit for the Brazilian Amazon region. To see this project in detail click here: https://villeradieuse.wordpress.com/2011/10/24/assignment-4-outline/

Night time rendering - Victor Hugo Azevedo

It is a variation on a housing typology commonly found in the Brazilian Amazon, a series of houses built on stilts and normally over the rivers.

Vernacular (re)designed - Victor Hugo Azevedo

In regard to this assignment, my main goal with this project was to provide the maximum level of comfort to its dwellers without the use of electric energy ( air conditioners et cetera). Cities in this region of Brazil are highly air conditioner dependent and I am interested in developing new ways to deal with this issue. The weather in this region is normally really hot and humid, so what people normally do down there is to install airconditioners in their buildings and voila, problem solved. I don’t really buy that. I feel there must be a better way to do it.

It is important to acknowledge, though, that the notion of thermal comfort varies from culture to culture. What could  be normally a comfortable environment for a Brazilian like me may not be exactly ideal for an average suburban American. This is a really deeper topic and unfortunately I won’t have time to go into this for now. So for this project I decided to accept the software’s I’m working with default assumptions of « what comfort is ».

PART 1 – Studying the local weather. 

My first step in this project was to analyse the actual weather of the Amazon Basin Region. It’s true I had some basic assumptions of what it was; I knew it is hot and humid and that it rains a lot, but that was not enough. So I searched for weather data on Google and I found the specific EPW files for the city of Manaus, the city where this project would be located. Then I imported that imformation into the Ecotect software. This program has a really compelling thing called the Weather Tool, which basically analyses the EPW information I found and translate it into beautiful graphs.

So the most important think in this first part is the psychrometry. With the given information, the Weather tool constructs a psychrometric chart for the city of Manaus, and then tells me what the city actual conditions are and where the comfort zone would be. This is shown in the image below: The green-ish squares is the current situation of the city and the blue line is the ideal conditions for comfort.

Psychrometric Chart for Manaus

In this first one we can see that the temperature, in relation to comfort, is just about right; around 23-30 degrees celcius. What is wrong then? Yes, humidity. The humidity levels are way too high. So what you do to reach the comfort zone? You decrease the humidity!

Natural Ventilation Intervention

The Weather tool partly says what we have to do in order to increase the comfort zone. It gives us a series of alternatives, and the most reasonable one is Natural ventilation, (In red in the image above). So it’s not exactly a matter of getting rid of the humidity; or having the weather adapt to the building, it is instead a matter of the building mitigating the weather. And we can see in the image above that by means of natural ventilation the comfort zone increases just enough (red line) to encompass the majority of the Manaus Weather (in green).

After looking at all those psychrometric charts I thought: « well, I all have to do is to create a really open and well ventilated building! » It turns out that the the reality is far more complicated than what it seems. Little Victor was wrong. Let’s jump to part 2 and find out why.

PART 2Simulating trouble

Things were going well, I knew what to do and I was feeling optimistic. So I started to test out all the assumptions I’ve made. I made a couple of sections and simulated airflow through it using a software called TAS Ambiens. What I found out is that there was a direct correlation between the amount of air coming into the building and the average temperature in it. In order words, the more wind I was letting through the building the hotter and less comfortable it became. I recorded this simulation and the result can be seen in the following video uploaded to my Youtube channel:

In this simulation you can see how the hot and humid air enters the building and spread heat around the room. At this point I started to notice that something was wrong.What I realized is that the less air you let into the building the colder it would be. Why? Because the air is really hot!

I also created a 3d model on the Virtual Environment software in order to simulate these parameters tridimensionally. I have a couple of videos that depict how the cross ventilation would work inside the building’s rooms.

The results? Not very encouraging: No matter how open it was or how fast the wind was moving through the room, the comfort levels would just not go up. Very frustrating. I notice a clear disagreement between the weather tool and the climate simulation softwares. Is Natural ventilation not the right  solution for my problem? Well, in  my opinion, the question is still yes; I don’t think the psychrometric chart is completely wrong. It is a matter of design. Let’s move to part 3 and think about a this issue a little bit.

PART 3Response by design: Mission (Im)possible?

We finally got to the most difficult part  of the project; when the question is « what to do? ». Well, it is, indeed, a very good question. It is funny to see the degree to which we make so many wild assumptions for the building and don’t really test them. This housing project; the way it is would be a complete failure in terms of energy efficiency. The great merit of this fourth assignment was to let me test all the assumptions I had and to tell me that I was wrong; or at least partly wrong, because I do believe ventilation is the way to go. Some other things that might not be really successful is the inverted wing ceiling. In my mind it is there to increase the speed of the wind going through the building. But I am not convinced that it would actually work. The aerodynamics of this house is another issue I am interested in, but didn’t have the time to test. To finish it up, I think this assignment 4 was really enlightening for my career as an architecture student. After this I cannot imagine myself designing without first taking a look at the Ecotect weather tool and making weather simulations to test my assumptions in the early stages of design.

Special thanks to Bill Sherman and Eric Field.

-VH

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