How do you set up the simulation to cool your room without air conditioning?

How to set up the study to see if the box fan can cool your room and in which direction the air should flow.

Now that fall is upon us; I find myself leaving the windows open at night instead of using the air conditioning to keep my room cool.  Hopefully, I am not the only one, but I like having a window fan direct the cool ambient air into my room at night as well.  I just mentioned that the fan directs cool air into my room, but this is where the question is formed:  Which way should the fan face?

Does directing the cooler air into the room effectively cool the room quicker than directing the warmer air out?  I have always been one to point the fan into the room, but if you’re familiar with the second law of thermodynamics, you know heat travels from hot to cold.  So, if the “air” inside the room is naturally trying to escape to reach equilibrium, would it be more beneficial to point the fan out and aid in the natural thermodynamic property?

At this point, I was questioning my entire childhood about whether or not I pointed the fans in the right direction. This became extremely problematic. Well, not really, but it drove me nuts for a little while. I wanted to get to the bottom of this; as much as I wanted to test the idea, I had no tools or data collection methods to " real-world” test the problem. The one tool I do have is Flow Simulation. Let the modeling begin!

I don’t know the exact size of my room off the top of my head, but I looked up some approximate sizes and settled on a 15’x15’ room to keep it pretty generic. I extruded a box, shelled it out, and added my window cut. Check it out below.

I know what you’re saying, “Wow, that’s a beautiful room.”  Even though it’s entirely sarcastic, here is where the interior designer comes out in me.  I want to add some bedroom amenities and make it look like my own room.  This is not necessary for the Simulation but I want to make it look good while I am at it.  Where better to find modeled consumer products than 3D ContentCentral so I don’t have to design any of them?  Examining the SOLIDWORKS Task Pane, you will find the 3D ContentCentral plugin.

As you can see, they have folders for Categories, Suppliers, and even a User Library.  When looking for a specific component like a filter, pump, terminal, or anything of that nature, the Categories page is where you need to be.  If you always get your parts from a specific supplier, you can search through all of their components and download them directly to SOLIDWORKS.  Since I am not really looking for a category of parts (just some specific ones), I will go to the User Library and search for what I want.

As you can see below, my search for “bed” returned many hits. It's time to pick the one I want.

One great thing about 3D ContentCentral is that eDrawings is embedded into the web page for most models, so you can manipulate the part to make sure it is the one you want.  Check it out below.

Right next to the eDrawings window is the download options.  I just specified the file format and even the SOLIDWORKS Version I am using, and then it is ready to be downloaded.  Once downloaded, I can put the bed and other 3D ContentCentral components into my room.  Hopefully, it is more aesthetically pleasing now.

My bedroom is now modeled, the specs for the window are noted, and I can pass over my design with boundary conditions.  Let's run them in Flow Simulation and post the results in the upcoming blog.  Stay tuned for the outcome!