Getting airflow in a studio apartment with one-window?
Sensing that this question may pertain to many others in various situations, I will give a response as follows:
We all know hot air rises.
Thus I would recommend getting two of the largest fans possible that would conveniently fit into your open window. Place the two fans into the same opening. The lower one should be place bringing the cooler outside air into your complex. Place the second fan as high as possible towards the ceiling.
Build a 2 by 4 square (rectangle) support between the two box fans. The 2 by 4 a square (rectangle) should be covered with thick plastic on both the inside and outside to help the hot outside air coming into the unit and allowing light to come in!
A window fan is a fan designed to be placed inside the frame of a window. Window fans have been used for many decades to maintain comfortable temperatures and ventilation within one's home, and operate at a tiny fraction of the cost of central air conditioning.
My windows will support a 20” fan.
Smaller windows can utilize smaller twin fans.
Two-fan (or “twin”) units feature two small side-by-side internal fans. They’re more compact, and while they offer a slightly lower airflow on average, two fans work more efficiently, cooling a room faster. Bonus: In a two-fan unit with electrical reversibility and independent control of the two fans via two intake/exhaust switches, you can have one fan perform intake and the other on exhaust simultaneously to maximize cooling efficiency and indoor comfort.
You can place the twin fans normally, on their side or even angled downwards, but supported, if your window is very small.
Also place wedges on the sides to help hold them in place.
We have both systems in our apartment because we do not have cross ventilation here and I feel uncomfortable having our door open.
Our fans are somewhat different from the images in this post, but you get the general idea.
During the hottest part of the day keep your windows closed and your blinds and/or curtains closed also. Curtains and blinds should also have a white backing to avoid absorbing more heat. I have dark heavy curtains which are back lined with an off-white backing. It works great at keeping the heat out. Not prefect, but it helps.
Fans blowing 24/7 will generally help. Stagnant air heats up terribly!
If you go the route of a portable air conditional unit, make sure it is big enough for your open square footage air space.