Anything better than bldc ceiling fans for cooling? (cant afford ac)

[6pack]

I don't know why it's so hot in October now, but the bldc ceiling fan just isn't enough even at speed 6. It just keeps pushing hot air though out the room with window and door open.
Does a tower fan push more air than a ceiling fan? I've seen youtube videos and i came to know, even it pushes hot air from back to front. Current humidity is like 75% and 30C inside the house 24hours. Must be hotter outside even at night.

anyway to cool off without ac? or force air through the room so it does not get stagnant? weird thing is, if i keep the window open, the fans air seems to disappear somehow. seems to go out the window. if i keep the curtain closed a bit, i can feel the air from the fan but it gets hot fast. If i close the window, the room feels like an oven.

 

[n1r0]

or force air through the room so it does not get stagnant?

Exhaust fan on the window? Try turning it around and using as intake as well

 

[BullettuPaandi]

if i keep the window open, the fans air seems to disappear somehow

Judging by this, there's probably more pressure in than out- meaning you might have more air entering the house than leaving. So, ideally you'd want to keep the window open for ventilation. But this doesn't necessarily help with cooling. So, best bet without AC is to use an Air Cooler - basically a tower fan that pumps water through a cardboard behind it. Using just this would also eliminate heat that the ceiling fan would bring in from the top, especially if you don't have a construction above - an apartment, a room, attic, etc.

 

[TEUser2K1]

Does fan's fixing / placement also matter ?
Air cooler suites places where humidity is very low, i.e., dry heat ?

Wondering whether there are peltier cooler based diy air conditioners by hobbyists.

 

[n1r0]

Wondering whether there are peltier cooler based diy air conditioners by hobbyists.

They are very inefficient for cooling. Even a peltier CPU cooler would consume too much power and produce additional heat. This the reason you can't cool a room by keeping the fridge door open. The hot air has nowhere to go. Also AC would be cheaper to run than peltiers

 

[BullettuPaandi]

Air cooler suites places where humidity is very low

Yes. It's only effective when combined with proper ventilation, especially so in those places. Without a controlled environment, like AC in a closed room, proper ventilation is a must for any solution to be effective.

Even a peltier CPU cooler would consume too much power and produce additional heat.

Yeah, even assuming some clever engineering for dissipating the excess heat produced, drawing heat from air in the room is much more harder than from the metal surface of the CPU.

 

[TEUser2K1]

Only need to keep temperature between 25-28C.
When checked in internet, there seems to be some industrial solutions based on thermoelectric cooling, costly though.
Not having lot of moving components requiring power, not having to use environmentally harmful gases, etc. can be a huge positive, if efficient ones are researched and proved.

 

[n1r0]

...drawing heat from air in the room is much more harder than from the metal surface of the CPU.

In most cases the best way to cool is bringing in cool ambient air, else you can exhaust hot interior air. AC is need when the ambient air itself is hot

 

[Emperor]

Exhaust fan on the window? Try turning it around and using as intake as well

@6pack fixed Heavy Duty Exhaust fan (Unique Brand Fan.. using in Room since Year 2000), not that fancy type, that open front shutter when fan is ON and shut down shutter when fan is OFF.

Just make arrangement like Computer Cabinet, intake from any one but GOOD FRESH AIR area/side and throw all inside HOT air out from other or exactly opposite side. Make sure that except exhaust fan bled area NOTHING SHOULD keep open as it very badly affect working of Exhaust Fan and thus less cooling.

Also make sure that near by Air Intake Area there is NO AC Outlet from any fellow flat owners, else your Exhaust Fan will pull all HOT AIR from their AC Outlet & fill your room with HOT AIR

 

[BullettuPaandi]

In most cases the best way to cool is bringing in cool ambient air, else you can exhaust hot interior air. AC is need when the ambient air itself is hot

Sorry, I don't understand what you're trying to say.

 

[n1r0]

Sorry, I don't understand what you're trying to say.

Something like this will bring in fresh air from outside OR exhaust hot air from inside depending how you install it. If ceiling fan alone is not helping, this might help by increasing airflow.

Imagine you are a PC component sitting inside a hot cabinet. What do the intake/exhaust fans do?

But if the ambient air outside is too hot like in summer or too humid, no fan can help you, only AC can cool you down. Things that make you feel less hot:

• Air speed: at any temperature, faster the airflow, cooler you will feel
• Pumping IN cooler air from outside (pushes hot air out from other openings)
• Pumping OUT hot air from inside (pulls fresh air in from other openings)
• AC: no airflow required. Works in any situation

 

[BullettuPaandi]

drawing heat from air in the room is much more harder than from the metal surface of the CPU.

Ok, here I was just comparing thermal conductivity of air to that of metal, to say that if thermoelectric cooling is power hungry to draw heat away from a metal, it'll only be even more so to draw heat away from air.

Things that make you feel less hot:

You're totally right on the first one, because more airflow helps evaporate sweat faster, thereby making us feel cool. Although, 2nd & 3rd require some clarification. Pressure is a key difference in ideal conditions in the comparison between room and PC cabinet.

Say we only pump cool air in; we'd rise the humidity, hindering sweat evaporation. So we won't feel cool; only sticky.
But, only pumping hot air out would work, especially if it's a large room. Air that'd enter the room usually through a small window or door, due to negative pressure inside the room, would have more room to expand, dropping the temperature down. But, we might want some fast moving air near us to help in evaporating our sweat.

So, unlike in PC, where positive pressure is usually advised to keep dust out, negative pressure is what we want.

 

[n1r0]

drawing heat from air in the room is much more harder than from the metal surface of the CPU.
Ok, here I was just comparing thermal conductivity of air to that of metal, to say that if thermoelectric cooling is power hungry to draw heat away from a metal, it'll only be even more so to draw heat away from air.

Ah I see what you meant now. You don't actually need to cool down the hot AIR inside the room - you can simply replace it with cooler air from outside. That will have the same effect as cooling the inside air, but consume less energy since you're moving air instead of actually absorbing the heat to cool it down.

Air that'd enter the room usually through a small window or door, due to negative pressure inside the room, would have more room to expand, dropping the temperature down.

Umm, I think you're comparing to how refigerants in AC expands and cools down. This isn't what's happening with air inside/outside a cabinet/room.

So, unlike in PC, where positive pressure is usually advised to keep dust out, negative pressure is what we want.

As long as you're getting fresh airflow, it doesn't matter whether it's due to positive or negative pressure gradient.

TLDR: Replacing hot air with cool air from outside is cheaper than actually trying to cool down the warm air inside

 

[BullettuPaandi]

cooler air from outside

True, but it's not always a given that outside air is cool, while inside is hot.

This isn't what's happening with air inside/outside a cabinet/room.

That's exactly what's happening bro. Temperature drops as volume is increased; gas molecules have more room to move around.

it doesn't matter whether it's due to positive or negative pressure gradient.

So, it does matter. Not talking about it's gradient, just pressure in general.

Edit - You may have noticed exhaust fans mounted on top of the roof in some buildings. All they do is move warm air, which is less dense, out.

 

[n1r0]

That's exactly what's happening bro. Temperature drops as volume is increased; gas molecules have more room to move around.

While wind does blow from a region of high pressure to a region of low pressure, natural atmospheric pressure variation isn't enough to cause any noticeable cooling effect when air flows through big openings like windows/vents. Ask yourself this: why do cars have an AC compressor when they can just put holes in the glass. The air pressure on the glass is quite high at highway speeds, so the cooling would be quite substantial inside.
You should look up the values for atmospheric pressure and AC compressor high side pressure. I'm not saying you're wrong, I'm saying the effect is insignificant in the way that your weight decreases when you exhale and your lungs are empty.
More importantly, where did the heat from the incoming air go? Remember energy can neither be created nor destroyed. In AC the cooling inside the room happens due to evaporation of the liquid refrigerant, which is then condensed outside by the compressor and cooled in the radiator.

 

[BullettuPaandi]

Not sure if it's still natural atmospheric pressure variation, when we can moderate it. But, what you're referring to is in fact enough to achieve noticeable cooling effect. You can see this implemented most old-school buildings that have just the main hall's ceiling high-rised with windows at either directions of the wind. You can look up 'stack ventilation'.

Ask yourself this: why do cars have an AC compressor when they can just put holes in the glass.

Two things - First, not just cars, ACs in general have compressors to pump the refrigerant through the system. Secondly, why not have holes in the glass (I'm assuming that you're referring to one in the front, windshield) a component that provides structural integrity is pretty much self explanatory. There are, however, vents just below the windshield that does bring air into the cabin.

The air pressure on the glass is quite high at highway speeds, so the cooling would be quite substantial inside.

You're confusing pressure, a property of air by itself, with pressure exerted by the air on a collision with a surface. I mean, you said it yourself - "The air pressure ON the glass". But there is a high pressure zone in front of the car and it does enter the cabin via said vents. In the ventilation that we're talking about, there's no air against a surface. The wind passing above the building through a roof exhaust or the high-rised windows in the old-school buildings example, would basically suck fresh air in from wherever the vent/window is desinged to be. Since you seem to be familiar with automobiles, it's sort of analogous to the venturi effect in carburetors.

More importantly, where did the heat from the incoming air go?

It is dispersed into a larger area.

 

[Tarantula]

Imagine you are a PC component sitting inside a hot cabinet.

That is an excellent analogy, for the kind of members this forum has!

My solution to the original poster's problem is to install a desert-cooler at the window of his room, and seal the gaps between the two. Then run it while keeping your door open. This works best when the humidity outside is low.