Cooling A Room

[artdutra04]

To truly solve this dilemma, you have to go back to the root of the problem. Your forced-air AC system is overstretched and the placement of the window in your room (it's probably facing south) are the sources of the problem.

Step 1: Prioritize which rooms really need AC:

Close the central air vents in either the coldest room in your house (by the virtue of forced-air HVAC systems, this most likely will be the room closest to the heater/AC unit.), or rooms that are seldom used (like those extra bathrooms, guest rooms, etc. that aren't really ever used) and don't need to be cooled. If these vents aren't adjustable, then take the vent cover off, put a piece of cardboard into the vent*, and put the vent cover back on.

If you don't need a room cooled/heated to perfect room temperature, then why pay for waste the energy to do so?

* With this method, you could always cut small holes into the cardboard to restrict airflow (as opposed to entirely stopping it), but the decrease in air entering that room should at least somewhat increase the airflow to your room.

EDIT: After just thinking about using cardboard for a moment, from a fireproof standpoint it would probably be better if you went to Home Depot or Lowes, bought a small sheet metal air duct plate, and using tin snips cut it down to size and used that behind the plate instead of cardboard.

Step 2: Eliminate possible sources of "wasted" AC:

Tint your windows/skylights with a light-blocking product. Leave the shades/blinds/etc closed. Glass acts like a greenhouse, so if you can stop the suns rays from entering the room, then you're less likely to have your AC wasted by the sun's radiant energy.


For bonus points, both of these solutions have the potential to not only save you money in the long run on utility bills, but they're also green, environmentally-friendly solutions. It's win-win.


// Me thinks I've spent too much time working on houses...

[RyanN]

Originally Posted by Pavan

In my house, my room is the only one that does not get its share of cool air when the AC is turned on. After having a professional look at it, he said something about the position of my window towards the sun as well as the fact that my room is the last on the line to get the cool air.

My father said that he is up for me figuring out some way to cool my room. Without buying an external AC unit [that hangs out of my window] I was wondering if anybody has any ideas or knows anything about this type of stuff so that I can mod my room? Any ideas or suggestions would be appreciated because I have no idea where to start for my research except off of others' (who have some knowledge possibly about this field) knowledge.

Thanks for your help,
Pavan Dave.

(PS. If you think it gets hot where you're from, please visit Houston in the summer and I don't think I'll have to say a word, )

I have the same problem, except I'm the first in line for the air conditioner, but I run a server 24/7 that has a warm exhaust and the house is pretty well insulated, so my room keeps in the heat, and the rest of the house keeps the cold air, which means that our A/C doesn't run very much, making my problem much worse. At times, my room gets up to 87 degrees, which really sucks. I usually take my laptop and go into the living room. I guess the easiest solution I could think of is getting a fan that blows air out of your room through a window, that way more cool air enters your room. Another idea is to partially close other vents in the house to give you more air flow. I've been thinking of getting our small windows A/C that is in my workshop not being used and putting it in my room's window and leave it on low. My room is the hottest in the morning (since the A/C usually doesn't run much at night and my server is still running). When I get it, it is usually 82 in my room. If I'm playing games on my server my room gets very warm, and my laptop also heats up my room after a long day of playing games or something.

[Not2B]

Mmmm...

2 main things to do.
1) Reduce heat energy from entering
2) Remove heat energy

Window films will cut the sun load. (And in Texas in summer, I'm guessing you are close to 1000 watts/m2.)

Powered vent fans will help pull in cold air (remove heat). OR - if you find the return vents, fans going the other way will remove hot air (remove heat).

Insulate your room to the outside. (reduce heat from entering.)

You live in Texas. It gets humid I assume. The swamp cooler (evaporative cooler) might not be a good idea, since it requires a dryer air to really work well.

The peltier effect is really awesome and fun, but probably not a good solution for this. The average store TED (thermal electric device) is about 40 watts. A human at rest, on average, gives off 100 watts. PLUS - if you remove 40 watts from one side, the hot side has to get rid of 40 watts plus the power used to run it (lets say about 80 watts), for a total of 120 watts. Now you have a HUGE problem getting rid of all that power. And don't get me started on the tiny Delta T.... (I spent about 2 years doing research on these things. They are AWESOME, for the right application.)

And before anyone says plug in a fridge and open the door, remember that will heat the room up. It's all energy. Learn as much as as you can about energy, and you'll come up with some cool ideas. (Pun intendent.)

Good Luck!

[Pavan Dave]

Thanks for the ideas. Jacob and I have been discussing this for about an hour to two hours tonight and tomorrow I will try to make a cooling fan similar to the ones suggested in the earlier posts. This of course will be a short term solution. Also I am looking into possible shades to put outside my window like some sort of tree or a large screen of some sort to put inside.. For the long run I will suggest prioritizing the vents and possibly looking into some thermoelectric technology (Click Here).

The project, which is expected complete by the end of this Saturday, is to coil some copper tubing around one of my current oscillating fans and to pump cold water through it, and hopefully through the use of ice packs keep a steady supply of cool air in my room.

Thanks for the ideas guys, and keep the coming. Many of you have very good ideas. Chief Delphi's 5000W think tank is running at full blast and the to think that the season has been over for nearly a month.

Peace.
Pavan

[Michael Coleman]

1. Leave the door to your room open if your room does not have a dedicated A/C return vent.
2. Adjust A/C exhaust vents in all rooms to provide appropriate airflow.
3. Check the A/C ducting to assure that it hasn't "collapsed" or is otherwise obstructing airflow.
4. Are the coils in the air handler clean?
5. Is the air filter clean?
6. Install a ceiling fan.
7. Install a thermal barrier on the window (reflective film, curtains, etc.)
8. Check the insulation in the attic over your room.
9. Install an attic fan to remove warm air from the attic.
10. Check ducting for air leaks.

[EricVanWyk]

The biggest heat source in my room is my computer. Quick and easy way to remove a few hundred watts: Turn it off.

The biggest question: Do you want cool or cool? IE are you going for the wow factor or for the sweat reduction factor. There is a lot of fun stuff you can do for this, but none of it is going to come close to redirecting the A/C and removing heat sources.

[indieFan]

Double check that the ceiling fan is turning in the correct direction. It won't solve the entire problem, but it might help a bit if it isn't going in the correct direction right now. To cool off a room, you want the lower edge of the fan blades to be the leading edge. That way, they are pulling the hot air up. When the weather is cold, you want the higher edge of the blades to be the leading edge. That way they will be pushing the warmer air down.

I learned this after years of living in SoCal with a room that faced west and a mother that didn't like running the AC at night.

indieFan

[cire]

I used to have the exact same problem, my solution was to move to the basement. Later on i moved back up and i just used fans religiously. I also ahd a problem in the winter where it would be too cold in my room, so i used blankets

[KTorak]

Here is a homemade AC unit I looked into making last summer. My house lacks central AC and we have no windows in our basement for AC. Therefore my room gets really warm during the summer.

[Bill Moore]

Originally Posted by Alan Anderson

It sounds like you have two directions at which you can attack the problem. First, do something about the heat entering your room through the window. One of the best solutions is to use a deciduous tree to shade it, so the leaves are only blocking the heat in the summer. There are also metallized plastic films that you can put on the outside of the glass. Be wary of using shades on the inside of the window, as they'll mostly end up trapping the heat and radiating it to the inside anyway.

Second, you want to get some air moving. A ceiling fan will help dramatically, as will "booster" fans in the ductwork. If you can force the air inside your room to mix with the air in the rest of the house, you'll be able to keep the temperatures more consistent.

YES!!!! Increasing A/C to your room only deals with a SYMPTOM of the problem, whereas Engineering should consider the CAUSE and deal with it first, if possible!

Your window may be the most thermally transparent item on that wall, but the whole wall is transferring heat into your room. By shading the wall, so that the direct sunlight is deflected, you will lower the outside temperature of that wall by 10 or 20 degrees -- a direct reduction of heat transfer. A deciduous tree is a good long term solution, but for a quick term one, erect a large trellis along the wall and plant a quick growing vine to shade it as much as possible. All that photosynthesis you learned about in biology will transfer the suns energy into plant tissue rather than heat in your room. (I suggest Moonflowers, which will perfume the evening air if it cools down enough to open your window at night.)

Once you deal with the heat entering your room, then you can consider additional measures to increase A/C flow to your room. Otherwise, you are just increasing the bill you pay to the energy company.

Proper Engineering considers the "system-wide" problem when brainstorming a solution, rather than focusing on the one specific affected component.

[Mike Bortfeldt]

Pavan,

Two years ago I had similar problems with both the heating & cooling in my house. In the summertime, the AC would cool the 1st floor fine, but the 2nd floor (where the bedrooms are) was always much warmer. The same was true in the winter (only reversed). One difference from your problem was if I had a fan in the bedroom circulating the air, then the AC would actually cool the room fine. It stayed hot when the only air circulation was the furnace blower. After doing a little research, I made the following changes (I'll include the heating changes in case anyone is interested). I’m not sure if any of these are applicable to you, but hopefully you might get some ideas.

1) The ductwork in my house mainly runs through (what should be) an unheated/cooled area of the house (basement) so I insulated all the supply ducting in this area. I also located and fixed any leaks within the ductwork itself in these areas. This all by itself resulted in a noticeable change in the basement temperature as I was not accidentally heating it in winter or cooling it in summer as much.

2) I read online (I can't at the moment find the website) that air conditioning requires more airflow than heating for it to work efficiently. If yours is an older house that was not originally designed for air conditioning, it may have grilles (vents) with slits that are too small and restrict airflow too much. I replaced all the room vents with new ones with larger openings that also allowed me to direct the air toward the center of the room rather than having the vent scatter the air off to the sides or straight up. This change eliminated the need for a separate fan in the bedrooms to circulate the air, as the furnace blower now was able to circulate the air within the room without any assistance. It also help direct the air out into the room when the vent was under a desk or otherwise somewhat obstructed. This does result in more “drafts” when the blower is running, but overall it is worth it in my opinion.

3) Originally all the return air vents were at the baseboard level. This worked fine for heating, but efficient air conditioning requires the return vents to be mounted near the ceiling to allow the warmer air to removed from the room. I added additional return vents at ceiling level above the existing ones using the wall cavity between the studs as the ductwork. I also replaced all the return vents with ones that can be closed, so that in the summer time, the upper ones are open, and in the winter, the lower ones are.

4) As others have mentioned, adjust the dampers on all the individual ducts to even out the heating/cooling throughout the house.

5) Keep a clean filter in the unit to keep the airflow as high as possible.

6) For heating, my furnace has a delay between shutting off the natural gas and when the blower shuts down. This was originally set to 30 seconds. I increased this to 150 seconds to transfer more of the remaining heat from the heat exchanger and ductwork into the living areas of the house (unfortunately this doesn’t work when in the cooling mode)

7) Replaced the thermostat with one that allowed me to set deadband for turning the heating/cooling on/off. I increased this value, which reduced the cycling of the furnace.

8) Add plastic to some of the larger windows (or ones that don't seal as well as they should). Hot air rises, so to some extent it doesn't matter where the hot air enters the house, it will work it's way up.

9) If you have an attic above your room, make sure you have sufficient insulation. Add a temperature-controlled fan to the attic area to remove the hot air. It's not uncommon to have an attic that is 20-30+ degrees hotter than the outside temperature.

10) Restricted the air return on the vents closest to the furnace to try to draw more air from the rooms farther away.

These changes significantly increased the efficiency of the heating/cooling. Before, on a hot summer day, the AC would not be able to keep up and the house would slowly get warmer (the whole system is probably a little undersized), now not only does it keep up, but it can cool it down. It also reduced energy consumption by over 20% as well as making the entire house more comfortable.

Mike

[Tristan Lall]

Depending on how easy it is to access the ductwork itself, it's quite possible to also affect the rest of the system, without increasing energy consumption.

If you can get at any of the ducting in the house, take a look to see if the seams are taped (using real duct tape—the aluminum stuff), and the ducting is the correct shape and kind (e.g. sheet-steel hard ducts are common). If the builder used flexible ducts, or has panel gaps in the rectangular ducting (round ones interlock, but most custom rectangular ones don't), then you want to tape them off. Any air escaping into the spaces between floor joists or wall studs will eventually get around to cooling something, but for your purposes it's clearly wasted. In some cases, the improvement can be up to 10-15 cfm, between a bad installation and a good one. Of course, if this involves breaking drywall, it might not be practical.

Also, check your return air system. If the static pressure in the room is too high (e.g. your door is closed, and air coming in has nowhere to go), the airflow in will diminish. Especially if your house is well-sealed against air infiltration though walls and windows (this is a good thing), you'll want to makes sure that your return air ducts are clear, and the right size. Unfortunately, it's not uncommon for returns to be pulled out and forgotten during renovations.

[Qbranch]

As a followup, I did some research on the idea of the Thermoelectric air conditioner... For a home user, or anyone with a head between their shoulders, a 6000+ BTU moving-parts-free near-silent air conditioner is out of the question. However, a personal portable air conditioner could run for about 2 hours off of an MK-12 and produce about 1000BTU/h of cold air.

Anyhow, here's my ridiculous research on my doomed 6000+BTU/h peltier effect air conditioner:

Thermoelectric Air Conditioner Project Notebook

Desired:

6000+ BTU Thermoelectric Air Conditioner with Near Silent operation and minimization of Moving parts. There are 3.41 BTU/h in one watt.

PartsList:

> 22 - "PJT-7" 40x44mm (1.57x1.73") Peltier Junction Array, 80.6W each. @ $14.75/ea, AllElectronics.com
	-whole array size @ 6x4, 9.45x6.93"
> Plywood or MDF for Enclosure @ Free~$10
> ProPink Rigid Foam Insulation (http://owenscorning.com/around/insulation/products/propinkrigid.asp) @ $Free~7
> 4 - (2 per side) Antec TriCool 120mm DBB Fan available Fry's @ $12.99/ea
> 18 - (9 per side) Heavy Duty Aluminum Heatsink Trapezoid 4x2.5x2.25" @ $3/ea
> Cosel Modular Power Supply, 3200W, (http://www.trcelectronics.com/Cosel/modular-power-supply-max.shtml) @ $1500/ea

>Grand Total Cost (Maximum)
	- $1976.96 (add in random stuff, probably $2050)

Power Requirements:
> @12VDC, each junction package requres 6.71(6repeating) amps
	- Total Junction Ampereage: 161.19999A
	- Total Junction Wattage: 1,934.4W
> @12VDC, each fan requires 250ma
	- Total Air Handling Ampereage: 1A
	- Total Air Handling Wattage: 12W
> Grand Total
	- Total Air Conditioner Watts: 1,946.4W
	- Total Amps @ 12VDC: 162.2A
	- Total Cooling Capcity: 6,596.304BTU/h

Conclusion:
	> While a giant near 7000 BTU near silent Peltier cooler like this is an extremely impractical idea, 
(now apparent to me), a scaled down model of this, perhaps a 3000 btu model, would cost $300 approximately,
 much more in the range for an air conditioner in power requrements as well as cost. Also, a portable conditioner 
would be a much easier feat, at around 1000 btu, most likely with a cost of $100 and the ability to be carried around 
portably... if you don't mind lugging along an MK-12 :o ... but thats what wagons are for!

Well, try not to laugh too hard...

But I still think i'll try the personal walkabout air conditioner, sounds like a good thing for a hot indiana summer.
-q

[vivek16]

crawl into the ducts and rearrange it so your room is one of the first in like

[Pavan Dave]

So apparently after much debate with my father, my room is NOT the last in line for AC but our AC "equally vents to every room." That said, he told me it is the sun's fault and the people who built our house for putting the window where they did. After linking him to the websites with the 3M window screens as a permanent solution, he has agreed with me that that is the best solution to fix this problem. In the mean time, I was able to spend a good forty dollars today and make an awesome air conditioning unit out of my fan that actually works. Here are some pictures taken from my camera phone:






MATERIALS Purchased:
10' Soft Copper 1/4 OD
10' Vinyl Tubing 3/8 OD | 1/4 ID
6" Vinyl Tubing 1/2 OD | 3/8 ID
1 Mini Tabletop Pump (for small fountains)
500 Pack of Zip Ties

MATERIALS Savaged:
1 14" Diameter Standing Fan
1 Coleman Personal 16 Cooler

Facebook Album Link (A Facebook account is not necessary to view this album).

Peace.
Pavan.