Cooling A Room

[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.

[dtengineering]

Well, it sounds like this one is well on its way to being solved. But why not throw in another option...

Growing up in northern BC, I had the exact opposite problem... my room was in the basement and it was too cold. Just to clarify... in the deepest, darkest, depths of winter we would have 1/4" or more of frost in some locations on the INSIDE of the house. (specifically a small location on the north side where the floor joists met the wall and the insulation was thin... it wasn't a complete igloo...) Unlike the multi-server set ups discussed here that might have helped warm the room, my Commodore 64 wasn't exactly dumping a lot of waste thermal energy.

Of course the issue wasn't that the room was too cold... the issue was that I was too cold (the room, really, didn't care what the temperature was).

The solution was to get a waterbed. It was always cozy warm when I went to bed, and not only would it keep me warm in winter, but it was cool in summer. The normal temperature for a waterbed is 28-30 degrees celsius, so unless your room exceeds that temperature on an average basis, you probably won't even need to cool the bed.... which you can do with just a bit of tap water if you need to.

It won't be much help when you're sitting in front of the computer on a hot afternoon, but at least it will help you sleep at night.

Stay cool,

Jason

P.S. Do you have a CRT monitor in your room? This would be a GREAT excuse to get an LCD... and Core2Duos are known for being energy efficient...


P.P.S. The winters in Dawson Creek (my hometown) have been, on average, much warmer over the past couple decades. Even back in the 80's I did a science fair project showing that the winters were warming and snowfall was reducing. Now, due to warm winters across northern BC the Mountain Pine Beetle (which needs three weeks below -30 degrees to kill it) is enjoying exponential growth, devastating huge areas of forest. Anyone who doubts global warming is welcome to drive through the centre of the province and check out all the red, dead trees. So I'm really pleased to see that everyone is suggesting energy/carbon efficient solutions here.

[Dick Linn]

I once had a brick house where the bedroom wall was exposed to the sun nearly all day. I would hose that side down in the late afternoon to cool it off. I was going to build an arbor and plant some vines on it, but I moved before that happened.

You already have good advice on airflow and insulation.

[Chris Fultz]

some simple steps -

be sure the air inlet has a clear path (no furniture, clothes, chairs, etc blocking the path.

be sure there is an air return path. if there is not a return in your room -
either keep the door open, or install a return.

if the air return is in the hallway (common) - add a vent above your door into the hall. this can be pretty simple - cut a hole in the drywall on both sides and just install grilles over the cut-outs. you can do this for less then $20.

for the cool air to come in, the warm air has to get out.

* this is why a lot of very old, high ceiling homes have small "windows" above the doors. these could be opened to allow air to circulate through all of the rooms, even with doors closed. i will remember what they are called at some point.

[whytheheckme]

I live in CT, so I have nothing to talk about.

But, here is what I do:

I have a cubicle inside my room. (I need to keep the servers inside COOL.... I run the robotics website off of one, my personal site off of another, plus some file servers, my gaming machine, my CD-SPY machine, my two work machines, my IM machine...just to name a few). The cubicle is sealed, including the top (it is under my loft). I have a window unit (not designed for my windows... my windows does not open vertically... it opens horizontally, so I made a cardboard cutout for it... I'm not too worried about my room getting hot). I made (out of cardboard) an adapter that is duct taped onto the front of the unit that adapts to a 7" round aluminum flexible duct. I calculated the size of the duct based on the area of the output vents on the air conditioner. The flexible duct runs across my room (at about hip height, just tall enough so you can't possibly step over it, but just low enough that you cant go under it... how convenient) to my cubicle. I cut a hole in the side of the cubicle and duct taped it in. Inside I have a piece of printer paper (my final physics exam cheat sheet) with a piece of duct tape on one side. I can tape the paper to any side of the round duct to deflect cool air onto me regardless of where I am sitting inside. I have a thermometer (indoor/outdoor) inside so that I can see the temperature difference. I also have an electric meter inline so I can tell how much juice I am sucking.

Now this sol'n requires a window unit. My grandmother has an A/C unit that is upright, and is on wheels, so that it can be moved from room to room. The unit is about 3.5 feet tall (hip height maybe). It has a tube (looks like a dryer vent) coming out of the back with a little plate adapter to go into your window. This is so that you don't need to lift the unit into the window, and you don't have an ugly unit sticking out (just a small white plate with the vent).

Now for the 5 dollar solution (probably more like 20)... Take your regular oscillating fan, make a coil of copper tubing around the back, attach the tubing to a aquarium pump, and into a garbage can of ice water. Pump the freezing water through the coil so that the fan sucks the air over the cold coil and cools it. You need to keep changing the water (adding ice), but if you have an automatic ice maker, this isn't a big deal (yeah right.)

That's my input.

Jacob

[Alan Anderson]

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.

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.

[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...

[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

[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

[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.

[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.

[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.