Portable Energy Device that can power a home

[Rabid]

Several point :

First, if it is not the case already, install external shutters on your windows to block the sun from entering into you room. If you do it right, you will still have enough penumbra to see clearly inside, but you will receive far less heat (and anyway, a light bulb use much less electricity than an AC). Our climate back home is clearly not tropical, but temperatures over 30 °c is the norm here during summer, and we can manage without AC just good with only good insulation (double glazing) and closed shutters.

Segundo, setting your AC to 17 °c is basically useless, even more so if you do that in a room you are not in. Cease doing that and you'll already save a good amount of energy. What you can do is setting your AC to 23 °c half-an-hour before going to sleep. If you have a timer/plug programmer, you could even tell it to shut the AC off 3 hours after your going-to-bed time. You can also tell it to run only 1 hour every 2 hours, or something like that. Thermal inertia while see it to you not feeling too much differences.

23 °c is comfortable, but you can manage with 25 °c. It is still comfortable, but you'll use far less energy in the process (I guess a bit more than 10%).


One way or another, you'll have to suck it up, and AC is the first thing that should go, as it is basically just a "comfort" thing, not really necessary unless you have some medical condition. Anyway, you'll save far more energy -and money- in the long term by insulating your home than by installing expensive solar panels or by buying a gas generator.

The question, though, is : do you have competent (and relatively honest) artisans back in Venezuela willing and able to correctly insulate a flat with the benefits of all the modern techniques ? 'Cause the risk of insulating a home is that, if you don't do it right, the air stop circulating, and all the humidity and staled air stay inside, forcing people to open their windows if they want to keep breathing, and thus defeating the whole purpose of insulating ones home.


You should seriously look into insulating your home. That's currently your best bet, energy-saving wise.

[Rabid]

Ghetto edit :

Also, for the walls directly exposed to the sun, I present to you External Insulation :

173 Kilobyte jpeg image

[LaCroix]

Sounds to me that the wall is your primary problem. From your description, it is a bare concrete wall, with maybe white paint on the outside. I guess you wouldn't hose it down otherwise - which you SHOULD NOT DO if you value the wall's integrity.

So your best bet would be proper insulation. Which would be beneficial in the way, that is a one-time, low cost investment that will yield long-term saving, with no concurrent cost.

The easiest way would be heat reflective paint, or putting up styrofoam insulation (with plaster rendering), which should remove 60-80% of the heat buildup.

The paint is the easiest option if you don't own the house, as its only painting the wall, which the house owner usually doesn't have a problem with, and even if, you can hide it pretty well by choosing the right color.

Optimal solution - add styrofoam/foil insulation to the wall, render with plaster, and then put heat reflective paint on that. 90-95% heat transfer reduction.

Damnit - ninjaed by Rabid...

[Lord Baal]

Thanks to both of you. I will try to keep your energy tips rabid.

As for the wall, yes it's painted but I don't think that is a reflective paint. Other wise I wouldn't soak it! The trouble with this is that it's right on the public sidewalk to enter the building, so I'll have to ask if I can put the insulation and if not then if I can paint it on reflective paint that matches the color of the building. I'm tempted to take some pictures so you could get a better picture if you want to.

[Hamstray]

This could be a not so environment friendly solution, but gasoline costs here are in the range of 0,07 or 0,14 bolivars per litter, or about 0,01 or 0,02 dollars (1 or 2 cents) per litter (its used as the bread and circus or the opium here). Problem comes when I think on how to store safely enough gas. A barrel contains about 160 liters (about 42 gallons), if I'm to using it up 5 gallons (10) hours per day it will last about 8 days, and cost me about 12.8 bucks or 55.4 bolivares, way less than the 400 bolivares fines I'm getting right now..

Incredible. The global price of gasoline is somewhere around $0.8 per liter or $125 dollars per barrel. (http://www.indexmundi.com/commodities/? ... y=gasoline)

[Lord Zentei]

Well, they do produce the stuff over there, and are probably making it available at below what would be the normal price as a populist measure.

[Lord Baal]

Bulls eyes Zentei. Lately, out of incompetence, our own refineries are being incapable of refining enough fuel, so we are now importing gasoline from Brazil. Said gas is sold at the same prices as the local produced to avoid the massive riots that had occurred every time the price of gas is adjusted even a little. We haven't seen a considerable change on it's price from a long time now, even when our economy have the highest inflation on South America (and I think that on the whole American continent).

[madd0ct0r]

ok. Rabid speaks wisely.

I might echo some of his points here – if I repeat them, it's cos I think they're that important.
I'd also be wary of dropping your electricity consumption too much – if you do get down to 500kwh, then next year will they fine you if you go over 500?

Still, as a general rule, being comfortable with less is a good thing. Lots of good basic stuff here: ttp://www.puravidasunsets.com/green-building-tour.html

The A/C is clearly the energy hog, with the TV's and probably the computer close behind (they also output a lot of heat, which means more electricity needed for the AC, so you pay twice). I assume you're turning the tv's, computer, monitor ect off at the socket? Plasma screens use a lot even in standby mode. As for storage mechanisims, if the brown outs are for only a few hours, aim for enough for lighting. If they're longer, aim for enough to keep the fridge and freezer going. You can get battery powered fans/lights here, I'd assume the same is true for you. In a power cut, sod the air conditioning. Some things just ain't worth it.

so, a high humidity tropical climate, no heating required, summer cooling required.
I live in central Vietnam, I feel your pain brother.

For the Canadians reading shocked at what I call 'cool and cold' please remember I live in the tropics. My house has no heating, little thermal mass and is designed to be as draughty as possible. 17 degrees here is about as comfortable as 5 degrees in the UK, which probably equates to 0C in Canada. It's not like I come into a warm house after a cold motorbike trip. Likewise, a lot of the tips and techniques here WON'T lower the actual temperature of the room but they might make you more comfortable.

High humidity so swamp cooler ineffective, and wind speed required for effective cooling is too high to be feasible. (note – the air movement doesn't really cool the room, but evaporates your sweat faster, making life much more comfortable. I'll come back to this.)

If you have a long hot dry season, then it might be worth investigating a swamp cooler – they use considerably less electricity then normal AC, but the air has to be dry for it to work. I'm right by the sea so humidity never drops below 80%, even when it's 45deg. Even then I know a family that's been using one for years. Can't vouch for efficiency though.

You have two A/C's, both on for 8hrs a day? I assume that's for the night-time then? 17deg is ridiculous. I can think of four possible reasons.
1.It's what you're used to. No sympathy, I adapted, so will you.
2.Your AC is broken or badly inefficient. It might be set to 17 degs, but what's the actual temperature of the air being blown out? Are the coolant pipes well sealed, full and insulated? Where is the compressor blowing the hot air? Are you making the machine work harder then it needs to?
3.Your room is really badly insulated. What is the actual air temp of the room over night? If the walls are hot from the day and radiating heat, the windows leaky and the television and computer both still running, well that's an awful lot of incoming heat for the AC to have to move out of the room. It also means if you turn the AC off, the room temp climbs quickly so you need it running all night.
4.Your bedding – silly question, but are you using a duvet? What's it made of? I grew up in a cold place, I can sleep warm but I need the weight of a duvet to feel comfortable. Because I don't need it to actually keep any heat in I try and use cotton or other breathable things. Towelling works well, and I think denim inside a smooth cotton cover would too.
We use a polyester duvet inside a cotton cover for cooler nights during the winter. We also have a polyester duvet in a polyester cover. Since it traps your sweat it's far too hot and uncomfortable to ever really use, but comes in handy as a second layer during really cool nights (say 17 deg C )

Air movement is a good way to stay comfortable even at warm temperatures – do you have any ceiling fans or pedestal fans? If the temp is about 33deg or lower a good fan blowing on us is normally enough without the AC. A single decent fan is about the same electricity as an old lightbulb (the one next to me now is 65W). I find them especially good if I'm doing something quite immobile (reading, painting, internet, TV ect). You can even take them into the garden when barbecuing.
Often, with the right location of open windows, you can focus the breeze to avoid needing a fan at all. The Aussie government has been putting out some really good guides recently : try here http://www.yourhome.gov.au/technical/fs46.html Most of the diagrams I remember from a guide to designing post disaster tropical housing, but this is a bit more geared to your situation.

As an example of focusing breezes – my house in very long and thin, so we get nice breezes down it from the back windows and door to the fully open front. Between the front and back room there's an interior wall with a door and a large window (to get light into the kitchen). I've put the computer chair just in front of this window, and chosen a chair with an open mesh fabric back (instead of a hot cushioned one). Sitting at the desk, I get a nice breeze on my back most days, enough to keep me comfortable and avoid the use of the fan.
Stuff like this won't solve your major problems, but they are worth checking out to maximise use of what you've already got.

Again, I heartily echo Rabid re exterior louvred shutters. They're also quite reassuring during the storm season. If you can't get permission to fit them then a nice thick dual layered curtain works surprisingly well. It doesn't drastically reduce the total heat coming into the room, but it keeps it near the walls (which are hot anyway) instead of direct sunlight heating the floor or bed ect.

Right, yeah, the walls.
Big old problem here. Soak up heat during the day and output it slowly into your room for the entire 24hr cycle. Great for temperate climates. A pain in the arse in the tropics. God I miss cavity walls.

How big is your apartment block? Because even if you shade or repaint the wall of your apartment, the hot part of the wall above will still conduct heat down to you. Not as much as at present, but far too much to be comfortable. Any solution should really be applied to the entire wall. Since I assume your neighbours are also suffering, you might be able to make a business case to them. Getting the costs accurate will be key there.
Exterior insulation is probably the best option, with reflective paint being the easiest (I think it's an improvement of 3 to 5 deg C normally). Another option is to grow a vine up the wall. You need a storm proof trellis (I'm using cyclone fence hanging off heavy bolts) which is a little away from the wall. I think 5cm is enough but 10cm is recommended. The plant absorbs the heat and shades the area behind it. It also gives off water vapour constantly (evapotranspiration) which can cool the area behind it by up to 10deg C. I like the vines personally because they are cheap, self repairing, UV proof and give fruit. I'm currently trying a rose (not too effective, but security bonus), a Vietnamese climber I don't know the name of (nice, but can turn into a tree so quite a commitment) and passion fruit (dead easy, quite fast growing, can't use anywhere where falling fruit would get stuck in gutters, but on the other hand, FRUIT!). There's also bindweed in the front garden trellis, which is technically a weed but shades the garden nicely until the passionfruit is big enough. To cover an apartment block would take years (maybe 6 months for bindweed), but at reasonably low cost and grapes or fruit are an incentive for the neighbours not to kill it.

If it's any consolation, I have it worse then you. My plot is a long and narrow part of a terrace, with a 2 storey extension out the back. Either side are 1 storey extensions with corrugated steel roofs, radiating heat back up at my walls. Since the house is on the north to south axis, one wall gets blasted all morning, the roof during the siesta hours and the other roof during the afternoon. The walls are solid brick, get up to about 30deg C and conduct this heat throughout the house, even into walls that are shaded. Soon as the aircon goes off or the breeze stops, those upstairs rooms becoming meltingly hot. We just don't use them during the day in the summer, and I'm working on similar ideas to Rabid's suggestions. Since the walls are on the property line, I'm limited on permanent exterior solutions in case the neighbours want to build an extension. I could just knock the walls down and replace them with better insulated ones, but try explaining that to the wife when
she comes back from work to find we've only half a bedroom.

Wall shades and blinds are common here, but the walls aren't easily accessible and I can't see them surviving the storm season – hence the investigations into plants.
At least you don't have to worry about roof insulation, and presumably you've got a nice concrete ground slab for a floor – permanently shaded it'll help keep the house on the cooler side of hot.


If you want it I can give you the build instructions for a solar water heater and basic mini wind turbine, but I think that for money/result ratios, the simpler passive stuff is nearly always better.

[Lord Baal]

Wow! That's a long post! I appreciate your time and effort on trying to help me brother. I will find the answers for you and then post them back here.

Also, I'm on the rabid energy regime now and yesterday I putted up with the heat and tried to use less the ac. Naturally since I got my first fine I have been actively looking to reduce my consume. I had reduce it the past month (compared to last year august) enough to a 100% fine instead of a 200%, so I payed about 60 bucks today instead of 90.

And yeap, they will fine us the next year compared to the current one, so we are pretty fucked up on that side, we must ideally reduce the consume, if we keep it on a range less that 10% then there's no fine, but is we reduce a lot this year next year we are expected to keep reducing or not increase, ever again... until the "crisis is solved", which translates to whenever I give a damn or I'm kicked out of office, whatever happens first.

[madd0ct0r]

just so you know lord ball - my bill for the last month has arrived : 412kwh

are you paying for your neighbours electricity too?

[Lord Baal]

No, but I was for some time believing that a neighbor was hooking up his plugs on my counter, I have checked several times, and actually replaced one of the main wires but it seems it's clean.

I have been following the advices here, my ac is only turned on a few hours if deemed necessary and I set it to 24~25 c° and it fells more efficient! It refresh the room with no trouble and it doesn't keep the compressor on all the time.

I asked around about the insulation be it by panels or a wall of plants, the panels where a immediate not (however they where open to the coating paint as long as it match the building color), some of the neighbors where interested on the plant wall and the prospect of grapes or passion fruit, however a special troublesome one went onto things like birds pooping and watering needed and the leaves making the corridor dirty and whatnot to the point everyone just say we are not doing it, just shut the fuck up.

I'm yet to see this month bill, I hope it gets lower.

[Rabid]

I was also thinking... Depending on the age/quality of your electrical installation, it is possible that one or several of the wires of your installation are badly insulated, and some of the current is lost to the ground. If it is under the sensibility of your Residual Current Breaker (if there is any on your installation), it is possible that you could be losing a non-negligible amount of power this way.

Maybe you could have a look into this ? If you have an electrician friend, this could a good idea to ask him some question about this.


Oh, also : modernizing your electrical installation and putting it up to the current norms of your country is always (in Europe anyway) a good investment. Depending on your locals laws, rules and regulations, this operation could earn you a tax-rebate or some subsidies (In France, it would be a tax-rebate).

[Lord Baal]

That's exactly what a friend told me a while ago. The power comes to my house in two 110V cables, I already replaced one because the original was broken (presumably by chewed by rats while the apartment was unoccupied, I didn't know rats had a taste for cooper). I would be matter of replacing the other one too and see if that lowers the consume, however that amount of cable here doesn't come in cheap and my budget is already very thin as it is, maybe I can convince my sister to buy it if I do the hand work.

[Lord Baal]

Hi! I know this is a really old thread, but somehow I wasn't able to log in again to this forums for a lot of time. Now... on this subject. It turned out I had a pretty fucked up electrical installation. As Rabid suggested, a wire (one of the two main phases, the one I haven't replaced mind you!) was making ground! I paid around 600 bucks (making the conversion to US $) to a guy to bash the part of the reinforced concrete in my floor and replace the wire and other part near the building main fuse, that was somehow fused to the pipe...

On the matter of the excess heat in my bedroom, we recently painted the building and I suggested coating paint for most of the walls most exposed to the sun in apartment building. It's not so wonderful or a magic solution, but the heat was indeed reduced, about 2 or 3 °C, so my AC don't have to work so hard for it.

I would like to thanks everyone here trying to help me!

[madd0ct0r]

cool- my house has been pretty unbearably hot this summer, so I'm glad to hear the paint helped.