Living offgrid with small solar system(s)

[Muhendis]

George.

Why in heavens name would anyone in their right mind use metal for the roof of any building?

According to that web site (plantengine) such materials get torn apart every time there is a thunder storm The only solution according to plantengine, is to pour water over it to keep in cool .

Firstly. A well designed roof of whatever material will have all weather conditions factored into the stress calculations

Secondly. That company is in the business of selling their particular idea so have put a spin on the science for that purpose.

The main items that caught my eye are their claim that the running costs are nearly zero. Also they claim a reduction in AC costs which is only a possibility. There is no guarantee if the savings are worth the installation and costs of maintenance.

Please don't go there...............

[George Harmony]

@muhendis,

More scientific info about roofs in south east asia. Very interesting.

I also was wondering why roofs are not white color.

http://www.sciencedirect.com/science/article/pii/S2095263514000399

@naam,

I thought you were content with metal roof in africa. You designed your current house, so i thought why he did not put metal roof. You still did not give your opinion wether sprinkling metal roof can be effective for heat reduction or cooling.

In my case i would say. Why not give it a try if its easy to realise it and at nearly no cost.

[bankruatsteve]

Well, why don't you give it a try and let us know how it turned out. Why the yada yada?

[George Harmony]

Well, why don't you give it a try and let us know how it turned out. Why the yada yada?

Sure i will. The yada yada is for if someone convinced me its wasting time or it has no effect at all then i wont try it.

[Naam]

@naam,

I thought you were content with metal roof in africa. You designed your current house, so i thought why he did not put metal roof. You still did not give your opinion wether sprinkling metal roof can be effective for heat reduction or cooling.

unfortunately, or rather fortunately, we don't live in a slum where any Bill, Buck, Hank, Joe (or Somchai) can construct a hut and cover it with palm leaves, elephant grass or rusty corrugated metal sheets (neither is zinc aluminium allowed).

the gated community where we built has strict regulations which prevent what i wrote before.

as far as my opinions are concerned i reserve the right to comment or refrain from commenting as i please. the latter applies especially to generalising questions lacking specific facts asked by laymen who are too stubborn to accept advice.

[Naam]

Why in heavens name would anyone in their right mind use metal for the roof of any building?

i had similar thoughts when i first saw the rough construction of the house we lived in (Nigeria). my "why in heaven's name..." concerned a dozen different building specifications. but later it turned out that at least 50% of my criticism was not warranted and that the local architects were familiar with conditions which i never encountered before.

[Muhendis]

Well, why don't you give it a try and let us know how it turned out. Why the yada yada?

I suspect the "yada yada" is seeking reassurance that George is doing the right thing. I also suspect that he already has a pump and is desperate to find a job for it.

[Muhendis]

I notice that a newish steel roofing sheet is starting to appear on new buildings in my area. The top side of the material is as per usual but the underside has a coating of expanded poly something. The coating thickness is about 6mm and folks are saying it makes a noticeable difference.

[KonaRain]

Re: dehumidifier. .

The ones that I've seen for 20 years in Hawaii have a receiver for the water pulled from the air..pour it out once or twice a day..

High wattage though. .Your 50 watts sounds good!

[George Harmony]

unfortunately, or rather fortunately, we don't live in a slum where any Bill, Buck, Hank, Joe (or Somchai) can construct a hut and cover it with palm leaves, elephant grass or rusty corrugated metal sheets (neither is zinc aluminium allowed).

the gated community where we built has strict regulations which prevent what i wrote before

I then prefer to live in a gated SLUM with 24h security where i can decide myself which materials i use for my own house on MY own land on my OWN name

Back to the idea of watering a metal roof. A more crazy idea of mine is to use my roof as a sort of radiator. Pumping around/circulating the filtered cool water from this nearly 1 rai of pond (1m+ deep)next to my house. And all that free during peak hours when its hot including a fan under the roof. Pict speaks for itself.

You can come with your physics calculation of how much water i need and i think i have enough water to pump around :)

Edited May 13, 2016 by George Harmony

[KonaRain]

Even our old address in Hawaii called for no tin roofs..

Nice places demand terrain cotta tile roof..

So I understand. .

(I live in a self built cabin ..

complete fail..)

[KonaRain]

Nice photos!!

[George Harmony]

Even our old address in Hawaii called for no tin roofs..

Nice places demand terrain cotta tile roof..

So I understand. .

(I live in a self built cabin ..

complete fail..)

What do you mean by complete fail???

@naam was very happy with metal roof in africa.

[Gary A]

I talked about metal. But i think mine is zinc aluminium. Like this.

Aircon demand minimum @naam. Why did you not put such a roof in your current house???

I have this roofing material on an addition we put on the back of the house. It looks fine but the stuff is so thin that stepping on it causes damage. The new front porch is normal steel and is much stronger.

[George Harmony]

I talked about metal. But i think mine is zinc aluminium. Like this.

Aircon demand minimum @naam. Why did you not put such a roof in your current house???

I have this roofing material on an addition we put on the back of the house. It looks fine but the stuff is so thin that stepping on it causes damage. The new front porch is normal steel and is much stronger.

Steel roof.jpg

There are here different kind of thickness available, also different types and shapes.

Ive just read this:

George Tsongas, mechanical engineer and professor emeritus from Portland State University, also agrees that an attic fan may not be your best bet.

"Several national studies have shown that radiant heat gain from the roof is a larger contributor to the temperature in the house than is the attic air temperature. While attic ventilation can lower the air temperature in the attic, it doesn't seem to have a significant impact on the temperature in the house."

Attic fans may also present a potential back-drafting risk for in-home combustion appliances, he said.

Tsongas also recommends increasing insulation over adding ventilation.

Putting a sprinkler on the roof on hot days or adding more attic insulation may make more sense for keeping your home cool this summer than spending money on a (solar-powered) attic fan.

.

Hmmm..his name = also george. Perhaps a stubborn scientist.

To be short. Pro and contras. I just give it try with a minimum INVESTMENT. Keep you updated guys after i paint my roof white next month. Perhaps also forbidden in pattaya hahahaha

[Naam]

a quote from the Bible that fits like hand in glove:

Matthew 5:3 "beati pauperes spiritu, quoniam ipsorum est regnum caelorum"

[George Harmony]

Think these people are rich in spirit and full of ideas rather than those poor ups "not last 10hours" minded boosters. GBU.

[George Harmony]

This guy, presumably in chonbury, circulates/sprinkle his roof from a rainbarel which you usually see in Th.

https://m.youtube.com/watch?v=idhhdbGB2s4

[bankruatsteve]

C'mon Naam, tell George that sprinkling his roof is the best thing the physics world has invented so he will quit.

[George Harmony]

Not at all. I think this is a much better invention.

adiabatic cooling:

https://www.tno.nl/en/about-tno/news/2015/8/solar-cooling/

Edited May 13, 2016 by George Harmony

[Muhendis]

George you might benefit from a quick read of this..............

Skanda T Shankarananda, You have only one life, LIVE it!

15k Views

I had the same problem and was trying to find a solution to this few months back. If you are living in the top floor, the best way is to use a heat reflective coating. I live in Bangalore and it gets around 36C during noon and my home used to get too hot. Thermometer in my room used to read 1C-2C higher than outside temperature always. Roof does not cool soon and it stars radiating the heat to lower floors when the outer temperature drops. Due to this, even during night, my room temperature used to be around 30C when it was 25C outside. It was almost impossible to stay inside home during noon even after having good ventilation. One of my friend who is a Civil engineer and is working in a constriction company told me many of the common techniques like lime wash and growing plants are not much effective as they do not cover whole of your roof.

The idea is to cover your roof with something so that it does not absorb any heat at all. He suggested me to use something called as Heat Reflective Coating(Insulative paint) and it worked wonders. It was the cheapest solution I found (Costed me around 4.5k Rs). There are many companies out there who has these products like Fosroc, Pidilite, Monarchindia, etc. I got one from ebay India and applied it on my roof. To my surprise, my home temperature dropped to 29C-30C during noon when it was 36C-37C outside. Fan was more than enough for cooling and this saved me lot of money as I had earlier though of investing in multiple AC's in the house. Before applying the coating, I was able to feel the heat on the roof while walking during evening. After applying it, it is literally cool even during noon. Heat Reflective Coating are mainly used in industries and are not well known or marketed. I fell these can be used for cooling house roofs as well.

Edit: Try not to pour water on the roof for cooling. It does more harm than good. Water gets absorbed by roof and walls and the structures become weak over time. The cooling is temporary and lasts few minuses to an hour and is not effective.

www.quora.com/India-What-are-the-best-ways-to-keep-an-existing-house-cool-in-dry-summers

[George Harmony]

@muhendis,

Thanks for your info. As i said b4 i will sure put a white reflecting coating on my existing roof next month. I can get here as per attached pict.

There are indeed pros and contras for watering (metal)roofs. But this indian guy arguments are not well funded. What does he do again rain then????

Last few minutes?? Also if i sprinkle 3hours??????????

I dont have expectations from evaporation but reduce heat by continiously spraying with cool water only when its very hot outside and ofcourse hot inside.

Edited/added: He said its cheap...hmmmm...he is very lucky then. Its here relatively expensive.

Edited May 13, 2016 by George Harmony

[George Harmony]

@naam asked before, from where do you get cool water if you want to cool using a radiator.

If you do this, will you get cool water?? Instead on your roof for warming up your pool 1m+ under the ground.

[George Harmony]

Well, why don't you give it a try and let us know how it turned out. Why the yada yada?

I suspect the "yada yada" is seeking reassurance that George is doing the right thing. I also suspect that he already has a pump and is desperate to find a job for it.

How about 24hours pumping from the fishpond with no electricity, no solar panel nor battery, no fuel and no human power. 100% free with a ramp pump hahahahahaha

Edited May 16, 2016 by George Harmony

[Crossy]

Well, why don't you give it a try and let us know how it turned out. Why the yada yada?

I suspect the "yada yada" is seeking reassurance that George is doing the right thing. I also suspect that he already has a pump and is desperate to find a job for it.

How about 24hours pumping from the fishpond with no electricity, no solar panel nor battery, no fuel and no human power. 100% free with a ramp pump hahahahahaha

Where does the pressurised water supply that operates the ram pump come from??

[George Harmony]

I thought about it. The pond is at te same level (bit lower) than the groundlevel. Pipe to the top of the pond (just benaeth so underwater). That pipe goes under the ground in my premises about 1 meter. Again just a silly idea of mine. The pump can be much smaller than on the vid. Perhaps it will work. But first i try with a solar powered pump.

About watering metal roof. If you are able to carry heat away faster than it arrives my roof can funtion as a heat exanger since the thermal conductivity is such that watering the top of the zinc aluminium will immediately cool,also underneath the aluminium. Thats my crazy theory. If its in real will work we will find out soon. Lets not forget also that a roof covers the whole area of the house. Now is in physics cold or cool as far as i understand a not existing word but you know what i mean. If you flow ("refresh) continiously ground water on a pan on the stove it will not boil. Or am i talking nonsense here.

Edited May 16, 2016 by George Harmony

[George Harmony]

Talking about pumps. Perhaps sommething for you @gary for your 66rai land if there are water sources every few rai. Two in one. A motorbyke and a pump, complete set available here for about usd 50 only.

https://m.youtube.com/watch?v=igkUJo_lnns

[Naam]

Well, why don't you give it a try and let us know how it turned out. Why the yada yada?

I suspect the "yada yada" is seeking reassurance that George is doing the right thing. I also suspect that he already has a pump and is desperate to find a job for it.

How about 24hours pumping from the fishpond with no electricity, no solar panel nor battery, no fuel and no human power. 100% free with a ramp pump hahahahahaha

Where does the pressurised water supply that operates the ram pump come from??

perhaps lukewarm farts from the Jakarta tooth fairy?

[George Harmony]

Perhaps germans do not know that ram pump also works underwater. More easy to operate.

Edited May 16, 2016 by George Harmony

[Crossy]

George. Where is the energy coming from to pump the water??