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4MyEgo

Reducing The Heat In The House

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I've just come home to the Isaan house after 3 weeks away.

1. The Isaan house has monier red cement tiles, double sided insulation under them, with a 2 " gap between tiles and insulation.

A very small ceiling roof space.

High cathedral type exposed beams internal build with red brick cavity walls and expensive paint job.

2. The shed has 10 cm Qcon blocks with red type colourbond (insulation underneath) as part of the roof sandwich.

There is an free flow air space under the roof.

So returning to the abode and getting out of the car in the garage, it was warm.

Now, entering the house, locked up for 3 weeks, it was lovely and cool.

Without scientific knowledge, the cement tiled, red bricked, small ceiling house is cooler than the metal/insulation sandwiched roof and Qcon brick construction.



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5 hours ago, selftaopath said:

Thanks for your post. Do you know where thermostatic vent fans can be gotten in Khonkaen? I think I'd opt for one or two. I have difficulty finding modern items. In US I had a "whole house" fan. It really did a nice job of bring air into the house... but not desirable if the air is HOT. Could bring a breeze however.

 

OK I sold the house that had the fans, but Ill try and link you to the basic system I made. I couldn't find a kit so made one. 

 

I bought 4 of the biggest CFM fans I could find, that were moderately quiet (no calculation or science, anything is an improvement). I bought 4, kept 2 for spare parts. Took them apart and made a fixture to mount them in the ridge vent on the inside so they couldn't be seen and in an orientation to pull air out of the attic. 

 

Bought a temp controller like this, shows current temp where the probes are, cut in and cut out set-points. 

 

http://www.lazada.co.th/220v12v-digital-led-temperature-controller-10a-thermostat-controlswitchprobe-12v-8816815.html

 

29401e43-7f83-f354-5613-16f0981dbbe8.jpg

38d8d1b6-62d1-617b-f0d3-d2daf41d513d.jpg

 

With a longer probe (I think I bought like 6m probes) 

 

http://www.lazada.co.th/thermistor-accuracy-temperature-sensor-10k-3435-waterproof-probe-4m-9008087.html

 

e81dc2b4-9411-39e0-5b9f-835572ae2130.jpg

 

And wired it up so that the controller switches the fans directly. I cut the plugs off and wired direct, but you can install outlets and switch the outlet. Gotta do a little checking about the amperage draw of the fans and the rated capacity of the switch though. 

 

Cut a hole in front of a metal switch box and mounted the controller on it. Ran the probe through conduit into the attic space and wiring for the fans back to the switch box. Mounted the switch box next to the breaker panel on the wall to get power from and its convenient as the breaker panel was central in the home. Switch Box was kinda like the one below. 

 

 sheet-metal-junction-box-250x250.jpeg

 

I only had like 4-5K baht into it. Its not hard or complicated, just have to do a little figuring. The thais building the house and helping me could not figure out what I was doing and thought I was crazy. Worked good though. 

 

Edit:

 

I also had electronic controllers for watering the grass outside automatically and on a timer mounted in/on the metal switch box as well. For convenience so I could just change the times they came on and the length of time they stayed on, from inside the house. So it was a multifaceted deal and worked out pretty good and serviceable. 

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On 10/13/2016 at 1:01 PM, Naam said:

the air volume of a stilted area is not miraculously converted into a measurable "thermal mass" when enclosed.

 

air is a low density gas and has the least capacity of absorbing and storing heat and the least resistance to change of temperatures (thermal physics 101 which i studied half a century ago).

A diagram shows two houses; one on a concrete slab on the ground, the other on stilts. If the outside temperature is 35 degrees Celsius, and the ground temperature is 22 degrees Celsius, and the inside temperature is 25 degrees Celsius, 600 watts of energy will be transferred from inside the home to the thermal mass of the house. For the house on stilts, these same temperatures outside, beneath and inside the home would mean that 2000 watts of energy will be transferred from beneath the home into the house, via air flow from the vented floors.   A diagram shows two houses; one on stilts with an open subfloor, the other also elevated but with an enclosed sub-floor. Both houses are depicted with an outside air temperature of 35 degrees Celsius, a ground temperature of 22 degrees Celsius and an inside temperature of 25 degrees Celsius. For the house with an open subfloor, the temperature in the open subfloor area is the same as the outside temperature, i.e. 35 degrees Celsius, which means that 2000 watts of energy will be transferred from beneath the home into the house via air flow from the vented floor. For the house with an enclosed subfloor, the enclosed sub-floor air temperature is 28 degrees Celsius, meaning that only 600 watts of energy will be transferred from this space into the house and the ground below.

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I am a mechanical engineer that majored in heat transfer a long time ago.  My co worker here in sunny San Diego bought a fairly large house and he is a PhD in a different field.  He has a long porch/veranda with windows along the sunny side of his  house that of course had a lot of sun load.  Most people of course will close the shades or blinds.  He installed remote control operated shades on the Outside of the house windows!  Point and click and they go up and down on their rollers.  Since they are under the porch roof/eave, there is no real weather or rain issue.  The shades on the outside work as a sun shield umbrella.  Frankly, If I had the time or energy I would come up with some thing similar to that that would go on a house roof and that would act like an umbrella.  People would be surprised how effective a sun shade/umbrella would be.

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PD-PC-ThermalFloors1and2_fmt.png   PD-PC-ThermalFloors3and4_fmt.png

I love the pics, can you learn me about the red arrows and the numbers and W symbol.

Remember I was only a teacher, and, though we think so, we don't know everything. [emoji6]

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8 minutes ago, carlyai said:


I love the pics, can you learn me about the red arrows and the numbers and W symbol.

Remember I was only a teacher, and, though we think so, we don't know everything. emoji6.png

Sent from my SM-J700F using Tapatalk
 

Watt of energy going in direction of the arrow I think.

But I have been wrong before.

And here in Thailand you can't be 100% sure of anything 55555

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22 minutes ago, gk10002000 said:

Frankly, If I had the time or energy I would come up with some thing similar to that that would go on a house roof and that would act like an umbrella. 

 

I mean energy wise I'm lazy as shit lol. I just make stuff up and hire guys to climb around installing it with my supervision. Cheap labor is great. 

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Just now, bokningar said:

Watt of energy going in direction of the arrow I think.

But I have been wrong before.

And here in Thailand you can't be 100% sure of anything 55555

 

So you are not sure of what you posted?

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15 minutes ago, carlyai said:


I love the pics, can you learn me about the red arrows and the numbers and W symbol.

Remember I was only a teacher, and, though we think so, we don't know everything. emoji6.png

Sent from my SM-J700F using Tapatalk
 

The arrows show the direction of heat or energy flow.  A key thing is how the stilted house, that many people do with open air flow really is not that good once the outside air warms up.  The enclosed air flow stilt floor keeps the hot outside air from circulating under the house.

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1 minute ago, gk10002000 said:

The arrows show the direction of heat or energy flow.  A key thing is how the stilted house, that many people do with open air flow really is not that good once the outside air warms up.  The enclosed air flow stilt floor keeps the hot outside air from circulating under the house.

 

So he unintentionally confirmed Naam's post.

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Watt of energy going in direction of the arrow I think.

But I have been wrong before.

And here in Thailand you can't be 100% sure of anything 55555

Ahhhhh, I thought that, but come on....you can't write degree numbers (which I did understand), then draw red arrows, then write numbers in Watts and expect me to understand it. Those wattage numbers need more explanation. Without the Falang writing, those pics look like street signs at the top of the Pattaya look out, and there, no one knows which way to go.[emoji21]

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Ahhhhh, I thought that, but come on....you can't write degree numbers (which I did understand), then draw red arrows, then write numbers in Watts and expect me to understand it. Those wattage numbers need more explanation. Without the Falang writing, those pics look like street signs at the top of the Pattaya look out, and there, no one knows which way to go.[emoji21]
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Let me have another go: so if there is about a 10 degree difference in temperature, you're pumping about 1Kw of energy into the house, making the house hotter.

Where as with the slab as part of the ground, you're taking 600 W of energy out of the house therefore making it cooler.

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14 minutes ago, carlyai said:


Let me have another go: so if there is about a 10 degree difference in temperature, you're pumping about 1Kw of energy into the house, making the house hotter.

Where as with the slab as part of the ground, you're taking 600 W of energy out of the house therefore making it cooler.

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ladies and gentlemen... WE HAVE A WINNER! :smile:

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38 minutes ago, bokningar said:

Watt of energy going in direction of the arrow I think.

But I have been wrong before.

And here in Thailand you can't be 100% sure of anything 55555

you are not wrong! of course the heat transfer depends on the house' exposed "bottom" surface area. could be a multiple of 600W (down or up) with big homes.

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ladies and gentlemen... WE HAVE A WINNER! [emoji2]

Red wine all round....where I live....that means meeeee....weeeee.

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