Geothermal Passive Cool Air

[ArranP]

Got some temperature readings taken today at 3pm.

31.0*C / 87.8*F ambient air temp (taken from thermometer fixed on shaded balcony)
29.5*C / 85.1*F water temperature from pool exposed to direct sunlight
26.5*C / 79.7*F water temperature from concrete water tank under house ( few thousand litres )

any suggestions ?

My thoughts : run x number of metres of air pipe coiled around the base of the concrete tank under the house. The pipe inlet to take in ambient air, the pipe outlet to be several vents several at the floor of the house.

http://en.wikipedia.org/wiki/Windcatcher


Upward aIr suction to be supplied via solar chimney.

http://en.wikipedia.org/wiki/Solar_chimney

[DtemJai]

Non practical – earth temp a 20 cm down are constants @ 28 degree, heat always travel upwards…so use preventive heat build up on lower level…2 months more and return of 38 for those are unprepared.

[splitlid]

wind towers are used in hot, dry arid climates (hence the qanat reference in the dwg) and are not suited for humid climates.

[ArranP]

wind towers are used in hot, dry arid climates (hence the qanat reference in the dwg) and are not suited for humid climates.

one interesting thing I have found since I bought my thermometer that gives humdity.

During the day when it is hot 33*C humidity is 59%, in the mornings when it is cooler 25*C humidity is 84%

[DtemJai]

1. http://www.tmd.go.th/en/province.php?id=23

[bankruatsteve]

I like "green" for just about everything that makes sense. But passive cooling/heating takes ideal circumstances to be anywhere near effective and almost always ends up with fans and other add-ins that try to make it better but just don't. In a humid/tropical climate there comes the time when you really need the A/C and nothing else will help.

[ArranP]

I like "green" for just about everything that makes sense. But passive cooling/heating takes ideal circumstances to be anywhere near effective and almost always ends up with fans and other add-ins that try to make it better but just don't. In a humid/tropical climate there comes the time when you really need the A/C and nothing else will help.

yep, I think I'm reclined to accept

i) roof with good solar reflectance and foam insulation

ii) double walls with cavity

iii) open doors and windows in the day for cross ventilation

iv) a few fans

The house I'm renting has single course on the west wall which is my bedroom, its too hot in their when I go to bed, I have to use the air con to cool it down.

I don't mind 30*C or 31*C in the the house, so long as the walls are not holding the heat and there is a breeze.

The house I am building has sea view, facing south, full height window openings on both north and south sides, winds comes from the east to south-west depending on the season.

The only time I use air-con is in my bedroom in the rented house is in the evening, So in my new house I think I may not need to use air-con as the walls will be double course with cavity and roof will have a solar reflectance of 92% (white colorbond metal klip-lok ) with foam insulation.

The only other passive solar option that would work here in the tropics, is the solar chimney on windless days.

[T_Dog]

We considered the solar chimney concept when we were building a house, but mold mitigation in the earth tubes would be a tough obstacle in humid Thailand. Successful implementations have only occurred in hot and dry countries from what I could determine.

[ArranP]

We considered the solar chimney concept when we were building a house, but mold mitigation in the earth tubes would be a tough obstacle in humid Thailand. Successful implementations have only occurred in hot and dry countries from what I could determine.

A user on one of these forums had succeeded, they used high / low ridged plastic tubing, cut saw lines through the high ridges on the underside of the tubes to let the condensation moisture escape to the earth, and wrapped the tube in some sort of membrane.

however the difficulty here in thailand is getting a sufficient delta in temperature, the ground is usuall only 2*C below the ambient. hence why I looked at the an underground water tank, but how do you get the condensation/moisture to escape from these, cannot use the same method as the earth pipe above as the pipes are emersed in water.

Edited January 30, 2015 by ArranP

[IMHO]

I like "green" for just about everything that makes sense. But passive cooling/heating takes ideal circumstances to be anywhere near effective and almost always ends up with fans and other add-ins that try to make it better but just don't. In a humid/tropical climate there comes the time when you really need the A/C and nothing else will help.

yep, I think I'm reclined to accept

i) roof with good solar reflectance and foam insulation

ii) double walls with cavity

iii) open doors and windows in the day for cross ventilation

iv) a few fans

The house I'm renting has single course on the west wall which is my bedroom, its too hot in their when I go to bed, I have to use the air con to cool it down.

I don't mind 30*C or 31*C in the the house, so long as the walls are not holding the heat and there is a breeze.

The house I am building has sea view, facing south, full height window openings on both north and south sides, winds comes from the east to south-west depending on the season.

The only time I use air-con is in my bedroom in the rented house is in the evening, So in my new house I think I may not need to use air-con as the walls will be double course with cavity and roof will have a solar reflectance of 92% (white colorbond metal klip-lok ) with foam insulation.

The only other passive solar option that would work here in the tropics, is the solar chimney on windless days.

Ref the full height windows to the south... Have you considered using Solartag glass on them?

[ArranP]

i will look into that, in some places windows with a good solar reflectance will be needed or shade from balcony trelace / pergola