Aircon verses Underfloor cooling

[Grubster]

This will not work at all, just forget it completely. First you must understand the "relative part" of relative humidity, then you will understand how none of this is going to work at all. Including post #25.  You will have 100% humidity in your house, your furniture, doors and any other wood products will swell, anything that can rust will rust, not to mention you will be miserably uncomfortable.  This is not for debate. It won't work period, end of story.

[Naam]

2 minutes ago, Grubster said:

 This is not for debate. It won't work period, end of story.

[Naam]

suckers are born every minute.

[Grubster]

21 hours ago, Morakot said:

 

So are you planing to clue the pipes under the ceiling? Placing them deep into a concrete floor/ceiling will surely have no effect. I still don't get the entire set up! What is the inverter or compressor unit? It sound not very effective running (active) coolant though  concrete unless its right at at the surface. Heating pipes are not "buried" in load-bearing structure; they are placed on top of the floor--often on top of thermal insulation--and then covered with a thin layer of screed. If you want to put cooling pipes in the ceiling, there are no off-the-shelf solutions.

 

 

If you are really interested in alternative solutions, looks for natural ventilation in conjunctions with massive grounds slabs that are cleverly shaded . Possibly even a solar chimney and a ground heat exchanger might work, unless you live in a swamp.

 

When this 95 degree and lets say 40% humidity air is cooled to even to 70 degrees it will now be 100% humidity and water will be running back down your pipe while you will be living in 100% humidity, miserable at any temperature. Not to mention that that air would have to move about four feet per hour to cool even close to 70 degrees. 

[steve73]

Typical thai houses built on stilts already benefit from passive underfloor cooling - at least at night.

 

Use of ceiling cooling would result in a novel internal rain - which might be of interest in some specific features, such as internal waterfalls...?

[Grubster]

Ok there is a way to use the ground to cool your house.  You can have a well driller drill a bunch of holes about fifty meters deep and five meters apart from each other. Then you run a half inch copper pipe down and back up each hole. Then connect all these pipes to supply and return pipes above or just below ground and run those pipes to a cooling coil in a fan powered box in your house. This box would need to draw air off the ceiling and then discharge it straight out into the room,  or it could be placed in the attic with supply diffusers and a central return grill mounted in the ceiling, and a condensate drain of course.   That is a very basic system and would probably still require at least one small AC in the house to take the humidity out as there would not be enough temperature drop across that coil to remove enough humidity. The placement of that AC would not matter much as humidity seeks it own level anyway.

         They sell AC units than can be hooked up to your underground piping system through a liquid heat exchanger taking the heat from your condensing unit outside with 60 degree water rather than from 100 degree air pushed over your typical condensing coil. This will cut costs significantly and is used extensively in large buildings that have access to some unused land as they need hundreds of holes. I cannot see how I could get my money back with this system unless I lived a long time. Those units are expensive and probably not available here.  In cold climates they can use this system for both AC and heating with a heat pump unit.

[Grubster]

On 11/24/2016 at 2:26 PM, Crossy said:

 

If you are using the suggested ground-source heat pump you can flip the switch and have toasty warm floors instead :)

 

Very true but it still requires running a compressor, costing money, I piped my concrete slab house in Chicago to a High efficiency gas water heater and it heats the house for about one half the cost of using the High efficiency forced air furnace system that I also have in it for back up as I rent the place out now and it takes days before you will realize the water heater has failed if you don't check it daily, and I don't trust tenants to do his although it is easy to just grab the pipe in the garage when you come or go to see if its warm. I need the furnace to run the AC anyway. Those floors feel great in winter.   I don't see a worthy alternative to the common split system AC's here. Furnaces or other air handlers are way to pricey here.

[windas]

It would appear the main reason for trying to find an alternative to a normal A/con unit is the cost of running/electric consumption.

Until somebody invents a cheaper alternative, why not use SOLAR PANELS to generate the electricity to run the A/con units. Apart from the initial cost, the electicity supply would be free of cost.

[Naam]

2 hours ago, windas said:

It would appear the main reason for trying to find an alternative to a normal A/con unit is the cost of running/electric consumption.

Until somebody invents a cheaper alternative, why not use SOLAR PANELS to generate the electricity to run the A/con units. Apart from the initial cost, the electicity supply would be free of cost.

initial cost still too expensive for aircons. even for other consuming gadgets it takes many years just to break even. but of course it also depends what yield loss you incur by switching financial investment capital to install "solar".

 

[William C F Pierce]

Having lived in the south of Thailand the humidity there is very unbearable I find, but living in the north I found the humidity in Chiang Mai a lot more bearable and less humid. I can therefore understand the complaints of those who live in highly humid parts of Thailand. For an air con to work efficiently doors and windows need to be closed. Using an alternative cooling system can mean you use a certain amount of ventilation. One thing that would come from a ceiling with the cooling is it would be spread over a wider area and would not need to be as intensive as an aircon. It is also not necessary to operate it at the same level as Supermarket coldroom. Like heating systems the  cooling needs to be controlled with a thermostat. One benefit that is lacking in houses in Thailand is very few, if any are built with cavity walls, which can aid both the heating and cooling of a building.  To do my underfloor overlay heating system for 25 square metres in the UK cost me about $1000 DIY.

[Naam]

8 hours ago, William C F Pierce said:

For an air con to work efficiently doors and windows need to be closed. Using an alternative cooling system can mean you use a certain amount of ventilation.

 

some people, e.g. the Mrs. and my [not so] humble self (both used to an airconditioned environment since four decades) have always used "a certain amount of ventilation". in all the homes we built and lived. several small exhaust fans are running 24/7 ensuring a sufficient fresh air supply to provide a comfortable and healthy ambience. needless to mention that this involves more energy consumption which of course means higher cost. in addition to that a whole-house fan is used in the early morning to replace all air volume.

 

the same applies to the mentioned "alternative cooling system" which has unsurmountable disadvantages if the same amount of fresh air enters the home. by the way, cooling systems which do not use forced air blown over evaporators but "falling" air by gravity exist since more than half a century in laboratories. but they are all equipped with drainage pans to get rid of the condensate that is invariably a byproduct of cooling.  

[Morakot]

20 hours ago, Grubster said:

When this 95 degree and lets say 40% humidity air is cooled to even to 70 degrees it will now be 100% humidity and water will be running back down your pipe while you will be living in 100% humidity, miserable at any temperature. Not to mention that that air would have to move about four feet per hour to cool even close to 70 degrees. 

 

I like your cutting edge scientific analysis.

[Morakot]

1 hour ago, Naam said:

several small exhaust fans are running 24/7 ensuring a sufficient fresh air supply to provide a comfortable and healthy ambience. needless to mention that this involves more energy consumption which of course means higher cost.

 

Yes, especially when the fan is placed directly next to the A/C, as cowboy building code (CBC^TM)  seems to dictate.

 

[Naam]

2 hours ago, Morakot said:

as cowboy building code (CBC^TM)

[Artisi]

On Wednesday, December 07, 2016 at 8:28 AM, Naam said:

you don't seem to have the faintest idea what volume of condensate is drawn out of the air and drained by a single aircon unit when the ambient relative humidity is ~80%.

 

On Wednesday, December 07, 2016 at 8:28 AM, Naam said:

you don't seem to have the faintest idea what volume of condensate is drawn out of the air and drained by a single aircon unit when the ambient relative humidity is ~80%.

Like a constant (badly) leaking tap.

[Strange]

Just now, Artisi said:

On 12/7/2016 at 8:28 AM, Naam said:

you don't seem to have the faintest idea what volume of condensate is drawn out of the air and drained by a single aircon unit when the ambient relative humidity is ~80%.

 

On 12/7/2016 at 8:28 AM, Naam said:

you don't seem to have the faintest idea what volume of condensate is drawn out of the air and drained by a single aircon unit when the ambient relative humidity is ~80%.

Like a constant (badly) leaking tap.

 

Its mind boggling how people underestimate the volume of water pulled out of the air in a Tropical climate like Thailand, or my home state of Florida (Wink Wink Naam) through the cooling process of ambient air passing over an evaporator, removing heat and collecting moisture. 

 

I have one of those outside clay pot things about 2 ft high and 3 ft wide. 1 18K BTU Aircon will fill it up in 24 hours when its warm outside. Thats probably 4 gallons of water. Pulled out of the air. Cooling my living room. 

 

Another way to think about it is the "Beer Can Effect" and how water condensates on the can immediately after you pull it from the fridge. 

 

Think about if your floor was 50 degrees F and what that would look like with Thailand's ambient temps & humidity. 

 

There is just no way, in reality, that you can cool a house with a refrigerated floor. 

[Strange]

On 12/8/2016 at 6:50 AM, jacko45k said:

You make a good point for most areas of Thailand where the heat is usually accompanied with high humidity. An underfloor system would not remove the humidity. It may even produce a wet slippery floor, or water dripping from the ceiling, and cause mold.

 

Its not "may even produce" its "will 100% produce" a soaking wet floor, mold, disease, bacteria, etc. 

[William C F Pierce]

On 07/12/2016 at 3:38 AM, catinthehat said:

Anyone here ever seen an "underfloor heating system"? Didn't think so. there are other issues with this.

• The cost of all of the extra kit would be a deal breaker
• With all of that added duct work it wold be a magnet for bacteria and mold (i.e. Legionnaires disease) And would result in the need for major duct cleaning and disinfecting on a regular basis. More cost.
• We use numerous pedestal fans which are much cheaper to run than  air-cons.
• Add to that the above noted moisture issues.

My own underfloor heating system I installed in the UK consists of overlay boards 600 x 900 x 18 mm with 4 flow and return grooves to take 12 mm pipework in one continuous zig-zag length.  This was then overlaid with tiles. As a cooling system it can take a hardwood overlay in a bedroom as it has a different ambient temperature and not too cold for the feet. If you don't like the running costs of an aircon, it is a possible alternative which I intend to try on having in a new build.

 

Underfloor cooling is gradually coming into use in southern Europe. This is still in the early stage of development and would in time find a suitable version arriving in Thailand. CONDENSATION: The low running cost of a small 6" extractor fan that comes on automatically at a certain humidity level is a viable option. The condensation is greater or less depending on the balance of materials used. Just as you would not have uncontrolled heat in a home. Likewise you would not have uncontrolled cooling  within a given design. If there is a problem look for a solution.

[William C F Pierce]

On 08/12/2016 at 2:51 PM, Naam said:

initial cost still too expensive for aircons. even for other consuming gadgets it takes many years just to break even. but of course it also depends what yield loss you incur by switching financial investment capital to install "solar".

 

A home is not a business. You do not equate a profit from everything you ever purchase for a home or it's running costs. Some people do have to consider the running costs of affordability, whilst others do not.

[Strange]

23 minutes ago, William C F Pierce said:

A home is not a business. You do not equate a profit from everything you ever purchase for a home or it's running costs. Some people do have to consider the running costs of affordability, whilst others do not.

 

In other words, the technology just does not exist in regards to air-conditioning a home with solar power. Its not there yet in a household form. The outlay and surface area required to cool a home in tropical climates like Thailand, as well as run all the consumer items in the home, is just not cost effective. Its cheaper to pay your electric bill. 

[Strange]

49 minutes ago, William C F Pierce said:

Underfloor cooling is gradually coming into use in southern Europe.

 

Do you have a youtube vid handy to show what you are talking about? Just a general principal vid. 

 

Im genuinely curious because I don't see how it will work. There are several schools of thought on how to cool a home via 'underfloor' or 'underground' cooling. None of witch are a viable option compared to just bolting in an air conditioner and pressing "on". 

 

Can you drop an informational link to what you are looking at? 

[LindsayB]

heres a short you tube vid

 

 

[LindsayB]

and another with a actual install and explaining the use of a much smaller aircon to remove the moisture

 

 

[Naam]

only absolute ignorants would use the expression "radiant" in context with "cooling"

[LindsayB]

http://energy.gov/energysaver/radiant-cooling

[Naam]

Quote

radiate

verb

verb: radiate; 3rd person present: radiates; past tense: radiated; past participle: radiated; gerund or present participle: radiating

ˈreɪdɪeɪt/

1. 1.

   emit (energy, especially light or heat) in the form of rays or waves.

 

absorbing heat energy cannot be called radia*.*! case closed, ignorants still allowed to use radiant, radiate, etc.

[bankruatsteve]

Assume the heat is being absorbed somewhere else (IE: not at the cooling coils).  How about conductive?

 

Oops that doesn't make sense.  Anyway... conductive?

 

[LindsayB]

Radiative cooling on Earth's surface at night

Radiative cooling is commonly experienced on cloudless nights, when heat is radiated into space from the surface of the Earth, or from the skin of a human observer. The effect is well-known among amateur astronomers, and can personally be felt on the skin of an observer on a cloudless night. To feel the effect, one compares the difference between looking straight up into a cloudless night sky for several seconds, to that of placing a sheet of paper between one's face and the sky. Since outer space radiates at about a temperature of 3 kelvins (-270 degrees Celsius or -450 degrees Fahrenheit), and the sheet of paper radiates at about 300 kelvins (room temperature), the sheet of paper radiates more heat to one's face than does the darkened cosmos. The effect is blunted by Earth's surrounding atmosphere, and particularly the water vapor it contains, so the apparent temperature of the sky is far warmer than outer space. Note that it is not correct to say that the sheet "blocks the cold" of the night sky; instead, the sheet is radiating heat to your face, just like a camp fire warms your face; the only difference is that a campfire is several hundred degrees warmer than a sheet of paper, just like a sheet of paper (at approximately air temperature) is warmer than the deep night sky.

The same radiative cooling mechanism can sometimes cause frost or black ice to form on surfaces exposed to the clear night sky, even when the ambient temperature does not fall below freezing.

[Strange]

1 hour ago, LindsayB said:

heres a short you tube vid

 

The last words in that video are "Perfect match for geo-thermal cooling"

 

1 hour ago, LindsayB said:

and another with a actual install and explaining the use of a much smaller aircon to remove the moisture

 

The floor temp in that vid was 24 celsius. 

 

Even in the hottest days in thailand, I doubt our floors are getting anything higher than 24-25 celsius without underfloor cooling. Why do you think Thais are always laying about on the tile floors? Geo-thermal temps and the cement slab cap the earth and retain its geo thermal temps, witch are cooler than the ambient air outside. 

[Naam]

5 hours ago, Strange said:

The floor temp in that vid was 24 celsius. 

i'm not sure what the floor temperature but the location is Delhi, id est june, July, August and September monsoon with 95% relative humidity. then there was a chiller, (no capacity given!). same same for the (quote "much smaller airconS" [plural] to remove humidity). Delhi area in April/May and October very dry (30-35% r.H.) = no need for any dehumidification.

 

my last comment on floor radiant cooling: "snake oil sellers!" and now i will radiate during my afternoon nap