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How feasible would it me to design a heat exchange system to cool houses in the tropics?Quote:
Originally Posted by watterinja
We have these systems for heating houses in the UK, but they can also be used to cool. The only problem is that the UK systems use a fairly specialist manifold system, which I think would be too complicated and too expensive for this part of the world. Simplify this and I think you could have a winner.
If it's ok with you, I'll set up a separate heat-pump thread & we can explore the ways the technology can be used.Quote:
Originally Posted by Marmite the Dog
A byproduct of a air-to-water heat-pump, is that while the water is being heated, the byproduct is cold air which can actually be used to cool a house. In Asia, this is a neat trick, that means you can both heat water for say hotels, homes, as well as providing some cooling load.
My mate and I were discussing this topic just last week.Quote:
Originally Posted by Marmite the Dog
All you need is a;
1. A water tower, a water tank or better still a swimming pool.
2. 2 second hand car radiators.
3. A large fan.
4. Some insulated pipe.
5. And a small electric water pump.
Don't want to give too much away but we are confident we can achieve an air temperature of 22 degrees celcius and that is cool enough for me! :)
^
Please tell me more
I got everything except #2 & #4
I'm listening :)
I will keep you posted Thety!
We envisage massive savings with regard to installation costs not to mention electrical energy savings.
Remove all electric wiring from you aircon's outdoor unit.Quote:
Originally Posted by Thetyim
Put the unit in your hot water tank. :)
Be interested to see what your calculated heat-load requirements are. You may find some surprises. Cooling air in a space requires a fair bit of heat-transfer. The air often feels cold on touching the skin, but is not enough to overcome the various room heat-losses & pull-down requirement. :)Quote:
Originally Posted by Loy Toy
Watch also things like humidity, post cooling & condensation inside the house. :)
Sounds like what I had in the US many years ago. Called it a swamp cooler.Quote:
Originally Posted by Loy Toy
https://teakdoor.com/images/imported/2009/04/466.jpg
^^ All of those dynamic reactions have to the considered mate and I am sure the prototype instalation will be modified and according to the results. Bit of fun really and between 2 common sense driven novices.:)
I will keep you posted also and I appreciate your advice! :)
^^ Pretty much as we see it but pumping the cool air through floor vents and possibly have cooling pipes in the wall cavities.
We will try various arrangements and piping configurations but firstly will spend our time determining what air temperature consistancy we can achieve and also considering condensation levels.
^^ When you're ready, please advise on your COP.
Have no advice. I know naught about the thermal characteristics and the like. I do know they are cheaper than air con on energy use but air con does a better job of cooling.Quote:
Originally Posted by Loy Toy
I have also used this type of device in the Arizona and California deserts... The key to optimum usability is a very low ambient humidity something not readily found here in the southern reaches. Might work in the hottest areas of dry Issan though.Quote:
Originally Posted by Norton
Spectacular results were achieved in Arizona even in midday 104 deg. F.
E. G.
That's why I asked for the COP of the system.Quote:
Originally Posted by Norton
It could turn out - horror - to be far worse than an aircon system. :)
As I remember, swamp coolers work well in dry climate 30% humidity range. I had one when I lived in the Mojave Desert and it did cool the house. In high humidity like Thailand I don't think they are very efficient.
I was thinking along the lines of a geo-thermal system, as I'm not a fan of Legionnaire's Disease. :)
.........:)Quote:
Originally Posted by El Gibbon
Holy crap. Drill a hole in the ground. A deep one here in Thailand. When you get steam coming out use it to drive a generator hooked up to an air con. All free and works good. That hole might be a tad expensive though.;)Quote:
Originally Posted by Marmite the Dog
A very, very valid point.Quote:
Originally Posted by Marmite the Dog
What are your thoughts on a geo-thermal system?
Umm, you don't need to hit a volcanic spring to get it to work, mate. :)Quote:
Originally Posted by Norton
If they could be made efficient, then I think they could be very viable.Quote:
Originally Posted by watterinja
Usually in the UK they dig trenches all over the place and lay the pipes in there. I saw one design where they used post footings for the house's construction, so they put the pipes in the steelwork, put that down the bore-hole and them poured the concrete posts as normal. This was done on a site that didn't have a large garden, but did have lots of posts.
In Thailand, the post holes are not usually that deep, so a change would have to be made there, as you'd probably need over 2 metres in depth depending upon the efficiency and number of posts, as well as the size of the area that needs to be cooled.
There are a few companies in Thailand providing ventilation cooling system for factory halls, mostly they can achieve 5 degree Celsius below room/hall temperature...
A big vent thing ranges from 6 to 20 k thb for some industrial use...
Higher humidity in air, less efficiency ! Those kind of things are called desert coolers as well, as picture shown few thread up, in India, it works well in Dehli but not good in Bombay due to humidity !
Should find some links by digging my fair visit files...
The heat exchange with a deep hole is another story, used a lot in Switzerland, to cool or to warm up, mainly factories, prolly to expensive investment for a house as per today...
There is a fair regarding this topic in october :
Event Name : The 7th - Bangkok Refrigeration, Heating, Ventilation, and Air-Conditioning 2009
(Bangkok RHVAC 2009) https://teakdoor.com/images/smilies1/You_Rock_Emoticon.gif Date : 7 - 11 October 2009
Trade days : 7 - 9 October 2009 (10.00 – 18.00 hrs.)
Public days : 10 - 11 October 2009 (10.00 - 18.00 hrs.) https://teakdoor.com/images/smilies1/You_Rock_Emoticon.gif Venue : IMPACT ARENA, EXHIBITION AND CONVENTION CENTER MUANG THONG THANI
99 Popular Road, Banmai Subdistrict, Pakkred District, Nonthaburi 11120 Thailand https://teakdoor.com/images/smilies1/You_Rock_Emoticon.gif Organizer : Department of Export Promotion, Ministry of Commerce, Royal Thai Government Office of
Trade Fair Activities
22/77 Rachadapisek Road, Chatuchak, Bangkok 10900 Thailand
Tel : (66) 2 513 1909 to 15 ext. 299, 272 and 293
Fax : (66) 2 513 1565, 2 512 2234
Website : Fair Information : Bangkok Refrigeration, Heating, Ventilation and Air-Conditioning 2009 , www.thaitradefair.com
E-mail : rhvac[at]depthai.go.th https://teakdoor.com/images/smilies1/You_Rock_Emoticon.gif Co-Organized by : >> Air Conditioning and Refrigeration Industry Club, The Federation of Thai Industries https://teakdoor.com/images/smilies1/You_Rock_Emoticon.gif Supporters by : >> Thai Refrigeration Association >> Air Conditioning Engineering Association of Thailand >> Thai Industrial Standards Institute, Ministry of Industry >> Department of Industrial Promotion, Ministry of Industry >> Electricity Generating Authority of Thailand >> ASHRAE Thailand Chapter https://teakdoor.com/images/smilies1/You_Rock_Emoticon.gif List of Exhibits : >> Air- Conditioning >> Refrigeration >> Heating >> Ventilation >> Part, Material and Service >> Tools & Equipment >> Others https://teakdoor.com/images/smilies1/You_Rock_Emoticon.gif Number of exhibitors : Approximately 180 companies/ 525 booths from both domestics and overseas https://teakdoor.com/images/smilies1/You_Rock_Emoticon.gif Visitor profile : Trade days : Buyers, importers, manufacturers, traders, distributors, wholesalers,
retailers,department stores, etc.
Public days : Trade visitors, local consumers and foreign tourists are expected. https://teakdoor.com/images/smilies1/You_Rock_Emoticon.gif FIGURE DATA 2007 2009 (Expected) 1. Number of exhibitors 172 companies / 516 booths 180 companies / 525 booths 2. Participating countries Thailand, Malaysia, Singapore, India, Taiwan, USA, Italy, China Thailand, South East Asia, Middle East, India, Europe, USA 3. Exhibition area 9,500 Sq.m. 10,000 Sq.m. 4. Number of visitors
https://teakdoor.com/images/smilies1/You_Rock_Emoticon.gif Trade days https://teakdoor.com/images/smilies1/You_Rock_Emoticon.gif Public days
6,200 8,836
7,500 12,000 5. Major visiting countries Malaysia, India, Singapore, China, Vietnam, Korea, Philippin, Iran and Indonesia ASIAN, South is Asia, Middle East, China, South America, Latin America and Europe
The problem with wanting to cool is that the cooling in a conventional aircon system is on the evaporator end (inside). The condenser (outside) end essentially passes the (room heat)+(compressor heat)=(condenser heat) into the surrounding air. In other words, moving low-grade thermal energy - room air - to high-grade thermal energy & dumps it.Quote:
Originally Posted by Marmite the Dog
Now, in this scenario, you would need to dump the condenser heat into the geo-thermal system at rather a large temperature - probably at entry, at anything around 60-100'C (depending on compressor load), dropping off to a saturation temp of anything between say 40-65'C.
Chances are that this heat could present some problems in the ground loop - not sure - haven't though it through carefully. It's doable - but, has to be designed properly. May be expensive.
For an air-to-water heat pump, we use this condenser load to raise the temperature of water to anywhere as high as 65'C (HFC's), or even 80'C (CO2).
https://teakdoor.com/images/smilies1/You_Rock_Emoticon.gif
A heat-pump on test in my lab, in Laos. The AWHP is the white box on the top of the stand.
^ The energy consumption of an air-to-water heat-pump is around 14-20% of what a direct resistive element heater will consume (measured in the lab).
At the same time, the cold air can be used to cool the house.
By-the-way, the AWHP shown above will, serve the daily needs of a 20-room hotel, or guest-house.
The hot rocks project worked in Cornwall
However the cost of drilling an fuel you amy as well use iced champagne for cooling
The Arizona system is also unsuitable here.
Passive design, roof extraction and alignment etc are more cost effective ,I also swear by Hebel block .
The subtle use of screens light shelf and plants can all assist.
I designed my own home here usung 20cm thickness like a Thai temple.
The Uni of Queensland and Oz in general has a lot of good info and experience.PM if you wish advice on anew design or retro fit.