and planting fruit trees, vegetables and flowering plants. I added ceiling fans to the dwelling and opeened both windows and screens to maximize qairflow across the 9 feet wide shaded porch and through the house. I added bamboo screens to the porch to further shut out the hot rays of the evening sun. I even sat in front of a fan wrapped in a wet towel to try to cool off by evaporative cooling. I was able to do without air conditi9ning but it sure was difficult and not comfortable. I finally starting using the air conditioner during midday and in the hot evenings as a last resort. So I know first hand that even after you make a lot of effort it is still awfully hot in Bangkok requiring air conditioning in the hotter months of the year. I believe we could really contribute to energy efficiency, reduction of Bankok's heat island effect, family household money saving, reduction of pollution and Bangkok's contribution to global warming.
We could do this by using two innovations, one from the USA and one already tested successfully in Thailand. The first is the use of cool colored roof coatings such as are available from Bayer AG to reflect 30% or more of the heat from Thai concrete tile roofs and walls or purchase tiles which do the same. In this waty current and future dwellings cut their contribution to global warming and energy use. Second a field studt done in Bangkok shows that a condenser coil buried one meter underground can save half of the energy needed for air conditioning, Until we start using commonsense measures like these Bangkok will get hotter and hotter and famiies will continue to pay more than is necessary to ensure comfort.
You second suggestion about putting the condenser one meter below the ground level (in shade) may not save any energy.
As the solar gain by the earth during the day heats up the top layer of the earth to a higher temperature than the ambient.
Minimum depth required for using the earth as a heat sink will have to be at least 2 to 3 meters and you can save about 20 % energy at best .
Of course ,there are other issues such as additional cost ,refrigerant leakage and corrosion of the metals etc.
This is where I got my information , where did you get yours? where did you come up with 2 to 3 meters down to bury the condenser? In Bangkok in many places you would be in very wet soil and after you hit the highly conductive heat wicking wet soil what would you gain by going deeper? Where does the efficiency gain of 20 % come from? I welcome such discussions but everyone needs to know where we get our information. You may be right in what you say and I certainly welcome that you want to improve things in Thailand, but we need to further investigate our disagreement on the impact of a buried condenser. If the field study is inaccurate we should not rely on it and if it is accurate we should use it fully to combat global warming, heat island effects in Bangkok, and just improve energy efficiency. Best wishes Randy
As far as using the heat from bus engines to run a desiccant cooler I think I saw somewhere where someone was using engine head to run an absorption cooler for cars.
Air conditioner COPs vary from a low of about 1.7 to a high of about 3.3 for domestic air conditioners. I am unable to understand the statement “The study also stated the coefficients of performance increased respectively to 7.1 and 8.1”
I wish I could lay my hands on the study .If you have a copy could you please PM it. I tried to meet Joseph Khedari but understand he has moved to another job.
I have been practicing passive and Low energy cooling techniques for buildings for more than a decade. My reference was a project I did with well known Indian architect in India for air cooling a school auditorium with an Earth Air Tunnel. We monitored temperatures at 1 to 3 meters depth with 0.5 Meter intervals. Our records indicated temperature variations from 30oC at 1 meter depth and 25o deg C at 3 meters depth respectively at an ambient temperature of 40o C. Test was conducted in the monsoon season in New Delhi. Similar work has been done by some other group in India under a grant from Gujarat Energy development Agency. There report is available at http://www.builditsolar.com/Projects/Cooling/Earth%20Tubes2003-01-07GirjaSharan.pdf
Based on the proximity to sea and soil conditions, 27oC at one meter depth sounds reasonable for Bangkok. There seems to be some relationship with ambient wet bulb. I hope some researchers can work on that. I agree with you, there will be no gain, going any deeper in Bangkok. Incidently,the same may not be the case in eastern sea board.
Now about 20% savings, let me guide you to a good report on the subject http://www.energy.ca.gov/reports/2002-01-10_600-00-023.PDF
The report cites the efficiency of evaporative condensing, where the evaporatively cooled air is the heat sink instead of the wet earth.
In Bangkok, earth as the heat sink has a temperature of say 27oC and the evaporatively cooled air may also have a similar temperature. darshi
Best always, Randy
PS is a latent heat pump a regular heat pump?
I've though long and hard about this. All we need is some engineer type inventor from bangkok to create a system using :
1) existing a de-humidifyer that can absorb the humidity from the air into liquid form.
2) use that liquid form water to spray into an evaporative cooler.
3) now evaporative coolers do not work in humid climates, because the water won't evaporate with the humid air. However this is where the de-humidified air at stage 1 comes in. The Dried Air, coupled with the sprayed water or water running down some coils, fins, threads, will definitely produce cooled air.
4) now if we could get all this into a box the size of current A/C units.
5) This will sell throughout all the humid tropical climates and earn heaps of money for the inventor.
This post is logged and dated so if someone tries to lodge a patent regarding this method... I was here first. Now get going and invent!
Oops. Pesky heat of vaporization/condensation problem. Condensing to a liquid form just trades latent heat for sensible heat. Now you've got dry air, but hotter.
> 2) use that liquid form water to spray into an evaporative cooler.
Atomizing the air requires pressurizing it, losing energy in the process.
> The Dried Air, coupled with the sprayed water or water running down some coils, fins, threads, will definitely produce cooled air.
True, but the problem is the energy you expended in condensing the water and pressurizing it so it can be atomized created more heat than you will remove through evaporation
> 4) now if we could get all this into a box the size of current A/C units.
I could build a nichrome wire that would act as a heater in a much smaller container than your apparatus, with identical results.
> 5) This will sell throughout all the humid tropical climates and earn heaps of money for the inventor.
So will my other perpetual motion machines. Would you like to buy a car that runs on water? I can sell you one of those too.
Damn laws of physics always gets in the way don't they? Maybe you could just ask the junta to suspend the second law of thermodynamics? Then your idea would be a smashing success...
Users browsing this forum: No registered users and 2 guests