Go Back   Team-BHP > Around the Corner > Shifting gears > Gadgets, Computers & Software


Reply
 
Thread Tools Search this Thread
Old 4th April 2013, 18:11   #2896
Senior - BHPian
 
Join Date: Sep 2007
Location: New Delhi
Posts: 3,079
Thanked: 251 Times
Default Re: Which home/office AC (air conditioner) to buy ?

Quote:
Originally Posted by Inquisitive View Post
....Now the way you can raise the dew point is by increasing the pressure within the room .....
Now Sharp is saying that they could increase the dew point by increasing the airflow. ....
The atmospheric pressure and air flow in a room are vastly different parameters!
There is no way for an air conditioner to change the barometric pressure in a room by even the tiniest bit!
anupmathur is offline   Reply With Quote
Old 4th April 2013, 18:13   #2897
Senior - BHPian
 
govigov's Avatar
 
Join Date: Oct 2007
Location: Cochin!!!!!
Posts: 1,287
Thanked: 389 Times
Default Re: Which home/office AC (air conditioner) to buy ?

Quote:
Originally Posted by Pancham View Post
Can anyone tell me how to understand whether my A.C is a R410.

I got my Samsung delivered yesterday. It's yet to be installed. Chose it over Daikin because I was not sure about the service network in Kolkata. Same reason for not choosing Sharp.
P.S. mine is a February 2013 manufactured model.
As far as I know, Samsung has not yet released an R410 model.
govigov is offline   Reply With Quote
Old 5th April 2013, 10:47   #2898
BHPian
 
Join Date: Dec 2012
Location: Kolkata
Posts: 89
Thanked: 52 Times
Default Re: Which home/office AC (air conditioner) to buy ?

Quote:
Originally Posted by anupmathur View Post
The atmospheric pressure and air flow in a room are vastly different parameters!
There is no way for an air conditioner to change the barometric pressure in a room by even the tiniest bit!
I agree and that is the reason why I referred you to their catalog. Did you have a chance to have a look? We must be missing something here.
Another option and I am purely guessing here, is that as because these are inverter models they can modulate the frequency of the compressor based on the humidity of the room. The compressor can make the cooling coil temperature close to the dew point. As more and more water vapor is removed from the system, the dew point comes down and the compressor reduces the cooling coil temp. As because the fan speed is high even when the dew point is high, the occupants will still be able to experience cool air however not from the fullest capacity of the compressor. Please give your opinion.
Inquisitive is offline   Reply With Quote
Old 5th April 2013, 15:47   #2899
Newbie
 
Join Date: Sep 2009
Location: bangalore, lexington
Posts: 8
Thanked: Once
Default Re: Which home/office AC (air conditioner) to buy ?

Quote:
Originally Posted by itwasntme View Post
Took the plunge here in Bangalore and bought a 1 TR Samsung 2* split for 22.4k (including standard installation) plus 2k for a V-Guard stabilizer. Sweetened the offer with a Citibank credit card deal for 0% interest plus no processing fees for 6 months!

Giving good results so far; real test to come very soon with the temperature rising. Overall, happy with my purchase.
Itwasntme, I installed a Samsung (Max Series) 1 ton 2* split as well a few days ago, however I feel it is not cooling adequately. My room is 150sq ft. What size room have you installed it in?
sandeepvr is offline   Reply With Quote
Old 5th April 2013, 17:10   #2900
BHPian
 
M5_fan's Avatar
 
Join Date: May 2010
Location: Noida
Posts: 99
Thanked: 18 Times
Default

Quote:
Originally Posted by sandeepvr View Post

Itwasntme, I installed a Samsung (Max Series) 1 ton 2* split as well a few days ago, however I feel it is not cooling adequately. My room is 150sq ft. What size room have you installed it in?
It is not cooling properly as you have taken an ac of the wrong capacity. For 150 sq feet you need a 1.5 ton ac. This is for tropical conditions like those in india.
M5_fan is offline   Reply With Quote
Old 5th April 2013, 22:07   #2901
Distinguished - BHPian
 
Thad E Ginathom's Avatar
 
Join Date: Jun 2007
Location: Chennai
Posts: 7,698
Thanked: 6,874 Times
Default Re: Which home/office AC (air conditioner) to buy ?

Quote:
Originally Posted by Inquisitive View Post
Please correct me if I am wrong. The dehumidification results in lower relative humidity in air and as a result one perceives lesser temperature. Now if an AC unit cooling the air automatically dehumidifies where will the condensed water go? Obviously it will condensate on the lowest temperature spot on the room that is on the cooling coils in the blower. The colder and dehumidified air is then released back into the room giving you the cooling effect. That is the relative humidity of the room is being controlled. Now what happens if you are instead using a dew point (temperature at which water vapor condenses into liquid form) control? Using a high dew point (consider any psychrometric chart, for the parameters that contribute) will result in removal of moisture at a higher temperature basically increasing your comfort level even at that point. Dehumidification also results in lowering the enthalpy (heat content) of the system that will also help in changes in temperature faster and efficient. High-efficiency air conditioners of these days use this trick to achieve better comfort level sooner.
(Sorry, I was off-broadband for two days --- and despite today's efforts by an Airtel engineer, am only unreliable back on)

i think you are confusing cause and effect here. It is the lowering of the temperature that causes the de-humidifying.

The only way to dehumidify without cooling would be by absorption.
Thad E Ginathom is offline   Reply With Quote
Old 5th April 2013, 22:39   #2902
Senior - BHPian
 
itwasntme's Avatar
 
Join Date: May 2007
Location: BANGALORE
Posts: 2,157
Thanked: 1,186 Times
Default Re: Which home/office AC (air conditioner) to buy ?

Quote:
Originally Posted by sandeepvr View Post
Itwasntme, I installed a Samsung (Max Series) 1 ton 2* split as well a few days ago, however I feel it is not cooling adequately. My room is 150sq ft. What size room have you installed it in?
Well, mine is around 120. What I have noticed is that the cooling is not as rapid as a 1.5 and takes a fair bit of time (even in Turbo mode). However, once cooling has happend, it effortlessly maintains the desired temperature. Having said that, haven't really used it extensively as its for our guest room.

Will try over the weekend and revert!
itwasntme is offline   Reply With Quote
Old 6th April 2013, 07:08   #2903
Senior - BHPian
 
Join Date: Sep 2007
Location: New Delhi
Posts: 3,079
Thanked: 251 Times
Default Re: Which home/office AC (air conditioner) to buy ?

Quote:
Originally Posted by Inquisitive View Post
....Please give your opinion.
My opinion stays unchanged.
There is nothing that an air conditioner can do to control the dew point in a room.
An air conditioner will cool and the relative humidity in the room will thereby reduce. All air conditioners will do the same thing and to almost exactly the same extent, provided the set temperature is the same.
An air conditioner with greater air flow will possibly achieve steady state quicker than one with lower air flow.
anupmathur is offline   Reply With Quote
Old 6th April 2013, 09:20   #2904
BHPian
 
Guite's Avatar
 
Join Date: Jul 2008
Location: Noida, NCR
Posts: 468
Thanked: 174 Times
Default Re: Which home/office AC (air conditioner) to buy ?

Quote:
Originally Posted by Inquisitive View Post
Now the way you can raise the dew point is by increasing the pressure within the room because other two options that is either increasing temperature or humidity will beat the purpose. Now Sharp is saying that they could increase the dew point by increasing the airflow.
Within a confined space served by an indoor unit AC, in which the unit is inside and part of that space, increase airflow will not increase pressure. It will just recirculate the same volume of air faster. If on the other hand air is pushed from outside, and exhaust is limited, pressure will build up.

As has been already stated by Thad and Anup, dehumidification is a by product of cooling air, not vice versa.
Guite is offline   Reply With Quote
Old 6th April 2013, 10:09   #2905
BHPian
 
Join Date: Dec 2012
Location: Kolkata
Posts: 89
Thanked: 52 Times
Default Re: Which home/office AC (air conditioner) to buy ?

Quote:
Originally Posted by Thad E Ginathom View Post
The only way to dehumidify without cooling would be by absorption.
I did not say ACs dehumidify without cooling.
Quote:
Originally Posted by anupmathur View Post
My opinion stays unchanged.
There is nothing that an air conditioner can do to control the dew point in a room....
I am in the process of understanding the basics of these new generation ACs. Somehow just searching in Google with 'dew point control air conditioning' generates a plethora of information.
Quote:
Originally Posted by Guite View Post
... dehumidification is a by product of cooling air, not vice versa.
actually vice versa because the heat content of the system will come down.
Inquisitive is offline   Reply With Quote
Old 6th April 2013, 15:50   #2906
BHPian
 
Guite's Avatar
 
Join Date: Jul 2008
Location: Noida, NCR
Posts: 468
Thanked: 174 Times
Default Re: Which home/office AC (air conditioner) to buy ?

Quote:
Originally Posted by Guite View Post
As has been already stated by Thad and Anup, dehumidification is a by product of cooling air, not vice versa.
Quote:
Originally Posted by Inquisitive View Post
actually vice versa because the heat content of the system will come down.
Your handle says you are residing in Kolkatta. Its humid out there. One fine summer day you pour a chilled cola into a glass tumbler. Shortly thereafter water drops form on the outside of the glass. So did the water formation cool the cola + glass or vice versa?
Guite is offline   Reply With Quote
Old 6th April 2013, 16:04   #2907
BHPian
 
Join Date: Dec 2012
Location: Kolkata
Posts: 89
Thanked: 52 Times
Default Re: Which home/office AC (air conditioner) to buy ?

Quote:
Originally Posted by Guite View Post
Your handle says you are residing in Kolkatta. Its humid out there. One fine summer day you pour a chilled cola into a glass tumbler. Shortly thereafter water drops form on the outside of the glass. So did the water formation cool the cola + glass or vice versa?
I refuse to answer this question because my response was meant for an adiabatic system. I hope you get what is meant. In the meantime I am attaching the research paper which described how higher airflow and reduction of latent load (humidity) works in an airconditioner. Thanks for everybody's interest and helping me learn something i did not have any beforehand knowledge.
Attached Files
File Type: pdf Ling 2008.pdf (229.4 KB, 472 views)
Inquisitive is offline   Reply With Quote
Old 6th April 2013, 20:21   #2908
BHPian
 
Dr.Vikas's Avatar
 
Join Date: Dec 2010
Location: Sangli
Posts: 107
Thanked: 32 Times
Default Re: Which home/office AC (air conditioner) to buy ?

Friends, any feedback on OGeneral ASGA 24 AET.. I already have bought 2 of these 2 ton split type ACs & about to install soon.. Would like to have tips/ instructions, if any..
Dr.Vikas is offline   Reply With Quote
Old 7th April 2013, 00:57   #2909
BHPian
 
Guite's Avatar
 
Join Date: Jul 2008
Location: Noida, NCR
Posts: 468
Thanked: 174 Times
Default Re: Which home/office AC (air conditioner) to buy ?

Quote:
Originally Posted by Inquisitive View Post
I refuse to answer this question because my response was meant for an adiabatic system. I hope you get what is meant. In the meantime I am attaching the research paper which described how higher airflow and reduction of latent load (humidity) works in an airconditioner. Thanks for everybody's interest and helping me learn something i did not have any beforehand knowledge.
The first line of the abstract immediately caught my attention. The key words are latent and sensible cooling. Their study concentrates on energy saving potential of getting it done by separate components. This is nothing new, it's already done. Let me give you an example.

An office design I have been involved in implements it but in a sequence opposite to what is described in that research paper. Latent heat of incoming outside air is first removed through a heat exchanger. The air is further cooled down sufficiently to bring down humidity level. However this air can be too cold so reheat process is applied. (Its been a long time ago, i don't remember all of it, I am not an HVAC engineer). These are handled by huge boxes sitting inside a plant room.

Data centre rooms require delicate control of RH levels and temperature. So the air ducted from plant room to data centre is further handled by high sensible cooling units, which cool down the air further without changing humidity level. Again these are cupboard size units. It's being done at large scale level, but can it be done at the home AC level in one small indoor unit? I am not sure.

I think you are quoting from third sentence of Conclusion section. Okay, so they have theoretically archieved energy saving by increasing airflow. In a ducted system you can control air speed at delivery point by designing the duct accordingly, but in a home AC of the type we have been discussing in this thread, the supply air will blast you literally.

This is not ground breaking research. Also note that their emphasis in on energy efficiency.

Now can we get back to: which came first....
Guite is offline   Reply With Quote
Old 7th April 2013, 20:32   #2910
Distinguished - BHPian
 
Thad E Ginathom's Avatar
 
Join Date: Jun 2007
Location: Chennai
Posts: 7,698
Thanked: 6,874 Times
Default Re: Which home/office AC (air conditioner) to buy ?

Inquisitive, I'm curious as to what you might have seen that applies to domestic AC systems, where control of humidity is an essential part of the process, but is done on a rough and ready basis: the humidity of the room is never controlled accurately, only the temperature. This is good enough for our homes, even though it might lead to dry skin and sore eyes. It may not be good enough for commercial plants (which also have to involve measured air change facilities) and it is certainly not good enough for environments where the moisture content of the air must be controlled precisely.

I have always been curious about the "Dehumidify" mode on my 7-yr-old Samsungs. No modern, high-tech there, just basic, temperature-controlled (the only sensors are thermostats) air cooling and drying. And, as is usual with basic split systems, no drawing in of external air.

So what is the "De-humidify" function doing and how? The only thing I can say about it is that it also seems (subjective sensing) to make the room colder! Maybe, somehow, it attempts to keep the temperature of the air below its dew point --- but I do not think it has any sensor sophisticated enough to know what that is.

.

Last edited by Thad E Ginathom : 7th April 2013 at 20:34.
Thad E Ginathom is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Automotive air conditioner servicing & maintenance vebmetal Technical Stuff 163 11th September 2017 19:10
Fitting an Air-conditioner in the Maruti 800 navdeep Technical Stuff 95 24th March 2012 17:07
Correct refrigerant level of a automobile air conditioner Sang Technical Stuff 6 15th May 2009 10:26
Best ROOM Air conditioner Max Shifting gears 2 3rd April 2006 09:52


All times are GMT +5.5. The time now is 11:50.

Copyright 2000 - 2017, Team-BHP.com
Proudly powered by E2E Networks