1 Air-con To Cool 2 Rooms

[jaideeguy]

Wondering if it is possible to use one outside compressor unit to cool 2 side by side rooms [separated by a 4" hollow block wall] and have two inside distributor units, one in each room. Of course, they wouldn't both be on at the same time. one is a bedroom, occupied at night and the other is office used during days. compressor would be mounted mic way, so no excessive lengths of tubing.

Can do?? maybe need valves to isolate units??

[ProThaiExpat]

Seems to me that a simple Y in the compressor line to the distribution units would work. The unit that is on would pull the compressors output and the one not on would block escape of compressor output.

Arched openings across the room from the aircon unit into an adjacent room also works to allow one unit to service two rooms. A door there would be problematic.

[Naam]

Wondering if it is possible to use one outside compressor unit to cool 2 side by side rooms [separated by a 4" hollow block wall] and have two inside distributor units, one in each room. Of course, they wouldn't both be on at the same time. one is a bedroom, occupied at night and the other is office used during days. compressor would be mounted mic way, so no excessive lengths of tubing. Can do?? maybe need valves to isolate units??

valves will not do the trick as the compressor will get "liquid hammer" if one unit is switched off (if the compressor is meant to serve two units at the same time). the only way is an outside compressor/condenser unit with a variable speed compressor. i doubt very much that these units are available in Thailand and if they are then they will be as expensive as two smaller units. even the available inverter units (where the compressor runs at variable speeds) won't do the trick as speed reduction is only down to 70% and not the required 50%.

what is available are single outside units which contain 2 or 3 compressors with individual connections to the inside units.

a "y"-connection is impossible as there is a pressure and a suction line and without solenoid valves the compressor wouldn't "know" to which unit to pump and from which unit to suck refrigerant. but even with solenoids a variable speed compressor is mandatory.

there is however a technical way to overcome the problems by using an adjustable by-pass valve but i refrain from an explanation as you will hardly find anybody in Thailand able to build such a system and the problem of liquid hammer would still not be solved.

edited to make german grammar readable

Edited February 13, 2008 by Naam

[Naam]

You could do it with a T after the compressor unit. You will have to install a selonoid valve going to each unit and manualy flip a switch when going from one unit to the other, Also put check valves in both suction lines. It is Important that you wire the valves in series so that one is n/o open the other is n/o closed . When you flip the switch they will reverse them selfs .The problems you may incounter is that you will not be able to control the temp.depending on the the way the system is set up. Also oil managment could be a problem so make sure that you check the oil in the compessor the first couple of times you go back and forth. Also make sure you put a vacuam pump on the system for 24 hours and check for leaks before adding freon . Good luck !

LORD HAVE MERCY! how do you check the oil in a sealed unit? with a dipstick?

[lopburi3]

There are units designed for more than one room available (and have been) for as long as I can remember. The current Daikin inverter model being heavily advertised currently can be used with up to three inside units.

Now if you wish to set up a whole house/hotel with independent units perhaps a chiller (water cooled) system would be best.

[Gary A]

I was renting a small two bedroom house. Only the bedroom had air conditioning. When it was really hot, I opened the bedroom door and used a fan to move air into the living room. That worked good enough that I didn't feel the need to buy another unit. I wouldn't recommend trying to run two evaporators off one compressor.

[jaideeguy]

Interesting.......lotsa conflicting info, keep the comments flowing and I'll decide when the 'dust' settles, hopefully before it gets too hot!!

Thanks...

jdg

[tutsiwarrior]

I was renting a small two bedroom house. Only the bedroom had air conditioning. When it was really hot, I opened the bedroom door and used a fan to move air into the living room. That worked good enough that I didn't feel the need to buy another unit. I wouldn't recommend trying to run two evaporators off one compressor.

in the Middle East I've lived in places with noisy window units. At night I'd keep the bedroom unit turned off because of the noise and the cold air from the next room with the unit on full blast was enough to stay comfortable.

[dickie58]

I was renting a small two bedroom house. Only the bedroom had air conditioning. When it was really hot, I opened the bedroom door and used a fan to move air into the living room. That worked good enough that I didn't feel the need to buy another unit. I wouldn't recommend trying to run two evaporators off one compressor.

in the Middle East I've lived in places with noisy window units. At night I'd keep the bedroom unit turned off because of the noise and the cold air from the next room with the unit on full blast was enough to stay comfortable.

There are a number of the air-con companiees who make a split system, that can run two house indoor units of one compressor, the negative side is if the compressor goes you loose use of both units.

Split systems are also very expensive, cheaper to buy two seperate units

[Naam]

By looking in the round sight glass hole located in the lower section of the compressor. When the unit is running the oil level should not be higher than the middle of the glass. You may need a flash light to see it splashing around . I HOPE YOU ARE NOT IN THE REFRIGERATION BUSINESS

thanks God i'm not and i hope for the sake of some customers you are neither to the best of my knowledge even the biggest manufacturer Tecumseh does not produce compressors with a sight glass below a capacity of 2 tons/24k btu.

You could do it with a T after the compressor unit. You will have to install a selonoid valve going to each unit and manualy flip a switch when going from one unit to the other

that works in theory only. the problem of the compressor pumping liquid and gets damaged still exists if one unit is switched off and evaporation goes down 50%. it would be different if JaideeGuy wants to run only one unit at a time and the compressor's capacitiy is matched serving one unit.

Also make sure you put a vacuam pump on the system for 24 hours

right you are IF you can find a thai installer that leaves a vacuum pump for 24 hours in your home after installation.

[jaideeguy]

"There are a number of the air-con companiees who make a split system, that can run two house indoor units of one compressor, the negative side is if the compressor goes you loose use of both units.

Split systems are also very expensive, cheaper to buy two seperate units "

How much more expensive?? can i use my old 'inside' unit in office room and the new 'inside' unit in my bedroom?? would they be compatable??

"it would be different if JaideeGuy wants to run only one unit at a time and the compressor's capacitiy is matched serving one unit."

jaideeguy DOES want to run only one unit at a time, as stated in OP.

[Naam]

"There are a number of the air-con companiees who make a split system, that can run two house indoor units of one compressor, the negative side is if the compressor goes you loose use of both units.

Split systems are also very expensive, cheaper to buy two seperate units "

How much more expensive?? can i use my old 'inside' unit in office room and the new 'inside' unit in my bedroom?? would they be compatable??

"it would be different if JaideeGuy wants to run only one unit at a time and the compressor's capacitiy is matched serving one unit."

jaideeguy DOES want to run only one unit at a time, as stated in OP.

this discussion is academic JDG. try to explain to a couple of a/c installers what you would like to have, mention solenoid valves and observe their reaction. and when you are p*ssed off enough spend the dough for two units, save yourself a huge headache and live in peace

[jaideeguy]

Yes, it can be done and someone is doing it!!!

Thru another post that i had going, i got a lead on just what i'm looking for....one comperssor to cool several rooms if anyone is interested check this site out......

http://www.daikin.com/global_ac/products/r...ti/outline.html

don't know what prices will be, but expect them to be quite pricey with the 'daikin' brand name. will check with the local daikin dealer this week to check and post what i find.

[Naam]

Yes, it can be done and someone is doing it!!!

nobody said it can't be done. what was said is that it should be done in a proper way and not the way we used to do setups in the african bush a couple of decades ago.

[jaideeguy]

"Now if you wish to set up a whole house/hotel with independent units perhaps a chiller (water cooled) system would be best. "

Maybe someone could explain the chiller water cooled system to me in simple english........

and the initial cost and operating costs as compared with normal compressor units???

[chownah]

A chiller system has a central place where a compressor with refrigerant type cooling system (usually it uses this type of system) is used to cool water....the water is then circulated around to the various rooms which one wishes to cool where it flows through radiator-in-a-box like things with fans which blow the cooled air from the radiator box into the room...the radiator box is called a "fan coil".

Chownah

[Naam]

"Now if you wish to set up a whole house/hotel with independent units perhaps a chiller (water cooled) system would be best. "

Maybe someone could explain the chiller water cooled system to me in simple english........

and the initial cost and operating costs as compared with normal compressor units???

chillers are only available in bigger capacities than for 3-units. advantages are that the plumbing for the circulating water is no hi-tech and cane be done by any plumber. another advantage is that length of piping does not matter (if properly insulated) when a correct pump size is used. the operating cost does not differ from units which use refrigerant to the inside units. however, operating cost are substantially lower when the condenser unit is water cooled two and own well water is available. the latter meaning you have three cycles:

1. water from heat exchanger chiller via water pump to inside units.

2. refrigerant from chiller evaporator via compressor to chiller condenser.

3. water from well (or any other source) via water pump to and from heat exchanger condenser.

another advantage of water/refrigerant/water-chiller units is that they don't have to be located outside.

nota bene: the average thai aircon contractor has no bloody idea about chillers! those who are knowledgeable are in the commercial business and do not care about the needs of Jaideeguys or Naams.