Multi Inverter Daikin Ac For Small House

[Phil Conners]

I need to install AC in a small house and it has been very interesting to read through some threads in this forum and learn about inverter AC's.

The house will need AC for 2 bedrooms of 12 and 16 m² and one 40 m² living room. We would normally not use AC in bedrooms and living room at the same time and aim for around 26C. Judging by this post that would be 7,000 + 9,600 + 24,000 BTU needed.

I understand that it's possible to have just one outside unit with 3 inside units? I really like this idea - I think there must be a lot of advantages with this - lower purchase and service price with just one instead of three units, for starters. I don't think I've ever seen this setup used in Thailand, any reason for that? Any reason not to go that route?

I think we would go with Daiken as it has a lot of people recommending it. As per this page that would mean 2 x 09 + 1 x 24 indoor units and one 28 outdoor unit. Does that make sense?

Any recommendations for a good company in Pattaya to do this?

[trogers]

Multi-system will cost more than single units combined. Practical only when you have restricted space to place the condenser units, like in Singapore government flats.

When the condenser breaks down, no air-con for all the areas. Not cost efficient to have a 28k btu condenser powering just a 9k fan coil at night, don't you think?

I have used both Daikin and Panasonic inverter units. The latter is cheaper but just as efficient.

[Naam]

I think we would go with Daiken as it has a lot of people recommending it. As per this page that would mean 2 x 09 + 1 x 24 indoor units and one 28 outdoor unit. Does that make sense?

it makes sense assuming the synchronous demand of the three indoor units does not exceed at any time the maximum ouput of the compressor/condenser unit which is 28k btu/h. it seems to me that the [lower] picture in the link does not show a combination of three indoor one outdoor unit but is meant for two indoor only.

personal opinion: you have fallen for the inverter hype without taking facts into consideration. the facts are that for the areas to be cooled you need rated capacity. inverters only save power if they are run much below rated capacity, i.e. the compressor rotates only based on demand and consumes electricity accordingly. manufacturers claim "up to 30% power savings" which is the optimum that can be achieved IF prevailing circumstances do exist.

most of the laymen recommendations from people who rave about their inverters and their power savings raise the hair on the back of my neck

p.s. Trogers presented one wrong assumption and a fact. if the demand on the outside unit is lower than its maximum capacity the DC driven compressor rotates accordingly slower and therefore power consumption is in line with demand. he is however right when stating "failure of outdoor unit = none of the indoor units will work".

pps. go for three individual conventional units. thanks for not listening

[Darrel]

"I understand that it's possible to have just one outside unit with 3 inside units?"

If I was doing it I would investigate the possibility of having a forced air cooling system:

One outdoor unit, one indoor unit, fan-driven vents to move the cool air around inside the house.

They do need to be installed by someone who knows what he is doing, but once in they are just one compressor and one internal unit, so maintenance is cheaper than for multiple units. As a bonus they are more or less silent in use.

Quite a few of my top-end customers in Europe had these systems.

[PattayaParent]

I don't think I've ever seen this setup used in Thailand, any reason for that?

There's a house on the estate I live in which has this system but with cassette type fan units but with the Daikin system you can use wall mounted or a combination of wall / cassette.

I'm thinking of putting one in my house as there will be a lot of rooms to cool and the condenser can handle a maximum of 8 units so will save having lots of individual condensers around the house.

Regarding the inverter power 'saving', does the extra cost of the inverter justify it? I only installed inverters in my flat becuase they were the same price as the conventional ones but otherwise wouldn't have bothered.

[lopburi3]

Such air duct systems may work in countries with hollow walls and good insulated ceilings with plenty of room for the duct-work but are not practical for most construction here.

[Darrel]

In Europe they often used 4in flexible insulated ducting which is quite easy to fit in the loft space (assuming there is a loft space), and ducts were sometimes buried in the concrete floor at the time of pouring it for buildings with only a ground floor. Obviously it does all depend on the nature of the building and any other work that is going on at the time. It should be practical in larger condos that have several rooms and false ceilings, for example. I've never liked those racks of aircon compressors one sees on balconies in some buildings, not to mention the noise from multiple compressors.

The end result is quite luxurious, with very good and uniform cooling in all rooms at will, and no indoor noise. I suspect that costs after installation were low also though I have no definite knowledge of this.

[Phil Conners]

Thanks for all the ideas and thoughts.

An airduct system is nice and above all quiet, the problem is I don't think anyone in Thailand know how to install one, it's just not a system that is used here. Even if one could be found it would probably be expensive due to low volume sales.

I presume that is also the reason why the "multipoint" system (for lack of a better term?) might be expensive here, it's not commonly used. I can not imagine why a single large compressor should be more expensive than 3 smaller. But it's probably the same as when you go to the supermarket and find that a 500g tub of something cost more than two 250g tubs.

@Naam - sorry I don't get your "sorry for not listening". I ask questions and I listen carefully to what everybody have to say. Of course in the end I make my own decision. Isn't that how it should be in your opinion?

Being half-technical, I can see the logic in having a compressor running continuously at low load is better than have it start and stop with full load, both for the wear and tear, the economy and the noise. The economy is only one of the advantages.

As I explained we would either be using the 24,000 BTU living room unit or the 2 x 9,000 BTU bedroom units, so a 28,000 BTU outside unit should be able to feed the system without problem.

As for the external unit breaking down causing complete failure of AC, I can see that point, however, I've never actually had a compressor fail on me in my 10 years in Thailand. I've had other minor problems but they have always been fixed within a few hours by the repair guys. I'm not really concerned about this possibility.

Cost is obviously an issue, but so are the other points, so it would really be down to specifics I guess.

[Naam]

@Naam - sorry I don't get your "sorry for not listening"

it was supposed to be a joke Phil, didn't you see my smiley? reason: my experience in TV-forum is that most people don't want to hear objective facts and prefer subjective fiction. if you do not belong to that category i humbly apologise. and if you don't take it as the joke i meant it to be... so be it.

[Naam]

I'm thinking of putting one in my house as there will be a lot of rooms to cool and the condenser can handle a maximum of 8 units so will save having lots of individual condensers around the house.

a compressor/condenser unit which can handle 8 units is three-phase. i know you live in the Pattaya area where quite often one or two phases conk off or have a brown-out (low voltage) your whole system is not to talk about burned out relays and starting capacitors.

[Naam]

Such air duct systems may work in countries with hollow walls and good insulated ceilings with plenty of room for the duct-work but are not practical for most construction here.

any single story Thai home has the loft space required. even in double story homes a duct system can be easily installed if planned accordingly during building phase. the problems to have a ducted system (as i know it from my other homes) are:

-no single phase big units available in Thailand, threephase connection required, problems as mentioned in my posting #10,

-no qualified companies (except perhaps BKK) which can install the system.

[PattayaParent]

I'm thinking of putting one in my house as there will be a lot of rooms to cool and the condenser can handle a maximum of 8 units so will save having lots of individual condensers around the house.

a compressor/condenser unit which can handle 8 units is three-phase. i know you live in the Pattaya area where quite often one or two phases conk off or have a brown-out (low voltage) your whole system is not to talk about burned out relays and starting capacitors.

Thanks for the info Naam, I hadn't fully looked into it as the house will actually be in Viet Nam and I'm told that the mains supply will be 2 phase so it sounds like a non-starter, literally.

[Phil Conners]

@Naam - sorry I don't get your "sorry for not listening"

it was supposed to be a joke Phil, didn't you see my smiley? reason: my experience in TV-forum is that most people don't want to hear objective facts and prefer subjective fiction. if you do not belong to that category i humbly apologise. and if you don't take it as the joke i meant it to be... so be it.

Yeah I saw the smiley, still didn't get it. Anyway, no problem, apology accepted.

[Naam]

Thanks for the info Naam, I hadn't fully looked into it as the house will actually be in Viet Nam and I'm told that the mains supply will be 2 phase so it sounds like a non-starter, literally.

i am not knowledgeable about the electricity system in Viet Nam. but it could be similar to the U.S. of A. where even big units are driven by a "single"-phase 220V (110V phase to phase instead of phase to neutral) supply. during my time in Saudi Arabia we had an identical system. surely you have the possibility to find out details?

[PattayaParent]

Thanks for the info Naam, I hadn't fully looked into it as the house will actually be in Viet Nam and I'm told that the mains supply will be 2 phase so it sounds like a non-starter, literally.

i am not knowledgeable about the electricity system in Viet Nam. but it could be similar to the U.S. of A. where even big units are driven by a "single"-phase 220V (110V phase to phase instead of phase to neutral) supply. during my time in Saudi Arabia we had an identical system. surely you have the possibility to find out details?

I plan to visit the Daikin dealer when I am next there Naam to get details of the systems and power requirements etc. I've emailed them but had no response.

[aussiebebe]

My condo had three non-inverter air-conditioners fitted when I bought it; two 9kBTU units for two bedrooms, and a 12kBTU in the living room - reading this thread made me wonder whether a Daikin super multi inverter might look nicer and save money so I emailed Daikin and they replied swiftly;

Indoor Wall type CTKD09GV2S 9,000 BTU 8,400 Baht, CTKD09GV2S 9,000 BTU 8,400 Baht, CTKD12GV2S 12,000 BTU 10,500 Baht

Outdoor 3MKD28GV2S 25,600 BTU 54,100 Baht

I'll certainly consider such a system in the future when I come to replace my existing units; typical prices I've seen for non-inverter units are 14k for 9kbtu and 18k for 12kbtu whereas inverters are quieter and maintain a more constant temperature. If it saved 30% of my monthly bill - which is 600baht - the break-even period would be under 5-years with the Daikin super multi inverter unit (based on current electricity prices).

[Naam]

If it saved 30% of my monthly bill - which is 600baht - the break-even period would be under 5-years

the big "IF"! depending on the heatload on your bedrooms and the living room inverters might save you 0% because their [undisputed] advantage applies only to specific cases. honest manufacturers claim "up to" 30% savings, a clear indication that generally the savings are much less. unless the rooms you are cooling are not tiny and you aim for a comfortable temperature of 26-27ºC in a tropical environment like Thailand your present capacity seems to be just sufficient to meet the demand, id est savings by inverter units = zero.

moreover, if your monthly electricity bill is 1,800 Baht then you must deduct the consumption of your non-aircon electric gadgets and then try to estimate the percentage of inverter savings based on that balance. last not least a correct calculation of break-even period has to include loss of interest due to blocked capital.

[aussiebebe]

If it saved 30% of my monthly bill - which is 600baht - the break-even period would be under 5-years

the big "IF"! depending on the heatload on your bedrooms and the living room inverters might save you 0% because their [undisputed] advantage applies only to specific cases. honest manufacturers claim "up to" 30% savings, a clear indication that generally the savings are much less. unless the rooms you are cooling are not tiny and you aim for a comfortable temperature of 26-27ºC in a tropical environment like Thailand your present capacity seems to be just sufficient to meet the demand, id est savings by inverter units = zero.

moreover, if your monthly electricity bill is 1,800 Baht then you must deduct the consumption of your non-aircon electric gadgets and then try to estimate the percentage of inverter savings based on that balance. last not least a correct calculation of break-even period has to include loss of interest due to blocked capital.

Hi, I agree with all your points, I shouldn't have guessed so crudely - I've never owned an inverter, I've no idea what they really save. I just guessed 1800 from my 2600 bill, but I don't know what % is air con, I'd need to fit one of those 'smart meters' (don't even know where to buy one) to work how much each appliance really costs.

Good point about loss of interest; I don't even know how to calculate the potential break-even period, isn't it complex!

cheers

[Naam]

I'd need to fit one of those 'smart meters'

that won't help because they only measure actual present consumption but not accumulated for several months. but whatever... the percentage of aircon electricity consumption can vary tremendously. e.g. there's a huge difference between living in a condo or a house, the latter with electricity needed for pool, pond, irrigation, house watersupply, deep well, outside lighting, etc. and last not least to what extent (desired temperature for what size area) aircon is used.

no rule of thumb applies and comparisons are totally worthless because nearly every case is unique. i have people coming to my house who complain that 26ºC is too cold and others who complain that it's much too hot.

[Phil Conners]

There are meters you can attach permanently or temporarily, that will link to a computer and/or the internet and give you long term details and stats for your consumption, for example this clever little gadget.

Any opinion on 5 Plus Technology? As I understand it, it's supposed to lower your power consumption and increase the cooling power of AC units through some added valves.

[Naam]

1. There are meters you can attach permanently or temporarily, that will link to a computer and/or the internet and give you long term details and stats for your consumption, for example this clever little gadget.

2. Any opinion on 5 Plus Technology? As I understand it, it's supposed to lower your power consumption and increase the cooling power of AC units through some added valves.

1. it would be fun to watch a layman trying to "clamp-amp" measure power consumption of a hardwired aircon unit.

2. my Thai is limited to a few polite spoken sentences. that's why i could not find in the description in which valve the snake oil has to be poured.

[Phil Conners]

1. Why? I've seen the system in use, it is very easy to set up.

2. As I understand it the idea is something to do with the pressure falling when the compressor goes off, then when it starts again it has to start building up the pressure first before the cooling process can start. The valves somehow keeps that pressure high so reduce the loss by the lost pressure. But I could be wrong on that.

[JimSiam]

1. Why? I've seen the system in use, it is very easy to set up.

2. As I understand it the idea is something to do with the pressure falling when the compressor goes off, then when it starts again it has to start building up the pressure first before the cooling process can start. The valves somehow keeps that pressure high so reduce the loss by the lost pressure. But I could be wrong on that.

It changes the whole gas flow principle of the system, mainly in the off cycle, the main points are:

• In the off cycle it balances compressor output pressure to around 60psi to provide a real soft start.
  
• It prevents the gas from turning to liquid before the compressor in off cycle, in a normal unit the liquid build up takes 45 seconds to convert back to gas before cooling occurs when the compressor comes back on.
  
• It stops the hot gas from the compressor from entering the indoor unit in the off cycle providing a smaller variance in humidity and keeps the indoor unit cool longer.
  

Edited January 11, 2012 by JimSiam

[Naam]

1. Why? I've seen the system in use, it is very easy to set up.

2. As I understand it the idea is something to do with the pressure falling when the compressor goes off, then when it starts again it has to start building up the pressure first before the cooling process can start. The valves somehow keeps that pressure high so reduce the loss by the lost pressure. But I could be wrong on that.

1. how does a layman find the wiring for a certain aircon to apply the clamp? easy to measure any other gadget which is plugged with a cable into an outlet. aircons are not, at least never saw one connected like this.

2. a starting compressor draws a multiply of amps against zero system pressure. if pressure existed when starting then this multiple would increase exponentially with disadvantages which are not really important to explain now. that's why all aircons have a timer which does not allow a compressor until zero system pressure exists. these timers are normally set for a 5 minute delay.

[Phil Conners]

1. Just go out to the compressor and locate those fat cables with the power, they're usually on the side of the AC. I really don't think that ought to be an issue.

2. Well as I said, I'm not sure I understand how it works, only that some technical institute says it's good

[Naam]

1. Just go out to the compressor and locate those fat cables with the power, they're usually on the side of the AC. I really don't think that ought to be an issue.

2. Well as I said, I'm not sure I understand how it works, only that some technical institute says it's good

1- the wiring of all my units is piped.

1a- some outside units are only accessible with ladders.

2- some technical institute...

[Naam]

5 Plus Technology is the technology invented by Thai.

It had been well-proven by NECTEC (Ministry of Science & Technology) and Department of Renewable Energy Development (Ministry of Energy) that it can save energy on air-conditioning that operate on part load in between 15% to 40%. In addition, this technology can enhance cooling capacity on the same air-conditioning units and prolong compressor’s life time, either. It is the mechanical parts unlike other technologies that are electronics based. Therefore the operating and maintenance of this technology is so little.

http://www.eci-inter.co.th/5plus.html

Your Honour, Ladies and Gentlemen of the Jury... i rest my case.

[Phil Conners]

1. Just go out to the compressor and locate those fat cables with the power, they're usually on the side of the AC. I really don't think that ought to be an issue.

2. Well as I said, I'm not sure I understand how it works, only that some technical institute says it's good

1- the wiring of all my units is piped.

1a- some outside units are only accessible with ladders.

2- some technical institute...

1. This diagram shows how you do. I can not imagine there not being a 1 cm gap somewhere where you can clamp it.

2. Actually it was "NECTEC (Ministry of Science & Technology) and Department of Renewable Energy Development (Ministry of Energy)". Sorry for calling it "some technical institute"

5 Plus Technology is the technology invented by Thai.

It had been well-proven by NECTEC (Ministry of Science & Technology) and Department of Renewable Energy Development (Ministry of Energy) that it can save energy on air-conditioning that operate on part load in between 15% to 40%. In addition, this technology can enhance cooling capacity on the same air-conditioning units and prolong compressor's life time, either. It is the mechanical parts unlike other technologies that are electronics based. Therefore the operating and maintenance of this technology is so little.

http://www.eci-inter.co.th/5plus.html

Your Honour, Ladies and Gentlemen of the Jury... i rest my case.

Sorry, and this proves exactly what?

[Naam]

Sorry, and this proves exactly what?

it doesn't prove anything but indicates everything.