Air conditioning - Any recommendations please??

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fantasticfox

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could anyone advise which FCU offers the quietest operation? i am very particular about fan noise, unfortunately. ;)
 

cacafoo

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Hi,

I like to check is it worth to upgrade System 3 aircons from G24 copper pipe to G23, 13mm drainage to 16mm? The price difference is abt $210.

Thanks
 

felali

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Clarification on Air-Con combinations

Hi Terumo,

May I ask for a clarification on the aircon indoor unit combinations that manufacturers put on their catalogs?

I'm confused about the numbers listed on the multi-split combination tables such as below. They list the maximum cooling capacities when different indoor units are combined together.

Take a look at the model/combi highlighted below, the biggest indoor fan unit cools up to 6.0kW (i guess about 20.5k BTU/hr?) alone with this compressor. But when the same indoor unit is combined into a sys2, it goes down to 4.73kW, and down to 3.65kW when put in a sys3 combo.

Does that 4.73kW and 3.65kW number refer to:
1) the maximum cooling capacity of this indoor unit when ALL split units are simultaneously switched ON to maximum, or
2) the maximum cooling capacity of this indoor unit, even though all the other split units are switched OFF?

Researching now for air-con for living room, but likely to split it with at least a study room or more. It doesn't make sense for the cooling capacity to drop just because of multi-split (provided all others turned off), but I thought I better clarify with you.

Thanks!!

Air-ConCombinations1_zpsfeeb74fb.png

(taken from Mitsubishi Heavy Industries, Ltd.)
(panasonic also has a pdf catalog Product Catalogues)
 
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felali

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Long version (but excellent) BTU calculator

Pretty interesting stuff. One thing we often forget is for every X watts of electricity an appliance needs, the air conditioner works X watts (i.e. 3.5 BTU) harder to remove the heat.

For example, if you use your 1500W hair-dryer in your air-con bedroom, it generates 5250BTU/hr of heat that your air-con needs to remove. That's almost 60% of the maximum your average 9k BTU aircon can handle!! Ouch!

Taken from:AC, Calculating air conditioner size - Grasscity.com Forums

Simpler (local) version: http://catalog.wokeehong.com.sg/aircon_cc_calculator/aircon_cc_calculator.html

Calculating Heat Load:
Heat is measured in either BTU or Kilowatts. 1KW is equivalent to 3500BTUs.
The heat load depends on a number of factor's

1.The floor area of the room
2.The heat generated by equipment
3 the heat from lighting
4.The number of room occupants
5.The ambient temp (your room's starting temp)

1.Floor Area of Room

Room Area BTU = L x W x 40 ( H = 8foot + 5btu per foot after that)

If you have a wall that is facing the sun add in for the extra heat

Sun facing wall BTU = L x H x 40

2.Equipment
This is trickier to calculate than you might think. The wattage on equipment is the maximum power consumption rating, the actual power consumed may be less. However it is safer to overestimate the wattage than underestimate it.

Equipment BTU = Total wattage for equipment x 3.5

Ballast in room BTU = ballast wattage/2 x 3.5

3.Lighting

Lighting BTU = Total wattage for all lighting x 4

Air cooled hood BTU = wattage x 4 / 2
@
400= 200-250 cfm
600= 250-300 cfm
1k = 300-350 cfm
^ is just a guide cfm per hood will be on your ducting/SP....

4.Occupants
even being that im only there for 2 or so of the 12 hrs i like it to be able to handle the extra sweat when i smoke one.

Total Occupant BTU = Number of occupants x 400

Total Cooling Required

Add all the BTUs together.

Total Heat Load = Room Area BTU + Total Occupant BTU + Equipment BTU + Lighting BTU

If your using a portable a/c:

Total Heat Load BTU x 2

^this has been from threads if you are planning on getting one i think one that's bigger then you thought about


sample

so if we have a 3 x 3 room with 1k and 200 watt's in fan's/pump's

for room we need 360 btu
for fan we need 700 btu
1k = 4000btu
ballast in the room = 1500 btu

we would need a/c that is 6560 btu i would round up to the next size 7kbtu


air exchange
aka intake/exhaust
complete air exchange every 4-5 minutes is average for a grow room/greenhouse (co2 control)....
for heat control (no a/c) i like to use 2.5 minutes {1M is best imo}
m=air exchange in min's

l x w x h = cf / m = cfm

lets use are room from above as a sample
3 x 3 x 8 = 72 /2.5 = 28.8 (30)
highend turn over = 72cfm
lowend turn over = 30cfm
now for the light 1k = 300-350cfm

exhaust system and air-cooled hood should be separated but most ppl cant/dont ( it's spendy) so add them together if your using 1 fan for both

the fan size we need is 330-422 remember you have duct loss (SP) in the sample room i would use a 440 cfm fan

SEER & EER ratings NO they are not the same.....

EER, or the Energy Efficient Ratio, is a measure of how efficiently a cooling system will operate when the outdoor temperature is at a specific level - usually 95°F. EER is calculated as a simple ratio of BTU's to the amount of power a unit consumes in watts. Here is an example using an air conditioner with 12,000 BTU's and consuming 1500 watts of power:

EER = BTU's / Watts

12,000 / 1500 = 8

EER = 8


While it is true that the higher the EER and BTU's, the more efficient the cooling system, many make the mistake of purchasing oversized air conditioners and ignoring EER ratings. The following is an example of an air conditioner with 12,000 BTU's and 1200 watts:

12,000 / 1200 = 10

EER =10

This would mean that this second unit can produce the same amount of cooling but more energy efficiently. Therefore, to save money on your monthly electric bill, choose a cooling system by getting an appropriately sized unit with a high EER.

I'm not taking credit for all this info.
 
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felali

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Air-con electrical bill savings calculator

Ever wanted to figure out how whether electrical bill savings from an inverter air con is worth the extra price you pay for the unit?

Check out the excel file at http://www.energystar.gov/ia/busine...s_calc/CalculatorConsumerRoomAC.xls?4490-833b
(searchable from Energy Star website ENERGY STAR)

You will need to find out:
1) the efficiency of your desired air conditioner. Usually given in terms of EER or COP.
2) the exact BTU of your air-conditioner

Current local tariff = $0.267/kWh
EER/COP conversion (1 COP = 3.412 EER)
BTU/hr to kW conversion (1kW = 3412 BTU/hr)

Not sure how many hours the excel file is calculating for an annualized energy cost estimate, but can always go dig out from the excel file...

At the end, its probably a rough number estimate, but confirm still better than kena smoke by salesmen... Heh
 

felali

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could anyone advise which FCU offers the quietest operation? i am very particular about fan noise, unfortunately. ;)
Uh, based on my layman research comparing Mitsubishi Heavy Industries and Panasonic,

For 9k BTU units, the MHI is much much quieter than the Pansonic. (MHI 21-34 dbA vs Pana 29-40 dbA)

For 21k BTU units, they are both similarly noisy under load. (MHI 26 - 46 dBA vs Pana 38 - 47 dBA)

(based on downloadable pdf brochures from their sites, I pasted the links a few posts above)
 

jmkeong

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Mit StarMex Sys 3 MS-A10VD x 3 & MUX-3D23VD

Hi Experts,

Greetings to all. Newbie here, really appreciate your urgent advise.

Just bought a resale flat and DIY almost all that I with furniture in recently. Realised that the previous owner smoked me saying that the ac was only 1yr+ which in fact when I checked with Mit agent, it was coming 5yrs already when I noticed that the mbr was not cold at all and compressor not running. :(

Called in a svc guy to check, open up the trunking and found no leak, the pipe length is only <5m (<3m in-door upwards & <2m out-door to my compressor). Gas was completely 0 and so he tried to tighten everything and pump in gas and did a general svcing. It was cold and everything was perfect. But less than on-ing a few times, it's losing its coldness. Set to 25 but when compared to the other 2 rms with same setting,the other 2 rms were cold.

Was on tight budget and did not cater for ac, tried opening up the cover and noticed around the u-shaped copper coil going in and out the fins were badly corroded. When ac on, the incoming pipe surface freezes and then defrost and condensation starts after running for a short while. Near the bottom of the right fins, there seems to have some whitish substance suggesting a gas leak? Else, everything looks and sounded fine. Can I just change the fins (cooling coil) or worst the whole blower unit since the blower model is still available? 1 of the common rm blower is also showing signs of corrosion. the other common rm blower was like brand new as the previous person in that rm did not use ac.

What will the damage if I decide to change the 2 cooling coils or whole blower unit and maybe also run a new piping for my mbr? Anyone can recommend who to look for as my ac svc guy only does general svcing.

Really look forward to experts' advise as I cannot afford to change the whole sys and also re-paint the hse.
 

tnecniv

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anyone using midea air con? i would to know how is it? im thinking of gettng the single split non inverter. 6yr compressor warranty from courts nw @ 699 + brackets 130+ power src 200. what do i need to lookout for during installation and purchase as this is my house first air con.
 

terumo

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cacafoo,

G23 is usually the standard for materials used.
G24, i will not suggest u use it.
 

terumo

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to felali,
Scm60 is around 6.0kw ~ 21000 btu.
When they put 25+25+60, its for all units on @ the same time.
When they put 25+60 its 2 units on at the same time.

When u connect the 60 fcu to the 60 outdoor unit, it will produce the max btu, but when u add another unit say 25, the 60 will drop to provision for the 25 as the 60 outdoor unit need to support the 25 as well.
 

terumo

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the white substance u saw should be ice forming, when gas is low/shortage, icing will occur.
Have to do a pressure test to determine where is the leak rather then changing the blower unit based on visual/physical outlook.
 

jmkeong

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the white substance u saw should be ice forming, when gas is low/shortage, icing will occur.
Have to do a pressure test to determine where is the leak rather then changing the blower unit based on visual/physical outlook.
Hi Terumo,

The icing appears only at the incoming pipe for a couple of secs. The whitesh on the fins seems like some chemical residue only at 1 section. But still, would like to change the cooling coil or blower since I'll be staying there for at least 5yrs, the coil definitely cannot last that long looking at the state of the corrosion. Any idea the cost for coil or blower & who can offer and do it?
Thanks in advance again.
 

felali

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to felali,
Scm60 is around 6.0kw ~ 21000 btu.
When they put 25+25+60, its for all units on @ the same time.
When they put 25+60 its 2 units on at the same time.

When u connect the 60 fcu to the 60 outdoor unit, it will produce the max btu, but when u add another unit say 25, the 60 will drop to provision for the 25 as the 60 outdoor unit need to support the 25 as well.

Thanks!

So even when I have 25+25+60, but if both the 25+25 are switched OFF, I'm able to get 6kW?
 

jmkeong

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Hi Terumo,

The icing appears only at the incoming pipe for a couple of secs. The whitesh on the fins seems like some chemical residue only at 1 section. But still, would like to change the cooling coil or blower since I'll be staying there for at least 5yrs, the coil definitely cannot last that long looking at the state of the corrosion. Any idea the cost for coil or blower & who can offer and do it?
Thanks in advance again.

Have just check with agent, the whole blower unit is $200/each incl GST. I would like to change 2 units of blower and for the mbr, re-run the piping which is <5m long. Any reliable installer to recommend?
 

terumo

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to felali,
if u use 60 alone with the 25 x 2 off, yes u r able to get 6Kw.
 

tnecniv

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Cover up holes

Hi i just made my purchase for my room air con. The thing is that my house is old house and there are "Holes" above my room door, some kind of design. anyone has any good and cheap ideas to cover up the room?
 

Akai Ryu

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Hi i just made my purchase for my room air con. The thing is that my house is old house and there are "Holes" above my room door, some kind of design. anyone has any good and cheap ideas to cover up the room?

DoorSweep-Sm.jpg
 
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