6.5 HP air conditioning system

[<ramrod]

Some time back someone asked about one of my system here in my home in the tropics in Queensland Australia.

So here is some data I logged today.

I was actually charging the unit after repairing a leak (darn O rings !) So while charging it up I logged some data

We have had a few weeks of day maximums of around 34 c temperatures (around

93 f). Humidity 55 to 60 % so the house is fairly hot, being a brick home.

We are approaching the wet season and so the weather will get a bit hotter and more humid.

The system is a Carrier 06DA818 compressor (6.5 hp) with a slightly oversized condenser to keep the head pressure low.

The fan coil unit is sold as a 4 to 6 ton unit. Both the condenser and the fan coil units were made here in Australia, so quoting model numbers would be a waste of time.

So today I ran these tests, it was a bit slow in cooling down the are conditioned area as I was charging it at the time.

The refrigerant is R22.

In the lounge there is a 6 foot x 2 feet x 2 foot aquarium which the water in it was about 33 c (about 90 f) which means it radiated heat to be removed by the air conditioning unit.

The cooling was set for 25 c (about 77 f) the original temperature in the lounge and kitchen that are service by this system was 32 c (around 89 f) and 70% RH. It took around one and half hours to cool down to the set temperature. Both the lounge are and the kitchen area are large rooms.

OK the readings were.

Outside air

34 c (around 93 f)

Humidity outside Around 65 % RH

Suction pressure 75 PSI Discharge pressure 240 PSI Oil pressure 20 PSI

Current draw on the compressor was around 9 amps per phase (415 volt, 50 cycles)

I estimate the cooling capacity of this system to be around 75, 000 BTUs, (around 6.25 tons) based on the compressor capacity

The condenser has 2 x 3 phase fans motors on it and I have set them up to run on star and also delta giving head pressure control the star being slower and delta faster, there are 4 pressure switches to say which fan runs how. The condenser is a bit oversized to keep the head pressure down.

The duck work is pretty generously sized to give reasonable air quantities and quiet air flows.

I had to put a larger evaporator fan motor in to get the right amount of air.

My business used to make our own fan coil units but alas I sold off all the gear years ago before installing this system.

Hey I had to get the system going so we would have a cool area for Christmas dinner, enjoy yours.

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[Grumpy]

Some time back someone asked about one of my system here in my home in the tropics in Queensland Australia.

So here is some data I logged today.

I was actually charging the unit after repairing a leak (darn O rings !) So while charging it up I logged some data

We have had a few weeks of day maximums of around 34 c temperatures (around 93 f). Humidity 55 to 60 % so the house is fairly hot, being a brick home.

We are approaching the wet season and so the weather will get a bit hotter and more humid.

The system is a Carrier 06DA818 compressor (6.5 hp) with a slightly oversized condenser to keep the head pressure low.

The fan coil unit is sold as a 4 to 6 ton unit. Both the condenser and the fan coil units were made here in Australia, so quoting model numbers would be a waste of time.

So today I ran these tests, it was a bit slow in cooling down the are conditioned area as I was charging it at the time.

The refrigerant is R22.

In the lounge there is a 6 foot x 2 feet x 2 foot aquarium which the water in it was about 33 c (about 90 f) which means it radiated heat to be removed by the air conditioning unit.

The cooling was set for 25 c (about 77 f) the original temperature in the lounge and kitchen that are service by this system was 32 c (around 89 f) and 70% RH. It took around one and half hours to cool down to the set temperature. Both the lounge are and the kitchen area are large rooms.

OK the readings were.

Outside air 34 c (around 93 f)

Humidity outside Around 65 % RH

Suction pressure 75 PSI Discharge pressure 240 PSI Oil pressure 20 PSI

Current draw on the compressor was around 9 amps per phase (415 volt, 50 cycles)

Sir your pressures' look great but I do have problem with your power is this unit 3 phase 415/3/50 or single phase 415/1/50, because if you have power of single phase two wire power supply your system is "not" more then about 3.5 tons or 42,000 btu, and not 6.25 tons. Based on your power consumption of 9 amps. I am not AC person but I am Refrigeration Tech. I am puzzled little with your power info. Normally 440-60 hrz is run on 380-50 hrz but as you said it is manufacture there so?

I estimate the cooling capacity of this system to be around 75, 000 BTUs, (around 6.25 tons) based on the compressor capacity

The condenser has 2 x 3 phase fans motors on it and I have set them up to run on star and also delta giving head pressure control the star being slower and delta faster, there are 4 pressure switches to say which fan runs how. The condenser is a bit oversized to keep the head pressure down.

The duck work is pretty generously sized to give reasonable air quantities and quiet air flows.

I had to put a larger evaporator fan motor in to get the right amount of air.

My business used to make our own fan coil units but alas I sold off all the gear years ago before installing this system.

Hey I had to get the system going so we would have a cool area for Christmas dinner, enjoy yours.

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[<ramrod]

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Sir your pressures' look great but I do have problem with your power is this unit 3 phase 415/3/50

Ø or single phase 415/1/50, because if you have power of single phase two wire power supply your system Ø is "not" more then about 3.5 tons or 42,000 btu, and not 6.25 tons. Based on your power consumption of 9 amps. Ø I am not AC person but I am Refrigeration Tech. I am puzzled little with your power info. Normally 440-60 hrz is Ø run on 380-50 hrz but as you said it is manufacture there so?

In Australia 3 phase is 415 volt 50 cycles, (3 wires, unless there is a neutral connected which then it is 4 wires)

Single phase is 240 volt 50 cycles.

I have worked on a few systems that had 3,300 volt 3 phase motors on them but they were huge systems.

3 phase 50 cycle motors run here around 1440 (4 pole) or 2800 RPM (2 pole) compared to motors in the US on 60 cycles running much faster (2 pole 1750 RPM)

The compressor was not made here, the condenser and fan coil unit was made here, they used to make the compressors here here but stopped many years ago, now they are imported, from Scotland I think, Carlyle Compressors). At one stage they were imported from Japan. They could be imported from the USA, but are made for our voltage.

Page 20 shows that a 50 cycle 06DA818 compressor (6.5 hp) is rated at 18.29 Kw (air cooled) or 22.84 Kw water cooled.

18.29 Kw is around 62,408 (around 5.2 tons)

22.84 Kw is around 77,933 (around 6.5 tons)

Note the Kw are cooling capacity, not electrical power.

As my system is running at around 240 PSI head pressure it is much closer to the water cooled details than the air cooled details

240 PSI is around 113 f (45 c) condensing, so I am running somewhat cooler than the 131 f (55 c ) condensing that they are quoting for an air cooled system, also my suction pressure is a little higher, which would increase the capacity a bit, so I am using a number between the water cooled and air cooled to estimate the cooling capacity.

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