Cool Capacity (Btu/hr) vs Actual Size (ton)

As you stated, 12,000 Btu/h = 1 ton of refrigeration; 45,000 Btu/h = 3.75 tons.

(There may be a higher precision number such as ~12,050; but 12,000 is most commonly used.)

Thanks tornado for the reply, its a confirmation I really needed cos of the confusing spec on the a/c.

Would you also know the conversion rate from the input to ton?

the input on the a/c is 4,500w.

once again thank you.

Hi Lyn,

This is really revealing for me and got me learned.

Now I know why the cooling capacity is in tons.

Thanks

Seun

The watts needed to produce x tons of refrigeration depends on the evaporation and condensing pressures, the refrigerant, the ambient temperature, and the efficiency of the system components. Larger surface area of heat exchangers yields higher efficiencies. For air conditioning, too large an evaporator leads to too high humidity, so a main determinant of system efficiency is the condenser area. Your 4500 watt (electrical input) unit should be easily capable of producing 45,000 Btu/h of cooling, unless the ambient temperature is really hot.

Tornado,

Thanks for your wealth of info.

Am in Africa and the temperature we are experiencing in the last one month has been very high sometimes its just 43degree perpetually.

Am beginning to understand why the a/c may not be achieving the kind of cooling, i really need-ambient temperature is very hot.

Thanks alot

Seun

As Tornado was saying, the capacity is function of evaporating and condensing pressure. The same unit, accepting that outside temperature remain constant, has different capacities at different evaporating pressures. Depending of refrigerant, the capacity the unit has when evaporating pressure is tuned up for +5 deg. C is almost double then when is tuned up for -10 deg C. You can increase the capacity by raising the evaporating pressure (if it has expansion valve you can tune it up), however the power absorbed by the compressor will increase too. Another way to increase the capacity is to lower the condensing pressure, and that can be done by spraying water over the condenser (careful with electric motors) . That helps a lot the unit, mainly in the hottest part of the day.Standard ton is with evaporating pressure for 5 deg. F and condensing pressure for 86 deg. F.

Hi Jerybaciu,

Am interested in the expansion valve tuning. I tried opening it up all I see are gas pipes and some panel.

Could you write how it look?

The expansion valve you find it on the evaporator, (that in inside the house) at the end of the smaller pipe that comes from outside unit. If you see something resembling the picture, then that is it. Do not worry if you do not see it, in this days they make the units much cheaper, replacing it whit capillary tube, that is a very thin pipe. In the last case, you can not adjust the pressure in good way. You need specialised tools (gauges, hoses) to adjust the pressure, and is done (after you hook up the gouges, so you know what you are doing) by opening the cap (that in picture above is in the left side near the bulb (silver), the bulb is attached to the bigger pipe that comes out) and turn the screw clockwise to lower the evaporating pressure, or the other way to increase it. You have to put a amp meter on the compressor to, as the power drown by it will increase. Be careful, the amps have to be lower then that at which the compressor is rated.

This unit has an electronic expansion valve.

Can you give the specific model number and manufacutre?

Johnsonr1,

Thanks for asking.

The model no on the indoor unit is cu-45ffh while the model no on the outdoor is cs-c45ffh and its panasonic.

I tried checking it out on their page , apparently it appeared that they have not updated their site.

Thanks once again

Seun

12000 btu/hr = 1 TOR .Refrigeration capacity is evaporator capacity. Air cooled condensers are 25% higher than evaporator capacity . Heat rejection ratio.

You can help just a little with a very fine occasional water mist on the condensor and by keeping the condensor in the shade if it's very hot.....

Thanks Lucke,

From your analysis and the notes have checked too, the a/c is definitely 38,000Btu/h against the 45,000Btu/h pasted on it.

Figured I had been short changed. But now am very knowledgeable about this.

Thanks

Seun