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View Full Version : PLEASE ADVISE: Re Portable A/C



mordechai
23-04-2007, 10:30 PM
Hi there

We are an old age home trying to purchase a large amount of Portable A/C Units for the private flats n the home.

We have come across a lot of terminology which we have not got a clue about and would be ever so grateful for you experts out there to help us out.

1) In general the flats where the old people live do not need to be cooled down to say 20 degrees (which i understand is what an a/c is supposed to do). 23deg would suffice. How would that then effect the unit size requirement

2)There are units out there with different dehumidification rates. 40 litres a day, 20 litres a day. How impo. is this when choosing the unit.

3)we were looking at an AMCOR 15000 BTU portable unit. It seems there are two types of BTU measurements. ENTHALPY and EU. It seems when the manufacturers state their unit is 12000BTU - it is 12000 BTU ENTHALPY but only 9600BTU EU. What should we be looking for.

Many thanks in advance

racs
24-04-2007, 05:34 AM
You could use this to give you an idea of what you require.
**link removed**
Please feel free to get in touch if you need any other questions answered.

Cool Kev
25-04-2007, 05:50 PM
Hi, You need to consider the sq m area to be cooled and what type of portable; Monoblock = Exhaust Hose; Split Type = Flex Refrigerant Lines & outdoor condensor.

Do not worry to much about dehum figures.

Some manufacturers are ' optimistic' on their cooling capacities, so look for a Eurovent Certification.

Finally you will get better performance and Class A Energy Efficiency with a new model using R410a Refrigerant.

Hope this helps, we supply a lot of portable A/C Units.

Argus
25-04-2007, 07:13 PM
Cool Kev is right.

These small portables are mostly designed and made in the Far East as a temporary cooling solution. In these countries high ambient humidity demands a dehumidification feature. You are unlikely the need it in this country unless you have a serious problem with residual dampness.

The capacity expressed in Btu (an obsolete measure – it should be kW) is the total enthalpy. (12000Btu is about 3.4 kW). As most of these machines are designed with a sensible heating ratio (SHR) of about 70% - 80%, this means that 20% - 30% of the total figure is devoted to dehumidification, rather than useful sensible cooling; in our climate, drying air for human comfort is not an essential feature.

Portable machines are essentially spot coolers. This means that they discharge the heat into the room, whilst cooling the area in front. Some are water cooled and rely on discharging water vapour through an open window or a port through a wall. The water cooled variety will require regular descaling in hard water areas. Additionally they are frequently the least efficient and therefore the most expensive to operate in comparison with an installed system.

Small AC systems below 12kW cooling capacity use the same rating system as fridges and washing machines to denote their efficiency, ‘A’ rating being the highest, ‘G’ the lowest. Most portables will be in the mid range, D or E. In comparison, small split systems are frequently A rated.

In the circumstances you describe I would urge you to consider installed systems. Most are heat pumps and you will get a machine that also heats, is quieter in operation and you can also look around for units with a high degree of electrostatic air filtration if you have residents with dust allergies or breathing difficulties.

As a one-off cooling solution on the hottest days of the year, portables are a great thing to keep as a stand-by – but they are definitely not a serious consideration to a cooling requirement that you describe, in my opinion.

Finally, if you are a UK business, paying corporation tax, you can choose to install split systems that will qualify for enhanced Capital Allowances (ECAs). This will give you all the capital allowance that is written off over 10 years as a one-off tax break in the first year. It equates to about 30% of the capital cost. Needless to say, this applies to certain products that are approved for this purpose and does not apply to portables.