air conditioning question

[happyhero]

Hi Hope this question is ok here, I checked the history on here and air conditioning seemed to be on this electric forum most. And I thought an electrician is the most likely tradesman to also fit air conditioning, sorry if I got it wrong.

My Dad moved to Greece a few months back and has got some air conditioning fitted and we are trying to establish what it is he has. I googled the subject but still not sure.

He has a Sharp unit on the wall inside and the unit on the wall outside. The unit on the inside says it is and inverter unit. On reading up this seems to be a unit that is more economical to run and will vary the compressor pump speed rather than stop and start it like a conventional unit. Have I got that bit right?

The guy who serviced it a while back, he thinks told him that it can heat as all inverter types heat, is this so?

I thought ones that heat need a heat pump, or am I wrong here?

I also thought a heat pump is a big square box with fan on top that you usually see on roofs and not the things you usually see on walls which are a smaller unit and have their fan on the side, can you put me right here?

Any info appreciated.

 

[Lectrician]

Yup, they can heat too. Set the temp, and let it cool or heat acordingly.

Dont confuse heat pumps with the air con.

 

[tim west]

Or chillers, proper air conditioning is different, not only is heating and cooling controlled but also humidity

 

[electronicsuk]

Yup, they can heat too. Set the temp, and let it cool or heat acordingly.

Dont confuse heat pumps with the air con.

I'm sorry, but this is just completely wrong. Inverter technology has nothing to do with whether or not an A/C unit is capable of heating, the OP is correct in saying that it is simply a way of varying the compressor speed as the cooling load changes to give greater electrical efficiency.

Generally speaking, manufacturers refer to any A/C unit capable of both heating AND cooling as a heat pump. It seems to be a common misconception that a heat pump has to involve water in some way, but that isn't true. What you're referring to when you think of a heat pump is a ground source unit, where a loop of water is buried in the ground one way or another and pumped through a heat exchanger. Usually, air conditioning is an air to air, or air source, heat pump. The underlying technology is the same, the only real difference being that the indoor and outdoor units both exchange heat directly to the air rather than to a loop of chilled or heated water.

So, again, the OP is right in saying that what he needs is a heat pump. If you want to find out whether or not the unit is capable of heating then can't you just try it? Presumably the remote wont allow you to select heating mode if this function doesn't exist.

 

[happyhero]

Hi thanks for the help, I am actually on holiday with my dad now, his unit we have played with, it has a lot of options but nothing says heat. What it does do is have a temperature setting which we can get to go up to 32degrees but being as the the actual daily temperature here is currently varing around the upper 30's it is hard to prove any heating when turning it up to this temperature. We tried one evening but even set at 32degrees it still seemed to be fairly cool air coming out.

Thanks for your replies but the other thing I can still not understand is this, I used to work in a big building and they had the typical air con units mounted on the outside walls but they also had a roof with cube like units on it which the engineers referred to as heat pumps hence my thinking that air conditioning with heat facility will require a cube like object with fan on top, but are you saying that my Dad could have what appears to be the typical wall mounted unit and yet it could still heat ie it may contain a heat pump within it?

 

[electronicsuk]

Yes, heat pump does not have to equal big rooftop plant, you'll be able to get something pretty much identical to the existing unit capable of heating.

In your experiments with the existing aircon, if you set it to 32 degrees and it isn't capable of heating then it'll simply run the fan and not the compressor. If the ambient temperature is high then many units won't even operate in heating mode, so you won't truly be able to find out until you have a cooler day.

 

[happyhero]

Ok thanks very much electronicsuk for all the help, one last question .... or two, so are most or all modern air con units capable of heating or do you have to selct it especially, ie if I went into B&Q and bought one of their units would it heat as well or would I have to check for the right model?

The reason I ask is I am starting to wonder whether it would be worth getting one for my attic extention in the future instead of fitting a radiator.

 

[Corgigrouch]

Yes, it would be worth while doing that but I wouldn't fit a B&Q unit ... Clue.. Next time you are in B&Q have a look at what they use in their own offices.. There is a reason why they don't use their own "Airforce" stuff.

Have a look at the data plate, cooling only units will only state their cooling capacity, heat pumps will have their heating capacity on the plate also. Heat pumps simply have a reversing valve inside the casing to allow the refrigerant to flow in either direction depending on what the unit is doing, heating or cooling

A loft room will get quite hot i the summer and so you will benefit from th comfort cooling that they provide, but do match the unit to the heat load if you want it to work correctly

 

[happyhero]

So the Airforce stuff is rubbish I take it, could you recommend a couple of good makes that sell at competitive prices, before I leave this post alone.

 

[Corgigrouch]

Yep, the airforce stuff is a bit pants and parts back up is poor too. If you shop round you should find a nice little Hitachi inverter heat pump for around £360+VAT, My suppliers are doing an offer on Panasonic at the mo, their lowest priced unit is a fixed speed (Non Inverter) Heat pump for £199 +VAT. Both come with a 3 year warranty but they have to be professionally installed and serviced.

There are lots of good deal about at the moment due to a poor Summer so it is worth shopping round

Avoid anything that says "Powered by" or just state what make the compressor is as they simply have the big brand compressor with their own electronics and dubious build quality.. Look out for Panasonic / Daikin, York,Toshiba, Hitachi, Sanyo or Mitsubishi Electric/ Mitsubishi Heavy, all good stuff and go for an R410a refrigerant system too