Capillary expansion. Maximum capacity???

[Chris_]

Hiya guys, long time reader but first time poster so be gentle with me.

I'm an electrician/AC fitter. We do do refrigeration (chilled water AC) but at the moment it's just split install's.

I've been in the trade just coming up 3 years so still got plenty to learn especially on the fridge side of things.

And thats where you guys come in.

As a little bit of a project, i'm using some surplus gear from work that was going in the skip to build a heat pump/AC for a club house. It's mainly for winter heating but thought i might aswell do both.

To keep things simple (read: cheap) i was thinking of using capillary expansion, only problem is, the rig is looking to be about 22Kw. All the simple calc software etc says capillary is only really used upto a max of about 10kw, and i dont know enough about this stuff to know why?

I'm not looking for close control or anything, just a warm breeze in the winter and a cold breeze in the summer.

Do you reckon i'd be able to obtain this with caps?
Can anyone post the calculation formula, or a software calc that goes higher than the danfoss 10kw limit?

Look forward to your responses.

Cheers Guys,
Chris

PS: basic system spec - 22.5Kw, R407c, Cond 45DegsC Evap 10Degsc

[install monkey]

what system are u putting in?

[Chris_]

In what respect?
Room size will be about 50m2

[Chris_]

Doh, was hoping to use a reversing valve with capillary expansion both ways.

[Brian_UK]

How about using more than one capillary tube per circuit?

[install monkey]

the quote-rig is looking to be is about 22kw,what is it? and how are u intending to control it?

[charlie patt]

like brian says multi cap it if it being built with multi cap i would advise a cpr if there one around

[Chris_]

Hiya,

The coils i'm using are both second hand condenser coils, so i was hoping to split them up and effectively run them as several evaps in parallel with multi capillary. How does this effect the sizing? does that mean if i split it into 4 evaps i'll have 4x 5.5kw to play with? Will that work for the capillary sizing?

Control wise i haven't really figured out yet, and i'm open to suggestions.

Was thinking of incorporating hot gas bypass aswell to save short cycling the compressor.

Regarding the 'CPR', cant say i've come across one of these before? Can you explain?

Cheers
Chris

[charlie patt]

limits the pressure back to comp, if you get the caps a bit wrong you can have various sizes and adjust back pressure so you dont kill your comp there adjustable so you can adjust whilst testing crankcase pressure reg