Building a Mini-Split from a window unit?

[mpire]

Ok, so I have been through the mess of installing a few mini-splits and more recently repairing leaks and sensor issues on my 5 year old LG mini split. I am still very happy with the unit and now that its fixed its going strong.

Now I have plenty of refrigerant, gauges, and the necessary tools to play with this. I am sticking to 410a refrigerant, but only because that's what I have.

So I was thinking about making my own mini split, really just playing around with the idea. I don't really need another AC unit, but my friend lent me a small 115v window unit when the mini split broke and he just told me to keep it.

So... I have a small window air conditioner, and the goal is to split the compressor unit away from the evaporator unit by 6 to 10 feet to see if it works and then to do some testing to see how much power it takes.

From digging around in the AC, the only thing I think I will need to add is an additional fan on the evaporator.

Do you think that it will have much of an effect to extend the lines to the evaporator other than needing a bit more refrigerant?

 

[Big Daddy Chop Shop]

You can certainly do this. If its just to learn and play, go for it. Your challenges will include getting the correct airflow over the evap coil, getting your charge correct, and building a case for the evap. I have toyed with this over the years, but for me the availablity of free or very cheap damaged units has made it a super low priority.

It would be cool to play with for sure and learn, but I would not depend on it for anything.

I would do some cool stuff after getting it going, like do a heat pump by adding a reversing valve, or whatever you like. Just know that it will not have the variable speed compressor needed to be like a modern minisplit.

 

[tyme2par4]

I don't believe window units use 410a, and they may not function if that is what you refill it with.

 

[mpire]

They are putting 410 in everything. Its got a pink sticker saying 410a and POE oil only on the compressor.

 

[Bronson]

That should be doable and without too much effort.
We will need pics, lots of pics!

 

[Big Daddy Chop Shop]

I don't believe window units use 410a, and they may not function if that is what you refill it with.

No units designed for R22 have shipped since Jan 1 2016, and those where dry ship units. R22 is still sold every day. The price is crazy, (around $500 for a 30# jug locally) but its still around, and will be for a while.

 

[mpire]

All the new window units at Lowes have 410a in them.

So I guess its pretty common. I am going to have to add a couple service valves to make this work, but otherwise I shouldn't have to buy anything but copper to extend it. I have everything else I should need.

 

[Fixin'Stuff]

I seem to recall reading that some cheap window shakers used R134a. Has that practice gone by the wayside as 410a has become widely available?

 

[mpire]

I think everything is using 410a now. Even the Hyundais have it.

 

[ssbtech]

I just bought an LG window unit and it has R32 in it.

 

[Big Daddy Chop Shop]

The refrigerant world is a mess right now, possibly more confusing than the initial phase-outs.

Now R134a has a phase out date, and the current administration in the Oval office wants to move it up. Many other refrigerants do as well. You will see a very chaotic and diverse market place for several years, with little to no consistency brand to brand. Many equipment manufacturers are developing their own refrigerants now, Trane made an announcement a few weeks ago, stunning everyone in the Low pressure market. They are currently building a Plant with Dupont to produce this.

They days of carrying one, 2 or even 3-4 refrigerants on a service truck are OVER. Our techs routinely carry R22, 404a, 407c, 134a, 410a, and we go thru drums and drums of R123 and still some R11.

But its going to get worse. And we do not do much actual refrigeration work, mainly a/c.

 

[crabjoe]

Trane made an announcement a few weeks ago, stunning everyone in the Low pressure market. They are currently building a Plant with Dupont to produce this.

What is "this"? I don't see a link or anything...

Thanks!

 

[mpire]

Well, in this particular case I went and looked at all the AC units at Lowes yesterday and every one on the shelf had R410a fill on the label.

 

[ssbtech]

This was the label on my new window A/C. Not very comforting on a home comfort device

 

[Fixin'Stuff]

This was the label on my new window A/C. Not very comforting on a home comfort device

Ouch! What brand is the unit? I've read that propane, butane, etc. do a good job of cooling, but yeah, there is the BOOM possibility.

Is that thing UL listed?

 

[ssbtech]

Ouch! What brand is the unit? I've read that propane, butane, etc. do a good job of cooling, but yeah, there is the BOOM possibility.

Is that thing UL listed?

It's an LG.

R32 is flammable.
http://www.lg.com/us/air-conditioners/lg-LW1216ER

 

[mpire]

Funny. All the LG mini splits use R410a.

 

[mpire]

So I was walking around looking through the holes in some new window units and they have this odd looking squished one from Frigidaire. Looks like the smashed the front down flat, and it uses a separate squirrel cage fan up front instead of the one combo fan between the two. Plus the front and back housings appear to be separate pieces. So I am thinking I might pick one up to look around inside it.

 

[mpire]

 

[Fixin'Stuff]

R32 is flammable.

I found an interesting pdf article about it here: http://www.airah.org.au/imis15_prod/Content_Files/HVACRNation/2013/Nov13/HVAC_Nov13_01.pdf

According to the article, R410A is actually a 50/50 blend of R32 and R125, a fire suppressant.

Also:

“The relationship between GWP and flammability is a trade-off,” says Knox. “Lowering GWP inevitably raises flammability and vice versa. This is unavoidable due to the physical characteristics of chemicals.”

However, with the demand for packaged residential air conditioning in the developing markets of China, India and Brazil now dwarfing that of the developed markets, the step to R32 is now considered necessary.

Not only is R32’s GWP much lower than that of R410A (675 versus 2090), but research has also revealed a host of efficiency benefits. For instance, R32 has a potential refrigerating effect 1.5 times that of R410A, while the pressure losses are lower for the same capacity. Liquid density is also 10 per cent lower, meaning the pipe diameter can be smaller and as a result, the refrigerant charge could be up to 30 per cent less than that of an equivalent R410A system.

Along with its environmental and operational efficiency benefits, R32 also offers a financial incentive with an equivalent carbon price levy of $15.70 per kg versus $41.66 per kg for R410A. (This of course assumes the equivalent carbon price levy on refrigerants remains).

Overall, interesting reading.

 

[danski0224]

So I was thinking about making my own mini split, really just playing around with the idea.

So... I have a small window air conditioner, and the goal is to split the compressor unit away from the evaporator unit by 6 to 10 feet to see if it works and then to do some testing to see how much power it takes.

Do you think that it will have much of an effect to extend the lines to the evaporator other than needing a bit more refrigerant?

The efficiency gains that a mini split offers come from the inverter based compressor and other sophisticated controls.

Your el cheapo window air conditioner has none of that. I suppose it is possible that some tech is trickling into window shakers, but these are typically built to meet a price point.

You are not creating a mini split by moving the evaporator away from the compressor and condenser, sourcing parts from a window shaker. You are simply creating a split system.

Your amp draw will be more if you have to add a fan, the amp draw is printed on the data plate. No need to build it to "check and see".

 

[mpire]

I am aware of the stated power. I want to know how much I use it and I am going to put a power meter on it to determine how much use it gets boosting the cooling in my office.