Project "Home made Heatpump/Ac"

[Pandrone]

Hi.

I and my father are planing to build an Ac/heatpump. And that means alot of questions :P.

We are going to use 404a in it. We also have all the tools needed to get it working ( i think )

What evaporatingtemp does an a/c usually have?

I'll post some pics of the stuff we are going to use, and with it some questions.

Btw, building this partly because my father wants one and because i'm going to study/read refrigeration after i'm done with the "gymnasium" (electrics).

Sorry for my english.

Tomi

[Pandrone]

There's the stuff we are going to use.

The outdoor unit appears to be hotgasdefrosted through the 4way valve (am i right?) damn, the pics doesnt show the piping . Well well, i'll get better pics later.

A pic of the 4wayvalve:



The 4way valve has two electrical connections so i believe it's controlled by the thermostat (right or wrong?). Btw, this system didn't have any thermostat, what should i look for if buying a new one?



The thing marked "1", is that a metering device? ( i believe i have read it's called flottör in swedish, dunno english name)

[Peter_1]

You will have a lot of work to do.

The 4- way valve is there because it's a heatpump.
Where is the fan?

What is for Christ sake the HE exchanger/sightglass and huge dryer combination? Was this also a part from the AC unit?

Seems they had leaks around the lower connections of the 4way valve or it was initialy bad soldered in the factory.

1 can be a metering device but I bet more on a strainer/mesh filter.
You will need to redo the whole wiring.

You can use whatever thermostat you wish but there has more to be done then only switching on the 4 way valve with the thermostat.

I should first check the state of the compressor if this is OK.
Seems they left the system open.
Use the gas that was originally in the system.
Why will you use R404a?

Install a HP and LP safety device, a new dryer and remove all the old ones.

Install a timer so that the unit doesn't cycle to much.

Install a speed regulator on the outdoor fan.

Hope you got it for free because these days, they sell these units brand new for +/- 500 € (5 kW/heat pump), inclusive gass, copper and electrical lines and wall bracket.

So think first once again before you start.

[Pandrone]

Hi.

I got all the stuff for free, and i have acess to more stuff if i want. The drier, sightglass and hp/lp pressostats is from another unit.

And the main purpose of building it is the experience .


I will use R404a just because it's the only gas i have acess too (R290 too but i don't want to use it). I will change the oil in the compressor so that won't be a problem i guess?

I'll test the compressor when i get my hands on a run cap.

And i'll have to get a fan for it too, maybe a car a/c fan would work?

[chemi-cool]

Hi Pandrone

Not everything you get for free worth playing with.

There are many better ways to learn, but......... After you learn, work and gain experiance, then you can start playing.

No, you can not use car AC fan cause it runs on DC 12 or 24 volts.

Chemi

[Snowman123]

R404a for a/c, on water chiller it runs about 5 bar suction, 17 bar Discharge. You will need to change the oil in the compressor too. Easy way is to use R22 or R407c. i would go for R22 run it at 4 bar or 60 psi.

[Pandrone]

Nothing is impossible (well almost nothing.) If i'd use a 12v fan i would use a psu from a pc or something. I might point out that i can braze (or i am learning bit by bit) My father is a welder so he's teaching me. And i have a waterchiller for a pc that's in semi_working condition, so i know what it takes to get this thing running (alot of work). To get to the point, this project is becoming reality.

R404a for a/c, on water chiller it runs about 5 bar suction, 17 bar Discharge. You will need to change the oil in the compressor too. Easy way is to use R22 or R407c. i would go for R22 run it at 4 bar or 60 psi.

I would use R22 or R407c if i had acess to them, but i don't. Can't buy refrigerants in sweden without a company/license. And i'm going to drain the oil no matter what, so just charge it with POE this time .

[Brian_UK]

Hey Tomi

Looks like you are going to have a great deal of fun trying to get that lot working.

The drier, sightglass and heat exchanger from another unit. Throw those bits away, they are of no use to you in AC usage.

It looks like your base condensing unit is a Mitsubishi but I could be wrong.

As Peter said the poor quality brazing around the 4way valve indicates a repair in the past which may or may not have been succesful. The internal surfaces of the 4way valve have teflon/ptfe coatings and are damaged by overheating, so beware.

Yes, you could use a 12vdc car fan but be advised that the increase in noise levels and low airflow will cause you problems.

If you can get the proper fans then so much the better.

Good luck and keep us posted we are all in amazement at your proposal

[gary davies]

is this scandi geezer avin a laugh? although it looks like an installation of mine come to think of it...

[Brian_UK]

is this scandi geezer avin a laugh? although it looks like an installation of mine come to think of it...

Is that one of those "Here's one I made earlier.." moments like all the good cooking shows ??

[Andy]

Hi Pandrone
not to put a damper on things, but you are working with compressed gas and electricity. The reason you can't get the gas is it is un-safe to give it to you without the proper training. I would advise that you get the proper training before you atempt this venture.
Please be careful, I am not saying this to stop you woring at refrigeration, but we have enough cowboys/untrained working in our trade without encouraging any more.

Kind Regards and best intentions Andy

[Pandrone]

Hi Pandrone
not to put a damper on things, but you are working with compressed gas and electricity. The reason you can't get the gas is it is un-safe to give it to you without the proper training. I would advise that you get the proper training before you atempt this venture.
Please be careful, I am not saying this to stop you woring at refrigeration, but we have enough cowboys/untrained working in our trade without encouraging any more.

Kind Regards and best intentions Andy

Hi Andy, i know i'm working with compressed gas, me and my father bought a 10kg bottle of 404a just to get this project (and my projects) going, and i know as much as i should know about electricity (i'm starting year two of three in electricity in a swedish gymnasium). I'm familiar with propane (gasol in sweden) have fillled up three systems already with it, not calibrated or something like that, but hey the systems got frosty on the evap atleast . I'm updating this thread as we start building it, soon that is, just have to get hold of a 40uf run cap .

Btw, the refrigerants, the main thing about not selling it to persons that's not trained is that they "may" make money on it, or may release a bit 134a to the air, not that it will make any damage( we have those air-horns that works on 134a). And ofcourse what you say too Andy

Sorry for my english, not that good huh? .

/Tomi