Freezer to fridge

[DocIMC]

Hello all,

I hope that this is the right forum.

I would like to purchase a small chest freezer (new)
and convert it to a refrigerator for use at a remote
camp (solar power only).

I expect that if I add a VT9 thermostat that this
would be sufficient for control and the unit would use far less amp hours than a regular bar fridge?
Suggestions welcomed.
DocIMC

[frank]

What sort of power are you able to generate from the solar panels?

[DocIMC]

Hello,

I am using 3 by 32 watt panels that supply
a 60 Ah battery pack (Nomad 1500 W) with 12V inverter. I am now adding an additional deep cycle battery with 100 Ah rating.

[frank]

So, given all that low voltage gear and assuming you will be getting regular sunshine 12+ hours/day, what amount of 240v amperage will be available, especially at night when the solar panels will be U/S?

[DocIMC]

Hello,

I'm not sure where this is leading...
I was just wondering if I could change the
thermostat to control the freezer at
fridge temperatures.

Thanks

[frank]

A normal domestic refrigerator running off mains voltage will run some 15/18 hours out of 24 depending on door openings. Running currents will be around 1 to 1.5 amps.

Will your solar panels / batteries be able to provide this requirement and cope with the start current? Once you have produce inside the fridge it will need constant power to prevent loss/spoil.

The change of stat will only allow the freezer to operate at a higher temp (fridge) but without sufficient power you will won't be able to operate at all.

[DocIMC]

On first attempt my battery (60 Ah) was able to
operate a small fridge but with one panel there
was not enough solar energy to recharge the battery.
The addition of 2 more panels and the additional
100 Ah battery allow suitable power.
Now as I said, I wonder if a chest freezer converted to fridge with a stat change would draw less current.
Also, the chest freezer would be better suited for opening and closing with less cold air loss.
Do I need to consider anything to do with the
compressor requirements i.e. is the compressor in a freezer the same as that in a fridge?
Thanks

[frank]

On first attempt my battery (60 Ah) was able to
operate a small fridge but with one panel there
was not enough solar energy to recharge the battery.
The addition of 2 more panels and the additional
100 Ah battery allow suitable power.
Now as I said, I wonder if a chest freezer converted to fridge with a stat change would draw less current.
Also, the chest freezer would be better suited for opening and closing with less cold air loss.
Do I need to consider anything to do with the
compressor requirements i.e. is the compressor in a freezer the same as that in a fridge?
Thanks

If you are going to convert the chest freezer to a fridge then it will draw the same current as it's the same piece of kit

The stat change will allow the unit to cycle off at an earlier point (temperature wise) but while it is running it will still draw the compressor plate amps.

You are right about the lesser loss of cold air in a chest 'fridge'

I feel that the energy drawn from the battery will be in excess of the solar energy input and you will end up with flat batteries - mostly because the energy input will be dependant on the sunshine which is not 24 hours but your energy usage will be

[DocIMC]

Frank,

Thanks for the valuable comments.

DocIMC

[Langer]

Id say you're right, because being a freezer, it'll pull temp quicker so cut out on stat quicker, thus saving running cost/power.

Like, if a normal chill cabinet took 2 minutes to go from 4'c to 1'c, your freezer cabinet would do it in less id say.

[Abe]

Hello all,

I hope that this is the right forum.

I would like to purchase a small chest freezer (new)
and convert it to a refrigerator for use at a remote
camp (solar power only).

I expect that if I add a VT9 thermostat that this
would be sufficient for control and the unit would use far less amp hours than a regular bar fridge?
Suggestions welcomed.
DocIMC

Doc

Ive done it loads of times.
Change the thermostat ( your wholesaler will tell you which one to buy)
And your freezer will work as a cooler

Good Luck

[taz24]

The short answer to your question is yes.
The frezzer will work as a fridge but power will be an issue. If you are happy that your supply is sufficient then go for it put the other stat on and give it a try. One problem I can forsee is the comp may overheat because there may not be enough cooling provided by the return gas due to the system cutting out at a higher temp.

Cheers taz.

[Toolman]

OK I read all these posts and your conversion sounds good but if anyone rings me and tells me they want to do this on a larger commercial system, I always tell them we dont do it , it will have problems .
Mainly due to the fact that a low temp system operates at a lower back pressure and has a lower starting amperage . So the compressor being off for quite a long period ( not working so hard for medium temp ) will probably stall on start up .
If it doesnt and has the grunt your in luck .

Ah yes and as Taz says overheat problems if it runs .

[Frosty]

Hi docIMC

Compressors are normally supplied to fit the application i.e a freezer aplication will generally use a compressor suited for low back pressure applications and a high temp application will utilise a compressor suited for high back pressure applications. If you are serious about converting to high temp, you may have to change the compressor (less displacement) and upgrade the condenser to suit the higher operating evaporating pressures.

PS, the length of the capillary tube may have to be adjusted as well.

Regards

Frosty