Fridge types (1 Viewer)

[f6c]

Can anyone explain the difference between obsorber and compressor fridges. Advantages and disadvantages. Thank you in advance

 

[Guigsy]

Compressor fridges are far more efficient, but only run on electricity. Same as a home fridge, including the (hopefully quiet) compressor humming. They still need a fair amount of juice, but with enough solar panels and batteries, you can run a compressor fridge off-grid.

Adsorption fridges work on gas... but most of them also "3-way", so have the option to use 12v or 240v too. But for size reasons, the method they use for electrical cooling sucks down a lot of power. You'd struggle to run a 3-way fridge from battery... but then it doesn't use much gas.

 

[f6c]

Thankyou very much Guigsp

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[two]

Compressor fridges run off electricity only, like the one you’re most likely to have at home. The electricity powers a motor which compresses the gas into a liquid, which then evaporates to cool the inside.

Absorption fridges use a heat source to drive the process, so is able to operate using gas or electricity.

Absorption fridges are silent, whereas compressor fridges may be heard when running. Absorption fridges may be less efficient to run but I don’t think the difference is significant. Absorption fridges are susceptible to slopes, whereas compressors are not. I’d expect absorption fridges to survive the bumps, shakes and jolts of travelling better than a compressor, as they have no moving parts.

 

[f6c]

Thankyou two

 

[nicholsong]

If MH converters fit compressor fridges as new are they not limiting their customer base to those who only use campsites.

We only do do aires and wildcamping, and have even ditched the EHU cable, so would never by a MH with a compressor fridge.

Geoff

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[two]

Not necessarily. Solar might compensate and, maybe, a second battery.
Some 12V compressor fridges are reasonably frugal.
The initial start-up requires more 'grunt', so I assume that models for use where there is limited battery capacity may have a deliberately extended cycle.

 

[nicholsong]

Not necessarily. Solar might compensate and, maybe, a second battery.
Some 12V compressor fridges are reasonably frugal.
The initial start-up requires more 'grunt', so I assume that models for use where there is limited battery capacity may have a deliberately extended cycle.

I would not buy a MH which had to rely on solar for its fridge and all other electrics in winter in N. Europe.

 

[two]

My thoughts are that the fridge will be working hardest in the Summer when, hopefully, there'd be more sun.

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[JJ]

When it is winter you could always put your cold stuff in a tin box thingy outside... like they did in the old days.

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JJ

 

[buttons]

Hi and Welcome.....

 

[Minxy]

I would not buy a MH which had to rely on solar for its fridge and all other electrics in winter in N. Europe.

Unfortunately most PVC converters are fitting them so if that's what vehicle type you want your choice would be very limited. We have a Thetford T1090 mark 2 compressor fridge (the mark 1 version is cr@p IMV) and it does draw quite a bit of power, usually coming on for up to 15 mins every hour. We wild camp for long periods and in summer it's not a problem as we have 200w solar and usually plenty of sun to keep our twin 78ah gel batteries (and cab) nicely charged up, however over winter in southern Spain we got too low for comfort at times. We've been looking at various ways to improve this and after weighing everything up we've bought a genny to supplement/charge up as required - we have chosen this method as it gives us the ability to use some electric gizmos if we want to (Remoska etc). I'd rather have a 3-way fridge but for the PVC we wanted it wasn't an option.

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[Robmac]

I can only go by my own experience, we have a Vitrifrigo 60 litre compressor fridge.

I haven't fitted my solar panels yet so we rely on battery power. We have 2 x Trojan T125's giving 240AH. We can run the fridge for 3-4 days with no problems before having to drive the van to recharge the batteries. The fridge isn't using power all of the time as it is on a thermostat so kicks in when required.

There is a small amount of noise when it kicks in but we haven't found this to be disturbing.

I am thinking of fitting an inline switch so I can turn the fridge off overnight in winter as we don't use heating whilst sleeping and this would conserve more energy.

All in all, I find the Vitrifrigo to be an excellent fridge and we are very pleased with it.

 

[Minxy]

I can only go by my own experience, we have a Vitrifrigo 60 litre compressor fridge.

I am thinking of fitting an inline switch so I can turn the fridge off overnight in winter as we don't use heating whilst sleeping and this would conserve more energy.

All in all, I find the Vitrifrigo to be an excellent fridge and we are very pleased with it.

I think I'm right in staying that the Vitrifigo ones are the 'best' compressor ones out there for low power consumption and performance generally, but are you saying you can't turn it off on the panel on a night? Surely it has an on/off switch?

 

[Robmac]

I think I'm right in staying that the Vitrifigo ones are the 'best' compressor ones out there for low power consumption and performance generally, but are you saying you can't turn it off on the panel on a night? Surely it has an on/off switch?

It can be switched off on the thermostat which is in the bottom of the fridge.

Me being lazy though, I like the idea of being able to switch it on/off from the comfort of my bed so will position the switch accordingly.

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[Guigsy]

We have 2 x Trojan T125's giving 240AH. We can run the fridge for 3-4 days

As a very rough estimate, you need about 50w of solar to sustainably support the fridge on sunny summer days... And lots more than that when it's cloudy and off season.

 

[Robmac]

As a very rough estimate, you need about 50w of solar to sustainably support the fridge on sunny summer days... And lots more than that when it's cloudy and off season.

Without wishing to dispute your figures, we are getting 3-4 days without any solar.

Are you are saying that is what we would need to carry on indefinitely? We have 2x100w panels to fit via a Ring charge controller.

Also, I believe the T125's being 6v they will charge more quickly? (as you can tell, I am no expert on electronics).

 

[Guigsy]

Mmmm. Rather than guesstimates, I'll actually look up some figures...

According to the manufacturer, the Vitrifrigo C60i uses 0.32kW/24h... I assume they mean 0.32kWh per day? Battery charge cycles are about 85% efficient, and manufacturer claims always assume ridiculous best cases, so lets assume you actually open the door a few times and you live in the real world, so you need ~0.5kWh per day from the solar system to keep the fridge going.

As a sanity check, 0.5kWh is about 42Ah (500vAh / 12v) . .. but remember you probably only get half the rated capacity of your battery if you don't want to deeply discharge it. So that roughly tallies with your 3-4 days claim, assuming you don't use much power on anything else.

As a rough rule of thumb, to work out your daily energy income on a sunny summer day, you take the rated output of the solar panel and assume it manages that for an average of 4 hours per day. 500Wh / 4 hours = ~120w

So yes, 200w of panels will easily keep you going through the summer. Winter sunshine is considerably weaker though... when we have any at all. It'll probably stretch out to needing to charge about once per week???

... and if anyone spots the errors in my calcs, please correct me!

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[Robmac]

Mmmm. Rather than guesstimates, I'll actually look up some figures...

According to the manufacturer, the Vitrifrigo C60i uses 0.32kW/24h... I assume they mean 0.32kWh per day? Battery charge cycles are about 85% efficient, and manufacturer claims always assume ridiculous best cases, so lets assume you actually open the door a few times and you live in the real world, so you need ~0.5kWh per day from the solar system to keep the fridge going.

As a sanity check, 0.5kWh is about 42Ah (500vAh / 12v) . .. but remember you probably only get half the rated capacity of your battery if you don't want to deeply discharge it. So that roughly tallies with your 3-4 days claim, assuming you don't use much power on anything else.

As a rough rule of thumb, to work out your daily energy income on a sunny summer day, you take the rated output of the solar panel and assume it manages that for an average of 4 hours per day. 500Wh / 4 hours = ~120w

So yes, 200w of panels will easily keep you going through the summer. Winter sunshine is considerably weaker though... when we have any at all. It'll probably stretch out to needing to charge about once per week???

... and if anyone spots the errors in my calcs, please correct me!

Thanks for putting the effort in.

We do not use a lot of electricity on other stuff at the moment, usually just the lights which are all LED's and so don't use a lot of power.

This will change though as I am in the middle of installing blown air heating which will make quite some difference. We rarely stay put more than a couple of days though so the batteries get refreshed when we drive on, also, Julie prefers sites when we are away so we will be on EHU for much of the time so hopefully we've got it covered.

Thanks again.

 

[MyrtleGuru]

Unfortunately most PVC converters are fitting them so if that's what vehicle type you want your choice would be very limited. We have a Thetford T1090 mark 2 compressor fridge (the mark 1 version is cr@p IMV) and it does draw quite a bit of power, usually coming on for up to 15 mins every hour. We wild camp for long periods and in summer it's not a problem as we have 200w solar and usually plenty of sun to keep our twin 78ah gel batteries (and cab) nicely charged up, however over winter in southern Spain we got too low for comfort at times. We've been looking at various ways to improve this and after weighing everything up we've bought a genny to supplement/charge up as required - we have chosen this method as it gives us the ability to use some electric gizmos if we want to (Remoska etc). I'd rather have a 3-way fridge but for the PVC we wanted it wasn't an option.

Sounds like a retrograde step fitting those to PVCs. The 3-way type gives you ultimate flexibility for four-season, off-grid use.

I can only see the point if you are aiming for a gas-free van with diesel heating, hot water and hob. That would need big batteries and lots of solar, but would be good for Africa, for example.

 

[jongood]

The problem with fitting an absorption fridge to a pvc is finding somewhere to put the vents so they're not covered when the door opens.

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[Minxy]

The problem with fitting an absorption fridge to a pvc is finding somewhere to put the vents so they're not covered when the door opens.

Yes and no ... we used to worry about the door covering the vents when we had a 3-way fridge however there was still quite a gap so it didn't prevent hot air escaping and cooler air getting in, however it was actually a bonus because we used to put that side of the camper facing the sun and the door actually shielded the vents and outside of the camper from the sun giving it more 'insulation' from the heat.