Fridge Power Consumption

[GUMPY]

Looking at fridges as mine needs regassing and it takes R12 which is now illegal.

Shoreline do a RR5010W which is an LEC R5010W fitted with a 12/24v compressor.

The 230v one uses 156kWh/yr the 12v one uses 117kWh/yr.

 

How can the 12/24v one use so little compared to the 230v one.

Note I am not including inverter losses.

Edited August 6, 2013 by Loddon

[by'eck]

I have one of these fridges and can highly recommend it. Now been on continuously for 14 months.

 

The lower annual power consumption of this DC fridge may be down to the performance of the Danfoss compressor.

 

I would also be tempted to think that the power consumption of household AC versions doesn't carry the priority as with DC battery powered ones.

 

Certainly another argument for direct DC powered refrigeration on a boat (as if you needed one)

[GUMPY]

To buck the trend I will be going for the 230v one as we already have the inverter and spend more time on the moorings than out and about and the extra 400 for the 12v one is not something I have.

I was just curious as to why.

[nicknorman]

Looking at fridges as mine needs regassing and it takes R12 which is now illegal.

Shoreline do a RR5010W which is an LEC R5010W fitted with a 12/24v compressor.

The 230v one uses 156kWh/yr the 12v one uses 117kWh/yr.

How can the 12/24v one use so little compared to the 230v one.

Note I am not including inverter losses.

Presumably down to a different type of motor. Does power factor correction increase power consumption on an AC motor? Not sure.

[ditchcrawler]

Looking at fridges as mine needs regassing and it takes R12 which is now illegal.

Shoreline do a RR5010W which is an LEC R5010W fitted with a 12/24v compressor.

The 230v one uses 156kWh/yr the 12v one uses 117kWh/yr.

 

How can the 12/24v one use so little compared to the 230v one.

Note I am not including inverter losses.

Lec use to sell that direct to the public for a lot less than that.

[Dottyshirl]

I relate to this topic and have a question, hy cn I not use this fridge on our narrowboat

 

http://www.amazon.co.uk/Caravan-Motorhome-43Liter-Leisure-Absorption/dp/B00AVZZLT4%3FSubscriptionId%3DAKIAJGH22R74RS37SYSA%26tag%3Dsupapricouk-21%26linkCode%3Dxm2%26camp%3D2025%26creative%3D165953%26creativeASIN%3DB00AVZZLT4#productDetails

 

I will go ans ak the supplier ! lol x but I wondered what your comments were

[nb Innisfree]

Inverter losses apart my guess is that there is little or no difference in efficiency between modern 230v and 12/24v fridges.

[GeoffS]

To buck the trend I will be going for the 230v one as we already have the inverter and spend more time on the moorings than out and about and the extra 400 for the 12v one is not something I have.

I was just curious as to why.

 

 

Inverter losses apart my guess is that there is little or no difference in efficiency between modern 230v and 12/24v fridges.

 

This was my conclusion too a couple of years ago, that the extra cost doesn't justify the potential energy savings and that is without being on any shorepower. However I am not using the boat every day and in the winter normally use the cratch as a cooler.

[GUMPY]

I relate to this topic and have a question, hy cn I not use this fridge on our narrowboat

 

http://www.amazon.co.uk/Caravan-Motorhome-43Liter-Leisure-Absorption/dp/B00AVZZLT4%3FSubscriptionId%3DAKIAJGH22R74RS37SYSA%26tag%3Dsupapricouk-21%26linkCode%3Dxm2%26camp%3D2025%26creative%3D165953%26creativeASIN%3DB00AVZZLT4#productDetails

 

I will go ans ak the supplier ! lol x but I wondered what your comments were

In theory it should work fine.

But and its a big but it will flatten your batteries if used on 12v. The fridge draws about 7.5amps all the time so that's 180Ah in a 24hour period.

Not sure if the gas part will pass the BSS

[ditchcrawler]

Looking at fridges as mine needs regassing and it takes R12 which is now illegal.

Shoreline do a RR5010W which is an LEC R5010W fitted with a 12/24v compressor.

The 230v one uses 156kWh/yr the 12v one uses 117kWh/yr.

 

How can the 12/24v one use so little compared to the 230v one.

Note I am not including inverter losses.

Where did you get the rating for the 12/24 volt fridge from? I have not been able to find it.

I relate to this topic and have a question, hy cn I not use this fridge on our narrowboat

 

http://www.amazon.co.uk/Caravan-Motorhome-43Liter-Leisure-Absorption/dp/B00AVZZLT4%3FSubscriptionId%3DAKIAJGH22R74RS37SYSA%26tag%3Dsupapricouk-21%26linkCode%3Dxm2%26camp%3D2025%26creative%3D165953%26creativeASIN%3DB00AVZZLT4#productDetails

 

I will go ans ak the supplier ! lol x but I wondered what your comments were

I guess it would be this "Whether operating on electric or gas, this fridge is not suitable for use in boats" as stated in the add.

[Dottyshirl]

Thanks guys x

[GUMPY]

Where did you get the rating for the 12/24 volt fridge from? I have not been able to find it.

 

 

From that ever reliable shoreline site!

I have always been dubious about their claims......

In the end we now have a larder fridge 230v 106kWh/year

Thats 24Ah per 24hrs plus inverter losses.

The inverter draws just under 2amps when on so worst case is 50Ah per 24hrs.

 

don't quite know what we will do for ice for the G&T.

[ditchcrawler]

From that ever reliable shoreline site!

I have always been dubious about their claims......

In the end we now have a larder fridge 230v 106kWh/year

Thats 24Ah per 24hrs plus inverter losses.

The inverter draws just under 2amps when on so worst case is 50Ah per 24hrs.

 

don't quite know what we will do for ice for the G&T.

Waeco list their consumption in ah/h here http://www.waeco.com/blaetterkatalog/More_comfort_on_board_2013_en/blaetterkatalog/index.html?lang=en_GB both at 25°C and 35°C Domestic fridges are rated at 35°C

[mrsmelly]

Ive had gas, 12volt 3 times and mains fridges. As a liveaboard i would prefer gas. I have recently sold a 12volt model and bought a mains model. I have looked at the draw of both and whilst running the mains one only draws half an amp including the inverter more than the 12 volt models did. I do have a very good quality inverter so through a cheapo stirling its not so good. for me its a no brainer Ill be staying with mains stuff at about 20 percent of the purchase price and obtainable in any town on any day instantly.

 

Tim

[steelaway]

Ive had gas, 12volt 3 times and mains fridges. As a liveaboard i would prefer gas. I have recently sold a 12volt model and bought a mains model. I have looked at the draw of both and whilst running the mains one only draws half an amp including the inverter more than the 12 volt models did. I do have a very good quality inverter so through a cheapo stirling its not so good. for me its a no brainer Ill be staying with mains stuff at about 20 percent of the purchase price and obtainable in any town on any day instantly.

 

Tim

 

I would agree with all of that - very little difference except for the initial purchase price of the fridge.

 

Alex

[bowten]

I have one of these fridges and can highly recommend it. Now been on continuously for 14 months.

 

The lower annual power consumption of this DC fridge may be down to the performance of the Danfoss compressor.

 

I would also be tempted to think that the power consumption of household AC versions doesn't carry the priority as with DC battery powered ones.

 

Certainly another argument for direct DC powered refrigeration on a boat (as if you needed one)

Well you had a good try.............again!If you already have an inverter go for the 240v,I have always said it.

[Keeping Up]

Surprisingly I've found that our 12v Shoreline fridge takes LESS average power than the figure quoted on the Shoreline site

[Justme]

Surprisingly I've found that our 12v Shoreline fridge takes LESS average power than the figure quoted on the Shoreline site

 

 

As does my mains larder fridge & chest freezer. Roughly about 25% less than quoted over the year.

[smileypete]

Looking at fridges as mine needs regassing and it takes R12 which is now illegal.

Shoreline do a RR5010W which is an LEC R5010W fitted with a 12/24v compressor.

The 230v one uses 156kWh/yr the 12v one uses 117kWh/yr.

 

How can the 12/24v one use so little compared to the 230v one.

Note I am not including inverter losses.

Must be old to be R12 but if it's in decent nick they can be regassed with a 'drop in' equivalent refrigerant.

 

That said it's very unlikely to lose gas unless from physical/vibration/corrosion damage, other problems can give the same symptom.

 

The DC fridges are more efficient because the compressor has a permanent magnet, but nowadays the mains fridges use a slightly better refrigerant so the gap is not so big as it would be otherwise.

 

cheers, Pete.

~smpt~

[George94]

Must be old to be R12 but if it's in decent nick they can be regassed with a 'drop in' equivalent refrigerant.

 

That said it's very unlikely to lose gas unless from physical/vibration/corrosion damage, other problems can give the same symptom.

 

The DC fridges are more efficient because the compressor has a permanent magnet, but nowadays the mains fridges use a slightly better refrigerant so the gap is not so big as it would be otherwise.

 

cheers, Pete.

~smpt~

 

I am sure you are right (you usually are!), but why would a mains fridge use a different refrigerant?

[smileypete]

 

I am sure you are right (you usually are!), but why would a mains fridge use a different refrigerant?

Mains fridges and freezers these days most always use R600a which is iso-butane, basically butane gas! Though flammable of course, it has zero global warming potential.

 

The 12V fridges usually use R134a which is due to be phased out because of it's relatively high global warming potential.

 

Though R600a boils at a higher temp than R134a, it has a higher specific heat capacity as a liquid, so supposedly it comes out about 10% ahead efficiency wise, according to this paper:

 

http://www.duracool.com/PWR_ENG/WHY_HYDROCARBONS_SAVE_ENERGY.pdf

 

Another thing about R600a systems is they can tolerate high ambient temperatures better than R134a.

 

If you ask over on http://www.refrigeration-engineer.com they are the real experts.

 

cheers, Pete.

~smpt~

Edited August 10, 2013 by smileypete

[ditchcrawler]

 

 

If you ask over on http://www.refrigeration-engineer.com they are the real experts.

 

cheers, Pete.

~smpt~

When I asked questions about improving efficiency by condenser cooling I got all sorts of replies

[George94]

Mains fridges and freezers these days most always use R600a which is iso-butane, basically butane gas! Though flammable of course, it has zero global warming potential.

 

The 12V fridges usually use R134a which is due to be phased out because of it's relatively high global warming potential.

 

Though R600a boils at a higher temp than R134a, it has a higher specific heat capacity as a liquid, so supposedly it comes out about 10% ahead efficiency wise, according to this paper:

 

http://www.duracool.com/PWR_ENG/WHY_HYDROCARBONS_SAVE_ENERGY.pdf

 

Another thing about R600a systems is they can tolerate high ambient temperatures better than R134a.

 

If you ask over on http://www.refrigeration-engineer.com they are the real experts.

 

cheers, Pete.

~smpt~

OK. Thanks. So we can expect DC fridges to pull ahead again in future, thanks to their more efficient motors.

[tangledfooted]

I don't know if this helps but I've converted an upright freezer into a fridge. Freezers have much more insulation than a fridge and although this one is side opening because it has drawers not all the cold rushes out when the door is opened.

 

I bought an AEG under counter freezer A rated with three drawers nearly new on eBay for £110 and a digital fridge thermostat for £15 again from eBay. Swapping the thermostats was dead simply just three wires. Works splendidly as a larder fridge and because I've sighted the temperature prop half way down the back of the cabinet rather than at the top - the top drawer acts as a freezer - I can make ice! Sooo nice come 6pm.

 

We've been running it on some pretty knackered batteries (300 odd Ah) and 500w of solar and a 2kVMastervolt inverter and havn't had to run the genie since the solar panels went in in May.

 

I've set the thermostat to start up the compressor at 5 degrees C and shut down at 2 degrees. It automatically defrosts at night for 4 hours. I don't know what the consumption is yet as I don't have anything to measure it with but Ill get round to that soon.

 

The only downside is you have to lay bottles sideways - which led to some spilled milk early on - but weve worked round that now by buying milk in a cartons with the little screw top lid. I keep the gin and tonic water in the top drawer so even if it hasn't iced up I can still get serious come 6 o'clock in a civilized manner.

 

And when you think how much those drawer fridges cost this is quite an elegant alternative - saves my lumber vertebrae as well.

[ditchcrawler]

I don't know if this helps but I've converted an upright freezer into a fridge. Freezers have much more insulation than a fridge and although this one is side opening because it has drawers not all the cold rushes out when the door is opened.

 

I bought an AEG under counter freezer A rated with three drawers nearly new on eBay for £110 and a digital fridge thermostat for £15 again from eBay. Swapping the thermostats was dead simply just three wires. Works splendidly as a larder fridge and because I've sighted the temperature prop half way down the back of the cabinet rather than at the top - the top drawer acts as a freezer - I can make ice! Sooo nice come 6pm.

 

We've been running it on some pretty knackered batteries (300 odd Ah) and 500w of solar and a 2kVMastervolt inverter and havn't had to run the genie since the solar panels went in in May.

 

I've set the thermostat to start up the compressor at 5 degrees C and shut down at 2 degrees. It automatically defrosts at night for 4 hours. I don't know what the consumption is yet as I don't have anything to measure it with but Ill get round to that soon.

 

The only downside is you have to lay bottles sideways - which led to some spilled milk early on - but weve worked round that now by buying milk in a cartons with the little screw top lid. I keep the gin and tonic water in the top drawer so even if it hasn't iced up I can still get serious come 6 o'clock in a civilized manner.

 

And when you think how much those drawer fridges cost this is quite an elegant alternative - saves my lumber vertebrae as well.

There are several articles about using freezers as fridges for this very reason