Appreciate some advice in calculating the energy use of a 12 year-old H701 Fisher and Paykel Chest Freezer. It was not possible to run an energy meter, hence I am asking for some help.
The thing does not look pretty. It needs a good defrost...
It runs on 1.68 amps, so presuming that this 400W motor is cycling on 40% of the time it would be using a smidgen under 4kWh per day / approx 1400kWh per year.
I know that refrigeration technology has improved significantly during this time but am not completely confident in the above extrapolation.
Anyway the modern equivalent use 699kWh per year i.e this would be about a $150 a year saving if replaced.
Appreciate your thoughts
Haldane
Energy use of H701 Fisher and Paykel Chest Freezer approx. 12 years old
(7 posts) (5 voices)-
haldane
MemberPosted Thursday 23 Aug 2012 @ 8:43:42 am from IP # -
johnmath
MemberWithout a proper monitor, your estimate is probably reasonable from my experience. The duty cycle is going to vary as the ambient temperature goes up and down over summer and winter, plus adding items to the freezer will also cause it to run longer until the extra heat is extracted.
Refrigeration technology hasn't really changed much over the past several decades. Slowly manufacturers are making minor improvements in insulation and heat pump efficiency, that's all. I recently purchased an Electrolux which is rated at around 315 kWh per year, the best I could find, yet it still has several easily fixable problems that are wasting energy.
Firstly, the compressor and condenser are underneath the fridge which means that a fair amount of the exhaust heat soaks back into the fridge, whence it has to be extracted again! Secondly, there is no fan to assist with the dissipation of exhaust heat which means the heat gradient that the heat pump has to lift over is greater than it needs to be. Thirdly, the cold air circulation fan continues to run when the freezer or fridge door opens, pumping all of the cold air out and replacing it with warm moist air that has to be dehumidified and chilled, and then the condensed moisture freezes onto the evaporator and has to be thawed by the defrost circuit using even more energy!
With my previous "energy efficient" fridge, I was able to reduce energy consumption by 40% with a few simple modifications, and I suspect I will be able to replicate that result again with the new "energy efficient" fridge. For an example of a reasonably efficient chest fridge, have a look at Vestfrost SE325 chest freezer which uses around 300 kWh per year. This is a lot smaller, but doubling the volume should only add about 20% to the energy consumption of a freezer, so the 699 kWh of your "modern equivalent" is still wasting around 50% of the energy it consumes.
Sorry about the rant...
Posted Friday 24 Aug 2012 @ 10:45:06 pm from IP # -
alfresco24
MemberHow did you determine its current is 1.68amps? and, do you know the real voltage range?
I'd be very surprised if the duty cycle is 40% - that's very high for a residential fridge under 'normal' conditions.I have 2 fridges.
The old one 350 litres (35+ years) in the laundry is set warmish to around 9'C and runs at 298 watts for 7 mins every 49 mins. (It has good seals)
The new one 450 litres (<4 years) in the kitchen is set to around 5'C in the fridge and -4'C in the freezer, runs at 210 watts for about 10 mins every 39 mins.
Perhaps this can help you compare stats a bit.
I'd include a graph here but cant paste image.Posted Wednesday 29 Aug 2012 @ 9:34:47 am from IP # -
Being a chest freezer another option is to connect an external thermostat and turn it into a fairly efficient chest type refrigerator.
Posted Wednesday 29 Aug 2012 @ 7:48:55 pm from IP # -
haldane
MemberThanks so much for the responses
Johnmath: This a chest freezer being used commercially - very much agree that chest freezer could be significantly more efficient!
alfresco24: The 1.68 amps is form the manufacturer. I am suggesting the cycle time is high as this unit ain't looking pretty... It is a chest freezer rather than a fridge
Rockabye: They seem great systems - particularly for off-grid situations.Cheers
HaldanePosted Thursday 30 Aug 2012 @ 7:42:52 am from IP # -
Ben1
MemberHeldane, if you have the model number of the freezer, it would be worth a call to F&P to ask if they have the star rating info for that model. A 12 year old freezer would have been rated under an older minimum efficiency performance standard.
Why can't you attach an energy meter to the freezer?
Posted Thursday 30 Aug 2012 @ 8:24:09 pm from IP #
