Dishwashers Off Grid.

nigtomdaw · March 2008

Question about dishwashers.

I have a 3.3 kw rated SW3024E. I have the nice problem of more solar than im using every day the sun shines hitting float around 1pm on sunny days now. Our only luxury is our American fridge freezer 24/7.

To soak up some solar I would like to add a dish washing machine, however trolling the internet for some energy figures all I seem to find is the kw/h rating which for the best energy effieicent machines is 1.05kw/h per cycle.

Limited with 3.3 kw of power I accept that I may have to switch the refer off for a hour whilst I run the dishwasher as this can surge to 2000w for a minutue or so if the defrost cycle kicks in. without warning leaving leaving only 1300 watts for other loads. The problem I have is I have been unable to find out the typical peak wattage hence amp draw of any dishwashers. I can also feed in hot water froma LPG boiler but the peak load when the internal heater element kicks in is going to be the killer.

The wife has got fed up of washing and ironing anything she can when the sun is shining the option of replacing the Inverter is not going to happen.and the euro spec SW 3024E can not be paralelled up.

Taking euro 230v vs US 110v the wattages should be similar. Help please !

autoxsteve · March 2008

Re: Dishwashers Off Grid.

Couple that might help you out are the smaller models. From the US Government Energy star website, the Fisher & Paykel DS605 and Kenmore 1332 are energy misers. Of course, the volume to store dishes is smaller too.

You are correct, electrical load (max) specs do not appear to be published. I'd recommend you visit some stores and look at the id tags on these models to get the peak current (it might be there)....

BB. · March 2008

Re: Dishwashers Off Grid.

Some of them have economy modes of some sort where they don't use the electric heater to get "hotter" water or to dry the dishes faster... That can save on overall power use--may or may not reduce peak power used...

-Bill

Telco · March 2008

Re: Dishwashers Off Grid.

What about something along the lines of one of these devices? Either this, or perhaps a capacitor arrangement that will provide the current surge to start the motor, that will recharge quickly after the motor starts without recharging instantly?

Might also see if you can find a 220V version of a Greenplug to lower usage. I've got a couple of these, but I don't know the actual affect of it on power usage. Seems like they dropped my bill a bit when I first got them. Seeing as I have a Killawatt now, I can find out for sure if they actually cut usage. My deep freeze is plugged into the Killawatt now, I can pull off the greenplug and see what the difference is.

nigtomdaw · March 2008

Re: Dishwashers Off Grid.

The problem will be when the resistive heat load kicks in to bring the water up to the correct temperature, I dont imagine the pump or electronics being used will cause any problems but if the heater element is 2000/3000w then I may have problems !

crewzer · March 2008

Re: Dishwashers Off Grid.

Bill's of course right about the "economy" mode, but it has its pros and cons. A key pro is that the drying mode is turned off and the dishes are air dried.

A con is that typical DW detergent requires a nominal water temp of 140 F (60 C) to function properly. So, your main water heater needs to be set to 140 F, or ya gotta use the DW's internal water heater to bring the wash water up to temp.

HTH,
Jim / crewzer

nigtomdaw · March 2008

Re: Dishwashers Off Grid.

Creewer, I agree there are even some models which have a lower temp setting, probably with some special detergent dw tab, but sods law says if that heater element still might kick in it will. I may be left as suggested and take a look at some name plates in store, maybe download some pdf manuals

Telco · March 2008

Re: Dishwashers Off Grid.

Sorry, guess I misread where you were discussing a possible surge when the fridge defrost kicks in with the dishwasher running. Never mind.

mike95490 · March 2008

Re: Dishwashers Off Grid.

You could always disconnect the heater, or place a manual switch on it.
The problem is if the DW starts the motor & the 900W heater at the same time.

Or you could wire the heater only, to a Mod-Sine inverter (1KW=$99), and only switch that on when needed.
http://www.crutchfield.com/S-E3MkAlZJUbY/App/Product/Item/Main.aspx?I=539XP1000&srccode=cii_17177931&cpncode=08-12577659

westbranch · March 2008

Re: Dishwashers Off Grid.

OK guys here are some real time numbers for a Bosch SMU 2045 6c/14 dishwasher. plugged in the K-A-W last night to see what would come out...the rating stamped into the body is 1.4 Kwh...

boy was I surprised with the result....

.21 Kwh

for a normal cycle, the 1.4 must be for the pots and pan cycle. (we've never used it). this is a 120v model and the max draw was 190 watts. Water temp on the nat gas heater is set at 130 F...

hth

Eric

nigtomdaw · March 2008

Re: Dishwashers Off Grid.

Eric that was just the sort of stuff I was looking for, most of the latest units on sale in Europe with a AAA energy rating, are listed at 1.05 kw per wash cycle. Thanks for making the effort.8)

Nigel

BB. · March 2008

Re: Dishwashers Off Grid.

Check the Energy Guide tags (yellow tags in the US/Canada) closely. It is based on a set number of cycles per year... From the ES website:

On August 29, 2003, the Department of Energy changed the dishwasher test procedure . Manufacturers have until February 25, 2004 to transition to the new test procedure. As part of this standards change, the Department of Energy changed the estimate of the number of times that a dishwasher is run per year from 264 times to 215 times. Since this number is 49 fewer times per year, the annual kilowatt hours (kWh) used per year have decreased for all models. View the Federal Register entry regarding the test procedure for dishwashers (10 CFR Part 430).

Consumers should be aware that models will still be available with the old EnergyGuide label. For models tested with the new procedure, the estimated kWh/year on the old EnergyGuide label will be approximately 20% higher than the estimated kWh/year on the new EnergyGuide label.

This change in the dishwasher standard does not affect which models qualify for ENERGY STAR; since the kWh/year changed for all models, any model number listed here is qualified even if its EnergyGuide label has a higher kWh/year.

Hmmm... Take a look at the 17 page dishwasher testing specification (PDF)... I am sure it make sense--but it is a bit murky... Believe it or not, this sentence is on page 17 of this document:

Thus, this document amends the Customs regulations to reflect that the emergency import restrictions currently in place continue, without interruption, for 3 years from September 4, 2003. T.D. 99–35 contains the Designated List describing the Byzantine ecclesiastical and ritual ethnological material from Cyprus to which the restrictions apply.

-Bill

Brock · March 2008

Re: Dishwashers Off Grid.

Our last one used .22kw per cycle with the heated dry turned off and hi-temp washing turned off. It pulled a max of 1100w during the cycle, but again total laod was .22kw.

nigtomdaw · March 2008

Re: Dishwashers Off Grid.

Agian Brock thanks good info 8)

Dishwashers Off Grid.

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