Go Back   EcoModder Forum > AltModding > Saving@Home
Register Now
 Register Now
 


Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 10-28-2008, 11:12 PM   #1 (permalink)
EcoMod Wannabe
 
Sean T.'s Avatar
 
Join Date: Apr 2008
Location: Lake Orion, MI
Posts: 448

Taurusaurus Rex - '97 Ford Taurus GL (Sedan)
90 day: 19.39 mpg (US)

Blue Wagon - '00 Ford Taurus Wagon SE Comfort
90 day: 19.61 mpg (US)
Thanks: 6
Thanked 18 Times in 11 Posts
Mass quantities of food in the fridge...

I'm sure you have all read that an empty fridge runs efficient because there is nothing that it needs to cool.

Also, a full fridge runs efficient because the cold food holds the temperature.

Well... we have started shopping at one of those discount warehouse stores. That means we have a ton of water bottles, juice cans, etc.

In theory, wouldn't it be the most efficient to load a few items at a time, so the fridge doesn't need to work too hard? And then try to fit all of the food in the fridge so it holds the cold temperature easier and again, the fridge doesn't need to work too hard?

__________________
  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 10-29-2008, 01:33 AM   #2 (permalink)
Dartmouth 2010
 
SVOboy's Avatar
 
Join Date: Nov 2007
Location: Hanover, NH
Posts: 6,447

Vegan Powa! - '91 Honda CRX DX
Team Honda
90 day: 66.52 mpg (US)
Thanks: 92
Thanked 122 Times in 90 Posts
Send a message via AIM to SVOboy Send a message via MSN to SVOboy Send a message via Yahoo to SVOboy
You could just throw some bottles of water in there when you empty it out to balance things out.
  Reply With Quote
Old 10-29-2008, 01:34 AM   #3 (permalink)
Depends on the Day
 
RH77's Avatar
 
Join Date: Nov 2007
Location: Kansas City Area
Posts: 1,761

Teggy - '98 Acura Integra LS
Sports Cars
90 day: 32.74 mpg (US)

IMA - '10 Honda Insight EX
Team Honda
90 day: 34.76 mpg (US)

Tessie - '06 Acura TSX Base
90 day: 28.2 mpg (US)
Thanks: 31
Thanked 41 Times in 35 Posts
Some properties of Thermodynamics apply...

As I understand it, when you place the room-temperature items in the fridge, the resultant temperature difference places a demand on the system due to the ambient temp drop, which = more energy consumed. Then once up to temperature, the demand is flat.

The biggest loss that should be inspected is, "how often is the door opened"? You lose a tremendous amount of cool air each time you open that door -- some people leave it open until the cereal is covered in milk! ...than back it goes.

Also consider the minimum temp settings.

All user-specific.

RH77
__________________
“If we knew what we were doing, it wouldn't be called research” ― Albert Einstein

_
_
  Reply With Quote
Old 10-29-2008, 09:17 AM   #4 (permalink)
EcoModding Lurker
 
Join Date: Apr 2008
Location: Sioux Falls, SD
Posts: 36

chevynova - '88 Chevy Nova
90 day: 31.84 mpg (US)

Fit - '08 Honda Fit Sport MT
90 day: 39.63 mpg (US)
Thanks: 0
Thanked 0 Times in 0 Posts
Both of the above posts have very good points. Put empty milk jugs full of water in there as you get room.

I've never heard that fridges run more efficiently b/c they have nothing to cool. Also what your talking about isn't necessarily efficiency of the fridge but cumulative demand (e.g. we're not talking about the mileage but rather the total distance driven). If the fridge were perfectly insulated and sealed, it would run only once each time you open the door to recover from the air changes. Because of physics in our macroscopic world this is impossible, and your refrigerator gains heat through conduction and infiltration. The idea is that convection (to items in fridge) and conduction (internal to each item) is a slower process than the air changes in your fridge. This allows for the significant energy rise to be absorbed my as much mass as possible (also reducing the total volume of air which can be exchanged) which results in only maybe ~1 or 2 degree temperature change as opposed to if your fridge was empty the temperature change would be much more significant.

This is why I like having my bottom freezer fridge with 2 half doors. I can open just the door that has pop behind it minimizing the air change in the space, as opposed to opening the full size door nearly all the way to get something that's near the hinge.
__________________
  Reply With Quote
Old 10-29-2008, 09:29 AM   #5 (permalink)
Master EcoModder
 
Join Date: Jul 2008
Location: Tallmadge, OH
Posts: 313
Thanks: 6
Thanked 26 Times in 21 Posts
An empty frige uses the least energy only because there is no need to plug it in. An almost full fridge is the most efficient state. The mass of cold solids and liquids hold heat better than air alone.

If you go with the water jug idea, fill the jugs with the water from the shower the next time you are waiting for the water to warm up. In summer, when jugs are unused, keep them in the basement or other cool place. In the winter perhaps an enclosed porch.
  Reply With Quote
Old 10-29-2008, 10:23 AM   #6 (permalink)
Master EcoModder
 
Join Date: Jun 2008
Location: London, Ontario
Posts: 1,096

2k2Prot5 - '02 Mazda Protege5
90 day: 33.82 mpg (US)
Thanks: 0
Thanked 17 Times in 14 Posts
putting warm jugs of water into your fridge is a terrible idea. Instead of cooling 1L of air, you now have to cool 1L of water, then when you need the space, you take that 1L of cold out and it warms up beside the fridge.

Just use it like normal, keep the temp as warm as you can and don't leave the door open. If its old, get it the heck out and put a good one in. If the seals are broken, replace them or replace the fridge.
  Reply With Quote
Old 10-29-2008, 10:23 AM   #7 (permalink)
MechE
 
Join Date: Dec 2007
Location: Bay Area
Posts: 1,151

The Miata - '01 Mazda MX-5 Miata
Thanks: 0
Thanked 22 Times in 18 Posts
Quote:
Originally Posted by Sean T. View Post
In theory, wouldn't it be the most efficient to load a few items at a time, so the fridge doesn't need to work too hard? And then try to fit all of the food in the fridge so it holds the cold temperature easier and again, the fridge doesn't need to work too hard?
Nope, load it all at the same time....

1. That food needs X amount of energy to cool down. Slowly adding does not change the number "X" - when you use that energy doesn't matter, you're still going to use it.
2. Your refrigerator is basically a small air conditioner - the refrigerant system operates at/near peak efficiency while in "steady state" conditions. That is, the least efficient operating time is during start up while the compressor attempts to pressurize the high side. During this time you have the lowest Coefficient of Performance (heat moved/work in) - so you're doing a lot of work, and not cooling very much. Once the high side pressure has stabilized, you've reached steady state.



On the subject of refrigerators.... I'd love it if modular systems were mass produced for home use. I'd want a permanent liquid coolant chiller with an exterior condenser - then, just hook up some hoses to your refrigerator and you're good to go I hate that I have to move heat from my refrigerator to my kitchen, then from my kitchen to outside (VIA central a/c). Then, replacing the appliance should be cheaper (aside from initial investment).
__________________
Cars have not created a new problem. They merely made more urgent the necessity to solve existing ones.
  Reply With Quote
The Following User Says Thank You to trebuchet03 For This Useful Post:
roosterk0031 (07-31-2012)
Old 10-29-2008, 10:27 AM   #8 (permalink)
Master EcoModder
 
Join Date: Jun 2008
Location: London, Ontario
Posts: 1,096

2k2Prot5 - '02 Mazda Protege5
90 day: 33.82 mpg (US)
Thanks: 0
Thanked 17 Times in 14 Posts
That is the perfect system. But why throw the heat outside? Put it into your hot water tank! Pre-heat your oven with it! Then when your oven is turned off, speed-cool it with the same liquid to heat up your water heater more! In the winter, warm the house.

When i make my millions, i'll have a wonderfully efficient house built.
  Reply With Quote
Old 10-29-2008, 11:02 AM   #9 (permalink)
MechE
 
Join Date: Dec 2007
Location: Bay Area
Posts: 1,151

The Miata - '01 Mazda MX-5 Miata
Thanks: 0
Thanked 22 Times in 18 Posts
Quote:
Originally Posted by MazdaMatt View Post
That is the perfect system. But why throw the heat outside? Put it into your hot water tank! Pre-heat your oven with it! Then when your oven is turned off, speed-cool it with the same liquid to heat up your water heater more! In the winter, warm the house.

When i make my millions, i'll have a wonderfully efficient house built.
My utility used to give rebates for having a heat recovery system on your a/c
__________________
Cars have not created a new problem. They merely made more urgent the necessity to solve existing ones.
  Reply With Quote
Old 07-31-2012, 05:30 PM   #10 (permalink)
EcoModding Lurker
 
Join Date: Jul 2012
Location: Berlin
Posts: 17
Thanks: 1
Thanked 14 Times in 7 Posts
Another point is that you should be aware of what is in the fridge and what will be rott away soon. And there for your fridge should not be too full.

  Reply With Quote
Reply  Post New Thread




Similar Threads
Thread Thread Starter Forum Replies Last Post
Ordered an Aptera typ-1h Ptero General Efficiency Discussion 28 08-30-2019 10:07 AM
Mass Transit Sadness i_am_socket General Efficiency Discussion 8 07-31-2008 04:13 PM
DIY - Ambient Air Fridge NoCO2 Saving@Home 13 05-10-2008 10:18 AM



Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com