Converting a chest freezer to my daily use refrigerator

[Edward J]

"--------and I was jut itching to get rid of one chest freezer that was hogging space in the kitchen. I scrounged up a pick-up truck and drove off to the city dump.------"

 

There are all kinds of rules/laws regarding the disposal of refrigeration machinery. Check with your local authorities first.

 

dcarch

 

Absolutely.  

 

This is why I took the freezer to the city dump, paid my $20.00 fee for large appliances, and followed the city employee  instructions.

[Martin Fisher]

We take all large appliances to the scrap yard here and receive cash.
The only rule is that the compressor must be removed from fridges and freezer.
They pay different prices for compressors and bodies.

[Edward J]

 

Actually, please consider Chris' comment above, "---I also caution you that your energy savings are probably not going to be measurable just switching between a chest and upright variety. It actually takes very little energy to cool the air in the fridge, so opening and closing the door is not as costly as you might guess."

 

I don't remember the exact numbers. The energy lost from opening a refrigerator door is extremely little. You can do a calculation, specific heat of air x volume x degrees = BTUs. BTW, Chris is a trained scientist.

 

dcarch

 

 

I don't know about this, certainly it doesn't hold true for most commercial refrigeration units--either reach-in or walk-in. 

 

The problem with this formula is that it doesn't factor in that warm air contains more moisture than cold air. And typically kitchens are pretty warm places.  When you open a fridge door, warm air flows into the chamber and will "stick" to the evaporator coil where it will ultimately form ice.  If and when enough ice forms on the coil, the compressor shuts down and the cabinet temperature starts to climb--getting warmer and warmer.  The defrost cycle SHOULD take care of this, and in most commercial refrigeration this is a 20m min cycle every 8 hrs.  However, if a coil is plugged badly enough with ice, the defrost cycle won't have enough time to melt.  This is why you will see plastic curtain strips on many commercial walk-ins, and why many new reach in fridges/freezers have an alarm that will go off if the door is open for longer than 30-45 seconds.  

[dcarch]

I don't know about this, certainly it doesn't hold true for most commercial refrigeration units--either reach-in or walk-in. 

 

 

Whatever the refrigeration machine is, it still has to follow physics laws. I am aware of the following situation:

 

When you open the door to a smoker, you feel a blast of hot air, and you get yelled at, " If you are looking, you are not cooking".

 

When you open the door to your freezer to get food when the power is out, you feel a blast of chill air, and you get yelled at for ruining all the food in the freezer.

 

But the following is the reality:

 

Specific Heat of air =.018 Btus per cubic foot.

Assuming room temperature is 80F, and refrigerator temperature is 35F, 80F – 35F = 45F x .018 = 0.81 BTU

Assuming you have 8 cu ft of free air in your refrigerator and 100% of the air is replaced with room temperature air:

8 x 0.81 = 3.24 BTUs is all the energy you need to cool the air back down. That’s less than 2 watt of electric power.

 

And for a freezer, relatively full, with one cu ft of free air, at -5F, you are talking about only 1.62 BTU lost.

 

dcarch

[Martin Fisher]

Assuming both units are well insulated......It boils down to how often you'll open and close the unit...if you'll open and close the unit rarely...there's basically no difference.

Open and close the unit frequently and the chest has an advantage.

 

The cold air doesn't flow out of the chest the way it does out of an upright.....you can very easily see this in monitoring thermometer and controller response.

[Edward J]

Whatever the refrigeration machine is, it still has to follow physics laws. I am aware of the following situation:

 

When you open the door to a smoker, you feel a blast of hot air, and you get yelled at, " If you are looking, you are not cooking".

 

When you open the door to your freezer to get food when the power is out, you feel a blast of chill air, and you get yelled at for ruining all the food in the freezer.

 

But the following is the reality:

 

Specific Heat of air =.018 Btus per cubic foot.

Assuming room temperature is 80F, and refrigerator temperature is 35F, 80F – 35F = 45F x .018 = 0.81 BTU

Assuming you have 8 cu ft of free air in your refrigerator and 100% of the air is replaced with room temperature air:

8 x 0.81 = 3.24 BTUs is all the energy you need to cool the air back down. That’s less than 2 watt of electric power.

 

And for a freezer, relatively full, with one cu ft of free air, at -5F, you are talking about only 1.62 BTU lost.

 

dcarch

 

 

No, what I'm talking about is the coil all iced up. 

 

As I stated above, warm air contains more moisture than cold air, and this warm air, upon enetering the cabinet, sticks onto the (very cold) coil, forming ice.  If enough ice builds up--that is to say that the door was opened multiple times for extened periods of time and/or the air is humid (ie hot August day, or a steamy kitchen) then the coil plugs up with ice, and the fan can't circulate  properly.  The temperature goes up, causing the compressor to run constantly, as opposed to bursts of 5-7 minutes every 15-20 minutes.  The compressor, under full load, will consume much more electricity than in bursts of 5-7 minutes.  Eventually the heat overload switch kicks and the compressor shuts down.

 

While working in S'pore and S.E. Asia this was a common problem with walk-ins.  The quickest and easiest fix is to shut down the unit, hook up a hose and give the coil and "Enema", that is, to wash it down with warm water and dissolve the ice.  This does the trick, but it is prudent to install plastic strip curtains and to give holy sh*t to anyone leaving the door open for longer than a minute.

 

Granted, chest freezers don't have this problem, but if using them for their intended purpose ice does build up on the walls, and it isn't all that fun to scrape ice off, or muck out the tub when it needs to be done.

Edited December 9, 2014 by Edward J (log)

[Ashen]

Only one side has the coils and they're packed tightly enough that I wouldn't attempt to drill between them. Just drill from the side that doesn't have coils.

 

The typical  arrangement for a chest freezer is the   evaporation coils are  attached to the inside skin of  the liner,   and the condensation coils are attached to the outside skin of the cabinet , with the insulation in between.   here is a link to a picture that gives a breakdown .   Different companies don't all arrange the location of their coils in the same manner or even use the same pattern .  spiral or zig zag patterns mostly.  Most are installed ,  spaced  and attached by hand , so you won't get precise location data .  When I was younger , I literally attached hundreds of thousands of evap coils to the inside liners of chest freezers, and condenser coils to the outside cabinets of frost free upright fridges and freezers. 

[dcarch]

No, what I'm talking about is the coil all iced up. 

 

"---I don't know about this, certainly it doesn't hold true for most commercial refrigeration units--either reach-in or walk-in. ---"

 

"-------------------  The quickest and easiest fix is to shut down the unit, hook up a hose and give the coil and "Enema", that is, to wash it down with warm water and dissolve the ice.  This does the trick,---------------------"

 

I think most commercial units are also frost -free.

 

dcarch

[dcarch]

I am not sure you need to drill to attach tracks.

 

Epoxy works well. I have done it.

 

 

dcarch

[Edward J]

I think most commercial units are also frost -free.

 

dcarch

On this post, you have my quotes out of context, and you're not making much sense.

 

Whole thing reminds me of the "cooling down large amounts of stock" thread, where, after giving you explicit instructions--twice--on the preferred method of cooling down stock (endorsed by many health dept's) you failed to use a cold water bath in your "experiment" and claimed this method was useless.

[dcarch]

Sorry if you feel I quoted you out of context.

 

I disagree with your statement that most commercial units are not frost free.

 

dcarch