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Main
Date: 26 Jul 2006 04:53:30
From: Todd Carter
Subject: Build a refrigerator
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I've been looking for an upright freezer to replace my failing chest
freezer. It must have removable shelves (no coils), be big enough for
4-6 cornies, a 20# CO2 tank, several six packs and 15 quart jars of
pickles. I haven't found a used one that fits the bill and a new 20ft3
runs around $600. Ouch.
Refrigerator/freezers aren't large enough or are even more expensive.
Came across this page
www.plamondon.com/rural-living/new-life-for-old-refrigerators.html
and this
http://home.swbell.net/bufkin/cold_storage_box.htm
and thought building a big insulated box around a window air conditioner
would meet all my needs without breaking my wallet. I'm pretty good
with carpentry and have already built a lager frig box to go underneath
a dorm frig. I could mount the window unit through an outside wall and
into the frig box directly or by ducting one or both sides.
I've identified a few possible hitches: Can a 5000-6000 Btu window unit
with the thermostat replaced by a controller really drop a 30-50 ft3
insulated box down into the mid 30sF? Will this use kill it in a year
or two? Does it need to have a vent fan for below freezing days or a
damper to exhaust inside the house (save heating)? How to keep the
evaporator coil from freezing and still get the box into the 30s.
Anyone do this? Advice?
Todd
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Date: 26 Jul 2006 16:31:23
From: Duke
Subject: Re: Build a refrigerator
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Those type of AC units are not particularly cheap to run.
You may spend more in the long run on electric bills than you would just
buying a new fridge to begin with.
Just a thought,
Duke
"Todd Carter" <txspamcarter@kc.rr.com > wrote in message
news:ezCxg.7860$D%4.920@tornado.rdc-kc.rr.com...
> I've been looking for an upright freezer to replace my failing chest
> freezer. It must have removable shelves (no coils), be big enough for 4-6
> cornies, a 20# CO2 tank, several six packs and 15 quart jars of pickles.
> I haven't found a used one that fits the bill and a new 20ft3 runs around
> $600. Ouch.
> Refrigerator/freezers aren't large enough or are even more expensive.
>
> Came across this page
> www.plamondon.com/rural-living/new-life-for-old-refrigerators.html
> and this
> http://home.swbell.net/bufkin/cold_storage_box.htm
> and thought building a big insulated box around a window air conditioner
> would meet all my needs without breaking my wallet. I'm pretty good with
> carpentry and have already built a lager frig box to go underneath a dorm
> frig. I could mount the window unit through an outside wall and into the
> frig box directly or by ducting one or both sides.
> I've identified a few possible hitches: Can a 5000-6000 Btu window unit
> with the thermostat replaced by a controller really drop a 30-50 ft3
> insulated box down into the mid 30sF? Will this use kill it in a year or
> two? Does it need to have a vent fan for below freezing days or a damper
> to exhaust inside the house (save heating)? How to keep the evaporator
> coil from freezing and still get the box into the 30s.
>
> Anyone do this? Advice?
>
> Todd
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Date: 27 Jul 2006 04:49:50
From: Todd Carter
Subject: Re: Build a refrigerator
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I plan to buy a 10.7 EER or better unit, which should be much cheaper to
run than the ones from even a few years ago. No doubt it will be a
multiple of the ~$40 on the energy guide. (I wonder how much it costs
to run my 20-30 year old chest freezer that's on its way out.)
I wish I could buy or obtain a frig or freezer large enough to house
everything. Freezers often have the evaporator coils integrated into
the shelves and basic refrigerators aren't big enough. Risk vs reward.
Todd
Duke wrote:
> Those type of AC units are not particularly cheap to run.
> You may spend more in the long run on electric bills than you would just
> buying a new fridge to begin with.
>
> Just a thought,
>
> Duke
>
>
> "Todd Carter" <txspamcarter@kc.rr.com> wrote in message
> news:ezCxg.7860$D%4.920@tornado.rdc-kc.rr.com...
>> I've been looking for an upright freezer to replace my failing chest
>> freezer. It must have removable shelves (no coils), be big enough for 4-6
>> cornies, a 20# CO2 tank, several six packs and 15 quart jars of pickles.
>> I haven't found a used one that fits the bill and a new 20ft3 runs around
>> $600. Ouch.
>> Refrigerator/freezers aren't large enough or are even more expensive.
>>
>> Came across this page
>> www.plamondon.com/rural-living/new-life-for-old-refrigerators.html
>> and this
>> http://home.swbell.net/bufkin/cold_storage_box.htm
>> and thought building a big insulated box around a window air conditioner
>> would meet all my needs without breaking my wallet. I'm pretty good with
>> carpentry and have already built a lager frig box to go underneath a dorm
>> frig. I could mount the window unit through an outside wall and into the
>> frig box directly or by ducting one or both sides.
>> I've identified a few possible hitches: Can a 5000-6000 Btu window unit
>> with the thermostat replaced by a controller really drop a 30-50 ft3
>> insulated box down into the mid 30sF? Will this use kill it in a year or
>> two? Does it need to have a vent fan for below freezing days or a damper
>> to exhaust inside the house (save heating)? How to keep the evaporator
>> coil from freezing and still get the box into the 30s.
>>
>> Anyone do this? Advice?
>>
>> Todd
>
>
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Date: 26 Jul 2006 10:02:32
From: Mark R
Subject: Re: Build a refrigerator
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"Todd Carter" <txspamcarter@kc.rr.com > wrote in message
news:ezCxg.7860$D%4.920@tornado.rdc-kc.rr.com...
> I've been looking for an upright freezer to replace my failing chest
> freezer. It must have removable shelves (no coils), be big enough for
> 4-6 cornies, a 20# CO2 tank, several six packs and 15 quart jars of
> pickles. I haven't found a used one that fits the bill and a new 20ft3
> runs around $600. Ouch.
> Refrigerator/freezers aren't large enough or are even more expensive.
>
> Came across this page
> www.plamondon.com/rural-living/new-life-for-old-refrigerators.html
> and this
> http://home.swbell.net/bufkin/cold_storage_box.htm
I've seen Big Bertha in person and it worked great for fermenting ales and
lagers, and was good for cool storage. Can't tell you what would happen if
you replaced the thermostat but I would guess that freezing the evap coils
would become an issue if you tried to get it into the 30's. I used to
service a walk-in unit for the USCG that was set at 45 for veggies and even
that one would have freeze issues if the air circulation was poor. If you
mounted the A/C unit up high in the box the few degrees difference between
the top and bottom of the box might be enough to keep it defrosted.
Mark R
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Date: 26 Jul 2006 08:21:59
From: Dick Adams
Subject: Re: Build a refrigerator
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Todd Carter <txspamcarter@kc.rr.com > wrote:
> I've been looking for an upright freezer to replace my failing chest
> freezer. It must have removable shelves (no coils), be big enough for
> 4-6 cornies, a 20# CO2 tank, several six packs and 15 quart jars of
> pickles. I haven't found a used one that fits the bill and a new 20ft3
> runs around $600. Ouch.
Finding a 20 cuft upright without shelf coils is a real trick.
$600 for a new 29 footer is a decent price.
> Refrigerator/freezers aren't large enough or are even more expensive.
They are not large enough, but they are available for free.
> Came across this page
> www.plamondon.com/rural-living/new-life-for-old-refrigerators.html
> and this
> http://home.swbell.net/bufkin/cold_storage_box.htm
Once you have seen Bufkin's Big Bertha, you have seen it all.
> and thought building a big insulated box around a window air conditioner
> would meet all my needs without breaking my wallet. I'm pretty good
> with carpentry and have already built a lager frig box to go underneath
> a dorm frig. I could mount the window unit through an outside wall and
> into the frig box directly or by ducting one or both sides.
> I've identified a few possible hitches: Can a 5000-6000 Btu window unit
> with the thermostat replaced by a controller really drop a 30-50 ft3
> insulated box down into the mid 30sF? Will this use kill it in a year
> or two? Does it need to have a vent fan for below freezing days or a
> damper to exhaust inside the house (save heating)? How to keep the
> evaporator coil from freezing and still get the box into the 30s.
>
> Anyone do this? Advice?
I was going to do it and didn't because I got a fermentation
frig for free. I see no reason why it should not work.
Dick
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Date: 26 Jul 2006 05:11:56
From: Steve/Aus
Subject: Re: Build a refrigerator
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"Todd Carter" <txspamcarter@kc.rr.com > wrote in message
news:ezCxg.7860$D%4.920@tornado.rdc-kc.rr.com...
> I've been looking for an upright freezer to replace my failing chest
> freezer. It must have removable shelves (no coils), be big enough for 4-6
> cornies, a 20# CO2 tank, several six packs and 15 quart jars of pickles.
> I haven't found a used one that fits the bill and a new 20ft3 runs around
> $600. Ouch.
> Refrigerator/freezers aren't large enough or are even more expensive.
>
> Came across this page
> www.plamondon.com/rural-living/new-life-for-old-refrigerators.html
> and this
> http://home.swbell.net/bufkin/cold_storage_box.htm
> and thought building a big insulated box around a window air conditioner
> would meet all my needs without breaking my wallet. I'm pretty good with
> carpentry and have already built a lager frig box to go underneath a dorm
> frig. I could mount the window unit through an outside wall and into the
> frig box directly or by ducting one or both sides.
> I've identified a few possible hitches: Can a 5000-6000 Btu window unit
> with the thermostat replaced by a controller really drop a 30-50 ft3
> insulated box down into the mid 30sF? Will this use kill it in a year or
> two? Does it need to have a vent fan for below freezing days or a damper
> to exhaust inside the house (save heating)? How to keep the evaporator
> coil from freezing and still get the box into the 30s.
>
> Anyone do this? Advice?
>
> Todd
You can get proper units for this purpose designed for small cool rooms.
One idea that has crossed my mind is to make a propylene-glycol unit.
Basically a small freezer - the smallest available, with a tank of
propylene-glycol in it. Copper or plastic tubing and a small pump to
circulate the chilled PG to anywhere, such as a heat exchanger (car
transmission cooler?) with a small fan for an insulated box, a beer line
chiller perhaps, in fact anywhere you need icy-cold. A crude idea at this
stage but worth thought.
Steve W (in Aus)
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Date: 26 Jul 2006 19:05:23
From: Bob
Subject: Re: Build a refrigerator
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"Todd Carter" <txspamcarter@kc.rr.com > wrote in message
news:ezCxg.7860$D%4.920@tornado.rdc-kc.rr.com...
> I've been looking for an upright freezer to replace my failing chest
> freezer. It must have removable shelves (no coils), be big enough for
> 4-6 cornies, a 20# CO2 tank, several six packs and 15 quart jars of
> pickles. I haven't found a used one that fits the bill and a new 20ft3
> runs around $600. Ouch.
> Refrigerator/freezers aren't large enough or are even more expensive.
>
> Came across this page
> www.plamondon.com/rural-living/new-life-for-old-refrigerators.html
> and this
> http://home.swbell.net/bufkin/cold_storage_box.htm
> and thought building a big insulated box around a window air conditioner
> would meet all my needs without breaking my wallet. I'm pretty good
> with carpentry and have already built a lager frig box to go underneath
> a dorm frig. I could mount the window unit through an outside wall and
> into the frig box directly or by ducting one or both sides.
> I've identified a few possible hitches: Can a 5000-6000 Btu window unit
> with the thermostat replaced by a controller really drop a 30-50 ft3
> insulated box down into the mid 30sF? Will this use kill it in a year
> or two? Does it need to have a vent fan for below freezing days or a
> damper to exhaust inside the house (save heating)? How to keep the
> evaporator coil from freezing and still get the box into the 30s.
>
> Anyone do this? Advice?
Put a thermometer in front of such an A/C. I bet it gets nowhere near 30F.
It would need to go even lower to cool a significant space to the 30's.
For a closer test, put the thermometer into a BIG cardboard box, and prop
that up to the A/C for awhile, then check the temp.
A/Cs are not designed to reach low temps.
Bob
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Date: 27 Jul 2006 06:02:51
From: Todd Carter
Subject: Re: Build a refrigerator
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No, a stock AC will not get the air that cold before the thermostat
shuts it off. I will be replacing the thermostat with a temp controller
and instead of an entire room, I'll be cooling a small fraction of the
volume.
Air conditioners, dehumidifiers, refrigerators and freezers are all the
same machine and do the same thing, transfer heat. The only difference
is the size and placement of components and label on the box. The size
of the compressor and amount of surface area/circulation on the
evaporator coil (and condenser, outside temp, humidity) determine how
much heat can be removed. None of them do it all instantly by blowing
out 30F air as you suggest or you would have a small freezer at 30F
within minutes of plugging it in. They must recirculate the air and
keep removing heat.
Eventually, a balance point is reached based on heat leakage into the
box (insulation) and the system's ability to remove it. I don't know
what the magic number is for BTUs required to volume and insulation, but
read this:
www.plamondon.com/rural-living/new-life-for-old-refrigerators.html
Bob wrote:
> Put a thermometer in front of such an A/C. I bet it gets nowhere near 30F.
> It would need to go even lower to cool a significant space to the 30's.
> For a closer test, put the thermometer into a BIG cardboard box, and prop
> that up to the A/C for awhile, then check the temp.
> A/Cs are not designed to reach low temps.
>
> Bob
>
>
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Date: 26 Jul 2006 23:16:29
From: Bob
Subject: Re: Build a refrigerator
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Don't different systems have different optimal operating temp ranges?
Different heat exchangers, evaporators,and other components, and
the refrigerant would affect whether a system works well at cold temps.
Bypassing the A/C thermostat and doing the box test will quickly demonstrate
if it will work at all.
Bob
"Todd Carter" <txspamcarter@kc.rr.com > wrote in message
news:fGYxg.2563$zg.79@tornado.rdc-kc.rr.com...
> No, a stock AC will not get the air that cold before the thermostat
> shuts it off. I will be replacing the thermostat with a temp controller
> and instead of an entire room, I'll be cooling a small fraction of the
> volume.
> Air conditioners, dehumidifiers, refrigerators and freezers are all the
> same machine and do the same thing, transfer heat. The only difference
> is the size and placement of components and label on the box. The size
> of the compressor and amount of surface area/circulation on the
> evaporator coil (and condenser, outside temp, humidity) determine how
> much heat can be removed. None of them do it all instantly by blowing
> out 30F air as you suggest or you would have a small freezer at 30F
> within minutes of plugging it in. They must recirculate the air and
> keep removing heat.
>
> Eventually, a balance point is reached based on heat leakage into the
> box (insulation) and the system's ability to remove it. I don't know
> what the magic number is for BTUs required to volume and insulation, but
> read this:
> www.plamondon.com/rural-living/new-life-for-old-refrigerators.html
>
>
> Bob wrote:
>
> > Put a thermometer in front of such an A/C. I bet it gets nowhere near 30F.
> > It would need to go even lower to cool a significant space to the 30's.
> > For a closer test, put the thermometer into a BIG cardboard box, and prop
> > that up to the A/C for awhile, then check the temp.
> > A/Cs are not designed to reach low temps.
> >
> > Bob
> >
> >
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Date: 27 Jul 2006 10:05:17
From: Mark R
Subject: Re: Build a refrigerator or A/C 0101
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"Bob" <bobnospam@gmail.com > wrote in message
news:It6dnSKosPHPx1XZnZ2dnUVZ_oCdnZ2d@comcast.com...
> Don't different systems have different optimal operating temp ranges?
> Different heat exchangers, evaporators,and other components, and
> the refrigerant would affect whether a system works well at cold temps.
>
> Bypassing the A/C thermostat and doing the box test will quickly
demonstrate
> if it will work at all.
Yep and to figure the optimal takes enough math to choke a.....
A/C 0101
The evap coil size, CFM air flow, and refrigerant flow, are all
interrelated. At optimal temp the "compressed" liquid refrigerant enters the
evap either through a set size orifice or a regulated (TXV) valve depending
on the system. For your basic window unit it's usually the orifice. It
begins to expand and evaporate as it flows through the evaporator coils and
ideally reaches 100% evaporation as it exits the evap coils on it's way to
the compressor. Freezing of the coils is likely to start if the refrigerant
doesn't fully evaporate. This can be caused by low CFM air flow or operating
it below it's designed low temp range. At that point liquid refrigerant is
making it past the evap coil and if it reaches the compressor can damage or
at the least shorten it's life.
So.... The more efficient A/C units built today won't have a bunch of
"fudge" factor built into them as it's not cost effective and lowers the
energy ratings. Changing the thermostat may get you into the 40's but I
wouldn't hope for much more than that. Getting into the 30's would require
push and balancing most of the factors mentioned above And freezing would be
a constant concern.
IIRC it was Steve (smhoneydo) that used the mechanicals of an old fridge to
build a cooler into his bar. You might want to go that route if you are
mechanically inclined.
Mark R
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