We are looking at chest freezers, and have space available in an
unheated shack, or porch, but I vaguely remember that this may not be a
good idea - or does that just apply to fridge/freezers?

We are in NE Scotland, and the porch gets very cold in winter. Could
that be a problem?

Thanks.
--
Graeme

On 19/09/2010 09:32, Graeme wrote:

We are looking at chest freezers, and have space available in an
unheated shack, or porch, but I vaguely remember that this may not be a
good idea - or does that just apply to fridge/freezers?

It's all about thermostat operation: most fridge-freezers have one
thermostat which maintains the fridge at 4 deg or whatever, and the
freezer just has to tag along with whatever the fridge decided to do.
That's fine in normal house temperatures, but if the ambient temperature
goes below 4 deg the thermostat will not cut in, so the freezer part is
also not cooled.

Personally I've had a separate fridge and freezer in my garage for years
without problems.

David

In message , Lobster
writes

It's all about thermostat operation: most fridge-freezers have one
thermostat which maintains the fridge at 4 deg or whatever, and the
freezer just has to tag along with whatever the fridge decided to do.
That's fine in normal house temperatures, but if the ambient
temperature goes below 4 deg the thermostat will not cut in, so the
freezer part is also not cooled.

Thanks - yes, that is the part that I thought I remembered. The temp.
here was -19 last winter, and the unheated porch/shack was about the
same temperature. I'm assuming that a standard chest freezer would
still function as normal.

The porch is of wooden construction, not brick, so tends not to absorb
or hold any heat.
--
Graeme

On Sep 19, 11:21*am, Graeme wrote:
In message , Lobster
writes



It's all about thermostat operation: most fridge-freezers have one
thermostat which maintains the fridge at 4 deg or whatever, and the
freezer just has to tag along with whatever the fridge decided to do.
That's fine in normal house temperatures, but if the ambient
temperature goes below 4 deg the thermostat will not cut in, so the
freezer part is also not cooled.

Thanks - yes, that is the part that I thought I remembered. *The temp.
here was -19 last winter, and the unheated porch/shack was about the
same temperature. *I'm assuming that a standard chest freezer would
still function as normal.

The porch is of wooden construction, not brick, so tends not to absorb
or hold any heat.

Get one thats rated for that environment temp range, or itll rust away
rapidly, and may not work as intended.


NT

On 19/09/2010 12:20, John Rumm wrote:
On 19/09/2010 09:32, Graeme wrote:

We are looking at chest freezers, and have space available in an
unheated shack, or porch, but I vaguely remember that this may not be a
good idea - or does that just apply to fridge/freezers?

We are in NE Scotland, and the porch gets very cold in winter. Could
that be a problem?

You need to be careful with what you buy - only some of those available
are suitable for use in outbuildings etc (they usually say in the specs).

What's the issue though, other than the single fridge/freezer thermostat
thing?

I just ask, because I can well imagine that 'outbuilding-rated'
equipment would cost a packet; wondering whether it's worth it (thinking
of my own ebayed garage fridge and freezer which cost pennies and are
running fine after years...)

David

In article ,
Graeme writes:

We are looking at chest freezers, and have space available in an
unheated shack, or porch, but I vaguely remember that this may not be a
good idea - or does that just apply to fridge/freezers?

We are in NE Scotland, and the porch gets very cold in winter. Could
that be a problem?

When you have a refrigeration system with a compressor in the cold,
and some other part of the system warmer (such as indoors), and it
isn't running for some time so it gets cold, you have to heat the
compressor oil. This stops the refrigerant condensing into it.
Don't know if this is likely to be a problem if the whole system
is in the cold. OTOH, the oil itself may start waxing up at the
sorts of temperatures you are talking about, which might prevent
the compressor starting and will reduce the bearing lubrication.

What you could do is make up an external crankcase heater which
you attach to the compressor and run it from a froststat in the
garage. Don't know if it would be necessary - you'll probably
only find out by seeing if it works without one, and without
burning out the compressor. I would have thought 5-10W would be
enough, attached low down on the compressor.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On 19/09/2010 14:53, Andrew Gabriel wrote:
In ,
writes:

We are looking at chest freezers, and have space available in an
unheated shack, or porch, but I vaguely remember that this may not be a
good idea - or does that just apply to fridge/freezers?

We are in NE Scotland, and the porch gets very cold in winter. Could
that be a problem?

When you have a refrigeration system with a compressor in the cold,
and some other part of the system warmer (such as indoors), and it
isn't running for some time so it gets cold, you have to heat the
compressor oil. This stops the refrigerant condensing into it.
Don't know if this is likely to be a problem if the whole system
is in the cold. OTOH, the oil itself may start waxing up at the
sorts of temperatures you are talking about, which might prevent
the compressor starting and will reduce the bearing lubrication.

What you could do is make up an external crankcase heater which
you attach to the compressor and run it from a froststat in the
garage. Don't know if it would be necessary - you'll probably
only find out by seeing if it works without one, and without
burning out the compressor. I would have thought 5-10W would be
enough, attached low down on the compressor.

I have found the climate classes below but none appear to go cool enough
for your requirements. You could try enquiring of a commercial freezer
supplier.

Freezer climate class

Every freezer has a 'climate class', which tells you the range of room
temperatures with which it can cope.

Freezers: Climate class temperatures

Climate class Temperature range (oC)
N 16-32
SN 10-32
ST 18-38
T 18-43

On 19/09/2010 14:53, Andrew Gabriel wrote:
In ,
writes:

We are looking at chest freezers, and have space available in an
unheated shack, or porch, but I vaguely remember that this may not be a
good idea - or does that just apply to fridge/freezers?

We are in NE Scotland, and the porch gets very cold in winter. Could
that be a problem?

When you have a refrigeration system with a compressor in the cold,
and some other part of the system warmer (such as indoors), and it
isn't running for some time so it gets cold, you have to heat the
compressor oil. This stops the refrigerant condensing into it.
Don't know if this is likely to be a problem if the whole system
is in the cold. OTOH, the oil itself may start waxing up at the
sorts of temperatures you are talking about, which might prevent
the compressor starting and will reduce the bearing lubrication.


it would be interesting to know the temperatures at which waxing etc
takes place. All I can add is that I've had a freezer in the cellar for
5 years now, and the ambient temperature range is 0C to 18C, freezer
temp -15 to -20C (when I've looked at the thermometer). Never had any
problem.

If you don't need fairly constant access, putting the freezer in the
coldest part of the home seems most sensible anyway.

Rob

In article ,
Rob writes:
On 19/09/2010 14:53, Andrew Gabriel wrote:
In ,
writes:

We are looking at chest freezers, and have space available in an
unheated shack, or porch, but I vaguely remember that this may not be a
good idea - or does that just apply to fridge/freezers?

We are in NE Scotland, and the porch gets very cold in winter. Could
that be a problem?

When you have a refrigeration system with a compressor in the cold,
and some other part of the system warmer (such as indoors), and it
isn't running for some time so it gets cold, you have to heat the
compressor oil. This stops the refrigerant condensing into it.
Don't know if this is likely to be a problem if the whole system
is in the cold. OTOH, the oil itself may start waxing up at the
sorts of temperatures you are talking about, which might prevent
the compressor starting and will reduce the bearing lubrication.


it would be interesting to know the temperatures at which waxing etc
takes place. All I can add is that I've had a freezer in the cellar for
5 years now, and the ambient temperature range is 0C to 18C, freezer
temp -15 to -20C (when I've looked at the thermometer). Never had any
problem.

I don't know. It can happen in the expansion jet if too much of
the lubricant gets into the refrigerant pipework, but that's going
to be colder than the normal freezer operating temperature.

If you don't need fairly constant access, putting the freezer in the
coldest part of the home seems most sensible anyway.

In terms of heat loss, yes. However that's not the only factor to
consider. Operating them a long way from their design temperature
may well reduce efficiency in other ways.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On Sun, 19 Sep 2010 09:32:46 +0100, Graeme
wrote:
We are looking at chest freezers, and have space available in an
unheated shack, or porch, but I vaguely remember that this may not be a
good idea - or does that just apply to fridge/freezers?

In addition to what others have already mentioned, there are a couple of
extra potential problems:

The cold outer skin of the freezer can cause condensation to form, and if
this soaks into/through the insulation it can freeze against the inner
skin. The ice is not a good insulator, so the compressor has to run more
often to try to keep the temperature down.

The way a fridge or freezer operates requires the liquid refrigerant to be
in the correct temperature range after it has passed through the heat
exchanger. If it's too cold, then it won't evaporate when it gets to the
expansion chamber, which means no cooling plus problems for the compressor
when it tries to compress liquid.

On Sun, 19 Sep 2010 19:43:39 +0100, Caecilius wrote:

On Sun, 19 Sep 2010 09:32:46 +0100, Graeme
wrote:
We are looking at chest freezers, and have space available in an
unheated shack, or porch, but I vaguely remember that this may not be a
good idea - or does that just apply to fridge/freezers?

In addition to what others have already mentioned, there are a couple of
extra potential problems:

The cold outer skin of the freezer can cause condensation to form, and if
this soaks into/through the insulation it can freeze against the inner
skin. The ice is not a good insulator, so the compressor has to run more
often to try to keep the temperature down.

The way a fridge or freezer operates requires the liquid refrigerant to be
in the correct temperature range after it has passed through the heat
exchanger. If it's too cold, then it won't evaporate when it gets to the
expansion chamber, which means no cooling plus problems for the compressor
when it tries to compress liquid.

I ran one in an outhouse along with a tumble drier for 20 years.
We left the outhouse door open when the drier was operating, but other
than that I never had a problem with either.
--
Jim S
Tyneside UK
www.jimscott.co.uk