Allan,
First of all, thanks for your comments on refrigeration. They are very
helpful.
As to your fourth point, you don't have to burn fossil fuels to generate the
power to run the refrigerators. Neither hydro or nuclear power produce CO2,
although both have their drawbacks. Yet in spite of the advantages of
nuclear power, the current mindset is such that this form of energy
production is not "politically correct" and is not even being considered. I
sometimes wonder why God included U in the suite of elements when he created
the universe if it were not for energy production. Uranium has no other
known uses other than to produce energy (using U as a coloring agent in
pottery went out some time ago). Unless the emerging economies choose
nuclear over fossil fuels, it may be game over for all of us. And who is to
tell them that they should do with less energy than we do? I'm sure my
comments will pry open a large can of worms.
Your fifth point is, IHMO, a very important one. Rather than quibbling
about which refrigerant to use, it might be better to ask if we need the
amount of refrigeration that we have become accustomed to. By simply car
pooling with one other person, we can reduce the energy consumption to go to
work by a factor of two. Having four other members in a car pool reduces
one's energy consumption by 80%.
I would suggest, though, that we don't have to choose between "arguing about
the means of creation" and "being good stewards of creation." We can do
both and I'm sure that most of us are doing both.
As an aside, I attended the first conference of Christian environmentalists
in Edmonton two years ago, where Cal de Witt was one of the featured
speakers. However, I found that there was a wide spectrum in views among
the attendees. I was, for example, surprised at the anti-nuclear stance of
the people I spoke with and I am not convinced that the attendees.
Chuck Vandergraaf
Waste Technology Business Unit
Atomic Energy of Canada Ltd.
Pinawa, MB
----------
From: Allan Harvey[SMTP:aharvey@boulder.nist.gov]
Sent: Friday June 02, 2000 9:45 AM
To: asa@calvin.edu
Subject: RE: Question concerning HFC and Greenfreeze manufacturers
At 09:21 AM 6/2/00 -0400, Vandergraaf, Chuck wrote:
>[Quoting Greenpeace]
>
>Greenfreeze Technology
>Greenfreeze uses a mixture of propane (R290) and isobutane (R60Oa),
or
>isobutane as a pure gas for the refrigerant. This replaces the
>ozone-destroying chemicals currently used in refrigeration systems
>worldwide. The filling quantities are about two thirds less than
what is
>required with HFC-134a and CFC-12, due to the technical and
thermodynamic
>properties of hydrocarbons.
>Propane and butane are natural gases available without licenses all
over the
>world at prices (in a purified form) comparable to those of CFCs.
The energy
>efficiency of the propane/butane refrigerators has been proved to
be as good
>as those cooled with CFCs or HFC-134a.
>Some "Greenfreeze" refrigerators with isobutane use up to 38
percent less
>energy than their identical counterparts with HFC-134a.
Bosch-Siemens
>announced a 50% energy savings with Greenfreeze in their 1993
annual report.
Some of my colleagues here work on properties of alternative
refrigerants,
so I can add a few things here.
1) It has been known for a long time that isobutane (and its
mixtures with
propane) can be a pretty good refrigerant. It would be more widely
used if
not for concerns about safety and liability. I've been told that
isobutane
would be great for auto air conditioners, but the automakers don't
want
(probably with good reason) volatile and flammable hydrocarbons
under the
hood in case of a crash. The story is similar with ammonia which is
a fine
refrigerant but unpleasant if it leaks. Maybe Greenpeace should be
supporting tort reform so that people can make greener refrigerators
without fearing big lawsuits. I think these other refrigerants are
more
widely used in Europe, not because of green concerns but because of
the
legal climate.
2) I don't believe the statement about needing 2/3 less refrigerant.
The
amount of cooling you get in a vapor-compression refrigeration cycle
is
determined to a first approximation by the latent heat of the
refrigerant. Isobutane and R134a have almost identical molar latent
heats
at their normal boiling points. Maybe they are trying to talk about
the
*mass* of refrigerant, since the HFCs have higher molecular weight.
But
that isn't really what matters. Similarly, statements about 38% or
50%
better efficiency seem unlikely. Each refrigerant has a particular
temperature range to which it is best suited; if there is some
temperature
where isobutane is 38% better there may be some other temperature
where it
is 38% worse.
3) They talk about "ozone-destroying chemicals" and then talk about
R134a
and R12. R12 deserves that label, but R134a has zero ozone
depletion
potential. It is a global warming gas, but that doesn't happen
unless it
leaks from the refrigeration system. Of course most refrigerants do
eventually get to the atmosphere when the appliance or auto is
junked, but
that amount is tiny compared to the global warming potential of all
the CO2
from fossil fuels.
4) If the real concern is global warming, the global warming
potential of
the refrigerant itself is pretty irrelevant. The important factor
is the
efficiency of the refrigeration, which determines how much fossil
fuels
have to be burned to generate the electricity to run the appliance.
If
there are applications where isobutane refrigerators are really more
efficient, then that is good in terms of global warming, but that
has
little to do with the global warming potential of isobutane itself.
5) To tie something to the concerns of the ASA list. God calls us
to be
good stewards of the creation. Some stewardship decisions are easy
(not
wasting energy, not littering, considering fuel efficiency when
buying a
car), but then there are cases like this that are not obvious. As
Joel
mentioned and I would agree, simply taking the word of Greenpeace
(or even
of less loopy groups such as the Sierra Club) as to what is good
stewardship is not necessarily wise. Maybe if we Christians spent
less
time arguing about the means of creation, we could be better
equipped to be
good stewards of creation. I know there is some work along that
line
(there is an Evangelical Environmental Network, and Cal DeWitt has
written
some books), but I at least have not paid as much attention to that
area as
I probably should.
-------------------------------------------------------------------------
| Dr. Allan H. Harvey |
aharvey@boulder.nist.gov |
| Physical and Chemical Properties Division | "Don't blame the
|
| National Institute of Standards & Technology | government for what
I |
| 325 Broadway, Boulder, CO 80303 | say, or vice
versa." |
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