Joel,
Seems to me that Greenpeace is (once again) shading the truth. From the web
page you cited, the following:
"At the Olympic site Coca-Cola will have 1700 refrigerators that run on
global warming HFC gases and only 100 Greenfreeze coolers that comply with
Sydney's Environmental Guidelines. This means that HFC greenhouse gases will
cool over 10 million Coca-Cola drinks during the Sydney Olympics - the
world's first "Green Games"."
As you know, the first sentence is incorrect; the refrigerators run on
electricity, not on "global warming HFC gases." HFCs are not consumed,
unless the cooling system is leaking.
As to your question, the only "natural refrigeration systems" I am aware of,
are blocks of ice. Up here, some fishing lodge operators saw blocks of ice
from lakes in the winter and store them in insulated buildings or in
insulated underground facilities. The ice lasts all summer.
However, I became curious and search the Internet for "greenfreeze." The
following is an excerpt from the Greenpeace home page (http://www.
Greenpeace.org.)
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.
Greenfreeze is insulated with cyclopentane blown polyurethane foam. This
replaces the CFC- or HCFC-blown insulation foams currently used in
refrigerators. Cyclopentane has no ozone depletion potential (ODP) and the
effect of its components on global warming is negligible. The insulation
value of cyclopentane blown foam compares favorably with that of CFC-11
blown foam, and is better than HCFC-141b blown foam. According to the UNEP
"In the past two years cyclopentane has emerged as the most promising zero
Ozone Depleting Potential (ODP) alternative to CFC-11 as a blowing agent for
rigid insulation foam."
I have no idea if Greenpeace's claims are correct. I don't know how the
heat capacities of these hydrocarbons compare with those of the HFCs. I,
personally, would not be keen to have propane or isobutane in my house (it's
OK for the barbecue on the porch) in case the cooling system sprung a leak.
Chuck Vandergraaf
Pinwa, MB
----------
From: Joel Cannon[SMTP:jcannon@jcannon.washjeff.edu]
Sent: Friday June 02, 2000 7:47 AM
To: asa@calvin.edu
Subject: Question concerning HFC and Greenfreeze manufacturers
Does anyone on the list have knowledge of Greenfreeze cooling
systems?
I have been reading a Greenpeace feature concering coca-cola's
contribution to global warming through its HFC soft drink machine
(http://www.cokespotlight.org). The group is attempting to encourage
Coke to switch away from HFC-based machines. That sounds
good. However, I am aware that sometimes some in the environmental
movement are not careful with the science of what they are
discussing
and would like to see if their claim can be independently
corroborated.
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-- Joel W. Cannon | (724)223-6146 Physics Department | Washington and Jefferson College | Washington, PA 15301 |
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