Part 1: Is Our Globe Really Warming?
(And if so, how will it affect future mobile air conditioning designs?)
by Richard C Kozinski
This article appeared in Magazine 55, the May/June 2004 edition of Cool Profit$ Magazine
© 2004 All Rights Reserved
About Richard Kozinski's Global Warming Articles
My previous articles in this fine publication have been pretty much limited to enhancing the performance of R-134a mobile air conditioning systems. This and a few future installments will take a dramatic shift and discuss Global Warming, and its potential impact on future mobile air conditioning design.
Contrary to what you might think (we hear it so much on the TV), Global Warming is a very controversial subject, and not at all a done deal. The current administration in Washington believes it may be based on junk science, and has therefore taken a wait-and-see position. European policy makers, assuming that glaciers will melt and ocean levels will rise, see Global Warming as a threat to some of their cities that exist below sea level. They want to totally eliminate R-134a, as it is a “Greenhouse Gas.”
As an alternative to R-134a, a lot of development has been done on CO2
systems in both Europe and the United States. CO2 is also a greenhouse gas, but of less Global Warming potential than R-134a. This writer thinks that implementing the
CO2 system in mobile applications would be a colossal mistake, primarily due to the explosive potential of this very high-pressure system.
Article Goal: This installment will show that an R-134a system, with some leakage improvement, will have almost no affect on increasing global temperature over a fifty-year period. A hypothesis will be presented that may show current Global Warming scenarios are greatly overstated and only partly valid in the absence of rain.
Background: The proponents of the Global Warming scenario say that the increasing level of Greenhouse Gases put out by man will cause the earth's surface temperature to rise 2°F to 6°F (some say even more) in the next 100 years. Scientists have concluded that the earth's temperature has risen 1°F in the last 100 years.
The “Greenhouse” theory is that the sun's radiation, which is short wave, gets through the Greenhouse Gases. However, these gases trap the long wave radiation emitted (given off) by the earth.
The earth's atmosphere is made up approximately of 78% nitrogen, 21% oxygen, and .035% carbon dioxide. Other gases make up the rest. 99% of this atmosphere exists in the first 20 miles of height. The Greenhouse Gases are distributed in those 20 miles.
CO2 is the most prevalent greenhouse gas.
Writer's Hypothesis: The prevailing theory is that as Greenhouse Gases increase, the earth's heat emittance decreases. Based on that, a rise in earth's temperature is required to increase emittance enough to obtain a balance. However, popular (new age) theory that incoming heat to the world must be balanced by outgoing heat from the world is flawed; they've not taken into account the huge heat holding capacity of the ocean!
Rain Carries Heat. Rain is the transport vehicle that takes heat out of the atmosphere and puts it into the ocean. A 2 watt/m2 forcing, which would produce a significant rise in global temperature in 100 years, is basically negated if that heat is put in the ocean, which raises its temperature 1°F in 100 years or more. However, the evaporation of just a little more than 1 inch per year of additional ocean even negates this 1°F increase. Consequently, the temperature of the ocean will stay as it is today. This will be more fully discussed in the section on Global Warming.
R-134a, how much does it really contribute to Global Warming? Visualize a column of atmosphere that's a square mile across and 20 miles high. That column contains about 29.5 million pounds of
CO2. At current rates of CO2 increase (which is about 1.8 parts/million/year) 152,000 pounds will be added in one year to this one square mile column.
Now assume that each year, each of the 200 million vehicles in the world leak 2 ounces (1/8 lb) of R-134a. Since there are about 200 million square miles on earth's total surface, we then have one vehicle per square mile today. So, that one vehicle is leaking 2 oz into this one-mile square by 20-mile high space. If we assume a 50 year time period, and a doubling of cars by year 2054 to 400 million (now two per square mile), but leaking only one ounce each per year due to gradual seal improvement, then the total weight of R-134a leaked in 50 years
will be only 100 ounces or 6.7 pounds into this space.
The CO2 meanwhile will increase by 50 x 152,000 lbs or about 7.6 million pounds. So, in 50 years the one square mile column will now have 29.5 million, plus 7.6 million, or
37.1 million pounds of CO2 and 6.7 pounds of R-134a. The scientists have assigned a Global Warming coefficient of 1300 on R-134a and 1.0 on
CO2. Thus, 6.7 pounds of R-134a acts like about 8700 pounds of
The ratio of CO2 to R-134a is still over 4000:1.0. If we assume a 2°F rise in global temperature, the R-134a would be responsible for about .002°F of this. And this is after applying the 1300 coefficient.
Put another way, if R-134a were totally eliminated today, the 2°F rise would take 50 years and 2 1/2 weeks, instead of just 50 years, with R-134a leaking.
Here's another example that demonstrates just how insignificant any environmental damage can be that's comes from the amount of R-134a used by the average American family. Consider the family has two vehicles, each using 1000 gallons of gasoline a year. And, they have a $1,000.00 heat bill and a $1,000.00 electric bill per year. In total, this family generates 500 million BTU's in that year. That's enough to heat 5 million lbs of water 100°F, or, one square mile of air 10 feet high over 100°F. Now, think that at the same time, their vehicles each leak a 2 oz shot glass of R-134a. It doesn't make sense, does it? Oh, and the heat generated by heating and lighting their home produces quite a bit of
From the above examples, it can be seen that R-134a leakage is really miniscule when all of the Global Warming heat and emissions are taken in total. Concerning leakage, the estimate of cutting it by 50% in 50 years is extremely conservative. New low leakage connections are already available, and compressor seals could be greatly improved relatively soon if so mandated. If 42-volt systems come into automotive use, then a hermetic compressor electrically driven will have no seal to worry about. Leakage could be cut down to 10% or less of what it is today, making R-134a even less visible in the Global Warming scenario. It just doesn't make sense to spend a vast amount of resources for a
CO2 system that may prove to be a debacle.
Major Safety Concerns With CO2. The potential energy of a gas filled pressure vessel is defined by the equation: energy = volume x pressure. The dangerous part of this equation is the pressure. A large balloon inflated to 2 psi may have the same potential energy as a 22-caliber bullet, but common sense tells us which one is more lethal.
This writer some time ago did tests on the well known “bottle bomb” for a court case in which the police and FBI were involved. The bottle bomb, as it is commonly called, is usually a plastic pop bottle into which acidic chemicals and tin foil are placed. Very shortly after being corked, the bottle explodes from the hot gas generated by the chemical reaction. For a 20 oz bottle, this occurs at about 50 psi. But without heat to weaken the plastic, the bottle requires about 200 psi to burst.
Note that the 50-psi explosion is enough to take out a wooden mailbox. The 200-psi explosion is so loud and powerful one needs ear and body protection if near. The suction accumulator, and possibly the oil separator, in a
CO2 system would be about the size of the 20 oz pop bottle. Several years ago, one
CO2 system component did rupture in a test trip in Arizona, causing a big hood dent, but fortunately no injuries.
Just at rest the suction accumulator under the hood will be at 1000 psi in summer temperatures. This accumulator may resemble a 20 oz pop bottle, but contains 20 times the explosive energy. Take a defective weld; mix in a lot of vibration for 5 years or so, and you have the recipe for a serious mishap. In an accident, hoods crumple, exposing this potential bomb to victims in any direction.
As if 1000-psi packed accumulator isn't bad enough, the condenser in a CO2
system may be at 2200 psi. (A shotgun shell generates 6500 psi when fired.) Imagine a headlamp rupturing this condenser in an accident? Is it possible to predict the velocity or path of the shrapnel?
This writer recently saw a report comparing a home a/c system with R-22 refrigerant vs. the
CO2 system. The testing engineer concluded the potential energy was about the same since the R-22 system had much more volume. This report was totally misleading, as shown by the example of the bullet vs. balloon. Rather than
potential energy, we should talk of the potential for explosion and its lethalness.
Today, CO2 fire extinguishers have to be tested at 1250 psi every five years. This is an OSHA requirement. Home air conditioners need no testing. It is inconceivable to this writer that the U.S. Government will allow
CO2 a/c systems in vehicles without even more stringent requirements, like yearly pressure tests when you get your plates. Remember too, the fire extinguisher is not in a moving, vibrating environment where temperatures of -20°F to up to 300°F are possible. Not to mention the chance of collision.
Today's R-134a A/C system is usually operating at less than 1/10 of the pressures of an equivalent
CO2 system. At standstill the suction accumulator may reach 200 psi in a hot soak - a far cry from 1000 psi for
CO2 at temperatures over 86°F. If pressure testing of a mobile
CO2 system is required, how can it be done safely?
CO2: Practical Concerns. Insurance companies have recently become very risk adverse. They have recently cancelled insurance for mechanical contractors who service or install heating boilers, even those that operate at very low pressures. It is questionable whether they will even insure vehicles with A/C that use
CO2 as a refrigerant. What workman's comp rate will be imposed on shops that service these systems? Will drivers want to drive these vehicles? Will techs want to service them? Shop owners: are you ready to send your techs to “bomb squad” school?
Suppliers who want a piece of the European business should think about what they may be getting into. Bankruptcy is only a few lawsuits away. Just ask the companies making asbestos products. Automakers should also be wary of the safety issues, as they would be first in line for these
Part 2 of this series will explain the basics of GW and the “Greenhouse
Effect” and will appear in the July/August issue of Cool Profit$
Magazine. Here's the link to the subscription page for the Print version:
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