Ecological purposefulness of the use

Resolutions of the Montreal Protocol have fundamentally changed the approach to traditional ozone-destroying refrigerants, and since 90-ies the problem of danger of climate fluctuation and preservation of greenhouse gas emission caused by the use of these refrigerants, has come first.

As to the extent of ozone-destroying activity of the Earth's ozone layer, haloid-producing hydrocarbons are divided into three groups:

• Refrigerants with high ozone-destroying activity - these are chlorine fluorocarbons (CFC) R11, R12, R13, R113, R114, R115, R502, R503, R12B1, R13B1 (or according to International designation CFC11, CFC12, CFC13 etc.) and others;
• Refrigerants with low ozone-destroying activity - these are hydro chlorine fluorocarbons (HCFC) R21, R22, R141b, R142b, R123, R124 (or according to International designation HCFC21, HCFC22, HCFC141b etc.) and others, whose molecules contain hydrogen. These substances are characterized by less time of being in the atmosphere compared to CFC, and as a result, they have less affect on destroying of ozone layer. A number of multi-component actuating fluids suggested as alternatives to CFC contain HCFC as one of the components, for example, R22;
• Refrigerants with no contain of chlorine atoms [fluorocarbons (FC), hydrofluorocarbons (HFC), hydrocarbon and others], are considered to be absolutely ozone-safe. These are such refrigerants as R134, R134a, R152a, R143a, R125, R32, R23, R218, R116, RC318, R290, R600, R600a, R717 and others.

As an alternative to production-prohibited refrigerants, the Montreal Protocol is considering the following classes of substances:

• Hydro chlorine fluorocarbons (HCFC);
• Hydrofluorocarbons (HFC);
• Natural refrigerants - ammonia, carbon dioxide, water, hydrocarbons.

The Protocol has come into force since January 12, 1989. 150 states have joined it (1995). In June of 1990, on the conference in London there was taken a decision to stop using of all kinds of freons by industrially developed countries by 2000.

The Montreal Protocol has established active economic constraints not only for production and use of CFC, but also for distribution, export and import of any refrigerating equipment containing CFC. Home government control is one more powerful driving force to reject ozone-destroying refrigerants. Thus, in EU countries production of CFC has been stopped since January 1, 1995. In a number of countries, for example, the USA, a consumer while buying CFC is obliged to pay government tax exceeding the cost of the refrigerant itself.

It is well known that the continuous use of CFC during a year is equivalent, as to the influence on the environment, to 10:50 years of the use of such alternative refrigerants as HCFC.

On the International meeting in Copenhagen (November 1992), participants of the Montreal Protocol have taken a decision to stop production of ozone-dangerous refrigerants Rll, R12 and R502 since January 1, 1996. On January 1, 1994, production of CFC contextures constituted only 25% compared to production of 1989. The former USSR has signed the Montreal Protocol, and in 1991 Russia, Ukraine and Byelorussia confirmed their succession of this decision.

Active date of the substance use restriction accepted on the Vienna Conference in 1995, are given in the table:

* Countries-participants of the Montreal Protocol produced 80% of the world quantity of CFC in 1987.

A number of the European states outrun established dates. Thus, Sweden has prohibited HCFC use in the new equipment since January 1, 1998, and servicing of serial equipment - since January 1, 2002, Denmark - since January 1, correspondingly 2000 and 2002. In Italy it was a legislative act prohibiting production, import and export of HCFC since December 31, 1999; products with HCFC have to be specially stamped and be necessarily returned to the supplier at the end of their operation period. Germany is intended to prohibit HCFC use in the new refrigerating equipment since 2000, Switzerland - since 2005. The USA are planning to reject R141b since 2003, R22 - since 2010, R123 - since 2020.

In Russia, a number of resolutions of the Russian Federation government are effective on this point, in particular, the resolution of the RF government dated May 24, 1995, No 526 "About immediate measures to fulfill the Vienna Convention on protection of ozone layer and the Montreal Protocol on substances destroying ozone layer" containing the program of industry going over to production and use of ozone-safe substances grounded on generally accepted principles. However, it didn't obtain the status of national program and, thus, it's not being financed and fulfilled. Out of all the program resolutions only one of them is effective - prohibiting.

The resolution of the Russian Federation government No 563 "About regulation of import to the Russian Federation and export from the Russian Federation of ozone-destroying substances and products containing them" prohibits export of ozone-destroying substances (ODS) and products containing them to the countries, which haven't signed the Montreal Protocol. Many of CIS countries are included, in particular (Kazakhstan, Azerbaijan, Kirgizia and others) where Russia traditionally used to export ozone-destroying substances, refrigerating equipment and other products containing these substances.

By the moment of the Montreal Protocol acceptance, Russia was among the biggest world producers and consumers of ozone-destroying substances. The peak of their production in Russia was in 1990 and constituted 20% of the world level. Fulfilling undertaken obligations according to international agreements, Russia is steadily reducing the volume of CFC production. Thus, in 1996, the volume of CFC production constituted 17122 tons compared to their production of 110 140 tons in 1990. According to the resolution of special Interdepartmental commission on protection of ozone layer, there was prepared a schedule of step-by-step CFC renunciation: in 1998 - 4500 tons, in 1999 - 2800 tons and in 2000 - since 01.07 absolute cessation of CFC production on the territory of Russia (resolution ь 490 of Government of the RF dated 1999).

To analyze ecologic purposefulness of the use of refrigerants, the following parameters are used: Ozone Depletion Potential ODP; Global Warming Potential (Greenhouse Effect) GWP or HGWP (Halocarlon Global Warming Potential).

Ozone Depletion Potential ODP is defined by availability of chlorine atoms in a molecule of the refrigerant and is taken as a unit for R11 and R12. For the refrigerants of CFC group, ozone Depletion Potential ODP > or = 1, for HCFC ODP < 0,1, and for HFC ODP = 0.

Global Warming Potential GWP is taken as a unit for carbon dioxide (CO₂) with temporary horizon of 100 years, and potential HGWP is calculated with regard to value of this parameter for R11, taken as a unit as well.

According to international prognosis, with the existing rate of growth of greenhouse effect, the average temperature of the Earth's atmosphere can be 3:5 K higher by 2050 and it can cause increasing of the World Ocean level by 20 sm and, thus, lead to irreversible ecologic consequences.

It is known that haloid-producing hydrocarbons have much bigger global warming potential GWP than carbon dioxide. However, the quantity of carbon dioxide hitting the atmosphere considerably exceeds the volume of leaking of haloid-producing hydrocarbons, and that's why, direct influence of the latter on increasing of greenhouse effect was considered to be insignificant before. Let's consider this aspect in more details.

The value of greenhouse effect is proportionate to quantity of carbon dioxide contained in the Earth's atmosphere. On the industrial enterprises of the world, more than 15 * 10⁹ tons of standard coal is burnt each year, which causes release of 16,5 * 10⁹ of carbon dioxide into the atmosphere. Considerable part of carbon dioxide hitting the atmosphere is evolved on thermal stations while burning boiler oil, gas and coal. This quantity, according to different estimations, is (2,2...7,2) * 10⁹ tons/year. Mass of polyhlorvinyls and refrigerants each year produced by the chemical industry is 2*10⁴ tons/year, which, according to reappraisal through GWR averaged coefficient, corresponds to the quantity of carbon dioxide of 4,3*10⁹ tons/year. Only 20...25 % of emission of yearly produced refrigerants is equivalent to carbon dioxide contribution to greenhouse effect which is (5,1...5,5)*10⁶ tons/year. Contribution of different gases into greenhouse effect (%) is given below.

As it can be seen from these data, the most considerable portion in the Earth's atmosphere is that of carbon dioxide which, according to the international sources of information, can reach 81%. Even if it turned out well to stabilize CO₂ emission on the level of 1994, the portion of carbon dioxide in the atmosphere could have become twice as bigger as it was before the era of industrial development (since 1750) by 2100.

Carbon dioxide emission [kg/(kWt*hour)] at electricity production in a number of industrially developed countries is given below.

In its turn, carbon dioxide emission [kg/(kWt*h)] at electricity production depends on many factors, first of all, on the basic material being used.

Loss of electric power is also important while its transfer to the consumer.

Recently, in order to analyze total potential of greenhouse effect with taking into consideration both energetic and ecological factors, more and more there is used a parameter called Total Equivalent Warming Impact TEWI. The technique of TEWI calculation was developed by the International institute of the cold. TEWI parameter for a concrete substance is the sum of direct potential of greenhouse effect as a result of this substance emission into the atmosphere and indirect potential conditioned by carbon dioxide emission in the process of electricity production necessary for operation of refrigerating facilities:

where GWP - global warming potential; M - mass of refrigerant emission into the atmosphere; a - coefficient characterizing carbon dioxide emission into the Earth's atmosphere with electric power output of 1 kWt*h; B - quantity of electric power consumed for the whole period of operation of a concrete refrigerating facility; L - period of operation of the equipment.

At production of electric power by hydroelectric power plants, wind engines and nuclear power plants, emission of carbon dioxide into the atmosphere does not occur (coefficient a is zero), while at production of electric power by thermal power plants, carbon dioxide is released into the atmosphere. According to the Center of thermocompressors of International power agency in 1992, at production of 1 kWt/h of electricity in Europe carbon dioxide emission constituted at the average 0.52 kg (and in a number of countries twice as much as average value), in the North America - 0.67 kg. Service life of a refrigerating facility can reach 15:20 years, that's why, the second component reflecting indirect influence is becoming predominant in total evaluation, reaching 0,95...0,98 TEWI.

In Norway, for example, 99,6 % of total electricity is produced on hydroelectric power plants, that's why, carbon dioxide emission constitutes at the average 0,005 kg for 1 kWt*h. At the same time, in Denmark 91 % of electric power is produced while burning of coal which causes emission of 1.1 kg of carbon dioxide for 1 kWt*h of energy.

According to prognosis of the Institute on problems of safe development of nuclear power, possible total thermal influence of CFC and their substitutes on the Earth's climate will not exceed 10 % of the value of total radiation forcing. The definition of radiation forcing is changing of denseness of radiant heat flux on the outer boundary of troposphere compared to the initial one (in pre-industrial era - before 1880). According to estimation of the Italian department of the Green Peace, contribution of CFC only into greenhouse effect will constitute in future more that 13%, and according to other data, contribution of CFC will exceed 20%.

The UNO conference on the questions of environment and development in Rio de Janeiro proclaimed the Framework Convention on Climate Fluctuation. Convention have been signed by more than 160 states, tens of states have already ratified it. The USA proclaimed in April of 1994 about national obligation to reduce by 2000 the release of greenhouse gases to the level of 1990. The Convention requires the same from all industrially developed countries.

Resolutions of the Convention accepted in 1997 in Kyoto (Japan) restrict release of greenhouse gases even more.

Norway has introduced special tax on release of carbon dioxide since 1991. In the near future the same has to be done by the countries whose parliaments have ratified the Framework Convention.

According to the evaluation of foreign specialists, the level of safe emission of carbon dioxide is 1.1 tons per capita. At the moment, the level of emission of carbon dioxide per capita in Europe is 7.3 tons per year.