Study of Thermal Physical Properties of Ozone-Safe Refrigerants to Validate their Introduction as Substitutes for R12 and R22
Tech Area / Field
- PHY-NGD/Fluid Mechanics and Gas Dynamics/Physics
3 Approved without Funding
St Petersburg State Academy of Refrigeration and Food Technologies, Russia, St Petersburg
- Institute of Power Engineering Problems, Belarus, Minsk, Sosny
Project summaryPurpose project and expectation results
At present, there is a critical need for data on a variety of potential halocarbon refrigerants in order to develop the best set of the substitutes of fully halogenated CFC. Purpose of the project is experimental and theoretical study of thermophysical properties of some fluorohydrocarbon ozone-safe substances and their solutions. Up to now only a few experimental thermophysical data of halocarbons refrigerants are available in the literature. Taking into account the lack of information on the properties of ozone-safe substances, experimental data obtained as a result of the project realization will let to add and improve existing information on them. Furthermore speed of sound in solutions will be measured for the first time (no data available in the literature). The development of fundamental dependencies on the basis of created database will let to prove a choice of high effective compositions in sense of perfection of thermodynamic cycle and adaptability to manufacture of refrigeration system.
Wide uses of chlorofluorocarbons (CFC) as refrigerants, blowing agents, cleaning agents, aerosols and fire estanguishant caused considerable emission of these substances into the atmosphere (stratosphere). Reaction with ultra-violet radiation, followed by release of chlorine atoms, leads to significant increase of chlorine, which then interacts with ozone and reducing thus its density in stratosphere. Since 1985, World's Community has taken various efforts on limitation and elimination of chlorofluorocarbons (CFC) and chlorofluorohydrocarbons (HCFC) production. As an alternative the fluorohydrocarbons (MFC) refrigerants and their mixtures are considered. Those compounds have no ozone deplete potential (OOP). High efficiency in sense of thermodynamic cycle perfection and quality of refrigerating machinery is rather important requirement in choice of refrigerants. The analysis shows that the decreases in efficiency represent the biggest drawbacks to the use of the pure haloginated hydrocarbons (MFC) as potentially acceptable substitutes for R12 and R22. Priorities for the binary and ternary blends of MFC are considered as the most promising working fluids to replace the fully haloginated CFC refrigerants.
The optimal selection of the a refrigerant and the designing of refrigeration system require knowledge of the thermodynamic and transport properties. The thermophysical properties needs for the haloginated hydrocarbons and their mixtures as CFC replacements in a refrigeration application are quite necessary, comparable to those for steam in power cycles.
The work on the project is supposed to be carried out in SPSARFT and IPEP NASB on high precision experimental equipment, capable to ensure study in a wide range of temperatures and pressures. During the last twenty years complex study of thermophysical properties of the ozone-safe refrigerants and their mixtures is carried out. Results of these researches were published in 70 articles, including the Proceedings of the International thermophysical and refrigeration Symposiums. The comparison with literature has shown good correlation with a modern level of experimental methods and correlation of results. Scientific leader O.B. Tsvetkov is the author of three monographs on the properties of refrigerants. In those monographs he has given the need for and uses of thermodynamic and transport properties in the selection of environmentally acceptable working fluids in the refrigeration, air-conditioning and heat-pumping equipment. The works gained great interest of the experts.
Experimental methods and proposed mathematical models were examined on the number of substances: nitrogen dioxide solutions, hydrazine, solutions of oxidizers in a strong nitric acid and various refrigerants. Some members of the project scientific staff are involved in working group on the transport properties of technically important substances in International Union on Pure and Applied Chemistry (IUPAC).
The proposed project provides a search and feasibility study of alternative for R12 and R22 refrigerants.
Key objectives of the given research -oriented project are:
a) the ozone-safe refrigerants: R32, R125, R134a, R152a;
b) binary blends: R134a - R152a, R32 - R125, R32 - R134a and R125 -R134a.
A number of independent but interconnected problems are proposed in this project:
- pressure-volume-temperature (P-V-T) measurements;
- liquid and gas density measurements;
- liquid speed of sound measurements;
- thermal conductivity measurements for the gaseous and liquid states;
- presentation of measurement results and theoretically based computer models for correlation and prediction of thermophysical properties of pure refrigerants and their blends.
As a result of the project the following data will be reported:
1) experimental data on thermophysical properties of inpidual refrigerants and their binary mixtures;
2) theoretical models, which approximate reported in the project and literature experimental data.
The work in frame of the project will be completed by issue of the final scientific report and publications, included the whole file of received experimental data, as well as theoretical models on investigated binary mixtures thermophysical properties.
Potential role foreign colloquies
As a foreign collaborators of the project are invited R&D community, industry-oriented companies, experts from USA, EC, Japan, Sweden, Finland, Norway and everyone who will show professional interest to this proposal. Key objectives of the foreign collaborators ere:
- discussion of the central focuses of the research project, together with on overview of the key results expected after the completion of the project; to the solution of industrial and environment security - related problems;
- ability to disseminate the received information for foreign users and as an gateway to other thermophysical properties of refrigerants databases;
- coinvestigation by the various laboratories in the world of the same refrigerants sample for the comparison of the quality of the experimental instruments, techniques and correlations;
- to promote the participation of the scientists in the international meetings (conferences, working groups, seminars) where the issues in frame of the project will be discussed.