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Contribution to elaboration of the combined automated installation for cooling of milk with application of natural and artificial cold

Author: Creţu Victor
Degree:doctor of engineering
Speciality: 05.20.02 - Electrification and Automation of Agriculture
Scientific adviser: Liviu Volconovici
doctor habilitat, professor, Agrarian State University of Moldova
Institution: Agrarian State University of Moldova
Scientific council: D 60-05.20.02-25.12.03
Agrarian State University of Moldova


The thesis was presented on the 23 November, 2010
Approved by NCAA on the 24 February, 2011


Adobe PDF document13.16 Mb / in romanian


Use of electrical energy; reliability systems, process of milk cooling, accumulator of natural cold, the vacuum installation of cooling, the mathematical model.


Thesis contains introduction, four chapters, general conclusions, 146 bibliographical titles, appendixes, 139 pages of basic text, including 38 figures and 17 tables. Results have been published in 23 scientific articles, including 4 articles as sole author, 2 articles in referenced journals and one patent of invention.

Area of study Area of study refers to the development of ecological installation for cooling of milk with the application of natural and artificial cold.

The purpose of work: to execute the researches in the given area and provide assistance in development and implementation of the installation for cooling of milk with application of a natural and artificial cold for Republic of Moldova.

Objectives: the performing of a study of traditional and ecological installations; – research the ecological refrigerating installation for cooling of milk with low energy consumption ; – system engineering of management of the technological process for cooling milk with low energy consumption; – realization of experimental and technical and economic research for ecological installations with low energy consumption for cooling milk and improvement of technical and economic methods in autoimmunization of technological processes in agrarian sector.

Scientific novelty and originality:

were proved the efficiency of using the accumulator of natural cold with vacuum installation for reduction the electrical energy consumption for cooling of milk; a mathematical model was developed that allows to assess the constructive-technological parameters of installations with vacuum evaporation and of accumulators with natural cold and their dependence on environmental parameters ( temperatures of atmospheric air and water, period of year, etc.); the method was developed and are received the analytical data for definition of parameters of ecological refrigerating systems for cooling of milk; has been improved the method of techno-economic calculation which enables complex analysis of efficiency of bio-technique system for cooling milk, under the influence of factors of production and market; scientific novelty is confirmed by the patent of invention (MD nr.F25D3/02) about the accumulator of natural cold for cooling of milk.

Theoretical significance and applied value of work: investigations related to accumulator of natural o cold with vacuum installation can be used in the practical application in order to save electricity and increase their competitiveness with refrigeration installations for cooling of milk with compressor; the mathematical model developed enables assessment the constructive and technological parameters of accumulators with natural cold and vacuum installations, as well as determine their dependence on environmental parameters; on the basis of results of theoretical and experimental researches of the technological process of cooling of milk with vacuum evaporation were determined the curves for process of cooling of milk. Was proved the system efficiency at the using the cooling of the consecutive portions of milk; the offered method of an estimation of the technical and economic decisions in the field of automation of processes for cooling milk, enables to do the complex analysis about operating efficiency of the system in case of the variable factors of production and market.

Practical use of scientific results The results of work were included in 2004 into the educational plans of State Agrarian University of Moldova in two disciplines:
– Automation of technological processes in agriculture;
– Designing systems of electrification of agriculture.

The given researches were used in methodical preparation of the project “Designing of systems of electrification of an agriculture” at State Agrarian University of Moldova in 2005, and also, for development of the educational program at discipline " Renewed sources of energy " and methodical instructions(indications) on technical and economic account of the automated processes of agriculture in 2006 and were used at designing of co-generation installation on sewage treatment station in Kishinev during 2003-2005 years.