The purpose of the course is to provide the necessary scientific and technological background as well as the necessary application and practical experience on the systems employed for central heating installations in buildings and industrial refrigeration technology. It also focuses to offer scientific knowledge and deeper understanding on the description, taxonomy and operation of various systems that are currently employed in the building industry, as well as to provide guidelines for the theoretical calculation of various heating loads in buildings in relationship to their proper thermal insulation level as imposed by the national regulations. Since the size of various components which strongly contribute the capital and operational cost of such systems are strongly determined by the heating load of buildings, the proper thermal insulation of buildings is a mandatory prerequisite that should be established before the load evaluation and the preliminary system design. Among the aims of the course is also the presentation of the mechanical refrigeration principles, systems and components such as conventional evaporator and condensing heat exchangers, centrifugal and reciprocating compressors, expansion valves and associate system components, the taxonomy and characteristics of various refrigerants, the theoretical presentation of the basic refrigeration cycles based on vapour compression, such as single stage without and with superheating and subcooling, two stage refrigeration systems of various designs etc.  The programme also covers the presentation of  the principles as well as the basic theory and calculations of the heat operated absorption systems and their comparative performance evaluation against vapour compression systems.

Course Description  

Theory: Description and taxonomy of central heating systems in buildings, historical background, recent developments, Basic thermodynamic considerations, Thermal insulation of buildings. Definition of maximum limits and evaluation of the appropriate insulation level of a building. Structure and procedures for central heating installation calculations. Basic assumptions, Load evaluation, Selection and sizing of system components. Overview of the refrigeration systems technology, Description of systems and components, Basic thermodynamic principles. The refregerants their development and characteristics, chemical structure and environmental hazards. Vapor compression refrigeration cycles, COP evaluation and performance improvement of single stage compression systems, Refrigeration cycles with overheating and subcooling. Operation with ideal compressors and compressors with ηic < 1. Two and multi stage compression refrigeration systems. Purpose, advantages and comparative performance evaluation of various two stage vapor compression systems. Absorption systems, Advantages and restrictions, Operational principles, Commonly employed absorber refrigerant mixtures, COP calculations for ordinary absorption systems, Comparative evaluation of system performance.  

Laboratory: There is a provision for the student participation in laboratory exercises during which they have the opportunity to be familiarised with the theoretical background of each exercise and to acquire practical experience with the available laboratory educational equipment, suitable for a specific group of multiple task laboratory exercises. Measurements are carried out under the supervision of laboratory staff, and are subsequently further exploited for carrying out the necessary calculations which are submitted at the end of the class for subsequent evaluation. The aim of the student participation in laboratory exercises is to offer the necessary link between theory and practice, to provide the first practical experience on the operation of heating and refrigeration systems using full size components and downscaling models of usually employed mechanical equipment and control systems. 

Expected Course Outcome

 

Bibliography

Greek: 

 

1. ΘΕΡΜΑΝΣΗ-ΨΥΞΗ-ΑΕΡΙΣΜΟΣ, Σ.Ν.Χαλικιά, Εκδοση Ο.Ε.Δ.Β., 1998 

 

English:

1. TASCHENBUCH FUR HEIZUNG UND CLIMATECHNIK Recknagel-Sprenger (Band A), Munchen, 1977
2. HEIZUNG UND KLIMATECHNIK Rietschel/ Reiss – Springer Verlag, Berlin Heidelberg und New Υork.
3. ASHRAE HANDBOOK OF FUNDAMENTALS, ASHRAE 1981
4. ASHRAE HANDBOOK OF APPLICATIONS, ASHRAE 1982