00515 - Mechanical Plants

Learning outcomes

At the end of the integrated course, students will have acquired knowledge of the principles and methods for the selection, design, and implementation of industrial plants. They will be able to analyse, size, and optimise the main types of mechanical systems by applying decision-making criteria and mathematical tools to different production systems.

At the end of this module, students will be familiar with the most common mechanical systems used in industrial applications, following the scheme below: general overview; review of the fundamental concepts required to understand their operation; analysis of their main characteristics; sizing methods; and optimisation techniques.

Course contents

PRELIMINARY CONCEPTS

• Concept of production and utility systems
• Effect of time on fixed costs: simple interest, compound interest, and present value
• Depreciation of tangible assets: straight-line economic depreciation

WATER SUPPLY AND DISTRIBUTION SYSTEMS

• Main industrial and civil uses of water
• Water supply sources (wells, public water supply systems, surface water)
• Classification of pumps (radial, axial, single-stage, multistage, etc.) and comparison among different types
• Operating ranges of different pump types
• Bernoulli's theorem and its applications to hydraulic circuits
• Pump head
• Pump power for different hydraulic circuits: open systems, closed systems with and without pressurised vessels
• Pump characteristic curve (PCC) and system characteristic curve (SCC)
• Pipes for water distribution: steel, copper, polyethylene (PE); dimensions and pressure ratings (PN)
• Valves: general classification and examples
• Distributed and local head losses in pipelines; friction factor, loss coefficients, Reynolds number, roughness, and related parameters
• Head loss charts
• Equivalent pipe length
• Hydraulic operating point
• Pumps in series and in parallel (identical and different pumps)
• Typical hydraulic system layouts
• Hydraulic pipeline sizing criteria (constant velocity, constant pressure gradient)
• Design of elevated storage tanks (24-hour demand profile, cumulative demand curve, storage volume)
• Geometry and piping layout of elevated storage tanks
• Design of hydropneumatic pressure vessels (pressure booster systems)

COMPRESSED AIR SYSTEMS

• Use of compressed air for mechanical power transmission
• Classification of compressors and overview of compressor types
• Layout of a compressed air generation plant
• Air dehumidification: shell-and-tube aftercoolers and their integration into compressed-air systems
• Humidity ratio and relative humidity; refrigeration air dryers
• Cooling capacity required for air drying
• Condensate separator: function and design
• Condensate drain: function, design, sizing, and installation layout
• Pressure regulating valve (PRV): construction, installation, and operating principle
• Chemical air dryers: adsorption and deliquescent dryers
• Psychrometric chart for compressed air and condensate calculations
• Ideal gas law (PVT) and calculation of normal volumetric flow rate
• Actual air velocity in compressed-air pipelines
• Distribution network layouts
• Pressure-loss calculations using graphical methods (nomograms)

INDUSTRIAL STEAM SYSTEMS

• Steam as a heat transfer medium
• Functional layout of an industrial steam system
• Thermodynamic cycle on the T–s diagram
• Boiler sizing: nominal and peak capacity
• Pressure reducing valve (PRV): layout and operating principle
• Design criteria for steam distribution lines
• Steam velocity in pipelines
• Condensate drainage
• Sizing of condensate return lines under start-up and steady-state conditions
• Heat exchanger sizing at the point of use
• Economic evaluation of system performance
• Bernoulli equation for calculating downstream pressure at the condensate receiver for condensate return to the hot well

FIRE PROTECTION SYSTEMS

• Overview of the main fire safety regulations for obtaining the Fire Prevention Certificate
• Combustion process: fuel, oxidiser, and heat
• Fire extinguishing methods: smothering, cooling, and fuel isolation
• Fire classes and extinguishing agents
• Standard time-temperature curve, fire load, and its relationship with temperature and time
• Fire prevention and protection; fire resistance rating (REI) and its meaning; passive and active fire protection
• Fire detection systems: applicable standards
• Types of fire detectors
• Fire water storage tank sizing
• Layout of fire pump sets according to UNI 9490
• Operating principles of fire pump units (accessories, pressure switches, start/stop controls)
• Hydrant systems: UNI 10779 standard
• Fire risk levels (1, 2, and 3)
• Hose reels and hydrants according to UNI EN 671-1 and UNI EN 671-2
• Flow coefficient (Kv) of hose reels and hydrants
• Design of branched hydrant networks: calculation of required head and actual flow rate at each hydrant
• Automatic gaseous fire extinguishing systems (ISO 14520)
• Gas extinguishing system layout and operating logic
• Main gaseous extinguishing agents, applications, and extinguishing concentrations
• Principles for calculating the required extinguishing agent quantity according to ISO 14520
• Wet, dry, and deluge sprinkler systems: overview
• UNI 9489 standard: discharge density, design area, and operating parameters
• Sprinkler system sizing according to hazard classification (Light Hazard, Ordinary Hazard, High Hazard)
• Sprinkler network layouts
• Hydraulic calculation of tree-type sprinkler systems: most hydraulically remote sprinkler (cascade calculation) and most favourable sprinkler (iterative calculation)
• Hydraulic analysis of looped sprinkler networks using the Hardy Cross method

SOLAR ENERGY SYSTEMS: PHOTOVOLTAIC SYSTEMS WITH STORAGE AND SOLAR THERMAL SYSTEMS

• Extraterrestrial solar radiation on a horizontal surface (TOA)
• Extraterrestrial solar radiation on a south-facing surface tilted by an angle β
• Components of solar radiation at ground level: global, diffuse, and direct radiation
• Empirical methods for estimating solar radiation on south-facing tilted surfaces
• Flat-plate solar collectors: types, materials, and main characteristics
• Photovoltaic modules and their main characteristics
• Battery storage systems and their performance
• Preliminary design and sizing of complete photovoltaic systems
• Solar thermal collectors
• Efficiency of flat-plate solar collectors
• Complete design and sizing of flat-plate solar thermal collector systems

Readings/Bibliography

Teaching Materials

Instructor-provided course materials

Other books

A. PARESCHI, "Impianti Industriali", Ed. Esculapio, Bologna, 2007 

G. COLI, “Impianti per il benessere e la sicurezza negli ambienti di lavoro”, PEG, Milano, 1990

S. FABBRI, “Impianti Meccanici”, Vol. I, Ed. Patron, Bologna, 1985

M. GENTILINI, ”Impianti Meccanici”, Pitagora Editrice, Bologna, 1991

A. MONTE, “Elementi di Impianti industriali”, Ed. Libreria Cortina, Torino, 1997, Voll. 1-2

O. PIERFEDERICI, “Impianti Meccanici”, Pitagora Editrice, Bologna, 1990

Teaching methods

Lectures combined with in-class numerical problem-solving sessions.

Assessment methods

Final written examination in a computer laboratory, using the Excel platform.

Office hours

See the website of Mauro Gamberi