Comparison process

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Comparison process is a term from technical thermodynamics .

In contrast to the Carnot process known in physics , which - regardless of technically feasible machines or systems - the optimum conversion of heat into mechanical energy with given heat sources (e.g. hot flue gas) and sinks (mostly the environment) describes, comparison processes are thermodynamic cycle processes that are tailored to special machines and systems. They indicate the optimum that can be achieved with these machines in the ideal case, i.e. H. can be achieved with smooth (more general dissipation-free ) changes in state .

This also includes the heat transfer on the inside to the working medium (usually gas or steam). These processes are therefore also referred to as internally reversible . The quality of the actually achievable processes is referred to as the quality level. It is the quotient of the thermal efficiency of the real machine to that of the ideal machine.

Significant comparison processes

Significant comparison processes are:

• Diesel process as a constant pressure process
• Otto process as an equal space process
• Seiliger process in general for internal combustion engines
• Joule process for single-stage gas turbine systems
• Ericsson process for multi-stage gas turbine plants
• Clausius-Rankine process for single-stage steam power plants
• Stirling process for the Stirling engine
• Plank cycle - chillers / heat pumps
• Kalina cycle
• Lenoir cycle

Calculation of the comparison processes for the working material: Ideal gas with constant heat capacity

A large number of comparison processes are made up of reversible, quasi-steady state changes (isotherms, isobars, isochores, isentropes, polytropes) and are therefore relatively easy to calculate. Repetitive calculations are required to optimize parameters, for which detailed algorithms and calculation programs are used:

literature

• Literature on technical thermodynamics

See also

Thermodynamic System , Second Law , Entropy (Thermodynamics) , Adiabatic Machine , Technical Work

Web links

• Uni Duisburg-Essen, basics of technical thermodynamics with exercises

Individual evidence

1. ↑ Bernd Glück: “Reversible state changes of the ideal gas” . Algorithms and computer program with graphic representation of the state progression