The optimal intercooling of compressors by a finite number of interooolers

Intercooling of compressors is necessary for an efficient process. Among the optimal criteria required, minimizing the compression-specific work is one of the more commonly used. Upon ideal conditions, such a criterion leads to an isothermal compression whose importance is purely theoretical, since it requires an infinite number of intercoolers. In this paper the evaluation of correction factors to the well-known relations of the optimal location of intercoolers in a compression process and its corresponding work of compression was performed for a general compression process which accounts for pressure losses and other irreversibilities as well. As a result of including the pressure losses in the equations, a finite number of intercoolers is evaluated as optimum. The results, although qualitatively expected, show a quantitative nonempirical figure of the optimal number of intercoolers as a function of the terminal pressure ratio and as a function of the relative pressure losses. The ideal conditions are evaluated and verified as a particular case by assuming no pressure losses. In practice, these results can be used as an upper limit for technoeconomical optimization processes.