Eficiencia energética del sistema de climatización de un vehículo ferroviario: análisis paramétrico y optimización mediante técnicas DoE

Abstract

The air conditioning systems used in transport vehicles

(railway passenger cars) are constrained by two issues: the

consumed energy and the occupied space. In order to assess

how both restrictions can be fulfilled a parametric analysis

and an optimization have been carried out by means of Design

of Experiments (DoE) techniques applied to a mathematical

model of a real AC system. To evaluate the energy efficiency

of the system four parameters have been used: the COP

(Coefficient of Performance), the refrigeration power of the

system and its dimensionless expression and the effectiveness

of the evaporator. The occupied space of the AC system has

been characterized through the dimensionless volume of the

evaporator. The same compressor has been used in the analysis

and the input parameters varied have been the dimensionless

evaporator volume and four operating conditions: the

evaporator inlet air temperature and mass flow rate, the

condenser inlet air temperature and the air temperature

increment in the condenser. Through a Central Composite

Surface Response design, results show that the dimensionless

refrigeration power is the best parameter to assess the

energy efficiency because is independent of the operating

conditions and only depends on the dimensionless volume of

the evaporator: the lower the latter, the higher the former.

An optimal dimensionless volume has been identified for the

simultaneous optimization of the four output variables of the

system that provides an increase of 26% in the dimensionless

refrigeration power with respect to the baseline system.