Sustainability of HVAC systems in rolling stock

Student: Arno Kok

Company: Nedtrain

Supervisors: F.J.A.M. van Houten, dr. Ir. S. Hoekstra, L.A.M. van Dongen, ir. F.G.M. Kokkeler, ir. B. Huisman

Research scope

The objective of this study is to provide NedTrain with an evaluation method of alternative HVAC (Heating Ventilation Air Conditioning)-system-designs based on relevant sustainability aspects in order to support the decision making process when regarding rolling stock modernization.

In order to methodically compare different HVAC systems on sustainability, given a certain usage profile, a tool has been designed. This tool is useful during specification and design of a railway coach by, for example, a system integrator. By giving a specific usage profile as input, as well as the HVAC specifications, the designed model gives an estimation of the yearly power consumption. Based on this yearly power consumption it is possible to choose a system that is sustainable, cost efficient and based on specific operational parameters, for example coach type, local weather conditions and coach usage.

Research motivation

Sustainability becomes more and more of an issue not only in daily life, but also within companies like the NS. Currently decisions are still made based mainly on financial aspects, when new rolling stock is purchased or old coaches are being prepared for modernization, as with most companies. NS has embraced social responsible business practices and sustainability is one of the core issues for the coming years. It is thus necessary that sustainability becomes more and more key in its decision making process. In order to smooth this integration, of sustainability into the decision making process, a method needs to be developed.

Study approach

Several core indicators to measure sustainability have been defined in order to integrate sustainability into design decisions. Unfortunately, some of these indicators remain on an abstract level and are therefore hard to measure and thus to implement. Combined with a limited time frame this study has focused on energy efficiency; this indicator can be measured and implemented without difficulty.

Study outcomes
A model has been proposed in order to assess the energy consumption of a HVAC-system design. A simulation tool has been built using MS Excel which can simulate the yearly energy consumption of a railway coach. This model has been partially verified with operational data of several trains from the VIRM fleet. Furthermore the model has been compared to the current models used by the industry.