Search Results

The development of Electrical and Hybrid cars led to the introduction of reversible heat pump systems in order to reduce the energy consumption and increase the car autonomy during the Zero Emission Mode. One of the most important components in the heat pump system, is the evaporator condenser that “pumps the heat” from the ambient air. Moreover, this heat exchanger has to work in both modes: A/C (condenser mode) and heat pump (evaporator mode). This paper will explain the main steps of the development of this heat exchanger: circuiting (refrigerant side) in order to improve the homogeneity and the performances fins (air side) in order to reduce icing impact. We will also present system tests results that illustrate the impact of those evolutions on loop performances (heating capacity and COP).

Electrical Air Conditioning Systems for 42 V vehicles will provide many benefits in terms of Environment protection, car Architecture, cabin Comfort and overall Safety. E-A/C Systems essentially differ from conventional ones by the use of electrical compressors. First of all, they will be particularly well adapted to new powertrains, helping to make them more environmentally friendly. Accurate control and high efficiency under the most common thermal conditions will reduce the A/C impact on fuel consumption. Besides, higher sealing integrity will cut emissions of refrigerant during normal operation and maintenance. Secondly, the use of an electrically driven compressor (EDC) will suppress a belt, and will reduce the packaging constraints. This will help to design new vehicle architectures. Thirdly, the electrification of air conditioning will allow better thermal comfort. In particular, E-A/C Systems provide a good opportunity for cabin pre-conditioning.

From the end of 1997, Kyoto Protocol has forced system engineers to look more about their system green house contribution. In this paper, we use Total Equivalent Warming Impact analysis to understand what are the key issues between various A/C systems possible for the future. Estimation of TEWI is done using experimental data but also precise simulation results when available. A/C systems using refrigerant HFC R134a and C02 R744 are taken into account but also system based on electric compressor due to the possible change in automotive engine technology to hybrid and fuel cells. Two major topics are considered: the first one is relative to acceptable leakage of refrigerant and the second one is the control of the A/C system around optimal conditions in respect with the fuel consumption.

The purpose of this study is to develop and to validate the techniques required to perform computational analysis of windshield defogging problem. A numerical model of a simplified test vehicle configuration has been built, which includes the passenger compartment, the windshield and the film of the condensed vapor layer. A transient analysis is performed for the conditions in which cold room test data is available. The results of numerical simulation show very reasonable agreement with the test data.

Providing adequate level of comfort is the main objective of an HVAC. This kind of information is not very useful at the end of a study and also is very expensive to obtain if only an experimental approach is used. In fact, the analysis of comfort problem is the right place for a model. The paper will concern the development of a in cab thermal comfort numerical model. The first part of the development is only achieved for the winter outside conditions. The model is developed in order to predict the local thermal sensations of the car driver according to the thermal conditions provided by the heating system. A lot of experiments have been lead in the VALEO wind tunnel to complete and validate the model. The development perspectives concern the summer outside conditions. This study supported by VALEO Climate Control and PSA PEUGEOT CITROEN, has been performed by the Laboratory LESETH (University of Toulouse).