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Theses

Analysis and simulation of defects of operation for air conditioning audit

Abstract : Nowadays air conditioning is a significant energy stake because of its frequent use in new buildings (also strengthened by global warming) and of the European stock already important. The Directive on Energy Performance of Buildings wants to improve the air conditioning performance through the regular inspection for systems over 12 kW. The inspection aims to assess how the system works and then to propose measures for improvement. While for heating audit methods exist since many years, methods for air conditioning are rare, sometimes derived from those for heating and not optimised. The thesis wants to identify and quantify the problems that air conditioning systems meet all along their lifetime from a technical standpoint. The question is how to detect the operation problems and what are their energy impacts and effects on comfort. The air conditioning technologies are many and change depending on the building type and specific needs. Two types of systems have been analysed, the most common on the European market: the split air conditioners and chillers. The characteristics of the chosen systems are representative of system widely present in the stock. The most common defects for these two types of system have been taken as a base. Different methods of analysis were applied. Firstly, a method of qualitative analysis of defects by a schematic representation of tree defects. This enabled us to better understand the physics of each defect. Then a quantitative method of modelling at fixed temperature conditions allowed us to define the parameters and measurable effects on performance. In order to be closer to reality, the systems have been modelled in variable conditions. The model takes into account part-load operation of the system and can quantify the effects in terms of seasonal consumption and impact on comfort in cases of French typical buildings placed in climates of reference. Finally, a temporal method links the level of the defect to the operation time in order to observe the gradual deterioration and to determine the optimal frequency of corrective action in terms of energy and cost. We could thus obtain a multi-year performance curve with or without corrective or preventive action. Modelling is the main tool of this thesis because of its flexible and efficiency to isolate the effect of degradation of each defect. Moreover, the studied problem is a case where the experimental verification is long and where the various effects interfere with each other. All the experimental elements identified in the literature were used to validate the results and to set some models.
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Submitted on : Wednesday, November 19, 2008 - 8:00:00 AM
Last modification on : Wednesday, October 14, 2020 - 4:02:37 AM
Long-term archiving on: : Friday, September 10, 2010 - 12:52:36 PM

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  • HAL Id : pastel-00004297, version 1

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Daniela Bory. Analysis and simulation of defects of operation for air conditioning audit. Engineering Sciences [physics]. École Nationale Supérieure des Mines de Paris, 2008. English. ⟨NNT : 2008ENMP1577⟩. ⟨pastel-00004297⟩

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