Abstract

In the last years, international technical standards have introduced several procedures for modelling the heat generation sub-system, both providing new calculation methods and updating the old ones. A still open issue concerns the modelling of these sub-systems, by adapting the standard procedure – usually founded on simplified assumptions – to the structure of a detailed dynamic simulation tool. In this paper, the main procedures introduced by the international technical standards issued under the Mandate M/480 EN of 2010 on the heat generation sub-systems are presented, with a focus on combustion systems, chillers, and heat pumps. Simplifications and assumptions are analysed, by pointing out the limits related to the simplified modelling based on empirical correlations and tabulated values. The heat generation standardised models are compared with the ones used in detailed simulation tools, such as EnergyPlus. The main differences in the input data and in the model options are presented, and advices for the completion of the information commonly found in technical data sheets are provided. The paper is aimed both at promoting an effective application of the standards in the building design field and at contributing to the standardisation activity for the achievement of more accurate calculation models.

Highlights

  • Some analyses were focused on the withdrawn standards of the previous Mandate [3], as for instance the study of Mattarelli et al [4], who investigated the variation of the output results caused by the use of default values in place of the real product ones for the generation subsystems

  • The new standard procedures are part of a wider group of calculation models commonly applied for the assessment of the building energy performance; they include both the simplified calculation methods – usually employed in the standards – and more complex ones, commonly used in detailed simulation software

  • The calculation methods to assess the heat losses and the energy input of the main generation subsystems – such as boiler, heat pump and chiller – are analysed, deepening the main structure of the calculation procedure provided by the technical standards and the simulation software

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Summary

Introduction

The present work has the purpose to analyse the main procedures provided by the recently issued technical standards and focused on the generation subsystem, deepening their different level of complexity in both modelling aspects and detail of input data. The analysis of the input data is performed as to identify the main differences between the methods; difficulties that may occur in case of an excessively detailed input request are discussed (Section 3). In case this latter condition happens, some advices for the fulfilment of the method requirements are suggested (Section 4)

Standardization framework
Analysis of the calculation methods
Simplified method (International standard procedure)
Detailed methods (EnergyPlus procedure)
Detailed methods (TRNSYS procedure)
Simplified method (alternative procedure)
Detailed methods (EnergyPlus)
Input comparison: boiler
Input comparison: heat pump
Input comparison: chiller
Advices for the completion of the information
Conclusions

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