Approaching the validation of building energy models: billing vs indoor environmental data

Domenico Palladino,Iole Nardi

doi:10.1051/e3sconf/202019702001

Abstract

To understand the real building energy consumption, and to identify the best energy improvements (due to energy refurbishment and/or HVAC replacement), the energy audit is recommended, but it generally entails the realization of an energy model of the building itself. The main issue of this approach is the collection of data, needed to verify the reliability of the energy audit results. Currently, to validate buildings energy model retrieved by hourly semi-stationary software, is it possible to refer to: (i) bills related to energy carrier (i.e. natural gas and/or electricity); (ii) monitored indoor parameters. The aim of the paper is to understand which of the two is more suitable for the purpose. In this work, the two options are investigated considering, as case study, a family house located in central Italy, whose envelope thermophysical properties and HVAC systems are known, and whose bills and indoor environmental conditions (air temperature and relative humidity) were archived since December 2019. Results from the two validation methods are very close to each other; particularly, results show that energy audit performed with indoor environmental parameters better fits the real consumption, but it entails more complex validation procedure.

Highlights

Energy audit is a useful tool allowing to identify the real energy consumption of buildings and to find solutions able to improve its energy efficiency [1,2]
The methodology to be adopted for an energy audit is ruled by [4,5], which provides a validation methodology of model based on energy carrier bills
3.1 Energy Audit A - billing The validation criterion of energy audit A is based on the comparison between simulated and billed natural gas consumption for the heating purpose (H)

Summary

Introduction

Energy audit is a useful tool allowing to identify the real energy consumption of buildings and to find solutions able to improve its energy efficiency [1,2]. For the residential and buildings sector, instead, energy audit is mandatory only to access economic incentives. The methodology to be adopted for an energy audit is ruled by [4,5], which provides a validation methodology of model based on energy carrier bills. The most common method is the validation by comparing the monitored indoor environmental conditions with simulated ones, such as in [8,9]. It is possible to refer to: (i) bills related to the energy carrier (i.e. natural gas and electricity); (ii) monitored indoor parameters. An existing and occupied residential building was chosen as case study, and it was investigated by applying both energy audit approaches using a commercial and certificated software. The case study has been investigated since 2019 by acquiring both billing and indoor environmental conditions

Objectives

Methods

Results

Conclusion