Improving Building Energy Efficiency through Measurement of Building Physics Properties Using Dynamic Heating Tests

Ljubomir Jankovic

doi:10.3390/en12081450

Abstract

Buildings contribute to nearly 30% of global carbon dioxide emissions, making a significant impact on climate change. Despite advanced design methods, such as those based on dynamic simulation tools, a significant discrepancy exists between designed and actual performance. This so-called performance gap occurs as a result of many factors, including the discrepancies between theoretical properties of building materials and properties of the same materials in buildings in use, reflected in the physics properties of the entire building. There are several different ways in which building physics properties and the underlying properties of materials can be established: a co-heating test, which measures the overall heat loss coefficient of the building; a dynamic heating test, which, in addition to the overall heat loss coefficient, also measures the effective thermal capacitance and the time constant of the building; and a simulation of the dynamic heating test with a calibrated simulation model, which establishes the same three properties in a non-disruptive way in comparison with the actual physical tests. This article introduces a method of measuring building physics properties through actual and simulated dynamic heating tests. It gives insights into the properties of building materials in use and it documents significant discrepancies between theoretical and measured properties. It introduces a quality assurance method for building construction and retrofit projects, and it explains the application of results on energy efficiency improvements in building design and control. It calls for re-examination of material properties data and for increased safety margins in order to make significant improvements in building energy efficiency.

Highlights

According to a Global Status Report 2017 [1], buildings account for 28% of global carbon dioxide emissions, and are a significant contributor to climate change
The method in this research consists of two parts: physical dynamic heating tests in a building, and the calibration of a dynamic simulation model of the building before and after the retrofit and carrying out dynamic heating test simulations with the calibrated models
This was attributed to an internal limit in the EnergyPlus model that could not be found, and it was decided to limit the analysis of simulated dynamic heating tests in this article to 3, 6, and 9 kW inputs

Summary

Introduction

According to a Global Status Report 2017 [1], buildings account for 28% of global carbon dioxide emissions, and are a significant contributor to climate change. A recently published report by the Intergovernmental Panel on Climate Change [2] stresses the need for urgent action to reduce global carbon emissions, and intervention on buildings needs to form a significant part of this effort. It is critical to establish thermal properties of an existing building accurately in order to be able to design performance improvements with confidence. There are two types of physical tests that can be carried out on a building that enable thermal properties to be determined: a co-heating test [3], p. The former involves heating a building with supplementary electric heaters over a period of several days, as well as monitoring internal and external air temperatures and the Energies 2019, 12, 1450; doi:10.3390/en12081450 www.mdpi.com/journal/energies

Methods

Discussion

Conclusion