Measured and Simulated Energy Use in a Secondary School Building in Sweden—A Case Study of Validation, Airing, and Occupancy Behaviour

Jessika Steen Englund,Mathias Cehlin,Bahram Moshfegh,Jan Akander

doi:10.3390/en13092325

Jessika Steen Englund, Mathias Cehlin + Show 2 more

Open Access

https://doi.org/10.3390/en13092325

Copy DOI

Journal: Energies	Publication Date: May 7, 2020
Citations: 19	License type: CC BY 4.0

Affiliation: University of Gävle, Linköping University

Abstract

In this case study, the energy performance of a secondary school building from the 1960s in Gävle, Sweden, was modelled in the building energy simulation (BES) tool IDA ICE version 4.8 prior to major renovation planning. The objectives of the study were to validate the BES model during both occupied and unoccupied periods, investigate how to model airing and varying occupancy behaviour, and finally investigate energy use to identify potential energy-efficiency measures. The BES model was validated by using field measurements and evidence-based input. Thermal bridges, infiltration, mechanical ventilation, domestic hot water circulation losses, and space heating power were calculated and measured. A backcasting method was developed to model heat losses due to airing, opening windows and doors, and other occupancy behaviour through regression analysis between daily heat power and outdoor temperature. Validation results show good agreement: 3.4% discrepancy between space heating measurements and simulations during an unoccupied week. Corresponding monthly discrepancy varied between 5.5% and 10.6% during three months with occupants. Annual simulation indicates that the best potential renovation measures are changing to efficient windows, improved envelope airtightness, new controls of the HVAC system, and increased external wall thermal insulation.

Highlights

Residential and public buildings account for around 40% of the annual energy use and 36% of greenhouse gas emissions in Europe [1,2]
Research process to build and validate the building energy simulation (BES) model is shown in Figure 2, and it can be divided into five main steps
Results from unoccupied and occupied validation periods, how to handle airing and varying occupant behaviour, annual heat balance simulation, and potential energy efficiency measures in renovation planning are presented in this chapter

Summary

Introduction

Residential and public buildings account for around 40% of the annual energy use and 36% of greenhouse gas emissions in Europe [1,2]. The increase in energy use by heating, ventilation, and air conditioning systems is significant, with a share of about 50% of the buildings’ total energy use and around 15% of a nation’s energy use [2]. Reductions in energy demand and efficient energy use are seen as feasible ways for more sustainable energy use in the built environment. In the European Union (EU), policies for energy efficiency in buildings have been stricter according to the EU2030 goals to meet the EU’s long-term 2050 greenhouse gas reductions target [3].

Objectives

Methods

Results

Conclusion