Development of a Reduced Order Model of Solar Heat Gains Prediction

Meril Tamm,Joan Farnós Baulenas,Roser Capdevila Paramio,Martin Thalfeldt,Jordi Macià Cid,Jarek Kurnitski

doi:10.3390/en13236316

Abstract

The aim of this study was to elaborate and validate a reduced order model able to forecast solar heat gains as a function of the architectural parameters that determine the solar heat gains. The study focused on office buildings in Catalonia and Spain and their physical values were taken from the Spanish Building Technical Code and European Union Directive 2018/844. A reduced order model with three direct variables (solar heat gain coefficient, shade factor, window to wall ratio) and one indirect design variable (building orientation) was obtained and validated in respect to the International Performance Measurement and Verification Protocol. Building envelope properties were fixed and the values were taken from the national standards of Spain. This work validates solar heat gain coefficient as a primary variable in determining the annual solar heat gains in a building. Further work of developed model could result in building energy need quick evaluation tool in terms of solar heat gains for architects in building early stage as it has an advantage over detailed building simulation programs in terms of instant calculation and the limited need for predefined input data.

Highlights

Solar energy is the largest untapped energy source, which used in a smart way can result in great active and passive energy savings in building sector
Further work of developed model could result in building energy need quick evaluation tool in terms of solar heat gains for architects in building early stage as it has an advantage over detailed building simulation programs in terms of instant calculation and the limited need for predefined input data
Even though solar energy is used as a passive solution that can compensate the heating demand of a building, the thermal performance of a building should be analyzed on an annual basis, as excessive solar heat gains in the summer period can result in overheating and an increase of cooling demand [1]

Summary

Introduction

Solar energy is the largest untapped energy source, which used in a smart way can result in great active and passive energy savings in building sector. Even though solar energy is used as a passive solution that can compensate the heating demand of a building, the thermal performance of a building should be analyzed on an annual basis, as excessive solar heat gains in the summer period can result in overheating and an increase of cooling demand [1]. In terms of new buildings, passive solar solutions should be considered in the early design stages of the building, as with simple measures it is possible to reduce the high amount of CO2 emissions in building sector, as it is the largest source of emissions in European Union [2]. For making solar calculations accessible for a regular user, there is a need to develop simplified energy calculators that require reduced order models

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