Paper Conference

Proceedings of eSim 2018: 10th Conference of IBPSA-Canada


Snow/ground reflectivity model for simulating energy use in buildings

Luminita Dumitrascu, Ian Beausoleil-Morrison

Abstract: The paper describes the development of an empirical model for predicting ground and snow reflectivity. Ground reflected solar radiation is among the factors having a significant impact on heating/cooling load calculation, solar collector performance, and building energy use prediction. The presence of snow can increase the reflectivity of the ground, leading to increased solar radiation incident on various surfaces of a building. It is common for building performance simulation users to employ the default values of ground reflectivity which can lead to significant inaccuracies, especially for the period when ground is covered by snow. A new model is derived based on point measurements of incoming (global horizontal) and reflected solar radiation taken for a fifteen-month period (December 2016 – March 2018), at Carleton University, Ottawa. An algorithm is developed for three periodsground free of snow, non-melting or snow accumulation, and melting. The main predictors of reflectivity were found to be the followingzenith angle, cloud cover, and snow age.
Keywords: building performance simulation, ground/snow reflectivity, zenith angle, cloud cover, snow age
Pages: 443 - 452