Uncertainty of Energy and Economic Performance of Manual Solar Shades in Hot Summer and Cold Winter Regions of China

Abstract

Occupant behavior is recognized as a major source of discrepancy between simulated and actual energy consumption. This study investigates the uncertainty of energy and economic performance of manual solar shades for the south facade. A developed stochastic model for manual solar shades based on a discrete-time Markov chain method was constructed in Building Controls Virtual Test Bed (BCVTB) for co-simulation with EnergyPlus. The stochastic shade model was compared with deterministic models concerning energy savings potential and life cycle economic performance at different building scales (i.e., from a single room to a whole building). The results show that annual energy uncertainty, due to occupant behavior, on manual shades can be neglected at the building level, whereas for sizing heating equipment, energy uncertainty should be considered. The payback period for manual shades is about 10 years and, in general, a larger building has a higher economic performance. Comparative analysis shows that there is a relatively big performance overestimation or underestimation by commonly used deterministic models in building simulation tools, and thus may lead to a biased economic analysis or even an inappropriate design decision when comparing different energy-saving measures.

Minimum number of simulation runs for reliable building energy and peak load prediction at different building scales: a study on stochastic shade adjustment

“…Thus, repeated simulation runs are needed to obtain the possible distribution of the simulation output (cooling, heating and total energy demands). To have a balance between computational cost and high accuracy, a suitable number of simulation runs was determined according to the graphical method recommended in (Robinson 2014), which has been used for similar analysis in previous papers (Yao and Zheng 2019;Chapman, Siebers, and Robinson 2018). The minimum number of repeated simulations required is defined by the point at which the line (the cumulative mean of the simulated annual energy demand) becomes flat.…”

“…This model has the benefits of considering partial shading states and was validated with realistic shade behavior patterns in that building. Energy, thermal, visual and life cycle economic performance of manual shades have been studied (Yao 2014;Yao 2018a;Yao, Chow, and Chi 2016;Yao 2019;Yao and Zheng 2019). This paper is a continuation of previous research and the focus of the current research is: (1) to compare shading performance difference between east, south and west facades; (2) to compare the difference in energy performance and uncertainty levels among the three facades; and (3) to determine the minimum number of simulation runs to obtain reliable annual energy and peak heating/cooling loads at different building scales.…”