Sensitivity analysis for robust design of building energy systems

The comprehensive design of building systems incorporates the tasks of selection, sizing and control of devices. A simultaneous acquirement of these tasks is a necessity to achieve an overall optimal design. However, such mutual optimizations become a complex problem, implying a high computational effort. A greater challenge appears once the uncertainties of boundary conditions such as weather conditions, user demands and energy costs are taken into account. A common approach to protect the suggested system configuration against the possible uncertainties is a stochastic optimization which results in a robust design. In this paper, first the sensitivity of the design to selected boundary conditions is extensively investigated. In a second step, the resulting designs of the deterministic and stochastic optimizations are compared for several uncertainties. All optimizations are setup using a previously developed framework which is extended to solve the stochastic optimization problem. The comprehensive analyses show that the achievement of a robust design is computationally demanding and not even desirable in general. However, the size of devices may vary by up to 100% when a robust design is attained. •Describing a tool for simultaneous design and control of building energy systems.•Mixed-integer linear programming of thermal and electrical devices in buildings.•Formulation of deterministic and stochastic optimization problems.•Sensitivity analysis for investigating the effects of uncertainties on the design.•A measure to assess the necessity of a robust design in a case study.