Combining Simulation and Optimisation for Dimensioning Optimal Building Envelopes and HVAC Systems

Aalto University, P.O. Box 11000, FI-00076 Aalto www.aalto. fi Author Mohamed Hamdy Hassan Mohamed Name of the doctoral dissertation Combining Simulation and Optimisation for Dimensioning Optimal Building Envelopes and HVAC Systems Publisher School of Engineering Unit Department of Energy Technology Series Aalto University publication series DOCTORAL DISSERTATIONS 177/2012 Field of research HVAC Technology Manuscript submitted 7 June 2012 Date of the defence 14 December 2012 Permission to publish granted (date) November 2012 Language English Monograph Article dissertation (summary + original articles) Abstract Responding to the international calls for high energy performance buildings like nearly-zero energy buildings (nZEB), recent years have seen significant growth in energy-saving and energy-supply measures in the building sector. A detailed look at the possible combinations of measures indicates that there could be a huge number (possibly millions) of candidate designs. In exploring this number of designs, looking for optimal ones is an arduous multi-objective design task. Buildings are required to be not only energy-efficient but also economically feasible and environmentally sound while adhering to an ever-increasing demand for better indoor comfort levels. The current thesis introduces suitable methods and techniques that attempt to carry out time-efficient multivariate explorations and transparent multi-objective analysis for optimizing such complex building design problems. The thesis’s experiences can be considered as seeds for developing a generic simulation-based optimisation design tool for high-energyperformance buildings. Case studies are made to illustrate the effectiveness of the introduced methods and techniques. In all the studies, IDA-ICE is used for simulation and MATLAB is implemented for optimisation as well as supplementary calculations. A new program (IDA-ESBO) is used to simulate renewable energy source systems (RESs). Using detailed simulation programs was important to investigate the impact of the energy-saving measures (ESMs) and the RESs as well as their effects on the thermal and/or energy performance of the studied buildings. The case studies yielded many optimal design concepts (e.g., the type of heating/cooling (H/C) system is a key element to achieve environmentally friendly buildings with minimum life cycle cost. The cost-optimal implementations of ESMs and RESs depend significantly on the installed H/C system). On building regulations, comments are taken. For instance, in line with the cost-optimal methodology framework of the European Energy Performance of Buildings Directive (EPBD-recast 2010), our study showed that the Finnish building regulation D3-2012 specifies minimum energy performance requirements for dwellings, lower than the estimated cost-optimal level by more than 15%. The adaptive thermal comfort criteria of the Finnish Society of Indoor Air Quality (FiSIAQ-2008) are strict and do not allow for energy-efficient solutions in standard office buildings. The thesis shows that it is technically possible to speed up the optimisation resolution of the building and HVAC design problems and to reach an optimal or close-to-optimal solution set. A simulation-based optimisation approach with a suitable problem setup and resolution algorithm can efficiently explore the possible combinations of design options and support informative, optimal results for decision-makers.