Distributed evolutionary algorithm for co-optimization of building and district systems for early community energy masterplanning

Buildings play a significant role in climate change mitigation. In North America, energy used to construct and operate buildings accounts for some 40% of total energy use, largely originating from fossil fuels. The strategic reduction of these energy demands requires knowledge of potential upgrades prior to a building's construction. Furthermore, renewable energy generation integrated into buildings façades and district systems can improve the resiliency of community infrastructure. However, loads that are non-coincidental with on-site generation can cause load balancing issues. This imbalance is typically due to solar resources peaking at noon, whereas building loads typically peak in the morning and late afternoon or evenings. Ideally, the combination of on-site generation and localized storage could remedy such load balancing issues while reducing the need for fossil fuels. In response to these issues, this paper contributes a methodology that co-optimizes building designs and district technologies as an integrated community energy system. A distributed evolutionary algorithm is proposed that can navigate over 10154 potential community permutations. This is the first time in literature that a methodology demonstrates the co-optimization of buildings and district energy systems to reduce energy use in buildings and balance loads at this scale. The proposed solution is reproducible and scalable for future community masterplanning studies

Daylight Performance of Perimeter Office Façades utilizing Semi-transparent Photovoltaic Windows: A Simulation Study

AbstractThis paper presents the potential impact of semi-transparent photovoltaic windows on the daylighting performance of commercial building façades. The performance of three façade configurations is examined, integrating Si-based, opaque spaced cells and transparent thin film technologies. Simulation results suggest that a semi-transparent photovoltaic module with visible effective transmittance of 30%, integrated as the outer glass layer of a double-glazed window, provides sufficient daylight within the perimeter zone throughout the year, with sDA300lx/50%=1 and DGI=5%. Moreover, a three-section façade configuration integrating Si-based spaced PV cells on the upper section and thin film PV on the middle section of the façade has the potential to maximize daylight utilization and the view to the outdoors

Energy performance, comfort, and lessons learned from an institutional building designed for net zero energy

This paper examines the early performance ofthe Varennes Library, a building designed for net-zero annual energy balance in Varennes, near Montreal, Canada. It produces electricity from a 110.5 kWp building-integrated photovoltaic (BIPV) system where heat is also recovered from a section of the array and used to preheat the outdoor air intake. The building's many architectural and mechanicalfeatures were integrally designed to achieve the net zero energy target over a five-year averaging period with several key decisions made at the early design stage. These include the shape, area, and orientation ofthe roofthat maximizes electricity productionfrom the BIPV (part BIPV/T [building-integrated photovoltaic/thermal with heat recovery]) system and a design layout that promotes daylight penetration and natural ventilation/free coolingduring the cooling season. In thefirstyear after inauguration, an operational energy use intensity (EUI) of 24.8 kBtu/tfy (78.1 kWh/m2y) was achieved and has since been reduced to 22.20 kBtu/fy (70.0 kWh/m2y). Considering renew-ables production, the net-energy use intensity (EUI) is 4.60 kB tu/ fi2y (14.5 kWh/m2y). This is a 95% EUI reduction over the national institutional average and can be further reduced with additional (ongoing) commissioning efforts. Suggested improvements in operation include ensuring the electricity production is optimized and any faults corrected, dimming electric lighting when daylight is sufficient, extending the hours of natural ventilation, and better utilization of the hydronic radiant slab for thermal storage using predictive controls. This paper discusses the process followed in the design of the library, its key features, its early performance, and some of the lessons learned

Buildings integrated phase change materials: modellings and validation of a novel tool for the energy performance analysis

In this paper a novel dynamic energy performance simulation model for the Phase Change Materials (PCM) analysis is presented. The model is implemented in a suitable computer code, written in MatLab and called DETECt, for complete building energy analyses. In the presented model, the “effective specific heat” method is implemented. Here, the specific heat of each PCM layer changes as a function of the system phase and temperature in both melting and freezing processes. A model validation is carried out by comparing numerical results vs. measurements obtained at Solar Laboratory of Concordia University (Montreal, Canada). The simulation model allows exploring the potential of PCMs to increase the thermal inertia of buildings envelopes and to assess the effects/weight of several design parameters (e.g. PCMs melting temperature, etc.) on the building heating and cooling energy demand and on the related thermal comfort. In order to show the potentiality of the presented simulation model, suitable case studies referred to residential and office buildings, to three different weather conditions and to two alternative PCM layouts in the building envelope, are developed