Building Performance Optimization of Net Zero-Energy Buildings - Modeling, Design, and Optimization of Net-Zero Energy Buildings - page 263

- Transparent exploration is presented via multistage optimization
showing the effect of the design-variable combinations on the objective
and constraint functions,
- Time-saving exploration is achieved by speeding up the exploration
by avoiding the unrealistic/unfeasible design-variable combinations
and using presimulated results instead of running time-consuming
simulations (when possible).
5.3.2 Case Study: Single-Family House in Finland
In order to find optimal trade-off relations between PEC and dLCC for
a single-family house in the cold climate of Finland, a multi-stage
optimization method is proposed to explore more than 3 × 10 9 (16 × 8 ×
13 × 3 × 3 × 4 × 3 × 2 × 4 × 31 × 71) combinations of the design-variable
options( Table5.1 ) .ThedLCCiscalculatedfor30years.Thedesignvariables
are selected to cover packages of measures ranging from compliance with
the requirements of the current Finnish building code (C3-2010) to
combinations that realize Nearly ZEBs (e.g., U -values typical of a
Passivhaus, photovoltaic, and solar thermal collectors). The variables
include a number of external wall, roof, and floor insulation thicknesses,
three building tightness levels, three window types, four shading methods,
three heat recovery units, two cooling options, four heating systems, and
different sizes of on-site solar systems. The detailed description of the
design variable option can be found in Hamdy, Hasan, and Siren (2013).
A reference case is calculated according to the National Building Code of
Finland C3-2010. The life cycle costs of the candidate solutions are
calculated relative to the reference case one. Considering the impact of the
design variables on the objective functions (PEC and dLCC), the exploration
is performed in three stages:
• Stage -1 aims to find the optimal combinations of the design variables
that influence the building thermal performance (heating, cooling, and
thermal comfort) of the house, that is, building envelope parameters
and a heat recovery ventilation system;
• Stage -2 assesses the economic and environmental viability of the
studied primary heating/cooling systems to the optimal building
combinations (packages) found in Stage -1; and,