Civil Engineering Reference
In-Depth Information
Energy Performance Indoor Environmental Quality Retrofit Methods for
Apartment Building Refurbishment (EPIQR) (Jaggs and Palmer
2000
) and Tool
for Selecting Office Building Upgrading Solutions (TOBUS) (Caccavelli and
Gugerli
2002
) are other tools using MCDA techniques for building retrofit actions
selection. The TOBUS method aims at offering a tool for selecting office build-
ing's retrofit solutions with respect to multiple criteria. One of the key elements to
reach this goal was an assessment of the degree of physical degradation, extent of
any degradation, extent of the necessary work to retrofit the building, and the costs.
Kaklauskas et al. (
2005
) used multivariate design and MCDA to prioritize and
rank the alternative solutions for the refurbishment of a building envelope. The
alternatives' significance, utility degree, and priority are extracted using this
methodology and, as a consequence, the strongest and weakest points of the
refurbishment are revealed.
Alanne (
2004
) combines MCDA and a knapsack (multi-objective) model to
support building retrofit. MCDA is used to extract the utilities of the retrofit
actions proposed, as well as the total utility versus the selected criteria. The utility
scores obtained are then used as weights in a knapsack optimization model to
identify the actions that should be undertaken, through the maximization of the
objective function (that is, utility score achieved by selecting the retrofit action,
specified by environmental value and functionality) subject to budget constraints.
Simulation-based Approaches
Simulation-based approaches are either simplified (analytical methods) or detailed
(numerical methods) using powerful simulation programs.
In the simulation-based process, a basic model of the building is developed
using simulation tools. Then, through an iterative procedure, a series of recom-
mendations are defined using the best construction practice (Horsley et al.
2003
).
These recommendations may include increase in insulation, change of glazing, etc.
There are a number of detailed building energy simulation packages, such as
EnergyPlus, eQuest, DOE-2, ESP-r, BLAST, HVAC-SIM+, TRNSYS, etc. A
detailed comparison of the capabilities of 20 building energy simulation packages
can be found in Ref (Crawley et al.
2008
).
For example, TRNSYS is used by Santamouris et al. (
2007
) to investigate the
energy-saving potential of green roofs in a nursery school in Greece. EnergyPlus is
used by Becker et al. (
2007
) to assess specific factors of building design elements
(window orientation, glazing type, thermal resistance of walls, etc.) and 20 venti-
lation strategies for schools' energy consumption and efficiency. Zmeureanu et al.
(
1999
) employed DOE-2 to estimate the energy savings due to building retrofits.
Although many sophisticated energy simulation programs are valuable to study
the impacts of different ECM on building performance, the iterative trial-and-error
process of searching for a better solution is time consuming and ineffective
because of the inherent difficulty in exploring a large design space.
The main problem when employing MCDA techniques is that they are applied
upon a set of predefined alternative courses of action. In case that a limited number
of such alternatives have been defined, there is no guarantee that the solution
