State of the Art on Retrofit Strategies Selection Using Multi-objective Optimization and Genetic Algorithms - Nearly Zero Energy Building Refurbishment - page 278

Fig. 2 The main objectives
for building retrofit
(Kolokotsa et al. 2009 )

Main
Objectives

Global
Environment

Indoor
Environment

Energy Use Cost

Regarding costs, the following objectives have been used:

• direct costs and initial investment costs (Rosenfeld and Shohet 1999 );
• cost of retrofit (Asadi et al. 2012a );
• economic life span (Rosenfeld and Shohet 1999 );
• annual ongoing maintenance charges (Rosenfeld and Shohet 1999 ; Rey 2004 );
• annual ongoing charges (Rey 2004 );
• net present value (NPV) of the energy investment (Martinaitis et al. 2007 );
• internal rate of return (IRR) of the energy investment (Martinaitis et al. 2004 );
• cost of conserved energy (CCE) (Martinaitis et al. 2004 ); and
• life cycle cost (LCC) (Wang et al. 2005 ).

As far as global environment is concerned, the objectives usually set are as
follows:
• annual emissions global warming potential (GWP) in kgeqCO 2 /m 2 (Rey 2004 );
• reduction potential of global warming emissions (Alanne 2004 );
• life cycle environmental impact (Wang et al. 2005 );
• acidification potential in kgeqSO 2 /m 2

(Rey 2004 ; Alanne et al. 2007 ); and

• water use (Alanne et al. 2007 ).

Indoor environmental quality and comfort have subcategories for the evaluation
of thermal sensation, visual comfort, indoor air quality, and acoustic comfort
(Kolokotsa et al. 2009 ). More specifically, regarding thermal comfort, the fol-
lowing objectives and indicators have been used:

• PMV-PPD thermal comfort indices based on ISO-7730 standard (ISO 2005 );
• dry resultant temperature for unconditioned buildings (Bouchlaghem 2000 );
• indoor temperature and humidity (Jaggs and Palmer 2000 );
• discomfort hours during summer or winter (Roulet et al. 2002 );
• daily overheating in K (Rey 2004 );
• effective draught temperature index (Rutman et al. 2005 );
• summer thermal discomfort severity index, which indicates the severity of
excessive mean radiant temperature during summer (Becker et al. 2007 ); and
• total percentage of cumulative time with discomfort (Asadi et al. 2012b ).

For visual comfort, the assessment objectives can be as follows:

• daylight availability (Radford and Gero 1980b );
• lighting and visual comfort [e.g., EPIQR method, see (Bluyssen and Cox 2002 ;
Rey 2004 )];