Evaluation of electrochromic windows impact in the energy performance of buildings in Mediterranean climates

Abstract

Energy performance analysis of Electrochromic (EC) windows is carried out. EC glass and control strategies are modeled and implemented in ESP-r. EC windows are evaluated, on a test prototype, as an alternative to shading devices. Set-points and measured variables are used to control optical properties of EC glass. Within this context, the paper focuses on the energy savings that may occur when using electrochromic (EC) windows, an interesting emerging technology alternative to shading devices to control solar gain in buildings located in Mediterranean climates. The EC windows technology is briefly presented and the optical properties adjustments of the glasses are discussed according to the operated range. The EC window dynamic behavior and the different control strategies are modeled and implemented in the ESP-r building simulation program. The EC window impact in the energy needs for heating and cooling is studied, considering different ambient parameters (exterior dry bulb temperature, interior dry bulb temperature and incident radiation) and set points for the EC control. A comparison of several windows solutions (single, double-glazing and EC windows), the type of building, internal gains from occupancy, lighting and equipment and the orientation of windows are considered for discussion through the analysis of the energy needs for heating and cooling. It is concluded that for this climate the best positive results are obtained when the EC are used in the west façade. For the south façade the results show no significant advantages in using EC windows.

The energy performance of windows in Mediterranean regions

“…In order to reduce solar heat gain and still retain a satisfactory level of daylighting energy-efficient designs on window configurations are needed [17]. Appropriate solar protection or glazings with controllable properties can assist significantly toward the enhancement of building energy performance especially during the cooling season and for eastern or western facades in particular [18].…”

United States energy and CO2 savings potential from deployment of near-infrared electrochromic window glazings

“…Earlier studies of electrochromic glazings have found that the technology could save 10%e20% primary energy consumption in perimeter building zones in commercial buildings across much of the U.S. relative to stocktypical windows [3]. A recent simulation study found cooling energy savings as high as 37 kWh/m 2 of glass for east and west facing facades in a Mediterranean climate compared with single and double pane windows [4]. Another simulation study found dynamic glazings applied to a split-pane window produced lighting savings of 37%e48% compared with a static window with occupant controlled blinds [5].…”

Multicolor electrochromic thin films and devices based on the Prussian blue family nanoparticles

“…The spectral modulation capabilities and reversible redox properties of EC materials have led to the applications of visualized-transducers [3], windows [4,5], switchable mirrors [6], displays [7,8], and energy-saving buildings [9,10]. As far as solar-attenuation smart windows are concerned, a variety of inorganic [11,12] and organic [13,14] materials have been investigated and processed as thin films for device assembly to date.…”