Energy Saving Generated Through Automatic Lighting Control Systems According to the Estimation Method of the Standard EN 15193-1

The standard EN 15193-1:2017 "Energy performance of buildings - Energy requirements for lighting" introduced a detailed method to calculate the energy demand for lighting in buildings. The method contains a calculation of the daylight supply, which accounts for the impact of lighting control systems, both daylight-linked and occupancy-based. This paper presents the results of a study carried out to quantify, with respect to a manual on/off switch, the energy savings due to the four typologies of daylight-linked controls included in the standards, as well as their combination with an occupancy auto off control. To highlight the factors that affect the amount of saved electric energy, several spaces were considered, with different daylight availability, windows orientation and shading system, located in sites at different latitudes and climate conditions, and considering two types of building: offices and classrooms. A database of 2880 cases was built. As a second step of the study, for each site and type of control, the minimum window-to-wall ratio necessary to obtain a pre-defined saving was calculated. The results show for what combinations of variables two target savings of 20% and of 30% can be reached using the photodimming and occupancy controls contained in the standard

Light versus Energy Performance of Office Rooms with Curtain Walls: A Parametric Study

A parametric study aimed at identifying the best performing solution in terms of lighting, heating and cooling demand minimization for an office room is presented. Different orientations, room and façade lay-outs, glazing and lighting control systems have been combined and 192 configurations have been analysed through a two-step process: daylight factor and dynamic daylighting metrics and the corresponding energy demand for lighting were calculated in step 1 using Daysim; the energy demand for heating and cooling was determined in step 2 using a quasi-steady state approach, to verify whether the best configurations obtained in step 1 also resulted in the lowest global energy demand

A novel methodology to spatially evaluate DGP classes by means of vertical illuminances. Preliminary results

A novel methodology to overcome the main limit of the Daylight Glare Probability DGP (i.e. the heavy computational time for an annual analysis of the DGP profile in one point) is presented. This uses a proxy based on the vertical illuminance (Ev) at the eye level. To do so, the most suitable value of Ev, to substitute DGP, is found by means of a comparison to the corresponding DGP value through a fault-detection diagnosis technique. The methodology was applied to a representative enclosed office with one South-facing window (Window-to-Wall Ratio of 50%) located in Turin. The glazing was assumed to have different transmission properties (specular and scattering) with different visible transmittances (in the range 3%-66%). The error in the estimation of the DGP classes calculated through the eye vertical illuminance was evaluated, for an analysis period of a whole year. The main advantages of the methodology proposed lie (i) in a significant reduction of the computational time required for its application and (ii) in the possibility of evaluating glare conditions not only for one or few points, but for a grid of points across a considered space. Its main limitation lies on its inability to quantify the exact DGP value, returning instead, at every time-step, the DGP class of performance

Phase Change Materials in Glazing: Implications on Light Distribution and Visual Comfort. Preliminary Results

The visual comfort concerned with a technology with PCM embedded into a double glazing unit was analyzed, using the Daylight Probability Glare and the ‘Useful Illuminance’ (percent of workplane with an illuminance in the range 100-3000 lx). A sample office room was modeled using Radiance, under a clear sky and with the façade facing south. The visible transmittance of PCM was measured in laboratory and used as input in Radiance. The simulations were carried out for the two solstices and the Autumn equinox (four hours per day), for three sites (Östersund, 63.2°N; Turin, 45.2°N; Abu Dhabi, 24.4°N), considering the solid state of the PCM only

A Methodology to Link the Internal Heat Gains from Lighting to the Global Consumption for the Energy Certification of Buildings in Italy

This paper critically discusses the procedure prescribed by the Italian Technical Standards to account for the internal gains in the calculation of the energy performance indices for a building. This procedure is based on a tabular value set depending on the building usage only (e.g., 6 W/m2 for office buildings), independently of the site and of the controls for blinds and lighting systems. Instead, the paper proposes a new procedure, which relies on the lighting energy numerical indicator (LENI) according to the European Standard EN 15193:2007. Basically, the procedure consists of the following steps: 1) internal gains from lighting are calculated accounting for the integration between electric appliances and daylighting; 2) these gains are summed to the internal gains from occupants and appliances; 3) the global gains are used as input data to calculate the energy performance indices for an office building (for space heating, space cooling, and lighting consumption) following the Italian Technical Standards. The office building which was used as case-study is the Department of Energy of the Politecnico di Torino. This was assumed to be located both in Turin (northern Italy) and in Palermo (southern Italy). In the study, the use of a manual on/off switch and of a photodimming sensor was also compared. For each configuration, the single and the global energy performance indices were calculated comparing two approaches to calculate the internal gains (Italian standard vs. new proposed procedure): a shift of one energy class for the building energy label was observed depending on the approach, which was used

A novel translucent concrete panel with waste glass inclusions for architectural applications

This paper explored the potential reuse of coarse glass wastes as insert in a high performance cement matrix to produce translucent concrete panels that can be aggregated into partition walls, through a supporting frame. The effects of glass scraps on mechanical and optical-photometric properties of panels were tested. Two different series of panel prototypes were manufactured, with and without steel-reinforcing fibers. Compressive and flexural tests were performed on cement matrices and translucent panels. The annual impact on the amount of daylight in a room with two translucent concrete opposite interior walls and the room energy demand for lighting were estimated using a daylight simulation software for a number of rooms with varying window-to-wall ratio, orientation, site, illuminance over the work plane, lighting power density, type of partition walls (with different percentages of glass cullet inclusions)