Monitoring protocol to assess the overall performance of lighting and daylighting retrofit projects

In the field of lighting and daylighting, standard monitoring procedures to assess the overall performance of retrofit projects are scarce. Nevertheless the access to monitored data is crucial to assess whether daylighting or electric lighting systems deliver the expected performance in terms of cost-effectiveness and energy efficiency. In order to bridge this gap, a monitoring protocol is under development as part of the International Energy Agency – Solar Heating and Cooling Programme (IEA-SHC) Task 50 ‘Advanced Lighting Solutions for Retrofitting Buildings’. The protocol focuses on lighting and/or daylighting (façade or roof) retrofit in the non-residential building stock. It covers four key aspects: energy efficiency, costs, quality of the lighting environment and user satisfaction. The main features of this protocol are presented in this paper, along with some lessons learned from the ongoing application on selected case studies

Performance Evaluation of Lighting and Daylighting Retrofits: Results from IEA SHC Task 50

AbstractThis article presents some results from a large monitoring campaign performed in 22 buildings around the world as part of International Energy Agency (IEA) Task 50 “Advanced lighting solutions for retrofitting buildings”. This article mainly addresses the work of Subtask D, which aims to demonstrate sound lighting retrofit solutions in a selection of representative, typical Case Studies. In order to evaluate the Case Studies, a monitoring protocol was developed to assess the overall lighting performance taking into consideration: 1) Energy use, 2) Retrofit costs, 3) Photometric assessment, and 4) User assessment. The monitoring was carried out from June 2014 to December 2015 in 22 non-residential buildings in ten countries. This article presents results from selected Case Studies, drawing conclusions regarding retrofit solutions as well as reflecting on methodological procedures for the measurements and data collection. Measured data as well as key conclusions from Subtask D will be summarized in an electronic web and portable sourcebook at the end of the IEA Task 50 (December 2015), which will be freely available through the Internet

Survey on opportunities and barriers in lighting controls

This report summarizes a survey performed in eight countries on the status quo of daylight and electric lighting control systems. Feedback from more than 100 international experts (building / facility managers and planers) was evaluated. The aim of the survey was to identify the perception of the different possibilities of the current lighting control solutions and the expectations about the control systems. The survey aims to provide a mapping of the current lighting control systems available at the market and an overview of which functions are perceived as most important and which areas are found to be improved. Participants of the survey had to rank each question in relation to the perceived importance and the need for improvement. The survey enclosed five general topics; energy, operational aspects, occupant control, occupant comfort and control functionality.The findings from the summary suggest, that the two main reasons for the implementation of lighting control systems are:1. The possibility to reduce the electric lighting consumptions and2. The opportunity to increase the user’s well-being and thereby reduce complaints from the users.From a user perspective, this means that the lighting system must ensure visual acuity and comfort by providing a sufficient level of illuminance and the ability to regulate the light level. Always in relation to the task and the ambient light in the space, and thereby creating a pleasant and comfortable light environment. Research suggests, when giving the users some manual control possibilities, the satisfaction with the lighting conditions in general increases The users should be able to both increase and dim the light levels or completely turn it off. Thissuggests, if the lighting control system is designed to regulate the illuminance automatically, it should be provided some kind of manual override. This is supported by the findings in the surveys, where all countries in one way oranother find it important to provide the users with some possibility of user control. This as well applies to the control of the shading system in relation to avoid glare from high daylight intensities and undesired solar radiationcoming into the space. This increases the risk of overheating, resulting in an increased ventilation and/or cooling need leading to a higher energy use. However, in the two Scandinavian countries, it is found less important withthe possibility to control the shadings in order to reduce glare from daylight and undesired heat transmission in the space. This may be due to the higher latitude and thereby a lower intensity of the daylight.In relation to the importance of user control, the findings additionally suggest, that the occupant control must be simple to operate. A control system which is easy for the users to understand intuitive, will most likely increase the chances of an ‘optimal’ interaction with the system. If the system does not meet the users need or is too complex to use, the possibility that the users will try to override the control systems increases, and this will most likely result in increased energy consumption

Integrating daylighting and lighting in practice: Lessons learned from international case studies

This report presents lessons learned from twenty-five worldwide real-life case studies implementing the integration of daylighting and electric lighting. The case studies were monitored with respect to energy use for lighting, visual performance, non-visual performance, and users’ satisfaction. The monitoring is largely based on field measurements, but it is also complemented with simulations and calculations where needed. The report is divided in two parts. The first part provides an overview of the case studies and the overall lessons learned. The second part provides factsheets for each of the case studies; the factsheets include details on the monitoring, results, and specific lessons learned. Based on the lessons learned from the case studies, this report concludes that: • The energy demand for lighting is drastically reduced thanks to the combined effect of more efficient light sources, advances in controls, and raised awareness in the integration of daylighting and electric lighting. • Integrative lighting is currently driving the innovation in lighting technology and wider implementation is expected as knowledge in the field of non-visual requirements for lighting expands. • However, the current integration of the integrative lighting concept with daylighting in practice is limited, which may result in significant energy rebound (increases). • Daylighting integration is of utmost importance for achieving quality beyond energy savings. • Integrated daylighting and electric lighting design is facing new challenges: questions connected with comfort and health are yet to be answered

Modeling the direct sun component in buildings using matrix algebraic approaches: Methods and validation

Simulation tools that enable annual energy performance analysis of optically-complex fenestration systems have been widely adopted by the building industry for use in building design, code development, and the development of rating and certification programs for commercially-available shading and daylighting products. The tools rely on a three-phase matrix operation to compute solar heat gains, using as input low-resolution bidirectional scattering distribution function (BSDF) data (10–15° angular resolution; BSDF data define the angle-dependent behavior of light-scattering materials and systems). Measurement standards and product libraries for BSDF data are undergoing development to support solar heat gain calculations. Simulation of other metrics such as discomfort glare, annual solar exposure, and potentially thermal discomfort, however, require algorithms and BSDF input data that more accurately model the spatial distribution of transmitted and reflected irradiance or illuminance from the sun (0.5° resolution). This study describes such algorithms and input data, then validates the tools (i.e., an interpolation tool for measured BSDF data and the five-phase method) through comparisons with ray-tracing simulations and field monitored data from a full-scale testbed. Simulations of daylight-redirecting films, a micro-louvered screen, and venetian blinds using variable resolution, tensor tree BSDF input data derived from interpolated scanning goniophotometer measurements were shown to agree with field monitored data to within 20% for greater than 75% of the measurement period for illuminance-based performance parameters. The three-phase method delivered significantly less accurate results. We discuss the ramifications of these findings on industry and provide recommendations to increase end user awareness of the current limitations of existing software tools and BSDF product libraries

Validation of the Five-Phase Method for Simulating Complex Fenestration Systems with Radiance against Field Measurements

The Five-Phase Method (5-pm) for simulating complex fenestration systems with Radiance is validated against field measurements. The capability of the method to predict workplane illuminances, vertical sensor illuminances, and glare indices derived from captured and rendered high dynamic range (HDR) images is investigated. To be able to accurately represent the direct sun part of the daylight not only in sensor point simulations, but also in renderings of interior scenes, the 5-pm calculation procedure was extended. The validation shows that the 5-pm is superior to the Three-Phase Method for predicting horizontal and vertical illuminance sensor values as well as glare indices derived from rendered images. Even with input data from global and diffuse horizontal irradiance measurements only, daylight glare probability (DGP) values can be predicted within 10% error of measured values for most situations

DALEC - výpočet energetické náročnosti osvětlovacích soustav s denním a umělým osvětlením a jejich vliv na energetické požadavky vytápěcích a chladících soustav s uvažováním řídících strategií pro různé

DALEC is a new free web tool (www.dalec.net). Based on climate files DALEC allows energy calculation for artificial and daylight systems and their impact on heat and cooling loads in real-time. In this paper case studies are presented which demonstrate the impact of different control strategies for artificial and daylight systems in varying geographic climate zones on energy demand for lighting, heating and cooling