Daylighting Performance of Solar Control Films for Hospital Buildings in a Mediterranean Climate

One of the main retrofitting strategies in warm climates is the reduction of the effects of solar radiation. Cooling loads, and in turn, cooling consumption, can be reduced through the implementation of reflective materials such as solar control films. However, these devices may also negatively affect daylight illuminance conditions and the electric consumption of artificial lighting systems. In a hospital building, it is crucial to meet daylighting requirements as well as indoor illuminance levels and visibility from the inside, as these have a significant impact on health outcomes. The aim of this paper is to evaluate the influence on natural illuminance conditions of a solar control film installed on the windows of a public hospital building in a Mediterranean climate. To this end, a hospital room, with and without solar film, was monitored for a whole year. A descriptive statistical analysis was conducted on the use of artificial lighting, illuminance levels and rolling shutter aperture levels, as well as an analysis of natural illuminance and electric consumption of the artificial lighting system. The addition of a solar control film to the external surface of the window, in combination with the user-controlled rolling shutter aperture levels, has reduced the electric consumption of the artificial lighting system by 12.2%. Likewise, the solar control film has increased the percentage of annual hours with natural illuminance levels by 100–300 lux

Review of simulating four classes of window materials for daylighting with non-standard BSDF using the simulation program Radiance

This review describes the currently available simulation models for window material to calculate daylighting with the program "Radiance". The review is based on four abstract and general classes of window materials, depending on their scattering and redirecting properties (bidirectional scatter distribution function, BSDF). It lists potential and limits of the older models and includes the most recent additions to the software. All models are demonstrated using an exemplary indoor scene and two typical sky conditions. It is intended as clarification for applying window material models in project work or teaching. The underlying algorithmic problems apply to all lighting simulation programs, so the scenarios of materials and skies are applicable to other lighting programs

Theoretical and experimental investigation of Polymer Dispersed Liquid Crystal glazing for Net-Zero energy buildings in Saudi Arabia and UK

In the last few years, energy consumption in the building sector has increased significantly because of the economic and population growth in Saudi Arabia and the United Kingdom. Governmental bodies and policymakers have invested greatly to implement measures to reduce the energy demand and carbon emissions for the building sector. Recently, a new technology of smart windows has emerged such as Polymer Dispersed Liquid Crystal Smart Glazing (PDLC). It has the potential to dynamically control the transmittance of solar radiation into a building by altering the optical and thermal properties. To evaluate the PDLC glazing for building applications, certain properties such as spectral transmission, thermal, and daylight performance need to be investigated. Therefore, this research aims to investigate PDLC glazing to characterise the thermal and daylight performance for energy efficiency for buildings in Saudi Arabia and the United Kingdom. To investigate the thermal and daylight performance of PDLC glazing, theoretical and experimental methodologies were used. In the indoor experiment, the PDLC glazing was investigated to evaluate the spectral transmission and determine the thermal properties. In the outdoor experiment, the PDLC glazing was investigated with and without a solar control film to evaluate the thermal behaviour and daylight performance under various sky conditions. Furthermore, the EnergyPlus simulation tool was used to perform building energy modelling and daylight analysis to evaluate the potential of energy saving of the PDLC glazing for an office building in Saudi Arabia (arid climate) and the United Kingdom (temperate climate). The result of the indoor investigation showed that the investigated PDLC glazing has 2.79 W/m2·K and 2.44 W/m2·K for transparent and opaques states, respectively. In addition, the outdoor evaluation revealed that the PDLC glazing effectively reduced solar heat gain when switched to the opaque state. Visual comfort was also achieved in all sky conditions (sunny, intermittent, cloudy) when a solar control film was attached to the PDLC glazing. In terms of energy savings, the EnergyPlus analysis showed that the PDLC glazing reduced cooling load by 12.7% in Riyadh and heating load by 4.9% in London

Daylighting and Thermo-Electrical performance of an Autonomous Suspended Particle Device Evacuated Glazing

Suspended particle device (SPD) glazing is an AC powered switchable glazing. PV powered SPD evacuated (vacuum) glazing was proposed with the potential of reducing the heating demand, cooling demand and artificial lighting demand of a building. To achieve an autonomous SPD vacuum glazing, semi empirical simulation and outdoor characterisation was explored in this thesis. Transmission of SPD glazing (area 0.058 m2) varied from 5% when opaque to 55% when transparent in the presence of 110 V, 0.07 W AC supply was characterised in outdoor test cell in Dublin. The SPD glazing has variable spectral transmission in the presence of variable applied voltage, with high transmission in the near infrared between 700 to 1100 nm. 30% transparent SPD glazing in a particular room configuration provided a constant 4% daylight factor with acceptable glare. Use of a 0.34 m2 vertical photovoltaic (PV) panel was investigated to self-power (autonomous) an SPD glazing system. The dynamic behaviour of the PV-powered SPD glazing gave good switching times that would maintain occupant comfort. It was observed that SPD material inside a glazing unit absorbs solar radiation giving a high glazing surface temperature. For this SPD glazing alone, the overall heat transfer coefficient (U-value) was found to be 5.9 W/m2K typical of a single glazing. A SPD switchable double-glazing, was found to have a U-value of 1.99 W/m2K. A vacuum glazing was attached to the SPD glazing was found to have a U-value of 1.14 W/m2K

Wireless sensors and IoT platform for intelligent HVAC control

Energy consumption of buildings (residential and non-residential) represents approximately 40% of total world electricity consumption, with half of this energy consumed by HVAC systems. Model-Based Predictive Control (MBPC) is perhaps the technique most often proposed for HVAC control, since it offers an enormous potential for energy savings. Despite the large number of papers on this topic during the last few years, there are only a few reported applications of the use of MBPC for existing buildings, under normal occupancy conditions and, to the best of our knowledge, no commercial solution yet. A marketable solution has been recently presented by the authors, coined the IMBPC HVAC system. This paper describes the design, prototyping and validation of two components of this integrated system, the Self-Powered Wireless Sensors and the IOT platform developed. Results for the use of IMBPC in a real building under normal occupation demonstrate savings in the electricity bill while maintaining thermal comfort during the whole occupation schedule.QREN SIDT [38798]; Portuguese Foundation for Science & Technology, through IDMEC, under LAETA [ID/EMS/50022/2013

Adaptive facade network — Europe

Energy efficient buildings significantly contribute to meeting the EU climate and energy sustainability targets for 2020 as approximately one-third of all end-user energy in Europe today is consumed by space heating/cooling, ventilation and lighting of buildings. In this context, the energy performance of future building envelopes will play a key role.  The main aim of COST Action TU1403 with 120 participants from 26 European countries is to harmonise, share and disseminate technological knowledge on adaptive facades on a European level and to generate ideas for new innovative technologies and solutions