Smart cool mortar for passive cooling of historical and existing buildings: experimental analysis and dynamic simulation

In order to mitigate Urban Heat Island Effect and global warming, both governments and scientific community are working to reduce energy consumptions. In particular, the construction sector has a high potential in reducing energy demand, by means of both active and passive solutions. The European building stock is mainly composed by existing buildings as well as historical ones, which happens to be the less energy efficient ones. Moreover, retrofit operations are more complex on historical buildings, due to strict regulations for the preservation of such historical and cultural heritage. Considering this challenge, in this work we described and in lab analyzed possible passive solutions specifically designed for historical and existing buildings. In particular, we developed innovative cool colored mortars and tested them in lab, as well as investigated cool colored mortars, cool clay tiles and cool natural gravels performance when applied as envelope and roof elements, by means of dynamic simulation

The effect of cool paints and surface properties of the facade on the thermal and energy efficiency of buildings in a hot and arid climate

The facade of a building is a decisive factor in the thermal and energy performance of buildings. Its surfaces are considered as zones of heat transfer between the inside and the outside. Surface properties, especially color and texture; which have an important role on solar absorption and thermal emittance of the facade and subsequently the thermal operation of the building. The purpose of this article is to study the impact of surface properties of the facade on the thermal comfort and energy efficiency of buildings in a hot and arid climate. The investigation is based on an experimental approach by taking measurements in test cells with an insulating paint (with nanoparticles) as well as on a numerical study by the dynamic thermal simulation software TRNSYS. Several parameters were studied such as ambient temperature, internal and external surface temperature and energy consumption. The results showed that the surfaces of the facade represent with excellence the place of heat exchange between interior and exterior whose surface properties have a colossal impact on the thermal and energy operation of the building. The insulating paint with its nanoparticles has a considerable impact on the reduction of temperature. The proper choice of material absorption has a great influence on the reduction of temperatures and energy requirements of the building

The effect of cool paints and surface properties of the facade on the thermal and energy efficiency of buildings in a hot and arid climate

The facade of a building is a decisive factor in the thermal and energy performance of buildings. Its surfaces are considered as zones of heat transfer between the inside and the outside. Surface properties, especially color and texture; which have an important role on solar absorption and thermal emittance of the facade and subsequently the thermal operation of the building. The purpose of this article is to study the impact of surface properties of the facade on the thermal comfort and energy efficiency of buildings in a hot and arid climate. The investigation is based on an experimental approach by taking measurements in test cells with an insulating paint (with nanoparticles) as well as on a numerical study by the dynamic thermal simulation software TRNSYS. Several parameters were studied such as ambient temperature, internal and external surface temperature and energy consumption. The results showed that the surfaces of the facade represent with excellence the place of heat exchange between interior and exterior whose surface properties have a colossal impact on the thermal and energy operation of the building. The insulating paint with its nanoparticles has a considerable impact on the reduction of temperature. The proper choice of material absorption has a great influence on the reduction of temperatures and energy requirements of the building

Impact of Incorporating NIR Reflective Pigments in Finishing Coatings of ETICS

Near-infrared (NIR) reflective materials are being developed for mitigating building cooling needs. Their use contributes to broadening the range of colours, responding to the urban aesthetic demand without compromising the building performance. Despite the increase in NIR reflective pigments investigation, there is still a knowledge gap in their applicability, impact, and durability in multilayer finishing coatings of External Thermal Insulation Composite Systems (ETICS). Hence, the main goal of this work consists of evaluating the impact of incorporating NIR reflective pigments (NRP) in the solar reflectance of the surface layer of ETICS, without affecting the colour perception, as well as their influence on the colour durability and surface temperature. As such, colour, solar reflectance, and surface temperature were monitored for 2 years in dark-coloured specimens of ETICS, with and without NRP and a primer layer. It was confirmed that the main contribution of NRP is the increase of solar reflectance and, consequently, the decrease in surface temperature, especially for high exterior temperatures (around 30 degrees C). Moreover, these pigments highly increase the NIR reflectance without affecting the visible colour. In addition, they contribute to maintaining the colour characteristics. The application of primer increased the surface temperature, especially for higher exterior temperatures. However, it contributes to a lower colour difference and solar reflectance variation, which is an important achievement for durability purposes

Light source selection for a solar simulator for thermal applications: A review

Solar simulators are used to test components and systems under controlled and repeatable conditions, often in locations with unsuitable insolation for outdoor testing. The growth in renewable energy generation has led to an increased need to develop, manufacture and test components and subsystems for solar thermal, photovoltaic (PV), and concentrating optics for both thermal and electrical solar applications. At the heart of any solar simulator is the light source itself. This paper reviews the light sources available for both low and high-flux solar simulators used for thermal applications. Criteria considered include a comparison of the lamp wavelength spectrum with the solar spectrum, lamp intensity, cost, stability, durability, and any hazards associated with use. Four main lamp types are discussed in detail, namely argon arc, the metal halide, tungsten halogen lamp, and xenon arc lamps. In addition to describing the characteristics of each lamp type, the popularity of usage of each type over time is also indicated. This is followed by guidelines for selecting a suitable lamp, depending on the requirements of the user and the criteria applied for selection. The appropriate international standards are also addressed and discussed. The review shows that metal halide and xenon arc lamps predominate, since both provide a good spectral match to the solar output. The xenon lamp provides a more intense and stable output, but has the disadvantages of being a high-pressure component, requiring infrared filtering, and the need of a more complex and expensive power supply. As a result, many new solar simulators prefer metal halide lamps

Resilient cooling of buildings: state of the art review

Name of the research project : IEA Annex 80 – Resilient Cooling of Buildings Publisher: Institute of Building Research & Innovation ZT GmbH, AustriaThis report summarizes an assessment of current State-of-the Art resilient cooling strategies and technologies. It is a result of a collaborative work conducted by participants members of IEA EBC Annex 80. This report consists of four chapters. In the first chapter are included relevant technologies and strategies that contribute to reducing heat loads to people and indoor environments. These technologies/strategies include Advanced window/glazing and shading technologies, Cool envelope materials, Evaporative Envelope Surfaces, Ventilated Envelope Surfaces and Heat Storage and Release. In the second chapter are assessed cooling strategies and technologies that are responsible for removing sensible heat in indoor environments: Ventilative cooling, Evaporative Cooling, Compression refrigeration, Desiccant cooling system, Ground source cooling, Night sky radiative cooling and High-temperature cooling systems. In the third chapter various typologies of cooling strategies and technologies are assessed inside the framework of enhancing personal comfort apart from space cooling. This group of strategies/technologies comprise of: Vertical-axis ceiling fans and horizontal-axis wall fans (such fixed fans differ from pure PCS in that they may be operated under imposed central control or under group or individual control), Small desktop-scale fans or stand fans, Furnitureintegrated fan jets, Devices combining fans with misting/evaporative cooling, Cooled chairs, with convective/conductive cooled heat absorbing surfaces, Cooled desktop surfaces, Workstation micro-air-conditioning units, some including phase change material storage, Radiantly cooled panels (these are currently less for PCS than for room heat load extraction), Conductive wearables, Fan-ventilated clothing ensembles, Variable clothing insulation: flexible dress codes and variable porosity fabrics. In the fourth chapter technologies and strategies pertinent to removing latent heat from indoor environments are assessed. This group includes Desiccant dehumidification, Refrigeration dehumidification, Ventilation dehumidification, and Thermos-electric dehumidification.Preprin

The effect of cool paints and surface properties of the facade on the thermal and energy efficiency of buildings in a hot and arid climate

The facade of a building is a decisive factor in the thermal and energy performance of buildings. Its surfaces are considered as zones of heat transfer between the inside and the outside. Surface properties, especially color and texture; which have an important role on solar absorption and thermal emittance of the facade and subsequently the thermal operation of the building. The purpose of this article is to study the impact of surface properties of the facade on the thermal comfort and energy efficiency of buildings in a hot and arid climate. The investigation is based on an experimental approach by taking measurements in test cells with an insulating paint (with nanoparticles) as well as on a numerical study by the dynamic thermal simulation software TRNSYS. Several parameters were studied such as ambient temperature, internal and external surface temperature and energy consumption. The results showed that the surfaces of the facade represent with excellence the place of heat exchange between interior and exterior whose surface properties have a colossal impact on the thermal and energy operation of the building. The insulating paint with its nanoparticles has a considerable impact on the reduction of temperature. The proper choice of material absorption has a great influence on the reduction of temperatures and energy requirements of the building