Low-E paints enhanced building components: Performance, limits and research perspectives

In the latest years, different solutions have been developed in order to increase the energy performance of opaque building envelopes as far as the heat losses are concerned. Most of them are mainly focused on the bulk properties of materials and are aimed at reaching very low values of thermal conductivity, i.e., super insulating materials. Contemporarily research has been carried out aimed at exploiting the low emissivity in order to reduce the radiative heat transfer between surfaces separated by cavities and, if applied as an internal coating, in order to increase the indoor thermal comfort. In this paper, several solutions that have been experimentally investigated in the latest two years by the authors are presented

Dynamic Insulation Systems: Experimental Analysis on a Parietodynamic Wall

This paper shows the results of an extensive experimental campaign on a ventilated opaque double skin façade based on hollow clay bricks. The winter thermal performances of the dynamic insulated systems were investigated on two different full scale façade configurations through an experimental campaign in double climatic chamber and guarded heat flow meter apparatus. The laboratory tests on dynamic insulated façade (DIF) in both exhaust and supply configurations show respectively an effective reduction of heat losses and the capability of pre-heat the supply air passing across the ventilated external channel. The results confirm the extra insulation offered by the ventilated gap, which allows for a reduction of the wall insulation thickness, providing heat loss reduction and high level of indoor air quality in thin wall constructio

Laboratory Vs Field Performance of Innovative Thermal Insulating Plasters

Thermal insulating plasters and renders are becoming a popular solution for the energy retrofit of existing and historic buildings because of their suitability/compatibility with the existing masonry supports. However, as for most of the insulating products, the actual performance of these materials might significantly differ from the one determined with simplified methods (EN ISO 6946 standard) that are commonly adopted by the designers. In this study, an overview of the latest Authors researches that involve three different thermal insulating plasters, containing respectively perlite, vegetal and aerogel aggregates, are presented. The developed plasters were characterized in the laboratory and successively applied in three demonstration buildings. From the in-field thermal monitoring activities, all the analysed thermal insulating plasters showed a decrease in the thermal performance between 25 and 30% if compared to the laboratory measurements

Thermal Performance Assessment of an Opaque Ventilated Façade in the Summer Period: Calibration of a Simulation Model through in-field Measurements

In recent years, several studies have been performed to evaluate the actual contribute of Opaque Ventilated Façades (OVF) as far as the energy efficiency of buildings in the summer period is concerned. In this framework an experimental real-scale module of an OVF was built and tested. Results demonstrated a reduction of ~58% of the thermal load obtained by using a OVF with respect to the unventilated façade configuration. In this paper the experimental measurements were used to calibrate dynamic simulations using ESP-r software, in order to identify the input factors and the key issues mainly impacting on the results discrepancy

Vacuum Insulation Panels: Analysis of the Thermal Performance of Both Single Panel and Multilayer Boards

The requirements for improvement in the energy efficiency of buildings, mandatory in many EU countries, entail a high level of thermal insulation of the building envelope. In recent years, super-insulation materials with very low thermal conductivity have been developed. These materials provide satisfactory thermal insulation, but allow the total thickness of the envelope components to be kept below a certain thickness. Nevertheless, in order to penetrate the building construction market, some barriers have to be overcome. One of the main issues is that testing procedures and useful data that are able to give a reliable picture of their performance when applied to real buildings have to be provided. Vacuum Insulation Panels (VIPs) are one of the most promising high performing technologies. The overall, effective, performance of a panel under actual working conditions is influenced by thermal bridging, due to the edge of the panel envelope and to the type of joint. In this paper, a study on the critical issues related to the laboratory measurement of the equivalent thermal conductivity of VIPs and their performance degradation due to vacuum loss has been carried out utilizing guarded heat flux meter apparatus. A numerical analysis has also been developed to study thermal bridging effect when VIP panels are adopted to create multilayer boards for building applications

Coupling VIPs and ABPs: Assessment of Overall Thermal Performance in Building Wall Insulation

Super Insulating Materials (SIMs) such as Vacuum Insulation Panels (VIPs) and Aerogel Based Products (ABPs), are characterised by lower thermal conductivities if compared with traditional insulating materials. The objective of the present work is to suggest a new technical solution to reduce the thermal bridging effects in buildings SIMs assemblies. A typological façade where VIPs and ABPs are coupled was numerically analysed to assess the global average thermal transmittance. Moreover results were compared with common solutions based on VIPs coupled with traditional insulating materials (EPS, MDF), considering both thermal and economic aspects

The Effect of Temperature on Thermal Performance of Fumed Silica Based Vacuum Insulation Panels for Buildings

Vacuum Insulation Panels are characterized by very low thermal conductivity, which makes them alluring for building and civil sectors. However, considering the structure and composition of these materials, their application in buildings may be defined by a number of issues which need to be properly taken into account. The real performance of VIPs can be influenced by the boundary conditions (e.g. temperature) at which they work during their operation. In this paper experimental analyses aimed at characterising the relationship between the centre of panel thermal conductivity and average temperature were carried out. The experiments were performed on two VIP samples with different thickness. Moreover a comparison with non-evacuated panels and a traditional insulating material was performed

Thermal bridges in vacuum insulation panels at building scale

In this paper a numerical analysis aimed at evaluating the thermal performance of vacuum insulation panels (VIPs) at the building scale is presented. This technology has seen considerable development over the past few years, gaining increasing penetration in the building insulation market. However, it is important to evaluate correctly the thermal bridging effect that occurs when the VIPs are coupled with joints at the building scale. To this purpose, the linear thermal transmittances of different VIP assemblies inserted in several wall configurations were assessed through a bidimensional numerical analysis. Moreover, to evaluate the influence of thermal bridges on the building energy need, quasi-steady-state simulations for a parametric building module were performed. A simple empirical model was finally built to estimate the linear thermal transmittance from basic input variables. The study demonstrates that thermal bridging effects that occur when VIPs are jointed are never negligible and they could have an important impact on the building heating energy need

Coupled Heat And Moisture Transfer Simulations On Building Components Retrofitted With A Newly Developed Aerogel-based Coating

The study investigates the effectiveness of an energy retrofit strategy based on the adoption of an aerogel-based coating aimed at mitigating thermal bridges and reducing energy losses. The material was developed and characterised in the framework of the Horizon-2020 project ‘Wall-ACE’. The analyses were aimed to validate coupled heat and moisture transfer simulation models at the component level through the comparison with in-field experiments. Furthermore, the results achieved by the heat and moisture simulations were compared with those obtained by means of standardised simplified methods to verify if the adoption of more accurate calculation procedures gives different results