Durability of technologies in the keeping of ZEB's performances

Abstract Durability is an important aspect that has not to be neglected in ZEB design. The requirements for buildings energy needs reduction and increase of renewable energy sources stimulated designers to integrate technologies in an efficient way. This ambitious goal must meet the capacity of the technical solutions to guarantee their performances over the years. The durability of materials and technologies is a topic that warrants further analyses in order to assess the proper efficiencies and the expected lifetime of a ZEB. Typically the energy balance of a ZEB is calculated by considering the annual energy flows or rarely the whole life cycle. The most used approaches consider constant performance of materials and technical elements over the lifespan. However, the performance loss of a single element can cause an imbalance in the behavior of a ZEB, for which persists a thin balance between inlet and outlet flows. The paper provides a critical point of view on this issue paying attention on the following technical solutions implemented in a case study for which the current scientific literature provides analysis on the degradation during their lifetime: glazing systems, VIPs, PV panels and GSHPs

How to control the Indoor Environmental Quality through the use of the Do-It-Yourself approach and new pervasive technologies

Abstract The article describes the results of the "Open-source Smart lamp" aimed at designing and developing a smart appliance that integrates a wireless communication system for building automation, following the maker movement philosophy. The device is able to get an overview of the potential of a nearable device equipped with a variety of sensors to broadcast digital data for the management and control of the Indoor Environmental Quality (IEQ) of the built environment. The Smart Lamp installed in a real office in order to test the reliability of the device in the management of the lighting and air quality levels

Estimation of building energy performance for local energy policy at urban scale

Abstract Cities play a key role in sustainability policies aimed at reducing environmental impacts and increasing energy efficiency in the building sector. At urban level, the analysis models are split in bottom-up and top-down types as a function of the methodological approach of input data processing, aggregated in the first case and disaggregated in the second one. The present paper describes the methodological approach adopted for the implementation of a bottom-up model able to estimate the energy performance of buildings and to define an energy diagnosis process at urban scale. Starting from the information provided by tools available at the Public Authorities and at the most relevant statistical studies on the national energy market, the model provides an estimation of the energy consumption and performance of buildings. The model is applied to a real district of Bologna and the derived spatial database allows the energy performances of buildings to be mapped

A Simplified Thermal Model to Control the Energy Fluxes and to Improve the Performance of Buildings

Abstract The article describes an accurate and suitable simplified tool aimed at evaluating, controlling and managing heat energy fluxes in buildings. The focus is the development of a Resistance-Capacitance (RC) thermal model able to represent the envelope thermal inertia on an hourly time basis. The single RC module simulates the thermal response of a single opaque or transparent element of the envelope. Each module consists of 3 Resistances and 2 Capacitances and is connected to the other modules by thermal nodes and coupled to an air internal temperature node in order to obtain a realistic exemplification of the specific boundary conditions and gains distribution in the conditioned space. The differential balance equations in each node have been solved with an explicit numerical method using Modelica simulation tool. A monitoring campaign was carried out on an outdoor test cell in order to observe the real thermal dynamic behaviour and the real hourly energy needs. The results of the model have been compared with the experimental collected data. The results are presented in terms of temperatures and heating power hourly profiles and cumulative daily energy needs. Finally the Bland-Altmann plot has been used to verify the accuracy and the shortcomings of the proposed thermal model

Application of IoT and Machine Learning techniques for the assessment of thermal comfort perception.

Abstract Thermal comfort is traditionally assessed by using the PMV index defined according to the EN ISO 7730:2005 where the user passively interacts with the surrounding environment considering a physic-based model built on a steady-state thermal energy balance equation. The thermal comfort satisfaction is a holistic concept comprising behavioral, physiological and psychological aspects. This article describes a workflow for the assessment of the thermal conditions of users through the analysis of their specific psychophysical conditions overcoming the limitation of the physic-based model in order to investigate and consider other possible relations between the subjective and objective variables

A multiple linear regression approach to correlate the Indoor Environmental Factors to the global comfort in a Zero-Energy building

The quality of the indoor environment, in terms of thermal, lighting, air and acoustic quality, grouped in the Indoor Environmental Quality (IEQ) concept, plays a key role in occupants’ wellbeing and satisfaction. Only in recent years IEQ has been investigated as a whole. Today, IEQ occupies the same place of energy efficiency in the design of buildings, especially those with high performance level as the Zero-Energy Buildings (ZEB). The research deals with an experimental campaign during the cooling season carried out in a ZEB laboratory that involved 100 participants aimed at evaluating the IEQ and the indoor environments (e.g. thermal and air quality). The test consists in a survey, during which each participant is required to answer a questionnaire about how he feels the indoor environment. The experimental campaign was completed with a monitoring activity aimed at detecting the main environmental variables that can affect the participants’ answers. Collected data were treated with regression techniques to highlight possible relationships between them. The results show how in a building with high levels of energy performances the air quality plays a key role on occupants’ evaluation

An Integrated Framework for Users’ Well-Being

The hygro-thermal comfort (ICQ) is defined as the psychophysical state in which the subject expresses a condition of well-being with respect to environmental variables, a condition known as thermal neutrality. Furthermore, the ICQ represents one pillar of the holistic concept of the Indoor Environmental Quality (IEQ). The methods for the assessment of ICQ and recognized at international level are mainly two. The former, based on a steady-state approach, described by the EN ISO 7730:2005 and applied to Fully Mechanically Controlled buildings (FMC) equipped with an active conditioning system. The latter, based on an adaptive approach, as defined trough in field activities and described by the technical standard ASHRAE 55 and EN 15,251, instead, considers the users as active subjects that interact with surrounding environment and are influenced in their comfort perception by external conditions. In this case, the thermal comfort concept is not just defined depending on physical, but also psychological, social, economic and cultural aspects. The technical standards provides that this method could be applied in middle seasons when the control of comfort is handled by passive technological methods, i.e., in the so called Natural Ventilated or Free Running buildings (FR). In this approach, methodologies providing the direct involvement of the end user are consolidating, through the collection of physiological, psychological and behavioral personal data as to obtain the better assessment of the comfort conditions. Placing in this field, the article describes the results of a field investigation in an office aimed at defining a framework for the assessment of the thermal comfort based on the two approaches through the use of low cost technology solutions, parametric and freeware models

A Low-Cost Environmental Monitoring System: How to Prevent Systematic Errors in the Design Phase through the Combined Use of Additive Manufacturing and Thermographic Techniques

nEMoS (nano Environmental Monitoring System) is an all-in-one, low-cost, web-connected and 3D-printed device aimed at assessing the Indoor Environmental Quality (IEQ) of buildings. It is built using some low-cost sensors connected to an Arduino microcontroller board. The device is assembled in a small size case and the integrated air temperature and relative humidity sensor and the globe thermometer could be affected by thermal effect due to overheating of some nearby components. A thermographic analysis was made to rule out this possibility. The paper shows how the pervasive technique of Additive Manufacturing can be combined with the more traditional thermographic technique to redesign the case and to verify the accuracy of the optimized system in order to prevent instrumental systematic errors in terms of difference between experimental and actual values of air temperature, relative humidity and radiant temperature

A Low-Cost Environmental Monitoring System: How to Prevent Systematic Errors in the Design Phase through the Combined Use of Additive Manufacturing and Thermographic Techniques

nEMoS (nano Environmental Monitoring System) is a 3D-printed device built following the Do-It-Yourself (DIY) approach. It can be connected to the web and it can be used to assess indoor environmental quality (IEQ). It is built using some low-cost sensors connected to an Arduino microcontroller board. The device is assembled in a small-sized case and both thermohygrometric sensors used to measure the air temperature and relative humidity, and the globe thermometer used to measure the radiant temperature, can be subject to thermal effects due to overheating of some nearby components. A thermographic analysis was made to rule out this possibility. The paper shows how the pervasive technique of additive manufacturing can be combined with the more traditional thermographic techniques to redesign the case and to verify the accuracy of the optimized system in order to prevent instrumental systematic errors in terms of the difference between experimental and actual values of the above-mentioned environmental parameters