Analysis of the coupled effect of steel studs and surface emissivity on internal insulation systems performance

Many kinds of insulation systems have been developed and applied over the years to all the constructive elements of the building, but the two most used strategies remain the external and internal insulation of vertical walls. However, about the latter often a significant issue is neglected: the overestimation of the thermal performance by disregarding the contribution of construction elements. Usually a uniform stratigraphy of the wall is considered and the evaluation of the performance of a non-uniform one leads to erroneous results about the overall behavior of the system. In this paper, we developed a different approach considering the presence of the steel studs used to attach this package to the existing wall and their influence on the thermal behavior of the structure. Through both experimental and numerical analysis, the possible application of low-e sheets inside the air cavity in various configurations and with different thicknesses of insulation is also taken into account. Results showed that neglecting the presence of the steel studs leads to an erroneous evaluation of the conductance of the refurbished wall with errors reaching up to 28.0% in low-e high-insulated cases. This work highlights how careful the designers have to be when using standard formulas to compute the thermal resistance of internal insulation wall systems

genetic optimization for economic feasibility of refurbishment in buildings

Abstract This paper investigates the possibility to enhance the thermal characteristics of a building fabric taking into account the economic feasibility in order to avoid useless expensive interventions. The problem consists in realizing an internal insulation system for a single apartment located in Trieste. A genetic optimization has been implemented in order to search a large number of solutions with multiple objects and constraints. EnergyPlus has been used for dynamic building and plant simulation and modeFRONTIER for optimization loop setup. The objectives are the used heating energy consumption and the life cycle refurbishment cost, using a net present value approach. An additional objective has been added in order to guarantee the maximization of the interior useful floor area, which is directly influenced by the internal insulation thickness. Different approaches have been compared, considering actions dealing with opaque surfaces only or considering the replacement of existing windows. The paper demonstrates that an automatic optimization approach can help designers to identify the best suited intervention for building refurbishment

Development of a Stratified Tank Storage Component for Esp-R with Embedded PCM Modules

Solar domestic hot water systems (SDHW) are very common and are considered an efficient system for exploiting the renewable energy source of the sun, for instance national Italian regulations require the adoption of SDHW systems in new buildings. Water tanks are typical components for such systems, but have a serious drawback since they require a great amount of space in the building. In this paper a new water tank model for the ESP-r code is presented. A new feature has been added to an existent tank model, that is the possibility to include internal Phase Change Materials (PCM) modules. The paper describes the numerical model used to deal with phase change phenomena and the incorporation of the method into the ESP-r source code. The inputs and parameters required to describe the new component are presented as well. To validate the model the results of a test case have been compared with literature data. A typical SDHW system has been simulated in order to study the impact of the PCM modules inside a tank on the energy performance of the system. Two tank sizes have been used to verify the impact of the modules. The results are reported using a global parameter that represents the fractional primary energy saved by using the solar system. Temperature plots with and without PCM have been reported as well

Monitoraggio di un edificio a basso consumo energetico a Trieste

Data la grande importanza che sta assumendo il risparmio energetico in edilizia si \ue8 deciso di monitorare per circa un anno e mezzo un edificio a due piani a basso consumo energetico costruito nella periferia di Trieste con esposizione a sud ovest per poter rendersi conto degli effettivi consumi, sia invernali che estivi, e del funzionamento dell\u2019impianto geotermico e aeraulico dell\u2019edificio stesso. Questi dati verranno in una fase successiva dello studio confrontati con quelli ricavati da un analisi dinamica dell\u2019edificio. L\u2019impianto \ue8 costituito da una pompa di calore geotermica che alimenta pannelli radianti a pavimento con funzione, sia di riscaldamento invernale, che di raffrescamento estivo. \uc8 presente anche un impianto di ricambio d\u2019aria forzato con recuperatore di calore. Sono, inoltre presenti pannelli solari termici e fotovoltaici. Tramite un sistema di acquisizione National sono state acquisite le temperature di mandata e ritorno di tutti i circuiti e le relative portate. Inoltre sono state acquisite le temperature del terreno a contatto con i due pozzi geotermici, le temperature dell\u2019aria di rinnovo e la potenza elettrica consumata dalla pompa di calore. In questo lavoro verr\ue0 descritto il sistema di misura e saranno analizzati i risultati energetici ottenuti

Energy Measurements for a low Energy Building in Trieste

ENERGY MEASUREMENTS FOR A LOW ENERGY BUILDING IN TRIESTE In view of the importance of energy savings in buildings constructions a two floor low energy building has been monitored for over one year and an half, with the aim of recording the energy consumption both in winter and summer seasons. An additional outcome of the project is to collect information about the performance and behavior of the system plant featuring a geothermal heat pump, photovoltaic system, domestic home solar water and heating integration. The building with a south west exposition is conditioned by a radiant floor system for both heating and cooling and is provided with forced air system ventilation with recuperator, to avoid condensing problems during cooling periods an automatic dehumidification system is provided as well, heating and cooling are provided by a geothermal heat pump system. During the research, thanks to the deployment of a National Compact RIO data acquisition system, a great mount of data have been collected. The data comprises the temperatures and flow rates of all the hydronic circuits, ground temperatures in the boreholes, air temperatures in correspondence of the recuperator, electric consumption of the heat pump and of the whole plant system. The collected data will be in future used to compare the results of a dynamic simulation of the building. In this paper the acquisition system and the energetic behaviour of the building in summer and winter seasons will be presented

Utilizzo di sistemi di simulazione dinamica per l'analisi energetico-economica di un edificio ad uso servizi: strategie per il miglioramento energetico

Nel presente lavoro viene utilizzato un sistema di simulazione dinamica, ESP-r, per analizzare approfonditamente l\u2019impatto di una serie di interventi da intraprendere per la ristrutturazione di uno stabile industriale ormai in disuso. L\u2019ipotesi di recupero prevede l\u2019utilizzazione dell\u2019edificio nel settore terziario come sede di una societ\ue0 di progettazione. Tale intervento ha richiesto un\u2019accurata analisi del comportamento dell\u2019edificio oltre che nel periodo invernale anche nel periodo estivo, infatti gli elevati carichi termici dovuti alla presenza di apparecchiature elettroniche hanno richiesto un\u2019accurata analisi in questo ultimo periodo. Sono stati individuati diversi interventi possibili per la riduzione del fabbisogno di energia. Il primo intervento ha previsto la coibentazione dell\u2019involucro e la sostituzione degli elementi finestrati, pertanto sono state considerate due soluzioni, una corrispondente al soddisfacimento dei limiti imposti dal decreto 311, l\u2019altra con caratteristiche di isolamento pi\uf9 spinte tipiche delle case passive. \uc8 stato quindi possibile confrontare i risparmi energetici ottenuti rispetto alla soluzione non isolata iniziale. Grazie alla simulazione dinamica sono state individuate le criticit\ue0 delle soluzioni proposte specialmente per quanto attiene al periodo estivo, analizzando quindi due soluzioni per l\u2019abbattimento dei carichi estivi: sistemi schermanti esterni e ventilazione notturna. L\u2019impatto di tali interventi \ue8 stato accuratamente analizzato evidenziandone l\u2019impatto sul bilancio energetico, non trascurando anche gli aspetti economici. L\u2019analisi energetica effettuata ha rappresentato la base di partenza per un successivo lavoro riguardante le soluzioni impiantistiche adottabili