High energy efficiency ventilation to limit COVID-19 contagion in school environments

This study investigates the possibility to contain COVID-19 contagion in indoor environments via increasing ventilation rates obtained through high energy efficiency systems combining thermal recovery by heat exchanger and thermodynamic recovery by heat pump. The starting point of this assessment is a procedure to evaluate in naturally ventilated environments, the current infectious risk by using measurements of indoor/outdoor CO2 concentrations to calculate actual air changes per hour. The method was applied to some typical school environments in Italy. The results indicated very infectious situations with reproduction number Ro values up to exceed 13. But, the simulations assessed an extraordinary reduction of indoor viral concentration and consequently of the infection risk by a strong mechanical ventilation. High ventilation rates make facemasks effective even with use levels (from 50%) reasonable also for pupils. This way, R0 goes down the value one. As regards energy performance, the behavior of an autonomous high efficiency air handling unit (HEAHU), to be installed in an existing naturally ventilated classroom, was simulated in the monitored days. The results highlight the ability to achieve a reduction in energy consumption between 60% and 72%

Impianti innovativi per la riqualificazione di edifici storici

Joining the goal to building energy consumption drastic reduction, acting on today’s natural resources preservation global emergency, is nowadays an authentic challenge which involves national and international applied research. Historic buildings that belong to our heritage, representing our territory cultural structure, trigger lots of unsolved problems in the field of sustainability and energy consumption. The problem dwells on complexity to find a mediation between con-servation needs and energetic update request, to join a satisfying compromise be-tween new law requirements and ancient building reuse with modern functions and historical material minimum transformations. The carried out research activity founds its groundwork in this context. It starts from the regulatory path analysis from the Kyoto protocol (1997) to todays’ interna-tional, national and local laws. These norms started to be simple and general indications on environmental sus-tainability and then they evolved becoming prescriptive guides on energy efficiency improvements redirecting furthermore to existing building heritage. Comparing the energy consumption reduction regulation and the existing building heritage study, it’s evident the complexity in actuating innovation process. This re-search wants to be a methodology stimulus for building heritage. In this field Venetian reality leads us to consider the energy qualification of monu-mental safeguard buildings. Three examples in Venice have been analyzed that respond to these characteristics. The research field was directed to find the most suitable innovative plants by stud-ying the real possibility to join a valid architectonic integration, and to quantify future energetic performances obtained by monitoring the recuperated buildings. The research used two different instruments: the simulation and the system plant monitoring. By the use of dynamic simulation software (Design Builder and Energy Plus) and by the use of built-up software it has been possible to analyze alternative project strategies, to evaluate the project accordance with law standards, pursuing pro-posed solutions energy optimization. Environmental and energetic monitoring has been used as essential instrument to optimize operating plant systems taking advantage of a capillary supervising sys-tem divided in sections. During first research year data regarding relative humidity, the maximum and min-imum winter and summer temperature, the maximum CO2 level (which leads the ventilation modulation and the shutters opening percentage) have been analyzed Next obtained data analysis has permit to evaluate building system and plant sub systems intervention and optimization manners, in real management and using conditions. In the course of time research has been subdivided in the in-depth analysis of three different study cases: 1. The making up of conditioning system plant monitoring installed at “ex Magazzino 6” acquired by University Iuav of Venice, with consequent indi-viduation of possible interventions on working parameters, to reach a net improvement of energy performances and indoor comfort. The after data elaboration, system monitoring given, allowed an energy and economic savings analysis obtainable by a correct management, which optimize in-door humidity and ventilation control, ensuring in any case internal comfort. From this study has been proved that scholar buildings are particularly suitable to reach benefices from a flexible use of relative humidity set point and from a variable ventilation levels, managed from an automatic control based on CO2 sensors. 2. The restoration and plant upgrade of Tolentini ex convent, todays’ University Iuav of Venice headquarter: old classrooms have been transformed to University Library and lecture hall has been renovated. New plants consid-er invertible heat pump use, with geothermal heat-exchanger with vertical boreholes. The project is quite interesting because in a city like Venice, us-ing heating and cooling production machines, it finds obstructions linked to locate either installation permitted areas for cooled air machines or con-densing towers, either using lagoon water, only possible near major canals. The study has been done by building/plant system simulation, which underlined seasonal performance levels always certainly higher than ones obtained by a normal air-water machine. The sensitivity analysis done, in-dicated possible increases of these performance levels using larger sur-face exchange boreholes (double U) and modular machines. Boreholes length increased until 70-100 m (normal depth for mainland realized plants) can reasonably augment performances. Concluding the perimeter is the exchange surface to which point to reach further improvements. 3. Reuse and restoration project analysis of Crociferi Convent, an historical complex in Venice in which University Iuav of Venice realized a campus and University residences. The surface water availability with an adequate renewal circulation due to open lagoon proximity, permitted to foresee in-teresting machine thermal levels. Research activity regarded the preliminary study by simulation. This analy-sis has been done to optimize project choices quantifying energy savings and renewable energy use. The study demonstrated suitable applicative opportunities for invertible heat pump use coupled with lagoon water, that allows to join very interesting seasonal efficiencies: obtainable energetic saving is in fact more than 20% over than traditional plants and clearly higher than the air heat pump obtainable savings

Seawater Opportunities to Increase Heating, Ventilation, and Air Conditioning System Efficiency in Buildings and Urban Resilience

In coastal cities, seawater heat pumps (SWHPs) can combine heat pump technology with the availability of seawater to produce the heat and the cold necessary for heating, ventilation, and air conditioning (HVAC) systems installed in buildings. In heating mode, the seawater is used as a cold source and provides the low-temperature heat needed for the operation of themachine. In coolingmode, the seawater removes the heat dissipated by the condenser of the heat pump working for air conditioning. This seawater application seems to be very promising since the temperature trend of the seawater appears to be more favorable than the alternative use of outdoor air, both in winter and in summer. In a case study in Trieste, the performance of a district heating/cooling network supplied with seawater and based on decentralized heat pumps is investigated. For this purpose, annual dynamic simulations were performed, modeling an urban area, the heat pumps, and the network. The energy efficiency evaluation shows a clear superiority of the SWHP solution compared to boilers and airsource heat pumps and thus the possibility to provide a significant contribution to the decarbonization of buildings. Moreover, the results highlight the ability of this GWHP network to reduce the urban heat island (UHI) phenomenon since the heat dissipated by the heat pumps during summer air conditioning is removed from the urban area. Therefore, SWHPs in coastal cities can be among the mitigation measures for UHI to increase outdoor comfort and heat wave resilience in urban areas

calculation procedure to improve the assessment of photovoltaic generation in solar maps

Abstract The Zero Energy Building (ZEB) target and the higher affordability of photovoltaic (PV) systems are pushing Governments and large Companies operating in electricity generation and distribution network management to develop tools able to better define the potential productivity of PV systems on a large scale, such as solar maps. However, solar maps mainly consider phenomena related to weather and geometry, with a low level of detail on second order effects. This research aims at the integration of additional technical aspects into solar maps, by means of diagrams able to increase the reliability in the assessment of potential electricity generation. For this purpose, more technical factors are taken into account, such as the variation of PV panel efficiency with cell temperature, the shadow cast by the preceding PV panel array, here including the action of by-pass diodes, and the ratio of active area over the area available for installation

natural ventilation level assessment in a school building by co2 concentration measures

Abstract This paper considers the topic of natural ventilation in school buildings that is faced not only for energy saving, but also for the fundamental exigency of the indoor comfort. This analysis is developed by measuring the concentration of carbon dioxide as a significant indicator of IAQ when pollution is mainly due to the presence of people. In this paper are presented the results of a monitoring campaign of the CO 2 levels carried on in classrooms. The measures show the criticality of IAQ with values often much higher than the limits specified by standard, but also the possibility to act effectively with the manual ventilation without excesses that could create comfort problems or waste of energy

Annual Performance Monitoring of a Demand Controlled Ventilation System in a University Library

Abstract Demand controlled ventilation (DCV) is an important opportunity to reduce energy requirement especially in presence of variable occupancy. An evaluation of the possible amount of the energy savings consequent this more flexible control strategy are here presented in a real application case. This refers to the case of an ancient building in Venice. A part of this building was recently transformed in a modern university library. By recording all the measured data from the supervisory system an analysis of the annual performance of the DCV system was carried on. The investigation has pointed out the possibility of remarkable energy savings without compromising internal comfort conditions

application of artificial neural networks to the simulation of a dedicated outdoor air system doas

Abstract Tables of performance of installed HVAC (Heating, Ventilation and Air Conditioning) devices are important in the development of consistent building energy audits and appropriate control strategies. However, given the possible complexity of HVAC devices and the need for the deployment to computational environments, tables of performance should be passed in a more complete and flexible format, compared with the current practices in the HVAC sector. In such a context, this paper describes the phases of development and application of Artificial Neural Networks (ANNs) aimed at the assessment of the performance of a Dedicated Outdoor Air System (DOAS). ANNs are well renowned because of their applications in many important fields such as autonomous driving systems, speech recognition, etc. However, they may be used also to calculate the output of complex phenomena (like the ones involved in HVAC components) and are characterized by a very flexible and comprehensive formulation which would be able to adapt to any HVAC component or system. In the frame of this study, three ANNs have been developed and tested, for the full description of the performance of a DOAS. The developed ANNs were trained by means of data coming from a proprietary software. The achieved ANNs showed robust and reliable behavior and ensure high accuracy (mean absolute errors usually below 0.1 K on temperatures and 0.3% on capacity and power) and flexibility. Moreover, in some cases, they may be used also for the identification of anomalous data present among the sets of training and validation data

development and testing of a platform aimed at pervasive monitoring of indoor environment and building energy

Abstract The interest of the building energy sector is leaning towards the measurement of building actual performance, as regards both indoor environment quality and energy consumption. Sensors and central elaboration units aimed at monitoring indoor environment and HVAC system parameters can also provide the basic infrastructure for further applications such as predictive and neuro-fuzzy controls. However, the cost of such systems is high, so they are mainly used in large buildings. This paper describes the main features and expected applications for a low-budget monitoring platform currently under development and tuning. In particular, the monitoring system was developed based on electronic prototyping platform Arduino and on sensors and devices usually available in the retail market of electronics. The monitoring platform has been designed with the following characteristics in mind: replicability, full remote control, portability, versatility, reliability and affordability

Buone pratiche per la tutela della qualità dell’aria indoor. L’esperienza del Treno Verde 2017

La qualità dell’aria ed in particolare la qualità dell’aria all’interno degli edifici, nell’ambito dei temi relativi a salute e benessere della popolazione, assume oggi, importanza sempre più rilevante. I principali problemi legati alla qualità dell'aria Indoor - IAQ (Indoor Air Quality) - sono strettamente correlati alla concentrazione e definizione dei principali composti inquinanti presenti negli ambienti confinati. L’irrinunciabile tema del risparmio energetico ha prodotto precauzioni che hanno condotto, oltre a un maggior isolamento degli edifici ed a una diminuzione dei tassi di ventilazione, anche all’utilizzo di nuovi materiali e di nuove apparecchiature, cioè a misure che aumentano le concentrazioni di agenti inquinanti che si formano nei locali. Nel corso degli ultimi decenni si è difatti assistito a un progressivo deterioramento della qualità dell’aria negli ambienti confinati. Numerosi studi scientifici hanno dimostrato la presenza, nell’aria degli ambienti di vita, di agenti inquinanti a bassa concentrazione di difficile misurazione che possono determinare effetti sulla salute non ancora completamente noti. Gli inquinanti indoor, che possono agire singolarmente o combinati con altri fattori, determinano una diminuzione del comfort ambientale e un rischio per la salute; sono agenti di tipo chimico (composti organici e inorganici), fisico (radiazioni ionizzanti e non ionizzanti) e biologico (microrganismi, muffe, acari). Considerato che gran parte della popolazione trascorre il proprio tempo in ambienti confinati, l’esposizione all’inquinamento indoor è dominante rispetto a quella outdoor. Vengono considerati come sintomi specifici, non gravi, che possono impattare sulla salute e quindi, sui costi sociali del paese: malattie respiratorie trasmissibili, allergie e asma, sintomi della sindrome dell’edificio malato (SBS, dall’inglese Sick Building Syndrome)

Impianti innovativi per la riqualificazione di edifici storici

Joining the goal to building energy consumption drastic reduction, acting on today’s natural resources preservation global emergency, is nowadays an authentic challenge which involves national and international applied research. Historic buildings that belong to our heritage, representing our territory cultural structure, trigger lots of unsolved problems in the field of sustainability and energy consumption. The problem dwells on complexity to find a mediation between con-servation needs and energetic update request, to join a satisfying compromise be-tween new law requirements and ancient building reuse with modern functions and historical material minimum transformations. The carried out research activity founds its groundwork in this context. It starts from the regulatory path analysis from the Kyoto protocol (1997) to todays’ interna-tional, national and local laws. These norms started to be simple and general indications on environmental sus-tainability and then they evolved becoming prescriptive guides on energy efficiency improvements redirecting furthermore to existing building heritage. Comparing the energy consumption reduction regulation and the existing building heritage study, it’s evident the complexity in actuating innovation process. This re-search wants to be a methodology stimulus for building heritage. In this field Venetian reality leads us to consider the energy qualification of monu-mental safeguard buildings. Three examples in Venice have been analyzed that respond to these characteristics. The research field was directed to find the most suitable innovative plants by stud-ying the real possibility to join a valid architectonic integration, and to quantify future energetic performances obtained by monitoring the recuperated buildings. The research used two different instruments: the simulation and the system plant monitoring. By the use of dynamic simulation software (Design Builder and Energy Plus) and by the use of built-up software it has been possible to analyze alternative project strategies, to evaluate the project accordance with law standards, pursuing pro-posed solutions energy optimization. Environmental and energetic monitoring has been used as essential instrument to optimize operating plant systems taking advantage of a capillary supervising sys-tem divided in sections. During first research year data regarding relative humidity, the maximum and min-imum winter and summer temperature, the maximum CO2 level (which leads the ventilation modulation and the shutters opening percentage) have been analyzed Next obtained data analysis has permit to evaluate building system and plant sub systems intervention and optimization manners, in real management and using conditions. In the course of time research has been subdivided in the in-depth analysis of three different study cases: 1. The making up of conditioning system plant monitoring installed at “ex Magazzino 6” acquired by University Iuav of Venice, with consequent indi-viduation of possible interventions on working parameters, to reach a net improvement of energy performances and indoor comfort. The after data elaboration, system monitoring given, allowed an energy and economic savings analysis obtainable by a correct management, which optimize in-door humidity and ventilation control, ensuring in any case internal comfort. From this study has been proved that scholar buildings are particularly suitable to reach benefices from a flexible use of relative humidity set point and from a variable ventilation levels, managed from an automatic control based on CO2 sensors. 2. The restoration and plant upgrade of Tolentini ex convent, todays’ University Iuav of Venice headquarter: old classrooms have been transformed to University Library and lecture hall has been renovated. New plants consid-er invertible heat pump use, with geothermal heat-exchanger with vertical boreholes. The project is quite interesting because in a city like Venice, us-ing heating and cooling production machines, it finds obstructions linked to locate either installation permitted areas for cooled air machines or con-densing towers, either using lagoon water, only possible near major canals. The study has been done by building/plant system simulation, which underlined seasonal performance levels always certainly higher than ones obtained by a normal air-water machine. The sensitivity analysis done, in-dicated possible increases of these performance levels using larger sur-face exchange boreholes (double U) and modular machines. Boreholes length increased until 70-100 m (normal depth for mainland realized plants) can reasonably augment performances. Concluding the perimeter is the exchange surface to which point to reach further improvements. 3. Reuse and restoration project analysis of Crociferi Convent, an historical complex in Venice in which University Iuav of Venice realized a campus and University residences. The surface water availability with an adequate renewal circulation due to open lagoon proximity, permitted to foresee in-teresting machine thermal levels. Research activity regarded the preliminary study by simulation. This analy-sis has been done to optimize project choices quantifying energy savings and renewable energy use. The study demonstrated suitable applicative opportunities for invertible heat pump use coupled with lagoon water, that allows to join very interesting seasonal efficiencies: obtainable energetic saving is in fact more than 20% over than traditional plants and clearly higher than the air heat pump obtainable savings.Raggiungere l’obiettivo di una drastica riduzione dei consumi energetici negli edifici in base alle attuali emergenze mondiali di conservazione delle risorse naturali e di salvaguardia dell’ambiente, costituisce oggi un’autentica sfida che impegna la ricerca applicata sia in ambito nazionale che internazionale. Gli edifici storici, che appartengono al nostro patrimonio edilizio costituendo l’ossatura culturale dei nostri territori, innescano importanti problematiche irrisolte dal punto di vista della sostenibilità ambientale e del risparmio energetico, proble-matiche legate alla difficoltà di trovare una mediazione tra la necessità di conser-vare e l’esigenza di un adeguamento energetico, per giungere ad una trasforma-zione dell’esistente che sappia soddisfare i nuovi requisiti legati ad un loro riuso per funzioni moderne attraverso però una minima trasformazione della materia storica. L’attività di ricerca svolta trova il suo fondamento in questo contesto e prende l’avvio da un’ analisi del percorso normativo che dal protocollo di Kyoto del 1997 si dirama tra le normative internazionali, nazionali e locali fino ai giorni nostri. Normative che nascono come indicazioni generali sulla sostenibilità ambientale e si evolvono diventando guide prescrittive sul miglioramento dell’efficienza energetica indirizzandosi sempre più sul patrimonio edilizio. Nel giustapporre la normativa sulla riduzione dei consumi allo studio dell’edificato esistente appare evidente la difficoltà di attuare un processo di innovazione, la ri-cerca vuole quindi essere strumento di propulsione per una metodologia che trova il suo oggetto di intervento nell’edificato storico. In questo ambito la realtà veneziana ci porta necessariamente a considerare il problema della qualificazione energetica degli edifici soggetti a tutela monumentale, sono stati a tal fine analizzati tre edifici situati a Venezia e rispondenti a queste caratteristiche. Si è trattato di orientare il campo di indagine al fine di individuare gli impianti inno-vativi più adatti e studiarne la reale possibilità di integrazione architettonica in questi contesti e quantificandone successivamente i le prestazioni ottenute mediante il monitoraggio degli edifici già recuperati. La ricerca si è avvalsa quindi di due strumenti: la simulazione e il monitoraggio del sistema edificio-impianto. Attraverso l’utilizzo di software di simulazione dinamica (Design Builder e Energy Plus) e tramite programmi realizzati con finalità specifiche è stato possibile analiz-zare strategie di progetto alternative, nonché valutare la conformità dei progetti agli standard legislativi e perseguendo in questo modo l’ottimizzazione energetica delle soluzioni proposte Il monitoraggio energetico-ambientale è stato utilizzato come strumento essenziale per l’ottimizzazione del funzionamento di sistemi impiantistici in fase di esercizio e si è avvalso di un sistema di supervisione capillare divisa in sezioni. Sono stati analizzati nel corso del primo anno di ricerca i dati riguardanti l’umidità relativa, le temperature massima e minima estiva e invernale, il tasso massimo di CO2 che comanda la modulazione della ventilazione e l’apertura percentuale delle serrande. La successiva analisi dei dati raccolti ha consentito di valutare le moda-lità di intervento e di ottimizzazione del sistema edificio e dei sottosistemi impianti-stici nelle condizioni reali di gestione e utilizzo . Nel tempo la ricerca si è suddivisa nell’approfondimento e analisi di tre differenti casi studio: 1. La messa a punto del sistema di monitoraggio degli impianti di climatizza-zione installati nell’ex magazzino 6 acquisito da IUAV, con conseguente individuazione di possibili interventi sui parametri di funzionamento, gestiti dalla supervisione installata al fine di raggiungere un netto miglioramento delle prestazioni energetiche e di comfort interno. La successiva elabora-zione dei dati, forniti dal sistema di monitoraggio, ha permesso un’analisi relativa ai risparmi energetici ed economici ottenibili mediante una corretta gestione che ottimizzi il controllo dell’ umidità interna e quello della ventila-zione, assicurando comunque le condizioni interne di comfort. Dallo studio svolto si è rilevato che gli edifici scolastici sono particolarmente adatti a trarre beneficio da un uso flessibile del set-point di umidità relativa interna e da un tasso variabile di ventilazione gestito da un controllo automatico basto su sensori di CO2. 2. Lo studio del progetto di restauro e adeguamento impiantistico dell’ex con-vento dei Tolentini, oggi sede principale dell’Università IUAV di Venezia, per la trasformazione delle vecchie aule presenti in biblioteca di ateneo e il rifacimento dell’aula magna. I nuovi impianti prevedono l’utilizzo di una pompa di calore invertibile con scambiatore geotermico con sonde verticali. Il progetto è di particolare interesse per la ricerca in quanto, in una città come Venezia, l’utilizzo di macchine per la produzione del caldo e del freddo trova spesso ostacoli legati sia al reperimento di aree in cui sia consentita l’installazione di macchine raffreddate ad aria o di torri evaporative, sia all’uso dell’acqua di laguna fattibile solo in prossimità ai canali maggiori. Lo studio svolto mediante simulazione del sistema edificio-impianto ha evidenziato coefficienti di prestazioni stagionali sempre decisamente supe-riori a quelli che si ottengono con la più frequente macchina aria-acqua. L’analisi di sensitività svolta ha indicato la possibilità di incrementare questi coefficienti prestazionali utilizzando sonde con maggiore superficie di scambio (doppia U) e macchine con regolazione modulante. L’aumento della lunghezza delle sonde dell’impianto fino a 70-100 m , valori consueti per impianti realizzati nella terraferma, permette di incrementare decisamente le prestazioni . In conclusione è la superficie di scambio il parametro su cui si deve puntare per ottenere un ulteriore miglioramento. 3. L’analisi del progetto di recupero del Convento dei Crociferi, un complesso storico in Venezia nel quale l’Università IUAV ha realizzato un campus di residenze universitarie. La disponibilità di acque superficiali ,con un'ade-guata circolazione di rinnovo dovuta alla vicinanza dell'edificio con lo spazio lagunare aperto, ha premesso di prevedere livelli termici interessanti per la macchina. L’attività di ricerca ha riguardato lo studio preliminare mediante simulazione. Questa analisi è stata svolta per ottimizzare le scelte progettuali quantificando il risparmio energetico e lo sfruttamento di energie rinnovabili. Lo studio ha mostrato notevoli opportunità applicative per l’uso della pompa di calore invertibile abbinata all’acqua di laguna che permette di raggiungere efficienze stagionali molto interessanti: il risparmio energetico ottenibile è infatti oltre il 20% con riferimento a impianti tradizionali e nettamente superiore a quello ottenuto con la pompa di calore ad aria