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%

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

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

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

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

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

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)