The Polyvalent heat pumps technology in retrofit of existing HVAC systems

In terms of existing buildings’ retrofit, historical and non-residential buildings clearly represent two challenging categories. In historical buildings, due to architectural constraints, acting on the technical side is often the only way to reduce consumptions, while non-residential buildings usually require simultaneous production of hot and chilled water. In these cases, Polyvalent heat pumps represent an interesting solution, able to guarantee significant reductions of primary energy consumptions. In detail, a Reference Building for an historical office was simulated in three Mediterranean cities, using EnergyPlus software and some evaluation tools specifically set to emulate the energy performances of the examined HVAC technologies

HVAC solutions for energy retrofitted hotel in Mediterranean area

To meet the European targets for achieving high-performing buildings, the refurbishment of the existing building stock and, in particular, of historical buildings represents a great challenge. The research aims at identifying the most energy-effective HVAC configuration for retrofitting historical hotels in Mediterranean area, where the objective is to minimize the consumptions for both space heating and cooling. A Reference Building for an historical hotel was simulated in five Mediterranean cities and different HVAC solutions were assessed, using EnergyPlus software coupled with tools specifically set to emulate the energy behaviour of certain HVAC technologies, aiming to highlight the most efficient alternative

Toward NZEB by optimizing HVAC system configuration in different climates

Finding the most appropriate matching between envelope features and HVAC system configurations in function of different climates results fundamental for minimizing buildings’ energy consumptions. The research aims at presenting the most energy-performing HVAC system configurations for high-performing buildings. Different configurations were modeled for new non-residential Reference Buildings in seven European cities, using dynamic simulation software EnergyPlus and some evaluation tools specifically set to emulate the energy performance of some specific HVAC technologies. Finally, the results obtained were compared in order to outline some conclusions, useful as guidelines for optimizing the choice of HVAC systems in function of climate conditions

The importance of recirculation air filtration incontainment of SARS-CoV-2 contagion: the role of photocatalytic filters installed in the fan coils

In containing the contagion of viral diseases transmitted by air, it is essential to reduce the concentration of elementary dose of airborne nuclei present in inhabited rooms, that is reduced by increasing the renewal outdoor air flow, with the same other factor. The increase in the outdoor air flow, however, finds limits due to energy consumption, the maximum generators power required, the ducts size, which are not always compatible with the spaces available, especially in the case of the renovation of existing buildings. The alternative is the filtration of the recirculated indoor air flow. The paper describes possible strategies. Good filtration can always be possible in all-air systems for cinemas, theatres or supermarkets, or in VAV systems, because the AHUs have dimensions and characteristics such as to allow the housing of any type of filter. VAV systems suffer from the defect of spreading the virus in all rooms, while primary air systems leave it confined only where there is the presence of the infected subject, but filtration is necessary through filters installed directly in the fan coil units. In particular, the paper focuses on the studies carried out in the laboratories of the University of Medicine of Padua for photocatalytic filters and shows the results. The most interesting aspect of this type of filter is that they are effective not only on the finer particles that make up the aerosol, but also on the heavier particles deposited on the surfaces of the room

Edifici ad alta efficienza: comfort termico e temperatura operativa

La necessità di risparmiare energia viene sempre più spesso associata a quella di garantire condizioni di comfort termoigrometrico. Si tratta di due obiettivi evidentemente prioritari: il primo per i motivi a tutti noti, il secondo perché il comfort termoigrometrico rappresenta uno degli aspetti del comfort globale, anche detto IEQ (Indoor Environmental Quality), che dovrebbe essere una caratteristica di tutti gli ambienti confinati destinati ad essere occupati dalle persone. Tutto ciò risulta di ancora maggiore interesse quando si parla di edifici a consumo zero, nei quali si potrebbe erroneamente pensare di conseguire il risparmio energetico a discapito delle condizioni di comfort. In questo articolo viene analizzata la problematica relativa alla valutazione delle condizioni di comfort termico in ambienti caratterizzati da valori della temperatura dell'aria diversi da quelli della temperatura media radiante

On the effects of the mean radiant temperature evaluation in the assessment of thermal comfort by dynamic energy simulation tools

The European Directive 844/2018, the EN 16798–1 and –2, and the ISO 17772 Standards establish that when designing a new building or energy retrofitting an existing building, the Indoor Environmental Quality must be considered. One aspect of IEQ is thermal comfort, which is affected by the mean radiant temperature, tr. This variable is the only one that an HVAC system cannot control directly. In fact, it depends on the temperatures of the surfaces surrounding the subject which are influenced by the air temperature. It can be calculated using the methods envisaged by the ISO EN 7726 standard or alternative approximate methods. It is therefore important to understand whether the different tr calculation methods affect the PMV value and,therefore, the classification of the thermal environment according to the EN 16798-1 Standard. For many years, building dynamic energy simulation software tools which integrate energy analyses with the evaluation of thermal comfort have been used for the design and verification of the energy performance of buildings. This paper compares different methods of calculating the mean radiant temperature used by Energy Plus with the Design-Builder interface and analyses the influence of the results on the evaluation of thermal comfort in three buildings