Francesco Fiorito

Forthcoming perspectives of photoelectrochromic devices: a critical review

Re-thinking our relationship with energy resources and environmental equilibrium, towards anthropogenic sustainability, calls for innovative and energetically wise technologies. Smart devices adjusting their optical behaviour depending on the environmental conditions will allow remarkable energy savings. To this end, photoelectrochromic devices (PECDs) have captured, in the last two decades, the interest of many research groups and industrial players worldwide. These devices encompass a dual behavior, being able to generate energy and, concomitantly, deliver a smart optical response. For this reason, they are the ideal skins of future buildings, capable of modulating their behavior in response to changing external stimuli, like sunlight irradiance. PECDs have a wide range of applications, from solar shading in architectural glazing to rear view mirrors in automotives, or avionics. This review article explores the different design concepts standing at the basis of the devices that have appeared so far, shedding light on future perspectives. This work takes into account R&D issues and processing constraints as well as the potential exploitation of emerging solid-state materials promising important technological progress.

A Numerical Study of Turbulent Mixed Convection in a Smooth Horizontal Pipe

This paper presents a numerical study aimed at identifying a suitable turbulence model to describe the fully developed turbulent mixed convention of air in smooth horizontal pipes. The flow characteristics considered here are relevant to those typically observed in ventilated hollow core slab (VHCS) applications and, because of this, the adopted geometry and boundary conditions are represented by the Reynolds number and Richardson number of about 23,000 and 1.04, respectively. Empirical expressions available in the literature are used as reference to evaluate the accuracy of different turbulence models in predicting the dimensionless velocity (u+) and temperature (T+) profiles as well as the Nusselt number (Nu). Among the turbulence models considered, the standard and realizable k-e models provide the best overall predictions of u+, T+, and Nu in the fully developed flow, and the former is recommended for the modeling of VHCS systems as it gives slightly better estimates of the Nu values.

Time series analysis of ambient air-temperature during the period 1970–2016 over Sydney, Australia

Providing evidence of potential changes in the climate has become increasingly important as it is the first step towards adopting mitigation and adaptation measures and planning for urban resilience. In this study a statistical analysis of the ambient air temperature time series over Sydney, Australia during 1970-2016 has been carried out with the aim to investigate potential changes towards higher temperatures. The dataset has been statistically analyzed using different techniques, concluding that the investigation should be performed on a monthly basis. A persistence analysis was conducted using different statistical approaches to investigate the dependence between consecutive monthly and daily ambient air temperature values. A trend analysis of the ambient air temperature and degree days time series has been conducted using linear regression to estimate the linear trend (slope) and its statistical significance (using a Student-t-test) and the Kendall-Mann test to identify the time at which the tendency starts to occur as well as the time after which it becomes statistically significant.

Exploring thermal comfort in the context of historical conservation. A study of the vernacular architecture of Pompeii

ABSTRACT Investigations of the Vernacular Architecture of Pompeii revealed that little work had been carried out on the way the buildings respond to climate and to what extent these buildings were comfortable to the occupant given modern day standards. An integrated methodology from archaeology and architectural science techniques was developed and using a critical case study approach these questions were examined. A case study was selected as representative of the vernacular typology and that was suitably documented from the both methodological perspectives. A computer model was constructed from this data and simulations carried out using weather files from Naples. The findings from the computer simulation suggest that Romans would have been reasonably comfortable in summer; however, in winter the villas would need heating.

A Numerical Procedure for Modelling the Thermal Performance of Ventilated Hollow Core Slabs

This paper presents a numerical procedure for modelling the thermal performance of ventilated hollow core slabs (VHCS). A turbulence model suitable for this purpose is identified first by considering a smooth horizontal pipe subjected to turbulent mixed convention conditions typical of VHCSs. Comparison of the fully-developed dimensionless velocity (u+) and temperature (T+) profiles as well as the Nusselt numbers (Nu) predicted by five different turbulence models against empirical expressions available in the literature shows that the Standard and Realisable k-ε models provide the best overall predictions of u+, T+ and Nu. Since the Standard k-ε model gives slightly better estimates of the Nu values, it is adopted to model the thermal performance of a VHCS geometry for which experimental thermal responses are reported in the literature. The numerical predictions of local temperatures within the VHCS agree well with the experimental measurements, and hence the Standard k-ε model is recommended here for the modeling of VHCSs.

Model analysis of a residential building for demand response

This paper focuses on developing a thermal model in MATLAB that considers both thermal resistance and capacitance in building envelope, using the same assumptions in a building energy simulation tool EnergyPlus to compare the indoor temperature changes between these two, implementing the residential model to find optimal solution for air-conditioning system in smart home energy management systems (SHEMS). The conventional model which is routinely used in the available literature on demand response and home energy management usually neglects the dynamics of a second-order system due to the thermal mass of the house. As a consequence, the energy demand based on the conventional model may be over evaluated. A detailed single family house model was developed using EnergyPlus and the simulation result generated from MATLAB model was compared with the outcome from EnergyPlus. The study shows solar radiation can change the thermal behavior at a noticeable level. Such a less complex model is more amenable to study the effect of thermal inertia in demand response, hence will make the optimization results for scheduling and coordinating distributed energy resources in home energy management more realistic.