Papers by Paolo Valdiserri
Buildings, 2020
Hospitals require the highest energy demands in non-residential buildings. They provide healthcar... more Hospitals require the highest energy demands in non-residential buildings. They provide healthcare 24/7/365 and, at the same time, they ensure indoor air quality, thermal comfort and sterility. However, several studies reveal that high indoor temperatures and low relative humidity (RH) are often perceived in patient rooms during the heating season, suggesting an important energy saving potential. Against this background, radiant ceiling panel (RCP) systems result to be one of the most appropriate solutions as they allow to achieve significant energy savings while providing the highest level of thermal and acoustic comfort, as well as of infection control. In the present study the microclimatic survey of a patient room at Maggiore Hospital in Bologna, Italy, equipped with an air conditioning system integrated with RCP, has reported occupant thermal discomfort. Experimental data were used to calibrate a building model and dynamic building energy simulations were carried out to analyse...
Impianti a pannelli radianti a pavimento negli edifici industriali: Analisi numerica in regime stazionario
Termotecnica, 2003
Analisi tridimensionale dello scambio termico pelle batterie alettate : Confronto fra tubi tondi e tubi ellittici
Termotecnica, 2001
Energy performance of an existing office building in the northern part of Italy: Retrofitting actions and economic assessment
Sustainable Cities and Society, 2016
Building retrofitting is the most feasible and cost-effective method to improve building energy e... more Building retrofitting is the most feasible and cost-effective method to improve building energy efficiency. The paper presents a comparative analysis of two different strategies to enhance the energy performance of an existing building, trying to enhance indoor comfort conditions too. On one hand, the strategy aimed at reducing the heat transfer by transmission, on the other one at decreasing the heat transfer by ventilation. The study has been applied to a school, located in the surroundings of Bologna, Italy. Potential energy savings were calculated by dynamic simulation using Trnsys © software.
This paper describes an integrated passive design approach to reduce the heating demand for an ex... more This paper describes an integrated passive design approach to reduce the heating demand for an existing tertiary building through an improved thermal envelope design and high efficiency windows. The numerical optimization has been performed dynamically by means of TRNSYS simulation tool. The model here treated is aimed at the determination of the thermal demand with reference to a tertiary building in Italy, which it is supposed to be located in two different climatic zones, i.e., Bologna and Rome. The final part of the paper deals with the investment costs analysis, applied to each retrofitting scenario: it has been demonstrated that the simple payback period results to be strongly affected by the climatic zone of the building location and by the national policies of fiscal incentives.
Retrofit Strategies Applied to a Tertiary Building Assisted by Trnsys Energy Simulation Tool
Energy Procedia, 2015
Discharge and Dispersion in Water-Mist Sprays: Experimental and Numerical Analysis
ABSTRACT The present study is aimed at modeling a high-pressure water-mist spray employing two cl... more ABSTRACT The present study is aimed at modeling a high-pressure water-mist spray employing two classic numerical codes. To this end, an experimental campaign has been performed both to obtain the input data for the numerical approach and to serve as a validating tool to quantify the predictive capability of the proposed models. In particular, experi-ments have been conducted to determine volume-flux distribution, drop-size distribution, initial velocity and spray-cone angle. Advanced laser-based diagnostics (Malvern Spraytec and Particle Image Velocimetry) has been em-ployed together with simple ad hoc built instruments to measure these parameters over a prescribed range of high operative pressures (50-90 bar). Specific measurement methodologies have been developed to gain a proper exper-imental evaluation of any subject of investigation. Then, a computational simulation of the water-mist spray has been implemented in Fluent and FDS (Fire Dynamics Simulator) codes. Characteristic drop size, velocity and cone angle have been introduced as input parameters, while volume-flux distribution has been employed to compare numerical results to experimental data as a final validating task. A good qualitative agreement has been gained: the spray physics appears to be properly expressed by the proposed models. However, intrinsic limitations characterize both the experimental tools and the computational codes and may explain some still-to-be-solved discrepancies from a quantitative point of view.
Energy performance of buildings: comparison between a dynamic model and a normalized method
ABSTRACT The European directive 2002/91 introduces some modifications regarding energy performanc... more ABSTRACT The European directive 2002/91 introduces some modifications regarding energy performance of buildings as well as of HVAC systems. Buildings are to be thought as containers where, by a careful planning of the envelope and plants within, the designer ...
Comfort and energy performance of a hvac systems under real conditions for an office block
In the present work, we performed a dynamic simulation of an air-conditioning system for an offic... more In the present work, we performed a dynamic simulation of an air-conditioning system for an office block using a mathematical model via Matlab-Simulink. Both the accomplishment of the desired human comfort within the conditioned space and the variation of energy request due to different measurements of volume flow rate have been evaluated, as requested by the European regulation EN 13779 on non-residential buildings. The model has been applied to an office block located in Bologna (Italy), but can also be used for other types of buildings, as well. The HVAC system in the study uses external air supply, with either constant or variable flow rate, and includes three different ways of air treatment: heating and humidification in winter, cooling and dehumidification in summer, and ventilation only, other ways. The study estimated: i) the conditions that can ensure the requested performances at the lowest energetic cost; ii) the energetic gain deriving from the installation of a heat rec...
Discharge and Dispersion in Water-Mist Sprays: Experimental and Numerical Analysis
The present study is aimed at modeling a high-pressure water-mist spray employing two classic num... more The present study is aimed at modeling a high-pressure water-mist spray employing two classic numerical codes. To this end, an experimental campaign has been performed both to obtain the input data for the numerical approach and to serve as a validating tool to quantify the predictive capability of the proposed models. In particular, experi-ments have been conducted to determine volume-flux distribution, drop-size distribution, initial velocity and spray-cone angle. Advanced laser-based diagnostics (Malvern Spraytec and Particle Image Velocimetry) has been em-ployed together with simple ad hoc built instruments to measure these parameters over a prescribed range of high operative pressures (50-90 bar). Specific measurement methodologies have been developed to gain a proper exper-imental evaluation of any subject of investigation. Then, a computational simulation of the water-mist spray has been implemented in Fluent and FDS (Fire Dynamics Simulator) codes. Characteristic drop size, ...
Experimental Parametric Analysis of Water-Mist Sprays: An Investigation on Coalescence and Initial Dispersion
Volume 6: Fluids and Thermal Systems; Advances for Process Industries, Parts A and B, 2011
Fire Suppression by Water-Mist Sprays: Experimental and Numerical Analysis
2010 14th International Heat Transfer Conference, Volume 5, 2010
ABSTRACT Water-mist systems have become a promising technology in the fire-fighting field over th... more ABSTRACT Water-mist systems have become a promising technology in the fire-fighting field over the last twenty years. The present work is aimed at employing the available knowledge on water-mist sprays in an experimental and numerical analysis of the suppression mechanism. Therefore, a water-mist system has been operated within a typical fire case. Most notably, this latter is constituted by a heptane pool fire: experiments have been carried out inside a test chamber, where a set of thermocouples has conveniently been placed to evaluate the thermal transient at different locations of interest. Some free-combustion tests have been run as a benchmark to validate combustion models. Then, a typical water-mist nozzle has been inserted and activated to realize control, suppression and potential extinction of the generated fire. The recognized FDS (Fire Dynamics Simulator) and Fluent® codes have been challenged in reproducing the test case: thermal transient and suppression time have been considered as parameters for validation. Therefore, the water-mist spray has been modeled and the already mentioned results about its characterization have been implemented as initial or boundary conditions. Moreover, the fire scenario has been modeled as well. A good agreement between experimental and numerical results has been obtained, even under some approximations, with specific reference to combustion mechanisms.
According to recent regulations on energy saving in buildings, all new structures should guarante... more According to recent regulations on energy saving in buildings, all new structures should guarantee high-energy performance. To this aim, the building envelope should be equipped with insulated walls and high-efficiency windows. This approach leads to considerable thermal insulation, but at the same time, in the absence of a suitable ventilation system, it results in a worsening of indoor air quality. A healthy quality of
life requires good indoor air quality; especially in places where people spendmost of their time, adequate air exchanges should be guaranteed and in door pollution reduced to ‘‘acceptable’’ levels. In the present work, we performed a dynamic simulation of a ventilation system for an apartment using a mathematical model, i.e., the Trnsys commercial code. The model has been applied to an apartment of 66 m2 inside a condominium located in Bologna (Italy), but can also be used for other types of buildings as well. The variation of energy request due to different measurements of volume flow rate was evaluated.
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Papers by Paolo Valdiserri
life requires good indoor air quality; especially in places where people spendmost of their time, adequate air exchanges should be guaranteed and in door pollution reduced to ‘‘acceptable’’ levels. In the present work, we performed a dynamic simulation of a ventilation system for an apartment using a mathematical model, i.e., the Trnsys commercial code. The model has been applied to an apartment of 66 m2 inside a condominium located in Bologna (Italy), but can also be used for other types of buildings as well. The variation of energy request due to different measurements of volume flow rate was evaluated.
life requires good indoor air quality; especially in places where people spendmost of their time, adequate air exchanges should be guaranteed and in door pollution reduced to ‘‘acceptable’’ levels. In the present work, we performed a dynamic simulation of a ventilation system for an apartment using a mathematical model, i.e., the Trnsys commercial code. The model has been applied to an apartment of 66 m2 inside a condominium located in Bologna (Italy), but can also be used for other types of buildings as well. The variation of energy request due to different measurements of volume flow rate was evaluated.