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Natural gas is typically transported for long distances through high pressure pipelines. Such pressure must be reduced before the gas distribution to users. The natural gas lamination process, traditionally adopted for this scope, may determine hydrate formation which may damagingly affect the system operation. Therefore, in order to avoid such circumstance, a suitable gas preheating is required. On the other hand, the available pressure drop can be recovered through a turbo-expansion system in order to provide mechanical energy to drive electricity generators. In this case a higher gas preheating is necessary. This paper presents a detailed simulation model capable to accurately analyse this process as well as the traditional decompression one. Such new model, implemented in a computer tool written in MATLAB, allows one to dynamically assess the energy, economic and environmental performance of these systems, by also taking into account hourly energy prices and weather conditions. Two turbo-expansion system layouts are modelled and simulated. In particular, the gas preheating is obtained by considering two different scenarios: gas-fired heater or solar thermal collectors. Another novelty of the presented dynamic simulation tool is the capability to take into account the time fluctuations of electricity feed-in and purchase tariffs. Finally, a suitable case study relative to a gas decompression station located in South Italy is also presented. Here, a remarkable primary energy savings and avoided CO2 emissions can be obtained through the examined turbo-expansion systems vs. traditional decompression ones. Results show that the economic profitability of the investigated novel technology depends on the available gas pressure drops and flow rates and on the produced electricity use. [ABSTRACT FROM AUTHOR]

In this paper a novel Concentrating Photovoltaic/Thermal Glazing system (CoPVTG), developed at the Centre for Sustainable Technologies of the University of Ulster (Belfast, UK), and exploiting concentration technology, is presented and investigated. The innovative device consists in two glazed panels of which the external one is moulded to form several lenses that concentrate the solar radiation onto photovoltaic cells lines. Thanks to the specific behaviour of these lenses, the solar radiation is capable to reach the indoor environment during the winter months (when it's more useful), while it ends onto the photovoltaic cells during the summer months (reducing the solar gains while also providing electricity to the building). To increase the electricity production, a forced air flux can be created inside the glazed cavity to reduce the PhotoVoltaic cells temperature, and the obtained hot air can be exploited for diverse purposes. Finally, such device is conceived to be integrated into existing windows framing to boost its adoption in new or refurbishment construction. With the intention of studying the device under a wide range of boundary and working conditions, a dynamic simulation tool was developed in MATLAB environment and validated trough experimentally gathered data. With this tool it is possible to investigate the performance of the novel device integrated into several buildings. Specifically, a case study analysis was performed by considering an office building located in five different localities. From the conducted analyses, interesting results and design criteria are obtained. Specifically, the CoPVTG adoption returns higher electricity yield vs. standard semi-transparent window, ranging between 54 and 84% in case of cold and hot weather zones, respectively. In term of overall economic performance, the adoption co CoPVTG allow for a HVAC system running cost reduction, for the investigated case study, ranging from 20 to almost 100% depending on the considered weather zone. • Novel building integrated concentrating photovoltaic thermal glazing system. • Modelling and dynamic simulation of smart building facades for energy efficiency. • Analysis of photovoltaic yield of concentrating and standard solar windows. • Analysis of passive effects of building integrated PV/T glazing systems. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, a purposely designed code for the performance analysis of the Water Loop Heat Pump (WLHP) systems is presented. Hourly, daily and seasonal energy system consumptions, operating economic costs and environmental impact assessments are dealt with. For the scope of comparison, the performances of two reference HVAC system are investigated too. For the computation of the building heating and cooling requirements, a suitable dynamic performance simulation model is being developed. All the relevant algorithms are implemented in MATLAB®. A case study of an office building undergoing simulation in different European climatic areas is being presented. Here, different building thermal features are considered. In order to maximize the system performance an additional optimization procedure to the operating devices temperatures is carried out. Results show that primary energy savings and avoided CO2 emissions of the WLHP system vary in relation to the compared reference systems and can be obtained only in several European weather zones. The feasibility of the WLHP system strongly depends on electricity and natural gas national costs. [Copyright &y& Elsevier]

This paper presents an innovative water photovoltaic thermal collector prototype. One of the main novelties of such system is its economic affordability, obtained through low-cost materials. The collector, constructed and experimentally tested at the University of Patras (Greece), is composed of a polycrystalline photovoltaic module coupled to eleven plastic pipes for water heating, located under the PV panel in an aluminium box. The prototype, suitable for building architectonical integration, can provide domestic hot water and electricity to the building. In order to assess the energy, economic and environmental performance of the system under different weather conditions and for diverse building uses, a suitable dynamic simulation model was developed and validated vs. experimental data. To investigate the convenience of the presented prototype and the potentiality of the developed software, a suitable case study is presented. In particular, the photovoltaic thermal collector is coupled to a stratified hot water storage tank for supplying domestic hot water to a single-family house located in three different European weather zones: Freiburg, Naples and Almeria. The system layout optimization was also performed through an energy and economic sensitivity analysis to some design and operating parameters. Useful design criteria and interesting energy and economic results were obtained. • Development of a novel low-cost photovoltaic/thermal collector prototype. • Development of a dynamic model for thermal and electrical performance assessment. • Experimental validation of the developed simulation model. • Comparative analysis between prototype and commercial collector performance. • Case study analysis for evaluating the prototype energy and economic feasibility. [ABSTRACT FROM AUTHOR]

This paper investigates several actions for the energy refurbishment of some buildings of the University Hospital Federico II of Naples. The analysis focuses on a specific lot of 4 buildings, representative of the whole district hospital. For those structures, sustainable energy savings actions are investigated. They regard the installation of: i) roofs thermal insulation; ii) a substation climatic 3-way valve; iii) radiators thermostatic valves; iv) AHU (air handling unit) time-programmable regulation. This paper aims at presenting an investigation methodology, useful for designers and other stakeholders involved in hospital energy refurbishments, based on an integrated approach which combines dynamic energy performance simulations and experimental campaigns. In order to measure all the simulations' missing input parameters, a suitable experimental analysis, including measurements of temperature, humidity, flow rate and density of construction materials, is performed. A thermographic investigation is also performed for investigating the building envelope performance. This analysis showed that significant savings can be achieved especially by adopting radiators thermostatic valves and AHU regulations. Coherently, the installation of a 3-way valve in the substation does not determine significant additional savings when radiators thermostatic valves are already installed. For high-rise buildings, roofs insulation returns only marginal reductions of space heating and cooling demands. [ABSTRACT FROM AUTHOR]

This paper presents an innovative Concentrating Glazing system to be adopted in smart building façades: The Concentrating Photovoltaic Glazing system (CoPVG). The device consists of a double-glazing panel integrating a series of concentrating lenses. A thin layer of PV cells is then placed at the lenses' focus. The peculiar lens design can produce, by using the Total Internal Reflection (TIR), a seasonal effect with more light entering the building at low incidence angles (i.e. in the winter months) and higher electricity production at high incidence angles (i.e. in the summer months). To investigate this device's performance, a suitable dynamic simulation tool has been developed in MATLAB environment. Furthermore, to investigate active (electric energy production) and passive (building insulation and solar gains variations) effects related to the building integrated devices, the developed CoPVG simulation tool is implemented in a building energy performance simulation one (DETECt). To show the potential of the innovative device, a case study relative to a multi-floor office building integrating the innovative CoPVG prototype is investigated. Conventional and semi-transparent PV windows are also investigated for comparative purposes. By using the novel façade system, interesting energy savings ranging from 30 to 60 % for the investigated weather zones can be obtained. • Novel building integrated concentrating photovoltaic glazing system. • Modelling and dynamic simulation of smart building facades. • Analysis of photovoltaic yield of concentrating and standard solar windows. • Analysis of passive effects of building integrated glazing systems. [ABSTRACT FROM AUTHOR]