Elena Allegrini

Down-Hole Heat Exchangers: Modelling of a Low-Enthalpy Geothermal System for District Heating

In order to face the growing energy demands, renewable energy sources can provide an alternative to fossil fuels. Thus, low-enthalpy geothermal plants may play a fundamental role in those areas—such as the Province of Viterbo—where shallow groundwater basins occur and conventional geothermal plants cannot be developed. This may lead to being fuelled by locally available sources. The aim of the present paper is to exploit the heat coming from a low-enthalpy geothermal system. The experimental plant consists in a down-hole heat exchanger for civil purposes and can supply thermal needs by district heating. An implementation in MATLAB environment is provided in order to develop a mathematical model. As a consequence, the amount of withdrawable heat can be successfully calculated.

Economical Assessment of Large-Scale Photovoltaic Plants: An Italian Case Study

Photovoltaic power is characterized by higher costs than coal-fired technologies. Thus, photovoltaic systems require policy support to become more affordable. This is even more important if the goals -set by Directive 2009/28/EC- must be achieved by 2020. The present paper carefully describes the economical feasibility of a large scale photovoltaic plant, with specific regard to the Italian situation. An Italian case study is investigated and attention is paid to an extremely important tool, i.e. Project Financing. In order to better understand the economical assessment, recent public incentives and supporting measures are taken into account. After analyzing the cash flows and evaluating the Net Present Value (NPV) and the Internal Rate of Return (IRR), the results -obtained by the simulation for different Feed-In Tariff (FIT)s- show that the income is influenced by the date of commissioning and by the amount of incentives.

Use of Semi-transparent Photovoltaic Films as Shadowing Systems in Mediterranean Greenhouses

In Mediterranean greenhouses, active and passive cooling systems are almost always needed due to high values of solar radiation (nearly 1000 Wm− 2) -especially during summer season- and high values of air temperature (near 40°C). Nevertheless, the use of the above-mentioned systems imply the increase of the operating costs of greenhouses.

Italian Residential Buildings: Economic Assessments for Biomass Boilers Plants

Biomass is increasingly used for energy generation since it represents a useful alternative to fossil fuel in order to face the pollutions and the global warming problem. It can be exploited for heating purposes and for supplying domestic hot water. The most common applications encompass wood and pellet boilers. The economic aspect is becoming an important issue in order to achieve the ambitious targets set by the European Directives on Renewable Sources. Thus, the present paper deals with the economic feasibility of biomass boiler plants with specific regard to an existing residential building. An Italian case study is further investigated, focusing the attention on European and national regulations on energy efficiency and considering the recent public incentives and supporting measures. The main thermoclimatic parameters—that is, heating degree days (HDDs), building thermal insulation and thermal needs—are taken into account. Moreover, the following economic indicators are calculated: cumulative cash flow, discounted cumulative cash flow, payback period (PP), net present value (NPV), Internal rate of return (IRR), discounted payback period (DPP), and profit index (PI).

Mathematical Analysis of Gasification Process Using Boubaker Polynomials Expansion Scheme

In this work, a mathematical model of gasification technology has been developed. The aim of the present paper is to analyze the total Gibbs free energy G(U) of the system during the process which strongly depends on the type of biomass CHMON. In order to reach this goal, the Boubaker Polynomial Expansion Scheme (BPES) is exploited as an efficient optimization protocol. The results lead to find out the optimal values for biomass composition and clearly show that the latter and its substrate ratio influence the free energy trend.

Slaughterhouse Wastes: A Review on Regulations and Current Technologies for Biogas Production

In recent years the use of waste biomass for energy generation is becoming an increasingly attractive opportunity, since it leads to several advantages, such as the possibility to eliminate wastes producing energy. As a consequence, the dependence on conventional fossil fuels and global warming can be further reduced. Animal By-Product (ABP) represents a waste produced especially during the slaughter of animals for human consumption, disposal of dead animals and disease control measures. ABPs disposal could lead to high costs and risks for the ecosystem: hence, they shall be used in a sustainable way, minimising health and environmental risks. In the present work, the use of Slaughterhouse Wastes (SHWs) in Anaerobic Digestion (AD) process has been investigated. In Europe biogas production from SHWs must comply with the Regulations No 1069/2009 and No 142/2011 which are carefully described in this study. Furthermore, some previous surveys on AD and co-digestion of ABPs with/without other substrates have been considered and compared in order to fix a starting point for future tests on this subject.