Sonia Longo

Is the NZEB Benchmarking Approach Suitable for Assessing Energy Retrofit Design

Currently, many effort have been done to enable energy saving issues in building design and many definitions have been introduced for most performing constructions based on energy balance between energy demand and supply. Recently, the Net Zero Energy Building theory has bypassed old Passive House concept but many questions still remain open. Present work aims to estimate how NZEB requirements matching could be affected by the choice of their definition and the choice of weighting factor system, to be count in the energy balance. NZEB concept is mainly referred to new buildings design. Its application to existing buildings is for sure an hard task provided the architecture and physical constraints are often problematic. Nevertheless, the benchmarking approach able to assess the building performance according to the NZEB objective can be utilized for other two purposes. The first one is to assess how an existing building is far from the performances of a NZEB. The second one is to assess the contribution of a conventional retrofit in improving its energy balance.

Energy-related GHG emissions balances: IPCC versus LCA

Addressing climate change is one of the greatest environmental challenges. Due to the impact of cities to energy consumption, the involvement of the local authorities in environmental policies is rapidly increasing. The Covenant of Mayors (CoM), launched by the European Commission, is an urban initiative aimed at reducing CO2 emissions. The signatories have to compile the greenhouse gas emissions (GHG) balance of their territory and, to do so, they can use the Intergovernmental Panel on Climate Change (IPCC) or the Life Cycle Assessment (LCA). Moreover, the signatories have to define strategies to reduce the GHG emissions. In this context, authors estimate the GHG balance of an Italian municipality using both methodologies in order to compare the results. In detail, the first application is the IPCC, the second one is the LCA approach for which two cases are analysed: i) LCA with fossil fuels and electricity GHG emission factors based on the European Reference Life Cycle Database, LCA (I); and ii) LCA with a site - specific GHG emissions for electricity generation, LCA (II). They propose energy strategies in order to quantify the achievable GHG emissions reduction by the exploitation of the renewable energy resources. The study shows that the GHG emissions results obtained with the LCA approach are higher by 20% than those calculated with the IPCC approach. This difference is relevant and it could be significant in identifying effective climate strategies. The LCA methodology ensures a systemic accounting of emissions, then, it can be more effective in order to achieve GHG emissions reduction at global level. The examined energy strategies allow for reducing the GHG emissions of about 7% of the total reduction required by the CoM. This confirms that a preliminary evaluation of the strategies is useful for the allocation of the financial resources to the environmental policies.

Ventilative cooling application in Mediterranean buildings: impacts on grid interaction and load match

ABSTRACT The concept of load matching refers to the simultaneous occurrence of loads and generation in buildings: it can be increased and optimised with modifications on both the energy demand and generation, but its pre-requisite is to guarantee passive energy efficiency. In the Mediterranean areas, a major challenge in new buildings is the increasing overheating even during mildly hot seasons. Ventilative cooling can be a potential solution to such issues and have an impact on load match in buildings and their grid interaction. The study analyses the potential of ventilative cooling to improve the load match in three different case studies in Italy. Ventilative cooling proved viable in moderately improving the load match and in more effectively reducing import of electricity from the grid under the appropriate climatic\indoor conditions. In addition, the thermal-physical features, energy generation and consumption characteristics of the buildings are a source of large variability in the results. Increases in the load cover factor through natural ventilative cooling among the case studies range from 0.5% (high-performance building, low cooling share) to 5% (prefabricated module, high cooling share on the total); energy import is reduced effectively from 1% up to 22% in the case of a Sicilian residential building.

Energy planning methodology of net-zero energy solar neighborhoods in the Mediterranean basin

The article proposes a simplified methodology to optimize solar energy gains at district level in the Mediterranean area toward the achievement of the net-zero energy district target, to be applicable as well in similar hot climates. The approach includes a wide use of parametric analysis to explore the most impactful aspects of the design of solar net-zero energy districts: single unit shape, building mutual distances, road shape, building orientation, photovoltaics area availability to identify the optimal design solution. Thirty-two different district configurations are explored: results show that in the Mediterranean context, it is possible to reach the net-zero energy district target in several configurations investigated; however, cooling energy requirements can vary up to 20% in the different combinations examined. In a context of high demographic growth and consequently of expected rise of housing demand especially on the southern side of the Mediterranean, the proposed method can be useful in the application of bioclimatic concepts to large scale energy planning and energy policies as well for practitioners and building designers.

The Use of Genetic Algorithms to Solve the Allocation Problems in the Life Cycle Inventory

One of the most controversial issues in the development of Life Cycle Inventory (LCI) is the allocation procedure, which consists in the partition and distribution of economic flows and environmental burdens among to each of the products of a multi-output system. Because of the use of the allocation represents a source of uncertainty in the LCI results, the authors present a new approach based on genetic algorithms (GAs) to solve the multi-output systems characterized by a rectangular matrix of technological coefficients, without using computational methods such as the allocation procedure. In this Chapter, the GAs’ approach is applied to an ancillary case study related to a cogeneration process. In detail, the authors hypothesized that there are the following multi-output processes in the case study: (1) cogeneration of electricity and heat; (2) co-production of diesel and light fuel oil; (3) co-production of copper and recycled copper. The energy and mass balances are respected by means of specific bonds that limit the space in which the GA searches the solution. The results show low differences between the inventory vector derived from the GA application and that one obtained applying the substitution method and the allocation procedure based on the energy content of the outputs. To avoid the allocation, the application of GA to calculate the LCI seems to be a promising method.

Benefits of Refurbishment

Energy and environmental performances of buildings strictly depend on many factors related to the choice of construction materials, HVAC plants and equipment, design, installation and use. By definition, a building interacts closely with its environment. The interactions between building and climate, plants and users have to be taken into account. This aspect is evident in new buildings design process, but it is even more important in the design phase of an existing building renovation, during which actions of energy saving are developed. This chapter summarises the results of the energy and environmental assessment of a set of retrofit actions implemented in the framework of the EU Project ‘BRITA in PuBs’. The main goals were to improve building energy and environmental performances following a life-cycle approach and to support the project partners to select the retrofit actions involving the highest energy saving and the lowest environmental impacts. Synthetic indices, as energy and GWP payback times, and energy return ratio, are defined to better describe the energy and environmental performances of the actions. The use of the life-cycle approach was very successful and potentially transferable to other contexts of building retrofit study.

Energy and Environmental Assessment of Retrofit Actions on a Residential Building

Energy and environmental performances of buildings strictly depend on many factors related to the choice of construction materials, technical equipment, installation and use. In the following chapter a set of retrofit actions to improve the thermal performance of an existing conventional building is presented. The energy and environmental assessment of these actions is carried out following a life cycle approach. The embodied energy and the environmental impacts arisen from the production, transportation and installation phases of the required materials and components are calculated. Further, energy saving and environmental benefits and drawbacks concerning the assessed retrofit actions are accounted for.

Refurbishment Scenario to Shift Nearly Net ZEBs Toward Net ZEB Target: An Italian Case Study

The idea of a Net ZEB arises from the development of design criteria and construction methods, addressed to curb the operating energy, increasing the energy efficiency of building equipment and appliances, and of the thermal insulation of envelope components, and enhancing the on-site energy generation, by means of renewable energy sources, to cover the annual building energy loads. In this chapter, the energy and environmental performances of an Italian nearly Net ZEB following a life cycle approach are carried out. Then, a scenario of refurbishment is foreseen in order to shift the studied building from the nearly Net ZEB condition toward the Net ZEB target, and the arising energy and environmental benefits are assessed. The life cycle approach in the energy and environmental assessment of the foreseen retrofit options is necessary to avoid shifting environmental burdens from one step of the life cycle to another. Further, in order to get a deeper description of the energy performance of the retrofit actions and to compare the different alternatives, the energy payback time (EPT) and the emission payback time (EPT) are assessed for the proposed solutions.

Life Cycle Assessment of Solid Oxide Fuel Cells and Polymer Electrolyte Membrane Fuel Cells: A Review

Abstract Fuel cells (FCs) are among the key technologies that Europe will have to rely on in order to comply with the most recent environmental targets inspired by decarbonization and circular economy. The assessment of the real advantages of using FCs for producing energy must include a reliable analysis of the energy and environmental impacts during the life cycle of these systems, including the raw materials supply, production, use, and disposal. In this context, the life cycle assessment (LCA) is a well-established methodology for assessing the eco-profile of products and services and for identifying the components and the life cycle steps having the largest contribution to energy and environmental impacts. In the chapter, authors focus on the analysis of two types of FCs: solid oxide FCs and polymer electrolyte membrane FCs. Authors describe the FC technology, the sectors of application, and the FC materials and components. A literature review of available LCA researches is also discussed to point out the environmental impacts of the FCs and the methodological issues that can arise in the study of a FC.

Mobility scenarios in the valley of the temples

The valley of the Temples in Agrigento is one the most known wonders of the ancient Greek time to be still standing is South Italy. Chosen as an emblematic location in the center of the island, it is the exemplary site used to assess the potential for electric mobility in terms of energy and environmental benefits of electricity over standard fuels. Such an assessment is performed by means of a life-cycle approach, including the use of the Life Cycle Assessment methodology, the use of the standard ILCD-PEF indicators and the development of a parametric analysis investigating the impact of different electricity penetration levels in the local transports system. The results identify relevant energy savings in the electricity mobility scenarios (5-6%) as well a mixed trend for the environmental impacts: some indicators would show some relevant reductions (e.g. -70% for GWP) but others would grow as relevantly (e.g. +50% resource consumption for PV generated electricity). The research is developed in the context of the project Innovation for greeN Energy and eXchange in Transportation (i- NEXT).