Costs Assessment for Building Renovation Cost-optimal Analysis

AbstractIn the frame of the IEA-EBC project “Cost-Effective Energy and Carbon Emissions Optimization in Building Renovation”, the Politecnico di Milano research group elaborated the information required to perform the renovation measures cost-optimal analysis of two case study buildings, representative of the most common ones of the Italian residential stock. Renovation costs have been composed accurately and, additionally, an analysis of several references has been accomplished for collecting national energy consumptions and GHG emissions values, current and projected, and energy career indexes. Adopted approach can provide insights for analogous researches and outcomes can be considered for similar retrofit cases in Italy

Renovating Building Groups in the Mediterranean Climate: Cost-Effectiveness of Renewable-Based Heating Alternatives in the Italian Context

District level approaches for the renovation of the building stock boost the implementation of energy efficiency measures (EEMs), taking advantage of the economies of scale. International Energy Agency Annex 75 aims to assess the cost‐effectiveness of renovation strategies at the district level, combining EEMs and renewable energy sources. For this goal, a building energy model is simulated with the Energy Plus dynamic calculation engine for assessing the generic district of the Italian case study, representing the residential stock from 1960 to 1980, placed in two prevailing space‐heating dominated climates; then, a cost‐effectiveness evaluation of each scenario is conducted to support stakeholders’ decision making. In particular, envelope insulation is cost‐effective only in northern zones, while new decentralized thermal systems are not convenient in any case with current envelopes. Once the envelopes are insulated, decentralized low‐temperature air‐towater heat pumps with PV can cover all of the buildings’ energy needs, even implying a small increase in annual costs. The switch to district net scenarios is cost‐effective only if coupled with PV. A rise in energy prices brings PV‐based strategies under a 10‐year PBT, except for solar thermal DH in northern areas, as well as non‐PV‐based options such as low‐temperature HPs or biomass‐fuelled DH in warmer and colder zones, respectively

Cost-effective building renovation strategies at the district level combining energy efficiency & renewables – investigation based on parametric calculations with generic districts

Informe generado en el marco del Energy in Buildings and Communities Programme de la International Energy AgencyThis report aims to study cost-effective strategies to combine energy efficiency measures and renewable energy use in building renovation at the district level and to investigate factors influencing the choice of a cost-effective strategy. This is done through generic district assessments, where hypothetical, “generic” districts are generated to model typical conditions in various European countries. For the generic districts, relevant variables were defined to carry out parametric assessments, applying and testing the methodology developed in IEA EBC Annex 75. The generic districts were generated and selected based on the typical conditions in each country, and the hypothetical nature of the assessment allowed for studying different starting conditions and renovation measures. It is, in particular, investigated to what extent there are synergies and trade-offs for combining energy efficiency measures and renewable energy measure

Results of a literature review on methods for estimating buildings energy demand at district level

In the framework of distributed energy planning, evaluating reliable energy profiles of different sectors has a prominent role. At the same time, it is a quite challenging task, since the availability of actual energy profiles of buildings at the district level is not widespread. A survey of over 70 studies in scientific literature has been accomplished and a set of criteria has been defined for classifying the selected contributions based on the energy demand data features, source and/or estimation methods, highlighting the ones adopting hourly energy profiles. As final results, tables summarizing the main methods characteristics and a selection of studies providing directly useable energy profiles are reported. Therefore, this study could be useful for stakeholders involved in energy simulations of buildings stocks and community energy planning in assessing the buildings energy demand, with different desired level of detail and available data. The research, broadly, demonstrates that the potential replicability of analysed methods is constrained to the datasets availability and, particularly, highlights the need of reliable hourly energy profiles definition for developing accurate energy scenarios

Assessing Buildings Hourly Energy Needs for Urban Energy Planning in Southern European Context

AbstractFor decreasing the fossil fuels consumption and reducing air pollution at urban level, current policies encourage a transition to distributed energy generation (DG) and support initiatives towards district heating and cooling networks (DES - district energy systems), promoting the integration of renewable energy sources (RES). Based on these approaches, the assessment of the energy demand fluctuations of the building stock is preliminary for energy planning at district scale, since systems’ operation requires a complex balancing for maximizing the efficiency or minimizing the cost, combining the intermittent nature of RES (except biomasses) with non-RES and/or storage technology. Surveyed literature concerning recent studies aimed at optimizing district energy scenarios revealed that most of the assessment are limited to the seasonal and/or annual based buildings energy needs, while the ones that deal with a proper time scale (i.e. hourly based) refer to specific case studies, which are hardly replicable in other urban contexts. The purpose of the study presented in this paper was to provide reliable reference profiles of buildings thermal energy needs (for both space heating and cooling) with reference to the Italian context. Therefore, a set of building models, representative of typical solutions of different historical periods, was defined for both residential and diffuse tertiary (offices) use. Once elaborated accurate hourly internal loads curves, it was possible to provide, performing detailed simulations with TRNSYS model, profiles of energy need density, referred to cubic meter of building volume, for typical buildings placed in different climatic locations, covering the wide range of Italian context. Based on both the building typologies and the climatic variability considered, assumptions adopted for the study could be extended to other comparable context in southern Europe

Mapping Buildings’ Energy-Related Features at Urban Level toward Energy Planning

To boost energy efficiency in the building sector at urban and district scales, the use of a Geographic Information System (GIS) for data collection and energy spatial analysis is relevant. As highlighted in many studies on this topic reported in literature, the correlation among available databases is complex due to the different levels of information. As the first part of a wide research aimed at estimating the energy demand of urban buildings, we present in this article a focus on the details of the GIS-based procedure developed to assess the main energy-related features of existing building stocks. The procedure is based on the elaboration of data from the Italian Topographic Databases, under provision at the national level according to the INSPIRE European Directive and the national General Census of Population and Houses. It enables one to calculate and map the urban built volume characterized by mostly diffuse use categories in an urban context (residential and offices), to which different equipment and building usage patterns can be associated, and by construction periods, featuring different technological solutions. The method has been applied to the city of Milan (Italy). An insight into the outcomes from the overall method of the wider research is also reported

Accurate and user-friendly tools for local energy planning

For low carbon district/urban energy planning, several computational tools have been developed although guidelines for a more diffuse use in common planning out of the academic ambit are needed. We first assessed 17 selected easy-access and well documented tools based on: analysis type, operation spatial scale, outputs time scale, use and licence. Hence, we identified 6 tools that enable both energy calculations and outputs visualization on hourly base and can be considered as viable of widespread use. General information, functionalities, structure, graphic user interface, required input data and outputs were described. A plenty of information is provided on the data quality and level of details and the related constraints to implement an energy system analysis. The possible final user is guided in choosing the tool based on the related outputs and potentialities, but also on available data for a given context and the required skills

Mapping Seasonal Variability of Buildings Electricity Demand profiles in Mediterranean Small Islands

In communities with a high tourist influx and warm climate, such as Mediterranean small islands, the energy demands for space cooling and domestic hot water are expected to significantly increase during summer. Considering the current energy context, for succeeding energy transition and reducing the dependency on not endogenous fossil fuels, it is paramount to increase the deployment of renewable sources of energy, especially wind and solar which, however, are aleatory and unpredictable. Hence, to reduce the high costs for energy supply in these contexts, the analysis of the variation of energy consumption is fundamental. Moreover, mapping the spatial distribution of energy profiles can be useful to have an overview at a large scale of the considered building stock. Within this frame, a Geographic-Information-System-based procedure was implemented to estimate the residential buildings energy demand profiles, focusing on the seasonal variation. The adopted method can provide a valid supporting tool for decision makers that have to implement smart energy strategies in contexts with a high variation of the energy demand and evident electricity summer peaks. The method for mapping the energy demand profiles, implemented on the small island of Pantelleria, can be applied to other similar contexts, also supporting energy policies in the implementation of renewable energy communities

Mapping Seasonal Variability of Buildings Electricity Demand profiles in Mediterranean Small Islands

In communities with a high tourist influx and warm climate, such as Mediterranean small islands, the energy demands for space cooling and domestic hot water are expected to significantly increase during summer. Considering the current energy context, for succeeding energy transition and reducing the dependency on not endogenous fossil fuels, it is paramount to increase the deployment of renewable sources of energy, especially wind and solar which, however, are aleatory and unpredictable. Hence, to reduce the high costs for energy supply in these contexts, the analysis of the variation of energy consumption is fundamental. Moreover, mapping the spatial distribution of energy profiles can be useful to have an overview at a large scale of the considered building stock. Within this frame, a Geographic-Information-System-based procedure was implemented to estimate the residential buildings energy demand profiles, focusing on the seasonal variation. The adopted method can provide a valid supporting tool for decision makers that have to implement smart energy strategies in contexts with a high variation of the energy demand and evident electricity summer peaks. The method for mapping the energy demand profiles, implemented on the small island of Pantelleria, can be applied to other similar contexts, also supporting energy policies in the implementation of renewable energy communities

Energy-environmental assessment of the UIA-OpenAgri case study as urban regeneration project through agriculture.

Sustainable agriculture is strongly promoted by Agenda 2030 and peri-urban agriculture is considered strategic for agri-food sustainability. Although, innovative farming practices are being implemented, the analysis of their impacts often does not reach the required depth. Within the EU project ‘UIA-OpenAgri - New Skills for new Jobs in Peri-urban Agriculture’, a regeneration process of a peri-urban area in Milan (Italy) was started, through the development of an innovative food hub. 28 innovative foodchains are assessed by a Life Cycle Assessment approach based on primary data collected from the involved start-ups. Non-Renewable Cumulative Energy Demand and the Global Warming Potential indicators are assessed and coupled with the productive land indicator. To effectively support involved operators in planning sustainable agriculture practices, the results are presented with GIS maps and insights for improving economic sustainability of involved start-ups are presented. The study shows that the impacts related to the practices implemented (i.e. organic agriculture, including intercropping, agroforestry, ancient grains, etc.) decrease by an average of 55% in energy consumption and 65% on Global Warming Potential if compared to conventional ones. Then, these practices can provide a positive contribution to the Agenda 2030 goal of ensuring sustainable farm production practices