Search Results (5)

The optimization of the energy system serving users’ aggregations at urban level, such as Energy Communities, is commonly addressed by optimizing separately the set of energy conversion and storage systems from the scheduling of energy demand. Conversely, this paper proposes an integrated approach to include the demand side in the design and operation optimization of the energy system of an Energy Community. The goal is to evaluate the economic, energetic, and environmental benefits when users with different demands are aggregated, and different degrees of flexibility of their electricity demand are considered. The optimization is based on a Mixed-Integer Linear Programming approach and is solved multiple times by varying (i) the share of each type of user (residential, commercial, and office), (ii) the allowed variation of the hourly electricity demand, and (iii) the maximum permitted CO₂ emissions. Results show that an hourly flexibility of up to 50% in electricity demand reduces the overall system cost and the amount of energy withdrawn from the grid by up to 25% and 31%, respectively, compared to a non-flexible system. Moreover, the aggregation of users whose demands match well with electricity generation from renewable sources can reduce CO₂ emissions by up to 30%. Full article

Reducing carbon emissions associated with buildings is a top priority for mitigating the human impacts from climate change. Reducing carbon emissions resulting from the manufacturing, designing, constructing, investing, owning, operating, occupying, renovating, and demolishing of buildings is essential to safeguard the environment from negative consequences. This paper relates to the environment and human influence on the climate and addresses the different amounts of embedded carbon for building activities ranging from new buildings to major renovations to minor renovations, using a methodology termed the “whole-life carbon measurement”. The data from the case studies indicate that refurbished or renovated buildings exhibit the least carbon footprint compared to other alternatives. This outcome can be attributed to the sustainable practice of reusing materials, coupled with the positive effects of retrofitting. The expectation that refurbished buildings would demonstrate a lower carbon footprint aligns with the principles of sustainability, emphasizing the environmental benefits of repurposing existing structures. While embedded carbon is currently not priced, it is important that it be accurately measured over the entire life cycle of buildings if the real estate industry is to meet sustainability goals. Full article

Against the backdrop of rapid urbanization, with the expansion of administrative boundaries, some former villages have been transformed from administrative to urban in the sense that they have become special “village-to-city areas”; in this context, the housing pattern, which was previously dominated by self-built houses, is facing many challenges. In particular, the frequent occurrence of safety accidents in self-built houses in the village conversion areas in recent years constitutes an important component of urban spatial vulnerability. However, the ensuing “one-size-fits-all” ban on self-built housing has also raised concerns among scholars. In order to better guide the planning and construction of self-built houses, official safety inspections, planning guidance, and institutional constraints are essential. However, the safety inspection of self-built houses across China is difficult. On the one hand, it is challenging to obtain data on individual buildings (e.g., age, use, building structure ratio, foundation, structural condition, illegal demolition and alteration, and illegal use), and the methods of obtaining such data rely mainly on the basic checking of the safety grids under the responsibility of grassroots safety officers. However, the current organizational system of safety officers is not perfect, and the relevant evaluation training also has limitations. On the other hand, due to the city’s finances, development stage, and other reasons, the agricultural-to-residential areas in the cities of poverty-stricken counties are not likely to be renewed as rapidly as the cities of developed regions but instead may face long-term renewal timelines. Therefore, for the agricultural resettlement areas in the cities of poverty-stricken counties, it is necessary to screen the current problems, systematically study the mechanism and strategy of their renewal based on the management framework of the whole process, and carry out the organic renewal of self-built houses, so as to gradually realize a safe and resilient development mode. This paper establishes a framework for the renewal of self-built houses oriented to security resilience based on the theory of fortress land under the urban form theory of Conzen. Taking Lianhua County as a case study, we analyze the problems and issues related to self-built housing areas through an investigation of the current situation. Then, in response to the existing problems, based on the comprehensive investigation of the safety of self-built houses, we clarify the planning objectives and value orientation and suggest (i) the adoption of hierarchical and classified planning and construction control for the self-built housing areas of villages converted to residences in accordance with the local conditions; (ii) the enhancement of government supervision in the use of self-built houses and the establishment of laws and regulations; and (iii) renewal planning in an orderly manner to enhance the safety resilience of the self-built housing areas. Based on the renewal study of self-built houses in Lianhua County, a systematic exploration of the planning, construction, and governance strategies of self-built houses in China is carried out, which can provide a reference for the decision making of relevant departments. Full article

South Korea has industrialized and urbanized rapidly since the 1970s, and subsequently, the historic downtown areas of major cities have been hollowed out as the population and industry have become concentrated in urban centers. Based on the Urban Decline Indicators of Korea, in accordance with the Urban Revitalization Act of the South Korean government, a comparative analysis of the population changes, office vacancy rate, building aging rate, decrease in the number of industries and employees, and housing supply and demand in historic downtown areas and new urban areas of six major South Korean cities demonstrated that all six historic downtown areas have declined significantly. Currently, little research is available in South Korea on the expansion of urban living and the inflow of urban residents through office-to-residential building conversion. Therefore, this study explores the expansion of urban residences to revitalize these historic downtown areas. To this end, this study examines the feasibility of converting poorly functioning, vacant offices in historic downtown areas into residential spaces to present a sustainable strategy for their complexation. This study finds that office-to-residential building conversion is a sustainable way to recover urban space and grow the population and industry in historic downtown areas. Full article

Solar air collectors have various applications: on the one hand, they can be used for air heating in cold seasons; on the other hand they can be used in summer to evacuate the warm and polluted air from residential, offices, industrial, and commercial buildings. The paper presents experimental results of a solar collector air, under the climatic conditions of the Southeastern Europe. The relationships between the direct solar irradiation, the resulting heat flow, the air velocity at the outlet, the air flow rate, the nominal regime of the collector and the efficiency of conversion of solar energy into thermal energy are all highlighted. Thus, it was shown that after a maximum 50 min, solar air collectors, with baffles and double air passage can reach over 50% efficiency for solar irradiation of 900–1000 W/m². The article also presents a mathematical model and the results of a computational program that allows sizing solar collectors for the transfer of air, with the purpose of improving the natural ventilation of buildings. The article is completed with case studies, sizing the area to be covered with solar collectors, to ensure ventilation of a house with two floors or for an office building. In addition, the ACH (air change per hour) coefficient was calculated and compared. Full article