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Retrofitting energy-inefficient external walls would improve the energy performance of building envelope by utilizing new insulation materials to decrease heat transfer. However, previous researches mainly based on environmental and economic considerations are still partial and could hardly provide a holistic perspective for the optimal selection of external walls retrofit techniques. To address this problem, this paper proposes a novel heterogeneous multi-criteria group decision-making (MCGDM) framework in which the ratings of schemes are described with real numbers and linguistic variables and the weights of criteria are unknown. Firstly, an evaluation index system is established covering criteria of thermal insulation property, technique, durability, and economic efficiency. Secondly, building information modeling (BIM) is utilized to determine multiple retrofit schemes and derive the heat transfer coefficient. Thirdly, after heterogeneous evaluation values are unified, a combined weighting approach is developed based on best worst method (BWM) and the similarity method before fuzzy VlseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR) method is applied to rank the alternatives. Fourthly, the applicability of the proposed framework is demonstrated by a case study of the external wall retrofit scheme selection in Beijing, which reveals that extruded polystyrene (XPS) and expanded polystyrene (EPS) insulation schemes are the compromise choices with aggregating index Q k of 0.0032 and 0.0967 respectively, while rock wool insulation scheme is the last option with Q k of 0.7182. The stability of ranking results is proved with the changing weight of maximum group utility, and the effectiveness of the proposed framework is verified by a comparative analysis. This study can facilitate the implementation of building envelope retrofit by providing useful guidance for selection of external wall retrofit schemes. • A heterogeneous MCGDM framework is proposed to assess retrofit schemes. • BIM is integrated with MCDM method for a comprehensive evaluation. • XPS and EPS schemes are the compromise choices for the case study. • A novel method is proposed to convert two data forms to a unified form. • The extended application of proposed framework facilitates urban green retrofit. [ABSTRACT FROM AUTHOR]

With the concerns of environment protection, electric vehicle (EV) is regarded as a promising transportation tool for green cities project. Since the amount of EV is rising shapely, the EV charging demands is also rapidly generated. However, seeking suitable charging facilities is not easy for EV users, new energy companies run charging station separately for self-interests, and charging pile information is not transparent for drivers. This dilemma is not solved until the merging of blockchain technology. In this paper, a novel EV charging system is proposed for the cooperation of new energy companies and providing convenient charging services for users. In this system, charging information is managed and recorded by the company alliance based on consortium blockchain, which is tamper-resistant and multi-centralized. Meanwhile, a new smart contract is designed to balance the allocation of company' charging users, so that the profits of different new energy companies could be fairer. To equilibrate the interest of companies and EV users, a Bio-Objective Mixed-Integer Programming model (BOMILP) is proposed as the mathematical logic of smart contracts. Furthermore, we proposed a new algorithm named Limited Neighborhood Search with Memory (LNSM) to support the implementation of smart contracts, which could make the smart contract running faster and has a better performance. At last, the proposed EV charging system and the smart contract are validated through a real case study with the EV charging data in Beijing, China. [ABSTRACT FROM AUTHOR]