Demonstration of the Nearly Zero Energy Building Concept

Nearly zero energy buildings (nZEB) will become an obligatory energy efficiency standard in Europe. Following to common guidelines in European legislation, the countries investigated technical and economic framework for the preparation of detailed national technical definition of nZEB. Slovenia accepted the nZEB criteria in early 2015. This paper describes the technical and economic background for identification of economically viable concepts of highly energy efficient apartment building. The highrise demonstration building Eco Silver House revealed that meeting nZEB standards was not an easy task, not so much for technical reasons, but mostly due to the processes, inadequate skills, not fully compliant regulation and insufficient possibilities for interaction between the building and energy networks. Analysis of cost effectiveness showed that the Eco Silver House fulfilled minimal requirements of cost-optimal for apartment building with Net Present Value of 272 EUR/m2 and Primary energy use of 79 kWh/ m2?a in line with the Slovenian national cost optimal study of minimum energy performance requirements from the year 2014. At the time, the requirement of 50% share of renewables in final energy use is not fulfilled, but will be easily reached when EU2020 energy efficiency targets set in the Slovenian Energy Act regarding the RES share in district heating systems and public power grid will be gradually implemented. The demonstration project FP7 EE-HIGHRISE confirms that in spite of the barriers, the nZEB minimum requirements defined on profound theoretical studies can be met in practice.

Review on the recent progress of nearly zero energy building frontiers in China

Energy efficiency improvement in Chinese construction has progressed rapidly over the past two decades.Nearly zero energy buildings(NZEBs),as an integrated solution for energy-efficient construction,have gained significant attention during China's 13th Five-Year Plan period,with continuous maturation of the technical system.In this study,a research framework built upon the accomplishments of China's National Key Research and Development Program is developed,and an in-depth analysis of the most cutting-edge research is provided by thoroughly reviewing the work conducted earlier.Developing NZEB in China has been categorized into three stages based on the characteristics of technological development:(1)definition and standards,(2)demonstration and promotion,and(3)cross-domain integration.This study discerns four noteworthy development trends by examining comprehensive data spanning the last decade from 100 NZEB and zero energy building.Further,a comprehensive analysis of essential technology advancements in line with these identified trends is performed.The issues and challenges arising from the increased application of renewable energy in the context of China's carbon peak and carbon neutrality goals have also been discussed.Finally,based on this analysis,the challenges and corresponding suggestions for future research directions were proposed to help guide future studies exploring emerging trends in the NZEB field.

Indoor environment of nearly zero energy residential buildings with conventional air conditioning in hot-summer and cold-winter zone

According to the few researches on Nearly zero energy residential buildings(NZERB)in hot-summer and cold-winter zone,although it could reduce the cooling load of buildings due to its high thermal insulation and air tightness,it still needed for certain cooling in summer.This paper studied indoor environment of NZERB un-der three kinds of air-conditioners(split-type air-conditioner,multi-line air-conditioner and ceiling radiant air-conditioner).Firstly,a simulation model of NZERB was established based on Nanjing,a typical city in hot-summer and cold-winter zone.Secondly,variation of indoor air temperature and building load characteristics with outdoor air temperature were studied.Thirdly,indoor environment and energy consumption under three selected con-ventional air-conditioners in summer were simulated.Finally,the discussion was given,and an air-conditioner combining with convective and radiant cooling were proposed.The results indicated that the air-conditioner needed to be turned on in NZERB in hot-summer and cold-winter zone due to the room air temperature in off-air condition ranged from 32℃to 36℃,which was higher than designed indoor environment temperature in sum-mer,but the indoor environment of NZERB under three selected conventional air-conditioners could not meet the requirements of energy saving and comfort at the same time,and a proposed convective-radiant air-conditioner could be fast,stable,and energy saving.The findings can provide a reference for conducting active technology in NZERB.