Development of concepts for cost-optimal nearly zero-energy buildings for the industrial steel building sector

After 2020, all new buildings in Europe must be built as "nearly zero-energy buildings" (NZEB). For residential and certain commercial building types, significant experience in both research and practice is already available for such ambitious building standards. However, for industrial buildings, such as warehouses and production buildings, NZEB is still a new field. To date findings for residential and office buildings are often used to define standards for the entire building sector. However, industrial buildings have completely different thermal behavior due to their different building shapes, materials, interior temperatures, usage times and internal gains from processes and machines. Therefore, new concepts are required for nearly zero-energy industrial buildings. In this research, such concepts were developed based on large parametric studies simulating more than 1800 different variations in a building simulation model coupled with a 3D transient finite difference ground model and an air-flow network simulation. To gain the required input data for the air infiltration simulation, extensive leakage measurements in a therefore built air-tightness test stand were conducted. According to the EU directive stipulating the NZEB standard, NZEBs have to be cost-optimal. Thus, the focus of this work was on developing cost-optimal solutions to meet the NZEB standard. The results are building concepts for warehouses and production buildings that have 50-75% lower heat energy demand than current (2015) building standards in Germany. These heat energy savings are primarily achieved by increased air tightness, decreased thermal bridges, optimized floor slab insulation and solar optimization. Significantly increased insulation thicknesses are only cost-effective for industrial buildings with low internal gains but relatively high interior temperatures. Previous standards almost exclusively concentrated on increasing the thermal insulation, while the other parameters were often neglected. (C) 2016 Elsevier Ltd. All rights reserved.