Energy retrofit analysis of cross-laminated timber residential buildings in Seoul, Korea: Insights from a case study of packages

Cross-laminated timber (CLT) is a potential option to achieve reductions in carbon emissions and energy consumption. CLT construction systems are environmentally friendly compared to more energy-intensive materials. In this study, the mid-rise apartments with CLT proposed by ASHRAE 90.1 were analyzed for energy consumption. First, the energy consumption of CLT buildings during heating and cooling was analyzed using four types of insulation. For CLT buildings, the airtightness was approximately 0.61 ac/h, (about 0.2 ac/h lower than that of the steel-frame buildings), suggesting that air-tight performance can reduce energy consumption. Energy-saving technology packages were applied to CLT buildings using rock wool insulation, which showed the highest total energy savings of 82.71 MWh, indicating economically advantageous hybrid-insulation. After the analysis of energy consumption according to the type of insulation, the energy retrofit was applied. Second, five energy-saving packages (including energy-saving, heating and cooling, and renewable energy technologies) were applied to two selected CLT buildings to further study energy consumption and energy efficiency. For CLT building using hybrid insulation, Package 3 reduced the total energy consumption by 14.14%, while for CLT building using rock wool insulation, Package 3 had the highest total energy consumption at 12.81%.