Abstract
In a general building retrofit process, the reinforcement of insulation performance or air-tightness in walls and windows are conducted to reduce the maximum cooling and heating load of buildings. A heat source consists of heat-source equipment and water-pipe systems, which are replaced with high-efficient specification materials. Most of them are simply replaced with the same capacity as the previous heating equipment. This study aims to investigate matters required for decision making in a retrofit plan, such as conducting an investigation of the maximum load reduction in buildings obtained by the retrofit and the capacity of heat-source equipment that reflects the reduction, and the re-use or replacement of the water-pipe system, etc. in advance. This study verified that when the capacity of heat-source equipment was reduced, the pipe diameter of the water-pipe system was also decreased, but if existing pipes were re-used, the transportation power of the pump was reduced due to the reduction in flow velocity. The changes in maximum cooling and heating load through retrofit were quantitatively verified compared to that of the initial design of the building based on previous study results, and flow rates of cool and hot water were determined by re-calculating the capacity of the heat-source equipment. Using the results, the water-pipe system was re-designed, and the annual transportation power of the pump was calculated through simulations. The calculation results verified that the transportation power decreased by up to approximately 10% when oversized pipes were re-used from the existing water-pipe system. Additionally, when the capacity of the heat-source equipment was decreased, reasonable measures considering remodeling, construction duration, and cost were derived.
Highlights
About 36% of global energy consumption is attributed to residential and commercial buildings (41%in Europe, 34% in the USA, 34% in Japan, and 24% in Korea) [1]
The present study aims to consider the changes that maximum cooling and heating loads induced through the replacement of windows and reinforcement of insulation performance in loads induced through the replacement of windows and reinforcement of insulation performance in deteriorating buildings, for large office buildings in Korea, and to search for a retrofit deteriorating buildings, for large office buildings in Korea, and to search for a retrofit method that minimizes the replacement of heat-source equipment
The capacity of heat-source equipment at the time of retrofit was calculated based on the loads obtained in previous studies, and review cases including the range of the water-pipe system were selected
Summary
About 36% of global energy consumption is attributed to residential and commercial buildings (41%in Europe, 34% in the USA, 34% in Japan, and 24% in Korea) [1]. About 36% of global energy consumption is attributed to residential and commercial buildings Steady research and development of methodologies to reduce energy consumption in buildings have been conducted. South Korea has strengthened insulation standards for new buildings to meet a passive house level, which has been used in Germany since 2017, and has encouraged low-consumption energy buildings by using policies such as green building certification and energy efficiency ratings, etc. The retrofit ratio of the buildings in Energies 2019, 12, 4309; doi:10.3390/en12224309 www.mdpi.com/journal/energies. Energies 2018, 11, x FOR PEER REVIEW the permit area from 2002 to 2012 amounted to about 20% [4], among which green remodeling was green remodeling was mostly in buildings [5]. The survey result concentrated mostly in concentrated residential buildings [5].residential
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