ResAdBuildings

Background

South Korea and Germany differ in their climatic conditions and structural building properties. With the focus on residential buildings, both countries have different approaches to assessing and increasing resilience to heavy rain and summer heat and thus adapting to climate change.

Aim

The aim of the project is to identify the differences in climatological boundary conditions (monsoon in South Korea, more intensive heat waves than in Germany) as well as constructional features and based on this to point out corresponding risk potentials with regard to heavy rain and heat events.In addition, it will be demonstrated how the different countries proceed to reduce vulnerability.  Finally, the effectiveness of summer heat adaptation measures will be analysed by means of thermal building simulation of a common Korean and a German multi-family house type.

Analysis approach

Within the project, different climate adaptation measures representative for the climate conditions in Germany were analysed and summarised for the Korea Environment Institute (KEI) in Sejong, South Korea. The focus is set on summer heat, extended to heavy rain and flooding, which are increasing in intensity and duration in both countries, Germany and Korea. In sumemr 2019, a workshop between representatives of the IOER and the KEI took place in Dresden, Germany, where the KEI presented the requirements and the IOER presented the first results. At the end of 2019, the results were summarised in the English-language report entitled "Climate Change Protection and Adaptation in Germany regarding Summer Heat Waves and Heavy Rainfall" and submitted to the KEI. The KEI in turn integrated the results into its report "A study on how to provide land and building information considering climate adaptation" (1).

Results

Within the project, it became clear that the two countries differ in terms of appropriate summer heat adaptation measures:

1. South Korea and Germany differ significantly in climatic conditions despite having the same temperate climate zone. South Korea has longer periods of air temperatures above 30 °C over several weeks and significantly more intensive rainfall as a result of the local monsoon.
2. Performed thermal building simulations showed that due to the high night-time outdoor temperatures in South Korea (mostly above 20 °C), compared to Germany, the possibility of passive night-time cooling via free ventilation is no longer sufficient to ensure a low overheating risk in residential buildings. The resulting summer maximum room temperatures, applying German or South Korean climate conditions to the same building, are shown in the figure below. Due to the clear climatic differences, room cooling in Korea is commonly done using technical possibilities. Accordingly, passive heat protection measures on the building, such as sun protection and the use of thermal storage in Germany, are hardly used in South Korea.
3. The residential building structure in South Korea differs significantly from that in Germany, with much more compact and high-rise buildings in South Korean cities. The building structure also differs. While in Germany, old buildings have solid exterior walls and new buildings usually exhibit exterior insulation, in South Korea the emphasis is on interior insulation of exterior walls up to 12 cm thick. Among other things, this difference has massive effects on the thermal storage capacity of the building. In addition, tenants in South Korea have the option of routing the exhaust air pipes required for the refrigeration units through the outer wall of their flat, which is usually difficult in Germany due to the need for the landlord's approval.
4. The considerably lower electricity prices in South Korea leads to the fact that heating is partly done directly with electricity and that the efficiency of cooling devices and the use of passive cooling measures are hardly in the focus of the residents. Combined with the high share of fossil power generators in South Korea's electricity mix, this causes high greenhouse gas emissions in the residential sector. This is countered by the low living space requirement per resident and the higher proportion of multi-family houses in South Korea compard to Germany.

Accurate component analyses of Korean single- and multi-family houses were conducted, which were transferred to the building performance simulation. The detailed comparison of two reference apartment buildings, a representative 40-story high-rise building from Korea and a 5-story low-rise residential building from Germany, and the different effectiveness of climate adaptation measures to summer heat in Korean and German climate will be published in an English-language journal by mid-2021.