For this new exhibition and office building in Seoul conceptual approaches employing natural forces, natural heat sinks and sources and natural resources and energy flows for the buildings climate control and lighting were developed to ensure low energy demand in building operation and optimal internal environmental conditions in the spaces. The concepts developed encompass the use of high performance building envelopes, low-energy air/ water climate control systems including demand controlled ventilation and highly effective sensible and latent energy recovery, mixed-mode ventilation and lighting control systems with daylight and presence detection. The “vertical green” spaces provide daylight and act as thermal buffer zones. Low energy large surface area radiant heating and cooling systems are used to cool the exhibition spaces in summer and heat in winter, offering advantages both in terms of comfort (low air velocity in the occupied zone) and energy (low water temperatures for heating and high water temperatures for cooling allow the use of high-entropy energy sources). The approach is particularly effective, as during hot weather the solar radiation falling on the floor through the large areas of glazing can be directly removed by the system before becoming a load on the space. Extensive computer simulations were carried out to support the optimization of the design.