Dynamic evaluation of the cooling capacity of Thermo-active building systems

This paper offers a guide for the design of water-based embedded heating/cooling systems to promote the use of renewable energy sources and provide a method for actively integrating the building mass to reduce peak loads, transfer heating/cooling loads to off-peak times, and decrease system size. Peak loads can be reduced by activating the building mass using pipes embedded in the main concrete structure of the building-a thermo-active building system (TABS). For these types of systems, the steady-state calculation of heating and cooling capacity is not sufficient to evaluate the cooling capacity in practice. The dynamic behavior can be evaluated by full dynamic computer simulations of buildings with systems. This is, however, often regarded as too complicated and takes too much time in the design phase. Therefore, this paper presents a simplified method that is being implemented as a European standard. The proposed methods are used to calculate and verify that the cooling capacity of the system on the room side is sufficient to keep the room temperature under a given criterion. The method also calculates the cooling requirement on the water side, which is needed for sizing cooling systems, including the chiller

Building design in a changing climate – Future Swiss reference years for building simulations

With global climate change, temperatures in Switzerland are projected to rise in the coming decades, according to the national climate scenarios CH2018. Associated with the mean temperature increase, heatwaves are expected to become longer, more frequent, and more intense. The changing climate will affect the indoor climate as well as heating and cooling needs. In building design, these climatic changes have to be planned for today in order to ensure a comfortable indoor climate in the future.In collaboration with practitioners, a reference climate data set for the future is created that specifically targets building designers and engineers. The data set consists of hourly weather data of one-year length based on the Swiss climate change scenarios CH2018. These future reference years are representative of two time periods in the future: one around 2030 and one around 2060. Climate change uncertainty is considered by using two emission scenarios (RCP2.6 and RCP8.5). Reference data for the future is provided not only for a typical year (called Design Reference Year, or DRY) but also for an above-average warm summer. The data is available at the sites of 45 measurement stations across Switzerland, including four stations inside major cities to take the urban heat island effect into account.The generated climate data set is applied to a building model to provide an application example. The results point out that the cooling needs will substantially increase, which is why an adaptation of the building design to the changing climate is vital