adverse effect, heat transmission, concrete core activation, heat pump, thermal storage capacity
During the last years thermal insulation of commercial buildings has been improved resulting in a decreasing demand for heat energy. However, due to lower heat transmission through the facade in office and administration buildings, adverse effects can arise in summer. Through the better insulated facade, the nocturnal heat loss is strongly reduced. Together with the internal heat loads and the increased comfort requirements of the users a cooling demand in winter and during the transitional period is required. Therefore, more energy efficient buildings that have relatively low energy requirements for heating and cooling are in demand today. The heating and cooling of office and administrative buildings with environmental energies from soil, groundwater and outside air are energetically and economically very interesting. Conventional air conditioning systems generally require low system temperatures and are suitable only for limited use of environmental energy. To counteract this effect the thermal concrete core activation is particularly efficient. Water-carrying pipe systems for year-round temperature control of buildings are installed in the solid components with high heat storage capacity. If these pipes are directly supplied with cold from the ground or from a cooling tower in the surrounding air, only the energy to transport the cold water to the user is needed. The heat requirements in winter can also be covered in part with environmental energy by heat pumps. With the use of cooling towers the supply (low outside air temperatures during the night) and the demand of the building (cooling during the day) has a temporal shift. Therefore, the thermal storage capacity of the solid components is important for the temporal displacement of energy peaks. The large heat transfer surfaces allow for a significant heat and cooling capacity already at temperatures with small under- and overheat. Heat supply and heat discharge are under constant change throughout the year. This paper provides a guideline for planning and execution of concrete core activation systems.