ISO 11855-4:2012允许根据热增益计算热活性建筑系统（TABS）的峰值制冷能力，例如太阳能增益，内部热量增加和通风，以及计算水中的冷却功率需求侧面，用于冷却系统的尺寸，关于冷却器尺寸，流体流量等 ISO 11855-4:2012定义了一种旨在计算非稳态条件下的加热和制冷能力的详细方法

ISO 11855-4:2012 allows the calculation of peak cooling capacity of Thermo Active Building Systems (TABS), based on heat gains, such as solar gains, internal heat gains, and ventilation, and the calculation of the cooling power demand on the water side, to be used to size the cooling system, as regards the chiller size, fluid flow rate, etc. ISO 11855-4:2012 defines a detailed method aimed at the calculation of heating and cooling capacity in non-steady state conditions.