EN 12831-3 : Energy performance of buildings - Method for calculation of the design heat load - Part 3: Domestic hot water systems heat load and characterisation of needs, Module M8-2, M8-3.

This standard describes a calculation method for determining the heating capacity and storage volume required for the sizing of domestic hot water production systems, ranging from direct-heating appliances without storage to systems with low heating capacity and large storage volumes. It covers, for various applications, charged storage systems, characterized by a minimal mixing zone, and mixed storage systems, characterized by a pronounced mixing zone. It also provides standardized methods for determining the energy needs associated with domestic hot water production in residential and non-residential buildings, either for an entire building or for a building zone. Its place within the set of Energy Performance of Buildings (EPB) standards is defined according to the modular structure established by EN ISO 52000-1. The relationships between modules, EPB standards and technical reports are presented in CEN ISO/TR 52000-2; a single module may be covered by several standards, and conversely, a standard may relate to several modules.