Requirements for new Non-residential Buildings
Besides the general requirements for new buildings, for non-residential buildings the following requirements apply:
• limitation of the yearly primary energy demand by a maximum value determined individually ("overall energy performance")
• limitation of the average heat transmission coefficient for several groups of components of building shell ("requirement on thermal insulation")
• limitation of either solar irradiation indicators or overtemperature degree hours according to DIN 4108-2 ("summer heat protection")
For all three requirements, the way to proof as well as the boundary conditions are fixed via reference to certain technical regulations in order to ensure that the requirements are clear without ambiguity.
Reference Building Approach
The requirements pay respect to the individual building task. The size of the building, its shape and orientation (often determined by the building site) as well as the relative share of the shell components may limit the possibility to reduce the primary energy demand and the transmission heat loss. That’s why the maximum values in Germany are determined using the reference building approach.
Concerning its overall geometry, its orientation and its use pattern the reference building is identical to the real building. The reference building’s energetic features of the shell (outer walls, roof, windows, doors, ground plate, thermal bridges, tightness) as well as the features of the building services (heating-, domestic hot water- and AC-/ventilation systems), however, are pre-determined for the purpose of calculating the maximum values.
The principle of the reference building approach is illustrated on the site "Requirements for new Residential Buildings". For non-residential buildings however, in addition to the features shown there, additional features are added (lighting, differentiated ventilation systems, chillers, building automation, curtain walls), whilst the principle is the same.
For proof of compliance, the same calculation method and identical boundary conditions have to be applied on both versions of the building (reference- and real building). Modern software-solutions calculate the reference building simultaneously; in case that the planer changes e. g. the geometry of the real building, the reference building will be adapted automatically.
According to the current state of legislation (in force since 1st January 2016), the determination of reference building for the determination of the maximum primary energy demand includes an additional reduction factor (0,75), by which the result of calculation using the reference features (basically in force since 2009) has to be reduced for new buildings. This is not applicable for certain zones with internal height exceeding 4 m.
Proof of compliance: primary energy demand
For non-residential buildings, two alternative methods are allowed for proof of compliance:
- DIN V 18599: 2011-12 with zoning foreseen in this standard (according to use pattern of the single zone)
- DIN V 18599: 2011-12 in connection with simplified method (single-zone approach) according to Annex 2 number 3 EnEV with restrictions given there. This approach is applicable exclusively for certain building uses (office-buildings, wholesale- and retail-buildings, trade-buildings, schools and kindergartens, gyms, simple hotels, libraries) with specific limitations. In course of this approach, a certain use pattern is assigned to the building as a whole.
Proof of compliance: requirement on thermal insulation
Irrespective of the chosen approach to prove sufficient limitation of the primary energy demand, the limitation of the average heat transmission coefficients has to be proven for the different groups of shell components according to Annex 2 number 2.3 EnEV.
Proof of compliance: summer heat protection
Irrespective of the above mentioned calculation methods, the proof of sufficient summer heat protection is due to be done according to DIN 4108-2: 2013-02. The maximum values are also part of this standard. In addition, the standard sets up some conditions that allow skipping the calculation.