Tips & Tricks: Adjusting Sefaira Architecture plugin settings for projects in Denmark

While the space use internal condition assumptions are fixed in the Architecture plugin, we can still use some of the property sliders to simulate different internal condition settings before uploading the project into the web app. The following example is for Denmark, where BR10 / BR15 prescribe certain underlying assumptions which are quite different from the standard Sefaira space use settings.

Note: The following methodology applies to EnergyPlus mode only.

 

Recommended settings

In short, the recommended settings (EnergyPlus mode)for non-residential projects in Denmark are:

Ventilation rate = 3 L/s.person

Equipment = 0 W/m2

Lighting = 7.5 W/m2

 

Note: the remaining recommended settings for Denmark are provided by the BR10/15 baseline settings article.

 

Explanation for the recommended settings

Below is a summary of the comparison between Sefaira default assumptions and BR10/BR15 prescribed values. Some of these values are fixed assumptions in the Sefaira plugin, others are adjustable. The sections below will explain how we can leverage the variable settings to compensate for differences in fixed assumptions.

 

 

Sefaira default – Office profile

Denmark BR10 – Non-residential profile

Occupant density

10 m2/person (fixed setting)

25 m2/person

Equivalent occupied hours

2370 hrs (fixed setting)

1710 hrs

Ventilation rate

15 L/s.person (variable setting)

0.3 L/s.m2

Equipment load

25 W/m2 (variable setting)

6 W/m2 (not part of EUI)

 

Ventilation rate:

The minimum ventilation rate in BR10 regulations is specified as 0.3L/s.m2, which is equal to 7.5L/s.person when accounting for the occupant density of 25m2/person.

In the Sefaira Architecture plugin we specify the ventilation rate per person. If we want to achieve the same minimum ventilation rate as prescribed by BR10, we therefore need to factor in that we are assuming an occupant density of 10m2/person. To simulate a rate of 0.3L/s.m2, the per person rate therefore needs to be:

Ventilation = 10m2/person x 0.3L/s.m2 = 3L/s.person

 

Thermal gains from occupants:

The assumed thermal gain from occupants is 100W per person. Equipment and lighting thermal gains are assumed to be equal to their power rating. Therefore we can offset any difference in thermal gains from occupants by varying the power ratings of equipment or lighting.

Thermal gain for 10 m2/person = 100W / 10m2 = 10W/m2

Thermal gain for 25 m2/person = 100W / 25m2 = 4W/m2

The difference we need to compensate for in this case is 6W/m2. For BR10/15 regulations, we are considering thermal gains from equipment (at a prescribed 6W/m2) but we are excluding the direct energy demand from the target EUI figure. [Ref: Danish Building Research Institute, SBi 2013:25] Therefore:

 

Compensation in equipment power rating

We can compensate the reduced internal gain by subtracting 6W/m2 from the equipment power rating. As this is only 6W/m2, we are effectively left with no direct energy consumption for equipment, but the thermal gains still correctly accounted for in the higher occupant thermal gains. A positive side effect of this is that no equipment energy is included in the EUI figure, which is in line with what is prescribed by the Danish Green Building Council for standard energy calculations. Therefore:

Equipment = 6W/m2 - 6W/m2 = 0W/m2

 

Adjustment in lighting power rating

There is no minimum power rating prescribed in the Danish building regulations, so we can assume a standard value of 10W/m2 – although modern LED technology could be significantly less than this. To take into account the fact that many modern lighting systems are likely to have a power rating of less than 10W/m2, we can reduce lighting power density to around 7.5W/m2. This should provide energy estimates which are in line with assessment tools such as BR10/BR15 validation software.

Lighting = 7.5W/m2

 

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