BREEAM energy demand definition

asked 2020-02-06 02:41:55 -0600

Tophsla's avatar

updated 2020-02-07 06:21:39 -0600

I have a question for the notion of energy demand. To determine the number of points on the criterion ENE 01, you need to get 3 parameters (for each building model: actual, notion and best practice).

  • building energy demand (MJ/m²)
  • building primary energy consumption(kWh/m²)
  • building emission rate (kgCO₂/m²)

Energy demand definition according to BREEAM International New construction technical manual: The building energy provided for end uses in the building such as space heating, hot water, space cooling, lighting, fan power and pump power. Energy demands are the same as room loads. One of the outputs from the Building Regulations Output Document is for heating and cooling energy demand only, not for any other building energy uses. Heating and cooling energy demands are influenced by factors including building fabric heat loss, air permeability, glazing and shading. If it is the same as the room loads (ie heat gains), it should be measured in W, not in MJ/m2, because J = W/s. As I understand Energy demand is measured in kilowatts (kW) and represents the rate at which energy is consumed. Energy consumption, on the other hand, is measured in kilowatt-hours (kWh) and represents the amount of energy that has been consumed over a certain time period. As a result, I'm a little confused. Can anyone comment on and share their experiences on energy demand from the Breeam perspective?

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Seems like it's a weird use of the term demand... They seem to mean site energy consumption.

Julien Marrec's avatar Julien Marrec  ( 2020-02-06 08:25:40 -0600 )edit

Thank you for your comment. But why they use different word for this? If it's consumption and not demand. So, are you suggest to use just heating and cooling consumption data for this "demand"?

Tophsla's avatar Tophsla  ( 2020-02-06 14:15:05 -0600 )edit

that's how I understand the PDF I linked to yes. Their spreadsheet calculator might be helpful to decide for sure though. I don't do BREEAM modelling so I won't bother, but you should.

Julien Marrec's avatar Julien Marrec  ( 2020-02-07 02:21:11 -0600 )edit