Energy needs and energy uses

miguelnery · Posts: 72

In one of the new european standards (prENwi14), they ask to report, separately, energy needs and energy uses.
Can you tell me how to obtain this data in DB?

Best regards,

Miguel

Andy Tindale · Posts: 1148 Location: Stroud

Miguel,

Energy use data is accessed at the building level by selecting Fuel breakdown as the data. This shows fuel consumption data broken down by end use, typically:

Heating
DHW
Fans
Pumps and other miscellaneous equipment
Room equipment (electric)

From our previous correspondence I think you need room equipment energy consumption to be broken down more finely into various categories.

We plan to implement this as soon as possible.

Regards
Andy

miguelnery · Posts: 72

Hy Andy,

My doubt it’s how to get the energy needs.

By prENwi14 definitions:

Energy need for heating and cooling is the heat to be delivered, or to be extracted, by the system to maintain the set point temperature.
And
Energy use for space heating and cooling is the thermal energy to be delivered to the system to satisfy the energy need

From what I understood, the energy needs for heating and cooling are calculated on the basis of the heat balance of the building.
The heat balance being the sum of:
Heat transfer by transmission, ventilation, internal heat sources.

My questions are:
1 - How can I calculate the energy needs in DB?

2 - Making the addition of internal gains and fabric and ventilation?

From our previous correspondence you told me that General Lighting Gains and Computer +Equip Gains where energy uses and not thermal gains to the building.

3 - This is right? Is it also true for Process Gains and Catering Gains?

If so,
Just Occupancy Gains, Transmitted Solar Gains and Heating and Cooling Delivered could be inputed as gains.

4 - Where can I get internal gains from General Lighting Gains, Computer +Equip Gains, Process Gains and Catering Gains?

Best regards,

Miguel

Andy Tindale · Posts: 1148 Location: Stroud

Hi Miguel,

We are having problems understanding each other because we are using different terminology!

1. From what you say, your term 'energy needs' seems to correspond to the term 'heating/cooling loads' which I believe is the term most commonly used in the UK and US. This is the heat/cooling energy which when supplied to a zone causes the heating/cooling temperatures set point to the met. In DesignBuilder terminology the heating and cooling loads are:

'Heating delivered' and
'Cooling delivered'

This data is available at zone level and totals for the building can also be seen at building level.

These are not to be confused with boiler and chiller fuel consumption which is the actual total fuel energy consumed at the plant. This data is accessed at the building level only in DesignBuilder.

General Lighting, Computer + Equip, Process, Catering and other gains reported in DesignBuilder are all internal heat gains to the space and do not correspond directly to fuel consumption. This data can be added to the fabric heat loss/gains and to the heating and cooling delivered data to give heat balances.

I apologise for the confusion and hope that this clarifies things!

Regards,
Andy

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