[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [EnergyPlus_Support] Total heating load boiler 60 % higher than total heating load rooms





One thing to watch out for is that boiler curves are not setup normilzed to outlet (or inlet) temperature which means they are temperature dependant. The default curves in DB are for boilers with a nominal temperature supply of about 70 deg C (with the lower limit at 35C). So your efficiencies may be other than you expect, if you are using other supply water temps.

Mit freundlichen GrüÃ?en- Sent from my iPhone (excuse the brevity)

i. A.
Jean Marais
b.i.g. bechtold
Tel.   +49 30 6706662-23

On 20.04.2015, at 08:20, "geert.bellens@xxxxxxxxxxxxxxxxxxxxxx [EnergyPlus_Support]" <EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:

 

I've done a designbuilder simulation of an office building with fan coil units heating and cooling every room.


In Designbuilder you quickly get the total system heating load (the sum of all rooms) and the Boiler total capacity for heating.

I work with efficiency 100% for the boiler, so normally the heating load of all the rooms, must be the total capacity for the boiler.


In this model, the boiler needs 60 % more capacity ( at 7 AM on the coldest morning in the year) then the sum of the heating load of all the rooms. Later the day, the two are loads are almost equally, so it's just at startup in the morning.


According to the DB support this could be the difference between the inertia of water (fan coils) and gas (boiler).


I've never had such a difference. Is this normal?


What will I communicate to the client as Heating capacity for the boiler? The sum of all the rooms ? Or the boiler capacity as calculated ? (which is a lot higher than the sum of all the rooms)



Geert




__._,_.___

Posted by: "jeannieboef@xxxxxxxxx" <jeannieboef@xxxxxxxxx>


Primary EnergyPlus support is found at:
http://energyplus.helpserve.com or send a message to energyplus-support@xxxxxxxx

The primary EnergyPlus web site is found at:
http://www.energyplus.gov

The group web site is:
http://groups.yahoo.com/group/EnergyPlus_Support/

Attachments are currently allowed but be mindful that not everyone has a high speed connection.  Limit attachments to small files.

EnergyPlus Documentation is searchable.  Open EPlusMainMenu.pdf under the Documentation link and press the "search" button.





__,_._,___