[Bldg-sim] NECB Reference Building Fan Power

[Aaron Smith]

Hello,

 

I’m curious about other’s take on Reference Building fan power for projects where the Proposed building has terminal units with a DOAS system.  Let’s say you have fan coil units and a central DOAS system with heat recovery.  In doing the 10kW fan power check, would you include fan power from your DOAS system as well as all the terminal units?  If so, would you only include the fan power for the supply fan in the DOAS system?

 

See some excerpts from the 2015 NECB pasted below.

 

Thanks,
Aaron

 

8.4.4.18.(5) Where the proposed building's secondary system does not meet the requirements of Clause 5.2.3.1.(1)(b), the reference building's secondary system shall be modeled as having an identical fan power demand.

 

5.2.3.1 Application 

1) Except tor equipment covered by Article 5.2.12.1. and whose minimum performance includes fan energy, this Subsection applies to all fan systems 

a) that are used for comfort heating, ventilating or air-conditioning, or any combination thereof, and

b) for which the total of all fan motor nameplate ratings is 10 kW or more (see Note A-5.2.3.1.(2)).

2) For the purposes of this Subsection, the power demand of a fan system shall be the sum of the demand of all tans required to operate at design conditions to supply air to the conditioned space. (See Note A-5.2.3.1.(2).)

 

A-5.2.3.1 .(2) Fan System Design. Although the allowed maximum power demand of a fan system based solely on the supply airflow, the calculation of actual power demand includes supply fans, return fans, relief fans, and fans for series fan-powered boxes, but not parallel-powered boxes or exhaust fans such as bathroom or laboratory exhausts.

 

A-5.2.3.2.(1) Constant-Volume Fan Systems. This type of system includes bypass variable-air-volume systems in which the airflow through the tan is not varied. Both supply and return fans must be accounted for, but not exhaust fans. The power demand of the motors refers to the power drawn by the motors and not their nameplate rating.

 

 

 


     Aaron Smith, P.Eng

    Principal, Mechanical Engineer

 

   LEED® AP BD+C, BEMP, BEAP, CGD

       


     t: (902) 422-7393

     f: (902) 423-4945

     e:  <mailto:asmith at mreng.ca> asmith at mreng.ca

     www.mreng.ca <http://www.mreng.ca/>  

 


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