[Equest-users] Fan Cycling Indication in Detailed Report?

[Michael Mantai]

I tried this but it had no effect.  My annual kWh equals my total fan power
times 8760, so I¹m certain that the fans are on continuously.  There must be
something that is keeping them on, but I cannot find it.


On 2/1/12 1:52 PM, "Robby Oylear" <robbyoylear at gmail.com> wrote:

> Michael,
> 
> On a recent project I modeled this same situation.  The way I was able to
> force the system to only operate during a call for cooling or heating was by
> defining a fan schedule with all hours set to 0.  Per the DOE2.2 help
> documentation on fan schedules:
> -   If the value is 0, the fans are off but may be turned on by
> NIGHT-CYCLE-CTRL if zone temperatures warrant it. 
> 
> Make sure to allow night cycle control (cycle on any).  This basically defines
> all hours of the day to be "night" and the fan will cycle on to meet the load
> in the space.  
> 
> Robby Oylear, LEED AP
> Mechanical Project Engineer
> Senior Energy Analyst
>  
> D 206-788-4571
> www.rushingco.com <http://www.rushingco.com/>
> 
> On Wed, Feb 1, 2012 at 10:00 AM, Chris Hadlock <cjhadlock at gmail.com> wrote:
>> Hi Michael,
>> 
>> I would just run an hourly report for one of your heat pump systems and pick
>> up hourly flow rate and fan energy. This way you can see how often your fans
>> are running and whether they are cycling or running continuously. With heat
>> pump systems, there are key words under the Fans tab (for a given system)
>> that will indicate the control on the fans. One is night cycle control and
>> the other is indoor fan mode (within the Flow Parameters tab). If your fans
>> are not cycling, it is likely due to those two key words (or the fan schedule
>> you have specified).
>> 
>> Chris
>> 
>> 
>> On Wed, Feb 1, 2012 at 12:44 PM, Michael Mantai <mmantai at systemworcx.com>
>> wrote:
>>> I'm modeling a 6-story hotel.  Baseline is PTAC.  I set up the baseline to
>>> have outside air at each PTAC with the fans running continuously.  The
>>> Proposed Case is watersource heat pumps.  Outside air is through dedicated
>>> units at the corridors.  I've set (at least I am trying to set) the heat
>>> pump fans to cycle on the thermostat.  I've set the heat pumps to 0 CFM
>>> outside air.  When I run the two models, the ventilation fan energy is
>>> nearly identical.  I expected to see some fan energy savings with the heat
>>> pump fans cycling.  When I look at the detailed output report, the SS-C for
>>> the heat pumps seems like it is showing fans running continuously.  I say
>>> this because the "hours floating" are less than the "hours fans on", and the
>>> "hours fans cycle on" is zero.  This implies to me that the fans are running
>>> continuously.  However, when I look at the reports that show fan energy
>>> consumption, the months with floating hours show significantly reduced fan
>>> energy, which to me implies that they are cycling.  The total fan kW in the
>>> proposed model is about twice that of the baseline, so from that standpoint
>>> maybe the kWh being about the same is correct.  I set up the PTAC units at
>>> .3 watts/CFM per ASHRAE.  I set up the heat pumps fans with a static
>>> pressure input from the design drawings rather than input the fan motor
>>> sizes (used .2" w.g. Static).
>>> 
>>> Also, my space cooling energy is higher in the proposed case than the
>>> baseline, even though the envelope is better, the watersource heat pumps
>>> have a lower EIR and the design lighting power density is 30% lower.  I
>>> haven't dug into that yet because I'm still trying to verify my fan cycling
>>> is working.
>>> 
>>> My questions are, can anyone explain how to interpret the SS-C reports in
>>> terms of fan cycling, or point me to which report I should look to really
>>> verify the fans are cycling?  And anyone modeled a similar comparison, and
>>> if so, what type of results did you get with respect to cooling energy and
>>> fan power consumption?  Seems like I should be seeing savings.
>>> 
>>> 
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>> 
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> 

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