Does anyone know if eQuest can model this system??

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2-Pipe fan coils. Heating source is hot water from boiler. Cooling source is condenser water fro cooling tower. All converted from a water source heat pump.
John R. Aulbach, PE

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Hi John,
There is a chiller with TYPE=WATER-ECONOMIZER but it looks like there has to be another actual chiller attached to the loop for it to work. You could model a very small mechanical chiller along with a water-economizer chiller, with both chillers attached to a condensing loop served by a cooling tower. You will probably get a high number of unmet cooling hours unless the FCUs never see much of a cooling load.


William Bishop, PE, BEMP, BEAP, CEM, LEED AP
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See also:

* There?s a new chiller type ?strainer cycle? which is what it sounds like: Tower water circulated through the building?s airside coils!
* Review the updated reference entries on waterside economizer ? we now have a lot of new flexibility to explicitly model a lot of real-world situations!!!

In my practice with calibrating real-world 2-pipe systems, I have often found it worthwhile to devote extra attentions to interviewing the occupants and facility managers to really lock in on expected/advised thermal comfort behavior. It isn?t uncommon for example to find, such systems in climates with pleasant-enough swing seasons deliberately push off both heating and cooling loops ? you may find some extra flexibility here by leveraging the option to define annual cooling/heating availability schedules at your airside system coils, in conjunction with your loop operation inputs. On the other hand ? occupant behavior during these periods likely will result in some unmet hours if you do nothing else, but be mindful they may not really be uncomfortable and this could represent a miss in your modeled accuracy. Depending on whether the facility was designed thoughtfully with operable windows and cross-venting paths (that haven?t been screwed/boarded shut for noise), you may find that comfort is generally maintained at very low energy draws? whereas in other cases the swing seasons may entail dropping plant energies only to blow up the elec meter with new space heaters/circ fans.


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