Cogeneration with thermal tracking

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Hi eQuest users,

Has anyone successfully modeled a cogeneration system in eQuest with a control system preventing the generators from turning on until a certain minimum heating load threshold is reached?

This is my first time using the generators in eQuest. I am trying to follow "Example 4. Thermal Tracking with Surplus Sale" in the DOE-2 user's manual (available by going to Help, DOE-2 Help, and searching for "Example 4" in eQuest). When I get to the setup for the EQUIP-CTRL, the example indicates that generators can be selected along with boilers when the EQUIP-CTRL is of TYPE = HEATING with the HW loop selected as CIRCULATION-LOOP. However, only my boilers show up as options in the pull-down menu in the tab "Load Range 1" under "Boiler Name." The generators do not appear as options here unless TYPE = ELECTRICAL is selected. This is not desired because I wish to control the generator operation based on a minimum heating load, not a minimum electrical load. I am able to set up the rest of the components in Example 4.

I tried editing the input file to manually add the generators to the control system; I was able to run eQuest with this code:

"Generator Control" = EQUIP-CTRL
LOADS-THRU-1 = 3.75
LOADS-THRU-2 = 100
BOILERS-1 = ( "Boiler 1", "Boiler 2" )
GENERATORS-2 = ( "Elec Gen 1", "Elec Gen 2" )

After doing more experiments, however, it looks like there might be some additional bugs with the control system algorithm. For example, if I put in a generator capacity of 1000kW, hourly outputs show that slightly less than 100kW is generated. If I change the capacity to 10,000 kW, slightly less than 1,000 is generated. Additionally, the generator doesn?t seem to respond to the ?LOADS-THRU? keyword; it comes on even if the LOADS-THRU-1 value is never reached.

In addition to these issues I?m not sure if I correctly understand how to use the GENERATOR-SEQ keywords used in Example 4; I couldn?t find a good explanation in the help file. No luck with these issues on the BLDG-SIM list either.

If anyone has any tips or knowledge that these options in eQuest are not currently operational, I would be happy to hear from you.

Thank you,


Roselin Osser, PE, BEMP, LEED AP BD+C

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Joined: 2012-07-05
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I am having the same problem. When using "track thermal load" and rejecting heat to a space heating loop, very little or no heat is recovered. However, rejecting heat to a process loop with "track thermal load" works as expected. Has anyone else had this problem or found a solution?


Senior Energy Analyst

Taitem Engineering, PC
110 S Albany Street, Ithaca, NY 14850
Voice: (607) 277-1118 x110

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Joined: 2011-09-30
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