Loop to loop heat pump

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Dear eQUEST users,

I am modeling a loop to loop heat pump in the eQUEST and it needs to
attach hot water loop&pump, chilled water loop&pump, condenser water
loop&pump. After I create these loops and pumps, there is an error in
simulation shows "Hot water loop has zero design flow. Check input for
consistency, or specify design loads.". But I did connect heat pump to
hot water loop. Is there anything I need to input so that the simulation
will be successful? Does anyone have the experience of modeling a loop
to loop heat pump? It's my first time model heat pump, any help and
suggestion will be appreciated.

Best regards,

KeHuang Chen

Chen Ke-Huang's picture
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Joined: 2011-09-30
Reputation: 0

Without looking at the model, it would seem that eQUEST cannot size the
heating loop. The default for loop sizing is "secondary" where eQUEST
simply adds up the capacity of the coils attached to the loop (not good
I know -- apparently that is in the works in an upcoming version). The
error message suggests there is no heating elements to count up.

The issue I have had with loop-to-loop heat pumps is and imbalance
between the loads/temperatures. On the 4th tab/screen of the
loop-to-loop chiller type there are 4 temperatures (OK 2 temps and 2
delta T's) that are key to getting this system to work. When I set
those to the values in the help file, my model ran. I am no expert on
this system type but did get "reasonable" (or at least so I thought)
values in the 1 building I did create that used it.

If you send your .inp and .pd2 I may be able to have a quick look.

Brian

bfountain's picture
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Joined: 2011-09-30
Reputation: 201

I have tried on many occasions to get a loop to loop heat pump to work,
with no success. If you really want to model a loop to loop heat pump, you
may have to use Energy Plus.

--
Karen

No Username provide's picture
Joined: 2011-09-30
Reputation: 200