[BLDG-SIM] Trouble with Heat Pumps (eQuest)

[Karen Walkerman]

Thanks for all the responses.  I think I figured it out:

When you choose "WLHP" in the eQuest Wizard, it creates a PVVT system with a
GSHP.  The curve used to adjust HIR is based on a few data points, and did
not perform very well at the temperatures I was using.  A straight HP system
selected in detailed edit mode did much better.  I now realize that this is
because the HIR curve was better for my purposes.  I have now created curves
based on the heat pumps spec'd for this job and the numbers are making more
sense.

Thanks again for all the repsonses, thought I'd let everyone know,
especially because PVVT is what is selected when you create a WLHP system
with the wizard, and may need some detailed data edit tweaking.

~Karen~


On 8/6/07, Brandon Nichols <BrandonN at hargis.biz> wrote:
>
>  Hello Karen,
>
> "When so many things can go wrong, almost certainly more than one of them
> will go wrong at the same time" ... or something like that, according to
> Murphy.  Recently I have been wrestling with a large heat pump system, and
> may be able to help a little.
>
> Have you adjusted your heat pomp efficiencies?  Ground and water source
> heat pumps will have different efficiencies, if for no other reason than
> they are operating with different condenser water temperatures.
>
> Check this post...
>
>
> http://elcca-exchange.blogspot.com/2007/03/ground-water-source-heat-pumps.html
>
> Next suspect, schedules... don't have a post for that yet, let me know the
> effect of efficiency adjustments and we'll go from there.
>
> Regards
>
>  Brandon Nichols, PE
> Mechanical
> *HARGIS ENGINEERS*
>
> 600 Stewart Street
>
> Suite 1000
>
> Seattle, WA 98101
>
> www.hargis.biz
>
>
>
> *d |* 206.436.0400  *c | *206.228.8707
>
> *o |* 206.448.3376  *f  |* 206.448.4450
>
>
>
>  ------------------------------
> *From:* BLDG-SIM at gard.com [mailto:BLDG-SIM at gard.com] *On Behalf Of *Karen
> Walkerman
> *Sent:* Friday, August 03, 2007 5:20 PM
> *To:* BLDG-SIM at gard.com
> *Subject:* [BLDG-SIM] Trouble with Heat Pumps (eQuest)
>
>
>  I apologize for all the emails I've sent out as of late.  Thanks for all
> the input.
>
> I have another:
>
> I'm comparing a ground source heat pump to a heat pump loop with chiller
> and boiler.  Trouble is, when I switch systems, the energy used by the heat
> pump to heat the space goes down only slightly as compared to the energy
> input by the boiler.  My loop temperatures change between the systems (from
> heating temp of 40 F to 70 F), and COP rises accordingly.  Right now the
> energy use of the two systems is off by about 85%!!
>
> Energy use for straight electric resistance heat is about the same as the
> electric use for a heat pump system.  This is for a baseline model with 18%
> evenly distributed windows, R-19 batt insulation, R-38 ceilings, etc.
>
> I used the wizard to set up the equipment for all runs (I'm also having
> trouble in detailed edit mode).  The water loop and the heat pump don't seem
> to be talking to one another.  Can anyone help?
>
> Thanks,
>
>
> --
> Karen Walkerman
> Second Law Consulting
> 802-238-0980
> kwalkerman at gmail.com
>
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>


-- 
Karen Walkerman
Second Law Consulting
802-238-0980
kwalkerman at gmail.com


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