[Equest-users] No Heating from PVVT Heat Pump
Chris Jones
cj at enersave.ca
Thu Sep 30 06:26:28 PDT 2010
The best way to "understand what is going on" is
to examine the INP files to find how the system
is defined. That will help you to understand how
the simulation engine works. equest is a front
end to DOE2.2. It is a good idea to become
familiar with the DOE2.2 keywords and how they effect the model.
At 04:35 PM 29/09/2010, Eddie Corwin wrote:
>I will continue on with you suggestions. I is
>just hard for me to get past the idea that when
>all of the HVAC systems are auto-sized, I still
>have many unmet hours. If it were just a few
>unmet hours, I would be ok with it, but this
>system has more than a few unmet hours.
>
>The problem seems to be in the "WL/GS Ht Pump"
>input. There is no DOE2 help on the topic, so
>it is hard to know exactly what is going on, but
>when it is set to "NO" The HP runs in heating
>mode for ~1600 hours (with many unmet
>hours). When the option is set to "YES" the
>heat pump runs for 3218 hours in heating mode
>(with very few unmet hours). It seems that this
>option determines weather or not the heat pump
>is able to operate at low outdoor temperatures,
>or something along those lines. With the option
>set to "YES" I am still able to have an
>air-cooled condenser, and I still have curves
>that relate the EIR and capacity to the OA
>temperature. If you want to try this out, I have attached the latest model.
>
>Again, thank you for your suggestions, I always
>find it very helpful to have a 3rd party's comments
>
>-Eddie
>
>
>From: "Bishop, Bill" <wbishop at pathfinder-ea.com>
>To: Eddie Corwin <ecorwin at altanova-energy.com>
>Cc: equest-users at lists.onebuilding.org
>Sent: Wed, September 29, 2010 3:56:31 PM
>Subject: RE: [Equest-users] No Heating from PVVT Heat Pump
>
>Eddie,
>
>You can see with your attached model that at
>least you are getting heating and the system is
>operating. To get rid of your unmet hours, you
>will have to refine the model. First put the
>accurate loads and envelope in (including
>getting rid of the exterior floor I mentioned
>previously) and make sure your schedules
>(lighting, equipment, occupancy etc.) are
>reasonable. Then change some interior walls to
>air walls as applicable (interior walls that
>aren’t actually there, such as corridors that
>open into a space without a door) to more evenly
>distribute loads within each floor. Finally, add
>system capacities and zonal air flows. Perimeter
>baseboard heating may be needed in the design if
>the windows and walls are as poor as your
>previous attached model suggests. You might also
>create a custom capacity curve (HEAT-CAP-FT) for the Mitsubishi heat pump.
>
>Regards,
>
>Bill
>
>
>
>William Bishop , PE, BEMP, LEED® AP | Pathfinder Engineers & Architects LLP
>
>Mechanical Engineer
>
>
>
>134 South Fitzhugh Street
>Rochester, NY 14608
>T: (585) 325-6004 Ext. 114
>F: (585) 325-6005
>
>wbishop at pathfinder-ea.com
>
><http://www.pathfinder-ea.com>www.pathfinder-ea.com
>
>P Sustainability – the forest AND the trees. P
>
>
>
>----------
>From: equest-users-bounces at lists.onebuilding.org
>[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Eddie Corwin
>Sent: Wednesday, September 29, 2010 2:15 PM
>To: equest-users at lists.onebuilding.org
>Subject: Re: [Equest-users] No Heating from PVVT Heat Pump
>
>
>
>Bill and Kelly, thank you for your input.
>
>
>
>Bill:
>
>I have tried using the wizard to create the PVVT
>heat pump. I even used "system per zone" so
>that each zone is controlled
>independently. Even coming strait out of the
>wizard, there are plenty of heating hours not
>met. I understand that a stand air-to-air heat
>pump will be unable to operate in very cold
>weather, but that is where the supplemental heat
>should take over to get rid of any unmet hours. I have attached this model.
>
>
>
>The actual system I am trying to model is the
>Mitsubishi Hyper Heating Inverter Y-Series Heat
>Pump. This system (in heating mode) uses
>electric resistance heat to warm the outdoor air
>before it reaches the outdoor coils. This
>ensures that heat transfer will occur between
>the OA and the outdoor coil, and allows for
>operation at temperatures as low as -13*F. At
>first I thought that eQuest can not exactly
>model a system like this, so maybe eQuest is not
>allowing any heat transfer between the cold coil
>and the cold air. But then I tried again using
>the RESVVT, and it seems to work well, even in
>the middle of winter. My only objection to
>using the RESVVT is that I would like to have control over the OA.
>
>
>
>Kelly:
>
>
>
>You say that I can not use PVVT with an air
>cooled compressor, but it says that it is
>possible in the DOE2 help file, also, the wizard
>will set it up that way. Normally I would just
>use the PSZ or even PTAC to model an air-to-air
>heat pump, but I would like to use the variable
>speed compressor, so I need to use a VVT system.
>
>
>
>
>
>Has anyone modeled an air-to-air HP system that
>operates at such low temperatures before?
>
>
>
>Thanks,
>
>
>
>-Eddie
>
>
>
>
>
>
>
>From: Dakota Kelley <dakotak at teliospc.com>
>To: Eddie Corwin <ecorwin at altanova-energy.com>;
>equest-users at lists.onebuilding.org
>Sent: Wed, September 29, 2010 12:56:13 PM
>Subject: RE: [Equest-users] No Heating from PVVT Heat Pump
>
>Water-cooled heat pumps, ground loop or not, are
>considered system type PVVT. Air-cooled heat
>pumps are considered type PSZ. Try changing
>your system type to PSZ and your heating source to “heat pumpâ€.
>
>
>
>You can also create a temporary project and set
>up an air-source heat pump in the wizard, then
>go inspect the system type/settings in the
>detailed interface to see how eQUEST interprets your inputs.
>
>
>
>Thanks,
>
>
>
>
>
>DAKOTA KELLEY
>
>Project Designer | Energy Analyst
>
>
>
> Office: 214.744.6199
>
> Cell: 214.280.3825
>
> Fax: 214.744.0770
>
>
>
><http://www.teliospc.com/>http://www.teliospc.com/
>3535 Travis St. Suite 115
>
><mailto:dakotak at teliospc.com>dakotak at teliospc.com
>Dallas, TX 75204
>
>
>
>| MEP ENGINEERING · ENERGY MODELING · LEED CONSULTATION · COMMISSIONING |
>
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>From: Eddie Corwin [mailto:ecorwin at altanova-energy.com]
>Sent: Wednesday, September 29, 2010 8:43 AM
>To: equest-users at lists.onebuilding.org
>Subject: Re: [Equest-users] No Heating from PVVT Heat Pump
>
>
>
>So I determined why I was not getting any
>heating, and the resolutions perplexes me.
>
>
>
> I am modeling an Air-to-Air heat pump, so in
> the air-side system --> Basics tab I selected
> "NO" for the field "WL/GS Ht Pump". In doing
> so, I get no heating out of the system. When I
> change the field to "YES" I now get
> heating. Attached are two images showing the
> field i am referring to, and showing that I
> have an air-cooled condenser. Does anyone know
> why this might be happening. I am worried that
> eQuest is treating my HP like a ground or water
> source HP instead of an air-to-air system. Any
> thoughts on the matter would be
> appreciated. By the way, I am using eQuest 3.64
>
>
>
>-Eddie
>
>
>
>
>
>From: Eddie Corwin <ecorwin at altanova-energy.com>
>To: equest-users at lists.onebuilding.org
>Sent: Tue, September 28, 2010 5:17:21 PM
>Subject: [Equest-users] No Heating from PVVT Heat Pump
>
>I am trying to model a PVVT system, that uses an
>air-cooled heat pump for heating and
>cooling. For some reason, the system refuses to
>supply any heating. When I change the condenser
>type from air-cooled to water-cooled, the system
>WILL provide heat. Has anyone experienced
>problems like this, or has someone successful
>modeled a PVVT air-cooled heat pump? I have
>attached my IDF and PD2 file for review.
>
>
>
>
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Chris Jones
14 Oneida Avenue
Toronto, ON M5J 2E3.
Tel. 416-203-7465
Fax. 416-946-1005
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