How have you been?
I read about the Heat Pump Water Heater documentation´s and I share my views with you. Since we can have an water tank located outdoors or zone, even as DX Coil, I took the example file of E+ (HPWH) where show five different Heat Pump Water Heater (in zone both zone air and outdoor air, in zone using only zone air, outdoors, located outdoors and connected to a water plant loop and scheduled).
I took this example and clean all most examples heat pump water heaters except the example of located outdoors and connect to a hot water plant loop, I run this simulation and when I looked to the Output Variables, I can saw values in DX Coil Crankcase or DX Coil Total Water Heating Rate.
This example increased my mystery, so I decided share my problems with this system heating to all users E+ (which I´m glad for your help!) and perhaps someone can tell how fix this problem or look at the file and figure out what´s wrong with the system...
Once upon a time thanks Mr. Dirkes!
Best Regards
From: "James V Dirkes II, PE" <jvd2pe@xxxxxxx>
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Cc: Fernando Silva <pintodasilva.fernando@xxxxxxxxx>
Sent: Tue, March 30, 2010 3:00:20 PM
Subject: RE: [EnergyPlus_Support] Re: Problems with Heat Pump AirToWater
Dear Fernando,
Some more thoughts:
· WaterHeater: Mixed shows an outdoor air node â??HPWHPlantTank OA Nodeâ??. This node is not included in your outdoor air NodeList. I do not know if thatâ??s a problem, though.
· Your fan is upstream of the DX coil, so itâ??s different than the IO Reference example, but I do not think that is a problem.
· The IO Reference discussion for the for WaterHeater: HeatPump says,
I do not think that you have your nodes connected to the plant loop, so perhaps that is the problem.
I cannot spend more time on this problem today, but I hope that I have been some small assistance. I am happy to help as time permits!
The Building Performance Team
James V. Dirkes II, P.E., LEED AP
1631 Acacia Drive NW
Grand Rapids, MI 49504
616 450 8653
From: EnergyPlus_Support@ yahoogroups. com
[mailto:EnergyPlus_ Support@yahoogro ups.com] On Behalf Of Fernando Pinto
da Silva
Sent: Tuesday, March 30, 2010 7:18 AM
To: EnergyPlus_Support@ yahoogroups. com
Subject: Re: [EnergyPlus_ Support] Re: Problems with Heat Pump AirToWater
Dear James V. Dirkes II,
Firstly, my apologies, because when I wrote the message was earlier in my city.
I understand what you mean and I´m completely agreed with this point. When I
look at the example file and I see that this advice don´t needs an object such
as WaterUseEquipment. The load rate of water it´s make by the DX compression
system. The nodes water mixed side´s will be used in the branchs to supply the
water to the coil cooling water of the air handling unit (as you see in the
attched picture file).
This connection will be used because the DX compression system is considered
the primary heat source and the tank´s heater provides supplemental heat as
necessary, but how I can see there´s no any value or load to the DX Coil Water
Heating Rate, and the nodes of condenser it´s correct between DX coil and the
water tank of the HPWH. I tried modelling the same system with the examples
files of program (HPWH) and I can not see any deffirences between the files...
I apologize again for taking your time.
Thanks for your attention and support
Best Regards
From: "James V Dirkes II, PE"
<jvd2pe@xxxxxxx>
To: EnergyPlus_Support@ yahoogroups. com
Cc: Fernando Silva <pintodasilva. fernando@ yahoo.com>
Sent: Tue, March 30, 2010 11:20:28 AM
Subject: RE: [EnergyPlus_ Support] Re: Problems with Heat Pump AirToWater
Fernando,
I understand better now.
Consider:
I do not see any object which uses the water such as WaterUse:Equipment. If there is no water use, the load will be zero.
In this case, HPHW Use Inlet Node must be connected to a water use.
(I cannot spend more time on this for several hours. I hope this helps!)
WaterHeater: Mixed
Coil:
WaterHeater: HeatPump
The Building Performance Team
James V. Dirkes II, P.E., LEED AP
1631 Acacia Drive NW
Grand Rapids, MI 49504
616 450 8653
From: EnergyPlus_Support@ yahoogroups. com
[mailto:EnergyPlus_ Support@yahoogro ups.com] On Behalf Of Fernando
Silva
Sent: Tuesday, March 30, 2010 4:52 AM
To: EnergyPlus_Support@ yahoogroups. com
Subject: [EnergyPlus_ Support] Re: Problems with Heat Pump AirToWater
Mr. James V Dirkes II
I´m glad and aprecciate your atention gave in this simulation!
I understand what you mean and I agree with you when I talk about
HeatPump:WaterToAir , but in this case it´s AirToWater, I will explain below.
About the heating system, In my simulation I have an Heat Pump Water Heater,
this object provides a model taht is compound object consisting of a water
heater tank, a direct expansion (DX) "coil" and a fan to provide air
flow. In my case the location of DX Coil compressor it´s outdoor and the water
heater tank it´s located in the zone.
Following the documentation and the example file (HeatPumpWaterHeate r file) I
don´t have use AirLoopHVAC, because in the field of Heat Pump Water Heater I
connecting the three components (DX Coil, Water Heater tank and a fan.
My question it´s still I have use an AirLoopHVAC, since the DX Coil has been
connected to the WaterPumpWaterHeate r!? Now I´m a little bit confused... Can
you explain better this procedure...
Thanks for your support and atention!
Best Regards
--- In EnergyPlus_Support@
yahoogroups. com, "James V Dirkes II, PE" <jvd2pe@...>
wrote:
>
> Fernando,
>
>
>
> You have not connected the DX heating coil to any equipment or AirLoop.
The
> only heating coil you are using is the Coil:Heating: Water object. If you
> want to use the DX coil and a Heat Pump, you'll have to use a
> AirLoopHVAC: UnitaryHeatPump: WaterTo Air object.
>
>
>
> This object assumes that you also use a DX coil for cooling, so you may
have
> some difficulty. I think that a chiller and a HeatPump don't normally get
> used at the same time.
>
>
>
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>
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