RE: [EnergyPlus_Support] Re: Problems with Heat Pump AirToWater

Dear Fernando,

Some more thoughts:

· WaterHeater:Mixed shows an outdoor air node “HPWHPlantTank OA Node”. This node is not included in your outdoor air NodeList. I do not know if that’s a problem, though.

· Your fan is upstream of the DX coil, so it’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@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of Fernando Pinto da Silva
Sent: Tuesday, March 30, 2010 7:18 AM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
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@xxxxxxxxxxxxxxx
Cc: Fernando Silva <pintodasilva.fernando@xxxxxxxxx>
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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