Re: [EnergyPlus_Support] Condenser Loop and Cooling Tower

Qianmin

On Thu, Aug 4, 2011 at 1:40 PM, YuanLu Li <yli006@xxxxxxxxxxx> wrote:

See my comments below.

When the simulation is running, make small changes and watch the temperature variation at the system nodes.

You may stop the zone system and watch the tank operation by reducing its insulation, so that it will cool down to a zone, where it is mounted. This will give you some idea of the heat or cool storage relative to the room size.

When running DesignDay simulation there may be some strange temperature values, because some registers are not cleared at the end midnight, and the same value appears on the starting midnight. As soon as the system is enabled, the value will jump to the operting level. By having a heat leakage, you can see the tank temperature changes slowly and confirm that the schedule is running.

Dr. Li

To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: zqianmin@xxxxxxxxx

Date: Thu, 4 Aug 2011 11:35:56 -0700

Subject: Re: [EnergyPlus_Support] Condenser Loop and Cooling Tower

I'm going to try modified the RadLoTempCFloHeatCool.idf, move all the condenser loop related objects to plant loop objects, and see if there is any different in the results.
Because EPlus allow you to control more variables, you must watch the selection of set point manager and available manager carefully. Make them simple first.

I will change all the equipment using autosize after it to check the results.
For lowRadiantPanel, the water temperature range may not be the same as the normal four pipe fan coil unit. You need to watch that for autosizing.

The only different I can tell is the "Loop temperature setpoint node name or reference", there are two additional selection of "air and ground" in condenser loop object. It says this node is used by loop manager to maintain the temperature. So that is something considering bypass pipe, right? Bypass pipe is normally selected for the use of the constant volume pump. If it is not required, the simulation would ignor it.

If you are using a storage tank, you need to watch this component as well.

The ground may be a virtual GSHE value. If it is your buried tank would have a lower temperature for this field.

Because "air" and "ground" temperature are from weather file, not a temperature we could define in schedule, so they are the special thing in condenser loop object. When you are using designDay simulation, the OA temperature is under your control. You can lower the ground temperature to below 18°C, and get a warning.

After I changed the condenser loop to plant loop, I have to choose condenser loop outlet node instead of Air to be the reference node. I'm not sure if this change will bring a big difference theoretically. In the condenser loop, the fan is the exhaust fan. You are monitoring the cooling capacity. When the condenser coil is not working, the fan speed can be reduced and turned off. In your case, the fan is to increase the charging rate, if you do use a storage tank, the fan would be on when the OD temperature is low. It is like the economizer. You want the outlet temperature to go as low as you can, therefore it may not be a set point value, set point and a delta..

On Thu, Aug 4, 2011 at 10:46 AM, YuanLu Li <yli006@xxxxxxxxxxx> wrote:

I expended the HVACTemplate-5ZoneWaterToAirHeatPumpTowerBoiler.idf in the exampleFiles directory.

The tower and water section is in the attached text file.
The templates are expanded to many branches and control objects.

The hot and cold water was applied to the heat pump. In your case, the hot and cold water will be applied directly to the zone coils.

I do not know whether you can do this direct substitution.

Dr. Li

To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: zqianmin@xxxxxxxxx
Date: Thu, 4 Aug 2011 10:01:29 -0700
Subject: Re: [EnergyPlus_Support] Condenser Loop and Cooling Tower

I just tried using plant loop instead of condenser loop. and it works!! generate the correct .svg file.
I didn't use any object related to condenser loop.
The reason I did that because it gave me this error before and seem I can't put tank in condenser loop demand side.

ThermalStorage:ChilledWater:Stratified = TES TANK:
** ~~~ ** ...match to PlantLoop not found.
** ~~~ ** ...could not find matching PlantLoop for BranchList=CONDENSER DEMAND BRANCHES.

On Thu, Aug 4, 2011 at 9:51 AM, Karen Walkerman <kwalkerman@xxxxxxxxx> wrote:

"Why I can't use plant loop instead of condenser loop? "

...because whoever wrote the software made it that way...

On Thursday, August 4, 2011, Qianmin Zhang <zqianmin@xxxxxxxxx> wrote:
>
>
> So I have to use condenser loop to define the loop with cooling tower?
>
> Why I can't use plant loop instead of condenser loop? Condenser loop has less input than plant loop. Thank you for your response.
> Qianmin
>
> On Thu, Aug 4, 2011 at 8:58 AM, Richard Raustad <RRaustad@xxxxxxxxxxxx> wrote:
>>
>>
>>
>> Yes, use the condenser loop object. In addition to the tower, you should also be connecting some equipment in the plant loop to this condenser loop. The software treats these loops separately through calling subroutines in the program.
>>
>> On 8/4/2011 11:34 AM, Qianmin Zhang wrote:
>>
>>
>>
>> Do I have to use the object of condenser loop if there is a cooling tower in the plant?
>>
>> What the purpose to separate the condenser loop from all other plant loop in energyplus?
>> In input and output reference, both plant loop and condenser loop have similar structure diagram (fig 62 and fig. 63)
>>
>> --
>> Richard A. Raustad
>> Senior Research Engineer
>> Florida Solar Energy Center
>> University of Central Florida
>> 1679 Clearlake Road
>> Cocoa, FL 32922-5703
>> Phone: (321) 638-1454 <tel:%28321%29%20638-1454>
>> Fax: (321) 638-1439 <tel:%28321%29%20638-1439> or 1010

>> Visit our web site at: http://www.fsec.ucf.edu
>>
>> UCF - From Promise to Prominence: Celebrating 40 Years
>
>