Cooling Tower Plant and Water-Cooled Chiller

asked 2015-06-04 15:38:05 -0600

hugopft
723 ●1 ●11

updated 2015-08-08 09:50:32 -0600

I am modeling a water plant loop with a water-cooled chiller. To provide the required water to the condeser side of the chiller, I have created another plant loop where a place a cooling tower as can be seen below.

My first question is? Is this set up right for my case? Do I need to place a specific pump for this plant? Did I link the chiller plant right with my cooling tower plant?

Then, I have a concern regard to the results. After had simulated this model, I am getting as a result a HEAT REJECTION being added in the energy consumption of my model. Before get the results, I was thinking that my consumption with pumps would increase, and in fact it happened, and also my consumption with fans would increase, since the cooling tower system uses a fan to proceed with the heat rejection, but it did not. So, I am assuming that Heat Rejection is, in fact, the consuption of the cooling tower fan, am I right?

For the same exemple, in case I want only to analyse a VERTICAL BORE FIELD (Ground Heat Exchanger), to cool down the water, Is it right if I set a plant like in the picture below?

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A quick note in regards to your last comment (using geothermal as a heat sink). Beware when using the ground as only a heat sink and not also as a heat source. The system will work properly for a few years but the performance will likely start degrading after the ground temperatures become too warm. We recently worked on a project where the geothermal condenser had to be replaced with an evap system because the ground temperature rose too high and the system stopped providing enough heat transfer.

Lincoln ( 2015-06-05 12:59:41 -0600 )edit

how do you connect the chiller to the condenser loop? I tried but the chiller doesnt have the dots like your.

obuchely ( 2015-10-17 13:12:56 -0600 )edit

@obuchely, set the two plants loops: one with the chiller and other with the cooling tower. Then, with the cooling tower loop opened, go in the right tab, choose the option MY MODEL and drag the Chiller that you have in there to the cooling tower loop. Hope it´ll work properly.

hugopft ( 2015-10-19 05:44:19 -0600 )edit

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answered 2015-06-04 17:43:52 -0600

TaylorRoberts

2933 ●1 ●2 ●14 http://www.group14eng.com/

You do need a pump for the condenser loop and Heat Rejection is the cooling tower energy use. Both of your condenser loops look set up correct.

Please note, it is very important to make sure your sizing information for the plant loop (click on the dotted line to access this) and your setpoint managers are set up correctly. Both your pictures have a scheduled setpoint manager, which I assume is fixed. You might want to change those if your plant loops have temperature resets.

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First of all, thank you very much Taylor Roberts. I clicked on the dotted line and the option LOOP TEMPERATURE SETPOINT NODE NAME has the same node name of my SCHEDULE SETPOINT MANAGER. So, I did not understand what you meant by "change those if your plants loops have temperature resets". I really appreciated that!!!Thanks again.

hugopft ( 2015-06-05 13:12:15 -0600 )edit

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