View Full Version : BAC...and water source heat pumps
09-25-2006, 11:00 PM
here is a job in a large condo complex in the Chelsea area of Manhattan,the 3 BAC towers handle the cooling in the summer with the middle tower doing some waterside econo for interior winter cooling loadshttp://img111.imageshack.us/img111/2397/mvc012ses3.jpg
09-25-2006, 11:05 PM
the 2 outer towers are drained down to within the building for the winter and the condenser pumps are valved over(still used)so the riser is looped thru steam heat exchangers to maintain 80F to 90F condenser loop for the heat pump cycle for heatinghttp://img166.imageshack.us/img166/5534/mvc015sym5.jpg
09-26-2006, 05:45 PM
Nice pictures and good to see a straightforward, simple design.
Smart to use the middle tower for the winter free cooling.
Renews my faith in Engineers.
And the 80 - 90 degree steam tempering works how?
09-26-2006, 05:46 PM
I guess that's city steam in NYC?
09-26-2006, 07:17 PM
you run the return condenser loop past a steam heat exchanger to maintain the loop temp at 80 to 90...had the same application up in the norhtern suburbs except.they had 2 commercial hot water furnaces tempering the water out on a temp controller set at 90F to cycle the boilers.so when the HPs go into heating they have a false load on the evaps.
09-26-2006, 08:22 PM
What brand of water source heat pumps are on this loop? I would expect to see some seriously high suction pressures while in heat mode with loop temps of 80 to 90 degrees- typically 85 to 90 psi. Most of the loops I have been associated with operate at a maximum temp of 70 degrees during the winter.
09-27-2006, 06:34 AM
What was your vantage point when to you snapped these pictures. Are you really a mild mannered HVAC mechanic in disguise? Who came to earth to fight the phase out of R-22 in the American way. Able to leap tall buildings in a single bound. Faster than a streaking shemale in the meat packing district on 14th Street. Only a true New Yorker will know what that last one means. How come the two outside towers don't have their lines insulated like the middle tower? I wouldn't want to service those a/c units above and behind the towers. You really must be Super Maxster. Look up in the sky it's a jet, it's a plane oh no it's just that a/c guy again.
09-27-2006, 02:17 PM
I'm assuming they are closed circuit coolers. Do you drain the pan water from the middle tower in the winter? I have also always seen 70° loop temp in the winter.
09-27-2006, 05:06 PM
The last few wshp jobs I have done I am setting up the winter loop temps around 65F. Trane claims that this is most economical. I use 90ish for summer.
09-27-2006, 06:51 PM
the middle tower is for waterside econmizing in the winter for the gyms and larger rec areas within,
09-27-2006, 07:13 PM
my name is Frank, and I am a pipefitter in Kansas City. We don't have alot of cool stuff like that. How tall is that building, what size is the chiller and do you have any other pictures?
09-27-2006, 08:28 PM
Maxster- thanks for the pictures. I too would like to see any more that you might have.
So they are using a convertor to temper the water and addressing the tempering on the return, rather than the supply side. I guess this is easier to control than the usual 78 degree supply side temp.
That would explain the questions about the supply temp requirements. Get the return temp right and the supply will take care of itself.
Can I guess that there is a seperate water loop between the steam convertor and a plate and frame heat ex. that is proportionally controlled by a mixing valve to maintain the required temp?
And the other two towers, being drained during the off season, do not require pipe insulation?
Betcha BAC would like a copy of those picture$$$$.
[Edited by atmosphere on 09-27-2006 at 08:32 PM]
09-28-2006, 07:34 PM
basically your taking that return from the HP water return and exchanging it thru a steam fed heat exchanger,and the TC-1 setpoint maintains the setting of between 85F-90F as it goes back up into the supply to put a load on the HP while in the heating mode...no tower is in use during the winter only that middle one for econo cooling to larger unts with condensers and waterside econos 45F-50F range with a TC-1 on that supply to the house and cycles fan to maintain that setpoint
09-28-2006, 07:58 PM
great pics, never seen towers surrounded by trees, benches and a nice fence.
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