Recent content by scha0786

Randomusername - you are correct that the humidity sensor is in the exhaust air stream at the DOAS unit. you are not correct, no space humidity sensors are being installed. Yes I have contacted. THe response I received is exactly what lilluput1 typed, lol. Maybe this is a common design now...

Further movement on this. The design firm clearly wants this sequence to happen. When return air humidity rises above set point (55% RH), the chilled water valve modulates open as a function of deviation from set point. I my mind, won't this make the situation even worse because now you could...

I agree that they need some sort of reheat after the cooling coil. Since the unit is chilled water it would have to be a sensible wheel or a run around loop. Another option that they could have done was used a desuperheater on the air cooled chiller for reheat of the two DOAS units.

Random - The design supply air is 55F in lieu of 50F and the space design of 75F 50% RH, how can that 50%RH be maintained without sending dryer air to the space. When the cooling is on and condensing water out of the air the supply air will be more like 54F and 95% RH.

its 60 cfm per ACB, so each room has roughly 480 cfm of primary air.

Oh and that reminds me, they don't have space humidity sensors. So the only way they are controlling the high temp chilled water is based on the return air back at the DOAS. I have been asking for a final sequence of operations from the engineer because the initial sequence that went out to bid...

each room has 6 ACBs with a design of 60 cfm of primary air.

climate is southwest MN and no heat source prior to the wheel in the exhaust stream. I really think this is going to be a problem and have raised my concerns but no one seems to care as it is a new school. But I guess I will get the last say because I will be doing the Cx.

Doing a design review of a 90,000ft^2 two story building with DOAS serving chilled beams in classrooms. Currently there is an ERW that has a configuration of: first a dissicant wheel then the heating coil and finally the chilled water coil. The rooms typically have one wall exposed with 70%...

just to cool the heat from the equip you will need roughly 3700 cfm. If I were you I would look at supplying 3700 cfm and not exhausting. Supplying air and distributing via ductwork will help mix the air better in the room. I would do a quick cooling and heating load on the room. If you have...

Ok, so I did my Trane Trace 700 load calc and it spits out 8.9 tons of cooling required. Going with a 10ton Liebert DS THANK YOU FOR ALL THE HELP!!! now I just have to sell this to the customer, lol

I agree with KiwiMac, I just looked at the picture I have from the UPS nameplate and AC output = (AC output 120/208 30 KVA 60 Hz 83.4 amps 3 phase 24 KW at 0.8 PF) See attached pic So what I am going to do is use the 24 KW as my server load, I looked up the data sheet for the UPS and the heat...

mintjulep, Thats what I would say but I will have to get my electrical engineer involved i guess, lol. He'll be able to tell me what voltage is going on.

ok so now I am kinda confused. I asked the IT people what there total amp draw is at the UPS. They told me 90 amps. So do take 120 * 90 = 10800 watts divide by 1000 = 10.8 kW * 3,412 = 36849.6 btu/h divide by 12,000 = 3.07 tons? I am confused if I use 480, 208 or 120 to get the watts? The UPS...

yeah it is a pretty big room. Currently they have a liebert DH192 in it (10 ton). they have a false floor with floor supply set up. Unfortunately they only have one unit, this past summer the unit sprung a leak on the glycol side and they had no way to shut it down for repairs or the whole camp...