Smali1, it is customary to de-couple the Loads - Sensible & Latent. The Fan Coil will cater to just the Sensible Load and the Latent Load would be taken care of by a separate small duct which will bring in Treated Fresh air from a Central Air Handler. This way, you will be able to limit the size...
Hey Everyone,
I encountered a peculiar situation at one of our sites. Using Pressure Independent VAVs with a Centralized Air Handler. Noticed that on a few VAVs, when the AHU is shut-off, the Controller is registering a negative flow on the BMS. In a System with about 35 VAVs, this is happening...
Look at using cupro-nickel condensers (shell and tube).
Piping could be HDPE.
Go below the low tide line.
Look at local environmental laws and codes.
Filtration.
These are some of the key issues.
Need to probably look at de-scaling more frequently
Thanks, guys.Most Terminal Manufacturers do provide throws to Terminal Velocities of 50-100-150 FPM. I just wanna check if there is a method to evaluate the ditance at which the velocity could be a pre-determined value.
The idea would work fine if the RH is low (around 20 ~ 30%) on cooling days with high outdoor DB temps. We do this on Big Chillers here in some parts of India where the summers are dry.The only thing to keep in mind is that the Condensor Fan must be able to overcome the increased static. You...
Rather than using a thumb rule, I guess it is quicker and safer to do a load calculation. All you need is to factor in the fabric load and the Motor Load. Fresh Air would be Zero. No Occupancy and minimal lighting.
I agree. Internal lining is no longer the order of the day considering IAQ ssues. Remember, in most cases only the initial length from the Unit outlet is lined to attenuate he Fan Sound in Duct. This is better addressed using Attenuators. External Insulation is provided to limit rise in...
Hi,
I assume that the Split Unit would be a DX Coil, and, that the Coil depth will not probably be more than 3 row deep. In your case since he total Enthalpy of the Room is lower than the Unit Capacity, it should do the job, albeit at a slightly elevated DB with lowered RH. You will still be...
Hi. Does anybody know of a mathematical method of computing the velocity of air at a specified distance from the Air Outlet ? Application is a Laboratory where we need to maintain a velocity of 20 FPM at the Occupied Zone. Temperature of primary air being supplied will be about 55 deg F...
By ventilation, I presume you are refering to Outside Air. Considering that most public places do not permit smoking, you could tune down the air quantity to 15 CFM per person. In public spaces where occupancy tends to swing between extremes, it is appropriate to use demand based ventilation...
As I have understood it, the mmajor tangible advantages of the Jet fan system are :
(1) No Ducting.
(2) Saving in height (from construction point of view) since ducts need not be factored in.
The other more significant advantage is -
In conventional system you would have a supply air fan and...
Assuming that everything else is as per design, and, that the AHU is new, motor is new, installation is proper, then it is very likely that the AHU Pulley may be sized for higher speeds. One easy way to check - if your Return is not ducted, just block the RA side and see if the increased static...
3 5.0 TR Unit should be delivering around 6,000 CFM. If they are Chilled water Units, then the grille area of 14 sq ft (even accounting for 50 % free area) should leave you with a Extract Air Velocity of about 850 FPM - good enough and should not create a noise issue. Probably the noise is from...
150 HP, with both the motor and driven machine in the space would mean you are looking at about 420,000 BTUs oer hour. So even if we are looking at all outside air and want to mainatain a differential with outside of 20 deg F, then we will be looking at about 19,500 CFM. For a room of this size...
For Fire Dampers, Fire & Smoke Dampers and Smoke Dampers, what is important is that all installation recommendations are taken care of (NFPA 90 guidelines, for example).
For Fire Dampers with Fusible Link, insist on UL Certified Fusible Links.
For Dampers with actuators, use a Control Panel...
Axial Flow Fans are OK, but how about the noise ? That is a serious disadvantage. If the area is not too large, just look at some simple propeller fans (wall mounted) which when located properly will do the job admirably at fairly low noise levels. All would depend upon your layout, area etc. If...
I go with ChasBean1. Any hazardous area will mandate negative pressure with respect to the surroundings for containment. I will sya, go with 10% less make up as compared to extract air. That should do the trick.
