cant seem to find the 90degree discharge on ASHRAE 62.1, but there is one on ASHRAE 90.1-2016 for difference on supply temperature to room temperature.
@TECTubefilms4 ай бұрын
Technically it is not a rule for 90 degree max SAT, but rather 15 above space temp. Most spaces seem to average a 72 degree heating setpoint so that comes to 87 max supply air and because most of us like to think about even numbers, we end up with 90. In ASHRAE 62.1-2019 look at section 6.2.1.2 for Zone Distribution Effectiveness. The Ez calculation uses 0.8 multiplier for "Ceiling supply of warm air 15°F (8°C) or more above space temperature and ceiling return," which mathematically increases your minimum OA ventilation by 25% from what it should be.
@ral1534 ай бұрын
@@TECTubefilms now i get it, i really need to dig more Ashrae 62.1, Thank You so much! More power to you guys at TECTUBE! 💓
@caffeinatedinsanity23242 ай бұрын
Yeah an engineer taught me this recently. Hot air stratification is definitely a problem that results in wasted energy
@Freemanr250 Жыл бұрын
Would reduced airflow across the dx coil, when the boxes close, cause possible flood back at the compressors? Is there additional sensors on the ddc to monitor suction temp/pressure?
@TECTubefilms Жыл бұрын
Each VAV box controller is set with a minimum and maximum CFM that it can modulated between. The sum of the minimum CFM settings for all of the VAV boxes must add up to the minimum CFM required by the AHU or RTU.
@thomascrane81307 ай бұрын
How do you check if the amount of air being delivered is enough? Do they size the max by air changes per hour or l x w x 1.2? I have heard both please help!
@TECTubefilms7 ай бұрын
No, sizing is not by air changed per hour. Nor is it by room dimensions. Although both of those are part of the overall calculations. The design engineer does a heat gain calculation (aka a load calc) for that zone adding up all the sensible and latent heat sources (walls, windows, computers, etc) on a "peak design" climatic day to determine how many BTU/h need to be removed from the space. This is almost always done with software and no one calculates by hand anymore. Then assuming a 55F supply air temp, uses that temp and the required BTU/h to calculate the required CFM of air needed.
@anthonyrodriguez2432 жыл бұрын
Where do we go to sign up for training
@TECTubefilms2 жыл бұрын
What type of classes are you looking for and in what city?
@anthonyrodriguez2432 жыл бұрын
Automation
@TECTubefilms2 жыл бұрын
@@anthonyrodriguez243 Automation classes are generally very specific to the brand of controllers, and even their vintage. At our offices in the Chicago and Milwaukee area, we train Carrier commercial controls dealers on the Carrier OPEN BACnet system. The Level 1 class meets one day per week for 7 weeks. The next one is in Melrose Park, IL and starts in October. The Carrier factory has similar classes in the Atlanta area and sometimes Syracuse.
@Sechelanji Жыл бұрын
How do you determine the location that allows for a setpoint 1.2 or less
@TECTubefilms Жыл бұрын
If you are the design engineer, you can determine that by the pressure your fan will be generating and the pressure drop of the devices it is pushing air thru, including coils, elbows, adapters, etc. If you are the installer, you can run the system, and use a manometer to sample a locations in the duct.
@caffeinatedinsanity23242 ай бұрын
VAV damper boxes with fans in series... I wonder if these could borderline work as a fan coil unit
@TECTubefilmsАй бұрын
No. Series fan powered boxes lack a cooling coil and drain pan
@timothyrichardson85678 ай бұрын
So How Do you Trouble Shoot A VAV box for Heating cause i have a situation for patient room is staying cool when i want the room heated
@TECTubefilms8 ай бұрын
VAV, by definition, is a cooling only system at the air handler level (other than a brief morning warm-up). Does your VAV zone box have its own local zone heater such as electric resistance or hot water coil, separate from the main air handler?
@timothyrichardson85678 ай бұрын
@@TECTubefilms Yes it is separate from the heating Element System so How do I keep that uint Warm except early morning when the unit needs heat
@TECTubefilms8 ай бұрын
@@timothyrichardson8567 What is "separate from the heating element?"
@TECTubefilms8 ай бұрын
@@timothyrichardson8567 To be clear, to heat the VAV zone you are talking about that specific VAV zone needs its own local heater separate from the morning warm-up heater that is in the main air handler and shared with all zones. So you need an electric heater instead the VAV box or on the baseboard permitter of that zone.
@timothyrichardson85677 ай бұрын
@@TECTubefilms So Where Can I go to receive training for this particular units for my job and are the classes online or in person.
@alvarohernandez7571 Жыл бұрын
Can you create one of ge Ptac heat pump please
@TECTubefilms Жыл бұрын
We don't use GE products at our office. Plus PTACs are pretty straightfoward... they all have the same dimensions and they just plug into the wall. No one services them anymore either... the hotel just swaps them out if they fail.
@MR-backup10 ай бұрын
If you start being politically correct, I will stop watching your videos. 1:20 Basics 1:50 Multi Zone System 12:35 VAV Breakdown 1:18:30 VAV Rules 29:02 Zone Layout 43:35 Minimum Outside Air Question 47:50 Inlet Guide Vanes 52:40 Affinity Laws 1:03:30 Compressor Capacities 1:11:40 Hot Gas By Pass 1:50:00 Digital Scroll 1:25:54 Energy Savings 1:30:00 VAV types Also, if you have motors (fans) that are rated for higher Hz, then it's fine to run it's VFD at higher Hz.