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@anotherellis - "equations governing air flow in suction", this is not the volumetric flowrate equation, right? can you please tell me what is that equation?

@mechengcpe - discharge duct is 20x24. condenser air is 6000 cfm. velocity probably - 1800 fpm intake duct is 30x24. velocity is 1200 fpm.

@marcoh - they are horizontally separated, 12" apart. The Louver is 70"W x 25"H and our discharge and intake ducts are both 24"H. @mechengncpe - "I think no less than about 3000fpm on the discharge would prevent short circuiting." Do you suggest making the discharge duct a little bit smaller...

We have a project that use an indoor condenser. The intake and discharge are ducted to a Building Louver. They share the same louver. The intake and discharge duct are 1 foot apart, edge to edge. Do you need to separate the ducts? If so, how many feet?

cooling and heating

What's the load calculation rule of thumb for a restaurant space? For example in a residential building, it's 30 BTU/SF or 1 CFM/SF. The location is in New Jersey.

The project is located in new jersey.

Can you install a 90% Gas Furnace in an unconditioned attic? We are a Mechanical Contractor and plan to install a 90% Gas Furnace in the attic for a Townhouse project. My questions are: 1. Freezing an issue? condensation from the furnace. 2. Would there will be a Gas Furnace performance issue...

thanks guys, appreciate it.

if i go 1-inch slot, it's enough. I need about 30-40 CFM/ft. So, it's better to go 1/2", 2-slot?

I'm trying to select linear diffuser for a lobby area. I have a choice of 1-slot or 2-slot. The linear diffusers are to be located at the perimeter of the space. Do I need to select 2-slot, one for vertical airflow direction, one for horizontal direction? Or 1-slot linear diffuser good enough...

In a VRV multi-zone split systems, how do you calculate the additional refrigerant if required? For instance, the developed refrigerant piping is very long, let's say 300 feet.

If you want to go Air-cooled Chiller and the cooling load is 91 tons. What would happen if you select a 90-ton Chiller? Or you have to go to next size, let's say 100-ton Chiller. That's if you're using just one Chiller for the 90 tons load.

RTU - Roof Top Unit. The Project is located in New Jersey.

We have RTU's with Gas Heat and a significant gas piping to the RTU's are exposed. Do we need to insulate or weatherproof the piping like we need to weatherproof the exposed ductwork?

I think that thermal insulation is used primarily to maintain the supply air temperature and condensation second. Duct Lining is for sound attenutation. I often heard co-workers saying that if the duct is lined, it doesn't need to be insulated because the liner takes care of the condensation. I...

I work for a Mechanical Contractor and we are looking for a Hydraulic Calculation Software for Sprinkler System. Any suggestions? Thanks.

I wanted to know if do you need to be a P.E. to design HVAC or do a load calculation? Or does your work or design needs to be stamped by a P.E.? I work for a Mechanical Contractor but we have no P.E. employee. Thanks.

A Shell and Tube Heat Exchanger with Hot Side EWT 200F and LWT=180F. Another Shell and Tube Heat Exchanger with Hot Side EWT=300F and LWT=200F. Both with the same working pressure (150 psig) and other equipment specifications. The only difference are the EWT and LVT. Why is it that it's the Heat...

Chicopee, can you post upload that worksheet here? I'm scheduled to attend a HAP training in a couple of months but I have no experience using the software although I'm now trying to teach myself how to use the Trace 700 since I have the Demo version. Maybe this said worksheet can enlighten me...