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Hi All, As you may know the EU is looking to reduce the use of HCF gases. This includes common refrigerants such as R-410a. The multi-split VRV/VRF industry heavily uses R-410a. How do you think the new rules will affect the selection of VRV/VRF for new mechanical systems? From my research, the...

Hi John_187, I came to a similar conclusion when working on one of my projects. I found that a unit's sensible heat ratio is completely dependent on air inlet conditions. Several of the big manufacturer's of RTU's such as Carrier and Trane publish charts of the unit's sensible and latent...

Junior engineer here, so take my post with a grain of salt, I'm learning as I go along. I had to do a design study for planning purposes for a similar building minus the laundry room. The big problem we dealt with was the humidity condensing after a shower. At a similar building that is being...

Thanks all for the clear answers. If I understand things right, turning a chiller into a heat pump is possible and some people do it, but it will not necessarily save me any money.

Thanks for the prompt reply! I think I might have miss written my post. I did not mean that the chiller would heat the hot water for sinks and the kitchen but rather it would heat hot water to run through the air handling units to heat the building. This would turn a two pipe cooling only...

One potential issue I see is energy code compliance. Where I work if you heat or cool a building, it must meet code. In my location, the walls need to have R-13 between the studs AND R-10 continuous insulation on the wall. Of course this may differ based on your location, but I thought I would...

Hi all, I am a new junior engineer and have a question about air cooled chillers and heat pumps. Basically, why don't manufactures offer air cooled chillers that can heat the building water as well as chill it for air conditioning purposes? From what I know about heat pumps is that they are...

Thanks all for the replies. The design flow rate of the duct work is around 1000 fpm. Because it is mostly existing duct work, I simply need to check that the total return pressure loss is not too high. With this system the design pressure drop is around 0.15 in. w.g. As for what the ASHRAE C...

Hello all, first time poster here. I have a HVAC pressure loss problem and I am stuck. Here is the background info. I am working on an HVAC renovation project for a commercial office and we are redoing a portion of the return duct work. I am calculating the pressure drop in the return line to...