really high cfm in small office room

[swoosh172]

So I have a building, built in 1940 with 8 inch concrete walls and no insulation that is being converted to an office building. I have run the load calc using trace 700 and the cfm has come out with 11,000cfm for 7,000 sf of space, summer design is 93F. The walls are 75% windows double pane with an estimated U value of 0.6. I'm concerned in some small 1 person office rooms where the load is having me dump close to 800 cfm into a 240SF room with two 12 ft long exterior walls each wall with a 10x6 window. I have each room on a vav w/hw reheat box, but I don't want complaints of drafts, which may be inevitable with the characteristics of this building. I do know that they do not have AC in the building now and they have to close the second floor because it gets too hot in the summer. Should I follow the program, or lower the cfm's some?

 

[MintJulep]

Maybe point out to the client that some insulation would have an attractive payback.

 

[AbbyNormal]

blinds would be more effective than insulation

The way we build has a far greater impact on our comfort, energy consumption and IAQ, than any HVAC system we install

 

[ChasBean1]

Interior window dressings don’t have much of an effect. I think you don’t want to change your vav design and cfm/ft2 but rather have a broad range via vav operation. Design for values that you mention. Use a good turn-down ratio for each vav zone…

 

[ChasBean1]

Interior window dressings don’t have much of an effect. I think you don’t want to change your VAV design and cfm/ft2 but rather have a good turn-down. Design for values that you mention. Use VFDs and vav devices in those areas…

 

[ChasBean1]

Hmmm, maybe I should've posted that again.

 

[mauricestoker]

If you have space above the ceiling, you might consider linear diffusers above the windows.

 

[walkes]

Change the glazing? Provide external shading with a nice architectural feature?

I have used linear diffusers above the windows with a heat/cool changeover, where they blow down the window in heating mode and into the room at high level for induction in cooling mode.

http://www.price-hvac.com/catalog/B_all/SectionB.aspx?pageRequest=TBDI6_1

 

[RossABQ]

I'm curious where this is, that they would let you make such a dramatic change in use and not make any real effort to conform to something approaching energy efficient envelope? 3" of styrofoam applied to the exterior, with stucco overcoat, would have dramatic results. What are your heating air flows? I would expect equally dramatic flow rates.

 

[AbbyNormal]

Insualting that concrete is effective in heating mode.

If the building was in Miami, 90.1 would not even call for insulation on walls with thermal mass.

The way we build has a far greater impact on our comfort, energy consumption and IAQ, than any HVAC system we install

 

[mauricestoker]

A perimeter heating/cooling system may take off quite a bit of loading, especially if there is a problem with other perimeter zones. VRF's are used quite often for historic preservation requirements where the window cannot be changed or readily upgraded.