I expect the project is coastal Maine since Lassel Architects is in Maine.
The weather probably does not turn on a dime, which simplifies the choices.
The recommendation for radiant floors is good since they can be done in 2" which is the not muich impact on the floor to floor height and is popular in Maine. Unfortunately it also means a new door in every opening. The same applies to the recommendation for raised floor serving as a heating plenum, which is a more flexible system but requires 6" depth.
The other potential problem is height movement down through the radiant floor ceilng surface. Fortunately, ceiling insultaion is a necessity for both acoustic and thermal reasons.
If you use a radiant floor, place a bubble wrap insulation on the slab for sepatation plus a slippage sheet under any ceramic tile. Do not use VCT or sheet vinyl. Place insulation in the ceiling cavity also.
Is the building able to function on natural ventilation only?
You might consider just baseboard heating for no impact on the floor to floor height.
If cooling is required, simply circulating cold domestic or heat pump cooled water in the slab could work since the building could be set up to require a winter to summer change over.
If more flexibility is required, two piping systems could be run so that a unit could be cooled or heated without a building change over. PEX tubing is cheap, it is the topping slab which is expensive for radiant systems.
Or you could use a Packaged terminal unit system as suggested by the architect from California.
When you choose a mechanical engineer ask if he is familiar with any or all of the systems discussed on the forum.
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Rex Peterson AIA
Baker & Associates
Scottsbluff NE
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Original Message:
Sent: 02-15-2012 07:51
From: Francois Levy
Subject: mechanical systems for mid rise
The problem that Michael is facing is that even if the project is heated with a radiant floor system, and ceilings are outfitted with radiant cooling panels (problematic for humid climes due to condensation concerns), that still doesn't address ASHRAE fresh air standards.
Michael, my suggestion is procedural, not technological. I would recommend you consider some form of IDP and bring in a mechanical engineer into the team at the earliest phases of conceptual design.
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Francois Levy, AIA, AIAA
M.Arch, MSE
Author, BIM in Small-Scale Sustainable Design
http://is.gd/UJPFta
http://www.francoislevy.com
Twitter: @Francois_Levy
702 San Antonio Street
Austin, TX 78701
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