103 January : February 2014 — CommerCial ConstruCtion & renovation
»CCRS 2014 SpOnSOR • CirCle No. 42
When the mercury drops, the heat load
is daunting – even though the buildings
are well insulated. Winter 2011-2012 saw
ambient temperatures dip as low as -30
degree, with severe winds and record snow-
fall. Most elements of the hydronic heating
system are designed for a 40 degree F
delta-T to lower the fow and conserve
pumping energy.
"The large delta T is also needed for
optimum effciency from the condensing
boilers," McNeal says. "In addition to the
high initial delta-T, the return heating
water is cascaded through in-foor radiant
systems, as well as snowmelt piping in
order to lower it even further to enhance the
condensing at the boilers."
To heat the concrete structures, several
delivery methods are used. Haakon con-
stant-volume hydronic air handlers heat the
cell blocks. To knock out the perimeter chill
in the cells situated against exterior walls,
there's a 6-foot swath of radiant tubing in
" Our job was to 'Alaskanize' the system.
It took a better building envelope and
more robust mechanical system than
what had originally been envisioned."
– Bill McNeal, PE, Principal Mechanical engineer, Coffman Engineers
CCR-JanFeb.14_XX-CVR4.indd 103 2/7/14 1:57 PM