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It is an industry trademark name for a
'Low Emissivity Ceiling' system. Aluma-ZorbT has been designed
and engineered for the sole purpose of being installed in ice
rink applications. Ideally suited for both curling and skating
rink facilities, these ceilings have gained a very favorable
reputation as being the number one method of reducing energy
costs in an ice rink. Over the past decade and a half, the results
from this technology have been documented and scrutinized by
many independent groups, including the following:
- Canadian Electrical Association
- A.S.H.R.A.E. (American Society of
Heating, Refrigeration, Air Conditioning Engineers)
- Several State, Provincial and local
utilities
- U.S. Department of Energy
- Many of the above mentioned have previously
provided funding for this technology to help reduce energy
consumption.
It removes radiant heat transfer, thereby
reducing the high costs associated with operating refrigeration
plants.
In an ice rink there are two surfaces which face each other,
the cold ice and the warmer roof. Similar to how the sun heats
the earth's surface, the arena roof warms the ice surface. The
difference in surface temperatures creates a process which is
termed "Radiant Heat Transfer" between the roof and ice surface.
According
to A.S.H.R.A.E., radiant heat transfer accounts for an
average of 28% of the heat load exerted on the ice surface.
If this heat load is removed we know that the refrigeration
compressors will operate less frequently. The Aluma-ZorbT
ceiling works by creating a (radiant) barrier between
the warm roof and the colder ice below.
The aluminum material contained within the panels must
face the ice surface and be free of mechanical contact
with other surfaces to achieve the desired result. Aluminum
is chosen for it's inability to radiate heat (low emissivity).
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Aluma-ZorbT will radiate (allow to pass
through) only 3% of the heat contained in the roof structure
above. By comparison, common building materials used in the
construction of arena roofs will radiate anywhere from 70% to
90% of their heat when located opposite a cooler surface.The
net effect is a substantial reduction in the amount of heat
that is directed to the ice surface and therefore the amount
of work (run hours) required from the refrigeration compressors.
The highly reflective surface of Aluma-ZorbT
can increase light levels from 10-50%.
Insulation is designed to reduce conductive
or convective heat flow, not radiant. Misconceptions about the
appropriate location and R-value of insulation in ice rinks
are quite common. Insulation should always be located in a roof
or wall design on the warm side of the structure. Furthermore
one should avoid the costs associated with "over insulating",
which has become quite common over the past decade. Increasing
the R-value of the roof insulation does not decrease the effects
of radiant heat transfer.
"Failure to acknowledge both of the
above issues can result in the formation of condensation".
Looking at many pre-engineered arenas built over the past thirty
years it has been common practice to suspend the insulation
blanket over the roof purlins and below the decking. This has
created severe moisture problems in these rinks. Why? When comparing
the outdoor temperature to the indoor temperature over the
course of the operating season it is evident that the average
temperature is warmer outside than inside, leaving the insulation
on the cold side of the roof structure. (This has become an
even more critical problem now that many of these rinks are
being pressured to extend their ice season due to increased
demand.) Often the air space in and around the insulation cavity
will drop below dewpoint (temperature at which condensation
forms) succeeding in trapping moisture and creating rust on
the steel roof components. This serves to reduce the life span
of the structure.
It is important to note that a properly
designed Low Emissivity Ceiling contains no R-value.
Installing an Aluma-ZorbT ceiling can dramatically reduce or
eliminate this problem by blocking the heat normally lost through
radiation and using that heat energy to warm and maintain the
roof components above the dewpoint temperature. |
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