No subject


Wed Mar 16 13:13:09 PDT 2011


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AIR-CONDITIONING CREDITS

Specific air conditioning credits vary substantially from case style to case
style. Case loads are made up of internal electric loads, radiant heat from
exterior lighting (very substantial on top display cases), wall conduction
and the infiltration load which is a combination of sensible and latent
heat. Manufacturers also usually add some percentage for safety to account
for loading techniques, traffic, warm product and times of poor ambient
control. It would not be practical to try and exactly calculate the credit
for each style of case and its application. A general rule is acceptable
that takes into account the mix of cases in a typical store since the air
conditioning calculation itself is partly an educated guess particularly
considering outside air influences and person loads.

Only open cases should be considered for this calculation. Walkin coolers
and freezers and glass door merchandisers should not be used. The following
credit is then usually acceptable and should be calculated using the total
published open case load.

	sensible credit = 40%
	latent credit = 30%

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Can someone comment on the disparity between the above numbers and the
respective 65%-10% credits in DOE2.1E?
Also, should it be understood that closed cases should not be considered as
zone loads in a DOE2.1 simulation?
Has anyone had trouble using the REFG-SENS-SCH and REFG-LAT-SCH commands?
The results I get with or without schedules are identical.




Thank you again for your help.




Dominique Michaud
Building Energy Technician
Dessau-Soprin Inc.
375 blvd Rolland-Therrien, Suite 400
Longueuil, Quebec, J4H 4A6
Tel.: (514) 281-1033 ext 2568
Fax: (450) 442-9996


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