ASHRAE Research Project 1480 Report - Food Service Technology ...

Evaluation of Appliance Duty with respect to Makeup Air Configuration
Sensitivity of appliance duty was evaluated with one of two appliance line configurations: the
heavy-duty (three broiler) line, or the combination-duty (fryer, broiler, oven) line. These
comparisons were made with three makeup air strategies available, displacement, 4-way ceiling
diffuser, and 4-sided perforated plenum supply. The results are shown graphically in Figure 29.
10000
> 9000 > 9000
8600
Exhaust Airflow Rate [cfm]
8000
6000
4000
4900
5600
7400
7600
7800
2000
0
Combo(F,B,O)
Displacement
Front & Back
102
Combo(F,B,O)
PPS
4 Side
80 cfm/ft
of PPS
119
Heavy(3Broilers)
Displacement
Front & Back
101
Heavy(3Broilers)
PPS
4 Side
80 cfm/ft
of PPS
123
Heavy(3Broilers)
4-Way Diffuser
Front & Side
2000 cfm
(1000 cfm each)
114
Heavy(3Broilers)
PPS
4 Side
160 cfm/ft
of PPS
122
Combo(F,B,O)
PPS
4 Side
160 cfm/ft
of PPS
118
Combo(F,B,O)
4-Way Diffuser
Front & Side
2000 cfm
(1000 cfm each)
110
Figure 29. Evaluation of Appliance Line Duty and Makeup Air Configuration
With displacement ventilation, the combination-duty appliance line required 4,900 cfm (490
cfm/ft) and the heavy-duty appliance line required 7,400 cfm (740 cfm/ft). With displacement
ventilation, the heavy-duty line required a 2,500 cfm (250 cfm/ft) increase from the combinationduty
appliance line’s exhaust rate.
With the front and right side 4-way ceiling diffusers each supplying 1,000 cfm for a total of
2,000 cfm of locally supplied makeup air, the combination-duty appliance line required over
9,000 cfm (900 cfm/ft) and the heavy-duty appliance line required 7,800 cfm (780 cfm/ft). With
this local makeup air configuration, the heavy-duty line required at least 1,200 cfm (120 cfm/ft)
less than the combination-duty appliance line’s exhaust rate. The 4-way diffusers created
turbulence around the hood, which had a great impact on the combination-duty line’s required
3-5
RP-1480