The graphs also indicate that to reach the valuable target of about 200 Nm/l, the pfp and [p.sub.boost] should be above 130 bar and 170 kPaG, respectively.
Figure 15 also shows that for the highest [p.sub.boost] level (190 kPaG), the pfp target of 120 bar cannot be matched, since the minimum possible pfp level is about 125 bar.
The diagrams are relative to the test conditions at 170 kPaG of [p.sub.boost] and with two combinations of [p.sub.rail] and pfp (1500 bar [p.sub.rail], 120 bar pfp) and (2000 bar [p.sub.rail], 140 bar pfp) corresponding to the points reported in Figure 15 (b).
When the header pressure is increased from 3281 kPag to 3548 kPag at 3100th second, the flow reduces to 5049 m3/hr, ASC generates output to open ASV to increase flow to the set point 5500 m3/hr as shown in Fig.16.
Limitations of PID Control Action As the header pressure is increased from 3282 kPag to 3600 kPag at 5860th second in a quick manner to bring quick sever surge, ASC generates 25% output) to open ASV to restore flow but the flow reduces from 6235 m3/hr to 3299 m3/hr and the compressor goes into surge as shown in Fig.
The compressor experiences surge Advanced PI Plus RTL Controller When the header pressure is increased from 3284 kPag to 3619 kPag at 4920th second in a quick manner to bring sever surge, ASC generates 27% output (17% PI + 10% RTL )in a speedy manner to open ASV to restore flow and the flow reduces from 6250 m3/hr to 5213 m3/hr, then restores to 5500 m3/hr as shown in Fig.
As the suction pressure is decreased from 1827 kPag to 1686 kPag at 9140 second, the flow reduces from 6279 m3/hr to 5406 m3/hr, ASC generates 7% output to open ASV to restore flow to the set point 5500 m3/hr as shown in Fig.
The valve operates using PI control to accurately maintain the minimum condensing pressure setpoint of 517 kPag
* The pressure was well below the boiler and piping system component limits-all were rated for over 150 psig at 200[degrees]F (1034 kPag at 93[degrees]C)-so while the pressure was higher than the operator was used to, it was not excessive.
* These codes include a table that includes a column for "pressurized diaphragm type" tanks, correctly sized but limited to systems with 195[degrees]F (91 [degrees]C) average operating temperature, 12 psig (83 kPag) precharge pressure and 30 psig (200 kPag) maximum pressure.
Tanks are factory charged to a standard precharge of 12 psig (83 kPag).[section] For higher desired precharge pressures, either a special order can be made from the factory or the contractor must increase the pressure with compressed air or a hand pump.
([section]) The 12 psig (83 kPag) standard precharge comes from old residential construction where the boiler and expansion tank are typically in the basement.