76
VAPOR-LOGIC
®
VERSION 6 INSTALLATION AND OPERATION MANUAL
Table 76-1:
Multitank priority groups application example
Priority
group
Assignment Description Application considerations
0 Trim
• Provides humidification load “throttling,” this unit sees the small changes as demand
changes.
• Generally, this should be one tank, and it should be relatively small.
• Generally, this tank should be an SSR-controlled electric resistive unit.
An SSR-controlled electric resistive
unit will provide the best control.
1 Load
• Carries the bulk of the load; should be the most cost-effective fuel source.
• Only sees large-step changes if a trim tank is used.
GTS is the most cost effective, but
any unit can be used.
2 Peak
• Makes up the demand not met by trim + load.
• Does not run often, because it is needed in only the most demanding situations.
• Because it does not run frequently (making fuel cost less of an issue), this is a good
assignment for a lower-up-front-cost humidifier.
• Run time is a function of load percentage split into the peak category.
Electric resistive are the most cost
effective (any unit can be used).
3 Redundant
• Provides the capability to offset a tank that is offline for any reason.
• This tank will only run when a trim, load, or peak unit is shut down for service or
alarm conditions and the remaining trim, load, and peak tanks cannot meet demand.
• The redundant should be as large as the largest tank in the system.
See Note 1 below.
• If a redundant tank is used, making it the master controller improves system uptime,
since you will not need to bring down the master controller to service it.
• Electric humidifiers are the most
cost-effective up front.
• Size should be the determining
factor.
• Any unit will work.
Notes:
1. If protection is required against multiple tanks being offline at the same time, the redundant tank should be at least as large as the sum of the X
largest tanks where X is the number of tanks for which protection is desired.
2. From a fuel cost standpoint, electric should have the lowest priority. It should run last and the least.
3. From an energy standpoint, GTS generally has the lowest operating cost.
4. When calculating energy, consider heat loss from distribution and piping of steam.
5. Humidifiers within a priority group are load leveled.
6. Humidifiers within a group should have the same energy source.
Multiple-tank operation
OPERATION
To Next Page
Loading...
