Intelligent coolant flow control system

A coolant distribution system and method for a plurality of devices requiring cooling where the coolant source is of limited capacity. The system and method apportion coolant to each of the devices requiring cooling based upon instantaneous knowledge of the waste heat load of the devices. This is accomplished by providing a scheduler, which is preferably a computer having a data base, to concurrently determine the instantaneous amount of coolant apportioned for each of the devices. In response to this determination the flow of coolant from the coolant source to the devices is controlled in accordance with the apportioned flow of coolant for each device based upon a predetermined schedule. The coolant flow rate is controlled by providing a controllable valve coupled to the coolant source, determining the flow rate of coolant through the valve and a flow controller responsive to the scheduler and the determination of the flow rate of coolant through said controllable valve to control the controllable valve.

This application claims the benefit of U.S. Provisional application No. 
60/015,111, filed on Apr. 10, 1996, abandoned. 
BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a coolant distribution system and method for a 
plurality of devices requiring cooling where the coolant source is of 
limited capacity. 
2. Brief Description of the Prior Art 
A significant problem arises in systems, such as, for example, phased array 
systems, wherein there is a requirement for removal of waste heat from 
multiple phased arrays that share a single source of coolant. This is 
complicated by the fact that systems using multiple arrays can have 
several different types of phased arrays used in unpredictable 
combinations. Also, similar arrays can be operated in different modes 
along with dissimilar arrays also in different modes among themselves. The 
problem is to control the available coolant to remove waste heat while 
providing conditions that promote maximum system coolant use efficiency 
and maximum system level reliability. This problem is increasingly 
apparent where the amount of available coolant is limited and may be 
insufficient to provide the required cooling if not efficiently used or 
which may be insufficient even if efficiently used and must be judiciously 
apportioned to maximize system reliability under these conditions. 
Prior art cooling systems have generally operated selectively on an all on 
or all off basis, or have provided the coolant to all devices in the 
system on a continuous basis, regardless of cooling requirements and the 
amount of waste heat generated by each device as a function of time. 
SUMMARY OF THE INVENTION 
In accordance with the present invention, there is provided a system for 
making maximum utilization of a coolant flow when multiple phased arrays 
are cooled from a common coolant source. 
The invention allows for the optimization of coolant flow rate to those 
arrays producing more waste heat while comprehending the flow requirements 
for the arrays producing lesser waste heat. Doing so for all allowable 
combinations of array simultaneous operation insures each array is 
operating with the lowest possible failure rate levels. With an increased 
coolant flow rate, there is increased efficiency of waste heat removal 
from array subassemblies. This results in decreased component 
temperatures. With decreased component temperatures, lower component 
failure rates result. By intelligently controlling the flow of coolant 
reactive to array usage, active systems are operated in a mode where the 
component temperatures are at the lowest possible for the overall level of 
system usage and system performance at that time. The intelligent 
controller adjusts the coolant flow rate reactive to any state of array 
usage. With this form of control, the system runs with the lowest possible 
component failure rates possible based upon the overall level of system 
usage. 
Briefly, there is provided a coolant distribution system and method for a 
plurality of devices requiring cooling where the coolant source is of 
limited capacity. The system and method apportion coolant to each of the 
devices requiring cooling based upon instantaneous coolant requirement. 
This is accomplished by providing a scheduler, which is preferably a 
computer having a data base, to concurrently determine the instantaneous 
amount of coolant that can be apportioned to each of the devices. In 
response to this determination the flow of coolant from the coolant source 
to the devices is controlled in accordance with the total cooling 
available and the apportioned amount for each device. The coolant flow 
rate is controlled by providing a controllable valve coupled to the 
coolant source, determining the flow rate of coolant through the valve and 
a flow controller responsive to the scheduler and the determination of the 
flow rate of coolant through said controllable valve to control the 
controllable valve.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIG. 1, there is shown the architecture in accordance with the 
present invention when used in a jammer pod that has eight phased arrays. 
In the example shown, four of the phased arrays are high band arrays and 
four arrays are midband arrays, it being understood that the array being 
cooled are merely exemplary and can be replaced by other types of arrays 
or any other type of device requiring cooling on a continual or 
intermittent basis. The eight arrays are required to be operational 
simultaneously within prime power limits and in combinations below prime 
power limits. Whereas the prior art systems generally apply a constant 
flow of coolant of constant amount to all of the arrays, regardless of 
heat requirements at any point in time, the intelligent coolant flow 
control system partitions coolant flow for each array based upon 
requirement at that time on a "pound mass per minute per KW" basis for all 
allowable combinations of simultaneous operation, both at and below prime 
power limits. During periods of operation, when all arrays are not fully 
active or not active at all, increased coolant flow is provided to those 
arrays that are fully or partially active, this being accomplished by 
partitioning the flow of coolant to the array in proportion to the amount 
of waste heat each active array produces at that time. Simultaneously, 
coolant flow rate can be decreased or even stopped to those array which 
are then inactive. 
FIG. 1 describes a coolant distribution generally which depicts both the 
prior art as well as the present invention when the structure of FIG. 2 is 
added thereto as explained hereinbelow. In the prior art, coolant is 
cooled by the on board Environmental Control Unit (ECU) and pumped to the 
coolant manifold. The coolant is then directed continually at a 
predetermined level to each of the arrays shown as high band (HB) Array #1 
to HB Array #4 and medium band (MB) Array #1 to MB Array #4 to cool these 
arrays with the heated coolant then being returned to the coolant manifold 
and then back to the on board ECU for cooling and recycling. The only 
control is for the flows to either be "on" or "off" using valves. The 
problem with the prior art system as described is that a constant flow of 
coolant of constant volume is sent to each array from the coolant 
distribution system without regard to the amount of heat produced at that 
time by each array, this often leaving an insufficient amount of coolant 
for other arrays that have higher levels of waste heat. 
As shown in FIG. 2, this problem is remedied by providing an intelligent 
coolant flow control at the coolant distribution system, one such FIG. 2 
system being provided for each of the eight arrays shown in FIG. 1. The on 
board ECU system is the same as in FIG. 1 and performs the same function 
of cooling received heated coolant and returning the coolant to the 
system. The fluid manifold is common to all of the arrays and makes the 
coolant available to the servovalves for each of the eight arrays shown. 
However, the amount of coolant permitted to pass through the servovalve is 
controlled by a flow controller which, in turn, is responsive to a flow 
rate transducer which measures the coolant flow rate to the particular one 
of the eight arrays being cooled by the intelligent flow control system 
and an array scheduler which determines the amount of coolant required by 
that array and provides a flow demand signal to the flow controller for 
that array in view thereof. The heated coolant is returned to the fluid 
manifold from the array and then from the manifold to the on board ECU for 
cooling and return to the system. The servovalve can be any standard valve 
wherein the fluid flow therethrough can be controlled and the flow 
controller is any standard device which can control the servovalve in 
response to some command thereto. 
The array scheduler is a computer based system that controls the arrays to 
achieve the required tactical functionality. It also apportions the 
available coolant flow to each individual array in proportion to the 
amount of waste heat produced by the individual array relative to the 
total waste heat produced by all active arrays. In most pod mounted jammer 
applications, it is expected that the arrays will be operating at 
different duty cycles and thus will produce different levels of waste 
heat. Accordingly, the array scheduler determines the apportioned flow to 
each array and provides a signal to each individual flow controller 
channel to open the servovalve sufficient to provide the proportioned 
amount of coolant flow. In cases where the total waste heat produced is 
less than the ECU capacity, the coolant is still apportioned by the same 
proportion with the resultant being increased flow made available to each 
active array. This results in cooler operation and enhance reliability. 
Normal operation would limit array total waste heat to the heat removal 
capacity of the ECU. In this mode, maximum array utilization is realized 
with flow directed to the individual arrays based upon array usage at that 
exact instant of time. As individual array usage changes with time, so 
does the apportioned flow to each individual array. 
In the case where, due to a tactical necessity, the arrays are required to 
run for a limited time where the total array waste heat exceeds the ECU 
heat removal capacity, coolant fluid is still apportioned in the same 
manner. This insures that, under short term overload conditions, the 
available cooling capacity, although inadequate, is distributed in such a 
way that thermal damage and reliability degradation are minimized. 
Though the invention has been described with respect to a specific 
preferred embodiment thereof, many variations and modifications will 
immediately become apparent to those skilled in the art. It is therefore 
the intention that the appended claims be interpreted as broadly as 
possible in view of the prior art to include all such variations and 
modifications.