Control of air conditioning cooling or heating coil

Abstract

A fluid heat exchanging device, comprising a header and a plurality of interconnecting circuits between an supply port and a return port, the interconnecting circuits being connected to the header by a corresponding plurality of connection ports at different locations along the header wherein the header includes a blocking control element inside the header, the blocking control element being positionally adjustable along the header to selectively block fluid flow from the supply port through the connection ports of the plurality of interconnecting circuits, thereby selectively controlling those interconnecting circuits of the plurality of interconnecting circuits which are subjected to fluid flow therethrough in dependency on the position of the blocking control element.

1 . A fluid heat exchange device comprising: 
 a supply header connected to a supply port;    a return header connected to a return port;    a plurality of interconnecting circuits that are connected to each of the supply header and the return header, the plurality of interconnecting circuits connected to the supply header by a corresponding plurality of connection ports at different locations along the supply header;    a weighted free floating piston located in the supply header, a position of the piston depending on a weight of the piston and a differential pressure, so that the piston is positionally adjustable along the supply header to selectively block fluid flow from the supply port through the connection ports of the plurality of interconnecting circuits, thereby selectively controlling those interconnecting circuits of the plurality of interconnecting circuits that are subjected to fluid flow therethrough based on the position of the piston; and    a control element that selectively controls the differential pressure.    
   
   
       2 . The fluid heat exchange device of  claim 1 , wherein the control element comprises a control valve.  
   
   
       3 . The fluid heat exchange device of  claim 2 , wherein the control valve is disposed at the return port.  
   
   
       4 . The fluid heat exchange device of  claim 2 , wherein the control valve comprises a butterfly valve.  
   
   
       5 . The fluid heat exchange device of  claim 2 , wherein the control valve comprises a motorized valve.  
   
   
       6 . The fluid heat exchange device of  claim 2 , wherein a degree of opening of the valve depends on a difference between a monitored temperature and a setpoint of the fluid heat exchange device.  
   
   
       7 . The fluid heat exchange device of  claim 1 , wherein the control element comprises a second piston disposed at the return port, the second piston controlled by a fluid pressure to restrict fluid flow through the return port.  
   
   
       8 . The fluid heat exchange device of  claim 1 , wherein the control element comprises a pump.  
   
   
       9 . The fluid heat exchange device of  claim 1 , wherein pump is disposed at the supply port, and controls the differential pressure by controlling the fluid flow through the supply port.  
   
   
       10 . The fluid heat exchange device of  claim 1 , further comprising an ultrasonic transducer disposed at one end of the supply header, the ultrasonic transducer measuring the position of the piston.  
   
   
       11 . The fluid heat exchange device of  claim 1 , further comprising: 
 a multi turn potentiometer that measures the position of the piston, the multi turn potentiometer disposed outside of the supply header; and    a threaded rod disposed in the supply header, the threaded rod coupled to the multi turn potentiometer and passing through the piston so that the threaded rod rotates when the piston moves within the supply header, the multi turn potentiometer measuring the position of the piston based on the rotation of the threaded rod.    
   
   
       12 . The fluid heat exchange device of  claim 1 , wherein the piston comprises a permanent magnet, and wherein a magnetic reed switch is disposed at a selected position on a housing of the supply header, the magnetic reed switch being closed when the permanent magnet is in close proximity to the magnetic reed switch, to detect that the piston is positioned near the selected position.  
   
   
       13 . The fluid heat exchange device of  claim 1 , wherein the fluid heat exchange device is configured as a cooling fluid device.  
   
   
       14 . The fluid heat exchange device of  claim 1 , wherein the fluid heat exchange device is configured as a heating fluid device.  
   
   
       15 . The fluid heat exchange device of  claim 1 , wherein a medium cooled or heated by the fluid heat exchange device comprises air.  
   
   
       16 . An air cooling system comprising: 
 a cooling coil and a supply air fan that moves air over the cooling coil, wherein the cooling coil comprises:    a supply header connected to a supply port that supplies a chilled fluid to the cooling coil;    a return header connected to a return port;    a plurality of interconnecting circuits that are connected to each of the supply header and the return header, the plurality of interconnecting circuits connected to the supply header by a corresponding plurality of connection ports at different locations along the supply header;    a weighted free floating piston located in the supply header, a position of the piston depending on a weight of the piston and a differential pressure, so that the piston is positionally adjustable along the supply header to selectively block fluid flow from the supply port through the connection ports of the plurality of interconnecting circuits, thereby selectively controlling those interconnecting circuits of the plurality of interconnecting circuits that are subjected to fluid flow therethrough based on the position of the piston; and    a control element that selectively controls the differential pressure.    
   
   
       17 . A method of controlling a fluid heat exchange device, the method comprising: 
 providing a fluid heat exchange coil that comprises a supply header connected to a supply port, a return header connected to a return port, and a plurality of interconnecting circuits that are connected to each of the supply header and the return header, the plurality of interconnecting circuits connected to the supply header by a corresponding plurality of connection ports at different locations along the supply header;    providing a weighted free floating piston in the supply header, a weight of the piston selected at least in part based on a design pressure drop of the fluid heat exchange coil; and    using a differential pressure to move the piston along the supply header to selectively block fluid flow from the supply port through the connection ports of the plurality of interconnecting circuits, thereby selectively controlling those interconnecting circuits of the plurality of interconnecting circuits that are subjected to fluid flow therethrough based on the position of the piston.    
   
   
       18 . The method of  claim 17 , wherein using a differential pressure to move the piston further comprises using a valve at the return port to selectively control the differential pressure.  
   
   
       19 . The method of  claim 17 , wherein using a differential pressure to move the piston further comprises using a pump at the supply port to selectively control the differential pressure.  
   
   
       20 . The method of  claim 17 , wherein using a differential pressure to move the piston further comprises controlling the differential pressure based at least in part on a difference between a monitored temperature and a setpoint of the fluid heat exchange device.