Controlling humidity in zones during a drying process

Abstract

A method of controlling humidity in each of a plurality of zones of an enclosed space during a drying process includes, in each zone, drawing air from the zone to create an air stream through a heating element and discharging the air stream into the zone; sensing the relative humidity of the air in a sensing location in the zone; in response to the relative humidity sensed at the sensing location, operating the heating element to raise a temperature of the air stream as required to reduce the relative humidity of the air in the zone to a desired relative humidity. The method reduces over-drying and increases the efficiency of the drying process.

1 . A method of controlling humidity in each of a plurality of zones of an enclosed space during a drying process, the method comprising: 
 in each zone, drawing air from the zone to create an air stream through a heating element and discharging the air stream into the zone;    sensing the relative humidity of the air in a sensing location in the zone;    in response to the relative humidity sensed at the sensing location, operating the heating element to raise a temperature of the air stream as required to reduce the relative humidity of the air in the zone to a desired relative humidity.    
   
   
       2 . The method of  claim 1  wherein the sensing location is located to sense the relative humidity of the air stream after the air stream passes through the heating element.  
   
   
       3 . The method of  claim 1  comprising drawing air from the zone to create an air stream through a heating element and discharging the air stream into the zone by providing a portable heat exchanger unit in each zone, each portable heat exchanger unit comprising: 
 a fan operative to create the air stream by drawing air from an intake and discharging the air through an outlet; and    a heating element located in the air stream.    
   
   
       4 . The method of  claim 3  comprising sensing the relative humidity by providing a humidity sensor operative to sense the relative humidity of the air in the sensing location in the zone and operative to send a humidity signal.  
   
   
       5 . The method of  claim 4  comprising mounting the humidity sensor on the portable heat exchanger unit in the zone such that the sensing location is at the outlet of the portable heat exchanger unit to sense the relative humidity of the air stream as it is discharged through the outlet.  
   
   
       6 . The method of  claim 4  comprising providing a heat controller operative to receive the humidity signal and operative to change an amount of heat energy supplied to the heating element in response to the humidity signal.  
   
   
       7 . The method of  claim 6  wherein the heating element comprises a fluid coil connected to a fluid heater such that heated fluid from the fluid heater flows through the fluid coil, and wherein the heat controller is operative to adjust an amount of heated fluid flowing through the fluid coil from a maximum flow to a minimum flow.  
   
   
       8 . The method of  claim 7  wherein the fluid heater is connected to the fluid coil of a portable heat exchanger unit in each zone.  
   
   
       9 . The method of  claim 8  wherein a temperature of the heated fluid at a supply port of the fluid heater increases when the amount of heated fluid flowing through the fluid coils is reduced below the maximum flow.  
   
   
       10 . The method of  claim 9  wherein the fluid heater has a heating capacity that is insufficient to raise the temperature of the air stream in each zone such that the relative humidity of each air stream is reduced to the desired relative humidity, and wherein when the heat controller on a first portable heat exchanger unit reduces the flow of heated fluid below the maximum flow, the temperature of the heated fluid at the supply port of the fluid heater increases.  
   
   
       11 . A method of drying an enclosed space, the method comprising: 
 providing a plurality of portable heat exchanger units, each portable heat exchanger unit comprising: a fan operative to create an air stream by drawing air from an intake and discharging the air through an outlet; a fluid coil located in the air stream; and a heat controller operative to adjust a flow of fluid through the fluid coil;    positioning at least one portable heat exchanger unit as an outside air unit with the intake thereof oriented to draw air from outside the enclosed space and with the outlet thereof oriented to discharge the air stream thereof into the enclosed space;    positioning a plurality of portable heat exchanger units as inside air units at spaced apart unit locations inside the enclosed space and orienting the intakes and outlets of each inside air unit to draw air from the enclosed space adjacent to the inside air unit and to discharge the air stream into the enclosed space adjacent to the inside air unit;    connecting the fluid coils of each portable heat exchanger unit to a fluid heater and circulating heated fluid from the fluid heater through the fluid coils and operating the fans;    sensing the relative humidity of the air stream created by each inside air unit; and    operating the heat controller of each inside air unit to raise a temperature of the corresponding air stream as required to reduce the relative humidity of the air stream to a desired relative humidity, and    allowing an amount of air substantially equal to the amount of air drawn from outside the enclosed space to exhaust from the enclosed space.    
   
   
       12 . The method of  claim 11  comprising dividing the enclosed space into zones and positioning a portable heat exchanger unit in each zone.  
   
   
       13 . The method of  claim 11  comprising sensing the relative humidity of the air stream created by each inside air unit by mounting a humidity sensor on each inside air unit at a sensing location such that the humidity sensor is operative to sense the relative humidity of the air stream, and wherein each heat controller is operative to receive a humidity signal generated by the humidity sensor.  
   
   
       14 . The method of  claim 11  further comprising sensing the relative humidity of the air stream of the outside air unit and operating the heat controller of the outside air unit to raise a temperature of the corresponding air stream as required to reduce the relative humidity of the air stream to a selected relative humidity.