Fresh air ventilation control system

Abstract

This disclosure relates to a fresh air ventilation (FAV) controller. The FAV controller may include multiple input devices for setting a target fresh air ventilation flow rate (FAVFR), an operating FAVFR for an air handler, an operating FAVFR of a first ventilation appliance, an operating FAVFR of a second ventilation appliance. The FAV controller further includes electric interfaces adapted to couple to the air handler and a thermostat for controlling the air handler, a sensor for monitoring an operation of the first ventilation appliance, the second ventilation appliance, a thermometer for monitoring temperature of fresh air in a ventilation path to the air handler, and a motorized damper disposed in the fresh air ventilation path. The FAV controller may be configured to monitor operation times of the air handler, the first ventilation appliance, the second ventilation appliance, and the thermometer via the electric interfaces, and to control the air handler and the motorized damper, and/or the second ventilation appliance via the electric interfaces.

What is claimed is: 
     
         1 . A fresh air ventilation control (FAVC) system comprising:
 a first input device for setting a first fresh air ventilation flow rate (FAVFR) as a target for a continuous fresh air ventilation;   a second input device for setting a second FAVFR of an air handler when in operation;   a third input device for setting a third FAVFR of a first ventilation appliance when in operation;   a first electric interface adapted to couple to the air handler and a thermostat for controlling the air handler;   a second electric interface adapted to couple to a sensor for monitoring an operation of the first ventilation appliance;   a system circuitry configured to, in a consecutive first cycle and second cycle of multiple control cycles:
 monitor an effective FAVFR of the first ventilation appliance during the first cycle based the third FAVFR and an operation time of the first ventilation appliance during the first cycle measured via the second electric interface; 
 monitor, via the first electric interface, an effective FAVFR of the air handler during the second cycle based on the second FAVFR and an operation time of the air handler during the second cycle under the control of the thermostat; and 
 generate a control signal for obtaining supplemental fresh air ventilation during the second cycle when a sum of the effective FAVFR of the ventilation appliance and the effective FAVFR of the air handler is less than the first FAVFR. 
   
     
     
         2 . The FAVC system of  claim 1 , further comprising:
 a fourth input device for setting a fourth FAVFR of a second ventilation appliance when in operation;   a third electric interface adapted to couple to the second ventilation appliance; and   a mode selector for setting the FAVC system to one of a normal mode and an energy-saving mode,   wherein the control signal is sent to the second ventilation appliance via the third electric interface for obtaining the supplemental fresh air ventilation and is prevented from being sent to the air handler when the mode selector is set to the energy-saving mode, and is sent to both the second ventilation appliance and the air handler for obtaining the supplemental fresh air ventilation when the mode selector is set to the normal mode.   
     
     
         3 . The FAVC system of  claim 2 , wherein a duration of the control signal is determined by:
 a difference between the first FAVFR and the sum of the effective FAVFR of the ventilation appliance and the effective FAVFR of the air handler; and   the fourth FAVFR when the mode selector is set to the energy-saving mode or a sum of the second FAVFR and the fourth FAVFR when the mode selector is set to the normal mode.   
     
     
         4 . The FAVC system of  claim 1 , further comprising a fourth electric interface adapted to couple to a motorized damper disposed in a fresh air ventilation path coupled to a return path of the air handler, wherein the system circuitry is further configured to keep the motorized damper open during the supplemental fresh air ventilation. 
     
     
         5 . The FAVC system of  claim 4 , further comprising:
 a third electric interface adapted to couple to a second ventilation appliance,   wherein the system circuitry is further configured to monitor the second ventilation appliance via the third electric interface and keep the motorized damper open when the second ventilation appliance is in operation.   
     
     
         6 . The FAVC system of  claim 1 , further comprising a fourth electric interface adapted to couple to a thermometer for monitoring temperature of fresh air in a ventilation path coupled to a return path of the air handler, wherein a duration of the control signal for obtaining supplemental fresh air ventilation is dependent on the monitored temperature. 
     
     
         7 . The FAVC system of  claim 6 , wherein the duration of the control signal is reduced to zero when the monitored temperature is lower than a first predetermined temperature threshold or higher than a second predetermined temperature threshold. 
     
     
         8 . The FAVC system of  claim 1 , further comprising:
 a fourth electric interface adapted to couple to a thermometer for monitoring temperature of fresh air in a ventilation path coupled to a return path of the air handler; and   a humidity sensor for monitoring relatively humidity of a return air of the air handler,   wherein a duration of the control signal for obtaining supplemental fresh air ventilation is dependent on the monitored temperature and relative humidity.   
     
     
         9 . The FAVC system of  claim 8 , wherein the duration of the control signal is reduced by a predetermined proportion for a predetermined set of ranges for the monitored temperature and relative humidity. 
     
     
         10 . The FAVC system of  claim 1 :
 wherein the thermostat controls the air handler to operate in one of a cooling and a heating mode;   wherein the second input device comprises a first input component and a second input component for independently setting a cooling FAVFR of the air handler when operating in the cooling mode and a heating FAVFR of the air handler when operating in the heating mode;   wherein the system circuitry is further configured to monitor an operating mode of the air handler via the first electric interface; and   wherein the second FAVFR comprises one of the cooling FAVFR and the heating FAVFR in correspondence with the monitored operating mode of the air handler.   
     
     
         11 . A fresh air ventilation control (FAVC) system, comprising:
 a first input device for setting a first fresh air ventilation flow rate (FAVFR) as a target for a continuous fresh air ventilation;   a second input device for setting a second FAVFR of an air handler when in operation;   a third input device for setting a third FAVFR of a first ventilation appliance when in operation;   a fourth input device for setting a fourth FAVFR of a second ventilation appliance when in operation;   a first electric interface adapted to couple to the air handler and a thermostat for controlling the air handler;   a second electric interface adapted to couple to a sensor for monitoring an operation of the first ventilation appliance;   a third electric interface adapted to couple to the second ventilation appliance;   a fourth electric interface adapted to couple to a thermometer for monitoring temperature of fresh air in a fresh air ventilation path coupled to a return path of the air handler;   a fifth electric interface adapted to couple to a motorized damper disposed in the fresh air ventilation path; and   a system circuitry configured to:
 monitor operation times of the air handler, the first ventilation appliance, the second ventilation appliance, and a measurement of the thermometer via the first, the second, the third, and the fourth electric interfaces; and 
 control the motorized damper, and/or the air handler, and/or the second ventilation appliance via the first, the third, and the fifth electric interfaces. 
   
     
     
         12 . The FAVC system of  claim 11 , wherein the system circuitry is further configured to keep the motorized damper open and keep a central fan of the air handler on when the second ventilation appliance is in operation. 
     
     
         13 . The FAVC system of  claim 11 , wherein the system circuity, when configured to control the air handler and the motorized damper and/or the second ventilation appliance, is configured to control air handler and the motorized damper and/or the second ventilation appliance in periodic ventilation cycles. 
     
     
         14 . The FAVC system of  claim 13 , wherein the system circuitry is configured to control the air handler and the motorized damper and/or the second ventilation appliance to meet a predetermined ventilation target in a ventilation cycle. 
     
     
         15 . The FAVC system of  claim 14 , wherein the system circuitry is configured to credit the monitored operation time of the first ventilation appliance in a first ventilation cycle to the predetermined ventilation target of a second ventilation cycle following the first ventilation cycle. 
     
     
         16 . The FAVC system of  claim 11 , further comprising a mode selector for setting the FAVC system into either a normal control mode or an energy saving control mode. 
     
     
         17 . The FAVC system of  claim 16 , wherein, when the FAVC system is set in the energy saving mode, the FAVC system is configured to control the motorized damper and/or the second ventilation appliance and is configured to leave a control of the air handler to the thermostat unless the air handler is idle for a predetermined idle time. 
     
     
         18 . The FAVC system of  claim 16 , wherein, when the FAVC system is set in the normal mode, the FAVC system is configured to control the motorized damper and the second ventilation appliance, and is further configured to control the air handler in conjunction with the thermostat. 
     
     
         19 . The FAVC system of  claim 11 , further comprising a humidity sensor for monitoring a relative humidity of air in the return path of the air handler, wherein a set of constraints based on the monitored relative humidity and the measurement of the thermometer is applied when the FAVC system is configured to control the motorized damper, and/or the air handler, and/or the second ventilation appliance. 
     
     
         20 . The FAVC system of  claim 11 , wherein the system circuitry is further configured to disable control over the motorized damper, the air handler, and the second ventilation appliance when the measurement of the thermometer is above a predefined high temperature threshold or below a predefined low temperature threshold.