Ventilation Controller

Abstract

A ventilation system for a building in some cases includes a main HVAC blower for moving temperature-conditioned air through the building plus a smaller ventilation blower for providing fresh air. A controller regulates the ventilation blower's speed to provide a target ventilation flow rate regardless of changes in the pressure differential between the indoor and outdoor air. To ensure that the target rate is appropriate for a particular building, the target flow rate is determined based on a ventilation setting that reflects a specified number of bedrooms and a specified amount of floor space of the building.

What is claimed is: 
     
         1 . A ventilation system, comprising:
 a ventilation blower; and   a control system comprising:
 a manual input for entering a ventilation setting; and 
 a controller operatively coupled to the ventilation blower. 
   
     
     
         2 . The ventilation system of  claim 1 , wherein the ventilation setting is communicated to the controller via a setup signal. 
     
     
         3 . The ventilation system of  claim 2 , wherein the ventilation setting and corresponding setup signal reflect a number of rooms and a specified amount of floor space of a structure. 
     
     
         4 . The ventilation system of  claim 1 , wherein the controller provides a command signal to deliver appropriate electrical power for the ventilation blower to provide a desired target ventilation flow rate. 
     
     
         5 . The ventilation system of  claim 1 , wherein the control system regulates a rotational speed of the ventilation blower. 
     
     
         6 . The ventilation system of  claim 1 , wherein the control system cycles the ventilation blower on and off to achieve the target ventilation flow rate as averaged over a predetermined period. 
     
     
         7 . The ventilation system of  claim 1 , wherein a first ventilation supply path between the ventilation blower and the indoor area is independent from a main HVAC system supply path, and wherein a second ventilation supply path between the outdoor area and the ventilation blower is independent from a main HVAC system return path. 
     
     
         8 . The ventilation system of  claim 1 , wherein the control system is configured to determine the actual ventilation flow rate through the ventilation blower as a function of the rotational speed of the ventilation blower and the power consumption of the motor. 
     
     
         9 . The ventilation system of  claim 1 , wherein the control system is configured to selectively regulate a rotational speed of the ventilation blower over a range of rotational speed values, the range including a rotational speed value of zero and a plurality of positive rotational speed values, in response to a change in the determined actual flow rate. 
     
     
         10 . The ventilation system of  claim 1 , wherein the manual input includes at least one of a touchpad, an electrical switch, and a dial. 
     
     
         11 . A ventilation system, comprising:
 a ventilation blower; and   a control system comprising a controller operatively coupled to the ventilation blower, wherein the controller is configured to provide a command signal to a drive unit associated with the ventilation blower to deliver appropriate electrical power for the ventilation blower to provide a desired target ventilation flow rate.   
     
     
         12 . The ventilation system of  claim 11 , wherein the controller includes an input for receiving a setup signal that is based on at least one of the specified number of rooms and the specified amount of floor space, and wherein the target ventilation flow rate is based on the specified number of rooms and the specified amount of floor space. 
     
     
         13 . The ventilation system of  claim 11 , wherein the target ventilation flow rate is based on a certain occupancy level of the building. 
     
     
         14 . The ventilation system of  claim 11 , wherein the control system regulates a rotational speed of the ventilation blower to provide an average target ventilation airflow rate over a predetermined period of time. 
     
     
         15 . The ventilation system of  claim 11 , wherein the control system selectively operates the ventilation blower at a normal mode and an alternate mode such that the average target airflow rate occurs during the normal mode, and an alternate airflow rate occurs during the alternate mode, wherein the alternate airflow rate is distinguishable from the average target airflow rate. 
     
     
         16 . The ventilation system of  claim 15 , wherein the alternate airflow rate is greater than the average target airflow rate. 
     
     
         17 . The ventilation system of  claim 15 , wherein the alternate airflow rate is less than the average target airflow rate. 
     
     
         18 . The ventilation system of  claim 15 , wherein the alternate airflow rate is substantially equal to zero. 
     
     
         19 . The ventilation system of  claim 11 , further comprising:
 an alarm signal for indicating when the ventilation blower may be failing to achieve the target ventilation flow rate.   
     
     
         20 . The ventilation system of  claim 19 , wherein the alarm signal is triggered by a rotational speed of the ventilation blower reaching a predetermined threshold.