HVAC control system and method

Abstract

An HVAC control system configured to control the environment of a building zone includes a means for determining a number of people occupying the building zone and a means for determining properties of other heat transferring objects located within the building zone. The HVAC control system may also include a controller, the controller being configured to compute a projected heat gain in a building zone based on the determined number of people occupying the building zone and the determined properties of the other heat transferring objects located within the building zone. The controller may use the computed projected heat gain to determine a zone ventilation setpoint for the building zone.

1 . An HVAC control system configured to control the environment of a building zone, comprising:
 means for determining a number of people occupying the building zone;   means for determining properties of other heat transferring objects located within the building zone; and   a controller, the controller being configured to compute a projected heat gain in a building zone based on the determined number of people occupying the building zone and the determined properties of the other heat transferring objects located within the building zone;   wherein the controller uses the computed projected heat gain to determine a zone ventilation setpoint for the building zone.   
   
   
       2 . The system of  claim 1 , wherein the zone ventilation setpoint is a volumetric flow rate of air, and wherein the zone ventilation setpoint is used to adjust at least one zone ventilation device capable of affecting the volumetric flow rate of air provided to a building zone. 
   
   
       3 . The system of  claim 1 , wherein the controller includes a feedforward control having inputs of the determined number of people and the determined properties of other heat transferring objects. 
   
   
       4 . The system of  claim 1 , wherein the projected heat gain is a projected convective heat gain to the building zone. 
   
   
       5 . The system of  claim 1 , wherein the means for determining the number of people occupying the building zone includes a radio frequency receiver. 
   
   
       6 . The system of  claim 1 , wherein the means for determining properties of other heat transferring objects located within the building zone includes a wireless sensor. 
   
   
       7 . The system of  claim 1 , wherein the other heat transferring objects of the building zone include heat transferring lights of the building zone. 
   
   
       8 . The system of  claim 7 , wherein the means for determining properties of other heat transferring objects located within the building zone includes a circuit configured to determine a lighting property of the zone. 
   
   
       9 . The system of  claim 1 , wherein the controller is further configured to learn the heating characteristics of the zone; and wherein the HVAC control system uses the learned heating characteristics of the zone and the determined number of people to compute the projected heat gain to the zone based on people and objects. 
   
   
       10 . The system of  claim 1 , wherein the controller is configured to compute the projected heat gains of a zone based on determined properties of people, computers, and lights of the zone. 
   
   
       11 . The system of  claim 1 , wherein the controller is configured to identify at least one person within the zone, and wherein the controller determines a preferred temperature for the identified at least one person within the zone. 
   
   
       12 . The system of  claim 11 , wherein the controller is further configured to identify at least two people located within the building zone in order to determine the zone ventilation setpoint for the building zone using the preferred temperature of the at least two people. 
   
   
       13 . The system of  claim 12 , wherein the ventilation setpoint is determined by averaging the determined preferred temperature of the at least two people in the zone. 
   
   
       14 . The system of  claim 12 , wherein the means for determining a number of people occupying the building zone includes an RFID sensor configured to identify RFID devices carried by people. 
   
   
       15 . The system of  claim 14 , wherein the controller retrieves an identified person's preferred temperature from a database of preferred temperatures communicably coupled to the controller, and wherein the person's preferred temperature may be set via a web-based interface. 
   
   
       16 . A method of providing HVAC control to a zone using an HVAC control system, comprising:
 determining a desired volumetric flow rate, comprising:
 computing a projected convective heat gain to the zone from people and other heat transferring objects located within the building zone, and considering at least one air property; 
   selecting a volumetric flow rate setpoint;   sending the selected volumetric flow rate setpoint to a zone ventilation device.   
   
   
       17 . The method of  claim 16 , further comprising determining the number of people occupying the zone; and
 determining a lower limit of supply airflow based on the number of people occupying the zone.   
   
   
       18 . The method of  claim 16 , further comprising:
 identifying at least one person occupying the zone;   determining a preferred temperature for the identified at least one person occupying the zone; and   using the determined preferred temperature of the at least one person occupying the zone to partially determine the zone ventilation setpoint for the building zone.   
   
   
       19 . The method of  claim 16 , further comprising:
 identifying at least two people occupying the building zone using RFID sensors configured to identify RFID devices carried by people;   determining the preferred temperature for the at least two identified people occupying the building zone and using a database of preferred temperatures associated with people;   averaging the determined preferred temperatures of the at least two people; and   using the average to compute a zone ventilation setpoint.   
   
   
       20 . The method of  claim 16 , further comprising determining the number of people occupying the zone using a wireless RFID sensor configured to identify RFID devices carried by people. 
   
   
       21 . The method of  claim 20 , further comprising determining the activity level of the people occupying the zone using the wireless RFID sensor; and
 using the determined activity level to compute the projected convective heat gain to the zone from people.   
   
   
       22 . The method of  claim 16 , further comprising:
 predicting the convective heat gain to the zone from people and other heat transferring objects located within the building zone based upon schedule information of a scheduling database; and   adjusting a volumetric flow rate setpoint prior to a scheduled meeting time.   
   
   
       23 . A controller configured to control the environment of a building zone, comprising:
 a data processor;   a zone ventilation device interface communicably coupled to the data processor, the zone ventilation device interface being configured to route a control signal to a zone ventilation device; and   a sensor interface communicably coupled to the data processor, the sensor interface being configured to accept a signal from at least one sensor located within the building zone;   wherein the data processor is configured to compute a projected convective heat gain to the building zone from people and other heat transferring objects located within the building zone based on a signal received from the sensor interface; and wherein the data processor is configured to send a control signal to the zone ventilation devices via the zone ventilation device interface based at least partially on the computed projected convective heat gain.   
   
   
       24 . The controller of  claim 23 , further comprising a means for determining a preferred temperature based on the people occupying the building zone, wherein the determined preferred temperature is considered by the processing means to determine the environment setpoint. 
   
   
       25 . The controller of  claim 23 , further comprising a communications device configured to receive scheduling information from a scheduling database, wherein the data processor is configured to predict convective heat gain to the building zone based upon the received scheduling information and to send a control signal to the zone ventilation devices via the zone ventilation device interface based on the predicted convective heat gain to the building zone. 
   
   
       26 . The controller of  claim 25 , wherein the controller causes the zone ventilation devices to provide an increased level of ventilation to the zone prior to a scheduled time of the scheduling database. 
   
   
       27 . The controller of  claim 25 , wherein the scheduling database is the primary scheduling database used by the occupants of the building zone and wherein the scheduling information is meeting information.