Retrofitting a constant volume air handling unit with a variable frequency drive
A system and methods providing real-time monitoring, management and control of a variable frequency drive retrofit to a constant volume air handling unit without making significant mechanical or control system changes. Customers and vendors are provided with a more informative and economically attractive air handling unit. The system also provides a finer granularity of control over conditioned air properties such as temperature, humidity and air quality.
1. A system comprising:
a processor; and
a memory communicatively coupled to the processor, the memory having stored therein computer-executable instructions, comprising:
a controller component configured to:
determine a temperature difference between an intake air temperature at an entrance of a heat exchange area of a constant volume air handling unit and a discharge air temperature at an exit of the heat exchange area of the constant volume air handling unit;
determine an angular velocity for a blower based at least upon the determined temperature difference to achieve a predetermined heating or cooling demand for a conditioned space; and
set at least one parameter of a variable frequency drive to cause the blower to achieve the determined angular velocity.
2. The system of claim 1 , wherein the controller is further configured to determine the angular velocity based at least upon an air quality parameter associated with the conditioned space.
3. The system of claim 1 , wherein the controller is further configured to determine the angular velocity based at least upon a motion parameter associated with the conditioned space.
4. The system of claim 1 , wherein the controller is further configured to determine the angular velocity based at least upon a damper parameter associated with a position of an outside air damper.
5. The system of claim 4 , wherein the controller is further configured to instruct a damper switch to set the outside air damper to a first position determined based upon at least one of the damper parameter, the intake air temperature, the discharge air temperature, an air quality parameter, or a motion parameter.
6. The system of claim 1 , wherein the controller is further configured to:
determine whether the discharge air temperature has reached a first temperature indicative of a cooling coil in the constant volume air handling unit beginning to freeze; and
in response to the discharge air temperature reaching the first temperature, increase the angular velocity.
7. The system of claim 1 , wherein the controller is further configured to:
determine whether the discharge air temperature has reached a second temperature indicative of a heating coil in the constant volume air handling unit beginning to overheat; and
in response to the discharge air temperature reaching the second temperature, increases the angular velocity.
8. The system of claim 1 , wherein the controller is further configured to determine an actual cost savings based upon an actual cost of the system for a historical period of time for a plurality of determined angular velocities as compared to an estimated cost for the historical period of time at a constant angular velocity.
9. The system of claim 1 , wherein the controller is further configured to determine a predicted costs savings based upon a predicted cost of the system for a future period of time for a plurality of determined angular velocities as compared to an estimated cost for the future period of time at a constant angular velocity.
10. A method comprising:
determining, by a system including a processor, an intake air temperature of air at an entrance of a heat exchange area of a constant volume air handling unit;
determining, by the system, a discharge air temperature of air at an exit of the heat exchange area of the constant volume air handling unit;
determining, by the system, a temperature difference between the intake air temperature and the discharge air temperature;
determining, by the system, an angular velocity for a blower based at least upon the determined temperature difference to achieve a predetermined heating or cooling demand for a conditioned space; and
setting, by the system, at least one parameter of the variable frequency drive to cause the blower to achieve the determined angular velocity.
11. The method of claim 10 , further comprising determining, by the system, the angular velocity based at least upon an air quality parameter associated with the conditioned space.
12. The method of claim 10 , further comprising determining, by the system, the angular velocity based at least upon a motion parameter associated with the conditioned space.
13. The system of claim 10 , further comprising determining, by the system, the angular velocity based at least upon a damper parameter associated with a position of an outside air damper.
14. The method of claim 10 , further comprising:
determining, by the system, whether the discharge air temperature has reached a first temperature indicative of a cooling coil in the constant volume air handling unit beginning to freeze; and
in response to the discharge air temperature reaching the first temperature, increasing, by the system, the angular velocity.
15. The method of claim 10 , further comprising:
determining, by the system, whether the discharge air temperature has reached a second temperature indicative of a heating coil in the constant volume air handling unit beginning to overheat; and
in response to the discharge air temperature reaching the second temperature, increasing, by the system, the angular velocity.
16. The method of claim 10 , further comprising determining, by the system, a predicted costs savings based upon a predicted cost of the method for a future period of time for a plurality of determined angular velocities as compared to an estimated cost for the future period of time at a constant angular velocity.
17. A non-transitory computer-readable medium having instructions stored thereon that, in response to execution, cause at least one device including a processor to perform operations comprising:
determining an upstream intake air temperature of air at an entrance of a heat exchange area of a constant volume air handling unit;
determining a discharge air temperature of air at an exit of the heat exchange area of the constant volume air handling unit;
determining a temperature difference between the intake air temperature and the discharge air temperature;
determining an angular velocity for a blower based at least upon the determined temperature difference to achieve a predetermined heating or cooling demand for a conditioned space; and
setting at least one parameter of the variable frequency drive to cause the blower to achieve the determined angular velocity.
18. The system of claim 17 , the operations further comprising:
determining whether the discharge air temperature has reached a first temperature indicative of a cooling coil in the constant volume air handling unit beginning to freeze; and
in response to the discharge air temperature reaching the first temperature, increasing the angular velocity.
19. The system of claim 17 , the operations further comprising:
determining whether the discharge air temperature has reached a second temperature indicative of a heating coil in the constant volume air handling unit beginning to overheat; and
in response to the discharge air temperature reaching the second temperature, increasing the angular velocity.
20. The system of claim 17 , the operations further comprising determining a predicted costs savings based upon a predicted cost of the method for a future period of time for a plurality of determined angular velocities as compared to an estimated cost for the future period of time at a constant angular velocity.