Air filter monitoring system
View Patent ↗A real-time monitoring system that monitors various aspects of the operation of a refrigerant-cycle system is described. The system includes a processor that measures power provided to the refrigerant-cycle system and gathers data from one or more sensors in connection with a filter element.
1. A monitoring system for a heating, ventilation, or air conditioning (HVAC) system of a residential or commercial building, the monitoring system comprising:
a light source disposed at one side of a filter element of the HVAC system and configured to output light;
a light sensor disposed on an opposite side of the filter element and configured to measure an amount of the light transmitted through the filter element; and
a computer system configured to
receive values of the measured amount of light,
determine a baseline level based on one of the measured light values,
compare a present one of the measured light values to the baseline level, and
selectively generate a signal indicating dirtiness of the filter element in response to the present one of the measured light values falling below a predetermined percentage of the baseline level.
2. The monitoring system of claim 1 , wherein the computer system is configured to update the baseline level in response to replacement of the filter element.
3. The monitoring system of claim 1 , wherein the computer system is configured to determine the baseline level during an initial calibration mode of the HVAC system.
4. A method of monitoring a heating, ventilation, or air conditioning (HVAC) system of a residential or commercial building, the method comprising:
measuring an amount of light transmitted through a filter element from a light source disposed at one side of the filter element using a light sensor disposed at an opposite side of the filter element;
receiving values of the measured amount of light;
determining a baseline level based on one of the measured light values;
comparing a present one of the measured light values to the baseline level; and
selectively generating a signal indicating dirtiness of the filter element in response to the present one of the measured light values falling below a predetermined percentage of the baseline level.
5. The method of claim 4 , further comprising updating the baseline level in response to replacement of the filter element.
6. The method of claim 4 , further comprising determining the baseline level during an initial calibration mode of the HVAC system.
7. The method of claim 4 , further comprising generating the signal in response to a reduction in airflow through the filter element.
8. The method of claim 7 , further comprising determining the reduction in airflow based on a comparison of (i) an expected temperature drop of air across an evaporator of the HVAC system and (ii) a measured temperature drop of air across the evaporator.
9. The method of claim 7 , further comprising determining the reduction in airflow based on measurements from an airflow sensor.
10. The method of claim 4 , further comprising generating the signal based on an amount of time that the filter element has been installed in the HVAC system.
11. The method of claim 4 , further comprising generating the signal based on an amount of time that a circulator blower of the HVAC system has been blowing air through the filter element.