Enhanced HVAC performance monitoring system and method thereof
View Patent ↗A system and method of monitoring the performance of an HVAC system including a controller in communication with an HVAC unit where the method includes monitoring environmental conditions using a controller. Environmental conditions, such as indoor air temperature, indoor humidity and outdoor temperature are measured and used to compute performance parameters that help diagnose HVAC performance problems. The rate of change of indoor air temperature (IATR) and rate of change of indoor humidity (IDHR) are computed and used to determine the sensible heat ratio of the cooling system. The sensible heat ratio, which may or may not be adjusted for transient startup, is used in concert with product performance data, indoor air temperature, indoor humidity, and outdoor air temperature to determine cooling system airflow.
1 . A method for monitoring performance of a heating, ventilation, and air condition system for determining indoor air temperature change rate (IATR) and indoor air dehumidification rate (IDHR) to compute the sensible heat ratio (SHR) of a cooling system for a conditioned space, comprising:
initiating a performance evaluation period through an HVAC controller communicatively coupled to the HVAC system;
monitoring the operation of the HVAC system using a monitoring system controller, wherein a monitoring system controller comprising a processor and memory executes instructions that, during HVAC operation, record outdoor air temperature, indoor air temperature, indoor relative humidity, and HVAC ON/OFF status at a prescribed interval;
obtaining baseline data for one or more environmental factors from at least one of the following:
the HVAC controller communicatively coupled to the monitoring system controller;
one or more sensors communicatively coupled to the HVAC controller; or
one or more or databases communicatively coupled to the monitoring system controller;
generating a IATR and IDHR during the performance evaluation period;
generating SHR value at intervals during the performance evaluation cycle using a performance analysis algorithm and at least one of the following environmental factors:
obtained environmental data;
historical measured performance data for the HVAC system; or
manufacturer system performance product data; and
generating an airflow value based upon the SHR value, wherein an outside airflow value into the conditioned space can be determined by plotting outdoor air temperature versus indoor humidity and determining the slope of the best-fit line;
and generating, via a user interface, an alert when the circulating airflow value or the normalized outside-air entry exceeds a predetermined threshold for a predetermined duration.
2 . The method of claim 1 , wherein the SHR value is adjusted to an equivalent steady state value based on an average system run-time per cycle to account for startup transient.
3 . The method of claim 1 , wherein the SHR values used to generate the airflow value are based upon SHR values within a pre-determined range.
4 . The method of claim 1 , wherein a cooling system airflow is determined using the SHR value and one or more of the following factors: measured indoor air temperature, outdoor air temperature and indoor humidity values applied to cooling system performance data.
5 . The method of claim 1 , wherein an outside airflow value into the conditioned space can be determined by plotting outdoor air temperature versus indoor humidity and determining the slope of the best-fit line.
6 . The method of claim 1 , wherein an outside airflow value into the conditioned space can be determined by plotting outdoor humidity vs. indoor humidity and determining the slope of the best-fit line.
7 . The method of claim 1 , wherein the outside airflow value into the conditioned space is adjusted using a standard reference condition, wherein the HVAC controller automatically adjusts according to the alert.
8 . The method of claim 1 , wherein the outside airflow value is determined by pounds of outdoor moisture per pounds of air versus pounds of indoor moisture per pound of air.
9 . The method of claim 1 , wherein a circulating airflow value is recorded and plotted over a pre-determined period of time, and further comprising computing indoor wet-bulb temperature from the measured indoor air temperature and indoor relative humidity and, using manufacturer system performance product data, determining a circulating airflow value by interpolating the performance data with the computed indoor wet-bulb, the measured outdoor air temperature, and the computed SHR.
10 . The method of claim 9 , wherein the circulating airflow value is further adjusted based upon the following equation: Adjustment=[(IATmeasured−OATaverage)/(IATmeasured−OATmeasured)] 1/2 , wherein IAT is indoor air temperature and OAT is outdoor air temperature.
11 . The method of claim 1 , wherein the monitoring system is further communicatively coupled to a database to retrieve manufacturer performance data over a network API.
12 . The method of claim 1 , further comprising generating the IATR and the IDHR from the recorded time-series data, wherein the prescribed interval is between about 5 seconds and about 5 minutes.
13 . A method for monitoring performance and determining indoor air temperature change rate (IATR) and indoor air dehumidification rate (IDHR) to account for exterior airflow within a conditioned space, comprising:
initiating a performance evaluation period through an HVAC controller communicatively coupled to the HVAC system;
monitoring the operation of the HVAC system using a monitoring system controller wherein a monitoring system controller comprising a processor and memory executes instructions that, during HVAC operation, record outdoor air temperature, indoor air temperature, indoor relative humidity, and HVAC ON/OFF status at a prescribed interval;
obtaining baseline data for one or more environmental factors from at least one of the following:
the HVAC controller communicatively coupled to the monitoring system controller;
one or more sensors communicatively coupled to the HVAC controller; or
one or more or databases communicatively coupled to the monitoring system controller;
generating a IATR and IDHR during the performance evaluation period;
generating at least one of the following values:
circulating airflow value or an outdoor airflow, wherein the outside airflow value into the conditioned space can be determined by plotting outdoor air temperature versus indoor humidity and determining the slope of the best-fit line; and generating, via a user interface, an alert when the circulating airflow value or the normalized outside-air entry exceeds a predetermined threshold for a predetermined duration.
14 . The method of claim 13 , wherein the outside airflow value into the conditioned space can be determined by plotting outdoor humidity vs. indoor humidity and determining the slope of the best-fit line.
15 . The method of claim 13 , wherein the circulating airflow value is determined by generating SHR values at intervals during the performance evaluation cycle using a performance analysis algorithm and at least one of the following environmental factors:
obtained environmental data;
historical measured performance data for the HVAC system; or
manufacturer system performance product data.
16 . The method of claim 15 , wherein the SHR value is adjusted to an equivalent steady state value based on an average system run-time per cycle to account for startup transient.
17 . The method of claim 15 , wherein the SHR values used to generate the circulating airflow value are based upon SHR values within a pre-determined range.
18 . The method of claim 15 , wherein the circulating airflow value is determined using the SHR value and one or more of the following factors: measured indoor air temperature, outdoor air temperature and indoor humidity values applied to cooling system performance data.
19 . A system for monitoring and evaluation of an HVAC system for a conditioned space, comprising:
a monitoring system controller having a processor and memory, wherein the HVAC system further includes an HVAC controller, wherein executes instructions to record outdoor air temperature, indoor air temperature, indoor relative humidity, and ON/OFF system status at a prescribed interval;
at least one sensor communicatively coupled to the monitoring system controller, wherein the sensor is configured to monitor one or more environmental parameters inside a structure;
a memory; and
a transceiver configured to communicate with one or more external sources for obtaining monitoring data including at least one of the following:
environmental information;
HVAC performance data provided by a manufacturer; or
measured HVAC data;
wherein the monitoring system controller is configured to generate at least one of the following:
adjusted air temperature change rate (IATR) value (IATRadj), indoor air dehumidification rate (IDHR), Sensible Heat Ratio (SHR), circulating airflow and/or outside air entry into the conditioned space on an ongoing basis, and wherein the outside airflow value into the conditioned space can be determined by plotting outdoor air temperature versus indoor humidity and determining the slope of the best-fit line; and
generating, via a user interface, an alert when the circulating airflow value or the normalized outside-air entry exceeds a predetermined threshold for a predetermined duration.
20 . The system of claim 19 , wherein the environmental information comprises at least one of the following: indoor air temperature, outdoor air temperature, indoor humidity, outdoor humidity, or barometric pressure.