TECHNICAL FIELD

This disclosure relates to monitoring technology and, for example, sensors for enthalpy measurement.

BACKGROUND

Forced air heating, ventilating and air conditioning (HVAC) units perform cooling functions by using a refrigeration cycle to remove heat from air that is circulated over evaporator coils, and heating functions by using a furnace, heat pump, or other heating element to heat air from a source vent and blowing the heated air through return vents. Air contains two kinds of heat, sensible heat, which is attributed to the temperature of air molecules, and latent heat, which is attributed to the heat of vaporization of the water vapor contained in air. By measuring the temperature and humidity at the source and return vents of a HVAC unit, the amount of heat added or removed by the HVAC unit may be calculated to determine the system load due to removing sensible versus latent heat.

SUMMARY

In some implementations, sensors are used to calculate the enthalpy delta between source vents and return vents in a HVAC system. For example, techniques are described for monitoring enthalpy measurements using temperature and humidity sensors to track HVAC unit health, identify and quantify sources that reduce system efficiency, and develop optimized heating/cooling schemes for an individual property based on data measured by the sensors.

In some implementations, a method may be performed by one or more computers, the method includes: obtaining, from one or more sensors associated with a heating, ventilating, and air conditioning (HVAC) system, (i) temperature data including a source vent temperature measurement and a return vent temperature of the HVAC system, and (ii) humidity data including a source vent humidity measurement and a return vent humidity measurement of the HVAC system; computing, based at least on the obtained temperature data and the humidity data, an enthalpy measurement associated with operation of the HVAC system; determining that the computed enthalpy measurement indicates an abnormality associated with operation of the HVAC system; and in response to determining that at least one of the computed enthalpy measurement indicates an abnormality associated with an operation of the HVAC system, taking action related to performance of a particular maintenance operation associated with the HVAC system.

Implementations may include one or more optional features. For instance, in some implementations, obtaining the temperature data and the humidity data includes periodically obtaining the temperature and humidity data over a particular period of time, and determining that the computed enthalpy measurement indicates an efficiency issue associated with operation of the HVAC system includes determining that the computed enthalpy measurements indicates an efficiency issue associated with operation of the HVAC system over the particular period of time.

In some implementations, the enthalpy measurement includes an amount of sensible heat removed by the HVAC system from at least a portion of a property associated with the HVAC system.

In some implementations, the enthalpy measurement includes an amount of latent heat removed by the HVAC system from at least a portion of a property associated with the HVAC system.

In some implementations, the method may further include computing a relative HVAC system efficiency score based at least on the computed enthalpy measurement.

In some implementations, the HVAC system efficiency score indicates heating or cooling losses that contribute to system inefficiency associated with operation of the HVAC system.

In some implementations, computing the relative HVAC system efficiency score includes comparing the obtained temperature data and humidity data to reference temperature data and reference humidity data that are each associated with predetermined efficient operation of the HVAC system.

In some implementations, the one or more sensors associated with the HVAC system comprise an anemometer that determines a volumetric airflow produced by the HVAC system.

In some implementations, the method further includes: obtaining, from the anemometer, airspeed data that includes a source vent airspeed measurement and a return vent airspeed measurement associated with the HVAC system; and computing the enthalpy measurement associated with operation of the HVAC system is based at least on the obtained airspeed data.

In some implementations, determining that the computed enthalpy measurement indicates an efficiency issue associated with operation of the HVAC system includes: comparing the obtained temperature data against reference data that includes a user-defined set point temperature; determining that a difference between a value of the user-defined set point temperature and a value of either the return vent temperature or the source vent temperature exceeds a predetermined threshold; and in response to determining that the difference exceeds the predetermined threshold, identifying an efficiency issue associated with operation of the HVAC system.

Implementations of the described techniques may include hardware, a method or process implemented at least partially in hardware, or a computer-readable storage medium encoded with executable instructions that, when executed by a processor, perform operations.

The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features will be apparent from the description and drawings.

