Abstract: In a compressed air purification apparatus for motor vehicles, compressed air under static pressure in a pressure conduit (3) is firstly freed of impurities such as hydrocarbon compounds and oil products and subsequently dried. To ensure effective freeing of the compressed air of impurities and water vapour and provide a compressed air purification apparatus which can be used with simple means in motor vehicles, the invention provides for the compressed air being brought, before purification, to such a temperature that the gaseous impurities in the compressed air are condensed and the water present in the compressed air is dissolved as vapour.

Abstract: A first intake air control mode of setting an intake throttle valve to (or close to) a fully-opened state and setting an EGR valve to (or close to) a fully-closed state is performed when DPF temperature and a particulate matter deposition quantity are greater than corresponding predetermined values respectively, a no-injection operation state exists, and engine rotation speed is higher than a corresponding predetermined value. A second intake air control mode of setting the intake throttle valve to (or close to) a fully-closed state and setting the EGR valve to (or close to) a fully-opened state is performed when the DPF temperature and the particulate matter deposition quantity are greater than the corresponding predetermined values respectively, the no-injection operation state exists, and the engine rotation speed is lower than the corresponding predetermined value.

Abstract: A method of providing error correction to flow velocity readings of a fluid flowing through a filter arrangement for monitoring the service life of the filter, wherein a filter arrangement, comprising a filter and a sensor device is arranged downstream of the filter, the sensor device including at least one measuring sensor for detecting the flow velocity of the fluid which flows through the filter, and a further measuring sensor for measuring the air humidity of the fluid which flows through the filter. A reading of said second sensor element provides an error correction to the first sensor element.

Abstract: A system and process for gas homogenization is disclosed. This has application in the areas of generation of gas and its conversion to electricity in downstream applications. The homogenization system minimizes variance in the gas characteristics (composition, flow, pressure, temperature), thereby rendering a steady stream of gas of consistent quality to the downstream machinery. This homogenization system can be adjusted to optimize the output gas stream for specific end-applications, or to optimize the output gas stream for different input feedstocks. This ensures that overall conversion efficiencies are maximized while keeping the process cost-effective. Such a uniform, steady output gas stream has a wide range of applications in the broad areas of generation of electricity (e.g. using internal combustion engines and combustion turbine engines), chemical synthesis (e.g.

Abstract: Described is a device for conditioning a comminuted light alloy feedstock to heat and remove impurities from the feedstock. The conditioner device includes a reaction chamber having a substrate feed port for feeding the comminuted light alloy feedstock into the reaction chamber and a discharge port for allowing the conditioned feedstock to exit the reaction chamber. A scrubber gas baffle is positioned at one end of the reaction chamber and coupled to a scrubber gas injector which is configured to inject a scrubber gas through the scrubber gas baffle at a volume and rate of flow sufficient to fluidize the feedstock in the reaction chamber. A scrubber gas heater is also provided for heating the scrubber gas to a temperature sufficient to condition the feedstock as desired.

Abstract: A scrubber for controlling carbon dioxide levels in a shipping container containing respiring produce is disclosed. The scrubber is relatively small, utilizes a gas-selective membrane having a CO2/O2 selectivity ratio greater than 1:1, and fits inside the shipping container (such as a sea van container). In contrast to current methods of controlling CO2 levels in shipping containers, such as the use of hydrated lime, the scrubbers of the present invention are efficient, relatively inexpensive, do not take up shipping space within the container, and do not present handling or disposal issues. A method for controlling the carbon dioxide levels inside a shipping container containing respiring produce, utilizing the carbon dioxide scrubbers defined, is also disclosed.

Abstract: A method of using a modular International Organization for Standardization (ISO) filter house for filtering process fluids is provided. The filter house includes a self-contained rectangular cuboid enclosure having the outside dimension of a standard, transportable ISO shipping container. The filter house has apertures for fluid flow inlet and fluid flow outlet, and a filter element for removing impurities from the fluid flow. The method includes creating one standard filter house design to be used in any multiple to meet various flow requirements. The method further includes creating a common fluid connection between the filter houses and process equipment so that the filter houses operate in parallel. A kit of modular components for filtration of a fluid is also provided. The kit includes an external structure of an ISO shipping container, vanes to direct fluid flow, and a filter element.

Abstract: In one example, a method of operating an engine having a diesel particulate filter in a vehicle, the particulate filter having a length and depth, includes performing particulate filter regeneration in response to temperature variation across the length and/or depth of the particulate filter.

Abstract: A liquid processing apparatus, includes an apparatus main body, a power room having an atmosphere separated from the clean room by a partition member, an air suction path configured to suction an air in the clean room and take the air into the power room, a temperature control part provided in the power room and configured to control at least a temperature of the air taken in via the air suction path, an air supplying path configured to supply the air from the temperature control part to the liquid processing unit, a ventilation part configured to take the air from the air suction path and supply the air via the air supplying path, and a cleaning filer configured to clean the air taken in from the air suction path.

Abstract: A dehumidification plant for granular material, comprising hopper having loading mouth and discharge mouth for granular material, upper feeding mouth in the hopper and lower delivery mouth of a gaseous medium, humidity absorbent material designed to absorb the humidity conveyed by the gaseous medium; towers arranged to contain the absorbent material; supplying arrangement designed to feed the gaseous medium to the hopper and the towers; electronic control unit; detection structure arranged to detect process variables of the plant and electrically connected with the electronic control unit. The plant further comprises distribution structure designed to distribute gaseous medium from of the towers thereby feeding it to another tower from among the towers, the distribution structure being controllable by the electronic control unit between open position, portion of the gaseous medium contained in the of the towers is fed to the towers, and closed position.

Abstract: An apparatus for controlling odor within a refrigeration appliance is provided. The apparatus includes a frame removably positioned within an airflow path configured to supply cooled air to a food storage compartment of the refrigeration appliance. The frame defines a chamber. A filter medium is positioned within the chamber. The filter medium is configured to filter air channeled therethrough and remove odorous molecules.

Abstract: An adsorption drying apparatus, in particular for drying a compressed gas, includes an adsorption chamber (11) having a plurality of adsorption conduits (101) containing an adsorption material (123), a first feeding line (106) and a first discharging line (109) disposed at a first end (111) of the adsorption chamber (11), and a second feeding line (108) and a second discharging line (107) disposed at a second end (112) of the adsorption chamber (11). The adsorption chamber (11) is rotatable with respect to the feeding and discharging lines (106, 107, 108, 109) so that the adsorption conduits may be fluidically connected in temporal alternation, wherein the gas is dried in a drying sector (102), and the adsorption material (123) is regenerated in the regeneration sector (103). The first feeding line (106) is configured such that the gas stream to be dried may be fed to the regeneration sector (103) as a full flow.

Abstract: A method and a system for providing a hypoxic environment inside an enclosed compartment with simultaneous removal of carbon dioxide and moisture produced by occupants; said method and system designed for fire prevention and for simulated altitude training, wellness and hypoxic therapy, including equine and other animal applications.

Abstract: An integrated heating system for adding heat to a feed fuel within a module by way of an integrated heating element within the body or casing of the module. The heat may be selectively added to maintain a selected temperature.

Abstract: The present invention describes a system and method for accurately measuring the temperature of a filter element. A temperature transducer, and a communications device are coupled so as to be able to measure and transmit the temperature of a filter element while in use. This system can comprise a single component, integrating both the communication device and the temperature transducer. Alternatively, the system can comprise separate temperature transducer and transmitter components, in communication with one another. In yet another embodiment, a storage element can be added to the system, thereby allowing the device to store a set of temperature values. The use of this device is beneficial to many applications. For example, the ability to read filter temperatures in situ allows improved Sterilization-In-Place (SIP) protocol compliance, since the temperatures of actual filter elements can be directly measured, rather than interpolated as is done currently.

Abstract: An electronic device includes a housing defining a chamber, a circuit board positioned in the chamber and having at least one integrated circuit, an air inlet port and an air outlet port formed in the housing, a fluid flow generator to generate an air flow across the circuit board in the chamber, and an electrostatic air filtration system to filter air entering the chamber from the air inlet port.

Abstract: An oxygen concentrator comprises a plurality of adsorbent columns, each having an inlet, an outlet and abed of adsorbent material. The oxygen concentrator also includes a vacuum pump for removing separated nitrogen rich gas from the column inlets, a control valve for controlling flow of fluids in and out of the columns, and a breakthrough sensor for signaling the position of a mass transfer zone (MTZ), the breakthrough sensor controlling operation of the control valve as a function of the breakthrough sensor signal. An electric control module (ECM) receives the signal from the breakthrough sensor, and adjusts the control valve based on the signal.

Abstract: A fuel system includes a fuel deoxygenator for removing oxygen from a liquid fuel. A vaporizer is in fluid communication with the fuel deoxygenator. The vaporizer vaporizes at least a portion of the liquid fuel to produce vaporized fuel. At least a portion of the vaporized fuel pre-mixes with oxidizer to reduce formation of undesirable emissions.

Abstract: A system and method are disclosed for providing aqueous stream purification services. The system includes at least one separation unit. Each separation unit may include a mechanical vapor recompression separator, a steam stripper, and a secondary recovery heat exchanger. The system for wastewater purification may receive water from a waste water storage, purify the water, and return the purified water to a purified water storage. The system may include a controller. The controller may include an operating conditions module configured to interpret at least one operating condition.

Abstract: A system and method are disclosed for purifying a waste fluid stream. The system includes a recirculation pump having an inlet for a recirculation stream and an outlet to expel a pressurized stream. The system includes a compressor having an inlet for an evaporation stream and an outlet for a pressurized evaporation stream. A primary heat exchanger has inlets for the pressurized stream and the pressurized evaporation stream, an internal surface area for heat transfer from the evaporation stream to the pressurized stream, and outlets for a cooled product stream and a heated pressurized stream. The heated pressurized stream is formed by heating the pressurized stream and the cooled product stream is formed by cooling the evaporation stream. The system includes an evaporation unit having an inlet for the heated pressurized stream and outlets for an evaporation stream and the recycled liquid bottoms stream.

Abstract: The invention relates to a method for controlling a heatable dehumidifier. The heating of the dehumidifier is to be actuated only when several congruent time windows within which a temperature gradient is greater than or equal to 0 could be determined during a certain period of time, i.e. the heating is to be actuated only when no air flows into the interior of the expansion vessel of the transformer.

Abstract: Pressure swing adsorption (PSA) assemblies with temperature-based breakthrough detection systems, as well as to hydrogen-generation assemblies and/or fuel cell systems containing the same, and to methods of operating the same. The detection systems are adapted to detect a measured temperature associated with adsorbent in an adsorbent bed of a PSA assembly and to control the operation of at least the PSA assembly responsive at least in part thereto, such as responsive to the relationship between the measured temperature and at least one reference temperature. The reference temperature may include a stored value, a previously measured temperature and/or a temperature measured elsewhere in the PSA assembly. In some embodiments, the reference temperature is associated with adsorbent downstream from the adsorbent from which the measured temperature is detected.

Abstract: An on-board inert gas generation system is disclosed that includes an air separation module that is configured to produce nitrogen enriched air from a non-enriched air. The non-enriched air to the air separation module has a desired operating temperature range. A compressor system is in fluid communication with the air separation module. The compressor system is configured to rotate at a speed and provide the non-enriched air to the air separation module. A controller is in communication with the compressor system and is configured to reduce the speed in response to a parameter reaching an undesired value, which would result in a non-enriched air temperature that would exceed the desired operating temperature range. The reduced speed is selected to maintain the non-enriched air temperature within the desired operating temperature range.

Abstract: Device for drying a compressed gas which consists of a compressed gas supply (2), two pressure vessels (33 and 34) which are provided with an input (37, respectively) and an output (39, 40 respectively) and a take-up point (32) for users of compressed dried gas, whereby at least two layers of desiccant (35 and 36) are provided in the pressure vessels (33 and 34), a first layer (35) made of a waterproof desiccant and a second layer (36) which is not necessarily made of a waterproof desiccant respectively, and whereby the pressure vessels (33 and 34) are provided with a second input (41, 42 respectively) for the supply of compressed gas to regenerate desiccant from the first layer (35).

Abstract: An on-board inert gas generation system is disclosed that includes an air separation module that is configured to produce nitrogen enriched air from a non-enriched air. The non-enriched air to the air separation module has a desired operating temperature range. A compressor system is in fluid communication with the air separation module. The compressor system is configured to rotate at a speed and provide the non-enriched air to the air separation module. A controller is in communication with the compressor system and is configured to reduce the speed in response to a parameter reaching an undesired value, which would result in a non-enriched air temperature that would exceed the desired operating temperature range. The reduced speed is selected to maintain the non-enriched air temperature within the desired operating temperature range.

Abstract: A system for delivering air to vehicle engines generally includes at least one air cleaner configurable to receive either conditioned air or unconditioned air and a conduit assembly coupled to the air cleaner for delivering cleaned air from the air cleaner to the vehicle engine.

Abstract: A regeneration method for a particulate filter includes estimating a quantity of particulate matter trapped within the particulate filter, comparing the quantity of particulate matter to a predetermined quantity, heating at least a portion of the particulate filter to a combustion temperature of the particulate matter, and introducing hydrocarbon fuel to the particulate filter. The hydrocarbon fuel facilitates combustion of the particulate matter to regenerate the particulate filter.

Abstract: A method of removing siloxanes from a gas that contains siloxanes and water, the method comprising: (a) expanding the gas to cool the gas and freeze at least some of the water in the gas; and (b) removing the siloxanes and frozen water from the expanded and cooled gas. The method may also include compressing the gas prior to expanding it. The step of expanding the gas may include expanding it through a turbine. The method may also include using an energy input mechanism to drive one or both of the compressor or turbine. The ice and siloxanes may be removed from the gas with a cyclonic separator.

Abstract: A liquid hydrocarbon slug-containing vessel for incorporation into a system integrating a low-pressure separator with a vapor recovery process system, and a method for regulating the temperature of a gas to be compressed by a two stage compressor so as to prevent liquification of the gas and to prevent over-heating of the compressor.

Abstract: This invention provides a method and process for the facile extraction of selected gases by means of a permeable membrane module, also known as a permeator, with effective and beneficial control of temperature the apparatus allowing temperature gradients or isothermal operation. The isolation and removal of subject gases, particularly those arising from combustion, i.e., combustion gases, is usually accomplished by means of absorber and stripper towers containing various packings to facilitate gas-liquid interaction. The inlet temperature has to be controlled but the temperature varies along the length of the tower height. In contrast, a membrane-based separation device, whether it is a permeator design or a traditional two body absorber and stripper, operates better, particularly if driven by a catalyst, under a controlled temperature regimen.

Abstract: The present invention relates to an exhaust emission control apparatus for an internal combustion engine and a process for operating it. The exhaust emission control has a particulate filter for filtering particulate matter from the exhaust of the internal combustion engine, at least one temperature sensor for detecting the temperature of the exhaust, an evaluation unit for evaluating the detected temperature, particularly with regard to a particulate mass burned during a regeneration operation of the particulate filter. The temperature sensor is positioned inside the particulate filter.

Abstract: Device for drying a compressed gas which consists of a compressed gas supply (2), two pressure vessels (33 and 34) which are provided with an input (37, respectively) and an output (39, 40 respectively) and a take-up point (32) f or users of compressed dried gas, whereby at least two layers of desiccant (35 and 36) are provided in the pressure vessels (33 and 34), a first layer (35) made of a waterproof desiccant and a second layer (36) which is not necessarily made of a waterproof desiccant respectively, and whereby the pressure vessels (33 and 34) are provided with a second input (41, 42 respectively) for the supply of compressed gas to regenerate desiccant from the first layer (35).

Abstract: A fuel system includes a fuel deoxygenator for removing oxygen from a liquid fuel. A vaporizer is in fluid communication with the fuel deoxygenator. The vaporizer vaporizes at least a portion of the liquid fuel to produce vaporized fuel. At least a portion of the vaporized fuel pre-mixes with oxidizer to reduce formation of undesirable emissions.

Abstract: Data of a barometric pressure that a barometric pressure sensor outputs, and data of an air volume that an air-volume sensor outputs are input into a system control circuit. The system control circuit is provided with a table storing portion. In the table storing portion, a control table is stored. The control table is formed of a plus supplied-voltage value to fan power set by a barometric pressure value and an air-volume value, and a warning instruction. In a case that the warning instruction is selected based on the barometric pressure value and the air-volume value, the system control circuit turns on a warning-use LED so as to inform a user that a filter is clogged.

Abstract: An object of the present invention is to provide a honeycomb structural body for use in a filter, which can be provided with a large amount of catalyst, can suppress an increase in pressure loss upon collecting particulates, can have a high particulate collecting capability and can efficiently carry out a regenerating process and a toxic gas purifying process. The honeycomb structural body of the present invention is a pillar-shaped honeycomb structural body that is mainly composed of inorganic fibers and has a structure in that a large number of through holes are placed in parallel with one another in the length direction with a partition wall interposed therebetween. Herein, the inorganic fibers, which form the honeycomb structural body, are arranged in such a manner that more fibers are aligned along a face perpendicular to the forming direction of the through holes rather than aligned along a face in parallel with the forming direction of the through holes.

Abstract: In one embodiment an electronic device comprises a housing defining a chamber, a circuit board positioned in the chamber and comprising at least one integrated circuit, an air inlet port and an air outlet port formed in the housing, a fluid flow generator to generate an air flow across the circuit board in the chamber, and an electrostatic air filtration system to filter air entering the chamber from the air inlet port.

Abstract: A method of providing gas to a system which separates from a pressurized supply gas, product gas, includes conditioning the supply gas by both cooling and drying the supply gas.

Abstract: An improved control scheme is set forth for an adsorption process that removes water and carbon dioxide (CO2) from a feed gas using a hybrid of both temperature swing (i.e. TSA) and pressure swing (PSA) to regenerate the adsorbent. The control scheme comprises adjusting the quantity of heat to be provided by the regeneration gas as a function of temperature data taken within a strategic portion of the water selective adsorbent zone. The strategic portion corresponds to the location for the desired transition from regeneration by temperature swing, to regeneration by pressure swing. In a preferred embodiment of the present invention, said quantity of regeneration heat is also adjusted as a function of the water content of the feed gas.

Abstract: Pressure swing adsorption (PSA) assemblies with temperature-based breakthrough detection systems, as well as to hydrogen-generation assemblies and/or fuel cell systems containing the same, and to methods of operating the same. The detection systems are adapted to detect a measured temperature associated with adsorbent in an adsorbent bed of a PSA assembly and to control the operation of at least the PSA assembly responsive at least in part thereto, such as responsive to the relationship between the measured temperature and at least one reference temperature. The reference temperature may include a stored value, a previously measured temperature and/or a temperature measured elsewhere in the PSA assembly. In some embodiments, the reference temperature is associated with adsorbent downstream from the adsorbent from which the measured temperature is detected.

Abstract: Pressure swing adsorption (PSA) assemblies with temperature-based breakthrough detection systems, as well as to hydrogen-generation assemblies and/or fuel cell systems containing the same, and to methods of operating the same. The detection systems are adapted to detect a measured temperature associated with adsorbent in an adsorbent bed of a PSA assembly and to control the operation of at least the PSA assembly responsive at least in part thereto, such as responsive to the relationship between the measured temperature and at least one reference temperature. The reference temperature may include a stored value, a previously measured temperature and/or a temperature measured elsewhere in the PSA assembly. In some embodiments, the reference temperature is associated with adsorbent downstream from the adsorbent from which the measured temperature is detected.

Abstract: An inerting system and method characterized by a primary air separation module configured to communicate with an upstream source of pressurized air at elevated temperature for production of a primary downstream flow of nitrogen-enriched air to be delivered to a space to be inerted; a secondary air separation module configured to communicate with the upstream source of pressurized air at elevated temperature for production of a supplemental downstream flow of nitrogen-enriched air to be delivered to a space to be inerted when high nitrogen-enriched airflow is desired during a high flow period; and a flow controller configured to provide a warming flow through the secondary air separation module to heat the secondary air separation module to above ambient temperature during a warming period other than the high flow period.

Abstract: The present invention discloses a system for flue gas treatment, wherein the provided system comprises a quench module, a first control module, a filter collecting module, a wet scribing module and a regeneration module. In this system, parts of the particles contained in flue gas are removed in the quench module and the wet scribing module by a first scrubbing solution, and then in wet scribing module a second scrubbing liquid containing particles is formed. Next, the second scrubbing solution is treated in the regeneration module to form a third scrubbing solution, wherein the third scrubbing solution is then fed back to the quench module and/or the wet scrubbing module to substitute the first scrubbing solution for repeating what originally performed via the first scrubbing solution. Furthermore, this invention discloses a method for flue gas treatment.

Abstract: A liquid processing apparatus, includes an apparatus main body, a power room having an atmosphere separated from the clean room by a partition member, an air suction path configured to suction an air in the clean room and take the air into the power room, a temperature control part provided in the power room and configured to control at least a temperature of the air taken in via the air suction path, an air supplying path configured to supply the air from the temperature control part to the liquid processing unit, a ventilation part configured to take the air from the air suction path and supply the air via the air supplying path, and a cleaning filer configured to clean the air taken in from the air suction path.

Abstract: An apparatus and method of conditioning humidity and temperature in the process airstream of a desiccant dehumidifier used to dry moisture-laden spaces and structures by replacing moisture-laden air with dehumidified air to increase the rate of water evaporation within the affected areas. A heat-modulating dehumidifier comprises a dehumidification assembly having a desiccant rotor assembly, a post-process pre-reactivation heat exchanger assembly, a reactivation air bypass damper, a reactivation heater, and a control system. The apparatus regulates the temperature level of the dehumidified air exiting the apparatus by extracting heat from the dehumidified air prior to its ejection into an affected area, using a bypass damper that controls the amount of heat transfer from the dehumidified air to a second airstream entering the apparatus.

Abstract: A flow-through carbon adsorption device is provided with leads for imposing an electric current and with a temperature sensor at the desorption flow exit. The temperature sensor and electric current source are controlled by a controller. In adsorption mode, no current flows through the device. Hydrocarbons are adsorbed in the device before reaching atmosphere. In desorption mode, the temperature sensor and electric source are activated by the controller. Electric energy is converted to heat energy within the device. Air is drawn in reverse flow through the device. Because desorption is endothermic, the carbon bed becomes progressively cooler during desorption. When desorption is complete, the temperature of the device begins to rise and the controller shuts down the temperature probe and the electric heating system. Thus, full desorption of the device is assured without significant waste of electricity or compromise of subsequent adsorptive capacity of the device after desorption is complete.

Abstract: A method in which all or some of the particles contained in the exhaust gases of a diesel engine are retained on particle filters and burnt due to the action of a combustion catalyst. At least a part of the particle filters are obstructed when the temperature ?g of the exhaust gases for filtration is equal to or less than a threshold temperature ?s, so as to limit or avoid cooling of the obstructed part of the particle filters and to maintain the same at a temperature ?o greater than or equal to ?s up until the time when ?g becomes greater than ?s again and thus permit accelerated regeneration of the obstructed part of the particle filters. Also disclosed is an exhaust gas filtration device which permits the carrying out of the filtration method with continuous and regular regeneration of the particle filters.

Abstract: Method of operating an oxygen-permeable mixed conducting membrane having an oxidant feed side and a permeate side, which method comprises controlling the differential strain between the oxidant feed side and the permeate side by varying either or both of the oxygen partial pressure and the total gas pressure on either or both of the oxidant feed side and the permeate side of the membrane while changing the temperature of the membrane from a first temperature to a second temperature.

Abstract: The present invention provides a system and method for generation of nitrogen enriched air for inerting aircraft fuels tanks. One embodiment of the present invention includes a duct assembly; a primary heat exchanger; a gas generating system heat exchanger; a first temperature sensor; a second temperature sensor; a controller monitor; a valve; an air separation module assembly having a primary module and a secondary module; at least one flow control orifice; and a pressure sensor. The present invention utilizes a minimal complement of components and streamlined processes, thus minimizing structural and operational costs while optimizing performance and safety features.

Abstract: Methods for extracting and compressing an inert gas from an exhaust gas of an engine relate to providing an inert gas processing system including a multi-stage gas compressor to receive the exhaust gas from an exhaust gas processing system, a cooling and extraction system to receive the exhaust gas from each stage of the multi-stage gas compressor and remove liquids from the exhaust gas, and a controller to monitor operation of the inert gas processing system. The methods include processing the exhaust gas before each stage of the multi-stage gas compressor to clarify the inert gas in the exhaust gas, processing the exhaust gas after each stage of the multi-stage gas compressor to clarify the inert gas in the exhaust gas and compressing the inert gas processed for export from the inert gas processing system.

Abstract: A method and system for detecting and predicting air filter condition for an air handling system operates by determining a system resistance to air flow. The system resistance is utilized to determine a detection statistic indicative of current filter condition and to predict remaining life of the air filter. The system resistance is determined using models that approximate the expected operation of the air handling system. The approximation is then compared to actual values to obtain a difference. Once the difference between the approximated value exceeds a threshold value, an alarm is initiated that is indicative of system resistance. The remaining air filter life is then determined by using historically gathered data, or by using a known degradation rate of the air filter. Once the remaining life of the air filter is estimated, replacement can be scheduled that would coincide with other maintenance.