Patent Application
20150292985
The invention relates to heating, ventilation, air conditioning, and refrigeration (HVAC/R or, more commonly HVAC) systems. More specifically, the invention relates to a system that includes an apparatus and method for monitoring the operation of HVAC systems; acquiring, managing, sharing, and reporting data related to the HVAC systems; assessing the performance of HVAC systems; and installing, troubleshooting, and servicing the HVAC systems.
HVAC systems are widely known. “Air conditioning” is a general term for a process that maintains comfort conditions in a defined area. Air conditioning includes sensible heating of the air (referred to generally as heating), sensible cooling and/or dehumidifying of the air (referred to generally as air conditioning, which can be abbreviated as A/C), humidifying the air, and cleaning or filtering the air. HVAC or air conditioning, as used herein, also includes refrigeration systems (e.g., coolers and freezers of consumer, commercial and industrial scale). Therefore, in this description, HVAC can encompass and describe any heating, ventilation, air conditioning, or refrigeration process or equipment. Also, an “A/C unit” can refer to conventional air conditioning unit, a refrigeration unit, or a heat pump.
All conventional A/C or refrigeration systems share the same basic components: a compressor, a condenser coil, a metering device, and an evaporator coil. Compressors compress the gaseous refrigerant and turn it into a subcooled liquid. Condenser coils to allow the refrigerant dissipate heat and become a sub cooled liquid. Metering devices control the flow of the sub cooled refrigerant into the evaporator coil. Evaporator coils expose the refrigerant to the system load turning the refrigerant into a superheated gas. Common metering devices are capillary tubes and in new systems Thermostatic Expansion Valves (TXVs).
The study of air and its properties is called psychrometrics. Typical psychrometric units of measure are dry bulb temperature, wet bulb temperature, relative humidity and enthalpy. HVAC technicians study psychrometrics to accurately predict the final properties of the conditioned air and also to determine if the conditioning equipment is performing the way it was engineered to operate. Air has mass and weight and can therefore store heat energy. The amount of heat that the air can store is dependent upon the conditions of the air. By determining the mass flow rate and understanding the properties of the air and rules of psychrometrics, the amount of heat added or removed from the air by the conditioning device can be quantified. Understanding system airflow is critical to understanding system performance.
The phase change of a refrigerant (from liquid to gas and back to liquid) in a closed system is what allows the refrigerant to transfer thermal energy. To determine the phase state and energy carrying capacity of a refrigerant at any point in the system both the refrigerant pressure and temperature must be known. Pressure gauges are typically used to measure refrigerant pressures and contact thermometers are used to measure refrigerant line (tube) temperatures to infer the refrigerant temperature.
Measurements as typically taken by technicians on their own mean little without knowledge of the design operation. All manufacturers of quality listed equipment have their systems tested and efficiency verified to Air-Conditioning, Heating, and Refrigeration Institute (AHRI) standards. Other independent testing laboratory standards could also be used for testing and efficiency verification. Units having an energy guide label have been tested, and their efficiency can only be guaranteed if the components are matched, the system refrigerant charge is correct, the airflow is correctly set, and the system is installed per the manufacturer's instructions including proper sizing of the equipment.
To achieve the desired efficiency, all manufacturers design their equipment to operate at its rated capacity at one set of conditions at its peak performance. These conditions are known as the AHRI Standard Conditions and are as follows:
All equipment listed in the AHRI directory operates at rated capacity under the AHRI standard conditions. Because the AHRI standard conditions are at the high end of the normal range for human comfort, Standard Operating Conditions, or common operating conditions have been established as design conditions for the equipment in the field.
Under these conditions the equipment can have a slightly lower operating capacity, and the equipment will operate with different operating characteristics. Along with the standard operating conditions, conditions for airflow and coil temperatures and operating range have also been established. Most if not all manufacturers design these grades of equipment for a nominal 400 CFM airflow per ton for A/C cooling, and 450 CFM/ton for heat pumps.
Government standard tests determine the energy efficiency rating of residential HVAC equipment (cite CFR). This rating is known as Seasonal Energy Efficiency Ratio, or SEER. Higher SEER ratings mean more efficient equipment. The following Tables illustrate some characteristics and nominal operating ranges for air conditioning equipment of these standard grades in certain design operating conditions:
When charging a refrigeration system, the following steps should be followed:
Charge directly by superheat or subcooling.
Deviation from the correct charge will have a negative impact on the performance or operation of the refrigeration system. Systems utilizing a fixed metering device without any other mechanical problems and proper airflow and load will exhibit the following symptoms if improperly charged to a low charge (undercharge):
Systems utilizing a fixed metering device without any other mechanical problems and proper airflow and load will exhibit the following symptoms if improperly charged to a high charge (overcharge):
Systems utilizing a TXV without any other mechanical problems and proper airflow and load will exhibit the following symptoms if improperly charged to a low charge (undercharge):
Systems utilizing a TXV without any other mechanical problems and proper airflow and load will exhibit the following symptoms if improperly charged to a low charge (undercharge):
Industry studies show that approximately 70% of residential air conditioning systems are operating with refrigerant charge and airflow problems. Unlike lab testing done under a single set of closely held conditions, charging an air conditioning system in the field by a technician is often a complicated and dynamic process due to nonstandard conditions and constantly changing load conditions that technicians typically encounter. As load conditions change or vary from standard conditions inside or outside (ambient conditions) the conditioned space, so do performance and operational targets. System pressures, saturation temperatures, superheat, subcooling, airflow latent sensible split, power consumption, and work output all vary as the load and or the power supply (voltage) increases or decreases. Installation factors like line set length, lift in suction line insulation, and duct design also affect performance. Additionally as a system is serviced (particularly as refrigerant is added or removed) the operational characteristics again vary as the system reaches a new point of equilibrium which again changes the capacity and the rate which the sensible and latent load is handled. Determining when this new state of equilibrium is reached is also a challenge that can lead to excessive wait times to complete service.
Due to a constantly moving target, and variables associated with the installation often not accounted for in the field, acquisition and management of the data used to resolve the target performance indicators must also be as dynamic as the system itself to more accurately evaluate the performance of the system in field practice. Managing all of the data independently and manually requires the technician to carefully and quickly gather the measurement data, use several look up tables, and make manual calculations which can result in many errors from simple transcription to that of calculation or even resulting change in load conditions faster than the data can be hand obtained. Additionally, readings and calculations are not humanly possible in real time; and the variables are changing in real time presenting, at best, a fuzzy picture of the operational performance. These problems are amplified under low load and during periods of low ambient conditions due to system characteristics and the short amount of time that the system operates to satisfy the load requirements. Manual calculation is less accurate and subject to more error and cumbersome techniques making it often impractical to do in many field installations.
The smart HVAC manifold system is designed to constantly and dynamically manage the data acquisition process and to measure and calculate the performance indicators and output as the load conditions and/or equipment operation change, taking into account variables in the installation that can impact performance. Both visually, and by a very specific data sets, the performance of the equipment and the installation can quickly be assessed and specific problems identified along with suggestions of typical faults or problems that may need addressed by the technician.
The smart HVAC manifold system also provides a means of quickly and electronically handling the manual data acquisition process which would include component and/or brand, system model and serial numbers, equipment location (Global Positioning System (or GPS) tagging), customer name, environmental conditions that effect performance and performance measurement (weather data and elevation), and supports photo, voice and text documentation. These features streamline data acquisition, allow remote support, and minimize transcription errors also preventing data manipulation (gaming of the input of false, repeated or physically impossible data) by technicians when servicing equipment or commissioning or retro commissioning the system.
The smart HVAC manifold system can quickly lead a technician in the right direction with onboard diagnostics. By making real time measurements and comparing those measurements to engineered data, the smart HVAC manifold system can help a technician isolate the potential problem and suggest possible solutions to typical charge airflow and load related problems. This approach streamlines the troubleshooting process making the technician faster and more accurate at isolating the fault in the system.
Remote troubleshooting problems plague the HVAC industry today due to time consuming, frustrating, and tedious processes and the need to provide remote support to a struggling technician facing a large number of variables in assessing performance and troubleshooting substandard operation of air-conditioning equipment. The smart HVAC manifold system will allow for remote access to measurement data from anywhere in the world via a wireless internet connection. This allows for remote support from the manufacturer or a lead technician or a master technician to assist the field technician. Also the smart HVAC manifold system platform will allow for photo and/or video documentation as a “second set of eyes” at the equipment/installation site along with weather and location data providing additional information that will aid in the remote troubleshooting process. From the remote location any interested party may view (in real-time) the actual equipment performance.
To achieve the best performance, test instruments used in HVAC system evaluation should be tested for accuracy or calibrated on a regular basis. Field calibration verification is often done with a pure refrigerant at a known saturation temperature or pressure and with a reference instrument or a reference measurement, such as a distilled water ice bath. The smart HVAC manifold system allows for calibration offset through the software and into the tool within a predefined limit. Sensors can be offset to a reference or averaged. Because many of the measurements are differential and not absolute, the ability to provide an averaging offset allows for higher accuracy when determining a change in temperature or enthalpy across a coil. This field calibration process also allows the tool to meet energy efficiency program requirements (programs are often run by utilities and/or their consultants) that specify a calibration verification and a calibration protocol.
According to one aspect, a smart manifold system for monitoring the operation of an HVAC unit includes a smart manifold adapted to obtain measurement data related to the operating conditions of the HVAC unit. A smart platform is adapted to communicate wirelessly with the smart manifold and acquire the measurement data from the smart manifold. The smart platform is also adapted to ensure that measurement data is free from any user manipulation or modification, and to tag any measurement data so ensured as verified data.
According to other aspects, the smart platform can be further adapted to transmit the verified data to a remote platform for at least one of storage, report generation, and the performance of analytics. The smart platform can be further adapted to transmit the verified data via a wireless connection. The wireless connection can include an internet connection.
According to other aspects, the smart platform can include at least one of a smart phone and a tablet computer. The remote platform can include at least one of a remote server, a cloud based storage platform, and a remote computer. The measurement data can include data from one or more inputs comprising at least one of wired inputs, direct wireless inputs, and indirect wireless inputs.
According to other aspects, the smart platform can be adapted to tag measurement data as being verified as it is received from the smart platform. The smart manifold can also be adapted to tag as non-verified data any measurement data or data derived from measurement data that has been manipulated directly or indirectly through user input.
According to other aspects, the smart platform can be adapted to prevent the user manipulation of the selected measurement data to maintain that data as verified data. The smart platform can also be adapted to include user profile data comprising a security clearance level. The security clearance level can determine whether the associated user is permitted to manipulate any data and, if so, which data the user can manipulate.
According to another aspect, a method for monitoring the operation of an HVAC unit includes obtaining, via a smart manifold, measurement data related to the operating conditions of the HVAC unit. The method also includes communicating wirelessly with the smart manifold via a smart platform to acquire the measurement data from the smart manifold. The method also includes ensuring via the smart platform that measurement data is free from any user manipulation or modification. The method further includes tagging via the smart platform any ensured measurement data as verified data.
According to other aspects, the method can include transmitting the verified data to a remote platform for at least one of storage, report generation, and the performance of analytics. The can include transmitting the verified data via a wireless connection.
According to other aspects, the tagging step can include tagging the measurement data as being verified as it is received from the smart platform. The method can also include tagging as non-verified data any measurement data or data derived from measurement data that has been manipulated directly or indirectly through user input can be tagged as non-verified data.
According to other aspects, the method can also include preventing user manipulation of the selected measurement data to maintain that data as verified data. The method can also include the steps of including user profile data comprising a security clearance level, determining based on the security clearance level whether an associated user is permitted to manipulate any data, and determining which data the associated user can manipulate.
The invention relates to HVAC systems. More specifically, the invention relates to a system that includes an apparatus and method for monitoring the operation of A/C units; acquiring, managing, sharing, and reporting data related to the A/C units; assessing the performance of A/C units; and installing, troubleshooting, and servicing the A/C units. One particular unit to which the invention relates is shown in
The A/C unit 10 shown in includes a compressor 12, an evaporator 14, a condenser 16, and an expansion device 20. The expansion device 20 may, for example, be a fixed orifice device, capillary tube device, piston device, or thermostatic expansion valve (TXV). Refrigerant flows through piping 18 in a direction indicated generally by arrows in
The compressor 12 and condenser 16 are housed, along with a fan 32, in a housing 30 situated outside the structure S. The compressor 12 delivers high temperature, high pressure superheated refrigerant in vapor form to the condenser 16 via hot gas or discharge line 22. The fan 32 draws ambient air 34 into the housing 30 through coils of the condenser 16. The condenser 16 transfers heat from the heated refrigerant in the coils to the ambient air 34, and the fan 32 discharges the heated discharge air 36 from the housing 30. The refrigerant vapor in the condenser 16 cools as it transfers heat to the ambient air 34.
As the refrigerant cools, it changes from a vapor to a liquid by desuperheating, saturating and finally subcooling. The liquid refrigerant leaves the condenser 16 as a subcooled liquid and flows as a medium temperature, high pressure liquid through liquid line 40 to the expansion device 20. The refrigerant undergoes a pressure drop through the expansion device 20, which causes flashing of some of the liquid to vapor, (Flash Gas) and resulting temperature drop as some of the refrigerant changes state from liquid to vapor of the now saturated liquid refrigerant. Low pressure, low temperature saturated liquid refrigerant flows into the evaporator 14 via distributor line 42.
The evaporator 14 and expansion device 20 are housed in a forced draft unit 50 (e.g., furnace blower) situated inside the structure S. The unit 50 includes a blower 52 for inducing a draft of return air 54 into the unit. The blower 52 forces the forced air 56 through the evaporator 14 and into duct work 58. As the forced air 56 passes through the evaporator 14, it exchanges heat with the low pressure, low temperature refrigerant in the evaporator coils. Cooled and dehumidified supply air 60 exits the evaporator 14 and is distributed into the structure S through the duct work 58. As the forced air 56 adds heat to the refrigerant in the evaporator 12, the refrigerant transitions to a vapor phase, leaving the evaporator through vapor line 62. The low pressure, low temperature superheated refrigerant in vapor line 62 refrigerant then flows into the compressor 12 to complete the cycle of refrigerant flow through the A/C unit 10.
For purposes of evaluating and testing the unit 10, low side temperature and pressure measurement in the vapor line 62 can be performed at low side port 70. The temperature and pressure of the refrigerant leaving entering the compressor 12 through the vapor line 62 can be measured at the low side port 70. These measurements can be performed, for example, to check unit superheat (suction line temperature minus evaporator saturation temperature). The suction line temperature is measured at low side port 70 and the evaporator saturation temperature is approximated using measured suction line pressure (again taken at low side port 70) along with pressure-temperature charts/look-up tables for the particular type of refrigerant used in the unit 10.
Additionally, for purposes of evaluating and testing the unit 10, high side temperature and pressure measurement can be performed at high side port 72. The temperature and pressure of the refrigerant leaving the condenser 16 through the liquid line 40 can be measured at the high side port 72. These measurements can be performed, for example to check unit sub-cooling (condenser saturation temperature minus liquid line temperature). Liquid line temperature is measured at high side port 72 and condenser saturation temperature is approximated using measured liquid line pressure (again taken at high side port 72) along with pressure-temperature charts/look-up tables for the particular type of refrigerant used in the unit 10.
In a single example, the superheating and sub-cooling data acquired from the unit can be used by a technician to determine whether the unit 10 is in operating normally or is in a state of overcharge or undercharge. If overcharge or undercharge is indicated, the technician can take corrective steps to bring the unit back to normal/optimal operation by adding or removing refrigerant. Such corrective actions, being unit and manufacturer specific, are far too numerous to describe in any detail greater than that which has already been described herein.
The system of the invention is a smart HVAC manifold system for use in the installation, maintenance, and servicing of A/C units, particularly air conditioning and refrigeration units. The system accounts for both the mechanical refrigeration system and also measures changes in the conditioned medium along with electrical characteristics to determine the efficiency of the air conditioning process. The system can perform or assist in performing tasks, such as measuring operating parameters of the unit, measurement conditioning outside of standard conditions, measurement verification, data acquisition (including management, sharing, and reporting), and verifying, quantifying, and troubleshooting unit performance. The system is intended for use by service technicians, maintenance personal, installers, verifiers, operators, mechanics, and any other personnel that may be interested in the operation of A/C units. The scope of the invention and its associated applications will become apparent through this description of the invention and the associated figures.
The smart manifold 102 connects to an A/C unit 106 to measure data (e.g., pressures and temperatures). The unit 106 may, for example, be similar or identical to the unit 10 illustrated in
The smart manifold 102 is a measurement platform for passing data to the smart platform 104. Advantageously, in a smart phone/tablet implementation of the smart platform 104, the smart manifold 102 takes advantage of the large, high resolution screen real estate, the native GPS features, and the native communications and video system. The system 100 uses the smart manifold 102 and smart platform 104 in combination to perform measurements required for commissioning HVAC systems. Additionally, this combination provides computational power to provide an intelligent platform for simple and complex diagnostics of equipment operation and problems. The smart manifold 102, in combination with the smart platform 104 offers a powerful communications platform to allow users to share information with consumers, owners, utilities, equipment manufacturers, and other interested parties and/or service providers. Data can be input into the application using voice to text, text, video, photo, Optical Character Recognition (OCR), on-screen or wireless input devices (e.g., Bluetooth keyboard, Bluetooth headset, mouse), and data streaming from the manifold.
The smart manifold 102 includes sensors that may be wired and/or wireless. Standard core sensor technology will include pressure, and wired temperature sensors (e.g., outdoor air, liquid line, suction line, discharge line). Additional wired or wireless sensors can sense environmental and operating conditions such as wireless temperature & humidity (wet-bulb and dry-bulb; supply air and return air), equipment current, voltage, air velocity, and static pressure. The smart manifold 102 can support the following standard measurements:
The refrigerant manifold 110 is what is referred to in the art as a “three valve manifold.” The manifold 110 could have alternative configurations, such as a two-valve or four-valve configuration. All of these configurations are well known in the field of HVAC service and technology. The manifold includes a low-side port 114 and a low-side handle 116 for opening/closing a valve (not shown) associated with the low-side port. The manifold 110 also includes a high-side port 120 and a high-side handle 122 for opening/closing a valve (not shown) associated with the high-side port. The manifold further includes a refrigerant/vacuum port 124 and a refrigerant/vacuum handle 126 for opening/closing a valve (not shown) associated with the refrigerant/vacuum port. The manifold 110 also can include a low side gauge 162 and a high side gauge 164 for reading those respective pressures directly without use of the smart platform 104. The manifold 110 can be configured such that the gauges 162 and 164 illustrate temperatures in Fahrenheit or Celsius and pressures in PSIA, PSIG, KPa, MPa, or any other desired units. The manifold 110 can include additional ports for measuring pressure, temperature, or other HVAC system operating conditions or environmental conditions.
The low-side port 114 is connected to the low-side line 62 of the A/C unit 10 at the low-side port 70 via one of the connections 108 which, in this instance, includes a low-side hose 130 and a fitting 132 for connecting with the low-side port 70. The high-side port 120 is connected to the high-side line 40 of the A/C unit 10 at the high-side port 72 via one of the connections 108 which, in this instance, includes a high-side hose 134 and a fitting 136 for connecting with the high-side port 72. The refrigerant/vacuum port 124 is connected via a connection 108 to either a refrigerant vessel 140 or a vacuum pump 142, depending on whether refrigerant is to be added or removed from the unit 10. In this instance, the connection 108 includes a refrigerant hose 144 and appropriate fittings (not shown) for connecting with the refrigerant vessel 140 or vacuum pump 142. The low-side handle 116, high-side handle 122, and refrigerant/vacuum handle 126 are operable in a known manner to place the manifold in a condition for measuring high-side and low-side pressures, for adding refrigerant to the unit 10, and for removing refrigerant from the unit 10.
To obtain temperature measurements for the refrigerant in the unit 10, the connections 108 may also include low-side and high-side temperature probes 146 for measuring one or more refrigerant line or air temperatures. The temperature probes 146 may, for example, comprise thermocouple or thermistor sensors with appropriate connectors, such as clamps, for connecting the probes directly to the low-side and high-side refrigerant lines 62 and 40. Although the probes 146 are illustrated in
Referring to
To obtain temperature measurements, the smart manifold 102 includes low-side and high-side temperature transducers 154 and 156 that are operatively connected to the temperature probes 146. Although the temperature transducers 154 and 156 are illustrated as portions of the electronics unit 112, portions of the transducers, or even the entire transducers, could be housed in the refrigerant manifold 110. The temperature transducers 154 and 156 are operative to apply a voltage to the thermocouples of the probes 146 and sense changes in current representative of changes in electrical resistance in the thermocouples due to temperature change. The temperature transducers 154 and 156 convert the currents to temperature indications and provide digital signals representative of the sensed temperatures. Again, those skilled in the art will appreciate that this conversion would include signal processing, such as input buffering, calibration, and analog to digital conversion. These and other such processing functions are well-known and, for simplicity, are intended to be encompassed within the temperature transducers 154 and 156 illustrated in
The smart manifold 102 can be configured to include a number of ports selected to provide the desired measured conditions of the HVAC unit 10. For example, the smart manifold 102 can include four probes for temperature, four ports for pressure, and two ports for vacuum and oil pressure as auxiliary probes. Two of the temperature ports can be used to measure discharge line temperature and the outdoor air temperature.
To obtain relative humidity and temperature measurements of the conditioned medium, the smart manifold 102 can include one or more relative humidity transducers 158 that are operatively connected to one or more humidity/temperature probes 160. Although the relative humidity transducers 158 are illustrated as portions of the electronics unit 112, portions of the transducers, or a device to transmit their readings to the manifold. The relative humidity transducers 158 are operative to sense the relative humidity and temperature in the vicinity of the probes and provide electrical signals representative of the sensed relative humidity and temperature, which can be converted to digital signals representative of the humidity and temperature. Again, those skilled in the art will appreciate that this conversion would include signal processing, such as input buffering, calibration, and analog to digital conversion. These and other such processing functions are well-known and, for simplicity, are intended to be encompassed within the relative humidity and temperature transducers 158 illustrated in
The smart manifold 102 can be adapted to include multiple configurations in which multiple pressure/temperature ports are built into the unit architecture. For example, in one construction, there can be 4 probes for temperature built into the unit as well as 4 ports for pressure, the remaining two for vacuum and oil pressure as auxiliary probes. The other two temperature ports will be to measure discharge line temperature and the outdoor air temperature.
The smart manifold 102 also includes one or more memory modules 170, one or more processing modules 172, and one or more communications modules 174 that are operatively connected to each other, for example, via a communication and data bus 176. As shown in
The smart manifold 102 also includes a power module 168 that provides power for the various components of the electronics unit 112. For simplicity, the power module 168 is illustrated as supplying power via the bus 176, in which case the bus would be of a split design where power and data/communication signals are isolated from each other. The power module 168 could, however, supply power to the various components in any known manner. The power module 168 may include rechargeable batteries, disposable batteries, an external power supply, or a combination of these sources.
The communications modules 174 supports communications between the smart manifold 102 and the smart platform 104 via the smart platform communication module 180. The smart platform communication module 180 can be, for example, Bluetooth, Bluetooth Low Energy (e.g., Bluetooth 4.0, or “Bluetooth Smart”) and/or Wi-Fi communications, since the smart platform 104 (e.g., smart phone, tablet computer, or PC) is typically adapted for either form of wireless communication. Advantageously, as shown in
The network communication module 184 provides communication with the network 250 (see
In one example configuration of the smart manifold 102, the processor 172 may comprise a Freescale Kinetis K20™ microcontroller, which includes a processing unit and non-volatile memory for storing firmware. The communications module 174 may comprise a single-mode Bluetooth Low Energy (BLE) radio, with an optional ZigBee™ radio, and USB On-the-Go (OTG) capabilities. In addition to on-board volatile/non-volatile memory (e.g., VRAM, NVRAM) the memory module 170 may also include an external memory card slot, such as an SD memory card slot. The power module 168 may comprise a rechargeable lithium battery, a charge management integrated controller (IC), and a wakeup button. The smart manifold 102 can include up to four each of the temperature and pressure transducers. The transducers are mounted to a refrigerant manifold 110 and the electronics are housed within an IP rated (e.g., IP-42) enclosure. The microcontroller unit (MCU) processor 172 is the primary processor within the smart manifold 102 and is responsible for performing all measurements.
In this example configuration of the smart manifold 102, the MCU executes instructions from the firmware to perform several functions. The MCU performs analog-to-digital conversions for all attached sensors and performs averaging and signal conditioning for each measurement channel. The MCU transfers all measurement data to the Bluetooth radio module and instructs the Bluetooth module to receive incoming connections and transmit measurement data. Additionally, the MCU can bring the smart manifold 102 into a sleep state when not in use and wakes up the manifold when the button is pressed.
Additionally, the MCU executes instructions from the firmware to acquire and publish data from the pressure sensors and temperature sensors. To do so, the MCU executes firmware instructions to configure each analog-to-digital conversion (ADC) module to acquire a digital sample from each sensor channel, advance to the next channel after each acquisition. Each sample is converted to a floating-point value, incorporating minimum/maximum limits and calibration data in the conversion. The acquired sample is stored in a rotating buffer containing the last N samples. An averaging function is performed over the last N samples to produce a single, stable measurement value for each channel. This value is placed in the data store.
Additionally, in this example, the smart manifold 102 provides all measurement data to a remote system (e.g. smartphone) via the Bluetooth communication. To do this, the MCU executes firmware instructions to convey the data to the BLE module of the communications module 174 for transmission. The BLE module runs firmware built by a special tool provided by the module manufacturer. The BLE firmware implements a GATT (Generic Attribute) profile specific to the smart HVAC manifold system 100, which allows a BLE host to retrieve each measurement from the smart manifold 102. To configure the firmware, the developer edits XML files describing the GATT profile for the application and the hardware configuration of the module, then runs the tool which generates the firmware image. The GATT attribute data is transferred via a universal asynchronous receiver/transmitter (UART) between the two devices using a simple serial protocol defined by the module manufacturer. The MCU does not need to manage any of the Bluetooth-specific functions; it only provides the measurement data to the BLE module. The BLE module manages all Bluetooth-specific functions and notifies the MCU when certain events occur, such as connects, disconnects, and reboots.
In this example, the smart manifold 102 employs a low power management strategy in which the electronics unit 112 is powered by an internal rechargeable lithium battery. The battery is recharged through the micro-USB port and requires no MCU intervention. The MCU needs to keep itself and the Bluetooth radio in a low-power state when the device is not being used, to prevent battery drain. The MCU also needs to wake up when either the pushbutton is pressed or the Bluetooth radio wakes up from an over-the-air request. When woken up, the MCU will stay awake for as long as an active Bluetooth connection is maintained. After the connection is closed, the MCU will stay awake for a short amount of time and then go to sleep. The MCU can sleep the radio by software command and wake it up via general-purpose I/O (GPIO).
The smart platform 104 can include a custom mobile application that can communicate with the smart manifold 102 for the purposes of data acquisition and analysis, as well as device calibration and other interactive functions. The communication between the smart manifold 102 and smart platform 104 can be performed via Bluetooth Low Energy (Bluetooth 4.0, or “Bluetooth Smart”) radio. Bluetooth Low Energy (BLE) radio. BLE is a new Bluetooth standard for low-power or battery-operated devices which allows rapid exchange of data using a connectionless protocol, eliminating the time required to re-establish a connection between two devices. BLE functionality is implemented in many newer smartphones and tablets such as the iPhone 4S™, iPhone 5™, iPad™ 3rd gen (Retina), Nexus 7™, Galaxy S III™, and Droid Razr™. While a smart phone with a touch screen interface is described herein, the smart platform 104 could have an alternative form, such as a tablet device, a tablet PC, or a portable laptop PC and could use alternative interface, such as a keyboard, mouse, track pointer, voice recognition, gestures, etc.
The smart manifold application (“manifold app”) 200 is installed on the smart platform 104 (see
An example of an initial screen 210 of the manifold app 200 is illustrated in
A primary function of the manifold app 200 can be to discover an active device through Bluetooth. When the user presses the “Discover” button in the instruction area 218 on the main screen 210, the app will put up a “Discovering . . . ” dialog for a few seconds, then display a list of any discovered devices. This is shown in
Once the manifold app 200 has connected to a Device, the app will then retrieve data from the Device and display it on the data screen. An example of a data screen 220 is illustrated in
The manifold app 200 can record received data to the internal memory 204 of the smart platform 104. Files can be named according to Device ID and time of recording. The files can be retrieved from the smart platform 104 and transmitted via any means available to the smart platform, such as a wireless cellular communications, WiFi communications, Bluetooth communications, or satellite communications.
A primary function of the smart HVAC manifold system 100 is to allow standard service procedures and to perform the basic calculations required to properly charge (add or remove refrigerant), determine capacity, Energy Efficiency Ratio and proper operation as specified by the A/C system equipment manufacturer and heat pumps using standardized charging charts/calculations for fixed type metering devices and target subcooling for thermal expansion valve (TXV) systems.
To accomplish this task, the smart HVAC manifold system 100 includes a perfect charge module that looks at target output (BTUh), electrical current and refrigerant charge characteristics to determine optimum refrigerant charge. As refrigerant is added to an A/C system, the cooling output and the EER (BTUs removed/power (watts) consumed) will increase until the charge is as the optimum level. If refrigerant is added beyond the optimum level, the refrigerant will back up in the condenser causing a decrease in the EER and a decrease in cooling output in fixed orifice systems due to an increase in the suction pressure and a reduction in condenser space and increase in discharge pressure. In fixed orifice systems, target superheat will be monitored along with output to determine the optimal operation. This module will require the use of external wet bulb and dry bulb thermometers, one or more current clamps, and airflow inputs, either from the Smart manifold or through user input.
The smart HVAC manifold system 100 can also include a troubleshooting module including a mode or algorithm that allows users to input information about the type of system and its components and, based on this information, will apply standardized troubleshooting algorithm(s) to help diagnose typical HVAC problems. This mode also includes basic service advice on fault remedies and tips to properly identifying problems. Examples might include considerations when installing a new TXV: bulb mounting, orientation, manufacturer nomenclature, and applications. Typical problems that can be encountered when troubleshooting can include:
The smart HVAC manifold system 100 can also include a compressor diagnostics mode that reads motor current from the common, start and run windings via optional probes that attach to the smart manifold 102. These readings are used to diagnose typical compressor problems.
The smart HVAC manifold system 100 can perform a variety of calculations related to the operation and maintenance of the A/C unit 106. All standard calculations will include information about the standard calculations (e.g., how calculated) and their typical ranges. This information can be accessed via the smart platform 104 and can be transmitted via the network 250 using one of the various modes of transmission employed by the smart platform. The system will allow for US customary or metric (SI) units of measure. The following standard calculations can be performed:
Additionally, capacity calculations can be derived by measurements of mass flow rate of the conditioned medium at the evaporator coil and changes in enthalpy of the conditioned medium (air). The total heat added or removed can be determined using (preferably) a non-density dependent method of airflow measurement, or a density dependent method that is corrected by the apparatus, and a dry bulb and humidity sensor for the refrigerated or heated medium.
When using any of the air formulas it is important to understand how to correct for changes in the air density if the air being measured is not standard air. The air constants apply to standard air at 70° F. and 14.7 Pisa, (29.92″ hg.) If air being measured is outside of these parameters, it may require that the constant be recalculated. For most situations the standard air formulas can be used, but if precise measurements are desired, adjustments to the constants should be made. Remember, fans are doing work; they are moving in reality pounds of air. The amount of air they will move in CFM remains constant with a variable mass flow rate, so the cubic feet of air they will move over any given time period will remain the same. The difference is in the density of the air or the number or the pounds per cubic foot. This is important because coil selection software calculates required coil capacities based upon pounds per hour (lb/hr) of air passing through the coil, not CFM.
The constant 4.5 is used to convert CFM to lbs/hr:
4.5=(60 min/hr+13.33) or (60 min×0.075 lbs/cu ft), where:
Air Density (lb/cf)=1.325×Bp/Tabs, where:
Example: 1.325×29.92/(70° F.+460° F.)=0.0748−0.075 lb/cu ft.
This is how standard air density is calculated.
If you were measuring air coming out of a furnace, and the air was 154° F. the air density would change as follows:
1.325×29.92/(154° F.+460° F.)=0.0645
If heated air were used in this formula, the constant would be:
(60 min×0.0645 lbs/cu ft)=3.87 instead of 4.5 used for standard air.
The constant used in the sensible heat formula 1.08 is used to convert CFM to lbs/hr and factor in 0.24 the specific heat of standard air (BTU/lb/° F.), where:
1.08=(0.24×60)/13.33 or 0.24×4.5
4.5=60 min/hr+13.33, or (60 min×0.075 lbs/cu ft)
0.68=(60/13.33)×(1060/7000) or 4.5×(1060/7000); and where:
The smart HVAC manifold system 100 can acquire real time data and use that data to perform performance calculations. Since HVAC systems are dynamic and conditions (e.g., load, ambient, and equipment output) are constantly changing, real time data acquisition of multiple points of data is necessary to accurately quantify performance and evaluate operation. Technicians capturing data manually are restricted by the time required to gather and interpret the measurements, record data and perform calculations before the load changes. Often systems are tested at a load condition less than full load, so conditions change faster than data can be obtained through traditional means. The system 100 can also verify measured data using algorithms that rule out data gaming and suspect or impossible measurements. The smart HVAC manifold system 100 can also perform measurement conditioning using GPS data and weather conditions available from local weather data (either automatically or via user input, as required) to apply corrections for non-standard conditions that might affect sensor accuracy or calculated accuracy if non-standard conditions were not considered. All of this can be performed in real time.
The implementation of the smart device to the smart platform 104 in the smart HVAC manifold system 100 yields many features and advantages that owe to the special functionality that current smart phone/device technology employs. Referring to
When changes are made during the servicing of a refrigeration system, particularly when refrigerant is added or removed to obtain the correct charge, there is an impact on system performance capacity that affects the overall operation. Many system variables and indicators of correct operation are affected and take time to stabilize. A technician that is rushed to complete service or unaware of all of the variables that impact performance may not wait long enough or could wait too long for the system to reach study state conditions before evaluating the impact on the changes that have been made. If these changes are made to quickly there is a high probability of overcharging or undercharging the system leaving it with substandard operation or driving the technician to undo changes that were made. If the technician waits too long there are lost labor costs. Because of real time data acquisition, the smart HVAC manifold system 100 can assess system changes over time and indicate when a steady state condition has been achieved and the system performance then be quantified, thus saving valuable repair time and money.
One advantage of the smart HVAC manifold system 100 realized through the implementation of the smart platform 104 is that manufacturer data 272 can be accessed via the network 250 and the A/C unit 106 can be tagged and identified, operating ranges and other pertinent information can be stored, and calculations/tables can be adjusted so that the unit is tuned in accordance with manufacturer specifications. The manufacturer data 272 can also include equipment specific troubleshooting data that can be used to identify problems with a specific A/C unit 106 based on manufacturer recommendations.
Another advantage of the smart HVAC manifold system 100 realized through the implementation of the smart platform 104 is that the smart phone built-in camera functions of the smart platform 104 can be utilized to scan equipment label data 280, such as bar codes or QR codes, to obtain identifying data for the A/C unit 106. This data can be used to obtain more detailed manufacturer data 272 for the A/C unit 106 via the network 250. Additionally, the system can allow users to tie photos to the pinned job site via the GPS module. This can allow the user to include tagged photos in reports to illustrate identified problem conditions, such as plugged coils, bad or misaligned or incorrectly tensioned belts, electrical failures, etc. Photos can also be used for equipment ID and tied together to show locations of thermostats, outdoor air controls or other remote sensors that might be tied to a unit. All photos can be location tagged via GPS for easier location by subsequent service technicians. Photos can also be tagged with unit settings and a historical data regarding the unit.
The multi-platform capabilities of the smart HVAC system 100 allows for customized applications (or apps) that will allow manufacturers to collect information about the operation of the system and to see initial commissioning results for warranty purposes. Applications may be customized with a database of unit performance or go to a remote look-up table to gather performance about the equipment (e.g., the Air-conditioning, Heating and Refrigeration Institute or AHRI directory of certified product performance, see http://www.ahridirectory.org/ahridirectory/pages/home.aspx).
Using the data gathered by the system 100, graphic trending allows user to see operating characteristics of the A/C unit 10 operation and/or service over time. These operating characteristics can include:
Another advantage of the smart HVAC manifold system 100 realized through the implementation of the smart platform 104 is that person-to-person communications 274 can be established over the network 250 via the cellular network connection 252 or the WiFi network connection 254. Additionally or alternatively, the communications 274 can be established directly with the smart platform 104 establishing a direct cellular network connection 276. Communication can be established from within the manifold app 200 or can be established with the app running in the background. The communications 274 may include text messaging, voice over internet protocol VOIP, video conferencing (2-way), email, and cellular voice and data. The communications can be used for technical support, training, and for communicating with others employing the smart HVAC manifold system 100.
These advanced communications features may enable a pay per use or a subscription service that gives users access to a group of seasoned professionals to help trouble shoot equipment problems. The service is a forum based product that has residential, commercial, industrial, and possible dealer only (eg. Trane, Carrier, Lennox) boards for users to ask questions. The service can be a moderated user community forum that is a subscription service that allows users to help each other solve problems in the field. Answers to user's questions are peer rated on a scoring system (e.g., 1 to 5 stars) that rates the quality of the answer. These professionals will be able to view the users information in real-time via their smart platform. If there are multiple answers to the questions users can sort answers by the rating of the person that answered the question. This group of professionals answering the questions can be grown from the top rated HVAC members and retired HVAC professionals that meet pre-established requirements to provide quality phone support. Support can be done via Skype®, Apple FaceTime®, text (SMS) messaging, phone or other similar medium. The service provides advanced support to technicians to provide solutions to problems that are not easily identifiable due to technician experience level or problem complexity. Service could be made available around the clock.
Serving as the go-between for the local smart manifold 102, the web/cloud-based network 250, and the GPS location data 260 allows the smart platform 104 to facilitate combining the data to provide several advantageous features. Since the smart platform 104 communicates locally with the smart manifold 102 via Bluetooth, the GPS location data 260 can be used to associate the manifold with a geographic location. The system can thus utilize geo-tagging/time tagging for identification and recordation purposes. Additionally, since all of these functions converge at the manifold app 200 on the smart platform 104, any data acquired by the app or entered into the app can be time-stamped and recorded in real time, and can be used, e.g., for purposes of reporting, auditing, and long term trending.
The smart platform based GPS allows the technician to pinpoint the location of where the system is serviced via an online mapping service (e.g., Google maps). The GPS will show the approximate location of the technician relative to the equipment (e.g., within about 5-10 meters accuracy with full view to the sky) and allow the technician to drop a pin at the exact location if needed. The address will be automatically imported from the GPS location. When the pin is selected on the map, information about the unit including model and serial numbers, last date of service, servicing technician, unit service history, past performance will be available (i.e., if the HVAC smart manifold system 100 was utilized in commissioning or previous service of the unit). Also available will be a photo of the model and serial number tag to verify unit is the exact unit identified by the location marker.
Over time, a map of A/C unit 106 installations identified by the smart HVAC manifold system 100 can be developed and used for multiple purposes, such as producing a savings calculator for equipment replacement purposes, or producing a calculator for equipment repair that estimates payback periods. Such a map could also be used to anticipate electric utility demand by geographic location.
Knowing the GPS location data 260, the manifold app 200 can access location data, such as weather and climate data, and time-stamp and associate that data with operations (e.g., tune-ups) performed on the A/C unit 106 at a site specific location. Additionally, the weather and altitude data can be used to make adjustments to calculations, for example, to air density based on the barometric pressure and altitude at the geographic location.
Example configurations of the smart HVAC manifold system 100 are illustrated and described in
The manifold app 200 also can implement a verification in field (“VIF”) function. The manifold app 200 can transmit data from the smart manifold 102 to a platform where the data can be stored, used to generate reports, and used to perform analytics. This transmission can, for example, be through the internet connection provided by the smart platform 104. The platform to which the verified data can be transmitted can, for example, be a remote server, a cloud based storage platform, a remote computer, or a combination of these platforms. Transmission of the verified data in this manner provides added security in that the VIF function ensures that the data has not been subject to any manipulation or modification by field personnel. This VIF function of the manifold app 200 can help ensure that the data measured by the smart manifold 102 is accurately submitted by the smart platform 104. The VIF function thus verifies that the data transmitted by the smart platform accurately reflects the measurements taken by the smart manifold 102. In this manner, the end user/customer can be ensured that the reports, analytics, and any required services suggested by the measured data is accurate, not manipulated (or gamed), of financial grade, and honest.
The HVAC manifold system 100 has the unique ability to collect information from a large number of sensors. For instance, in one implementation, in addition to the pressure sensors that measure pressures in the manifold, the system 100 can collect data from 4 wired inputs, 12 wireless direct inputs, and up to 36 indirect wireless inputs. The VIF function of the manifold app 200 implemented by the system 100 can monitor whether any of the measured data has been changed or otherwise manipulated from the values measured by the sensors. The VIF function can tag unchanged, non-manipulated data as “verified” data, and can tag changed or manipulated data as “non-verified” data.
The VIF function of the manifold app 200 can be configured to prevent the user from changing or otherwise manipulating any of the data collected by any of the sensors. This can be a configurable feature that, for example, is implemented as part of a user profile. Configuration of the VIF function can be security cleared so that only the appropriate personnel can modify data. In any event, however, the VIF function can tag any and all data as “verified” or “non-verified.” Verified data can be displayed, e.g., in printed reports and web pages, etc., with an identifying mark, such as a checkmark, to indicate its verified status. Non-verified data can also be displayed with an identifying mark, such as an “x,” or simply by the absence of a checkmark.
The availability of verified data can play an important role in effective use, maintenance, and administration of HVAC equipment. An essential element to cooling equipment is, of course, refrigerant. In order to operate properly, cooling equipment must be properly charged with refrigerant. Determining the proper charge requires performing calculations that use the various pressure and temperature measurements measured directly from the cooling equipment. It is estimated that as much as 70% of the cooling equipment installed in the U.S. is improperly charged.
This improper charging can be attributed to a variety of sources. Imprecise measurements taken by technicians using analog gauges, and performing manual calculations using those measurements can produce errors that result in improper charges. Inexperienced technicians can make mistakes or can lack the expertise to properly charge systems even if the calculations are performed correctly. Unscrupulous technicians can profit from reduced material costs by purposely undercharging cooling systems.
The VIF function implemented by the manifold app 200 can provide independent third party verification of data measured by the smart manifold 102, such as equipment pressures and temperatures, that can be used to perform a variety of functions, such as monitoring performance, scheduling maintenance, and controlling costs. This information is valuable to a variety of personnel, such as equipment owners, equipment manufacturers (who, for example, may offer warranties or wish to monitor performance of their installed equipment), and contractors who want to verify proper installation and reduce call-backs.
The VIF function implemented in the manifold app 200 of the smart HVAC manifold system 100 can provide verification that equipment is operating efficiently. The ability to tag data as verified combined with the ability to store the information remotely, provides a unique opportunity to provide value in cloud-based services. Differentiating between verified and non-verified data allows for the generation of reports and the performance of system analytics with an enhance degree of confidence and credibility. This confidence/credibility in the data and performance analytics will be increased by the pieces of information that are verified, as these characteristics improve along with the degree of verification in the data.
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From the above description of the invention, those skilled in the art will perceive improvements, changes and modifications. Such improvements, changes and modifications within the skill of the art are intended to be covered by the appended claims.
| Number | Date | Country | |
|---|---|---|---|
| 61978462 | Apr 2014 | US |
