Patent Application
20130036756
The embodiments described herein relate generally to controlling a motor, and more specifically, to measuring an air temperature and controlling the motor based at least partially on the measured air temperature.
Heating, ventilation, and air conditioning (HVAC) systems typically include electric motors. For example, a typical HVAC system includes a condenser unit positioned exterior to a structure being heated/cooled by the HVAC system that includes a compressor, a compressor motor, a condensing coil, and a condenser fan motor that drives a condenser fan. Typically, the condenser fan motor runs at a fixed speed.
The increasing cost of energy, for example, the electricity used to power an HVAC system, and heightened environmental concerns, have increased the demand for more efficient HVAC systems. The Air Conditioning, Heating and Refrigeration Institute defines the Seasonal Energy Efficiency Ratio (SEER) in its standard ARI 210/240, titled Performance Rating of Unitary Air-Conditioning and Air-Source Heat Pump Equipment. The SEER rating of an HVAC system is the cooling output in British thermal unit (Btu) during a typical cooling-season divided by the total electric energy input in watt-hours during the same period. The higher the SEER rating, the more energy efficient the system is. However, increasing the efficiency of an HVAC system typically increases the cost of the HVAC system.
In one aspect, an electric motor configured to drive an air moving device included within a heating, ventilation, and air conditioning (HVAC) system is provided. The air moving device is configured to draw air through a condensing coil of the HVAC system from a first side of the condensing coil to a second side of the condensing coil. The motor includes a temperature sensor configured to measure an exhaust air temperature at the second side of the condensing coil and to generate a temperature signal that includes measured temperature information. The motor also includes a controller communicatively coupled to the temperature sensor and configured to receive the temperature signal and to control operation of the motor based at least partially on the temperature signal.
In another aspect, a heating, ventilation, and air conditioning (HVAC) system is provided. The HVAC system includes a condensing coil and an air moving device configured to draw air from a first side of the condensing coil to a second side of the condensing coil. The HVAC system also includes a temperature sensor configured to measure an exhaust air temperature at the second side of the condensing coil and to generate a temperature signal that includes measured temperature information. The HVAC system also includes an electric motor including a controller and configured to drive the air moving device in response to control signals from the controller. The controller is configured to receive the temperature signal and to control operation of the electric motor based at least partially on the temperature signal.
In yet another aspect, a method for controlling a fan motor configured to draw air through a condensing coil of a heating, ventilation, and air conditioning (HVAC) system from a first side of the condensing coil to a second side of the condensing coil is provided. The method includes measuring an exhaust air temperature at the second side of the condensing coil and controlling a speed of rotation of the fan motor based at least partially on the measured temperature.
The methods and systems described herein facilitate increasing an energy efficiency of an HVAC system. The overall energy usage of the HVAC system is reduced by reducing an operating speed of the condenser fan motor when operating the condenser fan motor at a higher speed would not benefit cooling/heating.
Technical effects of the methods, systems, and computer-readable media described herein include at least one of: (a) measuring an exhaust air temperature at the second side of the condensing coil; and (b) controlling a speed of rotation of the fan motor based at least partially on the measured temperature.
In the exemplary embodiment, motor 48 includes a housing 54 and a temperature sensor 56, for example, a temperature transducer, coupled to an exterior 58 of housing 54. Although described as coupled to housing 54, temperature sensor 56 may be coupled to a motor mounting 59, coupled to wiring (not shown in
In the exemplary embodiment, fan motor 48 includes a motor controller 60 for controlling operation of fan motor 48. Controller 60 may include a processor 62 and a memory device 64. Controller 60 may also include a communication interface 66 that allows a user to communicate with controller 60, for example, to select and/or edit data stored within memory device 64. Communication interface 66 may include, but is not limited to, a serial communication adapter, a parallel communication adapter, and/or a plurality of selectable taps.
In the exemplary embodiment, controller 60 is communicatively coupled to temperature sensor 56 and is configured to receive a temperature signal corresponding to a measured temperature from temperature sensor 56. In the exemplary embodiment, motor 48 is a variable speed motor and controller 60 provides motor 48 with a control signal corresponding to a desired speed of operation for motor 48. Controller 60 determines the desired speed of operation based at least partially on the measured temperature from temperature sensor 56. The exhaust air temperature is an indicator of the loading on compressor 40. The load on compressor 40 varies based on, for example, but not limited to, an ambient air temperature exterior to condenser unit 32 and contaminants present in and/or on condensing coil 42 that restrict airflow through condensing coil 42. Varying the speed of rotation of motor 48 increases an overall efficiency of HVAC system 10 by allowing motor 48 to run at a lower speed, and therefore consume less energy, when the measured temperature allows. The reduction in energy consumption by motor 48 increases a SEER rating of HVAC system 10.
In some embodiments, HVAC system 10 includes a system controller 68. System controller 68 is configured to control operation of, for example, an indoor blower 70, compressor 40, and other components within HVAC system 10. In an alternative embodiment, system controller 68 is communicatively coupled to temperature sensor 56 and is configured to receive a temperature signal corresponding to a measured temperature from temperature sensor 56. In the alternative embodiment, system controller 68 determines a desired speed of operation for fan motor 48 based at least partially on the measured temperature from temperature sensor 56 and provides fan motor 48 with a control signal corresponding to the desired speed of rotation.
More specifically, when HVAC system 10 is in a cooling mode (e.g., an air conditioning mode) and the outlet air temperature measured by sensor 56 is high, controller 60 operates motor 48 at a first speed, providing a first level of airflow over condensing coil 42. When the outlet air temperature measured by sensor 56 is lower, controller 60 operates motor 48 at a second speed, wherein the second speed is slower than the first speed. Operating motor 48 at the second speed provides a second level of airflow over condensing coil 42, i.e., a lower level of airflow over condensing coil 42. Operating motor 48 at the second speed when the outlet air temperature allows does not adversely affect the cooling provided by HVAC system 10, while creating an overall energy savings.
Conversely, when HVAC system 10 is in a heating mode (e.g., a heat pump mode) and the outlet air temperature measured by sensor 56 is low, controller 60 operates motor 48 at a first speed, providing a first level of airflow over condensing coil 42. When the outlet air temperature measured by sensor 56 is higher, controller 60 operates motor 48 at a second speed, wherein the second speed is slower than the first speed. Operating motor 48 at the second speed provides a second, lower level of airflow over condensing coil 42. Operating motor 48 at the second speed reduces an energy usage of motor 48.
In the example shown in
In cooling mode, fan motor 48 is operated at a constant rotational speed 82 when exhaust air temperature 84 is above a third temperature 98, for example, 110 degrees Fahrenheit. At exhaust air temperatures below third temperature 98, and above a fourth temperature 100, the rotational speed at which fan motor 48 is operated is reduced. More specifically, the closer the exhaust air temperature is to the indoor temperature HVAC system 10 is set to provide, the lower the load is on compressor 40. Operating fan motor 48 at a lower rotational speed when the load on compressor 40 allows for reduced airflow across condensing coil 42 reduces energy consumption by fan motor 48 and therefore increases the energy efficiency of HVAC system 10.
In the example shown in
In the exemplary embodiment, operating instructions are stored within memory device 64 (shown in
In the exemplary embodiment, controller 60 receives a mode selection signal 116 from, for example only, system controller 68. Controller 60 generates a motor speed demand 118 based at least partially on first temperature signal 110, second temperature signal 114, and mode selection signal 116. For example, based on mode selection signal 116, controller 60 may select a specific motor speed vs. temperature curve, for example, curve 80 (shown in
Method 122 may also include storing 128 an algorithm configured to increase an overall energy efficiency of HVAC system 10, compared to fixed-speed operation of fan motor 48, by determining a speed at which to rotate fan motor 48 based at least partially on the measured temperature. In the exemplary embodiment, the algorithm is stored in a motor controller, for example, controller 60 (shown in
Described herein are exemplary methods and systems for controlling a fan motor included within an HVAC system. More specifically, an electric motor is described herein that is equipped with electronics to vary the speed of a condenser/heat pump evaporator fan responsive to the condenser/heat pump evaporator outlet air temperatures so as to increase the efficiency of the HVAC system when compared to fixed-speed operation of the condenser/heat pump evaporator motor. The methods and systems described herein facilitate reducing the overall energy usage of the HVAC system by reducing an operating speed of the condenser fan motor when operating the condenser fan motor at a higher speed would not benefit cooling/heating. The methods and systems described herein determine when the loading on the compressor is at a low enough level that a reduced airflow across the condensing coils will provide adequate heat transfer by the condensing coils.
The methods and systems described herein facilitate efficient and economical operation of an HVAC system. Exemplary embodiments of methods and systems are described and/or illustrated herein in detail. The methods and systems are not limited to the specific embodiments described herein, but rather, components of each system, as well as steps of each method, may be utilized independently and separately from other components and steps described herein. Each component, and each method step, can also be used in combination with other components and/or method steps.
When introducing elements/components/etc. of the methods and apparatus described and/or illustrated herein, the articles “a”, “an”, “the”, and “said” are intended to mean that there are one or more of the element(s)/component(s)/etc. The terms “comprising”, “including”, and “having” are intended to be inclusive and mean that there may be additional element(s)/component(s)/etc. other than the listed element(s)/component(s)/etc.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.
