Refrigeration fan motor controller for ECM

Abstract

A control system for use with refrigeration devices utilizes a refrigeration evaporator fan speed controller, at least one remote current sensor, temperature sensor, or compressor mechanical/electrical contact sensor, and a sensing relay to determine when the compressor in a refrigeration system is operating. When the current, temperature, or electrical contact sensor detects that the compressor is not operating, the refrigeration evaporator fan speed is reduced to run at a lower speed than when the compressor is operating.

Description

RELATED APPLICATIONS

This application claims the benefit United States Provisional Applications for patent Ser. No. 11/212,435 and filed and Ser. No. 60/693,810, filed Jun. 25, 2005, incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to energy savings for various products, and more particularly to an apparatus and method for controlling a fan motor to achieve such savings in a refrigeration system.

2. General Background and State of the Art

Current Sensing Background

Currently, the marketplace does not offer an evaporator fan control system for a refrigeration system that can be used outside the refrigerated chamber to control evaporator fan motor speeds inside the refrigerated chamber. The present invention is an improved apparatus and method requiring no retrofit rewiring inside the refrigerated chamber. All wiring can be accomplished at a circuit breaker panel.

Refrigeration systems which are in operation today are not quite as efficient as they could be. One of the problems associated with most known refrigeration systems is that the refrigeration fans are operating continuously at high speeds most of the time, regardless of whether the compressor is on or whether the temperature inside the refrigerated chamber requires the fans to operate at high speeds. Evaporator fans need only be on high speed when the compressor is on. However, maintaining fans continuously at high speed, as is customary, wastes electrical energy, adds undesirable heat into the cooler from the fan motor typically being inside the cooler, and increases overall costs and maintenance requirements for the cooler system.

The invention disclosed herein suggests and delineates at least three methods of determining when the compressor is on, i.e. when the cooler or cooling volume needs further cooling, and therefore when the evaporator fan need be running at high speed; i.e. when the cooler is at a desired temperature, the compressor is off at which time the fan motor need only be running at a low speed to save electrical energy and decrease fan motor heat.

A first method utilizes a compressor current sensing device that regulates the fan speed; i.e. when current flows to the compressor, the compressor must be on and therefore direction must be given for a high fan motor speed.

A second method senses a delta temperature (temperature change) differential across the evaporator cooling coil to regulate the fan speed; i.e. when the compressor is on air flowing into the evaporator coil will be a bit warmer than air exiting said coil.

A third method utilizes a sensor that determines when elements in the current switching device to the compressor make contact, thereby closing the circuit and enabling current flow to the compressor. In each of the foregoing processes, a thermostat typicality in the cooler unit indicates when the compressor is to be kicked on when a cooling effect is needed and turned off when the cooler unit is at a desired temperature.

Again, it can be observed that when the compressor is not operating, there will be no electrical current flow in the refrigeration system wiring. Whereas, the existence of electrical current flow in the refrigeration system wiring indicates that the compressor is operating, meaning that it will be necessary to keep the fans at high speed.

A typical problem with present cooling systems is that under normal system operation with no fan controller, when the refrigerated chamber reaches pre-set temperature setting, the fans remain running when the compressor is off as well, and these fans generate heat. The heat generated by these fans increases the heat load in the refrigerated chamber, which brings the compressor back on, which in turn causes an unnecessary waste in electrical energy.

When designing a refrigerated chamber, the heat generated by the evaporator fans must be taken into consideration when sizing the system. The compressor must take away the additional heat produced when fans are running unnecessarily. The energy cost is paid twice because of the unnecessary running of fans when the compressor is off. This raises the temperature in the refrigeration chamber and shortens the off-cycle of the compressor.

There are devices which have attempted to reduce the energy consumption of refrigeration systems. U.S. Pat. Nos. 5,488,835 and 5,797,276, both to Howenstine et al., disclose such devices. The drawback to these devices is the fact that the technology used is somewhat outdated and more cumbersome than the present invention. U.S. Pat. No. 6,397,612 to Kernkamp et al., discloses a device that uses a current sensor in order to determine whether the refrigeration system fans should be shifted to lower speeds. The drawback to the Kenkamp et al. invention is that the current sensor is dependent on a solenoid valve as well as a thermostat, which many existing refrigeration systems do not use.

Another problem with known systems and methods is that most such systems are dependent upon the temperature of the actual coil and warm copper pipe running to it to sense the temperature.

Another problem with other prior art devices and methods such as that disclosed in the '835 patent is that their operation is predicated upon a thermostat and measuring the temperature differential across an expansion valve. Such control systems are not adaptable for a freezer system because systems such as that disclosed in the '835 patent are operated mainly above 28 degrees Fahrenheit, whereas most freezer systems are operational in the temperature range of minus 10 to minus 25 degrees Fahrenheit. The present invention is an improvement over prior art systems because it can be adapted for use with a freezer system, as it does not require the use of a thermostat.

It is to be understood that the term “prior art” as used herein or in any statement made by or on behalf of applicants means only that any document or thing referred to as prior art bears, directly or inferentially, a date which is earlier than the effective filing date hereof. No representation or admission is made that any of the above-listed documents is part of the prior art, or that an exhaustive search has been made, or that no more pertinent information exists.

Temperature Sensing Background

Currently, the marketplace does not offer an evaporator fan controller specifically designed for freezers but can be used with medium temperature systems utilizing a temperature sensor to regulate fan speed. Freezer and/or other medium temperature refrigeration systems which are in operation today are not quite as efficient as they can be. One of the problems which inhere with most refrigeration systems is the fact the refrigeration fans are operating at high speeds most of the time irregardless of whether the temperature inside requires the fans to be at high speeds. In addition, maintaining fans at high speeds requires the expenditure of great amounts of energy which is very costly.

It will be pointed out here that not temperature differential indicates that the compressor is not running. Whereas the existence of a temperature differential indicates that the compressor is on, means that it will be necessary to keep the fans at high speed.

Another problem with the current systems is that under normal system operation with no fan controller when the box reaches pre-set temperature input the fans remain running when the compressor is off and these fans generate approximately 200 Watts of heat per fan when using shaded pole motors. And the heat generated by these fans increases the heat load in the box which brings the compressor back on.

When designing a box the heat of the fans must be taken into consideration when sizing the system. Compressor must take away the additional heat produced when fans are unnecessarily running. The energy cost is paid twice because of the unnecessary running of fans when compressor is off. The compressor must take back the heat generated when it was off. This thereby shortens the off-cycle of the compressor.

There are patents which have attempted to reduce the energy expenditure of refrigeration systems. U.S. Pat. Nos. 5,488,835 and 5,797,276 pertain to the present invention. The drawback to these inventions is the fact that the technology used is somewhat outdated and more cumbersome than the present invention. U.S. Pat. No. 6,397,612 uses a current sensor in order to determine whether the refrigeration system fans should be shifted to lower speeds. The drawback to this invention is the fact that the current sensor is dependent on a solenoid valve as well as a thermostat which many systems do not use.

Another problem with the other inventions is that most systems are dependent on the temperature of the actual coil and warm copper pipe running to it to sense the temperature.

Another problem with the other invention, U.S. Pat. No. 5,488,835 is that its use predicated upon a thermostat and the temperature across the expansion valve. This system is not adaptable for a freezer because this system is operated mainly above 28 degrees Fahrenheit whereas most freezers are operational between the temperature range of: minus (−) 10 to minus (−) 20 Degrees Fahrenheit. The present invention is an improvement upon this patent because it does not require the use of a thermostat nor does it require an expansion valve. Accordingly, there is no prior art which is specifically adapted for and designed for use with freezers. The prior art deals exclusively with refrigeration systems of medium-range temperatures.

It is to be understood that the term “prior art” as used herein or in any statement made by or on behalf of applicants means only that any document or thing referred to as prior art bears, directly or inferentially, a date which is earlier than the effective filing date hereof. No representation or admission is made that any of the above-listed documents is part of the prior art, or that an exhaustive search has been made, or that no more pertinent information exists.

Electrical Contact Sensing Background

Simply stated if no power is applied to the compressor, the compressor cannot be on. Therefor, a remote, external contact sensing element is provided to determine when the compressor is on. When electrical contact is made by mechanical or other means to the compressor input, then the fan motor will be commanded to run at high speed. When no contact is made, the compressor is obviously not running, and correspondingly the fan motor will be set a low speed.

SUMMARY OF THE INVENTION

The compressor is the main energy in all freezer and/or refrigeration systems. The main focus of the present invention is to keep the system compressor off for as long as possible to achieve maximum energy savings. This savings can be achieved by reducing the heat load in the refrigerated chamber. By reducing the evaporator fan speed when the compressor is off, it is possible to achieve up to 85% energy savings and head load from the fans by not adding the heat of the fans to the refrigerated chamber.

Also, by reducing the head load in the refrigerated chamber, the temperature control portion of the refrigeration system stays off for longer periods, whether it utilizes a thermostat or other control means.

Another main objective of the present invention is to provide a control system where no thermostat or solenoid valve exists within the refrigerated chamber, but the temperature is controlled by a pressure device located outside in the condensing unit. Likewise, it is known in the art that some systems control the temperature through a remote-monitoring system by a computer.

Another object of the present invention is to ensure that the control system is not predicated upon the use of a thermostat or a specific metering device. The problem with other inventions such as those disclosed in Howenstine, et al., is that their operation is predicated upon a thermostat and measurement of the temperature differential across the expansion valve. The present invention is an improvement upon these devices because it does not require the use of a thermostat, nor does it require the temperature differential across the expansion valve. The present invention does not require the use of a thermostat because the system electric current is measured at the circuit breaker panel. Whereas Howenstine et al relies upon measuring the temperature differential across the expansion valve, the present invention measures the electrical current flow. This feature may also be adaptable for any range temperature units as well.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, aspects and disadvantages will be better understood from the following detailed description of the preferred embodiments of the invention with reference to the drawings in which:

FIG. 1C illustrates an exemplary embodiment according to the present invention; and

FIG. 2C illustrates a flow diagram of the control logic of an exemplary embodiment according to the present invention.

FIG. 1AT illustrates a preferred embodiment to the present invention.

FIG. 1BT illustrates a preferred embodiment to the present invention.

FIG. 2T illustrates a preferred embodiment to the present invention.

FIG. 3T illustrates a flow diagram for use with the present invention.

FIG. 1M illustrates a general mechanical input system receiving current sensor input, temperature sensor input, or mechanical (compressor electrical contacts) to operate upon a ECM voltage regulator that controls speed of the ECM.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

Current Sensing:

In the following description of the invention, reference is made to the accompanying drawings, which form a part thereof, and in which are shown, by way of illustration, exemplary embodiments illustrating the principles of the present invention and how it may be practiced. It is to be understood that other embodiments may be utilized to practice the present invention, and structural and functional changes may be made thereto without departing from the scope of the present invention.

A unique system, apparatus, and accompanying methods are used to regulate fan speeds used in refrigeration systems. A fan control system, generally referred to by reference numeral 100, includes a voltage control 101, a current sensing relay 102 in communication with voltage controller 101, at least one current sensor 103 in communication with current sensing relay 102, and one or more evaporator fan motor(s) 110. Current sensor 103 is located remotely from the refrigerated chamber in the facility circuit breaker panel. The current sensor senses the presence or absence of electrical current flowing through sensed wire 106. Sensed wire 106 could be any wire in the refrigeration system that carries power, including the compressor power wire or the control system power wire.

It must be pointed out here that the present invention does not necessarily require the use of a solenoid for any portion of the operation. The present invention may be used with a standard thermostat but does not require one. These factors are advantages of the present control system and represent significant improvements over the prior art. In addition, although the present invention is specifically adapted for use with medium temperature systems, the present invention may be used in conjunction with other high and low-temperature-adapted refrigeration systems.

Most of the components used in the control system of the present invention are readily available and understandable to one skilled in the art. Voltage controller 101 is well known in the art and it is of no consequence which type of voltage controller is used in the control system of the present invention. Voltage controller 101 is used inasmuch as it is adaptable with the rest of the components of the present invention.

The type of evaporator fan motor 110 is also well known in the art and the type is not specifically required as long as it is a shaded pole of PSC (permission split capacitor) type motor. The present invention is not limited in applicability to refrigerated chambers, the refrigeration systems of which comprise evaporator fan motors of a particular type, such as series wound motors. The motor is generally recognized within the refrigeration industry and it is typically a shaded pole or PSC type motor. The only requirement is that the evaporator fan motor 110 which is used in the system is readily adaptable for use with the rest of the components in the system of the present invention. The present invention is also not limited in application to refrigerated chambers, the refrigeration systems of which employ two-speed motors as evaporator fan motors.

The system according to the present invention is not dependent upon which kind of metering device is used to modulate refrigerants into the evaporator. Current sensors 103 are also well known in the art and are readily available to one skilled in the art. It is of no consequence which current sensor 103 is used, inasmuch as it works properly with the rest of the components of the present invention. The current sensing relay 102 is also well known in the art and is readily understood by one skilled in the art. It is of no consequence which temperature-sensing relay 102 is actually used in the present invention inasmuch as it works properly with the rest of the components of the present invention.

Voltage controller 101 may embody many different types such s the triac, the quadric, or other similar devices. It is not specifically required in the present invention that any particular device be used. There abound several types of voltage controllers which are well known in the art and which may prove to be equally useful in the present invention. The mentioning of the triac or the quadric is for exemplary or illustrative purposes only. The triac is well known in the art and readily available to one skilled in the art. The particular triac that is used with the control system according to the present invention is of no consequence inasmuch ass it works properly with the other components of the present invention. In the art there are two well known triacs: one is 230 volt and the other is 120 Volt triac. Either is suitable for use with the control system according to the present invention. In addition, some triacs are made with different amperages. Inasmuch as triacs and other similar voltage controllers vary widely with respect to amperages and voltages, the specific type used in the system according to the present invention is of no consequence in so far as it is compatible with the rest of the components of the present invention.

Also known in the art there are quadrics. Quadracs may be used in place of the triac as voltage controller. Both the quadric and the triacs are interchangeable for the purposes and objectives of the present invention or any component of like description.

Voltage controller 101 is in communication with other components of the system in accordance with the present invention through wires, as will be described below. Two wires 111 and 102 are used for the current sensor 103. Reference characters should not be construed to be limiting the scope of the present invention. Wires 111 and 120 are preferably low-voltage wires.

Wire 112 is a common power wire. Contact 113 is a normally closed contact, which transfers power to the voltage controller or directly to the fan motor(s). Wire 114 is a normally open wire, which closes when electric current flow is detected in the wires going through the current sensor. Wire 114 bypasses the voltage controller 101 and wire 115 connects the voltage controller 101 with current sensing relay 102. Wire 116 connects voltage controller 101 with the fan 110 on low-speed operation when there is no current flow detected at the current sensor, sending power through wire 114 and directly to the fan 110. The current sensing relay 102 detects electric current flow and switches the contacts in the relay from normally closed contact low speed, to normally open contact high speed sending power wire 114, which is high speed normal operation.

FIG. 2 illustrates a flow diagram of a preferred method of the present invention. First, in step one 201, current sensor 103 detects whether there is an in electrical flow in sensed wire 106 (on/off). Sensed wire 106 may be the wire carrying power to the compressor or the wire carrying control power. It could also be any other wire carrying power in the refrigeration system.

If there is a current flow in sensed wire 106 detected by the current sensor 103, this is an indication that the system compressor is running. In this case, the fan control system 100 in step two 202 will maintain high speed of the evaporator fan motor 110. However, if there is no electrical current flow detected in sensed wire 106, which indicates that the compressor is not running, in step three 203, evaporator fan motor 110 is set to a lower speed. By setting the evaporator fan motor to a lower speed, two important objectives are achieved. First, lower fan speeds will save upwards of 85% of energy use of the fans along with substantial amounts of financial savings, not to mention the fact that there is less heat generated by the fans at lower speeds. Secondly, a lower fan speed will ensure that there will not be a stratification of the air temperature in the refrigerated chamber. As long as there is air circulation, the refrigerated chamber will be at a constant temperature. Thirdly, by having a lower fan speed, the life of the equipment is thereby extended, due to lower running times. A further advantage provided by the present invention is lowered dehydration in the products, such as flowers or produce in the refrigerated chamber, when the fan is running at lower speed.

Temperature Sensing:

A unique system, apparatus, and accompanying methods are used to regulate fan speeds with freezers and other refrigeration systems. The present invention is described in enabling detail below.

FIGS. 1a and 1b illustrate one preferred embodiment of the present invention. Arrows indicate entering air stream and a discharged air stream in FIGS. 1a and 1b. Fan control system 100 comprises a voltage controller 101, a temperature sensing realy 102, remote air sensor(s) 103, and an evaporator fan motor(s) 110. Remote air sensor(s) 103 are placed in the entering air stream of the evaporator coil 104 and at the point where the discharged air comes off the evaporator coil 104. R1 111 will hereafter denote remote air sensor 1 and R2 120 will hereafter denote remote air sensor 2.

It must be pointed out here that the present invention does not necessarily require the use of a solenoid for any portion of the operation. The present invention may be used with a standard thermostat but does not require one. This is an advantage and a significant improvement over the prior art. In addition, although the present invention is specifically adapted for use with freezers, the present invention may be suitable for other medium and high-temperature adapted refrigeration systems.

Most of the components used in the present invention are readily available and understandable to one skilled in the art. Voltage controller 101 is well known in the art and it is of no consequence which type of voltage controller 101 is used inasmuch as it be adaptable with the rest of the components of the present invention.

The type of evaporator fan motor 110 is well known in the art and the type is not specifically required as long as it is a shaded pole or PSC (permanent split capacitor) type motor. The present invention is not limited in applicability to refrigerated chambers, the refrigeration systems of which comprise evaporator fan motors of a particular type, such as series wound motors. The motor is generally recognized within the refrigerated industry and it is typically a shaded pole or PSC type motor. The only requirement is that the evaporator fan motor 110 which is used is readily adaptable for use with the rest of the components in the present invention. The present invention is also not limited in application to refrigerated chambers the refrigeration systems of which employ two-speed motors as evaporator fan motors.

The present invention is not dependent upon which kind of metering device is used to modulate refrigerants into the evaporator. Remote air sensor(s) 103 is also well known in the art and is readily available to one skilled in the art. It is of no consequence which remote air sensor 103 is used inasmuch as it works properly with the rest of the components of the present invention. The temperature sensing relay 102 is also well known in the art and is readily understood by one skilled in the art. It is of no consequence which temperature sensing relay 102 is actually used in the present invention inasmuch as it works properly with the rest of the components of the present invention.

The voltage controller 101 may embody many different types such as the triac, the quadric, or other similar devices. It is not specifically required in the present invention that any particular device be used. It is not specifically required in the present invention that any particular device be used. There abound several types of voltage controllers which are well known in the art which may prove to be equally useful in the present invention. The mentioning of the triac or the quadric is for exemplary or illustrative purposes only. The triac is well known in the art and readily available to one skilled in the art. The particular triac which is used is of no consequence inasmuch as it works properly with the other components of the present invention. In the art there are two well known triacs: a 230 volt and a 120 volt. It is of no consequence which triac is used between these two, or any other triac-type device. In addition, some triacs are made with different amperages. Inasmuch as triacs and other similar voltage controllers vary idely with respect to amperages and voltages, the specific type used is of no consequence insofar as it is compatible with the rest of the components of the present invention.

Moreover in the art there are quadracs. Quadracs may be used in place of the triac. Both the quadrics and the triacs are interchangeable for the purpose and objectives of the present invention or any component of like-description.

The voltage controller 101 is in communication with other components of the present invention through wires which will be described below. Two wires 112 and 120 are used for the remote air sensor(s) 103 (when there is only one remote air sensor 103, or more than one remote air sensor 102, more or less will be needed and reference characters should not be construed to be limiting the scope of the present invention). Wires 111 and 120 are usually low voltage wires.

Wire 112 is a common power wire. Contact 113 is a normally closed contact which transfers power to the voltage controller or directly to fan motor(s). Wire 114 is a normally open wire which closes when a temperature differential is detected across the coil. Wire 114 bypasses the voltage controller 101. And wire 115 connects the voltage controller 101 with temperature sensing relay 102. Wire 116 connects voltage controller 101 with the fan 110 on low speed operation where there is no temperature differential detected across the evaporator coil sending power through wire 114 and directly to the fan 110. Temperature sensing relay 102 detects the temperature differential and switches the contacts in the relay from normally closed contact low speed to normally open contact high speed sending power through wire 114 which is high speed normal operation.

FIG. 3, illustrates a preferred method of the present invention. First, in step one 201, remote air sensors 103 detect whether there is a differential in temperatures between them. If there is a temperature differential detected by the remote air sensor(s) 203 which indicates the compressor is running—then fan control system 100 in Step two 202, will maintain high speed of the evaporator fan motor 110. However, if there is no temperature differential which indicates that the compressor is not running, in step three 203, then evaporator fan motor 102 is set to a lower speed. By setting the evaporator fan motor 110 to a lower speed two important objectives are achieved. First, lower fan speed will save upwards to 85% of energy of the fans along with a substantial amount of financial savings not to mention the fact that there is less heat generated by the fans at lower speeds. And second, a lower fan speed will ensure that there will not be a stratification of the air temperature. As long as there is air circulation, the box will be at a constant temperature. And third, by having a lower fan speed, the life of the equipment is thereby extended due to lower running times.

Mechanical/Electrical Contact Closing Sensing:

Referring now to FIG. 1M, a mechanical sensing circuit is disclosed wherein the aforementioned current sensing and temperature sensing systems as well as a mechanical sensor, i.e. “compressor electrical contacts” input 302 is applied to a switching relay circuit 304 coupled to a low voltage input circuit 306 which in turn provides a high or low voltage to Electronically Commutated Motor 308 to drive a fan 310 high speed or low speed depending whether the compressor is on or off, respectfully.

It will be apparent to the skilled artisan that there are numerous changes that may be made in embodiments described herein without departing from the spirit and scope of the invention. As such, the invention taught herein by specific examples is limited only by the scope of the claims that follow.

Claims

1. A control system for controlling at least one fan motor in a refrigeration system comprising:

a voltage controller;

a current sensing relay in communication with the voltage controller; and

at least one current sensor in communication with the current sensing relay, whereby the speed of the at least one fan motor is controlled by at least one current sensor.

2. The system according to claim 1, wherein the at least one current sensor is located remotely from the refrigeration system.

3. The system according to claim 1, wherein the voltage controller is a triac.

4. The system according to claim 3, wherein the triac is integrated with the current sensing relay.

5. The system according to claim 1, wherein the voltage controller is a quadric.

6. The system according to claim 5, wherein the quadric is integrated with the current sensing relay.

7. The system according to claim 1, wherein the at least one current sensor is placed in the electrical wiring of the refrigeration system.

8. The system according to claim 1, wherein the at least one current sensor senses the current in the compressor power wiring.

9. The system according to claim 1, wherein the at least one current sensor senses the current in the control power wiring.

10. The system according to claim 7, wherein when the at least one current sensor senses that current is flowing in the wiring, the evaporator fan motor will be set to rotate at high speed.

11. The system according to claim 7, wherein the at least one current sensor senses that no current is flowing in the wiring, the evaporator fan motor will be set to rotate at low speed.

12. A method for controlling a refrigeration evaporator fan motor in a refrigeration system comprising the steps of:

providing a control system having at least one remote current sensor for sensing current flow in the refrigeration system electrical wiring; and

setting the speed of the evaporator fan motor in accordance with the presence or absence of current flow as sensed by the current sensor.

13. A method for controlling a refrigeration evaporator fan motor in a refrigeration system, comprising the steps of:

providing a control system having at least one remote, external temperature sensor, sensing a change a change in temperature entering and exiting the evaporator coil.

setting the speed of the evaporator fan motor in accordance with the presence or absence of said change in temperature.

14. A method for controlling a refrigeration evaporator fan motor in a refrigeration system, comprising the steps of:

providing a control system having at least one remote compressor, electrical contact sensor for sensing when the compressor is turned on;

setting the speed of the evaporator fan motor in accordance with the presence or absence electrical contact continuity.

15. The method according to claims 12, 13, and 14, further comprising the steps of:

setting the speed of the evaporator fan motor to high speed when there is current flow, a temperature differential, and electrical contact sensed by said sensors; and

setting the speed of the evaporator fan motor to low speed when there is no current flow, no temperature differential, and no electrical contact of the compressor sensed by said sensors.