INTERNAL CONTROL SYSTEMS OF EVAPORATOR AND CONDENSER FAN MOTOR ASSEMBLIES OF A REFRIGERATION SYSTEM IN A REFRIGERATOR UNIT

Abstract

A refrigeration system for use in a refrigerator unit, the refrigeration system including a compressor having an ON state and an OFF state, a condenser, a temperature sensor, an evaporator, and an evaporator fan motor assembly. The evaporator fan motor assembly has an evaporator fan motor, a fan blade, and an internal control system. The internal control system of the evaporator fan motor assembly is adapted to sense the compressor state and is further adapted to operate the evaporator fan motor in response to the sensed compressor state. The refrigeration system may further include a condenser fan motor assembly. The condenser fan motor assembly has a condenser fan motor, a fan blade, and an internal control system. The internal control system of the condenser fan motor is adapted to sense the compressor state and is further adapted to operate the condenser fan motor in response to the sensed compressor state.

Description

RELATED APPLICATION

This application claims priority to U.S. Provisional Patent App. No. 61/952,294, filed on Mar. 13, 2014, the contents of which are incorporated herein by reference in their entirety.

FIELD OF THE INVENTION

This invention relates generally to refrigerator units and, more particularly, to refrigerator units that comprise a refrigeration system with an evaporator fan motor assembly having an internal control system and/or a condenser fan motor assembly having an internal control system wherein the evaporator fan motor and/or the condenser fan motor can be operated intermittently for assisting in reducing energy consumption.

BACKGROUND

The principal components of a typical refrigerator unit, such as those used in residential, commercial and industrial applications, include a storage compartment which is refrigerated by a refrigeration system and is used to store and/or display various food products at low temperatures. The refrigeration systems of typical refrigerator units include a refrigerant flowing serially through a compressor, a condenser, a thermal expansion valve or capillary tube, and an evaporator. Additionally a condenser fan motor assembly is used to blow air across the coils of the condenser. An evaporator (cold air) fan motor assembly is used to blow air across the evaporator. In these typical refrigerator units the condenser fan motor runs while the compressor operates (i.e., the compressor ON state). The compressor typically cycles on and off about three times an hour. Additionally, the evaporator fan motor runs both during the compressor ON state and during the compressor OFF state.

The constant running of the evaporator fan motor assists in providing uniform product temperature throughout the interior volume of the storage compartment regardless of the relationship of the ON-OFF state of the compressor ((whether the compressor cycles from the ON state to the OFF state frequently (e.g., more than 6 cycles per hour) or infrequently (e.g., once or twice an hour)). Under some circumstances, the evaporator fan motor can be powered off when the compressor is powered off. This is typically done for energy saving reasons. If the actual compressor run time (i.e., the ratio of on time to real time) is very low because of low ambient temperature or general sizing of the refrigeration system to the volume of the storage compartment, this can lead to instability of the product temperature inside the storage compartment. The product temperature may begin to swing up and down with the compressor cycles, thereby adversely affecting the integrity of the food products stored within the storage compartment. Accordingly, turning off the evaporator fan motor during the compressor OFF state can save energy, but can have a negative effect on the food product.

In prior art refrigerator units, the condenser fan motor runs while the compressor operates (i.e., the compressor ON state) and the evaporator fan motor runs both during the compressor ON state and during the compressor OFF state. The constant running of the evaporator fan motor assists in providing uniform product temperature throughout the interior volume of the storage compartment, however the constant running of the evaporator fan motor also increases the energy consumption of the refrigerator unit. In certain other prior art refrigerator units, an external control system may be employed which may be adapted to control the compressor, condenser fan and/or evaporator fan motor. The control system may be connected to an electronic thermostat and can control each of the refrigeration components based on the temperature sensed by the electronic thermostat. This external control system may be disposed on or in the refrigerator unit. Such an external control system, including the electronic thermostat, may be expensive to design and implement. Additionally, the external control system may need to be tailored to various types and/or sizes of refrigerator units.

SUMMARY OF THE INVENTION

Briefly, therefore, one embodiment of the invention is directed to a refrigeration system in which the condenser fan motor and/or the evaporator fan motor may be operated by control systems internal to each of the condenser fan motor assembly and/or the evaporator fan motor assembly for reduced energy consumption while maintaining uniform product temperature in the storage compartment.

Another embodiment of the invention is directed to a refrigeration system for use in a refrigerator unit, the refrigeration system comprising a compressor having an ON state and an OFF state, a condenser, a thermostat, an evaporator, and an evaporator fan motor assembly comprising an evaporator fan motor, a fan blade, and an internal control system, wherein the internal control system is adapted to sense the compressor state and is further adapted to operate the evaporator fan motor in response to the sensed compressor state.

Another embodiment of the invention is directed to a method of operating a refrigeration system for use in a refrigerator unit, wherein the refrigeration system comprises a compressor having an ON state and an OFF state, a condenser, a thermostat, an evaporator, and an evaporator fan motor assembly comprising an evaporator fan motor, a fan blade, and an internal control system, wherein the internal control system is adapted to repeatedly cycle the evaporator fan motor between an ON state and an OFF state when the compressor is in the OFF state. The method comprises the steps of: turning the compressor to the ON state; sensing by the internal control system of the evaporator fan motor assembly that the compressor is in the ON state and turning the evaporator fan motor to the ON state; turning the compressor to the OFF state; sensing by the internal control system of the evaporator fan motor assembly that the compressor is in the OFF state and repeatedly cycling the evaporator fan motor between the ON state and the OFF state.

BRIEF DESCRIPTION OF THE FIGURES

These and other features, aspects and advantages of the invention will become more fully apparent from the following detailed description, appended claims, and accompanying drawings, wherein the drawings illustrate features in accordance with exemplary embodiments of the invention, and wherein:

FIG. 1 is a right perspective view of a refrigerator unit according to an embodiment of the invention;

FIG. 2 is a schematic drawing of a refrigeration system of a refrigerator unit according to an embodiment of the invention;

FIG. 3 is a wiring diagram of components of a refrigeration system of a refrigerator unit according to an embodiment of the invention;

FIG. 4 is a flowchart of a method of operation of a refrigeration system of refrigerator unit having an evaporator fan motor assembly with an internal control system according to an embodiment of the invention;

FIG. 5 is a flowchart of a method of operation of a refrigeration system of a refrigerator unit having a condenser fan motor assembly with an internal control system according to an embodiment of the invention;

FIG. 6 is a flowchart of a method of operation of a refrigeration system of a refrigerator unit having an evaporator fan motor assembly with an internal control system and a condenser fan motor assembly with an internal control system according to an embodiment of the invention;

FIG. 7 is a time plot of a method of operation of a refrigeration system of a refrigerator unit having an evaporator fan motor assembly with an internal control system and a condenser fan motor assembly with an internal control system according to an embodiment of the invention; and

FIG. 7A is a time plot of a method of operation of a refrigeration system of a refrigerator unit having an evaporator fan motor assembly with an internal control system and a condenser fan motor assembly with an internal control system according to an embodiment of the invention.

DETAILED DESCRIPTION

Before any embodiments of the invention are explained in detail, it will be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it will be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. All numbers expressing measurements and so forth used in the specification and claims are to be understood as being modified in all instances by the term “about.” It should also be noted that any references herein to front and back, right and left, top and bottom and upper and lower are intended for convenience of description, not to limit an invention disclosed herein or its components to any one positional or spatial orientation.

As illustrated in FIG. 1, one embodiment of the invention is a refrigerator unit 10 having a refrigeration system disposed within refrigerator unit 10. In certain embodiments, for example, refrigerator unit 10 may be a glass door merchandiser which may be used to store and display products such as food and/or drinks for sale. However, it will be understood that refrigerator unit 10 may be any type of refrigeration unit, including, but not limited to, residential, commercial and/or industrial refrigerators, vending machines, and freezers. Refrigerator unit 10 may include a lower portion providing a refrigeration system housing 12 and an upper portion providing a cabinet 14. Some or all of components of refrigeration system 110 (see FIG. 2) may be disposed within refrigeration system housing 12. As shown, cabinet 14 includes a top 16, a bottom 18, opposed sides 20 and a back 22 defining a storage compartment 24 having an opening 26. Opening 26, in the embodiment shown, may be closed by a pair of doors 28 which may be substantially identical, each door 28 being attached to one of said cabinet sides 20 in swinging relation to said opening 26. While certain embodiments include a pair of doors 28, it will be understood by one of ordinary skill in the art that any number of doors may be used without departing from the scope of the invention.

FIG. 2 illustrates certain principal components of one embodiment of a refrigeration system 110 for use in a refrigerator unit 10. Refrigeration system 110 may include a compressor 112, a condenser 114 for condensing compressed refrigerant vapor discharged from the compressor 112, a thermal expansion device 118 for lowering the temperature and pressure of the refrigerant, an evaporator 120, and a thermostat or temperature control 130. Thermostat 130 may be adapted to control the operation of refrigeration system 110 in response to the temperatures measured within storage compartment 24. Accordingly, compressor 112 may have an ON state (“ON”) and an OFF state (“OFF”) wherein thermostat 130 causes compressor 112 to turn ON or OFF based on the temperature within storage compartment 24. Thermostat 130 may be a mechanical or electrical thermostat or temperature control. In various embodiments, thermostat 130 may include a relay and capillary tube for measuring the temperature within storage compartment 24 and for controlling compressor 112. The thermal expansion device 118 may include, but is not limited to, a capillary tube, a thermostatic expansion valve or an electronic expansion valve. In certain embodiments, where thermal expansion device 118 is a thermostatic expansion valve or an electronic expansion valve, refrigeration system 110 may also include a temperature sensing bulb (not shown) placed at the outlet of the evaporator 120 to control thermal expansion device 118. As described more fully elsewhere herein, a form of refrigerant cycles through these components via a lines 128a, 128b, 128c.

Refrigeration system 110 may further include a condenser fan motor assembly 115 which may be positioned to blow a gaseous cooling medium (e.g., air) across condenser 114. Condenser fan motor assembly 115 may include a fan motor 115a, fan blade(s) 115b and an internal control system (not shown) adapted to control the operation of condenser fan motor 115a. Condenser fan motor 115a may be connected to fan blade(s) 115b in any manner known in the art to cause fan blade(s) 115b to rotate and thus move air. The internal control system of condenser fan motor assembly 115 may be adapted to sense the ON or OFF state of compressor 112 and may be further adapted to operate condenser fan motor 115a in response to the sensed compressor 112 state (e.g., the ON state or the OFF state).

Additionally, refrigeration system 110 may further include an evaporator fan motor assembly 127 which may be positioned to blow air across evaporator 120 in order to circulate cooled air within refrigerator unit 10. Evaporator fan motor assembly 127 may include a fan motor 127a, fan blade(s) 127b and an internal control system (not shown) adapted to control the operation of evaporator fan motor 127a. Evaporator fan motor 127a may be connected to fan blade(s) 127b in any manner known in the art to cause fan blade(s) 127b to rotate and thus move air. The internal control system of evaporator fan motor assembly 127 may be adapted to sense the ON or OFF state of compressor 112 and may be further adapted to operate evaporator fan motor 127a in response to the sensed compressor 112 state (e.g., the ON state or the OFF state).

The internal control systems in each of evaporator fan motor assembly 127 and condenser fan motor assembly 115 may assist in reducing energy consumption while keeping costs low. The internal control systems may operate evaporator fan motor 127a and condenser fan motor 115a without requiring additional, expensive, electronic temperature controls with specific relays for this purpose. Preferably, evaporator fan motor assembly 127 includes an internal control system and condenser fan motor assembly 115 includes an internal control system. The internal control system of evaporator fan motor assembly 127 may be independent of the internal control system of condenser fan motor assembly 115. Accordingly, the internal control systems of evaporator fan motor assembly 127 and/or condenser fan motor assembly 115 do not need to communicate with one another and/or do not need to rely on one another in order to control evaporator fan motor 127a and/or condenser fan motor 115b.

In various embodiments, fan motors 127a, 115a of evaporator fan motor assembly 127 and condenser fan motor assembly 115, respectively, may be electronically commutated motor(s) (ECMs) that have an internal circuit board modified for the purpose of sensing the compressor line voltage, an in-line circuit, and/or other electric or electronic components (i.e., integrated circuits, microprocessors, memory, etc.) designed for cycling evaporator fan motor 127a and/or condenser fan motor 115a between an OFF state (“OFF”) and an ON state (“ON”) until compressor 112 is turned ON again by thermostat 130. For example, in certain embodiments, evaporator fan motor 127a and/or condenser fan motor 115a can be repeatedly cycled OFF for 5 minutes and then ON for 1 minute. Typical internal ECM motor electronics do not have enough internal board level isolation to properly sense the compressor line voltage, thus condenser fan motor assembly 115 and evaporator fan motor assembly 127 may each incorporate circuit board design and components not found in typical condenser and evaporator fan motor assemblies in order to achieve the board level isolation required for correctly operating condenser fan motor 115a and evaporator fan motor 127a.

Referring now to FIG. 3 a wiring diagram of an embodiment of refrigeration system 110 is illustrated. Evaporator fan motor assembly 127 may be electrically connected to line 134 and neutral wire 136 via power supply wire 137 and neutral wire 138, respectively. Additionally, thermostat 130 may be electrically connected to line 134. Condenser fan motor assembly 115 and compressor 112 may be wired in parallel between thermostat 130 and neutral wire 136. As stated above, in various embodiments, thermostat 130 may include a relay and capillary tube for measuring the temperature within storage compartment 24. When the temperature within storage compartment 24 rises above the desired set temperature, the relay of thermostat 130 closes thereby completing the circuit and tuning ON compressor 112. A digital control input wire 132 may be connected to the live output side of thermostat 130 and may permit internal control system of evaporator fan motor assembly 115 to sense a line voltage in the circuit when the relay of thermostat 130 closes.

The internal control system of condenser fan motor assembly 115 may not require a separate digital control input wire to determine line voltage because the internal control system can sense the line voltage in condenser power line 140 when the relay of thermostat 130 closes. The internal control systems of each of condenser fan motor assembly 115 and evaporator fan motor assembly 127 permit the use of a simple, cheap and reliable mechanical thermostat 130. Accordingly, condenser fan motor assemblies 115 and/or evaporator fan motor assemblies 127 with internal control systems may be placed into existing refrigerator units without the need for costly external control systems. Thus, existing refrigerator units can be retrofitted with condenser fan motor assemblies 115 and/or evaporator fan motor assemblies 127 having internal control systems and energy efficiency gains may be realized with a low cost.

Preliminary testing to date has indicated an estimated energy savings on a typical 115 volt model (two solid door upright refrigerator) of between 15 and 25 percent over current production construction. These numbers may vary based on the volume of storage compartment 24 and the ratio of the size of refrigeration system 110 to the volume of storage compartment 24. For example, in certain embodiments, larger amounts of energy savings may be realized with refrigeration systems 10 that are more lightly loaded (i.e., where compressor 112 is designed to be OFF for longer periods of time).

Having described each of the individual components of one embodiment of refrigeration system 110, the manner in which the components interact and operate in various embodiments may now be described in reference again to FIG. 2. During operation of refrigeration system 110, compressor 112 receives low-pressure, substantially gaseous refrigerant from evaporator 120 through suction line 128c, pressurizes the refrigerant, and discharges high-pressure, substantially gaseous refrigerant through discharge line 128a to condenser 114. In condenser 114, heat is removed from the refrigerant, causing the substantially gaseous refrigerant to condense into a substantially liquid refrigerant.

After exiting condenser 114, the high-pressure, substantially liquid refrigerant is routed through liquid line 128b to thermal expansion device 118 (e.g., a capillary tube, a thermostatic expansion valve, an electronic expansion valve, etc.), which reduces the pressure of the substantially liquid refrigerant for introduction into evaporator 120. As the low-pressure expanded refrigerant is passed through tubing of evaporator 120, the refrigerant absorbs heat from the tubes contained within evaporator 120 and vaporizes as the refrigerant passes through the tubes. This cools evaporator 120 and evaporator fan motor assembly 127 blows air over or through the coils (not shown) of evaporator 120 in order to circulate cooled air within refrigerator unit 10. Low-pressure, substantially gaseous refrigerant is discharged from the outlet of evaporator 120 through suction line 128c, and is reintroduced into the inlet of compressor 112.

Operation of Evaporator Fan Motor Assembly

In certain embodiments, refrigeration system 110 of refrigerator unit 10 may include an evaporator fan motor assembly 127 having an internal control system for repeatedly cycling evaporator fan motor 127a between an ON state (“ON”) and an OFF state (“OFF”). This cycling can be intermittent (i.e., the OFF time and the ON time do not need to be equal). As stated above, evaporator fan motor assembly 127 may include a fan motor 127a, fan blade(s) 127b, and an internal control system (not shown) adapted to control the operation of evaporator fan motor 127a. The internal control system of evaporator fan motor assembly 127 may be adapted to sense the compressor line voltage via digital control input wire 132 (see FIG. 3) such that the internal control system may be able to sense when compressor 112 is turned ON or OFF by thermostat 130. Accordingly, the internal control system may control evaporator fan motor 127a without the need for an external and/or additional control system.

Referring now to FIG. 4, one embodiment of internal control of evaporator fan motor assembly 127 is described in detail. At step 300, compressor 112 is turned ON by thermostat 130. At step 302, the internal control system of evaporator fan motor assembly 127 senses that compressor 112 has turned ON and turns ON evaporator fan motor 127a causing fan blade(s) 127b to rotate and blow air across evaporator 120. Accordingly, evaporator fan motor 127a can operate continuously while compressor 112 is ON. At step 304, compressor 112 is turned OFF by thermostat 130. In certain embodiments, during optional steps 306, 308 and 310, while compressor 112 remains OFF and for a second time interval after compressor 112 has turned OFF, evaporator fan motor 127a may remain ON. By continuing to operate evaporator fan motor 127a for a period of time after compressor 112 turns OFF, cooling of storage compartment 24 may continue because residual cool refrigerant remains in evaporator 120 even after compressor 112 stops running.

The internal control system of condenser fan motor assembly 127 may include a timer for measuring elapsed time. The timer may be reset each time compressor 112 turns ON. In certain embodiments, the internal control system of evaporator fan motor assembly 127 may include a processor which may provide a timing function. The timer may be implemented via hardware, software, and/or firmware within the internal control system of evaporator fan motor assembly 127 in any manner known in the art without departing from the scope of the invention. When the second time interval has elapsed, at step 308, the internal control system of evaporator fan motor assembly 127 turns OFF evaporator fan motor 127a at step 312. In certain embodiments where optional steps 306, 308 and 310 are not performed, when compressor 112 is turned OFF at step 304, internal control system of evaporator fan motor assembly 127 turns OFF evaporator fan motor 127a at step 312. Accordingly, in certain embodiments, evaporator fan motor 127a may not continue to remain ON for a second time interval.

Then at step 314, the internal control system of evaporator fan motor assembly 127 monitors whether compressor 112 has turned ON. As long as compressor 112 remains OFF, evaporator fan motor 127a may repeatedly cycle ON and OFF, thereby taking advantage of the energy savings by turning OFF evaporator fan motor 127a for a period of time. However, the temperature in storage compartment 24 may be maintained by turning ON evaporator fan motor 127a for a period of time. Therefore, while compressor 112 is OFF, the internal control system of evaporator fan motor assembly 127 keeps evaporator fan motor 127a OFF during a third time interval at step 316. When the third time interval has elapsed, the internal control system of evaporator fan motor assembly 127 turns ON evaporator fan motor 127a at step 318 causing fan blade(s) 127b to rotate and blow air across evaporator 120. Then at step 320, the internal control system of evaporator fan motor assembly 127 monitors whether compressor 112 has turned ON. As long as compressor 112 remains OFF, the internal control system of evaporator fan motor assembly 127 keeps evaporator fan motor 127a ON during a fourth time interval at step 324.

When the fourth time interval has elapsed, at step 322, the internal control system of evaporator fan motor assembly 127 turns OFF evaporator fan motor 127a and the process returns to step 312. This process may then repeat wherein the internal control system of the evaporator fan motor assembly 127 repeatedly cycles evaporator fan motor 127a ON and OFF while compressor 112 is OFF. By running evaporator fan motor 127a during repeated fourth time intervals, air will still be circulated across evaporator 120 by fan blade(s) 127b to maintain the temperature in storage compartment 24. Additionally, by keeping evaporator fan motor 127a OFF during repeated third time intervals, the heat generated by evaporator fan motor assembly 127 may be reduced, thereby reducing heat transfer from evaporator fan motor assembly 127 into storage compartment 24. In certain embodiments, the amount of air required to maintain a uniform temperature in storage compartment 24 during the compressor 112 OFF state may be reduced by as much as a factor of ten (10) as compared to the compressor 112 ON state.

As shown at steps 306 (optional step), 314, and 320, if compressor 112 turns ON at any point, the cycle will be restarted at step 302 and evaporator fan motor 127a will be turned ON or will remain ON. Accordingly, the compressor 112 ON state may interrupt the intermittent operation of evaporator fan motor assembly 127 at any time.

The second, third and fourth intervals of time as described in connection with steps 308 (optional step), 316, and 322 may be any length of time and may vary according to a variety of design and/or operating parameters including, but not limited to, storage compartment 24 volume, ambient temperatures, storage compartment 24 operating temperature, etc. In certain embodiments, for example, the second interval of time, as described at step 308, may be about zero seconds to about 1 minute (e.g., about zero seconds, about 5 seconds, about 10 seconds, about 15 seconds, about 20 seconds, about 25 seconds, about 30 seconds, about 35 seconds, about 40 seconds, about 45 seconds, about 50 seconds, about 55 seconds, about 60 seconds). In certain embodiments, for example, the third interval of time, as described at step 316, may be about 1 minute to about 7 minutes (e.g., about 1 minute, about 2 minutes, about 3 minutes, about 4 minutes, about 5 minutes, about 6 minutes, about 7 minutes). In certain embodiments, for example, the fourth interval of time, as described at step 322, may be about 15 seconds to about 2 minutes (e.g., about 15 seconds, about 30 seconds, about 45 seconds, about 60 seconds, about 1 minute and 15 seconds, about 1 minute and 30 seconds, about 1 minute and 45 seconds, about 2 minutes).

Operation of Condenser Fan Motor Assembly

In certain embodiments, refrigeration system 110 of refrigerator unit 10 may additionally or alternatively include a condenser fan motor assembly 115 having an internal control system independent from the internal control system of evaporator fan motor assembly 127. As stated above, condenser fan motor assembly 115 may include a fan motor 115a, fan blade(s) 115b, and an internal control system (not shown) adapted to control the operation of condenser fan motor 115a. The internal control system may be adapted to sense the compressor line voltage, such that the internal control system of condenser fan motor assembly 115 may be able to sense when compressor 112 is turned ON or OFF by thermostat 130. Accordingly, the internal control system of condenser fan motor assembly 115 may control condenser fan motor 115a without the need for an external and/or additional control system.

Referring now to FIG. 5, one embodiment of a method of internal control of condenser fan motor assembly 115 is described in detail. At step 400, compressor 112 is turned ON by thermostat 130. At step 402, the internal control system of condenser fan motor assembly 115 senses that compressor 112 has turned ON and turns condenser fan motor 115a ON such that condenser fan motor 115a and fan blade(s) 115b run in a REVERSE DIRECTION. This is known as a Reverse-on-Start (ROS) function. The ROS function of condenser fan motor assembly 115 provides advantages over the prior art in that it may assist in keeping condenser 114 clean by blowing accumulated dirt and debris off of the coil (not shown) of condenser 114 during the first mode of operation. A dirty condenser coil can double the energy consumption of refrigeration system 110 in only a few months. A dirty condenser coil can also cause premature compressor 112 failures due to overheating. The internal control system of condenser fan motor assembly 115 continues to run condenser fan motor 115a and fan blade(s) 115b in the REVERSE DIRECTION until a first time interval has elapsed as indicated at step 404.

Accordingly, the internal control system of condenser fan motor assembly 115 may include a timer for measuring elapsed time. The timer may be reset each time compressor 112 turns ON. In certain embodiments, the internal control system of condenser fan motor assembly 115 may include a processor which may provide a timing function. The timer may be implemented via hardware, software, and/or firmware within the internal control system of condenser fan motor assembly 115 in any manner known in the art without departing from the scope of the invention. In various embodiments, the first time interval can be from about 5 seconds to about 60 seconds (e.g., about 5 seconds, about 10 seconds, about 15 seconds, about 20 seconds, about 25 seconds, about 30 seconds, about 35 seconds, about 40 seconds, about 45 seconds, about 50 seconds, about 55 seconds, about 60 seconds). In certain embodiments, for example, first time interval can be from about 20 seconds to about 35 seconds. In other embodiments, first time interval can be about 30 seconds.

After the first time interval has elapsed, at step 406, the internal control system of condenser fan motor assembly 115 turns condenser fan motor 115a ON such that condenser fan motor 115a and fan blade(s) 115b run in a FORWARD DIRECTION. Accordingly, at this step, condenser fan motor 115a and fan blade(s) 115b turn in the “normal direction” while compressor 112 remains ON. At step 408, compressor 112 is turned OFF by thermostat 130. At step 410, the internal control system of condenser fan motor assembly 115 senses that compressor 112 has turned OFF and turns condenser fan motor 115a OFF. Condenser fan motor 115a then remains OFF until thermostat 130 turns compressor 112 back ON.

In certain embodiments, there may be a pause between condenser fan motor 115a and fan blade(s) 115b running in the REVERSE DIRECTION and condenser fan motor 115a and fan blade(s) 115b running in the FORWARD DIRECTION. This pause may allow condenser fan motor 115a and/or fan blade(s) 115b of condenser fan motor assembly 115 to stop rotating. In some embodiments, for example, the pause may be from about 1 second to about 15 seconds (e.g., about 1 second, about 2 seconds, about 3 seconds, about 5 seconds, about 6 seconds, about 7 seconds, about 8 seconds, about 9 seconds, about 10 seconds, about 11 seconds, about 12 seconds, about 13 seconds, about 14 seconds, about 15 seconds).

Operation of Evaporator Fan and Condenser Fan Motor Assemblies

In certain embodiments, refrigeration system 110 of refrigerator unit 10 may include both an evaporator fan motor assembly 127 and a condenser fan motor assembly 115 wherein each may include a fan motor 127a, 115a, fan blade(s) 127b, 115b and an independent internal control system (not shown) adapted to control the operation of evaporator fan motor 127a and condenser fan motor 115a, respectively. As described above, the internal control systems of each of evaporator fan motor assembly 127 and condenser fan motor assembly 115 may be adapted to sense the compressor line voltage, such that the internal control systems may be able to independently sense the compressor 112 ON or OFF state. Accordingly, the internal control systems of each of evaporator fan motor assembly 127 and condenser fan motor assembly 115 may control evaporator fan motor 127a and condenser fan motor 115a, respectively, without the need for an external and/or additional control system.

Referring now to FIG. 6, one embodiment of a method of internal control of evaporator fan motor assembly 127 and condenser fan motor assembly 115 is described in detail. At step 500, compressor 112 is turned ON by thermostat 130. At step 502, the internal control system of evaporator fan motor assembly 127 senses that compressor 112 has turned ON and turns evaporator fan motor 127a ON causing fan blade(s) 127b to rotate and blow air across evaporator 120. Simultaneously or shortly after step 502, at step 504, the internal control system of condenser fan motor assembly 115 senses that compressor 112 has turned ON and turns condenser fan motor 115a ON such that condenser fan motor 115a and fan blade(s) 115b run in a REVERSE DIRECTION. The internal control system of condenser fan motor assembly 115 continues to run condenser fan motor 115a and fan blade(s) 115b in the REVERSE DIRECTION until a first time interval has elapsed as indicated at step 506. Accordingly, the internal control system of condenser fan motor assembly 115 may include a timer for measuring elapsed time. The timer may be reset each time compressor 112 turns ON. In certain embodiments, the internal control system of condenser fan motor assembly 115 may include a processor which may provide a timing function. The timer may be implemented via hardware, software, and/or firmware within the internal control system of condenser fan motor assembly 115 in any manner known in the art without departing from the scope of the invention.

After the first time interval has elapsed, at step 508, the internal control system of condenser fan motor assembly 115 turns ON condenser fan motor 115a such that condenser fan motor 115a and fan blade(s) 115b run in a FORWARD DIRECTION. Accordingly, at this step, condenser fan motor 115a and fan blade(s) 115b turn in the “normal direction” while compressor 112 remains ON. At step 510, compressor 112 is turned OFF by thermostat 130. At step 512, the internal control system of condenser fan motor assembly 115 senses that compressor 112 has turned OFF and turns OFF condenser fan motor 115a. Condenser fan motor 115a then remains OFF until thermostat 130 turns compressor 112 back ON.

In certain embodiments, there may be a pause between condenser fan motor 115a and fan blade(s) 115b running in the REVERSE DIRECTION and condenser fan motor 115a and fan blade(s) 115b running in the FORWARD DIRECTION. This pause may allow condenser fan motor 115a and/or fan blade(s) 115b of condenser fan motor assembly 115 to stop rotating. In some embodiments, for example, the pause may be from about 1 second to about 15 seconds (e.g., about 1 second, about 2 seconds, about 3 seconds, about 5 seconds, about 6 seconds, about 7 seconds, about 8 seconds, about 9 seconds, about 10 seconds, about 11 seconds, about 12 seconds, about 13 seconds, about 14 seconds, about 15 seconds).

In certain embodiments, during optional steps 514, 516 and 518, while compressor 112 remains OFF and for a second time interval after compressor 112 has turned OFF, evaporator fan motor 127a remains ON. By continuing to operate evaporator fan motor 127a for a period of time after compressor 112 turns OFF, cooling of storage compartment 24 may continue because residual cool refrigerant remains in evaporator 120 even after compressor 112 stops running. Accordingly, the internal control system of condenser fan motor assembly 127 may include a timer for measuring elapsed time. The timer may be reset each time compressor 112 turns ON. In certain embodiments, the internal control system of evaporator fan motor assembly 127 may include a processor which may provide a timing function. The timer may be implemented via hardware, software, and/or firmware within the internal control system of evaporator fan motor assembly 127 in any manner known in the art without departing from the scope of the invention. When the second time interval has elapsed, the internal control system of evaporator fan motor assembly 127 turns OFF evaporator fan motor 127a at step 520. In certain embodiments where optional steps 514, 516 and 518 are not performed, when compressor 112 is turned OFF at step 512, internal control system of evaporator fan motor assembly 127 turns OFF evaporator fan motor 127a at step 520. Accordingly, in certain embodiments, evaporator fan motor 127a may not remain ON for a second time interval.

Then at step 522, the internal control system of evaporator fan motor assembly 127 monitors whether compressor 112 has turned ON. As long as compressor 112 remains OFF, evaporator fan motor 127a may repeatedly cycle ON and OFF thereby taking advantage of the energy savings by turning OFF evaporator fan motor 127a for a period of time. However, the temperature in storage compartment 24 may be maintained by turning evaporator fan motor 127a ON for a period of time. Therefore, while compressor 112 is OFF, the internal control system of evaporator fan motor assembly 127 keeps evaporator fan motor 127a OFF during a third time interval at step 524. When the third time interval has elapsed, the internal control system of evaporator fan motor assembly 127 turns ON evaporator fan motor 127a at step 526 causing fan blade(s) 127b to rotate and blow air across evaporator 120. Then at step 528, the internal control system of evaporator fan motor assembly 127 monitors whether compressor 112 has turned ON. As long as compressor 112 remains OFF, the internal control system of evaporator fan motor assembly 127 keeps evaporator fan motor 127a ON during a fourth time interval at step 532.

When the fourth time interval has elapsed, at step 530, the internal control system of evaporator fan motor assembly 127 turns OFF evaporator fan motor 127a and the process returns to step 520. This process may then repeat wherein the internal control system of the evaporator fan motor assembly 127 intermittently cycles evaporator fan motor 127a ON and OFF while compressor 112 is OFF. By running evaporator fan motor 127a during repeated fourth time intervals, air will still be circulated across evaporator 120 to maintain the temperature in storage compartment 24. Additionally, by keeping evaporator fan motor 127a OFF during repeated third time intervals, the heat generated by evaporator fan motor assembly 127 may be reduced, thereby reducing heat transfer from evaporator fan motor assembly 127 into storage compartment 24. In certain embodiments, the amount of air required to maintain a uniform temperature in storage compartment 24 during the compressor 112 OFF state may be reduced by as much as a factor of 10 as compared to the compressor 112 ON state.

As shown at steps 514 (optional step), 522, and 528, if compressor 112 turns ON at any point, the cycle will be restarted at step 502 and evaporator fan motor 127a will be turned ON or will remain ON. Accordingly, the compressor 112 ON state may interrupt the intermittent operation of evaporator fan motor assembly 127 at any time.

The first, second, third and fourth intervals of time as described in connection with steps 506, 516 (optional step), 524, and 530 may be any length of time and may vary according to a variety of design and/or operating parameters including, but not limited to, storage compartment 24 volume, ambient temperatures, storage compartment 24 operating temperature, etc. In various embodiments, the first time interval, as described at step 506, can be from about 5 seconds to about 60 seconds (e.g., about 5 seconds, about 10 seconds, about 15 seconds, about 20 seconds, about 25 seconds, about 30 seconds, about 35 seconds, about 40 seconds, about 45 seconds, about 50 seconds, about 55 seconds, about 60 seconds). In certain embodiments, for example, first time interval can be from about 20 seconds to about 35 seconds. In other embodiments, first time interval can be about 30 seconds. In certain embodiments, for example, the second interval of time, as described at step 516, may be about zero seconds to about 1 minute (e.g., about zero seconds, about 5 seconds, about 10 seconds, about 15 seconds, about 20 seconds, about 25 seconds, about 30 seconds, about 35 seconds, about 40 seconds, about 45 seconds, about 50 seconds, about 55 seconds, about 60 seconds). In certain embodiments, for example, the third interval of time, as described at step 524, may be about 1 minute to about 7 minutes (e.g., about 1 minute, about 2 minutes, about 3 minutes, about 4 minutes, about 5 minutes, about 6 minutes, about 7 minutes). In certain embodiments, for example, the fourth interval of time, as described at step 530, may be about 15 seconds to about 2 minutes (e.g., about 15 seconds, about 30 seconds, about 45 seconds, about 60 seconds, about 1 minute and 15 seconds, about 1 minute and 30 seconds, about 1 minute and 45 seconds, about 2 minutes).

This process is alternatively described in FIG. 7 which illustrates a time plot of the operating states of compressor 112, condenser fan motor assembly 115 and evaporator fan motor assembly 127. While compressor 112 is OFF, condenser fan motor 115a and evaporator fan motor 127a are OFF. Compressor 112 is then turned ON by thermostat 130 and the timers of the internal control systems of condenser fan motor assembly 115 and evaporator fan motor assembly 127 are reset to an initial time t₀. At time t₀, the internal control system of condenser fan motor assembly 115 turns condenser fan motor 115a ON in a REVERSE DIRECTION and the internal control system of evaporator fan motor assembly 127 turns evaporator fan motor 127a ON. At time t₁, after a first time interval has elapsed (t₀ to t₁), the internal control system of condenser fan motor assembly 115 turns condenser fan motor 115a ON in a FORWARD DIRECTION. Then at time t₂, compressor 112 is turned OFF by thermostat 130 and the internal control system of condenser fan motor assembly 115 senses that compressor 112 has turned OFF and turns condenser fan motor 115a OFF.

Also at time t₂, internal control system of evaporator fan motor assembly 127 senses that compressor 112 has turned OFF and may optionally keep evaporator fan motor 127a running for a second time interval from t₂ to t₃. At time t₃, after the second time interval has elapsed, the internal control system of evaporator fan motor assembly 127 turns evaporator fan motor 127a OFF. In certain embodiments at time t₂, if internal control system of evaporator fan motor assembly 127 senses that compressor 112 has turned OFF the internal control system of evaporator fan motor assembly 127 turns evaporator fan motor 127a OFF at time t₂. Accordingly, in certain embodiments, evaporator fan motor 127a may be OFF from t₂ to t₃ (see FIG. 7A).

Then during a third time interval from t₃ to t₄, evaporator fan motor 127a remains OFF. At time t₄, the internal control system of evaporator fan motor assembly 127 turns evaporator fan motor 127a ON and evaporator fan motor 127a remains ON until a fourth time interval has elapsed (from t₄ to t₅). The internal control system of evaporator fan motor assembly 127 then cycles evaporator fan motor 127a ON and OFF during successive third (from t₅ to t₆) and fourth (from t₆ to t₇) time intervals until compressor 112 turns back ON wherein the process restarts and the time is reset to t₀. Although only two successive third and fourth time intervals are illustrated in FIGS. 7 and 7A, it will be understood by one skilled in the art that any number of third and fourth time intervals may occur where evaporator fan motor assembly intermittently operates between the compressor being ON without departing from the scope of the invention.

While various steps are described herein in one order, it will be understood that other embodiments of the method can be carried out in any order and/or without all of the described steps without departing from the scope of the invention.

Thus, there has been shown and described novel methods and apparatuses of a refrigerator unit that comprises a refrigeration system with an evaporator fan motor assembly having an internal control system and/or a condenser fan motor assembly having an internal control system wherein the evaporator fan motor and/or the condenser fan motor can be operated intermittently, which overcome many of the problems of the prior art set forth above. It will be apparent, however, to those familiar in the art, that many changes, variations, modifications, and other uses and applications for the subject devices and methods are possible. All such changes, variations, modifications, and other uses and applications that do not depart from the spirit and scope of the invention are deemed to be covered by the invention which is limited only by the claims which follow.

Claims

1. A refrigeration system for use in a refrigerator unit, the refrigeration system comprising:

(i) a compressor having an ON state and an OFF state;

(ii) a condenser;

(iii) a thermostat;

(iv) an evaporator; and

(v) an evaporator fan motor assembly comprising an evaporator fan motor, a fan blade, and an internal control system, wherein the internal control system is adapted to sense the compressor state and is further adapted to operate the evaporator fan motor in response to the sensed compressor state.

2. The refrigeration system of claim 1 wherein the refrigerator unit is a merchandiser.

3. The refrigeration system of claim 1 wherein the thermostat comprises a mechanical thermostat.

4. The refrigeration system of claim 3 wherein the mechanical thermostat comprises a capillary tube and a relay.

5. The refrigeration system of claim 1, wherein the internal control system of the evaporator fan motor assembly is adapted to repeatedly cycle the evaporator fan motor between an ON state and an OFF state when the compressor is in the OFF state.

6. The refrigeration system of claim 5, wherein the evaporator fan motor is adapted to be in the OFF state for a third time interval and the evaporator fan motor is adapted to be in the ON state for a fourth time interval.

7. The refrigeration system of claim 1, further comprising a condenser fan motor assembly comprising a condenser fan motor, a fan blade, and an internal control system, wherein the internal control system is adapted to sense the compressor state and is further adapted to operate the condenser fan motor in response to the sensed compressor state.

8. The refrigeration system of claim 7, wherein the internal control system of the condenser fan motor assembly is adapted to operate the condenser fan motor in a reverse direction during a first time interval after the compressor has turned to the ON state, and is adapted to operate the condenser fan motor in a forward direction after the first time interval.

9. A method of operating a refrigeration system for use in a refrigerator unit, wherein the refrigeration system comprises a compressor having an ON state and an OFF state, a condenser, a thermostat, an evaporator, and an evaporator fan motor assembly comprising an evaporator fan motor, a fan blade, and an internal control system, wherein the internal control system is adapted to repeatedly cycle the evaporator fan motor between an ON state and an OFF state when the compressor is in the OFF state, the method comprising the steps of:

turning the compressor to the ON state;

sensing by the internal control system of the evaporator fan motor assembly that the compressor is in the ON state and turning the evaporator fan motor to the ON state;

turning the compressor to the OFF state;

sensing by the internal control system of the evaporator fan motor assembly that the compressor is in the OFF state and repeatedly cycling the evaporator fan motor between the ON state and the OFF state.

10. The method of claim 9 wherein the refrigerator unit is a merchandiser.

11. The method of claim 9 wherein the thermostat comprises a mechanical thermostat.

12. The method of claim 11 wherein the mechanical thermostat comprises a capillary tube and a relay.

13. The method of claim 9, wherein the evaporator fan motor is in the OFF state for a third time interval and the evaporator fan motor is in the ON state for a fourth time interval.

14. The method of claim 9 wherein the refrigeration system further comprises a condenser fan motor assembly comprising a condenser fan motor, a fan blade, and an internal control system, wherein the internal control system is adapted to operate the condenser fan motor in response to the sensed compressor state and the method further comprises the steps of:

sensing by the internal control system of the condenser fan motor assembly that the compressor is in the ON state and during a first time interval after the compressor has turned to the ON state, operating the condenser fan motor in a reverse direction;

after the first time interval and while the compressor is in the ON state, operating the condenser fan motor in a forward direction;

sensing by the internal control system of the condenser fan motor assembly that the compressor is in the OFF state and turning the condenser fan motor to an OFF state.