Patent Publication Number: US-11034514-B2

Title: Actively cooled waste receptacle

Description:
FIELD 
     The specification relates generally to waste storage, and specifically to an actively cooled waste receptacle. 
     BACKGROUND 
     Various facilities, including commercial, industrial, medical, and residential locations, employ provisional waste storage prior to transporting the waste off-site. For example, some municipalities have implemented landfill diversion programs in which residents and businesses separate food and other organic waste from non-organic waste. The resulting collections of organic waste, which are typically stored in bins or bags prior to transportation to municipal composting facilities, can generate foul odors, attract pests, and potentially present a source of disease or infection. 
     Further examples of the collection of organic waste include the provisional storage of soiled diapers before municipal collection, and the provisional storage of various types of medical waste prior to permanent disposal (e.g. via incineration). These collections can lead to offensive odors, and can also present infection risks. 
     The above problems with provisional on-site storage of waste, and particularly organic waste, can lead to reduced compliance with municipal waste programs (e.g. users may simply stop sorting organic refuse), medical facility procedures (e.g. workers may improperly dispose of certain waste, or increase the frequency with which collection receptacles are emptied, raising labour and material costs) and the like. 
     Various attempts have been made to mitigate the above issues using refrigeration. For example, U.S. Pat. No. 3,041,852 describes a waste receptacle whose interior is cooled via refrigeration coils within the receptacle&#39;s walls. The coils, in turn, are cooled by a heat pump that is motivated by an external source such as a household refrigerator. U.S. Pat. No. 3,161,030 also describes a waste receptacle with refrigeration coils contained within the inner walls and cooled by a vapor refrigeration cycle employing a compressor. 
     U.S. Pat. No. 3,650,120 describes a system acting as a hybrid trash compactor and freezer, that generates frozen pucks of refuse by means of wetting, compressing, and freezing (rather than simply cooling). 
     U.S. Pat. No. 5,181,393 describes a waste container that reduces the growth of bacteria by storing organic waste materials such as compost, medical waste, and diapers in a cool, low humidity environment. In this instance a UV light is also incorporated to further reduce bacterial growth. As with the previous examples, the refrigeration coils are contained within the inner walls of the volume. 
     U.S. Pat. No. 5,614,107 describes an industrial method of processing liquid sewage sludge by freezing the sludge in order to draw out the moisture, effectively freeze-drying the sludge to transform the sewage into a powder. U.S. Pat. No. 6,092,382 proposes dehydrating household waste by chilling the waste to temperatures just above freezing and in a separate compartment sharing the same atmosphere, accumulating liquid water on refrigeration coils by condensation and then allowing the condensate to run off to a collector where it is evaporated into the atmosphere of the home. 
     As a further example, German Utility Model No. DE20311066U1 describes a waste receptacle for organic waste or compost, whose interior is cooled by a thermoelectric device employing the Peltier effect. 
     The above-mentioned attempts to handle organic waste while reducing the incidence of odors, pest attraction and the like suffer from various drawbacks. For example, the arrangement of refrigeration coils may complicate the manufacture and maintenance of such devices, as well as reduce the cooling effectiveness of the devices. Some of the above-mentioned devices may also be difficult for users to load and unload. 
     SUMMARY 
     According to an aspect of the specification, an actively cooled waste receptacle is provided, comprising: an insulated container including (i) an inner wall defining a chamber having an opening for receiving the waste, and (ii) an outer wall surrounding the inner wall and joined to the inner wall at the opening; a cover configured to prevent access to the chamber via the opening in a closed position, and to allow access to the chamber via the opening in an open position; and a heat pump including an interior heat exchanger exposed to the chamber, the heat pump configured to cool the chamber by absorbing heat from air within the chamber via the interior heat exchanger, and transferring the heat outside the insulated container. 
    
    
     
       BRIEF DESCRIPTIONS OF THE DRAWINGS 
       Embodiments are described with reference to the following figures, in which: 
         FIG. 1  depicts a front orthographic cutaway view of an actively cooled waste receptacle with a removable bin omitted, according to a non-limiting embodiment; 
         FIG. 2  depicts a side section view of the receptacle of  FIG. 1 , according to a non-limiting embodiment; 
         FIG. 3  depicts the removable bin of the receptacle of  FIG. 1 , according to a non-limiting embodiment; 
         FIG. 4  depicts a rear orthographic view of an actively cooled waste receptacle in an open position, according to another non-limiting embodiment; 
         FIG. 5  depicts a side partial section view of the receptacle of  FIG. 4  in a closed position, according to another non-limiting embodiment; 
         FIG. 6  depicts a front orthographic view of the receptacle of  FIG. 4  in the closed position, according to another non-limiting embodiment; 
         FIG. 7  depicts a front orthographic cutaway view of an actively cooled waste receptacle, according to a further non-limiting embodiment; 
         FIG. 8  depicts a rear orthographic view of the receptacle of  FIG. 7 , according to a further non-limiting embodiment; 
         FIG. 9  depicts an exploded view of the receptacle of  FIG. 7 , according to a further non-limiting embodiment; 
         FIG. 10  depicts a front orthographic cutaway view of an actively cooled waste receptacle with a removable cart in an unloaded position, according to a still further non-limiting embodiment; 
         FIG. 11A  depicts a rear view of the receptacle of  FIG. 10 , according to a still further non-limiting embodiment; 
         FIG. 11B  depicts a detailed view of certain components of the receptacle as shown in  FIG. 11A , according to a still further non-limiting embodiment; and 
         FIG. 12  depicts a front orthographic view of the receptacle of  FIG. 10  with the removable cart in a loaded position, according to a still further non-limiting embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       FIGS. 1-3  depict an actively cooled waste receptacle  100  (also referred to simply as receptacle  100 ) according to a first embodiment. In the present embodiment, the receptacle  100  is a standalone freezer appliance comprising a heat pump (e.g. a vapor compression heat pump, thermoelectric heat pump, absorption heat pump or the like) and an insulated container  101 . The insulated container  101  includes an inner wall  101 - 1  defining a chamber  101 - 2  having an opening  101 - 3  for receiving any of a variety of waste (e.g. organic waste). The insulated container  101  also includes an outer wall  101 - 4  surrounding the inner wall  101 - 1  and joined to the inner wall  101 - 1  at the opening  101 - 3 . The nature of the inner and outer walls  101 - 1  and  101 - 4  is not particularly limited: the walls can be made of any suitable material, and can define a cavity therebetween containing insulating material. In other embodiments, the walls and the insulating material can be an integral component fabricated from a single material, and the walls  101 - 1  and  101 - 4  can simply be the inner and outer surfaces of that component. 
     The receptacle  100  also includes a cover, which in the present embodiment is an insulated lid  102 , for sealing and enclosing the container  101  from the top (though as will be seen below, other orientations are also contemplated for the cover). The lid  102  is configured to prevent access to the chamber  101 - 2  via the opening  101 - 3  in a closed position, and to allow access to the chamber  101 - 2  via the opening  101 - 3  in an open position (shown in  FIG. 1 ). In the present example, the lid  102  is movably coupled to the container  101 , for example via a hinge. In other embodiments, the lid  102  can be detachable from the container  101  rather than being movable coupled to the container  101 . The lid  102  has a gasket  103  to form a substantially airtight seal with an intermediate lip  104  formed by the inner wall  101 - 1  of the container  101 . 
     The above-mentioned heat pump includes an interior heat exchanger, which in the present embodiment is an evaporator  105  (specifically, a roll-bond type evaporator, although other types of evaporators may also be employed) contained within the container  101  and exposed to the chamber  101 - 2  (that is, exposed directly to the air within the chamber  101 - 2  rather than being embedded between the inner and outer walls  101 - 1  and  101 - 4 ). Further, in the present embodiment, the evaporator  105  is supported by a mounting member (which may, for example, be a portion of the evaporator itself) within the chamber  101 - 2  spaced apart from the inner wall  101 - 1  (i.e. stood off from the rear wall of the container  101  as seen in  FIG. 1 ). Thus, air within the chamber  101 - 2  can travel not only along the inner side of the evaporator  105  (that is, the side closest to the center of chamber  101 - 2 ), but also between the evaporator  105  and the nearest inner wall  101 - 1 ). 
     The interior heat exchanger (i.e. the evaporator  105 , in the present embodiment) has a substantially planar configuration and is mounted substantially parallel to a surface of the inner wall  101 - 1 . In particular, in the embodiment shown in  FIG. 1 , the evaporator is positioned substantially vertically (as seen when the receptacle  100  is in use). 
     The heat pump can have a variety of configurations. As noted above, in the present example, the heat pump is a vapor compression heat pump, and thus the evaporator  105  is connected to a compressor  106  and an exterior heat exchanger in the form of a condenser  107  via connecting refrigeration tubing  108  (completing the heat pump circuit) through the walls of the container  101 . The exterior heat exchanger exhausts heat absorbed by the interior heat exchanger from the chamber  101 - 2 . More specifically, in the present embodiment a refrigerant fluid is metered by an expansion valve or capillary (not shown) into the evaporator  105 , such that the fluid expands into a gas in the evaporator  105  and absorbs heat from the chamber  101 - 2 . The fluid then travels to the compressor  106  and is compressed before travelling through the condenser  107 , which removes heat from the fluid before the fluid returns to the evaporator  105  via the expansion valve or capillary. 
     The embodiment shown in  FIG. 1  is integrated vertically. In other words, the compressor  106 , the condenser  107 , and a condenser fan  109  are contained below the container  101 , within a base  110  that forms the bottom of the receptacle  100  when in use. A plurality of pylons  111  connect the base  110  to the container  101 . The lid  102  rests on top of the container  101 . A shell  112  can be provided that fits over the base  110  and the container  101  to form the exterior of the receptacle  100 , providing protection to the internal components of the receptacle  100 . 
     The receptacle  100  can include a lifting mechanism to lift the lid  102  (i.e. to move the lid  102  from the closed position to the open position) and permit access to the chamber  101 - 2 . The lifting mechanism in the embodiment of  FIG. 1  is hands-free, including a pedal  113  connected to the lid  102  via a mechanical linkage  114  to engage with the lid  102  at an end  115  and actuate the lid  102  open and closed by rotating the lid  102  about a hinge  116 . Alternatively, the means of hands free actuation can be a solenoid and sensor or contact (e.g. a button, switch, proximity sensor or the like) that may also be paired with tension springs to assist in actuation. The hinge  116 , in the present embodiment, is affixed to the top rear of the shell  112  and/or the container  101 . 
     The receptacle  100  can also include a fan mounted within the chamber  101 - 2  and configured to circulate the air within the chamber  101 - 2 . In the present example, a fan  117  is embedded in an inner surface of the lid  102  (that is, a surface facing the chamber  101 - 2  when the lid  102  is closed). In other embodiments, as will be discussed in greater detail below, the fan  117  can be embedded in the inner wall  101 - 1 . The fan  117  preferably serves to cause air in the chamber  101 - 2  to flow directly over the evaporator  105 . In the present embodiment, the fan  117  is enabled to direct air over the evaporator  105  by way of a duct  118  (most clearly seen in  FIG. 2 ) having an inlet and an outlet. The fan  117  is placed to draw air into the duct  118  via the inlet, and expel the air from the outlet. As seen in  FIG. 2 , the outlet is disposed above the evaporator  105 , such that air returned to the chamber  101 - 2  from the duct  118  flows along the evaporator  105 . 
     In other embodiments, the duct  118  need not be embedded within the lid  102  or the walls of the container  101 . Instead, for example, the duct can be mounted on the inner wall  101 - 1  (and therefore protrude into the chamber  101 - 2 ). 
     In the present embodiment, the interface between the lid  102  and the container  101  is shaped so that a portion (in the present example, that portion representing a majority of the volume of the lid  102 ) of the lid  102  is nested within the upper walls of the container  101 . This is achieved by flaring the inner wall  101 - 1  outwards adjacent to the opening  101 - 3 , and tapering the bottom of the lid  102  inwards, creating a tapered lid-volume interface. This creates a tapered baffle  119  (see  FIG. 2 ) to deter air flow between the chamber  101 - 2  and the exterior of receptacle  100 , and to further enhance the seal of the lid  102  over the chamber  101 - 2  by reducing or preventing drafts and air leakage. A slot  120  (see  FIG. 2 ) can be provided around an edge of the lid  102  as a provision for attaching the gasket  103 . This nested configuration also provides an aesthetically pleasing appearance, reducing the visibility of the lid  102  to make it appear thin when closed, and hiding the gasket  103  from view. 
     The receptacle  100  can also include a removable bin  121  (see  FIGS. 2 and 3 ) having a loaded position within the chamber  101 - 2  for receiving and holding waste, and an unloaded position removed from the chamber  101 - 2  (e.g. for emptying waste). The removable bin  121  can hold a removable bag or liner  122  (see  FIG. 2 ). The removable bin  121  can include a retainer for gripping a portion of the bag  122 , such as one or more holes or clips. In the present embodiment, the retainer is provided by matching bag/liner retention holes  123 . In the embodiment shown in  FIG. 3 , holes  123  are provided on each of the four sides of the bin  121 . However, in other embodiments a variety of other hole arrangements can be employed. In operation, a portion of the bag  122  can be inserted into and retained by each hole  123  (see  FIG. 2 ) to aid in conforming the bag  122  to the shape of the bin  121 . The bin  121  can be sized and shaped to accommodate common plastic grocery bags. The bin  121 , in some embodiments, can also include perforations or texturing on an inner surface thereof to reduce adhesion of the bag to the bin  121 . 
     To aid in the loading and unloading of the bin  121  from the chamber  101 - 2 , the bin  121  can include a handle  124  with opposing ends affixed to opposing sides of the bin  121 . The handle  124  can be rotatable so as to permit raising the handle  124  to remove the bin  121  from the receptacle  100 , and lowering the handle  124  upon placement of the bin  121  within the chamber  101 - 2 . The bin  121  can include a handle stop  125  (see  FIG. 3 ) extending outwards from a wall thereof, so that the handle  124  rests in the upright position but does not obstruct the opening of the bin  121 . The handle  124 , in the present embodiment, is affixed to the bin  121  below an opposing pair of bag/liner retention holes  123 . In other embodiments, the handle  124  can be connected to the bin  121  in any other suitable way, or can simply be omitted. 
     The container  101  can include a guide structure within the chamber  101 - 2 . For example, as seen in  FIG. 1 , the inner wall  101 - 1  includes a protrusion  126  (two protrusions are provided in this embodiment, on opposite sides of chamber  101 - 2 ) extending into the chamber  101 - 2 . The bin  121  has a complementary indentation  127  (again, in the present embodiment two indentations  127  are provided) that matches the protrusion  126  in shape and engages with the protrusion  126  for aligning the removable bin  121  within the chamber  101 - 2 . The inner wall  101   s  is shaped and sized to facilitates air flow around the sides and underneath the bin  121  to aid convective airflow while also providing a flat surface for the bin  121  to rest (see indentations in the bottom of the inner wall  101 - 1  shown in  FIG. 1 ). 
     The receptacle  100  also includes a defrosting mechanism removing accumulated frost build up, which in the present embodiment is a heating element  128  (also referred to as a defrost pad) affixed to the evaporator  105 . Defrost pad  128  can be an electrically powered resistive strip, and serves to periodically raise the temperature of the evaporator  105  above the freezing point of water (in embodiments in which the temperature of the chamber  101 - 2  is brought below freezing). When the evaporator  105  is warmed by defrost pad  128 , any frost built up on the evaporator  105  melts and runs off of the evaporator  105 . 
     Formed into the bottom of the container  101  wall is a drainage trough  129  (most readily visible in  FIG. 2 ). In some embodiments, additional defrost pads can also be provided. For example, a drainage trough defrost pad  130  is affixed to wall of the drainage trough  129 . At the bottom of the trough  129  is a drain  131  extending from a drain inlet in the inner wall  101 - 1 , through the container  101  to a drain outlet in the outer wall  101 - 4 . The drain  131  directs defrost runoff fluid from the evaporator  105  (and from the chamber  101 - 2  more generally) to the exterior of the container  101 , in the present example via a P-trap  132  that runs into a drain pan  133 . In the present embodiment, the drain pan  133  is mounted over the compressor  106 . In other embodiments, however, the drain pan  133  can be placed in any other suitable location. The drain pan  133  may also be omitted (for example, the drain  131  may direct water into a wastewater line connected to a municipal network). 
     The receptacle  100  is powered by any suitable electrical power source, such as a standard home outlet through a power cord  134  (see  FIG. 2 ). Other power sources are also contemplated, such as batteries, solar panels and the like. In addition, it will be apparent to those skilled in the art that some embodiments (e.g. those employing absorption-based heat pumps) may not require electrical power. The receptacle is controlled via an electronic control unit  135 , also referred to as a controller, (e.g. a printed circuit board or other electronic device implementing any one of, or any suitable combination of thermostats, refrigeration timers and defrost timers). The control unit  135  samples temperature from inside the container  101  using a primary temperature or moisture sensor  136  to determine when to activate the heat pump. A defrost temperature sensor  137  may be located on the evaporator  105  which controls the defrost cycle. For example, the controller  135  can be configured to automatically enable the defrost pads  128  and  130  when the temperature of the evaporator (as measured via the sensor  137 ) rises above a predetermined threshold). Similarly, the controller  135  can be configured to automatically enable the heat pump to cool the chamber  101 - 2  when the temperature of the chamber  101 - 2  rises above another predetermined threshold (e.g. zero Celsius). 
     In operation, the receptacle  100  is provided with electrical power (if required, as noted above), for instance through the power cord  134 . The control unit  135  samples the temperature of the chamber  101 - 2  through the primary temperature sensor  136  and initiates operation of the compressor  106 . As a result, the evaporator  105  will become chilled, in the present embodiment to sub-zero (Celsius) temperatures. At the same time, the controller  135  is configured to enable the interior fan  117  to begin circulating air in the chamber  101 - 2 , including passing air over the evaporator  105  via the duct  118 . This will reduce the temperature of the air (and subsequently the waste) within the volume  101  to below the freezing point of water. 
     Independently of the above, a user may remove the bin  121  from the container  101  and affix a bag  122  into the bin  121 . This is accomplished by placing the bag  122  in the bin  121  and then forming the opening of the bag  122  around the top edges of the bin  121 . The bag  122  is then retained to this shape by inserting portions of the bag (e.g. the handles of a grocery bag) into the retention holes  123 . This is accomplished by rotating the handle  124  down and away from the retention holes  123  (as shown in dashed lines in  FIG. 3 ) and then retaining the portions of the top edges of the bag  122 , pulling the top edges taut around the outer edge of the bin  121 . The user may then rotate the handle  124  up again and deposit the bin  121  back into the container  101  via the opening  101 - 3 . In doing so, the protrusions  126  formed on the inner wall  101 - 1  of the container  101  serve to align the bin  121  by engaging with the indentations  127  formed into the bin  121 . The engagement between the above-mentioned guide structures seats the bin  121  within the container  101  consistently, ensuring proper air flow within the volume  101 . The interior fan  117  reduces the incidence of temperature gradients within the chamber  101 - 2  by actively circulating air throughout the chamber  101 - 2 . 
     The user may open the lid  102  by depressing the pedal  113 , which pivots the lid  102  about the hinge  116  via the mechanical linkage  114 . Alternatively, the user may manually lift or remove the lid  102 . The user may then deposit waste into the bag  122  contained within the bin  121  and then release the pedal  113  to close the lid  102  (or manually replace the lid  102 , in embodiments where the lid  102  is manually operated). 
     With waste contained within the bag  122 , inside the bin  121  in the loaded position in the container  101 , the cooling of the waste, preferably to temperatures below freezing, reduces or eliminates decomposition and the emission of foul odors. Further, a process of sublimation and deposition may occur in the chamber  101 - 2 , in which moisture from the waste is drawn into the cool, dry air in the chamber  101 - 2  and deposited on the colder surface of the evaporator  105 . Periodic activation of the defrost pads  128  and  130  by the control unit  135  melts the frost deposited on the evaporator  105  into water, which runs off into the drainage trough  129 . The water then exits through the drain  131  at the bottom of the trough, through the P-trap  132  and into the drain pan  133 . As noted earlier, in the present embodiment, the drain pan  133  is located on the compressor  106 , where the water evaporates into the atmosphere aided by the waste thermal energy from the compressor  106 . 
     When the bin  121  is full, the user may remove the bin  121  from the container  101  via the opening  101 - 3  and remove the bag  122 , now containing frozen waste, in the opposite order of installation (as detailed above) and then replace the bag  122  with a new one and place the bin  121  back into the container  101  for further waste collection. 
     The embodiment may also be operated without the bin  121  by placing a bag  122  directly in the chamber  101 - 2 . In some embodiments, the bag  122  may also be omitted, and waste (such as soiled diapers) may be placed directly into the chamber  101 - 2 . Such usage can increase the useable volume for waste within the chamber  101 - 2 , but is not presently preferred, due to the potential for reduced air flow within the chamber  101 - 2  and the potential for soiling of the evaporator  105  and the inner wall  101 - 1 . 
     Referring now to  FIGS. 4-6 , an actively cooled waste receptacle  200  according to another embodiment is illustrated. Components of the receptacle  200  similar to corresponding components of the receptacle  100  are numbered with the same reference numerals as introduced above in connection with the receptacle  100 , but with the suffix “a”. 
     Thus, the receptacle  200  includes a container  101   a  including an inner wall  101 - 1   a  defining a chamber  101 - 2   a  with an opening  101 - 3   a  and surrounded by an outer wall  101 - 4   a  (and joined to the outer wall  101 - 4   a  at the opening  101 - 3   a ). The opening  101 - 3   a  can be closed by a lid  102   a  having a gasket  103   a  that engages with an intermediate lip  104   a . In addition, the lid  102   a  and the inner wall  101 - 1   a  are tapered near the opening  101 - 3   a  so as to provide a baffle  119   a . The container  101   a  is supported by pylons  111   a , and contains an interior heat exchanger  105   a . In the present embodiment, the interior heat exchanger is an evaporator, and is a component of a heat pump including a compressor  106   a  and a condenser  107   a  connected to the evaporator  105   a  by fluid lines  108   a  and cooled by a condenser fan  109   a.    
     The receptacle  200  can include a fan  117   a  mounted within the chamber  101 - 2   a , as well as a duct  118   a  for directing air onto the evaporator  105   a . The evaporator  105   a  can include a defrost pad (not shown), and the chamber  101 - 2   a  includes a drain trough  129   a  (which can also include a defrost pad, not shown) for directing defrost runoff fluid to a drain  131   a  for removal of the fluid from the chamber  101 - 2   a  and collection in drain pan  133   a  via a p-trap  132   a.    
     A controller  135   a  can monitor chamber temperature via a sensor (not shown), and can also monitor the temperature of the evaporator  105   a  via another sensor (not shown). Based on the monitored state of the receptacle  200 , the controller  135   a  can automatically enable and disable the above-mentioned heat pump and defrost pads. 
     A bin  121   a  having bag retention holes  123   a  and a handle  124   a  can be loaded into the chamber  101 - 2   a  to collect waste within a bag (not shown) supported in the bin  121   a . The bin  121   a  can include indentations  127   a  for engaging with complementary protrusions  126   a  formed on the inner wall  101 - 1   a  of the container  101   a  to align the bin  121   a.    
     The receptacle  200  is configured as a freezer appliance integrated into a cabinet  201 , for example beneath a countertop  202 . The receptacle  200  may be integrated vertically, as with the receptacle  100 . Alternatively, as illustrated in  FIG. 4 , the heat pump components can be positioned beside or behind the container  101   a.    
     The compressor  106   a , condenser  107   a , and condenser fan  109   a  are mounted to a movable base  203 . A thermal exhaust duct  204  is provided to the outside of the cabinet  201  to allow heat to be expelled by the condenser  107   a . The base  203  is mounted on rails  205  that permit the base  203  to slide in and out of the cabinet  201 . The container  101   a , as noted above, is supported by the pylons  111   a  on the base  203 , but in other embodiments, the container  101   a  may sit directly on the base  203 . The configuration of supports for the container  101   a  may be dependent on the depth of the cabinet  201 . The sliding motion of the base  203  may be passive and performed by the user, or active and performed via an electromechanical mechanism (e.g. a linear actuator activated by a switch, proximity sensor or the like). 
     Alternatively, the base  203  may be linked to the cabinet  201  by a hinge and pivot outward, also actuated by the user or performed via electromechanical means. In further variations, the base  203  may be linked to the cabinet  201  by both sliding rails  205  and a hinge so as to protrude and then pivot. 
     In the present embodiment, the lid  102   a  is retracted upwards (towards the countertop  202  and away from the opening  101 - 3   a ) by a retractor  206 , such as a solenoid actuator, that is activated by a switch, such as a proximity sensor  207  (see  FIG. 6 ). The retractor  206  acts to lift the lid  102   a  slightly to allow the gasket  103   a  to disengage from the intermediate lip  104   a  of the container  101   a , allowing the container  101   a  to slide out from the cabinet  201  unimpeded. Alternatively, mechanical linkages (such as sliding cams and push rods) can be used to lift the lid  102   a  with the motion of the base  203 . 
     Alternatively, the lid  102   a  may be accessible via a cutout (not shown) in the cabinet countertop  202 , in which case the lid  102   a  would need only pivot to open (similarly to the movement of the lid  102  described earlier in connection with  FIGS. 1-3 ), revealing the chamber  101 - 2   a.    
     The exterior of the receptacle  200  that faces the outside of the cabinet  201  can have a cover or shell, which may be arranged to be flush with adjacent cupboards when the receptacle  200  is closed. For example, the receptacle  200  can include a cabinet face  208  fixed to the front of the container  101   a  so as to blend in directly with the adjacent cabinets. The face  208  can include one or more of the above-mentioned sensor  207 , a handle  209 , or other structures permitting a user to open the receptacle  200  (e.g. a pedal, not shown). 
     Operation of the receptacle  200  is similar to that of the receptacle  100 . Power is provided (if required, e.g. via an electrical cord, not shown), the heat pump chills the chamber  101 - 2   a , the interior fan  117   a  circulates air and the bin  121   a  is lined with a bag  122   a.    
     In contrast to the operation of the receptacle  100 , however, to access the receptacle  200  for provisional waste storage, one or more of the sensor  207 , handle  209 , pedal or the like is activated. Such activation triggers the solenoid  206  (e.g. the controller  135   a  can detect the activation and cause the solenoid  206 ) to disengage the lid  102   a  from the opening  101 - 3   a  and permit the base  203  to slide out from the cupboard  201  to expose the container  101   a . The user may then deposit waste within the bag contained within the bin  121   a  and then slide and/or pivot the container  101   a  back into the cabinet  201 . Alternatively, the user may remove the bin  121   a  from the container  101   a  and place it on the countertop  202  for collection of waste, re-inserting the bin  121  when they are finished. Once the container  101   a  is contained within the cabinet  201 , the lid  102   a  re-engages (e.g. the controller  135   a  can detect the re-insertion of the container  101   a  and cause the solenoid  206  to move the lid  102   a  to the closed position), sealing the opening  101 - 3   a . Once waste is contained within the interior volume, the process of freezing, sublimation, and deposition as described above takes place to retard odors and reduce or eliminate bacteria growth and decomposition of the waste. As also described earlier, automatic defrost can be initiated periodically to keep the evaporator  105  free from excessive frost build-up. 
     Referring now to  FIGS. 7-9 , an actively cooled waste receptacle  300  according to another embodiment is illustrated. Components of the receptacle  300  similar to corresponding components of the receptacle  100  are numbered with the same reference numerals as introduced above in connection with the receptacle  100 , but with the suffix “b”. 
     Thus, the receptacle  300  includes a container  101   b  including an inner wall  101 - 1   b  defining a chamber  101 - 2   b  with an opening  101 - 3   b  and surrounded by an outer wall  101 - 4   b  (and joined to the outer wall  101 - 4   b  at the opening  101 - 3   b ). The opening  101 - 3   b  can be closed by a lid  102   b  having a gasket  103   b  that engages with an intermediate lip  104   b . The lid  102   b  moves between a closed position and an open position via a hinge  116   b . In addition, the lid  102   b  and the inner wall  101 - 1   b  are tapered near the opening  101 - 3   b  so as to provide a baffle  119   b . The container  101   b  contains an interior heat exchanger  105   b , which is a component of a heat pump also including an exterior heat exchanger  107   b  cooled by a fan  109   b . The receptacle  300  can include a fan  117   b  mounted within the chamber  101 - 2   b , for directing air onto the heat exchanger  105   b.    
     A controller  135   b  can monitor chamber temperature via a sensor (not shown), and can also monitor the temperature of the heat exchanger  105   b  via another sensor (not shown). Based on the monitored state of the receptacle  300 , the controller  135   b  can automatically enable and disable refrigeration and defrosting functions of the receptacle  300 . The controller  135   b  and other components can be powered via an electrical cord  134   b , or any other suitable power source. 
     A bin  121   b  having bag retention holes  123   b  and a handle  124   b  can be loaded into the chamber  101 - 2   b  to collect waste within a bag (not shown) supported in the bin  121   b . The bin  121   b  can include an indentation  127   b  for accommodating the heat exchanger  105   b  and fan  117   b , and also for assisting in aligning the bin  121   b  within the chamber  101 - 2   b.    
     The receptacle  300  is configured as a freezer appliance sized to fit on a counter (e.g. a kitchen counter). The interior heat exchanger  105   a  is a component of a thermoelectric (rather than vapor compression as in the previous embodiments) heat pump. The interior heat exchanger  105   b  is therefore implemented as a heatsink, and the heat pump also includes a thermoelectric device  301  employing the Peltier effect and having a hot side and a cold side. As will be apparent to those skilled in the art, the hot side and cold side of the device  301  are switchable, and the state of each side depends on whether the receptacle  300  is being refrigerated or defrosted, as described below. 
     The exterior heat exchanger  107   b  is also a heatsink, and can be covered by a protective cover  305 . The heatsinks  105   b  and  107   b  are plate and fin heatsinks. In other embodiments, the heatsink  107   b  can be replaced by a liquid-cooled heatsink (e.g. having cooling block mounted on device  301  and circulating fluid therethrough, with the fluid being pumped through a radiator to dissipate heat collected by the fluid). In other embodiments, the heat pump of receptacle  300  may be replaced with a vapor compression heat pump such as those discussed earlier. 
     The bin  121   b  is provided in the form of a removable basket (and is therefore also referred to as a basket  121   b ). The basket is made from perforated or meshed sheet material (e.g. plastic, aluminum, or the like) to allow air to flow through, improving the cooling effect on the contents of the basket  121   b . The basket  121   b  can be shaped to guide the convective airflow throughout the interior volume. Ducting or air-flow channels (not shown) may also be shaped into the walls of the lid  102   b  and basket  121   b . This basket has a flat rim  307  that allows it to sit on the intermediate lip  104   b  of the container  101   b . This suspends the remainder of the basket within the container  101   b , allowing air to also circulate around and underneath the basket  121   b  and its contents. The basket  121   b  contains two cutout handles  308  to allow the removal of the basket  121   b  from the container  101   b . A portion of a bag can be retained within these cutout handles  308  to conform the bag to the shape of the basket  121   b  (that is, the handles  308  can perform the same function as the retention holes  123  and  123   a  discussed earlier). 
     The lid  102   b  may be opened and closed via a tab  309 . Alternatively, the lid  102   b  can be operated via a contact (a switch, button, or the like, not shown) or a proximity sensor (not shown) to actuate the lid  102   b  open by means of a solenoid  310  or other electromechanical means. 
     The receptacle  300  can include a removable drip cup  311  positioned below the interior heat exchanger  105   b  to collect defrosted water. The drip cup  311  made be made of silicon or other pliable material to allow ice to be easily removed therefrom. 
     The receptacle  300  is operated by first providing power (e.g. via cord  134   b ). The control unit  135   s  initiates the thermoelectric device  301 . As a result, the interior heat exchanger  105   b  is cooled below a threshold temperature (preferably a sub-zero Celsius temperature). At the same time, the interior fan  117   b  begins circulating air throughout the chamber  101 - 2   b . This will reduce the temperature of the air (and subsequently the waste) within the chamber  101 - 2   b  to below freezing. Independently of this, the user may remove the basket  121   b  and install a bag into the basket  121   b  and around the flat rim  307 , inserting a portion of the bag through the cutout handles  308  to conform to the shape of the basket  306 . 
     To access the receptacle  300 , the user shall can lift the lid  102   b  via the tab  309  or the above-mentioned switch or proximity sensor. The user may then deposit waste within the bag and close the lid  102   b . Once waste is contained within the chamber  101 - 2   b , the process of freezing, sublimation, and deposition begins to retard odors and reduce or eliminate bacteria growth and decomposition of the waste as described earlier. 
     Periodically, the controller  135   b  can control the thermoelectric device  301  to switch the cold and hot sides thereof, to heat (rather than cool) the interior heat exchanger  105   b  for defrosting. This will cause the interior heat exchanger  105   b  to warm, melting any frost buildup into water. This water will drip into the drip cup  311  and may freeze into ice. This cup can be emptied periodically (e.g. by a user). When the basket  121   b  is full, the user may remove the bag containing frozen waste and then replace the bag with a new one. 
     Referring now to  FIGS. 10-12 , an actively cooled waste receptacle  400  according to another embodiment is illustrated. Components of the receptacle  400  similar to corresponding components of the receptacle  100  are numbered with the same reference numerals as introduced above in connection with the receptacle  100 , but with the suffix “c”. 
     Thus, the receptacle  400  includes a container  101   c  including an inner wall  101 - 1   c  defining a chamber  101 - 2   c  with an opening  101 - 3   c  and surrounded by an outer wall  101 - 4   c  (and joined to the outer wall  101 - 4   c  at the opening  101 - 3   c ). The opening  101 - 3   c  can be closed by a lid  102   c  having a gasket  103   c  that engages with an intermediate lip  104   c . In addition, the lid  102   c  and the inner wall  101 - 1   c  are tapered near the opening  101 - 3   c  so as to provide a baffle  119   c . The container  101   c  contains an interior heat exchanger  105   c . In the present embodiment, the interior heat exchanger is an evaporator, and is a component of a heat pump including a compressor  106   c  and a condenser  107   c  connected to the evaporator  105   c  by fluid lines  108   c  and cooled by a condenser fan  109   c.    
     The receptacle  400  can include a fan  117   c  (the present embodiment includes two fans  117   c ) mounted within the chamber  101 - 2   c , each pulling air into a duct  118   c  for directing air onto the evaporator  105   c . The evaporator  105   c  can include a defrost pad  128   c  (two pads  128   c  are shown), and the chamber  101 - 2   c  includes a drain trough  129   c  (which can also include a defrost pad, not shown) for directing defrost runoff fluid to a drain for removal of the fluid from the chamber  101 - 2   c  and collection in drain pan  133   c  via a p-trap  132   c.    
     A controller  135   c  can monitor chamber temperature via a sensor (not shown), and can also monitor the temperature of the evaporator  105   c  via another sensor (not shown). Based on the monitored state of the receptacle  400 , the controller  135   c  can automatically enable and disable the above-mentioned heat pump and defrost pads  128   c . A removable bin  121   c  having bag retention holes  123   c  and a handle  124   c  can be loaded into the chamber  101 - 2   c  to collect waste within a bag  122   c  supported in the bin  121   c.    
     The receptacle  400  is configured as a standalone freezer appliance, sized appropriately for industrial or commercial use in that its overall dimensions are suitable for use in the garbage room of an apartment complex, in a hospital/nursing home setting or other facility requiring provisional waste storage. 
     The container  101   c  extends to a base  110   c  of the embodiment. Instead of being vertically integrated, the compressor  106   c , condenser  107   c , and other refrigeration components are located behind the container  101   c  (as seen in  FIGS. 11A and 11B ). The lid  102   c  of the receptacle  400  may include a deposit hatch  401  (including a gasket for sealing against the lid  102   c  and a tapered portion for forming a similar baffle to baffle  119   c ), activated through a proximity sensor  407 , pedal, switch, tab or the like, and actuated via a solenoid or any other suitable mechanism. The lid  102   c  may employ a gas spring, spring or other biasing mechanism (not shown) to prop the lid  102   c  open. 
     The container  101   c  is accessible through a secondary opening in the form of an insulated door  402  on the front of the receptacle  400 , which swings open on door hinges  403 . The door  402  has a door gasket  404  to seal the container  101   c  from the front, and can taper similarly to the lid  102   c  to form a baffle similar to baffle  119   c  with container  101   c . The door  402  may be kept shut by a door latch  405  or magnet and can include a door handle  406  or other mechanism for opening the door  402 . The door  402  may be configured as a double door, pivoting off of either side of the container  101   c . In such embodiments the double doors would latch to each other. 
     In contrast to the bins of the previously discussed embodiments, removable bin  121   c  is implemented as a wheeled cart (and is therefore also referred to as a cart  121   c ). The cart  121   c  has walls, an open top, and locomotive devices such as castor wheels  408  on the bottom. The shape of the cart  121   c  conforms to the shape of the chamber  101 - 2   c , with some allowance for air circulation. As noted above, the cart  121   c  can also include a handle  124   c . In the present embodiment, two handles  124   c  are provided that also act, in combination with a protruded fulcrum feature  411 , as pivot grips  412  that allow the cart  121   c  to pivot about an axis to facilitate dumping the contents of the cart  121   c  into a larger collection bin or chute. 
     The receptacle  400  includes a guide structure for aligning the cart  121   c . Rather than the protrusions  126  and indentations  127  mentioned earlier, however, the container  101   c  defines raceways  413  for receiving the caster wheels  408 . Further, at the bottom of the container  101   c  along the interface with the door  402  is a ramp  414  to facilitate rolling the cart  121   c  into and out of the container  101   c . The cart  121   c  itself may also have a door (not shown) to allow easy unloading of heavy bags full of waste. 
     The receptacle  400  can include a volume sensor (e.g. a fill level proximity sensor  415 ), a weight sensor (e.g. a load sensor disposed within one or both of the raceways  413 ), or a combination thereof, permitting the controller  135   c  to determine the current fill level and/or weight of the bin  121   c . In other embodiments, the above-mentioned sensors may be mounted on the cart  121   c  itself. The receptacle  400  can include an output device for indicating how full the cart  121   c  is. The output device can include any one of, or any suitable combination of, a light  417 , a display panel  418 , a speaker for generating an audible signal, a (wired or wireless) network interface integrated with or otherwise connected to the controller  135   c , and the like. 
     In the case of the above-mentioned network interface, the controller  135   c  may be connected to a network and communicate with a central hub through a smartphone or computer application whereby a multitude of other receptacles may be connected, all displaying their current level of waste. 
     The receptacle  400  is operated by first providing power to the unit. If the receptacle  400  is network enabled, it will connect to the network at this time and initiate a flow of information. The heat pump is then initiated (e.g. by the controller  135 ), cooling the container  101   c  to below a threshold (e.g. 0 degrees Celsius). 
     Independent of this, the user may unlatch the door  402  of the receptacle  400  and roll out the cart  121   c , making use of the ramp  414  for this purpose. Once removed, the user may insert a bag  122   c  into the cart  121   c , making use of the retention features  123   c  to conform the bag  122   c  to the internal shape of the cart  121   c . The user may then roll the cart  121   c  back into the container  101   c  and close the door  402 , using the latch  405  to retain it shut. 
     In regular usage, if the user has a small item to deposit (such as a diaper or small bag of refuse) they may use the deposit hatch  401  located within the lid  102   c  to quickly deposit an item. The user may actuate the deposit hatch  401  by use of the proximity sensor  407 . This will activate the mechanism that opens the deposit hatch  401  to allow the user to deposit the refuse. The refuse will fall into the bag  122   c  contained within the cart  121   c , within the volume  101 . 
     If the user has a larger item to deposit, such as a soiled bedsheet, they may lift the lid  102   c  up entirely. This may be done by hand or using another pedal, proximity sensor, or contact. The lid  102   c  may be kept open by a gas spring cylinder, stopper, tension spring, or other mechanism to allow the user to deposit the larger item into the bag  122   c  within the cart  121   c.    
     At such a time as the waste within the cart  407  meets a predetermined volume or weight, as determined by the fill level proximity sensor  415 , load sensor  416 , or other means, the controller  135   c  is configured to communicate that it is at capacity and requires emptying. Such communication may be achieved by activating any one or more of the indicator light  417 , the display panel  418 , or any other output devices that are present. If linked to a network, the controller  135   c  can communicate via the network (e.g. to a client computing device such as a smartphone) that the receptacle  400  requires emptying. Such network communication permits, in the case of a plurality of receptacles  400  deployed throughout a health care facility apartment complex or other site, a user to plan their route based on which receptacles  400  are indicating that they require emptying. 
     Once waste is contained within the chamber  101 - 2   c , the process of freezing, sublimation, and deposition begins to reduce or eliminate odors and stall bacteria growth and decomposition of the waste as in the first embodiment. As described earlier, automatic defrosting can be initiated periodically by the controller  135   c  to keep the evaporator  105   c  free from excessive frost build-up. 
     Other variations to the above embodiments are also contemplated. For example, the use of thermoelectric devices or other refrigeration methods are interchangeable with the refrigeration means described above. Alternative means of defrost such as electrical impulse, ice phobic coatings, and vibrations, or other means yet devised can be employed. Alternative means of power such as photovoltaic and wind turbines may be employed. Temperatures may be adjusted to above the freezing point of water for some applications. 
     Changes in size, shape, and appearance to accommodate different commercial applications such as restaurants, food trucks, nursing homes, hospitals, apartment complexes, and public spaces may be made. 
     Further embodiments can include two or more distinct compartments rather than a single chamber  101 - 2 . At least one, and possibly (though not necessarily) all of the compartments can be refrigerated as described above. The number of distinct compartments can vary based on the number of different waste items requiring sorting. Each non-refrigerated volume is contained by a removable bin that holds provisions such as clips or holes to retain a waste bag to the shape of the bin. Each non-refrigerated compartment may also contain a lid, opening, trap door, or simple opening, and a means to access such as a pedal, linked to the lid by a mechanical linkage, a proximity sensor or contact motivated by electromechanical means, similar to existing multi-compartment waste receptacles found in the marketplace. 
     In other embodiments, the removable bin (e.g. the cart  121   c ) may tilt outwards rather than being removed entirely from the container  101   c ). Other modifications may also be made to the embodiments described herein; for example, an outdoor implementation of an actively cooled waste receptacle may be provided as an insulated dumpster, with a sufficiently robust exterior to resist damage from animals and the elements. 
     The scope of the claims should not be limited by the embodiments set forth in the above examples, but should be given the broadest interpretation consistent with the description as a whole.