GB2463023A

GB2463023A - A refrigerator for degradable waste

Info

Publication number: GB2463023A
Application number: GB0815615A
Authority: GB
Inventors: John Rush
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-08-28
Filing date: 2008-08-28
Publication date: 2010-03-03
Also published as: GB0815615D0

Abstract

A refrigerator unit for degradable waste comprising at least one heat exchanger 7 mounted above the top of a waste material container 1. The heat exchanger(s) 7 is positioned to dissipate the majority of heat externally to any enclosure for the container thereby eliminating the heating of the waste storage bin enclosure, and to allow cool air produced by the heat exchanger to sink by convection to said stored waste. Preferably the refrigeration unit comprises a separate heat 7 and cooling 2 heat exchangers that are separated by a dividing surface 8. A duct may be positioned between the waste container and the cooling heat exchanger to guide cooled air to the top of the waste container. The refrigeration unit may be regulated by one or more temperature sensors mounted to measure the temperature of the waste container or the external temperature outside of the enclosure housing the waste container.

Description

REFRIGERATOR FOR DEGRADABLE WASTE

BACKGROUND

A number of patents have been filed for devices which refrigerate degradable waste, for example organic material or kitchen waste. The reasons for treating waste so is to prevent the process of decay whilst the waste is stored in locations where people live or work, since this is unpleasant and unsanitary. The devices revealed however consist of conventional waste containers to which has been added some type of refrigeration unit, which is often placed under the storage container. Although this would appear to function, such a system has several disadvantages. The first is concerned with the thermodynamics of the general arrangement. It is common for such waste to be stored in a container which is itself housed in an enclosure, the enclosure being not ventilated to the general environment for obvious reasons. In a domestic situation, for example, waste is often stored in a bin housed in a closed cupboard under the sink. A refrigeration unit is a device for moving heat from a cooling unit, and dispersing that heat through a heating unit. Extra heat generated by the process itself, usually amounting to about 30% of the heat moved, is also dispersed through the heating unit. In a conventional domestic refrigerator, the heating coils are usually on the rear of the unit where they are not enclosed and can disperse heat into the general environment. If a refrigeration unit is placed in a closed housing, it will disperse more heat into the closed environment than is removed from the inside of the refrigerator. A stored waste refrigerator designed in this way will therefore heat the closed environment as it tries to cool the waste storage space within the closed environment. This is clearly contradictory, and the process would be inherently inefficient. A further disadvantage of such a system is that the refrigeration unit, in close proximity to the waste storage unit, is likely to become contaminated very quickly, leading to further inefficiencies in its operation.

DRAWINGS

Figure 1 shows the cooling unit 2 of a refrigeration unit mounted above a waste storage bin 1.

Figure 2 shows the cooling unit 2 of a refrigeration unit mounted above a waste storage bin 1, with an intermediate duct 4.

Figure 3 shows the dissipating heat exchanger 7 and the cooling unit, with a separating surface 8.

Figure 4 shows an alternative position for the dissipating heat exchanger 7.

DESCRIPTION.

The invention revealed is a device for the refrigeration of waste which is organic or largely organic, and so may degrade biologically; but is temporarily stored in accomodation where people live or work. It has particular application to the domestic situation where kitchen waste is often stored in the kitchen for some time prior to collection. The invention avoids the disadvantages cited above and has further advantages in terms of reliability, installation and cost. In a closed environment such as the space for storing kitchen waste, there is likely to be very little movement of air. it is therefore possible to produce cooled air above the stored waste, and by natural convection, this cooled air will sink and permeate the stored waste.

This makes it possible to install the refrigeration unit above the stored waste, as a separate unit from the waste storage container itself. Because the refrigeration unit is above the stored waste, and also separate and therefore not subject to the requirements to be moved so that the waste can be removed, the heating unit of the refrigerator can more easily be installed such that it can disperse the heat produced to the outside of an enclosure in which the waste container is kept. Further, because the refrigeration unit is above the stored waste, it is much less subject to contamination with waste material which would otherwise occur with the refrigeration unit under the waste container.

Figure 1 shows a general arrangement. There is a waste storage bin 1, which is not closed at the top, and in practice is probably lined with a disposable plastic bag.

The cooling unit of the refrigerator 2, in this case a simple tubular device, is positioned higher than the top of the waste storage bin, and in this case, approximately over the top of the bin. Several of the general components of the refrigeration unit, such as the compressor, throttle valve and controls, are contained in a housing 3. The cooling unit 2 will cool the air above the waste bin, and assuming that there are no other overriding influences, this cooled air will sink into the waste bin below. Given that the stored waste will be at least slightly loose, the cool air will permeate the stored waste, and the contents of the bin will cool from the bottom upwards.

The waste refrigeration may be improved by installing a guidance surface or duct between the cooling unit and the open top of the waste storage unit, as shown in figure 2. The duct 4 surrounds the cooling unit 2 and guides the sinking cooled air to the top of the waste bin via an opening 5. The inclusion of the duct enables the cooling unit to be larger in plan view than the bin opening, so that more cooling can be provided, and it allows more versatility in the placement of the cooling unit above the bin. The ducting is designed such that warm air rising from the bin enclosure can reach the cooling unit, by inclusion of the vent slots 6 for example. The sinking cooled air will displace warmer air from the enclosure, so that this provides an efficient circulation of air for the refrigeration process.

The waste refrigeration unit must include a heating unit as a heat exchanger with the environment, so as to disperse the heat removed from the cooling unit and the heat produced by the process itself. In terms of refrigeration efficiency, the heating unit would be outside the enclosure which contains the waste bin, but this option may make design and installation of the device difficult. For ease of design, manufacturing and installation, the heating unit would be within the enclosure for the waste storage bin, but in this case it must be thermally separated from the cooling unit and sufficiently ventilated to the external environment. Figure 3 illustrates an arrangement in which the heating unit 7 is mounted above the cooling unit 2. Another option is to place the heating unit to one side of the cooling unit. Although in the case shown in figure 3 natural convection will tend not to mix the warm and cool air flows, there is also a separating surface 8 between the heating and cooling units. This surface 8 can completely seal off the upper and lower regions over the whole of the enclosure which contains the waste storage bin. In figure 3 the surface is shown partly cut away, to illustrate the position of the surface in relation to the other components 2 and 7. If the heating coil is placed to one side of the cooling unit, the separating surface can be arranged as shown in figure 4. In this case the separating surface separates the heating and cooling units from each other, and the heating unit from the waste bin enclosure.

The separating surface is again partially cut away on the left side to illustrate the position of the cooling unit.

If the waste bin is located in a floor level cupboard in a kitchen, which is often the case, the heating unit can be ventilated to the environment through a grill in the front surface of the cupboard. In such a situation, the front surface of the enclosure is often the only surface available. The heat dissipated into the environment by the refrigeration unit may itself be useful if the heat dissipation exchanger is placed under a thermally conductive horizontal surface such as the drying area next to a sink. In this case the heat will assist in drying items placed on the surface.

It may be assumed that the waste refrigerator will not operate continuously, but rather in an ON I OFF mode as in a conventional refrigerator. That being so, it will require some kind of regulatory control system. In a conventional refrigerator the unit is usually controlled by the signal from a temperature sensor within the cold space of the refrigerator. The requirements for cooling waste material will be far less stringent than those for the storage of fresh food, so that temperature control can be far less precise. It would probably be impractical to install a temperature sensor inside the waste storage unit, since it will probably have to be moved to remove the waste material. One solution is to have a temperature sensor mounted in the enclosure such that it is in contact with the outside of the waste bin when the waste bin is positioned in the enclosure. This could be done relatively easily if the sensor were to be in contact with the bottom surface of the bin, and it will not interfere with the normal use of the bin. Given the nature of the material to be cooled, such a system is likely to be subject to wide variations in operation. An alternative solution is to automatically regulate the refrigeration unit according to the temperature outside the waste bin enclosure, since this will have the greatest overall effect on the average temperature of the stored waste material. Any such automatic regulation can be combined with a manual control which the user can adjust according to their own preference.

Claims

REFRIGERATOR FOR DEGRADABLE WASTECLAIMS1 A refrigeration unit for the cooling of stored waste in which the heat exchanger which extracts heat from the environment is mounted above the top of the waste material container such that cooled air produced by said heat exchanger will sink by convection and may thereby permeate and cool said stored waste, and in which the heat exchanger which dissipates heat is positioned and ventilated such that it is able to dissipate heat mainly in the environment external to any enclosure for the container of said stored waste.
2 A refrigeration unit for the cooling of stored waste as in claim 1 in which there is a separating surface designed to divide any enclosure for the container of said stored waste into a cool space containing the extraction heat exchanger and another space containing the dissipating heat exchanger.
3 A refrigeration unit for the cooling of stored waste as in any of the previous claims in which, between the waste container and the cooling heat exchanger, there is an intermediate surface or duct intended to guide cooled air from said cooling heat exchanger to the top of said waste container.A refrigeration unit for the cooling of stored waste as in any of the previous claims which may be automatically regulated by one or more temperature sensors mounted so as to be in contact with an outside surface of the normally positioned waste container.6 A refrigeration unit for the cooling of stored waste as in any of the previous claims which may be automatically regulated by one or more temperature sensors mounted so as to sense the temperature of the environment outside an enclosure housing the waste container.