EP3521735A1

EP3521735A1 - A refrigeration apparatus and a method for defrosting a refrigeration apparatus

Info

Publication number: EP3521735A1
Application number: EP18154482.6A
Authority: EP
Inventors: Yusuf AK; Nevzat YALIN; Erol Özen
Original assignee: Vestel Elektronik Sanayi ve Ticaret AS
Current assignee: Vestel Elektronik Sanayi ve Ticaret AS
Priority date: 2018-01-31
Filing date: 2018-01-31
Publication date: 2019-08-07
Also published as: TR201802606A2

Abstract

A refrigeration apparatus (202) comprises a condenser (224); an evaporator (222) in fluid communication with the condenser (224); and a heat scavenger (230). The heat scavenger (230) is constructed and arranged to capture heat from the condenser (224) and to transfer the heat to a part of the refrigeration apparatus (202) that is susceptible to frosting for defrosting said part.

Description

Technical Field

The present disclosure relates to a refrigeration apparatus and a method for defrosting a refrigeration apparatus.

Background

So-called frost-free refrigeration apparatus, such as freezers and refrigerators and the like, employ various complex methods for preventing a build-up of ice. One example of such a method is periodically heating the freezer or refrigerator to melt any ice that may have formed inside. This process can be wasteful and inefficient

Summary

According to a first aspect disclosed herein, there is provided a refrigeration apparatus comprising: a condenser; an evaporator in fluid communication with the condenser; and a heat scavenger constructed and arranged to capture heat from the condenser and to transfer the heat to a part of the refrigeration apparatus that is susceptible to frosting for defrosting said part.
This allows the heat scavenger to recover waste heat from the condenser, which would normally be transferred to the environment of the refrigeration apparatus, and use the heat to defrost a part of the remigration apparatus if it freezes. An external heat source is not required. The heat scavenger therefore provides an energy efficient way to defrost the part of the refrigeration apparatus.
In an example, said part is the evaporator.
In an example, the refrigeration apparatus comprises a controller, the controller being configured to activate the heat scavenger to capture and transfer heat from the condenser to a part of the refrigeration apparatus that is susceptible to frosting.
In an example, the refrigeration apparatus comprises a temperature sensor for providing a measure of the temperature of a part of the refrigeration apparatus that is susceptible to frosting, wherein the controller is configured: to obtain a measure of the temperature of the part of the refrigeration apparatus that is susceptible to frosting; compare the obtained temperature with a first predetermined threshold temperature; and activate the heat scavenger when the obtained temperature is or decreases below the first predetermined threshold temperature.
In an example, the controller is configured: to obtain a measure of the temperature of the part of the refrigeration apparatus that is susceptible to frosting; compare the obtained temperature with a second predetermined threshold temperature that is higher than the first predetermined threshold temperature; and if the heat scavenger is activated, deactivate the heat scavenger when the temperature of the part is or increases above a second predetermined threshold temperature.
In an example, the refrigeration apparatus comprises a plurality of temperature sensors, wherein the controller is configured to obtain an average of the temperatures sensed by the plurality of temperature sensors.
In an example, the refrigeration apparatus comprises a heater constructed and arranged to heat the condenser, wherein the controller is configured to activate the heater if the controller determines that a compressor of the condenser is off whilst the heat scavenger is activated.
In an example, the heat scavenger comprises: one or more pipes conveying a heat transfer fluid for transferring heat from the condenser to the part of the refrigeration apparatus that is susceptible to frosting; and a valve constructed and arranged to open to allow flow of the heat transfer fluid and to close to prevent flow of the heat transfer fluid.
According to a second aspect disclosed herein, there is provided a method of defrosting a part of a refrigeration apparatus, the method comprising: activating a heat scavenger to capture heat from a condenser of the refrigeration apparatus and to transfer the heat to a part of the refrigeration apparatus that is susceptible to frosting for defrosting said part.
In an example, said part is an evaporator of the refrigeration apparatus.
In an example, the heat scavenger is activated by a controller.
In an example, the method comprises: obtaining a measure of the temperature of the part of the refrigeration apparatus that is susceptible to frosting; comparing the obtained temperature with a first predetermined threshold temperature; and activating the heat scavenger when the obtained temperature is or decreases below the first predetermined threshold temperature.
In an example, the method comprises: obtaining a measure of the temperature of the part of the refrigeration apparatus that is susceptible to frosting; comparing the obtained temperature with a second predetermined threshold temperature; and if the heat scavenger is activated, deactivating the heat scavenger when the temperature of the part is or increases above a second predetermined threshold temperature.
In an example, the method comprises activating a heater that to heat the condenser if a compressor of the condenser is off whilst the heat scavenger is activated.
In an example, the method comprises: activating the heat scavenger by opening a valve to allow a heat transfer fluid to flow to transfer heat from the condenser to the part of the refrigeration apparatus that is susceptible to frosting; and deactivating the heat scavenger by closing the valve to stop the heat transfer fluid from flowing to prevent heat transfer from the condenser to the part of the refrigeration apparatus that is susceptible to frosting.

Brief Description of the Drawings

To assist understanding of the present disclosure and to show how embodiments may be put into effect, reference is made by way of example to the accompanying drawings in which:

Figure 1 shows schematically an example of a known refrigeration apparatus; and
Figure 2 shows schematically an example of a refrigeration apparatus and a heat scavenger according to aspects described herein.

Detailed Description

Refrigeration apparatus, such as for example frost-free freezers and refrigerators and the like, prevent a build-up of ice, using relatively complex or inefficient methods. One such method is heating parts of the refrigeration apparatus to allow or cause any ice that may have formed to melt. However, this method consumes a large amount of power and is inefficient, leading to defrosting taking a long time.
Figure 1 shows schematically an example of a known refrigeration apparatus 100 for implementing a vapour-compression refrigeration cycle to cool a space 110. Specifically, in this example the vapour-compression refrigeration cycle (described in more detail below) is implemented to cool a freezer portion 111 of the space 110 to below 0°C. Other portions of the space 110 will be cooled too depending on the temperature of the freezer portion 111 and the layout of the refrigeration apparatus 100. In any case, the freezer portion 111 represents a subsection of the space 110 in which substances such as foodstuffs may be placed to freeze them. More generally, the vapour-compression refrigeration cycle may be used to cool a space 110 of a refrigeration apparatus 100 even if the refrigeration apparatus 100 does not have a freezer portion as such.
The refrigeration apparatus 100 comprises a closed circuit of tubing 120 containing a selected refrigerant for cooling the interior of a space 110 (e.g. a foodstuff-storing portion of a refrigeration apparatus). Specifically, the circuit of tubing 120 includes an internal section 122 located within the freezer portion 111 and an external section 124 located outside the space 110.
The refrigerant is selected having a temperature of vaporisation such that it will vaporise in the internal section 122 as it absorbs heat from the interior of the freezer portion 111. For this reason, the internal section 122 may also be referred to as an evaporator 122.
A compressor 123 is provided to compress the vaporised refrigerant, which raises its temperature significantly. The high pressure, high temperature refrigerant vapour passes from the compressor 123 through the "hot" external section 124 of the circuit 120. The external section 124 acts as a condenser in the refrigeration cycle, transferring heat to the environment (e.g. the room in which the refrigeration apparatus 100 is located). A heatsink or fan may be provided to improve the transfer of heat. The transfer of heat causes at least some of the refrigerant vapour in the external section 124 to condense back to a liquid form.
The high pressure refrigerant, now cooled and at least partially in liquid form, passes to an expansion valve 121 which reduces the pressure of the refrigerant, causing it to expand and therefore cool. The low pressure low temperature refrigerant then passes through the evaporator 122 within the freezer portion 111, acting as an evaporator in the refrigeration cycle, to absorb heat from the interior of the freezer portion 111. As a result, the cool refrigerant liquid passing through the evaporator 122 vaporises before passing on to the compressor 123 to complete the refrigeration cycle.
The compressor 123 may be driven by a low power DC motor, selected according to the refrigerant vapour pressure and temperature required in the external section 124 of the circuit and the rate of cooling required by the evaporator 122 of the circuit.
Because of the low temperatures generated within the freezer portion 111 by the evaporator 122, humidity from the air may freeze to the evaporator 122, causing an ice layer to build up over time. The ice build-up (also called "frost") on the evaporator 122 and/or in other parts of the refrigeration apparatus 100 is undesirable because it reduces the efficiency of the refrigeration apparatus 100 and occupies space within the freezer portion 111 or other parts of the refrigeration apparatus 100, which could otherwise be used for storage (e.g. of foodstuffs). A user of the refrigeration apparatus may "defrost" the refrigeration apparatus 100 periodically by allowing the freezer portion 111 to heat up to a point at which the ice melts, and then removing the resulting liquid water. Some known refrigeration apparatus have a mechanism, such as a heating resistor or other heating element, for heating up the freezer portion 111 briefly in order to melt the ice layer and thereby defrost the freezer portion 111. Such a "defrost process" may be performed automatically and periodically on a cycle, irrespective of how much frost has actually built up on the evaporator 122.
Figure 2 shows schematically a refrigeration apparatus 200 in accordance with examples described herein. The refrigeration apparatus 200 has a space 210 in which a freezer portion 211 is cooled by an evaporator 222 so as to be below 0°C, in the same manner as described above. The principles discussed herein may also be applied to a refrigeration apparatus 200 that does not have a freezer portion as such and the interior of which is (only) cooled to temperatures above freezing.
The refrigeration apparatus 200 comprises a heat scavenger 230. The heat scavenger 230 is constructed and arranged to capture heat from the condenser 224 that is normally transferred to the environment, and to transfer the captured heat to a part of the refrigeration apparatus 200 that is susceptible to freezing. This transfer of heat can defrost the part if it has frozen or if frost has built up on it. In this example, the part of the refrigeration apparatus 200 to which heat is transferred is the evaporator 222.
The heat scavenger 230 is an arrangement that is suitable to capture heat from one location or region and transfer it to another location or region. In this example, the heat scavenger 230 comprises a heat capture portion 231 for capturing heat from the condenser 224, a heat output portion 232 for outputting captured heat to a part of the refrigeration apparatus 202, and a heat transfer portion 233 for transferring heat from the heat capture portion 231 to the heat output portion 232.
The heat capture portion 231 is located near to the part of the refrigeration apparatus 202 from which heat is scavenged. Therefore, the heat capture portion 231 is located near to the condenser 224. In this example, the heat capture portion 231 comprises one or more pipes 239 provided adjacent the condenser 224.
The heat output portion 232 is located near to the part of the refrigeration apparatus 202 that is to be heated for defrosting purposes. Therefore, in this example, the heat output portion 232 is located near to the evaporator 222. In this example, the heat output portion 232 comprises an array of pipes 240 provided adjacent the evaporator 222.
The pipes of the heat capture portion 231 have walls formed from a material that is highly thermally conductive, such as for example a metal. This allows the walls to absorb heat from the hot condenser 224. The pipes of the heat output portion 232 also have walls formed from a material that is highly thermally conductive, such as for example a metal. This allows the walls to release heat transferred from the heat capture portion 231 to the cold part of the refrigeration apparatus 202 that is susceptible to frosting, which in this example is the evaporator 222. The pipes contain a heat transfer fluid 234 suitable for transferring heat to and from the pipe walls. In this example, the heat transfer fluid 234 is air. In another example, the heat transfer fluid 234 is water.
In an example, the one or more pipes 239 of the heat capture portion 231 have an open end so that the one or more pipes 239 can capture warm ambient air in the region of the condenser 224 and transfer it to the heat output portion 232 via the heat transfer portion 233. In this example, the heat capture portion 231 may include a funnel for capturing air heated by the condenser and directing it into the open end(s) of the one or more pipes 239. The funnel may be located above the condenser 224 to capture rising hot air heated by the condenser 224.
The heat transfer portion 233 is located between the heat capture portion 231 and the heat output portion 232. The heat transfer portion 233 connects the heat capture portion 231 to the heat output portion 232 such that they are in fluid communication with one another. This allows the heat transfer fluid 234 to flow between the heat capture portion 231 and the heat output portion 232. In this example, the heat transfer portion 233 comprises a pipe 241. The pipe 241 connects the one or more pipes 239 of the heat capture portion 231 and the one or more pipes 240 of the heat output portion 232 such that the one or more pipes 239 of the heat capture portion 231 are in fluid communication with the one or more pipes 240 of the heat output portion 232. This allows the heat transfer fluid 234, when heated, to flow from the heat capture portion 231 and to the heat output portion 232 under natural convection. The heated heat transfer fluid 234 can then release its heat to the part of the refrigeration apparatus 202 that is susceptible to freezing because the part is at a lower temperature than the heat transfer fluid 234. The cooled heat transfer fluid 234 can then flow back to the heat capture portion 231 under natural convection to be heated again by the condenser 224. The pipe 241 of the heat transfer portion 233 may be surrounded by a thermally insulating material in order to reduce heat loss from the heat transfer fluid 234 in the heat transfer portion 233.
In this example, the heat output portion 232 is located higher (i.e. at a greater elevation) than the heat capture portion 231 when the refrigeration apparatus 202 in normal use. This facilitates transfer of heat transfer fluid 234 heated by heat scavenged at the heat capture portion 231 t through the heat transfer portion 233 and to the heat output portion 232 using convection. In another example, a pump is provided to assist in moving heat transfer fluid 234 between the heat capture portion 231 and the heat output portion 232.
In another example, the heat capture portion 231, the heat output portion 232 and the heat transfer portion 233 each comprise one or more solid parts or cylinders formed from a material that is highly thermally conductive, such as for example a metal. In this example, there is no heat transfer fluid 234. Instead, heat conducts through the heat scavenger 230 to the part of the refrigeration apparatus 202 that is susceptible to frosting. Heat conducts from the hot condenser 224 to the one or more cylinders of the heat capture portion 231, through the one or more cylinders of the heat transfer portion 233, to the one or more cylinders of the cold heat output portion 232, and then to the part of the refrigeration apparatus 202 that is susceptible to frosting.
The heat scavenger 230 may include one or more valves 235. In this example, one valve 235 is provided. The one or more valves 235 act as "circuit breakers" and are constructed and arranged to allow for control of heat transfer by the heat scavenger 230, from the condenser 224 to the part of the refrigeration apparatus 202 that is susceptible to frosting. In this example, the one or more valves 235 control the heat transfer between the condenser 224 and the part of the refrigeration apparatus 202 that is susceptible to frosting by controlling the flow of the heat transfer fluid 234 between the heat capture portion 231 and the heat output portion 232. When the valve 235 is closed, the heat transfer fluid 234 cannot easily transfer from the heat capture portion 231 to the heat output portion 232. When the valve 235 is open, the heat transfer fluid 234 can easily transfer from the heat capture portion 231 the heat output portion 232.
In an example, the heat scavenger 230 may include a plurality of valves 235, each valve allowing for control of heat transfer by the heat scavenger 230, from the condenser 224 to a different region of the part of the refrigeration apparatus 202 that is susceptible to frosting. This provides for selective control of the defrosting of multiple regions of the part of the refrigeration apparatus 202 that is susceptible to frosting. This is useful if, for example, only one region of the part of the refrigeration apparatus 202 that is susceptible to frosting requires defrosting.
The heat scavenger 230 may include a sensor 236 for providing a measure of the temperature of the part of the refrigeration apparatus 202 that is susceptible to frosting, which in this example is the evaporator 222. The sensor is a temperature sensor. The sensor 236 in this example is a negative temperature coefficient resistor. In another example, the heat scavenger 230 may include multiple sensors for providing a measure of the temperature of multiple regions of the part or parts of the refrigeration apparatus 202 that is or are susceptible to freezing.
The heat scavenger 230 may also include a heater 237. In one example, the heater 237 is an electrical heating resistor. The heating resistor may include a relay for controlling activation of the heating resistor. The heater 237 may be is provided on or attached to the condenser 224. This allows the heater 237, when energised, to heat the condenser 224, increasing its temperature and thus increasing the temperature of the heat transfer fluid 234 in the heat capture portion 231 of the heat scavenger 230, which is adjacent the condenser 224. In another example, the heater 237 may be provided on or attached to the heat scavenger 230 so as to provide heat to the heat capture region 231 directly. If the compressor 223 is switched off, the heater 237 may provide heat (directly or indirectly) to the heat capture portion 231, which compensates for heat not being provided as a result of the compressor 223 interacting with refrigerant flowing between the condenser 224 and the evaporator 222. In another example, multiple heaters are provided for heating multiple regions of the condenser 224 or the heat scavenger 230.
In this example, a controller 238, which may be a processor or the like, is provided for controlling the operation of the heat scavenger 230. The controller 238 may be electrically connected to the valve 235, the sensor 236 and the heater 237. The controller 238 may also be electrically connected to the compressor 223 of the condenser 224.
The controller 238 is configured to activate the heat scavenger 230 as necessary to capture and transfer heat from the condenser 224 to a part of the refrigeration apparatus 202 that is susceptible to frosting. In one example, the controller 238 is configured to obtain a measure of the temperature of the part of the refrigeration apparatus 202 that is susceptible to frosting and compare the obtained temperature with a first predetermined threshold temperature. The controller 238 is configured to activate the heat scavenger 230 when the temperature of the part reaches or decreases below the first predetermined threshold temperature. The first predetermined threshold temperature may be a temperature that indicates that the part of the refrigeration apparatus 202 that is susceptible to frosting has frosted/frozen (or at least that the part has partially frosted). For example the first predetermined threshold temperature may be equal to or less than 0°C. As a specific example, the first predetermined threshold temperature may be -3°C.
In an example, the controller 238 is configured to obtain a measure of the temperature of the part of the refrigeration apparatus 202 that is susceptible to frosting, whilst the heat scavenger 230 is activated and compare the obtained temperature with a second predetermined threshold temperature. The controller 238 is configured to deactivate the heat scavenger 230 when the temperature of the part reaches or increases above the second predetermined threshold temperature. The second predetermined threshold temperature may be a temperature that indicates that the part of the refrigeration apparatus 202 that is susceptible to frosting has thawed or defrosted (or has at least partially defrosted). For example the second predetermined threshold temperature may be equal to or greater than 1°C. As a specific example, the second predetermined threshold temperature may be 3°C.
In an example in which the heat scavenger 230 includes multiple temperature sensors for a particular part or region that is susceptible to frosting, the controller 238 is configured to calculate and use an average of the temperatures obtained from the sensors.
In one example in which the heat scavenger 230 is additionally provided with a heater 237, the controller 238 is also configured to activate the heater 237 if it detects that the compressor 223 is switched off after activating the heat scavenger 230 because the temperature of the part has reached or decreased below a first predetermined threshold temperature. This allows the heater 237 to provide heat to the heat capture portion 231, which compensates for heat not being provided as a result of the compressor 223 interacting with refrigerant flowing between the condenser 224 and the evaporator 222.
An example of the controller 238 activating and deactivating the heat scavenger 230 will now be described.
Initially, the refrigeration apparatus 202 is working as normal, in which the compressor 223 is active and the freezer portion 211 of the space 210 is being cooled to below 0°C.
The controller 238 periodically obtains a measure of the temperature of the evaporator 222 from the temperature sensor 236, which in this example is the part of the refrigeration apparatus 202 that is susceptible to frosting. The controller 238 then compares this obtained temperature with the first predetermined threshold temperature. If the controller 238 obtains a temperature that is at or below the first predetermined threshold temperature, the controller 238 activates the heat scavenger 230 to capture heat from the condenser and transfer it to the evaporator 222. The controller 238 activates the heat scavenger 230 by opening the valve 235, which puts the heat capture portion 231 of the heat scavenger 230 in fluid communication with the heat output portion 232, via the heat transfer portion 233.
In an example, the first predetermined threshold temperature is -3°C and the controller 238 obtains a temperature of -2°C from the temperature sensor 236. The controller 238 therefore takes no action regarding the obtained temperature and does not activate the heat scavenger 230. The controller 238 continues to periodically obtain a measure of the temperature of the evaporator 222 from the temperature sensor 236.
In another example, the first predetermined threshold temperature is -3°C and the controller 238 obtains a temperature of -4°C from the temperature sensor 236. This temperature indicates that the temperature within the evaporator has reduced to a temperature that makes frosting of the evaporator likely. Such frosting decreases the performance of the evaporator 222. Since the obtained temperature is below the first predetermined threshold temperature, the controller 238 activates the heat scavenger 230 by opening the valve 235.
The condenser 224, which is transferring heat from the evaporator 222 to the environment via the circulating refrigerant, heats the heat transfer fluid 234 in the heat capture portion 231 of the heat scavenger 230 during use. When the valve 235 is closed, the hot heat transfer fluid 234 is contained within the heat capture portion 231. However, when the controller 238 activates the heat scavenger 230 it opens the valve 235, which allows the hot heat transfer fluid 234 to flow from the heat capture portion 231, through the heat transfer portion 233 and to the heat output portion 232 due to natural convection. The hot heat transfer fluid 234 is replaced by colder heat transfer fluid 234 from the heat output portion 232. Therefore, the controller 238 opening the valve 235 increases the temperature within the evaporator 222. The increased temperature helps to defrost the evaporator 222 by melting any ice formed within it.
Prior to opening the valve 235, the controller 238 checks whether or not the compressor 223 is active. If the compressor 223 is not active, the controller 238 activates the heater 237 to heat the heat transfer fluid 234 in the heat capture portion 231 of the heat scavenger 230. This provides heat that can be scavenged by the heat scavenger 230 even whilst refrigerant is not circulating around the refrigeration apparatus 202. The controller 238 deactivates the heater 237 if the compressor 223 is turned on.
The controller 238 continues to periodically obtain a measure of the temperature of the evaporator 222 from the temperature sensor 236. Whilst the heat scavenger 230 is activated, if the controller 238 obtains a temperature from the temperature sensor 236 that is the same as or greater than the second predetermined threshold temperature then it deactivates the heat scavenger 230.
In example, the second predetermined threshold temperature is 3°C and the controller 238 obtains a temperature of 2°C from the temperature sensor 236. Therefore, the controller 238 does not deactivate the heat scavenger 230 and it thus remains activated. The controller 238 continues to periodically obtain a measure of the temperature of the evaporator 222 from the temperature sensor 236.
In another example, the second predetermined threshold temperature is 3°C and the controller 238 obtains a temperature of 4°C from the temperature sensor 236. Therefore, the controller 238 deactivates the heat scavenger 230 by closing the valve 235 (and deactivating the heater 237 if it is active). The controller 238 continues to periodically obtain a measure of the temperature of the evaporator 222 from the temperature sensor 236.
An advantage of the heat scavenger 230 is that a part of a refrigeration apparatus 202 that is susceptible to frosting, such as the evaporator 222, can be defrosted using heat from the condenser 224 that would otherwise be transferred to the environment (i.e. wasted). It is therefore not necessary for the refrigeration apparatus 202 to generate heat to defrost the part. The heat scavenger 230 thus provides an energy efficient way of defrosting a part of the refrigeration apparatus 202 so as to maintain the part in good working order.
It will be understood that the processor or processing system or circuitry referred to herein may in practice be provided by a single chip or integrated circuit or plural chips or integrated circuits, optionally provided as a chipset, an application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), digital signal processor (DSP), graphics processing units (GPUs), etc. The chip or chips may comprise circuitry (as well as possibly firmware) for embodying at least one or more of a data processor or processors, a digital signal processor or processors, baseband circuitry and radio frequency circuitry, which are configurable so as to operate in accordance with the exemplary embodiments. In this regard, the exemplary embodiments may be implemented at least in part by computer software stored in (non-transitory) memory and executable by the processor, or by hardware, or by a combination of tangibly stored software and hardware (and tangibly stored firmware).
Although at least some aspects of the embodiments described herein with reference to the drawings comprise computer processes performed in processing systems or processors, the invention also extends to computer programs, particularly computer programs on or in a carrier, adapted for putting the invention into practice. The program may be in the form of non-transitory source code, object code, a code intermediate source and object code such as in partially compiled form, or in any other non-transitory form suitable for use in the implementation of processes according to the invention. The carrier may be any entity or device capable of carrying the program. For example, the carrier may comprise a storage medium, such as a solid-state drive (SSD) or other semiconductor-based RAM; a ROM, for example a CD ROM or a semiconductor ROM; a magnetic recording medium, for example a floppy disk or hard disk; optical memory devices in general; etc.
The examples described herein are to be understood as illustrative examples of embodiments of the invention. Further embodiments and examples are envisaged. Any feature described in relation to any one example or embodiment may be used alone or in combination with other features. In addition, any feature described in relation to any one example or embodiment may also be used in combination with one or more features of any other of the examples or embodiments, or any combination of any other of the examples or embodiments. Furthermore, equivalents and modifications not described herein may also be employed within the scope of the invention, which is defined in the claims.

Claims

A refrigeration apparatus comprising:
a condenser;

an evaporator in fluid communication with the condenser; and

a heat scavenger constructed and arranged to capture heat from the condenser and to transfer the heat to a part of the refrigeration apparatus that is susceptible to frosting for defrosting said part.
A refrigeration apparatus according to claim 1, wherein said part is the evaporator.
A refrigeration apparatus according to claim 1 or claim 2, comprising a controller, the controller being configured to activate the heat scavenger to capture and transfer heat from the condenser to a part of the refrigeration apparatus that is susceptible to frosting.
A refrigeration apparatus according to claim 3, comprising a temperature sensor for providing a measure of the temperature of a part of the refrigeration apparatus that is susceptible to frosting, wherein the controller is configured:
to obtain a measure of the temperature of the part of the refrigeration apparatus that is susceptible to frosting;

compare the obtained temperature with a first predetermined threshold temperature; and

activate the heat scavenger when the obtained temperature is or decreases below the first predetermined threshold temperature.
A refrigeration apparatus according to claim 4, wherein the controller is configured:
to obtain a measure of the temperature of the part of the refrigeration apparatus that is susceptible to frosting;

compare the obtained temperature with a second predetermined threshold temperature that is higher than the first predetermined threshold temperature; and

if the heat scavenger is activated, deactivate the heat scavenger when the temperature of the part is or increases above a second predetermined threshold temperature.
A refrigeration apparatus according to claim 4 or claim 5, comprising a plurality of temperature sensors, wherein the controller is configured to obtain an average of the temperatures sensed by the plurality of temperature sensors.
A refrigeration apparatus according to any of claims 3 to 6, comprising a heater constructed and arranged to heat the condenser, wherein the controller is configured to activate the heater if the controller determines that a compressor of the condenser is off whilst the heat scavenger is activated.
A refrigeration apparatus according to any of claims 1 to 7, wherein the heat scavenger comprises:
one or more pipes conveying a heat transfer fluid for transferring heat from the condenser to the part of the refrigeration apparatus that is susceptible to frosting; and

a valve constructed and arranged to open to allow flow of the heat transfer fluid and to close to prevent flow of the heat transfer fluid.
A method of defrosting a part of a refrigeration apparatus, the method comprising:
activating a heat scavenger to capture heat from a condenser of the refrigeration apparatus and to transfer the heat to a part of the refrigeration apparatus that is susceptible to frosting for defrosting said part.
A method according to claim 9, wherein said part is an evaporator of the refrigeration apparatus.
A method according to claim 9 or claim 10, wherein the heat scavenger is activated by a controller.
A method according to any of claims 9 to 11, comprising:
obtaining a measure of the temperature of the part of the refrigeration apparatus that is susceptible to frosting;

comparing the obtained temperature with a first predetermined threshold temperature; and

activating the heat scavenger when the obtained temperature is or decreases below the first predetermined threshold temperature.
A method according to any of claims 9 to 12, comprising:
obtaining a measure of the temperature of the part of the refrigeration apparatus that is susceptible to frosting;

comparing the obtained temperature with a second predetermined threshold temperature; and

if the heat scavenger is activated, deactivating the heat scavenger when the temperature of the part is or increases above a second predetermined threshold temperature.
A method according to any of claims 9 to 13, comprising activating a heater that to heat the condenser if a compressor of the condenser is off whilst the heat scavenger is activated.
A method according to any of claims 9 to 14, comprising:
activating the heat scavenger by opening a valve to allow a heat transfer fluid to flow to transfer heat from the condenser to the part of the refrigeration apparatus that is susceptible to frosting; and

deactivating the heat scavenger by closing the valve to stop the heat transfer fluid from flowing to prevent heat transfer from the condenser to the part of the refrigeration apparatus that is susceptible to frosting.