GB2570632A

GB2570632A - Cooled display cabinet

Info

Publication number: GB2570632A
Application number: GB1720304.3A
Authority: GB
Inventors: Andrew Perry Anthony
Original assignee: Counterline Holdings Ltd
Current assignee: Counterline Holdings Ltd
Priority date: 2017-12-06
Filing date: 2017-12-06
Publication date: 2019-08-07
Also published as: GB201720304D0

Abstract

A cooled cabinet 10 which has an enclosure 16 for display of produce. A cooling system and temperature control arrangement are provided for cooling the housing 16. The temperature control arrangement controls the cooling system in response to a sensed interior temperature. The chilled cabinet 10 is provided with an ambient humidity sensor, and the temperature control arrangement is configured to permit temperature in the enclosure to rise in response to excess sensed ambient humidity. A method of controlling temperature in the cooled cabinet 10 is also disclosed, as is a cooled display cabinet in which a control system including at least one temperature-responsive sensor regulates the temperature in the cabinet. Here, a digital processing system receives and stores sensor data, and outputs this data to a remote resource through an interface to a cellular telecommunications network.

Description

COOLED DISPLAY CABINET

The present invention relates to cooled product display cabinets. According to one aspect, the invention has implications for the mode of temperature control in such cabinets. According to another aspect, the invention provides improvements in monitoring and/or adjusting performance of such cabinets.

Chiller cabinets are very widely known and used, especially but not exclusively for display of product for retail sale. Some foods and beverages need to be maintained at reduced temperature (compared with ambient) to prolong their shelf life whilst on display in a shop or other retail premises. Others, such as drinks, are best supplied to the customer ready chilled. In order to keep product cool whilst displaying it to potential purchasers, users or consumers, known chiller cabinets typically have an enclosure formed at least in part by transparent panels, e.g. of glass. Many vending machines, such as those used for automatically vending drinks and snacks to customers and taking payment, likewise serve to keep the vended product cool and display it to the customer through a suitable window, and constitute cooled product display cabinets for present purposes.

A variety of refrigeration technologies may in principle be used in cooled display cabinets but a conventional type of heat pump based on circulation of refrigerant through a compressor and an evaporator in a vapour compression cycle is very often chosen. Possible alternatives include for example solid state heat pumps such as Peltier devices. Whatever form of cooling system is adopted, it is typically controlled to maintain a certain temperature in the cabinet enclosure. This may be done using closed loop control logic sensitive to interior cabinet temperature.

In certain instances involving food or drink, regulations require maintenance of temperature below a chosen value. Thus for example certain chilled foods must be maintained below eight degrees Centigrade. In such instances it is common to provide a safety margin, e.g. by setting the controller 22 to maintain a temperature below five degrees.

Problems can be encountered with cooled display cabinets due to adverse ambient conditions. One of these problems is condensation taking place on surfaces of the cabinet. This is unsightly. Water droplets or film collecting on transparent parts of the cabinet's enclosure may obscure a user's view of the product within, impairing the cabinet's function as a display and/or a sales tool. Moisture collecting in the cabinet can also be deleterious to the quality of the displayed product, and in extreme cases standing water can even collect inside the enclosure. Other problems encountered due to adverse ambient conditions include freezing of ambient water vapour on evaporator coils, and malfunctions and/or reductions in component lifetime or service interval of the cooling system due to excessive duty cycle.

According to a first aspect of the present invention there is a cabinet for display of product, the cabinet comprising an enclosure for display of product and a cooling system and associated temperature control arrangement for cooling the enclosure, the temperature control arrangement being configured to control the cooling system in response to a sensed interior temperature, wherein the cabinet is provided with an ambient humidity sensor and the temperature control arrangement is configured to permit the cabinet interior temperature to rise in response to excess ambient humidity. The cabinet is thus able to respond to ambient humidity in a manner which can alleviate the aforementioned problems.

A further aspect of the present invention is concerned with monitoring performance of, and/or controlling performance of cooled cabinets, including without limitation chiller cabinets, whether used for display of product or not, freezer cabinets, whether used for display of product or not, and other types of self-contained cooled cabinets.

Modern cooled cabinets are in some cases provided with a digital controller capable of monitoring, logging and reporting various aspects of the cabinet's performance. Such data can be put to a range of uses. For the user, it may for example be advantageous to be able to demonstrate that enclosure temperature has remained within the range required by regulations. For servicing purposes, data on aspects such as duty cycle has implications for service interval. The data may also be interrogated to establish whether the unit is performing efficiently and effectively. For example excessive average duty cycle may be indicative of a fault, unless perhaps explained by sustained high ambient temperatures. From the point of view of the equipment manufacturer or supplier, such data may also be useful in establishing whether the cabinet has been subject to abuse or to operation in adverse conditions. For example it may be a condition of a manufacturer's warranty that the cabinet should not be used in ambient temperatures exceeding a certain level.

Modern cabinets are able to detect and report various failure modes and malfunctions, e.g. through a system of error codes, and these need likewise to be logged and reported by some suitable means.

Digitally controlled cooled cabinets run software that regulates various functions of the cabinet, and which provides for adjustment of operating parameters such as target and max/min enclosure temperatures. Operating parameters set through the software may be controlled through a suitable form of digital interface, and software updates may need periodically to be distributed to cabinets running the software.

It is known to network certain types of cooled cabinets on a given site through a local area network in the form of a wired LAN or a local wireless network. This is useful for example on manufacturing or food processing sites having multiple cabinets, and for large scale retail outlets. But many cooled cabinets are installed in for example small retail premises having one or two such cabinets. Availability of a local area network with internet connection cannot be assumed, and nor can willingness of the retailer to connect the cabinet to any such network. From the point of view of a manufacturer of cooled cabinets, global export provides particular problems. The manufacturer may send cabinets around the world. Monitoring their performance, supplying software updates and other desirable functions

A known alternative is to provide instead for data to be logged at the cabinet and collected by an operative during a site visit. For this purpose the operative may for example use a portable digital processing device such as a tablet computer or smart phone. A data connection to the cabinet controller may for example be made through an RF data link, e.g. a link operating according to the Bluetooth® standard. This approach suffers from numerous practical shortcomings. Site visits constitute a considerable and often prohibitive expense. If data is received for processing only intermittently, during such visits, then for example diagnosis of fault conditions may be delayed. Dissemination of software updates can likewise be delayed or rendered impractical. Physical access to cabinets is not always available for service operatives, a particular issue for example at airports.

For all of these reasons there is a practical need for a technical solution to the problem of how to retrieve data from cooled display cabinets and/or how to provide for their adjustment and updating in a convenient and efficient manner.

According to a second aspect of the present invention there is a cabinet for display of product provided with a cooling system and with a digital controller configured to receive sensor data relating to performance of the cooling system, the digital controller being communicatively coupled to a wireless interface for exchange of data through a cellular network, the controller being configured to output a data set comprising or derived from the sensor data through the wireless interface through the cellular network.

Specific embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which:Figure 1 is a view from above and one side of a cooled cabinet operable according to the present invention;

Figure 2 is a side view of the same cooled cabinet, a side panel being omitted to reveal internal detail;

Figure 3 is a schematic diagram of selected parts of a control system of the cooled cabinet; and

Figure 4 is a scrap view of an upper part of the cabinet, parts of which are shown in phantom to show location of sensor parts of the control system.

The cooled cabinet 10 depicted in the drawings is suitable for use on retail premises or in other contexts where it is necessary to display produce and to maintain it at reduced temperature, as for example in display of chilled desserts in a restaurant. This example uses a fabricated stainless steel structure 12 mounting glass panels 14 to form a cabinet enclosure 16, but any number of different materials and techniques could be used for the physical construction of the cabinet, and the physical layout may differ greatly from one embodiment to another. For access to the interior of cabinet enclosure 16, it has a hinged door 18 in the present embodiment. However it is not vital to the invention that the cooled cabinet enclosure 16 be entirely closed in this manner - the invention could for example be implemented in relation to the type of cooled cabinet that has one or more constantly open faces. Shelves 20 are provided within the enclosure 16 for supporting and displaying product.

A cooling system and associated controller 22 (see Figures 2 and 3) are housed in an opaque base portion 23 of the cabinet. While the invention is not limited to implementation with any specific type of cooling system, this example uses a conventional refrigeration unit in which refrigerant is circulated by a compressor 24 through a condenser 26 and an expansion valve to an evaporator 28, and back to the compressor. A fan 30 circulates air over the cold evaporator 28 and the air, thus chilled, is itself circulated through ducting 32 to the cabinet enclosure 16, reducing its temperature.

Powers supplied to the compressor 24 and the fan 30 are controlled by the controller 22, which in this example is a programmable digital unit incorporating a microprocessor. The primary control variable is temperature. The practical requirement of course is to exercise control over temperature in the enclosure 16. Temperature in the enclosure may be directly sensed for this purpose using a sensor disposed in the enclosure 26, but in the present embodiment an alternative approach is adopted which uses a temperature probe disposed to sense temperature of air delivered from the evaporator 28. The assumption is made that temperature in the enclosure 16 will be higher than the resultant sensed temperature by an offset value. By way of example only, this offset value may be of the order of four degrees centigrade. So to achieve an enclosure temperature of say five degrees, the controller 22 bases temperature control on a target value of 5-4 = 1 degree Centigrade. Control is in the present example made in closed loop, negative feedback manner as is well known to the skilled person. In principle other control techniques could be used. PDI (proportional differential integral) control logic may be employed, although it is not necessary for implementation of the invention. The target temperature may be a single value or may be a range, so that the cooling system is activated when sensed temperature falls below the bottom limit of the range and inactivated when sensed temperature exceeds the upper end of the range.

In accordance with an aspect of the present invention, and as represented in Figure 3, the cabinet 10 is provided with a humidity sensor 36 responsive to ambient humidity - i.e. humidity local to the cabinet 10 and outside the enclosure 16. For this purpose the sensor 36 is mounted on the cabinet's exterior. Figure 4 shows the sensor 36 in situ on the cabinet 10. It is in this example mounted at an upper edge of the cabinet and is concealed within a trim piece 37, but exposed to ambient air through a grille 39 formed in the trim piece. In the present example the sensor 36 detects relative humidity. Ambient temperature is also detected through a temperature sensor 41. Suitable miniature sensors are widely commercially available. The output of the humidity sensor 36 is led to the controller 22 and is, in accordance with the present invention, used to modify temperature control in response to ambient humidity, in a manner which alleviates the problems described above resulting from adverse ambient conditions.

Specifically, the controller 22 implements a control strategy in which temperature in the enclosure 16 is permitted to rise somewhat in response to excess ambient humidity. This strategy will now be described.

Sensed local ambient humidity may be subject to short term variations due to a range of factors. As an example, if there is a coffee maker in the vicinity of the cabinet, the water vapour it releases may lead to sensor readings which are transient and essentially, for present purposes, aberrant. To reduce the effect of such transient conditions, the control strategy may for example use low pass smoothing applied to the output of the humidity sensor 36, or may - as in the present embodiment - apply a delay in responding to it. Thus in the present instance an excess value of the sensed humidity is ignored by the controller 22 unless it is sustained for a predetermined period, which is of the order of a few minutes.

If the output of the humidity sensor 36, subject to such smoothing or delay, rises above a certain threshold value then the controller 22 responds by adjusting the enclosure temperature, permitting it to rise.

It was mentioned above that under normal operating conditions a margin is maintained between the actual enclosure temperature and the maximum tolerable enclosure temperature. Hence when ambient conditions demand it, the actual temperature can be permitted to increase somewhat without compromising safety. Where perishable items such as certain food or drink are concerned, the strategy may limit the temperature adjustment that can take place to avoid the items being exposed to temperature outside an acceptable range.

The adjustment takes the form of an increase in the target temperature for the aforementioned closed loop control logic. In fact in the aforementioned example where an offset is applied to the sensed temperature, the adjustment is made at a software level by changing the offset, which is reduced in response to excess ambient humidity.

In the simplest example, the strategy may involve only making a predetermined change to the target temperature when relative humidity rises above a predetermined level. A more sophisticated strategy, implemented in the present embodiment, applies multiple discrete levels of adjustment to the target temperature in response to corresponding discrete threshold values of relative humidity. Thus:

if the smoothed or delayed value of relative humidity exceeds a first level Hi then target temperature is increased by a first value Ti_; if the smoothed or delayed value of relative humidity exceeds a second level H₂then target temperature is increased by a second value T₂and_; if the smoothed or delayed value of relative humidity exceeds a third level Hathen target temperature is increased by a third value T3 whereTi<T₂<T3 and Hi>H₂>H3. The number of discrete adjustments need not be precisely three. Other logic or calculations may be applied to achieve the desired effect, which is that enclosure temperature is allowed to rise in some progressive manner with rising relative humidity. Thus for example it would be possible to subject the output of the humidity sensor to low pass smoothing, subtract a chosen value (the threshold value of relative humidity) from it, and in the event that the result of the subtraction is positive, multiply that by a chosen factor to obtain the required change in the target temperature., the effect being that the temperature adjustment is proportional to the excess ambient humidity above the threshold value. Other, non-linear, functions could be used to obtain the required temperature adjustment form the ambient conditions.

It was explained above that one of the major deleterious factors arising from adverse ambient conditions is condensation. The propensity for condensation to occur increases with increasing relative humidity. But condensation on a given surface is reduced by raising the temperature of that surface. By allowing the enclosure temperature to rise in response to excess humidity, it is found that the deleterious effects of condensation in and on the cooled cabinet can be greatly alleviated. Other problems such as freezing of water vapour from the air on the evaporator coils are likewise alleviated.

In accordance with an aspect of the present invention, the controller 22 is communicatively coupled through cabling 40 to a network interface 42 in the form of a modem for connection to a cellular network. The network in question is a mobile telephony network. It is a wide area network. In the present embodiment the network is a GSM (Global System for Mobile communication) network, although it could be that the GSM system will be superceded by a different cellular network within the lifetime of the present patent, and the invention may be implemented with any such future cellular network technology. Still more specifically, the illustrated embodiment uses a modem operating according to the 4G broadband cellular network standard, although this is expected to be superceded within the lifetime of the patent and whatever suitable cellular standards are adopted in the future may be used in future embodiments of the invention.

By use of the cellular network interface 42, the cabinet 10 is enabled to transmit data to, and receive data from, a server or other processing device which is off site, and potentially geographically remote from the cabinet 10. A manufacturer or service agent based in one country may sell cabinets to, or have responsibility for maintenance of, cabinets in a wide range of other countries. As an example, the present applicant manufactures cooled cabinets for export across the globe, including to numerous small customers and a very large group of countries. By virtue of connection to the cellular network, those cabinets will nonetheless be enabled to report performance data to their manufacturer or service agent and to receive adjustments, control inputs and software updates from it.

The practical implications are far reaching.

Data that can be measured or otherwise obtained at the cabinet 10 and output to a remote server can for example include:

- temperature in the cabinet's enclosure, which may for example be sensed and logged at predetermined time intervals;

- ambient temperature, which may for example be sensed and logged at predetermined time intervals;

- ambient humidity, which may for example be sensed and logged at predetermined time intervals;

- compressor and evaporator fan duty cycles. For example the time of activation/deactivation of these subsystems may be logged, and statistical data such as cumulative operational time for the subsystems can thus be derived;

- opening and closing of the enclosure, e.g. where access is provided through a door;

- indicators of malfunction, such as error codes;

- sales data, in the case of vending machines; and

- power consumption.

This list is non-limiting. Other operating parameters may be utilised.

A global population of cooled cabinets 10 is able, according to the present invention, to report this and potentially other data to a remote resource, such as a server maintained by the manufacturer. The received data from the population can be analysed in order for example to:

detect fault conditions for individual cabinets 10, and respond to them e.g. by offering remedial advice or the services of an engineer to the owner of the cabinet. To this end, a database of cooled cabinets 10 and associated owner/user identities and contact details may be maintained;

determine when adjustments are required to operating parameters of individual cooled cabinets 10 to enhance performance or avoid malfunction. The required adjustments can in many cases be made by adjustment of parameters in software through the network interface 42;

detect where cooled cabinets 10 are subject to inappropriate or abusive treatment. Providing such indicators to a central remote resource such as a server maintained by the manufacturer can for example enable the manufacturer to establish where conditions of a warranty have been breached. For example, the illustrated cooled cabinet 10 detects both ambient temperature and ambient humidity. Atypical warranty may be voided if the cabinet 10 is used in excessively warm or humid environments. Such conditions can be detected by the cooled cabinet 10 and reported to the remote resource;

obtain statistical performance data from the population of cooled cabinets 10 as a basis for improvements to future models and/or to software of the existing population of cooled cabinets 10;

provide operational data relating to their cabinet(s) 10. This may be real time or near real time operational data, e.g. to enable the customer to assure themselves that the cooled cabinet 10 is operational whenever required. Additionally or alternatively the operational data may comprise information derived from the reported data, such as average energy consumption over a period, or frequency of opening and closing of the cabinet door 16, which is relevant e.g. to sales activity.

The facility to send data and instructions to individual cooled cabinets 10, to groups of cooled cabinets 10, or to an entire population of cooled cabinets 10 through their network interfaces 42 is also highly advantageous. For example, revisions to settings, to firmware or to other aspects of the software of the cooled cabinet 10 can be transmitted directly to it. As already pointed out, adjustments to operating parameters can be made without need of a site visit.

A data logging and transfer strategy is implemented in the present embodiment to moderate the consumption of network bandwidth and/or connection time by the network interface 42. It is typically not necessary for data to be continuously reported through the cellular network. Instead the controller 22 may log data over a certain period and transmit it at intervals-once per day, for example - to the remote resource. Some pre-processing, compression or compaction of the data may be carried out at the controller 22 to reduce the volume of data transmitted. Transmission of data may be initiated by the controller 22 or it may be made in response to an interrogating signal from the remote resource. Real time data may nonetheless be obtained by interrogation of the controller 22 through the network interface 42.

The provision of the network interface 42 is especially advantageous where, as in the present embodiment, the cabinet 10 is additionally provided with a positioning system for determining the cabinet's geographical location. This makes it possible for a manufacturer or service agent to ascertain the geographical locations of the population of cabinets 10. This makes asset tracking of the population not only possible but very straightforward, with numerous resultant advantages. For example, security against theft can be improved, since an individual cabinet 10 can be tracked. Where necessary it can be shut down through the network interface 42 to prevent its use following theft. The manufacturer or service agent is able to obtain valuable data on the geographical spread of its customers.

The positioning system may be a satellite based positioning system, and may, in particular and without limitation, use GPS (Global Positioning System), Galileo (planned European positioning system), Beidou (planned Chinese positioning system), the Indian Regional Navigation Satellite system, or any successor system or technology. Non-satellite based positioning systems may be used.

The embodiments described above are presented by way of example and not of limitation. Numerous variations, modifications, improvements and changes are possible without departure from the scope of the claimed invention. For example, whereas the controller 22 of the illustrated embodiments is formed as a single unit, its functions may in other embodiments be divided among multiple units or 5 processors.

Claims

1. A cooled cabinet comprising an enclosure for display of product and a cooling system and temperature control arrangement for cooling the enclosure, the temperature control arrangement being configured to control the cooling system in response to a sensed interior temperature, wherein the cabinet is provided with an ambient humidity sensor and the temperature control arrangement is configured to permit temperature in the enclosure to rise in response to excess sensed ambient humidity.

2. A cooled cabinet as claimed in claim 1 in which the temperature control arrangement comprises a controller communicatively coupled to the ambient humidity sensor and to a temperature sensor arranged to sense the internal temperature, the controller being configured to apply closed loop control to the cooling system based on the sensed internal temperature to regulate the internal temperature toward a target temperature, and to raise the target temperature used in said closed loop control in response to excess sensed ambient humidity.

3. A cooled cabinet as claimed in claim 2 in which the closed loop control is based on a target range of temperature containing the target temperature.

4. A cooled cabinet as claimed in claim 2 or claim 3 in which output of the humidity sensor is smoothed, subject to a delay or otherwise processed to reduce the effect of transient variations in sensed humidity on the adjustment of target temperature.

5. A cooled cabinet as claimed in any of claims 2 to 4 in which the temperature sensor is arranged to sense temperature of air flow directed to the enclosure from the cooling system.

6. A cooled cabinet as claimed in any of claims 2 to 4 in which the temperature sensor is arranged to sense temperature in the enclosure.

7. A cooled cabinet as claimed in any preceding claim in which the permitted rise of temperature in the enclosure is limited to a predetermined value.

8. A cooled cabinet as claimed in any preceding claim in which the ambient humidity sensor is sensitive to relative humidity.

9. A cooled cabinet as claimed in any preceding claim in which the permitted rise in the temperature in the enclosure increases, in discrete steps or continuously, and over a selected range of sensed ambient humidity, with increasing sensed ambient humidity.

10. A cooled cabinet as claimed in any preceding claim which is provided with a network interface for exchanging data through a cellular telecommunications network and with a data processing device configured to log aspects of the cabinet's performance and to report them through the network interface.

11. A cooled cabinet as claimed in claim 10 further comprising a positioning system configured to determine the geographical location of the cooled cabinet, the data processing device being configured to report the determined geographical location to a remote resource through the network interface and the cellular telecommunications network.

12. A method of controlling temperature in a cooled cabinet having an enclosure for display of product, the method comprising sensing an interior temperature and controlling a cooling system of the cabinet to adjust temperature in the enclosure toward a target value or range, wherein the method further comprises sensing ambient humidity and raising the target value or range of temperature in the event that ambient humidity rises above a predetermined value.

13. A method as claimed in claim 12 in which the sensed ambient humidity is relative ambient humidity.

14. A method as claimed in claim 12 or claim 13 in which the sensed ambient humidity is smoothed, subject to a delay or otherwise processed in a manner which reduces the effect of transient variations of ambient humidity on temperature control.

15. A method as claimed in any of claims 12 to 14 in which target value or range of temperature is increased, in discrete steps or continuously, and over a selected range of sensed ambient humidity, with increasing sensed ambient humidity.

16. A cooled product display cabinet having an enclosure for receiving and displaying product, a cooling system for cooling the enclosure, a control system comprising a plurality of sensors including at least one sensor responsive to an internal temperature of the cabinet, the control system being configured to regulate temperature in the cabinet enclosure based on sensor output(s), a digital processing system configured to receive and at least transitorily store data relating to sensor output(s) and to operation of the control system, and an interface to a cellular telecommunications network, the digital processing system being configured to output said data through the interface to a geographically remote resource.

17. A cooled product display cabinet in which the digital processing system is configured to output any combination of the following through the interface to the cellular telecommunications network:

power consumption data;

data comprising or derived from activation and deactivation of parts of the cooling system;

data relating to malfunction of the cabinet, which may comprise error codes or may take another form;

sensed ambient temperature local to the cabinet;

sensed ambient humidity local to the cabinet;

opening and/or closing of a door or other closure associated with the enclosure.

18. A cooled product display cabinet as claimed in claim 16 in which the digital processing system is further configured to receive control inputs through the interface to the telecommunications network enabling the operation of the cooling system to be adjusted from the geographically remote resource.

19. A cooled product display cabinet as claimed in claim 18 in which the digital processing system is further configured to receive updates, amendments or additions to its software and/or firmware through the interface to the cellular communications network.

20. A cooled product display cabinet as claimed in any of claims 16 to 19 further comprising a positioning system for determining the geographical location of the cabinet, the digital processing system being configured to output the cabinet's location through the interface and the cellular telecommunications network to the remote resource.

21. A method of controlling a population of cooled product display cabinets as claimed in any of claims 16 to 20, comprising operating at least one server configured to receive and analyse data from the population of cabinets.