GB2442241A

GB2442241A - Improved refrigeration apparatus for supermarkets

Info

Publication number: GB2442241A
Application number: GB0619335A
Authority: GB
Inventors: Sew Hing Woo
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-09-29
Filing date: 2006-09-29
Publication date: 2008-04-02
Anticipated expiration: 2026-09-29
Also published as: GB0619335D0; GB2442241B

Abstract

A refrigerated display unit 9 may in use be supplied with cold air, rather than include a self-contained evaporator, and as such is termed a "coil-free" refrigerated display unit. Such a unit is suitable for use in a supermarket, and has a cold air inlet 25 for receiving a supply of cold air 26, a plenum chamber 19 in communication with the cold air inlet, and one or more air discharge outlets in communication with the plenum chamber that in use are arranged to deliver cold air into a stock display region, such as shelves 24. The unit also includes at least one air return inlet arranged to receive air from the stock display region, a second chamber 29 in communication with the at least one return inlet, and an air return outlet 27 in communication with the second chamber. The airflow through the unit may be regulated by one or more fans 18, which may be motorised and acoustically treated to attenuate transmission of noise. The fan or fans may be responsive to temperature sensors within the display unit, and where multiple fans are used these may be electronically coupled for synchronised operation. Alternatively, the invention relates to an air cooling plant suitable for a supermarket refrigeration system, which has an outlet and an inlet 16 for supplying/receiving air to/from a shop floor display unit, and an inlet 17 for receiving ambient air, which may be received from the exterior of the supermarket.

Description

IMPROVED REFRIGERATION APPARATUS FOR SUPERMARKETS

This invention relates to refrigeration apparatus for supermarkets, the refrigeration apparatus being of the type which delivers a flow of cold air over the products to be refrigerated.

BACKGROUND TO THE INVENTION

High street supermarkets sell food and non-food products. The non-food products include clothing, shoes, perfumery, toiletries, etc. The food products are either perishables or non-perishables. Examples of non-perishables are canned or bottled drinks, canned food, cereals, chocolates and cnsps. Examples of perishables are fresh meat, fresh fish, daivy products such as cheese and milk, and cooked ham. Perishables deteriorate in quality and shelf life when left at an ambient temperature. Keeping the perishables under refrigeration help to maintain the product quality for longer, and thereby improves the shelf life. In supermarkets, perishables are generally refrigerated in a refrigerated display unit which delivers a flow of cold air over the perishables.

The desire to improve the shelf life of perishables Is one of the many reasons why supermarkets are investing a large amount of money in chilling or freezing perishables.

There is a desire for refrigeration systems which not only extend the shelf life of the perishables, but which also cost less to install, operate and maintain.

The terms refrigerating', urefrige* refrigerated, refrigeration, coId and such like, as used herein, should be interpreted broadly, to encompass not only chilling to low temperatures (e.g. cold temperatures above O'C), but also to temperatures below 0C, i.e. freezing.

An example of a commonly-used conventional supermarket refrigeration system and shop floor display unit is shown in Figure 1. High pressure liquid refrigerant flows through insulated copper pipes 3a, from a compressor plant I to an evaporator coil 2 located inside a display unit 4 on the shop floor of the supermarket Refrigerant may also be sent to an evaporator coil 2 located inside an insulated storage room 5 (e.g. in the supermarket's warehouse or stockroom). The cold air is generated locally within the display unit from a combination of: (a) the thermodynamic change of the refrigerant as it evaporates from high pressure liquid to low pressure vapour inside the evaporator coil; and (b) the air loosing its heat as it passes through the evaporator coil fins. The low pressure vapour refrigerant in the evaporator coils 2 flows back to the compressor plant 1 through other Insulated copper pIpes 3b, where it is compressed to high pressure vapour, which then condenses to form high pressure liquid refrigerant. This high pressure liquid refrigerant is ready for use again. This cycle is repeated. An appropriate number of fans may be fitted on the evaporator coil 2 to assist in the circulation 6 of the cold air over the perishable products to be refrigerated.

The use of an evaporator coil 2 in the shop floor display unit 4 gives rise to several disadvantages. Since the external surface of the coil 2 is generally below O'C, it is susceptible to frosting and becoming iced up thereby affecting the efficiency of the coil 2.

Consequently, periodic defrosting is required. It will be appreciated that defrosting a display unit is time consuming, and the display unit does not refrigerate during the defrosting process, and so the display unit effectively rises in temperature, which then affects the products on display and is also costly.

Additionally, dunng service, the area in the vicinity of the evaporator coil is prone to collect dirt and debris (e.g. spilt peas and other food items), and consequently needs to be cleaned, particularly in order to provide a hygienic environment for food storage and sales.

With a view to overcoming these problems, a coil-free supermarket refngeration system has been proposed, as described in EP 0689 017 Al. This prior art discloses a refrigeration plant that generates cold air remote from the shop floor display unit. The cold air is sent along pipes from the refrigeration plant to the display unit, where it is then intended to circulate over the goods to be refrigerated. The circulated air is then collected and returned to the remote refngeration plant, to be cooled and re-used.

Some problems and shortcomings have been identified with the coil-free display units and refrigeration system disclosed in EP 0 689 017 Al. With a coil-free display unit, it will be appreciated that the airflow path through the display unit is of particular importance in order to ensure the even distilbution of the inlet cold air in the display unit and the efficiency of the unit, and It is considered that the airflow paths through the display units of EP 0 689 017 Al are hampered by the geometry and configuration of the units descnbed. Additionally, in the display units of EP 0689017 Al (Figure 2), incoming cold air is able to mix with warmer used air that has already passed through the stock display region. This increases the temperature of the incoming cold air, and consequently is considered to reduce the efficiency of the display unit.

Further, it is desirable to be able to add, remove or reposition refrigerated display units in a supermarket, for example to allow for seasonal variation in perishable stock, or to increase or decrease the refrigerated capacity of the store for future work. Such issues are not addressed in EP 0689017 Al.

There is also a desire to reduce the amount of energy used by the refrigeration plant when generating the cold air.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is provided a coil-free refrigerated display unit for use in a supermarket, the unit comprising: a cold air inlet, for receiving a supply of cold air a plenum chamber in communication with the cold air inlet; one or more air discharge outlets in communication with the plenum chamber, arranged to deliver cold air into a stock display region in use; one or more air return inlets, arranged to receive air from the stock display region in use; a second chamber in communication with the said one or more air return inlets; and an air return outlet In communication with the second chamber.

The provision of a plenum chamber and a separate second chamber advantageously keeps the incoming cold air (in the plenum chamber) separate from the warmer used air (in the second chamber) that has already passed through the stock display region. Thus, the incoming cold air and the warmer used air are not mixed within the plenum chamber, and consequently the temperature of the incoming cold air Is not increased as a result of mixing with the warmer used air. Thus, the efficiency of the display unit is improved. This is in contrast to the display units described in EP 0689017 Al, in which the incoming cold air is mixed with the warmer used air prior to delivery into the stock display region.

Additionally, by virtue of the plenum chamber and the separate second chamber of the present invention, the incoming cold air is not mixed with the warmer used air within the plenum chamber, and hence a less turbulent and more efficient airflow path is produced through the display unit.

The plenum chamber and the second chamber also advantageously enable a plurality of display units to be interconnected in a modular manner, end-to-end, and/or back-to-back, such that the plenum chambers of adjacent units are sealed in communication together, and the second chambers of adjacent units are sealed in communication together. This enables a number of dmplay units to be served by a fewer number of cold air inlets and air return outlets. This in turn leads to a simpler, quicker, and less expensive installation, that can also be readily adapted when more or fewer refrigerated display units are required, for example to cater for seasonal variation in perishable stock, or future work in the store.

Preferably the display unit further comprises a discharge chamber in communication with the plenum chamber, said discharge chamber incorporating at least one of the said one or more air discharge outlets.

Preferably the discharge chamber is above the stock display region. This benefits from the principle that a cold air stream naturally descends.

Preferably the discharge chamber incorporates means for enhancing airflow through the discharge chamber. The means for enhancing airflow through the discharge chamber may advantageously comprise one or more fans.

Preferably the display unit further comprises a back panel behind the stock display region, said back panel incorporating at least one of the said one or more air discharge outlets.

Also, or alternatively, the back panel may incorporate at least one of the said one or more air return inlets.

Advantageously, the back panel may form a wall of the plenum chamber, and/or a wall of the second chamber. This helps to minimise the amount of material used in the construction of the display unit, and hence helps to reduce the weight and cost of the unit.

Preferably the display unit further comprises a return chamber in communication with the second chamber, the return chamber incorporating at least one of the said one or more air return inlets.

Preferably the return chamber Is below the stock dIsplay region. This also benefits from the principle that a cold air stream naturally descends.

Preferably the return chamber incorporates means for enhancing airflow through the return chamber. The means for enhancing airflow through the return chamber may advantageously comprise one or more fans.

Particularly preferably the plenum chamber is above the second chamber. In a preferred embodiment, the plenum chamber is immediately above the second chamber, the plenum chamber and the second chamber being separated by a separating solid plate.

Preferably the display unit further comprises means for enhancing airflow through the cold air inlet, and/or means for enhancing airflow through the air return outlet. Particularly preferably said means for enhancing airflow comprise one or more motonsed fans. The motorised fans may be acoustically treated, and may be electronically coupled so as to enable them to operate in synchronism with each other.

Preferably the means for enhancing airflow are responsive to one or more temperature sensors disposed within the display unit, and in particular within the stock display region.

Thus, advantageously, the flow of cold air may be increased if the temperature in the stock display region is too high, or may be decreased lithe temperature in the stock display region is too low.

Particularly preferably the cold air inlet is aranged such that airflow entering the plenum chamber is not substantially impeded by any of the walls of the plenum chamber. For example, the cold air inlet may communicate vertically with the plenum chamber. This advantageously improves the efficiency of airflow through the plenum chamber, reducing turbulence and reducing the likelihood of any dead air within the plenum chamber.

Particularly preferably the plenum chamber is adapted to be directly coupled to, and in communication with, the plenum chamber of another such display unit. Similarly, the second chamber Is also preferably adapted to be directly coupled to, and in communication with, the second chamber of another such display unit. As mentioned above, this advantageously enables a plurality of display units to be interconnected in a modular manner.

In a similar manner, the discharge and return chambers may be adapted to be directly coupled to, and in communication with, the corresponding chambers of adjacent display units.

According to a second aspect of the present invention there is provided a supermarket refngeration system comprising: a display unit according to the first aspect of the invention; and an air cooling plant remote from the display unit; the air cooling plant being arranged to supply cold air to the cold air inlet of the display unit via a pipe or duct.

Preferably the air cooling plant is further arranged to receive air from the air return outlet of the display unit.

Particularly preferably the air cooling plant comprises an inlet for receiving ambient air and introducing such ambient air into the refrigeration system during use.

Preferably the refrigeration system further comprises a storage room also supplied with cold air from the air cooling plant.

Preferably the air cooling plant comprises one or more of the following: a compressor, a condenser, a liquid receiver.

Preferably the air cooling plant further comprises one or more of the following: evaporator coils, fans, motorised louvers.

In one embodiment, the said evaporator coils, fans or motorised louvers may be located in a first housing, and the said compressor, condenser or liquid receiver may be located in a second housing, the second housing being separate from the first housing.

Preferably the first housing and the second housing are thermally insulated.

Preferably the first housing and the second housing are provided with noise insulation material.

In an alternative embodiment, the said evaporator coils, fans or motorised louvers may be located in a common housing with the said compressor, condenser or liquid receiver.

Preferably the said common housing is thermally insulated.

Preferably the said common housing is provided with noise insulation matenal.

Preferably the refrigeration system further comprises thermal insulation around the pipes or ducts.

Preferably the refrigeration system further comprises noise insulation material around the pipes or ducts.

Preferably the refrigeration system further comprises an air filter in at least one pipe or duct.

Preferably the refrigeration system further comprises noise reduction means in at least one pipe or duct.

According to a second aspect of the present invention there is provided an air cooling plant for a supermarket refrigeration system, having an outlet for supplying cold air to a shop floor display unit, an Inlet for receMng air from a shop floor display unit, and an inlet for receiving ambient air.

The provision of an inlet for receiving ambient air advantageously enables cold ambient air, for example from outside the supermarket, to be drawn into the refrigeration system for use.

This can be particularly useful in cold countries or during winter months. If the outside ambient air is sufficiently cold, then it can be passed directly into the refrigeration system via the ambient air inlet, thereby saving energy that would otherwise need to be expended operating the compressor plant.

Preferably the inlet for receiving ambient air is in communication with the exterior of the supermarket.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of example only, and with reference to the drawings in which: Figure 1 illustrates an example of a commonly-used conventional supermarket refrigeration system, Including a shop floor display unit which Incorporates an evaporator coil; I0 Figure 2 illustrates an example of a supermarket refrigeration system utilising the present invention, including a first embodiment of a coil-free shop floor display unit suitable for (but not limited to) displaying chilled products above 0 C; Figure 3 illustrates in more detail the shop floor display unit shown in Figure 2; Figure 4 illustrates a discharge chamber suitable for use with the display unit of Figures 2 and 3; Figure 5a illustrates one possible configuration of a return chamber suitable for use with the display unit of Figures 2 and 3; Figure 5b iMustrates an alternative possible configuration of a return chamber suitable for use with the display unit of Figures 2 and 3; Figure 6 illustrates a second embodiment of a shop floor display unit according to the present invention, suitable for (but not limited to) displaying frozen products below 0 C; Figure 7 Illustrates a third embodiment of a shop floor display unit according to the present invention, also suitable for (but not limited to) displaying frozen products below 0 C; and Figure 8 illustrates a shop floor display unit comprising a combination of the display units of Figures 6 and 7.

In the figures, like elements are indicated by like reference numerals throughout.

In the figures, the arrows indicate the direction of fluid flow, e.g. along pipes and ducts. In Figures 2 to 8, the white open arrows indicate the direction of airflow through the parts of the refrigeration apparatus.

DETAILED DESCRIPTION OF PREFERRED EMBODiMENTS

The present embodiments represent the best ways known to the applicant of putting the invention into practice. However they are not the only ways in which this can be achieved.

By way of background, Figure 1 illustrates a commonly-used conventional refrigeration system used In supermarkets. High pressure liquid refrigerant flows through insulated copper pipes 3a, from a compressor plant I to an evaporator coil 2 located Inside a display unit 4 on the shop floor of the supermarket. Refrigerant may also be sent to an evaporator coil 2 located inside an insulated storage room 5 (e.g. in the supermarkets warehouse or stockroom). The cold air is generated locafly within the display unit from a combination of: (a) the thermodynamic change of the refrigerant from as It evaporates from high pressure liquid to low pressure vapour inside the evaporator coil; and (b) the air loosing its heat as it passes through the evaporator coil runs. The low pressure vapour refrigerant in the evaporator coils 2 flows back to the plant I through other insulated copper pipes 3b, where it is compressed to hugh pressure vapour, which then condenses to form high pressure liquid refrigerant. This high pressure liquid refrigerant Is ready for use again. This cycle is repeated. An appropriate number of fans may be fitted on the evaporator coil 2 to assist in the circulation 8 of the cold air over the products to be refrigerated.

Figure 2 illustrates an example of a supermarket refrigeration system utilising the present invention. High pressure liquid refrigerant flows along insulated copper pipes 3a from the compressor plant I to one or more evaporator coils 7 which are preferably housed in a remote insulated room 8. Inside the evaporator coils 7, the high pressure liquid refrigerant undergoes a thermodynamic change to low pressure vapour. The low pressure vapour leaves the evaporator coils 7 to return to the compressor plant 1 along other insulated copper pipes 3b. In the compressor plant I * the low pressure vapour is compressed to high pressure vapour which then condenses to high pressure liquid, which is ready for use again.

The refrigeration cycle repeats.

Thus, the cold air created by the thermodynamic change of the refrigerant inside the evaporator cods? from high pressure liquid to low pressure vapour preferably takes place in the remote insulated room 8. The cold air generated in this remote insulated room 8 is delivered to one or more modular shop floor display units 9 (which are described in detail below) and one or more storage rooms 10. preferably by insulated pipes or ducts 11. SImilar insulated pipes or ducts II are used to return the cold air to the remote room 8.

The cold air generated in the remote insulated room 8 is directly from a combination of: (a) the thermodynamic change of the refrigerant from high pressure liquid to low pressure vapour inside the evaporator coils 7, and (b) the air loosing its heat as It passes through the evaporator coil fins. The air leaving the evaporator coils 7 is the discharge air 12. This discharge air 12 may be passed through one or more of the following optional devices: I) one or more fans 13; ii) one or more noise absorbing materials 14; and/or iii) one or more filters and/or driers 15.

The discharge air 12 is delivered to the display units 9 located on the supermarket's sales floor and to the storage rooms 10 normally located in the supermarket's warehouse or stock room, preferably by insulated pipes or ducts 11.

After passing over the penshables to be refrigerated, the cold air delivered to the display units 9 and the storage rooms 10 is returned to the remote room 8 as return air 16, to be used again.

The compressor plant I is of normal standard refrigeration industry supply and the main components therein may include (but need not be limited to) compressors, condensers, liquid receiver, electrical control panels, electronic and mechanical controllers, mechanical and electrical switches and valves.

The remote room 8 houses the evaporator coils 7, fans 13 and motonsed louvers, and Is preferably insulated to minimise temperature loss and outbreak of equipment noise. The remote room 8 is shown in Figure 2 as being separate from the compressor plant 1.

However, there is no reason why the remote room 8 cannot be in the same housing as the compressor plant 1.

The size and number of the evaporator coils 7 and the size of the remote insulated room 8 is determined by, but not limited to, the temperature of the discharge air 12, outside ambient conditions, number of air changes, the temperature of the return air 16 into the evaporator coils 7, and the mass flow rate of air to the shop floor display units 9 and the warehouse storage rooms 10.

The remote insulated room 8 may be provided with an ambient air inlet (for inlet air 17), which advantageously enables cold ambient air, for example from the exterior of the supermarket, to be drawn into the refrigeration system for use. This is envisaged as being particularly useful in cold countries (e.g. Canada) or during winter months. If the outside ambient air is sufficiently cold, then it can be passed directly into the refrigeration system via the ambient air inlet, thereby saving energy that would otherwise need to be expended operating the compressor plant 1. If necessary, the outside ambient air may be cooled as required within the room 8, before being used in the refrigeration system. It will be appreciated that if the outside ambient air is colder than the temperature of the return air 16, then less energy will be required to cool the ambient air ready for use, than to cool the return air.

The arrangement of evaporator coils 7 can be of different types such as muW-pass, multiple coils or multi layered, but all performing similarly -that is, to generate the required mass flow rate of air at the specified conditions.

The fans 13 in the remote insulated room 8 are adequately sized and are used to circulate the discharge air 12. The number, size and type of fans will be selected depending on the mass flow rate, pressure drop, and conditions of the discharge air 12 such as temperature and humidity.

There may be separate chambers in the remote insulated room 8. Such chambers are to house the different pieces of equipment and to separate the discharge air 12 from the return air 16 and the inlet air 17. It is preferable for the return air 16 from the shop floor display units 9 and the storage rooms 10 to return to a mixing chamber in the remote insulated room 8. Whenever there is a requirement, inlet air 17 will flow into the mixing chamber to ensure adequate mass flow rate is supplied to the evaporator coils 7, which in turn supplies the shop floor display units 9 and the warehouse storage rooms 10.

There are preferably motorised louvers fitted inside the remote room 8 to ensure the correct mass flow rate of the discharge air 12, and also the correct mass flow rate of the return air 16 and the inlet air 17 entering the evaporator coils 7.

The whole of the remote room 8 may be acoustically treated to meet noise requirements.

The acoustic insulating material may be mineral wool or a similar material.

The design of the pipes or ducts 11, including the selection of the material used, preferably takes into consideration all the necessary criteria such as, but not limited to, velocity, pressure, temperature and noise, to ensure the correct mass flow rate of the cold air is delivered to the shop floor display units 9 and the storage rooms 10.

The pipes or ducts 11 may be acoustically treated and insulated to minimise temperature loss, condensation, and outbreak of noise caused by air movement along the ducts. The acoustic matenal may be mineral wool or a similar material.

Mechanical fans 18 complete with electric motors are preferably fitted to control the mass flow rate of air into the shop floor display units 9 and the storage rooms 10.

The cold air leaving the remote insulated room 8 is preferably treated with filters and driers to improve the air quality prior to entering the shop floor display units 9 and the storage rooms 10.

The cold air leaving the insulated remote room 8 also preferably passes through noise absorbing material 14 to dampen the noise in the pipes or ducts prior to entering the shop floor display units 9 and the storage rooms 10.

The air leaving the insulated remote room 8 also preferably passes through a filter 15 to remove impurities, especially if ambient air 17 is being brought in from outside the supermarket, before delivery of the air to the supermarket shop floor area (since the air will come into contact with members of the public and food produce etc.).

The storage rooms 10 in the warehouse or stockroom are constructed from standard refrigeration industry insulated panels.

The shoo floor dis !av units Cold Inlet air 26 is delivered from the remote room 8 to the specially-constructed shop floor display unit 9.

The shop floor display unit 9 is coil-free, that is to say, it does not employ an evaporator coil.

As illustrated in Figure 2, the shop floor display unit 9 preferably comprises: a stock display region, in which perishable stock is displayed for selection by customers; a cold air inlet 25, for receiving a supply of cold air 26; a plenum chamber 19 in communication with the cold air inlet 25;

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a discharge chamber 20 in communication with the plenum chamber 19, the discharge chamber 20 incorporating a plurality of air discharge outlets arranged to deliver cold air into the stock display region; a return chamber 21 arranged to receive air from the stock display region, the return chamber 21 incorporating a plurality of air return inlets arranged to receive air from the stock display region; a second chamber 29 in communication with the return chamber 21; and an air return outlet 27 in communication with the second chamber 29, for receiving return air 28 to be returned to the remote room 8.

The shop floor display unit 9 may also comprise supporting uprights 22 and a back panel 23, and merchandising accessories such as shelves 24 within the stock display region. Such uprights 22 may be used to provide support to the display sheMng 24 and the back panels 23, and also to give the display unit modular flexibility and capability.

The configuration of the ducting 11 and its connection to the shop floor display unit 9 Is vely important It would be desirable for the delivery speed of the air into the display unit 9 to be slow and gentle (e.g. 0.4 to 0.8 ms'), in order to avoid wastage of cold air spilling out of the display unit and into the shop floor space. However, this would necessitate using inlet ducts of an unacceptably large diameter. In order to address this, smaller diameter inlet ducts are used, with higher pressure, higher velocity air. This high pressure rapid airflow can cause undesirable noise to be produced in the ducting. This problem is addressed in the present system by the use of a noise filter 14, and/or by cladding the ducts with noise insulation material, and/or by treating the cold air inlet and outlet fans 18 with noise insulation material.

At the shop floor display unit 9, the cold air inlet 25 is arranged such that the incoming air 28 flows into the plenum chamber 19 without encountering any obstacles, since any obstacles may cause back-pressure and could lead to turbulence or dead air spaces within the plenum chamber19. Thus, there is minimum resistance to the incoming air 26, to ensure even distribution within the plenum chamber 19, which in turn optimises airflow out of the plenum chamber and into the stock display region. One way of achieving this is for the cold air inlet to be arranged vertically, parallel to the back panel 23. (This is in contrast to the arrangement in Figure 2 of EP 0689017 Al, in which the incoming air is directed horizontally perpendicular to the back panel of the stock display region. Such air would be expected to become turbulent against the back panel, and unevenly distributed, and could give rise to the formation of dead air spaces.) Altemath,ely the cold air inlet 25 could be arranged to enter the side of the plenum chamber 19, horizontally and parallel to the back panel 23.

Thus, the inlet 25 and exit 27 points on the shop floor display units 9 are not limited to the top (as shown in Figure 2), but may be arranged elsewhere on the unit.

As shown in Figure 3, the cold air inlet 25 is in communication with the plenum chamber 19.

The air return outlet 27 is in communication with the second chamber 29. A solid plate 30 separates the plenum chamber 19 from the second chamber 29. The pipe connecting the air return outlet 27 to the second chamber 29 may pass through a hole in the separating plate 30. Alternatively the bottom end of the pipe from the air return outlet 27 to the second chamber 29 may terminate at the said hole in the separating plate 30.

The plenum chamber 19 and the second chamber 29 are both preferably thermally insulated, to minimise heat loss from both chambers.

A fan 18 may be provided at the cold air inlet 25 to help draw incoming air 28 into the plenum chamber 19. Similarly, a fan 18 may be provided at the air oudet 27 to help draw return air 28 out of the second chamber 29. The fans 18 are of an appropriate size to ensure even and balanced airflow in the display unit 9. The fans are preferably motorised and electronically controlled, and electronically linked to draw air out of the display unit at the same rate as air is drawn in. Thus, an even distribution of air is supplied inside the plenum chamber 19. Moreover, by being electronically linked, the fans 18 ensure the air flow balance is correct between the plenum chamber 19 and the second chamber 29 for the display unit to work optimally, and provide an even and balanced airflow through the display unit and the refrigeration system in general. Operation of the fans may be controlled by one or more temperature sensors positioned in the stock display region of the display unit 9 and/or temperature sensors positioned in the plenum chamber and second chamber.

The fans 18 on the cold air inlet 25, and/or the fans on the air outlet 27, may be electronically linked to the compressor plant I, and configured to shut of one or more compressors in the compressor plant I if operation of the said compressor(s) is/are not required.

The fans 18 may be fitted just outside the shop floor display units 9, and since these units are present within the supermarket shop floor, they cannot be too noisy. Consequently, the fans 18 may be acoustically treated to ensure the noise level is kept to an acceptable level, or to comply with the supermarkef a desired noise level specification on the shop floor. The material used to acoustically treat the fans 18 may be mineral wool or a similar material

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The cold air in the plenum chamber 19 is discharged into the stock display region of the display unit 9. Such airflow may be through a plurality of air discharge outlets in the back panel 23 of the stock display region, directly in communication with the plenum chamber 19.

However, more preferably, the airflow is alternatively (or additionally) discharged via a discharge chamber 20 that is arranged above the stock display region. The discharge chamber 20 preferably incorporates an array of holes or perforations through which the cold air can flow into the stock display region.

For refrigeration of perishable stock such as milk and other dairy products, the temperature of the cold air in the plenum chamber 19 is about -4 C, thus giving an airflow temperature into the stock display region of about -3 C. On mixing with ambient air from the supermarket shop floor, the temperature of the air in the stock display region is about +1 C.

As shown in Figure 4, one or more fans 31 may be incorporated within the discharge chamber 20 to help draw the required flow of air Into the stock display region. It is intended that air will flow naturally from the plenum chamber 19 through the discharge chamber 20, without the operation of the fans 31, and the fans 31 are simply used as and when required, on a standby basis. For example, the fans 31 can be operated in response to temperature sensors in the stock display region, being turned on if the sensed temperature is too high, to enhance the flow of cold air into the stock display region.

The cold air in the stock display region is returned to the second chamber 29 of the display unit 9. The return airflow may be through a plurality of air return inlets in the back panel 23 of the stock display region, directly in communication with the second chamber 29.

However, more preferably, the airflow is alternatively (or additionally) returned to the second chamber 29 via a return chamber 21 that is arranged below the stock display region. The return chamber 21 preferably incorporates an array of holes or perforations through which the air can flow from the stock display region to the second chamber 29.

Figures 5a and 5b show two alternative possible configurations of return chamber 21. Fans 32 may be provided in the return chamber 21 to provide a supplementary suck of the air from the stock display region into the return chamber 21 and thence into the second chamber 29. It is intended that air will flow naturally from the return chamber 21 into the second chamber 29, without the operation of the fans 32, and the fans 32 are simply used as and when required, on a standby basis. For example, the fans 32 can be operated in response to temperature sensors in the shop floor, being turned on if the sensed temperature is too low, to enhance the flow of cold air away from the shop floor.

The majority of the return chamber 21 may be made of solid plate material, to enable the fans to exert a drawing effect on the return air.

As an alternative to using return chambers as shown in Figures 5a or 5b, no return chamber may be fitted. In such a case, fans 32 may befitted to the back panel of the stock display region, in direct communication with the second chamber 29, to retrieve the air coming down from above.

The plenum chamber 19 and the second chamber 29 may be separate parts of one overall chamber, with the plenum chamber 19 separated from the second chamber 29 by the dividing plate 30. Alternatively, the plenum chamber 19 and the second chamber 29 may be entirely separate chambers.

An important advantage provided by the plenum chamber 19 and the second chamber 29 is that a plurality of display units 9 may be interconnected in a modular manner, end-to-end, and/or back-to-back, such that the plenum chambers of adjacent units are sealed in communication together, and the second chambers of adjacent units are sealed in communication together. This enables a number of display units 9 to be served by a fewer number of cold air inlets 25 and air return outlets 27. For example, a single cold air Inlet 25 can supply air to two adjoining plenum chambers 19, and a single air return outlets 27 can remove air from two adjoining second chambers 29. Having a reduced number of cold air inlets 25 and air return outlets 27 in this manner means fewer ducts (connected to the cold air inlets 25 and air return outlets 27) are required in the supermarket. This in turn enables simpler, quicker, and less expensive installation of the display units, and less pipework or ducting visible to customers within the supermarket.

Naturally, it will be appreciated that the ends of the plenum chamber 19 and the second chamber 29 at the end of a row of one or more display units will be sealed, in order to confine the airflow through the display unit as desired.

The discharge chamber 20 and return chamber 21 may also be adapted to be directly coupled to, and in communication with, the corresponding discharge and return chambers of an adjacent display unit.

The discharge chamber 20 and return chamber 21 may also optionally be detachable if required.

Since the display unit 9 is of a modular form, it can manufactured to occupy non-standard lengths in certain circumstances. For example, between two restricting walls or two restricting columns if standard lengths of display units (for example 6ft, 8ft or 12ft) are used, there may be a gap. However, with the present modular design all the space can be filled with a display unit, hence maximising the selling space for refrigeration which is premium.

The features of being detachable and having the capability to be flexible (i.e. manufactured and assembled to any length) are very advantageous: and are not mentioned in the prior art.

Summary of some of the advantaaes of the Dresent disDlay units and refririeretion system 1. The drainage system used with conventional display units is not required -condensation can be mwiimised by insulating the plenum chamber 19 and the second chamber 29.

2. No defrosting requIred in the display units, by virtue of there being no evaporator coil in the display unit. An added advantage is the removal of temperature increase during the defrost periods.

3. Cleaner, by virtue of there being no evaporator coil in the display unit.

4. Less energy used, by virtue of a more efficient air supply route through the display unit, and the ability to utilise cold ambient air 17 from outside the supermarket (during the winter months or in cold climate countries).

5. Simpler, quicker, less expensive and more flexible to install, remove or alter, by virtue of the modular manner by which the plenum chambers and second chambers of adjacent display units can be joined together.

7. Reduced noise, by virtue of the sound absorbing materials used in the ducting.

8. Minimal maintenance required.

9. Environmentally friendly as there will be less refrigerant in the system.

Von low temperature display units suitable for stocking frozen lbod Figures 6, 7 and 8 show different type of display units suitable for displaying frozen food or ice cream products in a supermarket. These display units operate on the same principle as the display unit 9 descnbed above, i.e. employing a plenum chamber 19 and a second chanber 29, and preferably also a discharge chamber and a return chamber with optional fans. However, for frozen products, the temperature in the plenum chamber may be as low as -24 C. The air may be delivered from the remote room at a temperature of about -30C along ducts; even though the ducts are insulated, the cold air will pick up some heat from the surroundrigs, and by the time it reaches the plenum chamber 19 the air temperature may be -24 C. This gives a nominal operating temperature within the stock display region of -23C.

Because the temperatures used with freezers are so much lower than those for refrigerated goods (e.g. milk and dairy products), freezers will require more energy to operate. In order to save energy, and to avoid wastage of the very cold air, the design of the display units for frozen goods is slightly different than that as illustrated in Figure 2. An example of a frozen food display unit is shown in Figure 6, and has doors 60 (e.g. made of glass) fitted to the front of the stock display region to stop the freezing air from spilling out or mixing with the store's ambient air. The freezing air returns via a return chamber to be used again.

Another example of a frozen food display unit is shown in Figure 7. Again, the construction and design of this unit ensures that the freezing air returns back to a return chamber to be used again. Here, the freezing air travels from one side of the stock display region to the other in a horizontal manner and at a very slow speed, so there is no turbulence, but instead a smooth laminar flow across the top. This type of display unit may be used for selling goods such as chips, peas, frozen vegetables, etc. Fig 8 shows a display unit in which the units of Figures 6 and 7 are combined to form a single unit.

The frozen food display units shown in FIgures 6, 7 and 8 each comprise a plenum chamber for receiving cold air from a remote room, a second chamber for receiving air for returning to the remote room, a discharge chamber and a return chamber. Thus, in principle, they are very similar to the display unit 9 described in detail above, and operate on the same principle of moving air. One difference, though, is that no holes are envisaged in the back panels for air to emerge directly from the plenum chamber; with the frozen food display units, it is envisaged that the air will only emerge from a discharge chamber.

Summary of features and some further oDtional features 1. A refrigeration system where specified generated cold air takes place preferably in a secured remote room 8, complete with one or more adequately sized evaporator coils 7, fans 13 and noise absorbing material 14. This generated cold air is delivered to specially-constructed display units 9 located on the supermarket's sales floor, and may also be delivered to one or more storage rooms 10 located in the warehouse or stockroom. The warmer cold air is returned to the remote room 8 by insulated pipes or ducts 11.

2. The generated cold air is the direct result of the thermodynamic change from high pressure liquid to low pressure vapour inside the evaporator coils 7 and the air loosing its heat as ft passes through the fins of the evaporator coil. This process takes place in a room 8 remote from the specially-constructed display units 9 and storage room(s) 10.

3. The pipes or ducts 11 used to deliver the generated cold air from the remote room 8 to the specially-constructed display units 9 on the shop floor and the storage room(s) 10, and for returning this cold air to the remote room 8, are correctly sized and made from a suitable material to withstand all the operating conditions such as pressure, temperature, humidity and noise, such that the pipes or ducts 11 deliver the correct mass flow rate to the specially-constructed display units 9 and storage rooms 10.

4. The pipes or ducts 11 may be insulated with a suitable material to minimise temperature loss, condensation and outbreak of noise caused by air movement.

5. The pipes or ducts 11 may be fitted with mechanical or electronic valves and mechanical fans 18 with electric motors controlled by sensors to regulate and control the mass flow rate of the air.

8. The remote room 8 may be insulated with a suitable material to minimise the temperature loss and the noise outbreak caused by the equipment inside.

7. The remote room 8 can alternatively be the same housing as the compressor plant 1.

8. The remote room 8 may be fitted with motorised louvers controlled by sensors to regulate the mass flow rate of the discharge air 12, return air 16 and intake air 17.

9. The remote room 8 may be manufactured to house all the mechanical equipment such as the evaporator coils 7, mixing chamber, fans 13, noise absorbing material 14, and dners, and all the necessary electrical accessories.

10. The evaporator coil 7 inside the remote room may be a single coil. Alternatively, the evaporator coil inside the remote room may comprise multiple coils, or be multiple pass or multiple layered.

11. The specially-constructed shop floor display units 9 preferably consist of a plenum chamber 19, a second chamber 29, a discharge chamber 20, a return chamber 21, supporting uprights 22, back panels 23, and merchandising accessories 24.

12. The specialty-constructed display units on the shop floor may be used for chill application where the nominal operating temperature is +1 C, or for freezing application where the nominal operating temperature is -23 C.

13. The inlet 25 and exit 27 points for the delivered air on the specially-constructed shop floor display units 9 are not limited to being positioned on the top of the unit (as shown in Figure 2), but may be arranged elsewhere on the unit.

14. In the specially-constructed display units 9, the plenum chamber 19 and the second chamber 29 are separate, to avoid the mixing of the inlet air 26 and the return air 28.

The inlet air 26 feeds the plenum chamber 19 (in which the air is colder), and the return air is fed into the separate second chamber 29.

15. The discharge chamber 20 and the return chamber 21 may be fitted with mechanical fans complete with electric motors to distnbute evenly and balance the air in the specialty-constructed display unit 9.

16. The specialty-constructed display units 9 may be fitted with noise absorbing material to ensure minimum noise outbreak.

17. The refrigerated storage rooms 10 in the warehouse or stockroom are insulated modular panel rooms, of standard refrigeration industry supply. As the rooms are sealed except when the doors are opened, there is minimal mixing of ambient air with the inlet air. Hence there is no separation between the inlet and outlet air. The fans fitted in the inlet and return ducts are linked operationally to ensure balance in the airflow inside the rooms.

18. The compressor plant equipment I may be of standard refrigeration Industry supply.

Claims

1. A coil-free refrigerated display unit for use in a supermarket, the unit comprising: a cold air inlet, for receiving a supply of cold air; a plenum chamber in communication with the cold air inlet; one or more air discharge outlets in communication with the plenum chamber, arranged to deliver cold air into a stock display region in use; one or more air return inlets, arranged to receive air from the stock display region in use; a second chamber in communication with the said one or more air return inlets; and an air return outlet in communication with the second chamber.

2. A display unit as claimed in Claim 1, further comprising a discharge chamber in communication with the plenum chamber, the discharge chamber incorporating at least one of the said one or more air discharge outlets.

3. A display unit as claimed in Claim 2, wherein the discharge chamber is above the stock display region.

4. A display unit as claimed in Claim 2 or Claim 3, wherein the discharge chamber incorporates means for enhancing airflow through the discharge chamber.

5. A display unit as claimed in Claim 4, wherein the means for enhancing airflow through the discharge chamber comprise one or more fans.

6. A display unit as claimed in any preceding claim, further comprising a back panel behind the stock display region, said back panel incorporating at least one of the said one or more air discharge outlets.

7. A display unit as claimed in Claim 6, wherein the back panel forms a wall of the plenum chamber.

8. A display unit as claimed in any preceding claim, comprising a back panel behind the stock display region, said back panel incorporating at least one of the said one or more air return inlets.

9. A display un as claimed in Clam 6, Claim 7 or Claim 8, whereIn the back panel forms a wall of the second chamber.

10. A display unit as claimed in any preceding claim, further comprising a return chamber in communication with the second chamber, the return chamber incorporating at least one of the said one or more air return inlets.

11. A display unit as claimed in Claim 10, wherein the return chamber is below the stock display region.

12. A display unit as claimed in Claim 10 or Claim 11, wherein the return chamber incorporates means for enhancing airflow through the return chamber.

13. A display unit as claimed in Claim 12, wherein the means for enhancing airflow through the return chamber comprise one or more fans.

14. A display unit as claimed in any preceding claim, wherein the plenum chamber is above the second chamber.

15. A display unit as claimed in Claim 14, wherein the plenum chamber is immediately above the second chamber, the plenum chamber and the second chamber being separated by a separating solid plate.

16. A display unit as claimed in any preceding claim, further comprising means for enhancing airflow through the cold air inlet

17. A display unit as claimed in Claim 16, wherein the means for enhancing airflow through the cold air inlet comprise a motorised fan.

18. A display unit as claimed in Claim 17, wherein the said motorised fan is acoustically treated.

19. A display unit as claimed in any preceding claim, further comprising means for enhancing airflow through the air return outlet.

20. A display unit as claimed in Claim 19, wherein the means for enhancing airflow through the air return outlet comprise a motorised fan.

21. A display unit as claimed in Claim 20, wherein the said motorised fan is acoustically treated.

22. A display unit as claimed in Claim 17 and in Claim 20, wherein the motorised fans are electronically coupled so as to enable them to operate in synchronism with each other.

23. A display unit as claimed in any of Claims 4, 5, 12, 13, 16, 17. 18 or 19. wherein the means for enhancing airflow are responsive to one or more temperature sensors disposed within the display unit.

24. A display unit as claimed in any preceding claim, wherein the cold air inlet is arranged such that airflow entering the plenum chamber is not substantially impeded by any of the walls of the plenum chamber.

25. A display unit as claimed in Claim 24, wherein the cold air inlet communicates vertically with the plenum chamber.

26. A display unit as claimed in any preceding claim, wherein the plenum chamber is adapted to be directly coupled to, and in communication with, the plenum chamber of another such display unit.

27. A display unit as claimed in any preceding claim, wherein the second chamber is adapted to be directly coupled to, and in communication with, the second chamber of another such display unit.

28 A supermarket refrigeration system comprising: a display unit as claimed in any preceding claim; and an air cooling plant remote from the display unit; the air cooling plant being arranged to supply cold air to the cold air inlet of the display unit via a pipe or duct.

29 A supermarket refrigeration system as claimed in Claim 28 wherein the air cooling plant is further arranged to receive air from the air return outlet of the display unit.

30. A supermarket refrigeration system as claimed in Claim 28 or Claim 29, wherein the air cooling plant comprises an inlet for receiving ambient air and introducing such ambient air into the refrigeration system during use.

31. A supermarket refrigeration system as claimed in any of Claims 28 to 30, further comprising a storage room also supphed with cold air from the air cooling plant

32. A supermarket refrigeration system as claimed in any of Claims 28 to 31, wherein the air cooling plant comprises one or more of the following: a compressor, a condenser, a liquid receiver, electrical panels and mechanical and electrical accessories.

33. A supermarket refrigeration system as claimed in Claim 32, wherein the air coohng plant further compnses one or more of the following: evaporator coils, motorised fans, motorised louvers, electrical panels and mechanical and electrical accessories.

34. A supermarket refrigeration system as claimed in Claim 33, wherein the said evaporator coils, fans or motorised louvers are located in a first housing, and the said compressor, condenser and liquid receiver are located in a second housing, the second housing being separate from the first housing.

35. A supermarket refrigeration system as claimed in Claim 34, wherein the first housing is thermally insulated.

36. A supermarket refrigeration system as claimed in Claim 34 or Claim 35, wherein the second housing is thermally insulated.

37. A supermarket refrigeration system as claimed in any of Claims 34, 35 or 38, wherein the first housing is provided with noise Insulation material.

38. A supermarket refrigeration system as clakned in any of Claims 34 to 37, wherein the second housing is provided with noise insulation material.

39. A supermarket refrigerabon system as claimed in Claim 34, wherein the said evaporator coils, fans or motonsed louvers are located in a common housing with the said compressor, condenser or liquid receiver.

40. A supermarket refrigeration system as claimed in Claim 39, wherein the said common housing is thermally insulated.

41. A supermarket refrigeration system as claimed in Claim 39 or Claim 40, wherein the said common housing is provided with noise insulation material.

42. A supermarket refrigeration system as claimed in any of Claims 28 to 41, further comprising thermal insulation around the pipes or ducts.

43. A supermarket refrigeration system as claimed in any of Claims 28 to 42, further comprising noise insulation material around the pipes or ducts.

44. A supermarket refrigeration system as claimed in any of Claims 28 to 43, further comprising an air filter in at least one pipe or duct.

45. A supermarket refrigeration system as claimed in any of Claims 28 to 44, further comprising noise reduction means in at least one pipe or duct.

46. An air cooling plant for a supermarket refrigeration system, having an outlet for supplying cold air to a shop floor display unit, an inlet for receiving air from a shop floor display unit, and an inlet for receiving ambient air.

47. An air cooling plant as claimed in Claim 46, wherein the inlet for receiving ambient air is in communication with the exterior of the supermarket.

48. An air cooling plant for a supermarket refrigeration system substantially as herein S...

described with reference to and as illustrated in Figure 2 of the accompanying drawings.

S S..

S

S. .10 S. * S.

S .5...

S S Lf5

48. A coil-free refrigerated display unit substantially as herein described with reference to and as illustrated in any combination of Figures 2 to 8 of the accompanying drawings.

49. A supermarket refrigeration system substantially as here described with reference to and as illustrated in any combination of Figures 2 to 8 of the accompanying drawings.

50. An air cooling plant for a supermarket refrigeration system substantially as herein described with reference to and as illustrated in Figure 2 of the accompanying drawings.

Amendments to the claims have been filed as follows

1. A coil-free refrigerated display unit for use in a supermarket, the unit comprising: a cold air inlet, for receiving a supply of cold air: a plenum chamber in communication with the cold air inlet; one or more air discharge outlets in communication with the plenum chamber, arranged to deliver cold air into a stock display region in use; one or more air return inlets, arranged to receive air from the stock display * region in use; a second chamber in communication with the said one or more air return I * * * S. inlets; and an air return outlet in communication with the second chamber, wherein the plenum chamber and second chamber are configured to enable a plurality of display units to be interconnected in a modular manner.

4. A display unit as claimed in Claim 2 or Claim 3, wherein the discharge chamber includes one or more fans arranged to enhance airflow through the discharge chamber. 3?

5. A display unit as claimed in any preceding claim, further comprising a back panel behind the stock display region, said back panel incorporating at least one of the said one or more air discharge outlets.

6. A display unit as claimed in Claim 5, wherein the back panel forms a wall of the S...

plenum chamber.

. 7. A display unit as claimed in any preceding claim, comprising a back panel behind the stock display region, said back panel incorporating at least one of the said one or more air return inlets.

8. A display unit as claimed in Claims 5, Claim 6 or Claim 7, wherein the back panel forms a wall of the second chamber.

9. A display unit as claimed in any preceding claim, further comprising a return chamber in communication with the second chamber, the return chamber incorporating at least one of the said one or more air return inlets.

10. A display unit as claimed in Claim 9, wherein the return chamber is below the stock display region.

11. A display unit as claimed in Claim 9 or Claim 10, wherein the return chamber includes one or more fans arranged to enhance airflow through the return chamber.

12. A display unit as claimed in any preceding claim, wherein the plenum chamber is above the second chamber.

13. A display unit as claimed in Claim 12, wherein the plenum chamber is immediately above the second chamber, the plenum chamber and the second chamber being separated by a separating solid plate.

S S.

. 14. A display unit as claimed in any preceding claim, further comprising one or more fans arranged to enhance airflow through the cold air inlet. * .

15. A display unit as claimed in Claim 14, wherein at least one of the one or more fans is a motorised fan.

16. A display unit as claimed in Claim 15, wherein the said motorised fan is acoustically treated.

17. A display unit as claimed in any preceding claim, further comprising one or more fans arranged to enhance airflow through the air return outlet.

18. A display unit as claimed in Claim 17, wherein at least one of the one or more fans is a motorised fan.

19. A display unit as claimed in Claim 18, wherein the said motorised fan is acoustically treated. q-o

20. A display unit as claimed in Claim 15 and in Claim 18, wherein the motorised fans are electronically coupled so as to enable them to operate in synchronism with each other.

21. A display unit as claimed in any of Claims 4, 11, 14, 15, 16 or 17, wherein the means for enhancing airflow are responsive to one or more temperature sensors disposed within the display unit.

22. A display unit as claimed in any preceding claim, wherein the cold air inlet is directed away from the walls of the plenum chamber such that airflow entering the plenum chamber is not substantially impeded by any of the walls of the plenum chamber.

23. A display unit as claimed in Claim 22, wherein the cold air inlet communicates substantially vertically with the plenum chamber.

24. A display unit as claimed in any preceding claim, wherein the plenum chamber is adapted to be directly coupled to, and in communication with, the plenum chamber of another such display unit.

25. A display unit as claimed in any preceding claim, wherein the second chamber is adapted to be directly coupled to, and in communication with, the second chamber of another such display unit.

26. A supermarket refrigeration system comprising: a display unit as claimed in any preceding claim; and an air cooling plant remote from the display unit; the air cooling plant being arranged to supply cold air to the cold air inlet of the display unit via a pipe or duct.

27 A supermarket refrigeration system as claimed in Claim 26 wherein the air cooling S..

plant is further arranged to receive air from the air return outlet of the display unit.

S S'S

28. A supermarket refrigeration system as claimed in Claim 26 or Claim 27, wherein the air cooling plant comprises an inlet for receMng ambient air and introducing such ambient air into the refrigeration system during use. **5** * .

29. A supermarket refrigeration system as claimed in any of Claims 26 to 28, further comprising a storage room also supplied with cold air from the air cooling plant.

30. A supermarket refrigeration system as claimed in any of Claims 26 to 29, wherein the air cooling plant comprises one or more of the following: a compressor, a condenser, a liquid receiver and first electrical panels.

31. A supermarket refrigeration system as claimed in Claim 30, wherein the air cooling plant further comprises one or more of the following: evaporator coils, motorised fans, motorised louvers and second electrical panels.

32. A supermarket refrigeration system as claimed in Claim 31, wherein the said evaporator coils, fans or motorised louvers are located in a first housing, and the said compressor, condenser and liquid receiver are located in a second housing, the second housing being separate from the first housing.

33. A supermarket refrigeration system as claimed in Claim 32, wherein the first housing I...

is thermally insulated. p.

I S *S*

34. A supermarket refrigeration system as claimed in Claim 32 or Claim 33, wherein the :s* 10 second housing is thermally insulated.

S * *

35. A supermarket refrigeration system as claimed in any of Claims 32, 33 or 34, wherein the first housing is provided with noise insulation material.

36. A supermarket refrigeration system as claimed in any of Claims 32 to 35, wherein the second housing is provided with noise insulation material.

37. A supermarket refrigeration system as claimed in Claim 31, wherein the said evaporator coils, fans or motonsed louvers are located in a common housing with the said compressor, condenser or liquid receiver.

38. A supermarket refrigeration system as claimed in Claim 37, wherein the said common housing is thermally insulated. Lfr3

39. A supermarket refrigeration system as claimed in Claim 37 or Claim 38, wherein the said common housing is provided with noise insulation material.

40. A supermarket refrigeration system as claimed in any of Claims 26 to 39, further comprising thermal insulation around the pipes or ducts. S...

41. A supermarket refrigeration system as claimed in any of Claims 26 to 40, further comprising noise insulation material around the pipes or ducts. S..

42. A supermarket refrigeration system as claimed in any of Claims 26 to 41, further :" comprising an air filter in at least one pipe or duct.

43. A supermarket refrigeration system as claimed in any of Claims 26 to 42, further comprising noise reduction means in at least one pipe or duct.

44. An air cooling plant for a supermarket refrigeration system, including an outlet for supplying cold air to a shop floor display unit, an inlet for receiving air from a shop floor display unit, and an inlet for receiving ambient air, the shop floor display unit being a display unit as claimed in any of Claims I to 25.

45. An air cooling plant as claimed in Claim 44, wherein the inlet for receiving ambient air is in communication with the exterior of the supermarket.

46. A coil-free refrigerated display unit substantially as herein described with reference to and as illustrated in any combination of Figures 2 to 8 of the accompanying drawings.

47. A supermarket refrigeration system substantially as herein described with reference to and as illustrated in any combination of Figures 2 to 8 of the accompanying drawings.