FI130125B - Refrigeration unit using outdoor air for refrigeration, and refrigeration unit arrangement - Google Patents

Abstract

The description refers to an ecological cooling unit that cools using outdoor air. The cooling unit's energy consumption can be reduced by using cold outside air to keep the cooling unit's storage space (22) at the desired temperature. This can be accomplished by circulating cold outdoor air in the air space between the interior of the chiller and the insulator in the outer shell (21) to cool the interior (22) of the cabinet. The function of the appliance can be intelligently controlled using temperature-sensing sensors, so that the air circulation starts and stops automatically according to what is most suitable for the cooling unit and its energy consumption.

Description

Refrigeration device and refrigeration device arrangement that utilizes outdoor air for cooling

Field of invention

The invention is related to refrigeration equipment, and especially to energy-efficient refrigeration equipment.

Background

Refrigeration devices, such as refrigerators, can significantly improve the shelf life of perishable products. Nowadays, the refrigerator is a standard equipment in homes and e.g.

In Europe and North America it is in almost every home. In addition, there are refrigerators in workplaces and in institutions and other private and public spaces where meals are served. Refrigeration appliances are a very significant group of appliances in terms of energy consumption, which is why by improving their energy efficiency, significant energy savings can be achieved both on an individual and societal level.

Publications DE 102008042814 A1, US 5743109 A, DE 4114915 A1, and JP $5332456 A describe refrigerating devices with a cooling arrangement that circulates outside air or air from another cool space with a pump.

Quick description

The subject of the invention is a refrigerator that utilizes outdoor air for cooling and a refrigerator arrangement comprising such a refrigerator. The refrigerating device and the refrigerating device arrangement according to the invention are characterized by what has been shown independently

N in the patent claims.

O 25 The energy consumption of the refrigerator can be reduced by utilizing the cold outside air to keep the storage space of the refrigerator at the desired temperature. It can be implemented by circulating cold outdoor air in the air space between the interior of the refrigerator and the insulation in the outer shell so that it cools the interior of the cabinet. The operation of the device can be controlled intelligently with the help of sensors that detect the temperature, so that 2 30 — the air circulation starts and stops automatically according to what is intended

N most suitable in terms of the refrigerator and its energy use. In regions with a cool climate

N by utilizing the outdoor air, significant energy savings can be achieved. For example, throughout Finland, the cold can be used to cool the refrigerator for at least 6 months of the year, and in northern Finland even longer. Winters are cold in many southern regions as well, and there are also areas, e.g. in the mountains, where the nights are especially cold.

The outdoor temperature is lowest in winter and at night, when it is both cold and dark. In the warm seasons, when the outside air is too warm to cool the refrigerator, there is a lot of light, thanks to which ecological solar energy can be used to cool the refrigerator.

In severe frosts, the refrigerator can operate completely without external energy. Society's total energy need is at its greatest during the freezing seasons due to the energy required for heating, and to produce it, all (including less environmentally friendly) production methods have to be used. The energy consumption peak can be reduced if the refrigeration equipment does not need electricity at all, or only very little, in freezing weather.

The refrigerating device and refrigerating device arrangement according to the invention can be used — anywhere in the world in areas where the outside temperature drops below the refrigerator temperature for a significant period of the year. It can also be used in areas where the nights are cold, even if the daytime temperatures are high. — Catalog of Pictures

In the following, the invention is explained in detail with reference to the accompanying drawings, in which:

AN 25 Figures 1a and 1b show an application form of this description

From a typical refrigerating device, = Figure 2 shows another application form of a refrigerating device according to this description and

Figure 3 shows yet another application form of the > 30 — refrigerating device according to this description. 2

S

Detailed description

This description describes an energy-efficient refrigeration device and a method of controlling it. The refrigerator has a storage space arranged inside the thermally insulated outer shell for cold storage of the products and a refrigerating machine to lower the temperature of the storage space to the temperature range determined by the minimum temperature and maximum temperature.

The thermally insulated outer shell refers to the whole formed by the thermally insulated walls surrounding the storage space. The desired storage temperature depends on the intended use of the refrigerator. A cold appliance can be, for example, a refrigerator or other storage space equipped with refrigeration equipment, such as a wine cabinet or a cool cabinet. In the case of a refrigerator, the desired storage temperature range can be, for example, +2 °C — +6 °C. In order to improve energy efficiency, an air space is arranged in the outer shell of the refrigerator between the storage space and the thermally insulated outer shell.

Air space is the space or air ducts surrounding the storage space at least partially. Figures 1a and 1b show an application form of such a refrigerator.

Figure 1a shows a simplified cross-sectional diagram of the refrigerator 10 viewed from the front. The cooling device 10 can be, for example, a refrigerator. Figure 1b shows the same cooling device 10 as shown from the side. In Figures 1a and 1b, there is a storage space 12 arranged inside the outer shell 11 comprising thermal insulation 11.1. In Figure 1b showing a side view, a refrigerating device 17 arranged to cool the storage space is also shown.

The storage area is surrounded by air space 11.2. The air space 11.2 is placed between the storage space 12 and the heat separation 11.1 of the outer shell. Between air space 11.2 and storage space 12

AN 25 — wall 12.1 is preferably a material that conducts heat well, such as aluminum. Thus

O it can be ensured that heat is transferred well between the storage space 12 and the air space = 11.2. At the same time, because the thermal insulation 11.1 of the shell 11 is exposed to the air space 11.2 and the air outside the shell 11 (such as room air), the air outside the shell 11 = does not significantly heat the air in the air space 11.2. The wall between the storage space 12 and the air space 11.2 > 30 — can also be formed in such a way that it functions as a heat accumulator. A sufficiently thick wall can, for example, act as a spare cooling plate. Exchange

Optionally or in addition, separate heat accumulators can be arranged in the refrigerator,

N like heatsinks. The heat accumulators can be cooled, for example, during cold nights, when they help to cool the storage space 12 at other times of the day.

The air space in the shell of the cooling device according to this description is connected to an inlet and outlet air pipe to organize the air circulation path to the air space. In Figures 1a and 1b, the inlet air pipe 13 is in the lower part of the cooling device 10 and the outlet air pipe 14 is in the upper part. The air flow in the air circulation path is shown in figures 1a and 1b with arrows. Cold — or cool outside air is absorbed into the intake air pipe 13 and continues from there into the air space 11.2. In the air space 11.2, cold or cool air cools the storage space 12 via the wall 12.1 and then continues heated through the air space 11.2 to the exhaust air pipe 14. The heated air exits the exhaust air pipe 14 to the outside air.

The refrigerator also has measuring instruments for measuring the outside temperature, the air space arranged in the shell and the temperature of the storage space. The measuring devices can be, for example, in the form of temperature sensors. There are preferably at least three sensors, as for example shown in figures 1a and 1b. The first sensor 15.1 can be outside the building or in the supply air pipe 13 as close as possible to the outer wall, where it detects the outdoor air temperature. The second sensor 15.2 can be in the air space of the refrigerator, — where it detects the temperature of the air space 11.2. The third sensor 15.3 can be inside the refrigerating device, where it detects the temperature of the interior space 12 of the refrigerating device.

In order to adjust the air circulation in the air space, the cooling device according to this description still has air flow control means arranged in connection with the inlet and/or outlet air pipe. These adjustment means can be implemented in many ways. They can be — for example, a closing mechanism in the form of a valve or valves. A simple example of a shutter mechanism is a flap operated by an electric motor, which can be set to two different positions (closed and open). In Figures 1a and 1b, such flaps 16.1 and 16.2 function as adjustment means.

The refrigerating device also has control means adapted to control the refrigerating

N 25 — fan and air flow control devices in response to the measured temperatures. outdoor

The air is circulated in the space between the interior of the refrigerator and the insulated outer shell so that the air circulation in the room can be automatically adjusted according to the outside temperature, the temperature of the air in the refrigerator, and the interior temperature. Control devices can be e.g.

I figured it out in the form of an electronic control unit. The control unit can have a computing unit > 30 — (such as a processor, microcontroller or programmable logic) and memory. You can remember

S be a stored program that programs the calculation unit to control the refrigeration equipment and = air flow control devices. The control unit can be programmed to receive

N measurement data from measuring instruments and to decide based on how the refrigeration equipment and air flow are used for cooling. The alternatives are the cooling of the refrigerator only with the help of an externally led air flow, only with the help of the refrigerator's own cooling system, or with a combination of these. If the temperature inside the refrigerating device drops to the lower limit of the desired temperature range, the cooling of the refrigerating device is stopped completely until cooling is judged to be necessary again. 5 With the help of temperature sensors, the refrigerator is intelligently controlled so that the air is recirculated when air recirculation is useful for cooling the interior. As a general rule, the air is circulated when the outside air temperature is lower than the air space temperature. Air circulation is stopped when the outside air temperature rises so high that air circulation is no longer beneficial in cooling the refrigerator. — In one form of application, the control means of the refrigerating device are adapted to control the refrigerating machine and the air flow control means in such a way that the temperature of the storage space is primarily cooled by the air flow. When the outside air is too warm to keep the refrigerator in the desired temperature range, the refrigerator is used. The refrigerator can also be adjusted to use both air flow and refrigeration equipment at the same time.

This is appropriate, for example, when the refrigerator has just been filled with warm food and the temperature of the refrigerator's storage compartment has risen above the maximum temperature of the desired temperature range. In this case, it is important to cool the interior to the desired temperature as quickly as possible.

When the outside air temperature rises so high that the air circulation is no longer useful, the air circulation stops automatically and the air circulation openings close tightly. The completely tight air space insulates heat well, thus improving the thermal economy of the refrigerator.

In the refrigerator, the desired minimum temperature of the storage space is usually around +2 °C and it is important that the temperature does not drop too low, causing freezing. When the outside air is

N 25 — very cold, prevents the programmed cooling device from stopping excessive cooling of the interior

By starting the air circulation automatically when the temperature drops to the lower limit of the desired = temperature range. In this case, no cooling method is used until the temperature of the storage space has risen above the minimum temperature of the temperature range, in which case

I the air circulation starts again. > 30 Air circulation can be arranged in different ways. In one embodiment, the

Gravitational air circulation is encouraged. Gravity air circulation can be the easiest = arrange when the cooling device is placed against the outer wall of the building. Air

N is made to move by gravity when outside air is brought into the lower part of the refrigerator and the air outlet can be arranged in the upper part of the refrigerator. Air circulates vertically,

because warmed air rises upwards. The air moves by gravity when the air comes from below and leaves from above and the air inlet and outlet are far enough from each other and the horizontal drafts are short. The refrigerator can also be equipped with a fan that enhances gravity ventilation. The cooling device's control means can be — determined to identify when it is advisable to assist the gravitational air circulation with a fan. The fan can be low-powered, with a nominal power of less than 2 W, for example. The example in Figures 1a and 1b represents an application form based on gravity-driven air circulation. The supply air pipe 13 is in the lower part of the refrigerating device 10 and the exhaust air pipe 14 is on the top of the refrigerating device 10. Figure 1b shows that the cooling device 10 is placed in the immediate vicinity of the wall 18.

If the cooling device is far from the outer wall, it can be challenging to achieve gravity-driven air circulation. In this case, the cooling device can comprise a fan, which takes the majority of the air flow or the air flow in its entirety. In this type of application, the refrigerator cannot function completely without electricity, but the electricity required by the fan is very little. When the air flow is produced by a fan, the inlet and outlet air ducts do not necessarily need to be placed separately, but they can be close to each other, which means that the ducts can be run in parallel or on top of each other in the interior. Figure 3 shows a schematic view from the front of such an application form.

Air circulation can also be implemented using the building's ventilation system. In some applications of the cooling device, the exhaust air pipe of the cooling device can, for example, be adapted to be connected to the exhaust air duct of the building's ventilation system. Ventilation can be gravity-fed, equipped with mechanical exhaust ventilation or it can be fully mechanical. In gravity exhaust air exchange, the exhaust air duct pulls air out most strongly when the outside air is clear

N 25 — reacts colder than indoor air. The exhaust air duct therefore draws the best

O loin when outdoor air can be used to cool the refrigerator. In gravity = exhaust air exchange, the air circulation can be enhanced if necessary with a low-power blower.

I In buildings with mechanical exhaust ventilation or fully mechanical > 30 ventilation, the air circulation is made to work by the negative pressure produced by the machine

S, and a separate fan is not necessarily needed in connection with the cabinet at all. = Figure 2 shows an example of such an application form. In figure 2, the brochure

Here is a side view of the refrigerator 20 placed next to the outer wall 28. Similar to Figures 1a and 1b, air is brought from the outside to the lower part of the cabinet 20 along the inlet air pipe 23. The refrigerator 20 in Figure 2 has an outer shell 21, an air space 21.2, a storage space 22 and an exhaust pipe 24, as in Figures 1a and 1b. Unlike figures 1a and 1b, in figure 2, however, it is led from the top of the cabinet to the exhaust air duct 24.1. When the exhaust ventilation works mechanically, the air circulation of the refrigerating device can be made to work with the help of the negative pressure produced by the exhaust ventilation without the need for a fan in connection with the refrigerating device.

When the cooling device is used in conjunction with mechanical ventilation, it is advantageous to keep the volume of the air space relatively small, so that the device can be cooled effectively even with a small amount of air. In this case, the variation in recirculation does not really affect the rest of the indoor air exchange or heat recovery.

When the cooling device is a refrigerator, its horizontal dimensions are generally somewhat more than 500 x 500 mm. When the insulation of the shell is subtracted from the external dimensions, the horizontal dimensions of the air space are then less than 500 x 500 mm. If the air is brought from the outside into the lower part of the cabinet with a pipe with a diameter of 80 mm into an air space 100 mm high, is the volume of the air space in the lower part of the cabinet about 25 dm? and the height of the lower part can still be lowered in the back part, in which case its volume can be estimated at about 15 dm?. At the edges of the refrigerator, the thickness of the air space can be, for example, about 10 mm, in which case the air space at the edges is a total of 10-20 dm?3, depending on the size of the refrigerator. In the upper part of the cabinet, the suitable height of the air space can be about 20 mm, so the volume of the air space there is about 5 dm3. The total volume of the air space of the tall refrigerator is thus about 40 dm?. If the air volume is — e.g. 0.8 dm?/s, which means 2880 dm?/h, the air volume is enough to change the air in the entire air space of a large refrigerator more than 60 times per hour, i.e. more than once per minute.

In Figure 3, the refrigeration device 30, which can be, for example, a refrigerator, comprises a storage space 32 and an outer shell 31 surrounding it. The outer shell includes thermal insulation 31.1

N 25 — and airspace 31.2. The storage space 32 and the air space 31.2 are separated from the walls 32.1 by a form-

A sturdy case that defines the storage space. The walls 32.1 are made of heat-conducting material. An intake air pipe 33 and an exhaust air pipe 34 are connected to the air space 31.2. The pipes © 33 and 34 are next to each other in the upper part of the refrigerator 30. The exhaust air pipe 34 has a fan

I 34.1. The air space 31.2 is divided by a partition 31.3 so that through the inlet air pipe 33 > 30 — the incoming air has to circulate around the storage space 32 to reach the outlet air pipe

Step 34. In this way, cool air is obtained to cool the air space 32. The refrigerator 30 has several temperature sensors, similar to the previously presented application forms. first-

The first sensor 35.1 can be outside or in the inlet air pipe 33, the second sensor 35.2 is in the air space 31.2 and the third sensor 35.3 is in the storage space 32. The control means of the refrigerating device are adapted to control the refrigerating device's air flow control means 36.1 and 36.2 as well as the refrigerating machinery according to the temperature data provided by the measuring sensors 35.1, 35.2 and 35.3 on the basis, for example, in the same way as was presented earlier in this description.

A cooling device according to this description can be implemented in many ways, — and the implementation methods are not limited only to the examples presented above.

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Claims (6)

Patent Claims 1. A refrigerator with - — a storage space (22) arranged inside a thermally insulated outer shell (21) for cold storage of products, - — a refrigerating mechanism for lowering the temperature of the storage space (22) to the desired temperature range determined by the minimum temperature and the maximum temperature, - — the said outer shell ( 21), between the thermal insulation of the outer shell (21) and the storage space (22), an arranged air space (21.2), where between the air space (21.2) and the storage space (22) there is a wall made of a material that conducts heat well, and - — connected to the air space (21.2) for arranging the air circulation path of the inlet and outlet air pipe (23, 24) in the air space (21.2), characterized in that the refrigerating device additionally comprises - — measuring devices for measuring the temperatures of the outside temperature, the air space (21.2) inside the shell and the storage space (22), - the inlet and /or the air flow control means arranged in connection with the exhaust air pipe (23, 24) to regulate the air circulation of the air space (21.2), where the supply air pipe (23) is adapted to extend into the outside air outside the building in order to conduct cold or cool outdoor air into the air space (21.2) and the exhaust air pipe (24) is adapted to be connected to the exhaust air duct of the building's air & exchange system (24.1), and N N - — control devices adapted to control the refrigeration equipment and air flow control devices in response to the measured temperatures. I Jam a 25 3 2 2. Refrigeration device according to claim 1, in which the control means are adapted N N - — to receive temperature data from the measuring means about the outside temperature, and about the temperatures of the air space (21.2) and the storage space (22) inside the shell, and - — to control the refrigeration equipment and the air flow control devices based on the temperature data, so that the temperature of the storage space (22) is primarily regulated by means of the air circulation of the mentioned air space (21.2), however, in such a way that if the outside air temperature is not low enough to lower the air space (21. 2) temperature and thus keep the temperature of the storage space (22) below the desired maximum temperature, the temperature of the storage space (22) is adjusted with the help of refrigeration equipment, and if the temperature of the storage space (22) drops to the lower limit of the minimum temperature of the desired temperature range, neither refrigeration equipment nor air circulation is used. 3. Refrigeration device according to claim 1 or 2, where - — the refrigeration device additionally comprises a fan to create air circulation in the air space (21.2). 4. The cooling device according to claim 1 or 2, where - the inlet air pipe (23) is placed in the lower part of the cooling device and the exhaust air pipe (24) is placed in the upper part of the cooling device to enable gravitational air circulation in the air space (21.2). N O N N <Q < 5. A cooling device according to claim 4, where the E - — cooling device comprises a fan adapted to assist gravitational 2 air circulation in the air space (21.2), and the B N 25 - — control means are adapted to assist gravitational air circulation with an O N fan, when the air circulation cools the cabinet air space (21.2) temperature, but the gravitational air circulation is not sufficient to maintain sufficient air circulation in the air space for cooling (21.2). 6. A cooling device arrangement, comprising a cooling device according to one of the preceding claims connected to the exhaust air duct of the building's ventilation system (24.1). O) IN O N N S <t I Jami o O O e) LO N O N