DE2726954A1 - Deep freeze system with latent heat storage - utilises low tariff electricity operating storage utilising latent heat of freezing - Google Patents

Abstract

The deep freezing refrigerator has an electrically driven refrigerator unit, and has a refrigerating storage arrangement making use of latent heat. This storage utilises the cheaper electric power supplied during the night. This arrangement is connected to an electrical switch which connects the refrigerator or in relation to the current tariff or depending on the time of the day. The refrigerator is disconnected at the temperature below the freezing point of the material used in the storage arrangement.

Description

Freezer with cold storage

The method of food at low temperatures for long periods of time to store has become increasingly popular. However, one was also forced Take measures to prevent the risk of food poisoning, which threaten even if the frozen food is thawed for a short time. These There is already a risk when transporting and selling frozen goods, but also e.g. in the event of a power failure that threatens the functioning of the freezers. To such de-energized To bridge times, the freezers are particularly well insulated and heat Also equipped with a cold store to prevent the temperature from rising too quickly to avoid in the device. Depending on the refrigerated goods, -1ß degrees C to -12 degrees C are critical Temperatures viewed.

A particularly effective formation of a cold accumulator is achieved by designing it as a latent cold store. That means you use them so-called heat of fusion of a liquid or a liquid mixture (e.g. Water / alcohol) to store large amounts of heat or cold in small volumes to be able to. For example, 1 Kcal can be used to set the temperature of 1 liter of water change by 1 degree C. But to bring e.g. 1 liter of water from + 0.5 C to - 0.5 C. you have to cool down to 0 C first, then remove another 79.5 Kcal from the water, whereby all the water is converted into ice and only then does the temperature drop below 0 C drop to -0.5 C.

Likewise, when thawing, i.e. melting the ice despite the feed large amounts of heat do not raise the temperature until all the ice has melted.

This advantageous use of a latent cold store is according to the invention combined with an electrical control, which has particular advantages for energy use brings. That Supply of electrical energy is usually in the Night hours are not used, however, every consumption is during the daytime to cope with as an additional capacity-performance peak. The disputed expansion of Nuclear power plants are a drastic example of this problem.

In other areas this problem has already been solved by E.g. for night storage heaters, which are plentiful at night - and also cheap offered - so-called "night power" for heating purposes and during the day the in these stoves give off stored heat to the outside.

The task for the inventive use of night power for deep-freeze purposes differs in essential points from that for night storage heaters. It is not just a matter of storing cold in the event of a system failure To avoid poisoning, but also in the biologically conditioned large supply to provide cold calories around critical temperature ranges during freezing of food possible to "drive through" quickly. In addition there is the additional Problem that in a latent cold storage a temperature measurement during freezing or defrosting with conventional thermostats fails, because in this phase the physical state change no temperature change occurs.

To have the required properties and functions of a freezer to achieve with cold storage for relatively long power breaks is according to the invention proposed that a latent cold storage is provided as a cold store and a electrical switching device is available, which depends on the electricity tariff and / or the time of day the refrigeration machine switches on and depending on the temperature at one temperature the refrigeration machine switches off below the freezing point of the cold storage tank. Through this it is guaranteed that the refrigeration machine only works when the cold storage tank is * full *, that is to say when all liquid is frozen, turn off.

This type of circuit - "on" time-dependent - "off" temperature-dependent- distinguishes this new type of control of the refrigeration machine from a conventional refrigeration system Design type.

Since it is advisable to avoid any power consumption during the day - it unless in the event of danger it is further proposed according to the invention that the Shutdown of the refrigeration machine also depending on the electricity tariff and / or the Time of day takes place. There is a risk that the memory will not be 100 * * filled " but limits the energy intake during the day.

Should there be an impending danger to the frozen in practical use Food result in that for some reason the cold storage thaws and the temperature rises, it is proposed as a safety measure that in parallel to the electrical switching device, which depends on the electricity tariff and / or the time of day the refrigeration machine switches on, another temperature-dependent switching device so to speak, a "hazard thermostat" is present, which at a temperature the is above the freezing point of the latent cold storage, the refrigeration machine switches on.

Because you avoid excessive energy consumption during the daytime hours wants, it is provided according to the invention that during the daytime, if the hazard thermostat " switches on, although it is cooled but no cold is supplied to the cold storage tank, by the further additional temperature-dependent switching device at one temperature the refrigeration machine is set above the freezing point of the latent cold storage switches and at a temperature below, but still above freezing point of the latent cold storage is switched on again.

As a further embodiment of the invention, we proposed that There is a switch that controls the freezer to normal temperature known type switches. This means that you can choose to switch to conventional operation, if as a result of any malfunctions or for other reasons this seems appropriate. For example, the "hazard thermostat" can be used as temperature control be used.

Since different temperature ranges have to be considered, namely the one for an H3 star "refrigerator required - 180 C 0 range, as well as the one mentioned Hazardous areas above - 12 C, it can be advantageous to have several latent cold stores to be provided with different melting temperatures. If frozen food is being stored, which gets by with - 12 C, this measure saves a lot of energy because in such a case you only cool down to the upper - 12 C temperature and in this area the chiller works with better efficiency.

For this purpose, according to the invention, the temperature-dependent switching devices Optionally switchable to the temperature ranges of the different latent cold storage be.

To provide extremely high cooling requirements, e.g. when freezing refrigerated goods being able to do so is in addition to the facilities described above according to the invention Provided that there is a manually operated switch which controls the refrigeration machine switches on continuously.

Since such an extremely high demand for cooling occurs only in exceptional cases and with manually operated switches there is a risk of forgetting to switch off, is proposed as a further improvement according to the invention that a switch is available, which is dependent on the electricity tariff and / or the time of day the refrigeration machine bridged for one or optionally several cycles.

The equipment of freezers according to the invention is in the case of new constructions possible in a simple way. However, there are already hundreds of thousands of these devices as freezers or freezers are in use, there is one according to the invention advantageous Design in that the additionally required latent cold storage and switching devices are designed as a basic kit.

The latent cold storage is e.g. flat plastic containers for this purpose, which are filled with a liquid that freezes at the desired temperature or builds up. Connections or connections are not required, the container are provided in several standard sizes and depending on the shape and size of the freezers simply on the floor or on the walls, or as partitions between the refrigerated goods arranged. This means that an optimal layout is possible for every device. Self-adhesive or adhesive connections on the cold storage tanks make it easier to attach them.

Likewise, the formation of a combined control unit, which all functions combined according to the invention with a display of the selectable switch-on times provided in such a way that all control functions are combined in one unit, which also shows the switch-on times in the form of a timer and in the event of a power failure triggers a warning signal.

Time switches that have no power reserve in the event of a power failure in the wrong rhythm can also switch in cases where the electricity company inserts switching signals Broadcast network to switch the tariff meter according to the invention by a corresponding electronic circuit, which depends on the electricity tariff, must be replaced in such a way that the Switching depending on the electricity tariff by means of control signals from the electricity supply network are overlaid, is triggered.

To explain the function of a cooling device according to the invention with Latent cold storage and low tariff switching are to be described below as exemplary embodiments to be discribed.

Fig. 1 shows a temperature / time circuit diagram like a commercially available one Has cooling device. In more or less regular Cycles, depending also e.g. on the number of door openings or the removal or addition of Chilled goods are in the period shown from 20 h to 24 h of the following Day the cooling machine $ diagram $ diagrams In the example in Fig. 1 is in each case at - 180 C the cooling machine switched on and switched off at - 22 L C. The diagram Fig. 1 and in the following diagrams each show in solid lines (1) the cooling processes with the refrigeration machine switched on and in thin lines (2) the heating processes when the cooling machine is switched off. Repeat the process during the night (3) (low tariff) e.g. from 10 p.m. to 6 a.m. as well as at Time of day (4 (high tariff) e.g. from 6 a.m. to 10 p.m.

Fig. 2 shows the completely different temperature / time diagram of a Cooling device with latent cold storage. Assuming that already a steady state has occurred, only the cold storage cold is supplied or withdrawn, without the temperature rising.

11 Example Fig. 2 is the freezing temperature of the cold storage tank aLt - 200 C assumed.

As soon as, according to the invention, time-dependent after the start of the low tariff E.g. the refrigeration machine is switched on at 10 p.m., it runs the cold storage Cold too, that bites, that which is present in this cold store in a liquid state Refrigerant freezes without changing the temperature in the refrigerator.

First all liquid refrigerant in the latent cold store is frozen is, point (5) of the diagram, the temperature drops further and the chiller switches s.B. at - 220 C temperature-dependent. (Point 6).

Then there is a heating process, as a result of the unavoidable Insulation losses, instead of and the temperature increases until it is reached the melting temperature of the cold storage tank (point 7>. From point 7 onwards, the Do not increase the temperature as the cold storage unit covers the heat losses. Also the Heat losses during the daytime (4) are caused by the heat of fusion of the refrigerant covered.

Only at the beginning of the low tariff in the nighttime (3) is the invention the refrigeration machine is switched on again and supplies gas to the cold store, etc.

Fig. 3 shows a further embodiment of the inventive concept, if by storing refrigerated goods or by other circumstances such as frequent opening of the Door, the cold supplied during the night (3) is insufficient for the storage tank to fill.

The diagram in FIG. 3 shows that in such an example the refrigerator it is switched on all night (3), but the amount of cold supplied is not sufficient sufficient to fill the cold storage. In the example Fig. 3, however, is according to the invention a time or tariff-dependent shutdown provided in point (8), which the Prevents electricity consumption during the daytime (4).

As Fig. 3 shows, of course, in the next cycle at point (9) of the Cold storage its 100 | Achieve ige filling and the further cycle can according to Fig. 2 continue.

4 shows a "hazard example". In this case it is at a time (10) the stored cold is used up and the temperature in the refrigerator increases at.

According to the invention, a temperature-dependent case is used for such a case Switching on at a dangerous temperature, e.g. at - 186 C. In the point (11) this temperature is reached, the refrigeration machine is switched on and the temperature drops again until it reaches the freezing temperature at point (12) of the cold storage tank reached. From point (12) the temperature does not decrease any further, the cold is stored in the cold storage.

Because you have a minimal consumption of energy during the daytime (4), a further improvement is shown in FIG. 5. To during the Time of day (4) to use only the minimum energy required, which is sufficient for damage In the event of danger, avoid switching on the refrigeration machine in the event of danger in point (11) as provided in FIG. 4, but already takes place as a function of temperature at a temperature of e.g. - 180 C, which is above the freezing point of the cold store e.g. - 200 C, the refrigeration machine is switched off.

In this arrangement, Fig. 5, the temperature-dependent circuit operates from the moment of reaching the danger temperature point (11) similar to a conventional one only temperature-dependent control. This Diagranil sequence also corresponds to the emergency circuit ", that for some reason the time or tariff-dependent control over bridged a manually operated emergency switch and only temporarily in conventional Type of temperature-dependent controls.

Fig. 6 shows an example of attachment of the cold storage (14) on the outside of the inner container (13) of a freezer. Thereby the cold storage (14) glued directly onto the evaporator tubes (15) to ensure a good cold transition to reach.

Fig. 7 shows a section of a freezer with subsequently inserted Cold accumulators (14), which are angeordna on the walls and the lid of the chest. That’s also there Use of adhesive connections advantageous. The cold storage (16) is used as a partition and provides better distribution the cold inside the chest.

Fig. 8 shows an example of the design of a control panel (17) as it can also be used for retrofitting an existing freezer can. The device is connected to the electrical network with a plug (18), for example. The freezer is also connected to the device via the plug (19). Included will be an event. Existing control is bridged by opening the freezer Continuous operation switches. The temperature sensor (20) is placed in the freezer, and the control panel (17) takes over all functions according to the invention. The 24 hours Time switch (21), the hatched marked switch-on area (22) with the Button (23) can be set, determines the normal switch-on times in the night-time low tariff.

The temperature selector (24) allows the desired temperature range to be selected. The buttons (254 to (28) have special functions, e.g. button (25) for continuous operation for 1 day cycle, TAste (26) continuous operation for 2 days in the event of freezing larger amounts.

The button (27) could, for example, be used for an unlimited period of time. The button (28) could e.g. be used to switch to normal temperature control, by bridging all time-controlled functions.

The examples given show the significant advantages of this new one Combination of latent cold storage and time / temperature control. Although only applications For cryogenic temperatures are described, is the same use according to the invention possible in refrigerators at temperatures above zero degrees Celsius. Be it that of a Tiefkßhlspeicher air is cooled, which in appropriate amounts is added to the cold room in a known manner in order to obtain the desired temperature, or to use latent cold storage devices directly, which already freeze above 0 C. The method of adding frozen air naturally has the advantage that the temperature can be adjusted.

This invention can be very expensive at a reasonable cost Build up sparingly, but also equip with all the finer points to meet the highest demands suffice.

L e r s e i t e

Claims (12)

Claims "freezer with cold storage" 1) freezer with an electrically driven refrigeration machine, characterized in that as a cold store a latent cold storage and an electrical switching device is available, which depending on the electricity tariff and / or the time of day, the refrigeration machine switches on and temperature-dependent at a temperature below the freezing point of the cold store the chiller switches off. 2) Freezer according to claim 1, characterized in that the shutdown the chiller also depending on the electricity tariff and / or the time of day he follows. 3) freezer according to claim 1 or 2, characterized in that parallel to the electrical switching device, which turns on the cold machine depending on the electricity tariff and / or the time of day, another additional temperature-dependent switching device is available, which is at a temperature above the freezing point of the latent cold storage the refrigeration machine switches on. 4) Freezer according to claim 3, characterized in that further additional temperature-dependent switching device at a temperature above the The freezing point of the latent cold storage unit is switched on and included a temperature below, but still above the freezing point of the latent cold storage lies off again. 5) freezer according to claim 1, 2> or characterized, that there is a switch that sets the freezer to normal temperature control known type. 6) Freezer according to one or more of the preceding claims, characterized in that several latent cold stores with different melting temperatures available. 7) freezer according to one or more of the preceding claims, characterized in that the temperature-dependent switching devices optionally the temperature ranges of the various latent cold stores can be switched. 8) Freezer according to one or more of the preceding claims, characterized in that there is a manually operated switch which the Switches the refrigeration machine on continuously. 9) freezer according to one or more of the preceding claims, characterized in that a switch is available, which the electricity tariff and / or the time of day-dependent shutdown of the refrigeration machine for one or also optionally bridged several cycles. 10) Freezer according to one or more of the preceding claims characterized in that the additionally required latent cold storage and Switching devices are designed as a retrofit kit. 11) Freezer according to one or more of the preceding claims characterized in that all control functions are combined in one unit which also shows the switch-on times in the manner of a timer and in the event of a power failure triggers a warning signal. 12) Freezer according to one or more of the preceding claims characterized in that the circuit dependent on the electricity tariff is controlled by control signals which are superimposed on the power supply network, is effected.