Refrigeration – Intermediate fluid container transferring heat to heat... – Flow line connected transfer fluid supply and heat exchanger
Reexamination Certificate
2000-11-09
2001-10-30
Bennett, Henry (Department: 3744)
Refrigeration
Intermediate fluid container transferring heat to heat...
Flow line connected transfer fluid supply and heat exchanger
C062S457200, C062S530000, C165S046000
Reexamination Certificate
active
06308530
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a ice-filled cold storage means for repeat ed freezing and melting according to the preamble of the main claim. Cold storage means are e.g. used in refrigeration technology more particularly for vehicle cooling and air conditioning.
2. Description of the Prior Art
Vehicles are cooled and air conditioned, because in vehicles the air temperature and humidity can reach values which can impair the concentration of the vehicle driver, which can have an effect on the safety of road traffic. Another reason for air treatment is the comfort of the vehicle occupants and the requirements concerning transported goods.
Vehicles which are not in operation can normally not be cooled or air conditioned, because the cooling and air conditioning system is normally jointly supplied by the vehicle drive. Thus, particularly in the sun, such vehicles can be subject to considerable heating.
The heating effect is particularly critical if the vehicle is occupied and the engine cannot or may not be operated, so that the air conditioning and cooling system cannot function, because the drive is not available for it, which is e.g. the case with vehicles, on ferries, trucks and border crossings, in stop and go traffic or in the case of smog.
The problem of the invention is to provide for such cases a cold storage means. This makes it unnecessary to have a separate drive for cooling or air conditions systems and cooling and air conditioning can take place independently of the operation of the drive engine.
Ice is proposed for the storage means operation, particularly in the case of vehicles. Ice is produced from water or an aqueous solution or mixture (hereinafter merely referred to as water to facilitate understanding).
Among all standard single-component liquids water has both the highest specific heat capacity and the highest specific melting heat. In addition, water is inexpensive and safe. This makes water a suitable storage medium. Due to the high melting heat cold storage by ice (latent energy) is far superior to the storage of cold water (sensible energy) due to the lower volume or weight.
However, also in the ice range water has an abnormal behaviour compared with most other substances. In particular the volume rises in the case of ice formation and then decreases again on undercooling or subcooling the ice. If this volume change cannot be compensated by constructional measures (e.g. by a buffer volume), containers in which ice is produced could burst as a result of the ice pressure.
For weight and space reasons the cold storage means should also be small and light. This requires the complete freezing of the water to ice with the consequence that the volume change on freezing and melting is absorbed in an operationally safe manner.
SUMMARY OF THE INVENTION
According to the invention these limiting conditions have been satisfied by a cold storage means having the features of the main claim. The subclaims give advantageous embodiments of the invention.
The cooling system in the vehicle and which is supplied by the vehicle drive, during operation and within the scope of the available capacity takes over the cooling of the vehicle interior and/or can additionally supply the cold storage means (“charging operation”). Part or all the cooling capacity is used for ice formation (if the water of the cold storage means is heated the water is firstly cooled to the freezing point).
As a function of the regulatability of the cooling system, following freezing, the ice is further cooled (“undercooling”) or the cold supply of the cold storage means is interrupted. In any case the volume of the ice has at least temporarily increased.
As soon as the cold storage means is used for air cooling purposes (“discharging operation”), a heat flow to the ice heats and/or melts the latter. The ice is again transformed into water, which is optionally still warmed. This discharging process is also associated with volume changes.
As a result of the volume changes in charging and discharging operation additional drive forces come into action due to the changed specific volumes, which in particular during discharging operation lead to the melted ice floating in the water. If the cold storage means is completely discharged during each operating cycle (the ice being completely melted), when a charging operation takes place again always the same starting conditions apply under which the ice is initially formed at the coldest point of the cold storage means. This type of charging operation is reproducible and can be constructionally comparatively easily controlled.
However, it is difficult to operate the cold storage means if the ice has not yet completely melted before the cold storage means is again supplied from the cooling system (“partial discharging”). As a result of the buoyancy forces of the ice and optionally as a result of forces from the vehicle operation ice from a partially discharged storage means can collect at points where it leads to additional problems in the case of a repeated charging operation. With energy release through the cooling or refrigerating machine, accumulated ice can locally possibly lead to an increased volume and therefore increased pressure, which is an additional burden on the container construction.
The partial discharge problem can be counteracted in that the cooling is controlled in such a way that there must always be a complete discharge before repeated freezing is allowed. However, this represents a waste of energy and is usually not possible or sensible for time reasons alone, e.g. in the case of motor vehicles.
Thus, the cold storage means of a vehicle must be “cycle-proof”, i.e. all charging and discharging states, including the partial discharge, must be operationally safe over a random number of cycles.
The invention achieves the desired objective with a cold storage means having the features of the main claim, in which the container in which the ice is formed and melted is constructed elastically. Advantageously, there is in particular an elastic sleeve, which by means of an external, dimensionally stable jacket is held in fixed manner in close heat transfer contact with air or some other cooling fluid which is to be cooled and/or dehumidified. On the jacket can be provided ribs or rib segments, depressions or prongs for the purpose of increasing the heat transfer surface.
A preferred embodiment proposes a substantially cross-sectionally circular, elastic sleeve being housed in a surrounding circular, dimensionally stable jacket, in which a circular portion is in the form of a slot in order to permit a volume change to the sleeve in the case of jacket deformation.
It is also proposed that the jacket be constructed with more than one recess and for clamping members to be provided for holding together the segments. The jacket can also be formed entirely by clamping members. It is also proposed that a pipe for the cooling or refrigerating fluid supply be in heat transfer contact with the inside or outside of the jacket. With an arrangement of the cooling fluid pipe in the sleeve, said sleeve can be connected to the pipe in such a way that the sleeve is connected tightly and permanently to the pipe at its inlet and outlet (e.g. by bonding pipe and sleeve).
The sleeve can also have a cushion shape with a pocket for receiving a pipe. A cushion-like sleeve can embrace the cooling fluid pipe in such a way that said cushion is so placed around the pipe that the latter is located in “folds” of the cushion. In this case there is no need for fixing, e.g. by bonding. Through a subdivision of the sleeve into chambers smaller individual volumes are created in which ice is in each case retained. These small volumes can e.g. be represented by longitudinal and/or transverse seams of the cushion- like sleeve. The cushion-like sleeve can be subdivided into small volumes by vulcanization, welding, bonding or sewing.
It is also possible to introduce into the sleeve part of the fluid or some other fluid in the form of capsules. A
Bennett Henry
Integral Energietechnik GmbH
Jiang Chen-Wen
Larson James E.
Larson & Larson P.A.
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