VESTERGAARD BJOERN (DK)
| EP0855567A2 | 1998-07-29 | |||
| US5904206A | 1999-05-18 | |||
| US5894885A | 1999-04-20 | |||
| DE1130982B | 1962-06-07 |
| 1. | Car provided with an airconditioning system comprising at least one condenser having a first manifold and a second manifold, and a number of heat exchanging tubes extending in a general parallel relationship between the first and the second manifold, characterized in that each manifold is arranged in a general horizontal plane, the first manifold being used as inlet manifold for the cooling fluid in the system and being located above the second manifold. |
| 2. | Car according to claim 1, characterized in that the condenser is a parallel flow condenser. |
| 3. | Car according to claim 1 or 2, characterized in that the tubes are multiple port extruded tubes. |
| 4. | Car according to claim 3, characterized in that fins are arranged between the parallel tubes. |
| 5. | Car according to any one of the preceding claims, characterized in that each manifold is made of a tube like member forming an endless loop. |
Such a car is generally known.
In the air-conditioning systems used in the known cars the arrangement is such that the manifold are formed by two generally tube-like manifolds, which are positioned with their longitudinal axis in the vertical direction, and the heat exchanging tubes are positioned in a horizontal position.
This relative position of the manifolds and the tubes is generally the cause of somehow increased pressure drop, because the refrigerant is first distributed through the manifolds (vertical) into the heat exchanger tubes (horizontal) and collected in the other manifold (vertical) and once again distributed into heat exchanger tubes (horizontal).
Depending on the number of passages in the heat exchanger above scenario can be repeated more times.
The refrigerant flow follow a zig-zag pattern flowing from the top to the bottom of the heat exchanger.
It is therefor an object of the invention to provide a car as described above in which these problems are avoided.
This object is achieved in that each manifolds is arranged in a general horizontal plane, the first manifold being used as inlet manifold for the cooling fluid in the system and being located above the second manifold.
The second manifold can be used as a receiver for sub-cooled refrigerant. The physical size of the second manifold can therefore have a larger internal volume than the first manifold.
The flow of the fluid is improved by the gravity force, thereby reducing the pressure loss, whereas during the downward movement of the fluid the same is condensating while forming droplets, resulting in an improved heat exchange between the fluid and the surrounding air compared to film condensation.
Preferably the condenser of the air conditioning system of the car is made as a parallel flow condenser so that only a downwardly directed flow of the fluid inside the condenser takes place.
Furthermore the tubes can be advantageously be made as multiple port extruded tubes, fins being positioned between each pair of neighboring tubes.
In order to improve the fluid distribution in the inlet manifold it is preferred to make each manifold of a tube-like member forming an endless loop.
As a result of this configuration it is possible to introduce the fluid to be condensed at one point in the first manifold, whereupon the fluid can flow in both directions and because of the closed loop equalize the flow and pressure conditions in the manifold.
In practice it is possible to use any shape of closed loop for the manifold tube such as round, oval, square etc. , but it is preferred to use a compact configuration, e. g. formed by two parallel tube lengths in close contact to each other and two tube portions interconnecting the two end parts of the tubes. The general cross-section of the tube to be used for the manifold is not critical and well known to the man skilled in the art.