Compact condenser

A compact condenser system has a compact arrangement that also increases the efficiency of the condenser. The compact condenser comprises two heat exchangers fixed opposite each other on a frame and at least one fan is interposed between the heat exchangers so as to draw air through the second heat exchanger and push air through the first heat exchanger while refrigerant flows from the first heat exchanger to the second heat exchanger. Liquefaction of the refrigerant with two opposed heat exchangers increases the efficiency and compactness of the condenser.

TECHNICAL FIELD OF THE INVENTION 
This invention relates to a condenser for liquefying a vapor refrigerant 
received from a compressor. In one aspect, this invention relates to such 
a condenser with a compact arrangement and increased efficiencies that is 
suitable for use in vehicles. 
BACKGROUND OF THE INVENTION 
Present air conditioner condensers typically comprise one heat exchanger. 
Vapor refrigerant is driven by a compressor through the tubes of the heat 
exchanger while air is passed across the tubes to facilitate removal of 
the heat from the vapor refrigerant. Usually there are four to six rows of 
tubes. There is approximately a 20 percent loss in efficiency of heat 
transfer with each successive row of tubes. As the vapor refrigerant 
starts to liquefy in the exchanger, the temperature differential between 
the refrigerant and the air decreases which decreases the rate of heat 
transfer. Accordingly, heat exchangers take up considerable space to 
accommodate the needed lengths of the rows of tubes to insure liquefaction 
of the refrigerant. The large size of the heat exchanger presents problems 
in placing the condenser in limited spaces available in various vehicles. 
Also, as the space inside the vehicle that needs to be cooled increases, 
such as in buses or other larger vehicles, the size of condensers must 
increase which in turn compounds the problem of fitting the condenser in 
the vehicle. 
Thus a need exists for a more compact condenser design that also increases 
the efficiency of heat transfer out of the refrigerant with each 
successive row of tubes. 
SUMMARY OF THE INVENTION 
The present invention provides a compact condenser for use in the air 
conditioning system of a vehicle. The compact condenser comprises a first 
heat exchanger and a second heat exchanger fixed opposite each other in a 
frame such that there is a space between the first and second heat 
exchangers. At least one fan is interposed in the space between the first 
and second heat exchanger such that air is drawn through the second heat 
exchanger and pushed through the first heat exchanger. The heat exchangers 
have a plurality of tubes for passage of refrigerant through the heat 
exchangers. Vapor refrigerant enters the first heat exchanger and exits 
partially liquefied. The partially liquefied refrigerant then enters the 
second heat exchanger where it exits substantially liquefied and ready for 
delivery to an evaporator. 
Use of two heat exchangers in such an arrangement provides two smaller heat 
exchangers instead of one large one. The position of the two smaller heat 
exchangers relative to each other can be varied to facilitate fitting the 
compact condenser in limited and cramped areas. Stepping the heat transfer 
into two heat exchangers contributes to efficiency increases of up to 15% 
depending on the circumstances. 
Therefore, the present invention provides a compact condenser design which 
is more readily fitted within the limited space of vehicles. Moreover, the 
present invention is to provide a condenser with increased efficiency.

DETAILED DESCRIPTION 
Referring to FIGS. 1 and 2, reference numeral 10 generally identifies the 
compact condenser of the present invention used in conjunction with an air 
conditioning system for motor vehicles. Compact condenser 10 comprises 
first heat exchanger 12 and second heat exchanger 14 fixed opposite each 
other with three fans 20 interposed between the exchangers. The vapor 
refrigerant from a compressor enters first heat exchanger 12 at vapor 
refrigerant entrance nozzle 22 of tube 16 for flow therethrough. Tubes 16 
are arranged in tube rows 15 which run through the first heat exchanger 
12. Vapor refrigerant travels through tube rows 15 in first heat exchanger 
12 while air is pushed through first heat exchanger 12 by fans 20. As heat 
is transferred from the refrigerant, the refrigerant begins to liquefy. 
Partially liquefied refrigerant exits the first heat exchanger at 
partially liquefied refrigerant exit nozzle 24. The partially liquefied 
refrigerant then enters into second heat exchanger 14 at partially 
liquefied refrigerant entrance nozzle 26. Partially liquefied refrigerant 
flows through tube rows 15 in second heat exchanger 14 while air is drawn 
through second heat exchanger 14 by fans 20 until the refrigerant is 
substantially liquefied and exits at liquefied refrigerant exit nozzle 28. 
The present condenser is designed for use in a conventional air 
conditioner assembly wherein the refrigerant, upon exiting liquefied 
refrigerant exit nozzle 28, is delivered through an expansion valve and 
into an evaporator where it will eventually be compressed again by a 
compressor to enter first heat exchanger 12 again at vapor refrigerant 
entrance nozzle 22. 
The design and construction of heat exchangers 12 and 14 is of a 
conventional design where tube rows 15 are supported in end plates 18 and 
disposed through and in contact with a plurality of heat transfer fins 19. 
With reference to FIG. 1, direction arrows 34a, 34b, 34c and 34d indicate 
travel of air through compact condenser 10. Direction arrow 34a indicates 
ambient air being drawn towards second heat exchanger 14 where it will 
complete the process of liquefying the refrigerant in second heat 
exchanger 14. The air indicated at direction arrows 34b has been drawn 
through second heat exchanger 14 and is being pushed towards first heat 
exchanger 12. The air at this stage is hotter than the ambient air at 
direction arrow 34a, however, since the temperature of the vapor 
refrigerant in first heat exchanger 12 is so high, there is sufficient 
temperature differential between the vapor refrigerant at first heat 
exchanger 12 and the air at direction arrow 34b to sufficiently liquefy 
the vapor refrigerant travelling through first heat exchanger 12. The air 
at direction arrow 34c has been drawn into fans 20 and is being pushed 
towards first heat exchanger 12. The air indicated at direction arrow 34d 
has finished passing through first heat exchanger 12. This preferred 
arrangement of compact condenser 10 provides a compact design which is 
highly desirable in order to save space in vehicles. Also, it has been 
found that separating the liquefaction process into two different heat 
exchangers generates greater efficiencies of up to 15 percent depending on 
the circumstances. 
Alternatively, more than two heat exchangers can be used. A plurality of 
heat exchangers can be situated so that a single current of air can be 
directed through the heat exchangers in a direction counter to the 
progression of refrigerant through the heat exchangers. The direction 
arrows 34a, 34b, 34c and 34d indicate such a current. As the air current 
proceeds through the heat exchangers, the temperature of the air 
increases. This counter direction of the air insures a sufficient 
temperature differential between the air and refrigerant at each heat 
exchanger. If the air were directed in the direction of the progression of 
refrigerant through the heat exchanger, the temperature differential would 
decrease rendering downstream heat exchangers ineffective. 
The heat exchangers can be tilted at various angles to each other to 
facilitate placement of the condenser in a compact area of a vehicle. Thus 
the present invention provides a compact condenser which can be arranged 
according to the space available for the condenser. In FIGS. 1 and 2, 
first heat exchanger 12 is tilted with respect to second heat exchanger 
14. With reference to FIG. 2, the heat exchangers are fixed relative to 
each other by being mounted on frame 17. Frame 17 can be modified to fit 
into the available space. 
Although the present invention has been described with respect to a 
specific preferred embodiment thereof, various changes and modifications 
may be suggested to one skilled in the art, and it is intended that the 
present invention encompass such changes and modifications as fall within 
the scope of the appended claims.