EVAPORATOR UNIT
An evaporator for an air conditioning system includes a plurality of clamshell plates stacked in series along a longitudinal axis and a plurality of core tubes coupled with the stacked clamshell plates. In an upper region of the evaporator, the stacked clamshell plates form an inlet tank and an outlet tank hydraulically communicated with the core tubes for a refrigerant flow. Each of the clamshell plates includes a pooling ridge on a first surface of the clamshell plate for pooling a liquid refrigerant by gravity such that the liquid refrigerant is evenly distributed to inlet core tubes disposed along the longitudinal axis.
Latest Patents:
The present disclosure relates to an evaporator for an air conditioning system, and more particularly relates to refrigerant distribution in a plate type evaporator for the air conditioning system in a motor vehicle.
BACKGROUNDAn air conditioning system for a motor vehicle typically includes a refrigerant loop having an evaporator located within a heating, ventilation, and air conditioning (HVAC) module for supplying conditioned air to the passenger compartment of the vehicle, an expansion device located upstream of the evaporator, a condenser located upstream of the expansion device in front of the engine compartment, and a compressor located within the engine compartment upstream of the condenser. The above-mentioned components are hydraulically connected in series within the closed refrigerant loop.
The HVAC modules rely on the evaporator to provide cooled and dehumidified air to the passenger compartment for passengers' comfort and keeping the windshield from fogging. Starting from the inlet of the evaporator, a low pressure two-phase refrigerant having mixture of liquid and vapor enters the evaporator and flows through the tubes of the evaporator where it expands into a low pressure vapor refrigerant by absorbing heat from an incoming air stream. The evaporator requires even refrigerant distribution for optimum performance and uniform air discharge temperature in the passenger compartment of the vehicle.
Traditional automotive evaporators have two or three refrigerant flow paths in each flow bank. As such, there is minimum number of refrigerant tubes in each path, making refrigerant distribution relatively an easy task. However, for better performance of the evaporator, multipath evaporator systems are developed. The multipath evaporators would require larger tube open area to keep the refrigerant pressure drop reasonably low, as compared to a single path. The required larger tube open area results in larger tube outer dimensions, which cause the airside pressure drop to increase.
Recently, an evaporator with single flow path in each bank has achieved good refrigerant distribution and very low airside pressure drop. The evaporator utilizes a refrigerant distributor tube with evenly spaced orifices. The refrigerant distributor tube is inserted in the inlet manifold for refrigerant distribution. Such a distributor tube is described, for example, in U.S. Published Patent Application No. 2016/0061497 A1.
It has been discovered, however, that the function certain evaporator constructions, such as the one where the refrigerant tubes do not protrude into the inlet manifold, would benefit from improvement.
SUMMARYIt is the object of the present application to provide an evaporator unit in an air conditioning system for a motor vehicle.
According to one aspect of the present disclosure, the evaporator for the air conditioning system includes a plurality of clamshell plates stacked in series along a longitudinal axis. The stacked clamshell plates form an inlet tank and an outlet tank in an upper region of the evaporator. The evaporator further includes a plurality of core tubes coupled with the stacked clamshell plates and hydraulically communicates with the inlet tank and the outlet tank for a refrigerant flow. A pooling ridge is formed on an external surface of at least one of the clamshell plates and configured for pooling a liquid refrigerant by gravity such that the liquid refrigerant is evenly distributed to inlet core tubes disposed along the longitudinal axis.
At least one of the clamshell plates includes an inlet tank opening and an outlet tank opening for forming the inlet tank and outlet tank in the stacked clamshell plates in series along the longitudinal axis. The pooling ridge of the clamshell plate is formed along a bottom edge portion of the inlet tank opening.
According to a further aspect of the present disclosure, at least one of the clamshell plates further includes a rim ridge along top and lateral sides of the clamshell plate, and a center ridge along a vertical axis of the clamshell plate. The rim ridge, the center ridge and the pooling ridge all are formed as a single ridge. The clamshell plate includes an inlet tank opening and an outlet tank opening, and the inlet tank opening is enclosed by the single ridge with a channel along an edge of the inlet tank opening. The channel is formed between the center ridge and the pooling ridge along the edge of the inlet tank opening for allowing the liquid refrigerant to flow out from a liquid refrigerant pool. In addition, each of the clamshell plates further includes a plurality of spherical bumps in a space below the inlet and outlet opening on the first surface of the clamshell plate.
According to a further aspect of the present disclosure, at least one of the core tubes includes an open inlet end and an open outlet end. Both open inlet and outlet ends of the core tubes are inserted into the stacked clamshell plates by an insertion depth in the upper region of the evaporator.
According to a further aspect of the present disclosure, the evaporator includes a distributor tube disposed inside the inlet tank. The distributor tube is configured to receive and expand two phase refrigerant for aliquoting the two phase refrigerant.
According to a further aspect of the present disclosure, the evaporator includes a transition tank in a lower region of the evaporator for hydraulically connecting with the core tubes for the refrigerant flow from the inlet tank to the outlet tank in a lower region of the evaporator. Furthermore, a flow-modulation plate is disposed within the transition tank for aliquoting the refrigerant from the inlet core tubes to outlet core tubes.
According to a further aspect of the present disclosure, the evaporator includes a clamshell housing formed by mating a pair of clamshell plates. The clamshell housing forms a phase change material chamber for serving as a cold storage. Each of the clamshell plates is formed from a sheet of heat conductive material.
According to a further aspect of the present disclosure, the evaporator includes a plurality of fins disposed between and materially joined to the core tubes for facilitating heat exchange.
Further details and benefits will become apparent from the following detailed description of the appended drawings. The drawings are provided herewith purely for illustrative purposes and are not intended to limit the scope of the present disclosure.
In the drawings,
The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.
DETAILED DESCRIPTIONThe following description is merely exemplary in nature and is in no way intended to limit the present disclosure or its application or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.
As shown in
As shown in
In
Referring to
The hybrid plate and tube-fin evaporator 100 with the phase change material chamber 112 is generally used for the vehicle with the second operating mode as described above. The air conditioning system 10 of such a vehicle may be provided with the evaporator 100 having the phase change material to extend the period of cooling to the passenger compartment in the vehicle when the engine 12 is turned off and/or not driving the compressor 16 such as stop-start vehicles or hybrid vehicles.
As shown in
As shown in
As shown in
In
Referring back to
The distributor tube 106 is configured to cooperate with the expansion valve to improve refrigerant aliquoting across the core tubes 108. Generally, the expansion valve 20 expands a liquid refrigerant from the condenser 18 into a first mixture of two phase refrigerant and the distributor tube 106 expands the first mixture into a second mixture of two phase refrigerant. The refrigerant enters the distributor tube 106 as a mixture of liquid and vapor generated by the expansion valve 20 for achieving good refrigerant distribution and very low airside pressure drop.
As an example,
In
As shown in
In
In a conventional design of a hybrid plate and tube-fin evaporator, we have discovered that the vapor refrigerant tends to escape through the first couple of orifices of a distributor tube, carrying certain amount of liquid refrigerant with the vapor because open inlet ends of the core tubes do not protruded into an inlet tank of the evaporator. For the remaining mixture, more liquid pools towards the distal end of the distributor tube due to the different physical properties of the liquid and vapor phases and a separation of the two phase of the refrigerant is occurred. As a result, more liquid is fed to the evaporator core tubes that are further away from the inlet port of the inlet tank, whereas the core tubes at the center section of the evaporator starve of liquid refrigerant, causing a warm zone in the center section of the evaporator.
As described above, in the conventional hybrid plate and tube-fin evaporator, such a refrigerant distribution (e.g., a warm zone in the center section of the core tubes) has been observed under low evaporator load conditions with mid ambient and/or high compressor out pressure (i.e., idle state). Table 1 with data below shows the air outlet thermocouple grid (e.g., 5×5 Outlet Grid) for low airflow idle condition, with the inlet and outlet ports on the left. The warm temperature readings indicate starvation of liquid refrigerant in the center section of the core tubes.
According to the exemplary form of the present disclosure, Table 2 with data below shows the air outlet thermocouple grid (e.g., 5×5 Outlet Grid) for the same condition as Table 1 with the clamshell plates 200 and 201 including the pooling feature of the liquid refrigerant as shown in
While the above description constitutes the preferred embodiments of the present invention, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope and fair meaning of the accompanying claims.
Claims
1. An evaporator for an air conditioning system, the evaporator comprising:
- a plurality of clamshell plates stacked in series along a longitudinal axis and the stacked clamshell plates forming an inlet tank and an outlet tank in an upper region of the evaporator;
- a plurality of core tubes coupled with the stacked clamshell plates and hydraulically communicating with the inlet tank and the outlet tank for a refrigerant flow; and
- a pooling ridge formed on a first surface of at least one of the clamshell plates and configured for pooling a liquid refrigerant by gravity such that the liquid refrigerant is evenly distributed to inlet core tubes disposed along the longitudinal axis.
2. The evaporator of claim 1, wherein at least one of the clamshell plates includes an inlet tank opening and an outlet tank opening for forming the inlet and outlet tanks in the stacked clamshell plates in series along the longitudinal axis, and the pooling ridge of the clamshell plate is formed along a bottom edge portion of the inlet tank opening.
3. The evaporator of claim 1, wherein at least one of the clamshell plates further includes a rim ridge along top and lateral sides of the clamshell plate, and a center ridge along a vertical axis of the clamshell plate.
4. The evaporator of claim 3, wherein the rim ridge, the center ridge and the pooling ridge are formed as a single ridge.
5. The evaporator of claim 4, wherein the clamshell plate includes an inlet tank opening and an outlet tank opening, and the inlet tank opening is enclosed by the single ridge with a channel along an edge of the inlet tank opening.
6. The evaporator of claim 5, wherein the channel is formed between the center ridge and the pooling ridge along the edge of the inlet tank opening for allowing the liquid refrigerant to flow out from a liquid refrigerant pool.
7. The evaporator of claim 1, wherein at least one of the core tubes includes an open inlet end and an open outlet end, and the open inlet and outlet ends of the core tubes are inserted into the stacked clamshell plates by an insertion depth in the upper region of the evaporator.
8. The evaporator of claim 1, wherein the evaporator further includes a distributor tube disposed inside the inlet tank and configured to receive and expand two phase refrigerant for aliquoting the two phase refrigerant.
9. The evaporator of claim 1, wherein the evaporator further includes a transition tank in a lower region of the evaporator for hydraulically connecting with the core tubes for the refrigerant flow from the inlet tank to the outlet tank.
10. The evaporator of claim 9, wherein a flow-modulation plate is disposed within the transition tank for aliquoting the refrigerant from the inlet core tubes to outlet core tubes.
11. The evaporator of claim 1, wherein a clamshell housing formed by mating a pair of clamshell plates forms a phase change material chamber for serving as a cold storage.
12. The evaporator of claim 1, wherein each of the clamshell plates is formed from a sheet of heat conductive material.
13. The evaporator of claim 1, wherein a plurality of fins are disposed between and materially joined to the core tubes for facilitating heat exchange.
14. The evaporator of claim 1, wherein each of the clamshell plates further includes a plurality of spherical bumps in a space below the inlet and outlet opening on the first surface of the clamshell plate.
Type: Application
Filed: Nov 16, 2018
Publication Date: May 21, 2020
Applicant:
Inventors: Gary Scott Vreeland (Medina, NY), Yanping Xia (Williamsville, NY), Edward Wolfe, IV (Clarence Center, NY), Carrie M. Kowsky (Lockport, NY), Lindsey Lee Leitzel (Lockport, NY)
Application Number: 16/193,032