US20070028647A1

US20070028647A1 - Condenser inlet diffuser

Info

Publication number: US20070028647A1
Application number: US11/197,564
Authority: US
Inventors: Jun Wang; Mahesh Naduvath; John Judge
Original assignee: York International Corp
Current assignee: York International Corp
Priority date: 2005-08-04
Filing date: 2005-08-04
Publication date: 2007-02-08
Also published as: TW200706818A; WO2007018605A1; TWI281534B

Abstract

A shell side condenser inlet diffuser for a vapor compression refrigeration system is provided. The diffuser includes an inlet to receive a compressed refrigerant from a compressor of a refrigeration system. A chamber is in fluid communication with the inlet to receive compressed refrigerant, the chamber having an upper side and a lower side and lateral sides bridging the upper and lower sides, the chamber having a plurality of openings to discharge refrigerant inside the condenser. A protrusion is disposed inside the chamber. The protrusion and the chamber are configured and disposed to diffuse and direct a flow of refrigerant from the compressor to inside the condenser, the refrigerant leaving the chamber having a higher pressure level than the refrigerant entering the chamber.

Description

FIELD OF THE INVENTION

The present invention is directed to a refrigerant flow control and pressure recovery device for use with vapor compression refrigeration systems in HVAC applications, and more particularly, is directed to a refrigerant pressure recovery device for use with shell and tube type condensers, where cooling fluids such as water flows through tubes and the refrigerant flows through the shell and is cooled and condensed on the outside surface of the tubes.

BACKGROUND OF THE INVENTION

Condensers are an important component used in vapor compression refrigeration systems in HVAC applications. In one type of condenser, refrigerant vapor enters the shell of the condenser and flows across the outside surface of a plurality of cooling tubes. Each of the tubes contains a cooling fluid (e.g., water) at a lower temperature circulating inside these tubes. As the refrigerant flows outside of the tubes, heat transfer occurs from the refrigerant to the lower temperature fluid circulating inside the tubes, such that refrigerant temperature lowers below the saturation temperature and condenses on the outside of the tubes. The condensed refrigerant exits the condenser in the liquid state and the warmer fluid circulating inside the tubes is typically directed to a cooling tower. The condensed liquid refrigerant from the condenser flows through an expansion device to an evaporator. The two-phase refrigerant in the evaporator enters into a heat exchange relationship with a secondary fluid to lower the temperature of the secondary fluid that is circulated to regulate the temperature of an area inside a structure. The refrigerant liquid in the evaporator undergoes a phase change to a refrigerant vapor as a result of the heat exchange relationship with the secondary liquid and is returned to the compressor where the pressure of the refrigerant vapor is elevated and discharged into the condenser to complete the cycle.
In a typical embodiment of the above system, the refrigerant vapor from the discharge of a compressor enters the shell of the condenser at relatively high velocity. An impingement baffle is typically disposed on the inlet of a shell side condenser to prevent direct impingement of the high velocity refrigerant vapor on the condenser tubes. This direct impingement can cause damage to the condenser tubes, such as by vibration, pitting and erosion. Conventional impingement baffles define an elongate, narrow chamber that directs the incoming refrigerant vapor toward opposed ends of the condenser. While preventing damage to the condenser tubes, the impingement baffle causes a drop in pressure of the incoming refrigerant vapor as compared to the pressure of the refrigerant vapor at the compressor outlet. The compressor needs to compress the refrigerant vapor to a higher pressure to make up this pressure drop with more power consumption, thereby lowering the overall refrigeration system efficiency. In addition, a portion of the incoming refrigerant vapor traveling along the center of the baffle retains its high velocity, resulting in potential tube vibration problems and a phenomenon referred to as “liquid hump.” Liquid hump refers to a rise in the level of the condensed refrigerant liquid in the central portion of the condenser shell as compared to the level at the ends of the condenser shell thereby reducing the effective heat transfer surface area, which can reduce condenser efficiency. Further, the high velocity refrigerant causes undesirable splashing of the liquid refrigerant in the condenser shell.
What is needed is a diffuser at the condenser inlet that smoothly decelerates and transitions incoming refrigerant flow, achieving minimum stagnation pressure losses and maximizes the static pressure recovery from the inlet of the condenser to the exit of the diffuser (which is the pressure inside the shell). For a given condensing saturation pressure and temperature inside the shell, a lower pressure is needed at the inlet to the condenser when using the diffuser of the present invention, thereby reducing the power consumption of the compressor, and thereby improving the system efficiency. In the conventional condenser, there is a drop in pressure across the impingement plate as opposed to the case with the diffuser of the present invention where a static pressure recovery occurs. Alternatively, if maintaining the same compressor discharge pressure, the condensing saturation pressure and temperature inside the shell is higher when using the diffuser of the present invention due to static pressure recovery. Without altering the temperature of the fluid circulating through the condenser tubes to cool the refrigerant, the temperature difference between the two is increased, so that less heat transfer surface is needed to reject the same amount of heat. Using the diffuser of the present invention provides opportunity to use a smaller condenser to achieve the same system efficiency.

SUMMARY OF THE INVENTION

The present invention relates to a diffuser situated at the inlet of a shell side condenser of a vapor compression refrigeration system. The diffuser includes an inlet to receive a compressed refrigerant vapor from a compressor of the vapor compression refrigeration system. A chamber is in fluid communication with the inlet to receive compressed refrigerant vapor. The chamber has an upper side, a lower side and lateral sides bridging the upper and lower sides. The chamber also has a plurality of openings to discharge refrigerant vapor inside the condenser shell. A protrusion is disposed inside the chamber. The protrusion and the chamber are configured and disposed to diffuse and direct a flow of refrigerant from the discharge of the compressor to inside the condenser. The refrigerant leaving the chamber of the diffuser has a higher pressure than the refrigerant entering the diffuser at the inlet of the condenser. The inlet of the diffuser typically is in very close proximity to the compressor discharge.
The present invention further relates to a chiller system including a compressor, a condenser arrangement and an evaporator arrangement connected in a closed refrigerant loop. An inlet is in fluid communication between the compressor and the condenser arrangement to receive a compressed refrigerant vapor from the compressor. A chamber is in fluid communication with the inlet to receive compressed refrigerant. The chamber has an upper side, a lower side and lateral sides bridging the upper and lower sides. The chamber also has a plurality of openings to discharge refrigerant inside the condenser arrangement. A protrusion is disposed inside the chamber. The protrusion and the chamber are configured and disposed to diffuse and direct a flow of refrigerant from the discharge of the compressor to inside the condenser. The refrigerant leaving the chamber has a higher pressure than the refrigerant entering the chamber at the inlet of the condenser. The inlet of the condenser typically is in very close proximity to the compressor discharge.
The present invention still further relates to a condenser including an inlet to receive a compressed refrigerant from a compressor of a vapor compression refrigeration system. A chamber is in fluid communication with the inlet to receive compressed refrigerant. The chamber has an upper side, a lower side and lateral sides bridging the upper and lower sides. The chamber also has a plurality of openings to discharge refrigerant inside the condenser. A protrusion is disposed inside the chamber. The protrusion and the chamber are configured and disposed to diffuse and direct a flow of refrigerant from the discharge of the compressor to inside the condenser. The refrigerant leaving the chamber has a higher pressure than the refrigerant entering the chamber at the inlet of the condenser. The inlet of the condenser typically is in very close proximity to the compressor discharge.
An advantage of the present invention is that it facilitates static pressure recovery of the refrigerant entering the condenser, thereby increasing the pressure of the refrigerant vapor leaving the diffuser compared to the pressure of refrigerant entering the diffuser
An advantage of the present invention is that it increases vapor compression refrigeration system efficiency.
A further advantage of the present invention is that it reduces tube vibration associated with operation of the condenser.
A yet additional advantage of the present invention is that it reduces the level of liquid hump inside the condenser.
Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic showing a refrigeration system using a condenser inlet diffuser of the present invention.
FIG. 2 is an elevation view of a condenser having a condenser inlet diffuser of the present invention.
FIG. 3 is a partial cross section of the condenser and condenser inlet diffuser taken along line 3-3 of FIG. 2 of the present invention.
FIG. 4 is a perspective view of an embodiment of a condenser inlet diffuser of the present invention.
FIGS. 5 and 6 are top views of the condenser inlet diffuser shown in FIG. 4 of the present invention.
FIG. 7 shows overlaid cross sections of the condenser inlet diffuser taken along lines A-A and B-B of FIG. 6 of the present invention.
FIG. 8 is a graph comparing pressure recovery of the refrigerant vapor exiting the compressor and entering the condenser between refrigeration systems with and without an inlet diffuser of the present invention.
FIG. 9 is a graph that shows the gain (or difference) in the saturation temperature of the refrigerant in the condenser corresponding to the increase in pressure of the refrigerant exiting the compressor and entering the condenser.
FIG. 10 is a perspective view of an alternate embodiment of a condenser inlet diffuser of the present invention.
FIG. 11 is an end view of a condenser inlet diffuser of FIG. 10 of the present invention.
FIG. 12 is a partial cross section of the condenser and condenser inlet diffuser taken along line 3-3 of FIG. 2 of the present invention.
Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

DETAILED DESCRIPTION OF THE INVENTION

One embodiment of a refrigeration system 100 using a shell side condenser inlet diffuser 114 of the present invention is shown in FIG. 1. The refrigeration system 100 preferably receives electrical power from an AC power source 102 that drives a drive unit 104, such as a variable speed drive or VSD. Drive unit 104, which is controlled by a control panel 108, drives a motor 106 that likewise drives a compressor 110. Compressor 110 compresses a refrigerant vapor and delivers the vapor to the condenser 112 through a discharge line. The compressor 110 can be any suitable type of compressor, e.g., screw compressor, centrifugal compressor, reciprocating compressor, scroll compressor, etc. The refrigerant vapor delivered by the compressor 110 to the condenser 112 first passes through a diffuser 114, which is discussed in further detail below. Upon entering condenser 112, the refrigerant vapor enters into a heat exchange relationship with a fluid, typically water that is circulated via tubes disposed inside the condenser. This condenser configuration is referred to as a shell and tube condenser, with refrigerant condensing on the outside of the tubes and the fluid (e.g., water) flowing inside of the tubes. The refrigerant vapor undergoes a phase change to a refrigerant liquid as a result of the heat exchange relationship with the fluid. The condensed liquid refrigerant from condenser 112 flows through an expansion device (not shown) to the evaporator 116.
The evaporator 116 can include connections for a supply line and a return line of a cooling load. A secondary liquid, e.g., water, ethylene or propylene glycol, calcium chloride brine or sodium chloride brine, travels into the evaporator 116 via return line and exits the evaporator 116 via supply line. The liquid refrigerant in the evaporator 116 enters into a heat exchange relationship with the secondary liquid to lower the temperature of the secondary liquid. The refrigerant liquid in the evaporator 116 undergoes a phase change to refrigerant vapor as a result of the heat exchange relationship with the secondary liquid. The vapor refrigerant in the evaporator 116 exits the evaporator 116 and returns to the compressor 110 by a suction line to complete the cycle. It is to be understood that the diffuser 114 is applied to shell side condensers of shell and tube type 112 where the refrigerant condenses on the outside of the tubes (shell side) whereas the evaporator 116 used in the system 100 can be of any suitable configuration, provided that the appropriate phase change of the refrigerant in the condenser 112 and evaporator 116 is obtained.
The refrigeration or liquid chiller system 100 can include many other features that are not shown in FIG. 1. These features have been purposely omitted to simplify the drawing for ease of illustration.
Referring to FIGS. 2-3, condenser 112 has an embodiment of an inlet diffuser 114 of the present invention. An inlet pipe 127 connected to the diffuser 114 extends through an upper portion of a shell 113 of condenser 112. Preferably, the inlet pipe 127 is secured to the shell 113, such as by welding, or any other suitable means. Furthermore, the inlet pipe 127 also has the appropriate thickness to permit welding to the shell. At the end of the inlet pipe 127 opposite the diffuser 114 and exterior of the shell 113 of condenser 112 is a flange 130 for connecting the inlet pipe 127 to a corresponding pipe to receive pressurized refrigerant vapor from the compressor 110 (FIG. 1). Adjacent to the end of the inlet pipe 127 inside the condenser 112, the inlet pipe 127 transitions to a flared portion 132. Flared portion 132 helps transition the substantially vertical direction of flow of refrigerant vapor flowing into the condenser 112 along the inlet pipe 127 to flow substantially horizontally upon exiting the diffuser 114. The radius of curvature of flared portion 132 is sized and configured, primarily based on the flow rate of refrigerant and the size of inlet pipe 127, to provide a smooth transition of refrigerant flow which minimizes a swirling or twisting component with respect to the desired direction of flow.
In an alternate embodiment, referring to FIG. 12, a support frame 118 can be used to secure the inlet pipe 127 supporting the diffuser 114. Referring to FIGS. 2-5, flared portion 132, which extends inside the shell 113 of the condenser 112, transitions along a tangency curve 134 to an upper surface 136. It is to be understood that the tangency curve 134 does not necessarily define a circle, nor is the upper surface 136 necessarily planar, as in an alternate embodiment (FIG. 12), upper surface 136 could be coincident with the condenser shell 113, or in a further alternate embodiment, the upper surface 136 could actually be the condenser shell 113. Upper surface 136 defines a pair of lobes 138, 140. Lobe 138 is defined by edges 146, 148 and 150, while lobe 140 is defined by edges 152, 154 and 156. One end of edge 146 is defined by a juncture 142 which is the juncture between edges 146 and edge 152, and preferably, also coincides with the tangency curve 134. The other end of edge 146 is defined by a juncture 168 between edge 146 and edge 150.
Similarly, one end of edge 148 is defined by a juncture 144 which is the juncture between edge 148 and edge 154, and preferably, also coincides with the tangency curve 134. The other end of edge 148 is defined by a juncture 170 between edge 148 and edge 150. Preferably, edges 146, 148 each define outwardly directed curves, or convex profiles with regard to lobe 138, although edges 146, 148 can define non-convex profiles, including linear profiles. By edges 146, 148 having convex profiles or suitable non-convex profiles, it can be shown that any line drawn parallel to a reference line 182 connecting junctures 142, 144 along upper surface 138 between junctures 168, 170 is longer than reference line 182. When the diffuser 114 is installed, the reference line 182 is substantially transverse to the length of the condenser 112. The diffuser 114 is preferably bifurcating the flow of refrigerant vapor entering the diffuser 114 along the inlet pipe 127. Stated another way, the distance between corresponding points along edges 146, 148 parallel to reference line 182 increases as the distance of the parallel lines from the reference line 182, i.e., the parallel lines moving along lobe 138 toward edge 150, increases.
Adjacent to edges 146 and 148 and defined by respective junctures 168, 170 is edge 150. Edge 150 is preferably outwardly directed or convex with respect to upper surface 138. Preferably, the curvature of edge 150 is substantially radial, with the center of curvature being coincident with the center of a projection 176. However, the curvature of edge 150 can also be elliptical.
Similar to lobe 138, lobe 140 is defined by edges 152, 154 and 156, while lobe 138 is defined by edges 146, 148 and 150. One end of edge 152 is defined by a juncture 142 which is the juncture between edges 146 and edge 152, and preferably, also coincides with the tangency curve 134. The other end of edge 152 is defined by a juncture 172 between edge 152 and edge 156.
Similarly, one end of edge 154 is defined by a juncture 144 which is the juncture between edge 148 and edge 154, and preferably, also coincides with the tangency curve 134. The other end of edge 154 is defined by a juncture 174 between edge 154 and edge 156. Preferably, edges 152, 154 each define outwardly directed curves, or convex profiles with regard to lobe 140, although edges 152, 154 can define non-convex profiles, including linear profiles. By edges 152, 154 having convex profiles or suitable non-convex profiles, it can be shown that any line drawn parallel to a reference line 182 connecting junctures 142, 144 along lobe 140 and between junctures 172, 174 is longer than reference line 182. Stated another way, the distance between corresponding points along edges 152, 154 parallel to reference line 182 increases as the distance of the parallel lines from the reference line 182, i.e., the parallel lines moving along lobe 140 toward edge 156, increases.
Adjacent to edges 152 and 154 and defined by respective junctures 172, 174 is edge 156. Edge 156 is preferably outwardly directed or convex with respect to lobe 140. Preferably, the curvature of edge 156 is substantially radial, with the center of curvature being coincident with the center of projection 176. However, the curvature of edge 156 can also be elliptical.
Although in a preferred embodiment lobes 138, 140 are symmetrical to each other about the reference line 182 that is preferably coincident with the apex of the protrusion 176, lobes 138, 140 may have a different line of symmetry, lack a line of symmetry, or be asymmetric to each other.
A lower surface 158 is substantially similar in size and shape as upper surface 136, with lower surface 158 and upper surface 136 being separated by a distance 184 that is configured to yield the most favorable results, primarily based on the refrigerant flow rate. Protrusion 176 preferably extends upwardly from the lower surface 158 to help smoothly transition substantially vertically directed refrigerant vapor flow to substantially horizontally directed refrigerant vapor flow upon leaving the diffuser 114. In a preferred embodiment, protrusion 176 is a right circular cone, with the apex of the cone disposed coincident with the center of the neck 128 of the inlet pipe 127. However, it is to be understood that other protrusion geometries can also be used. Further, while protrusion 176 is affixed to the lower surface 158, the protrusion 176 can also be positioned using any suitable mounting arrangement in the refrigerant vapor flow stream between the upper surface 136 and the lower surface 158, or if the protrusion is large enough in at least one direction, to be positioned between the lower surface 158 and the inlet tube 127.
Extending between and bridging the upper and lower surfaces 136, 158 are lateral surfaces 160, 162, 164, 166. Preferably, lateral surface 160 bridges the upper and lower surfaces 136, 158 between juncture 142 and juncture 168 and lateral surface 164 bridges the upper and lower surfaces 136, 158 between juncture 142 and juncture 172. It is similarly preferred that lateral surface 162 bridges the upper and lower surfaces 136, 158 between juncture 144 and juncture 170 and lateral surface 166 bridges the upper and lower surfaces 136, 158 between juncture 144 and juncture 174. In other words, refrigerant vapor that is directed inside the inlet pipe 127, through the flared portion 132, then between the upper and lower surfaces 136, 158 is substantially constrained to flow through an opening 186 between corresponding edges 150 of the upper and lower surfaces 136, 158 in one direction, and an opening 188 between corresponding edges 156 of the upper and lower surfaces 136, 158 in the other direction.
Referring to FIGS. 6-7, and referring back to the earlier discussion of the increased lengths of lines intersecting edges 146, 148 and edges 152, 154 that are parallel to the reference line 182, lower surface 158 is added having substantially identical edges 146, 148, 152, 154 and a pair of vertical planes that are parallel to the reference line 182 coincident with line A-A and with line B-B. Each of the corners of the cross section cut by the plane coincident with line A-A through the upper and lower surfaces 136, 158 is labeled as “A”, and each of the corners of the cross section cut by the plane coincident with line B-B through the upper and lower surfaces 136, 158 is labeled as “B”. In other words, while FIG. 5 only included the upper surface 136, FIG. 6 includes both upper and lower surfaces 136, 158 and lateral surfaces 146, 162. Therefore, the vertically oriented plane that is coincident with line A-A cutting through the upper and lower surfaces 136, 158 of diffuser 114 defines a cross sectional area defining A-A-A-A. Similarly, the vertically oriented plane that is coincident with line B-B cutting through the upper and lower surfaces 136, 158 of diffuser 114 defines a cross sectional area defining B-B-B-B. As shown in FIG. 7, although not drawn to scale, the area defining B-B-B-B is larger than A-A-A-A. It is shown that the cross sectional area defined by the intersection of a transverse plane with the upper and lower surfaces 136, 158 and lateral sides 160, 162, 164, 166 of the diffuser 114 continually increases as the distance between the transverse plane and the reference line 182 increases.
Stated another way, refrigerant vapor flowing inside inlet tube 127 past the flared portion 134 and between upper and lower surfaces 136, 158 impinges upon the projection or protrusion 176, which conditions the flow of the refrigerant vapor from a substantially vertical direction to a substantially horizontal direction. The refrigerant vapor is then additionally constrained to flow inside the upper and lower surfaces 136, 158 and lateral surfaces 160, 162, 164, 166 toward the opposed ends 150, 156, the cross sectional area defined by these surfaces increasing as the refrigerant vapor flows toward the opposed ends 150, 156.
By virtue of the ever-increasing cross sectional area along the diffuser surfaces, the projection 176 and the flared portion 134, the vapor refrigerant flow is advantageously conditioned and controlled. That is, the flow of refrigerant vapor is turned substantially 90 degrees while keeping flow losses at a minimum.
Before further analyzing the condenser inlet of the present invention, a brief discussion is provided by a modified form of Bernoulli's equation as provided in Equation 1 below, which can serve as an intuitive guide for analyzing such flows:
P ₁/(ρg)+(1/(2g))(U ₁)² =P ₂/(ρg)+(1/(2g))(U ₂)²+Loss [1]
wherein P₁, P₂is the pressure at a location 1 and a location 2, respectively, ρ is the density of the flowing fluid, U₁, U₂is the velocity of the flowing fluid at a location 1 and a location 2, respectively. The (1/(2 g))(U)²term represents the kinetic energy component also referred to as velocity head of the fluid at locations 1 and 2, respectively. The P/(ρ g) component of equation 1 is referred to as the pressure head at locations 1 and 2, respectively. Loss refers to losses occurring in fluid flow, such as by friction. Multiplying each side of equation 1 by (ρg) yields equation 2.
P ₁+(ρ/2)(U ₁)² =P ₂+(ρ/2)(U ₂)²+Loss [2]
The (ρ/2)(U)²term in equation 2 is used by those skilled in the art to evaluate the performance of a diffuser as shown in equation 3
C _P =ΔP/(ρ/2)(U ₀)² [3]
where C_Pis a pressure recovery coefficient, ΔP is the absolute pressure recovery or the static pressure difference between the pressure at the inlet of the diffuser and the pressure at the outlet of the diffuser, and the remaining (ρ/2)(U₀)²term is the total velocity head at the outlet of the compressor. The pressure recovery coefficient is a parameter frequently used to measure the operating performance of the diffuser. The pressure recovery coefficient is a measure of the amount of the total available velocity head at the inlet of the diffuser that is converted into static pressure.
Stated simply, the condenser inlet diffuser of the present invention not only changes the direction of flow of refrigerant vapor from a substantially vertical direction to a substantially horizontal direction with minimal flow losses, but additionally converts a portion of the kinetic energy component to a pressure head or static pressure component as shown in equation 1. That is, the condenser inlet diffuser reduces the velocity of the incoming refrigerant vapor as the refrigerant vapor flows through the inlet diffuser toward the condenser tubes while simultaneously increasing the level of static pressure. By increasing the level of static pressure, the condenser can operate at an elevated saturation temperature, thereby requiring less heat transfer surface to exchange the same amount of heat, due to higher temperature difference between the refrigerant vapor entering the condenser shell and the fluid flowing through tubes inside the condenser shell. Additionally, by reducing the velocity of the refrigerant vapor, the difference in levels of collected liquid refrigerant along a lower portion of the condenser is substantially equalized, i.e., liquid hump is minimized. Further, direct impingement of tubes of the condenser due to the flow of the refrigerant vapor is minimized.
Referring to FIGS. 8 and 9, actual tests were performed on a prototype chiller at different operating loads. The ordinate on the graph shows the difference in pressure between the outlet and the inlet of the diffuser and in the conventional impingement baffle arrangement. The abscissa shows the velocity head based on the vertical component of the velocity through the inlet pipe. The value of the abscissa increases from left to right and corresponds to increasing flow into the condenser. The tests were first performed with the condenser inlet having a conventional impingement baffle arrangement, the same tests being performed after the condenser inlet was retrofitted with an inlet diffuser construction similar to FIG. 4. As shown by FIG. 8, pressure recovery occurs in the diffuser and further includes a smooth deceleration of the flow with little loss of energy.
FIG. 9 shows the overall saturation temperature gain achieved by the inlet diffuser construction as compared to the conventional impingement baffle arrangement. By increasing the saturation temperature of the refrigerant condensing in the condenser without altering the temperature of the fluid circulating through the condenser tubes to cool the refrigerant, the temperature difference between the two is increased, so that less heat transfer surface is needed to reject the same amount of heat. Thus, a smaller condenser with less cost can be used. Alternatively, if the same size of condenser is used, due to the pressure recovery of the inlet diffuser construction, a chiller system incorporating the inlet diffuser construction of the present invention operates more efficiently. Stated another way, the compressor having the inlet diffuser construction can compress refrigerant to a pressure level that is lower than the pressure level that must be produced by the compressor having a conventional impingement baffle arrangement, leading to lower energy consumption.
In addition to permitting more efficient operation of an existing refrigeration system by adding the diffuser of the present invention, while otherwise leaving the remaining system components unchanged, alternate constructions are also possible. That is, a condenser having fewer tubes than the originally installed condenser can be used, at a significant cost savings, while providing comparable operating efficiencies. The reason fewer tubes can be used is because the saturated condensing refrigerant temperature leaving the diffuser of the present invention is increased, due to the pressure recovery provided by the diffuser of the present invention, thereby providing a greater temperature gradient between the tubes and the refrigerant. For example, in one chiller configuration tested, the amount of condenser heat transfer, or tube, surface area was reduced by more than 17%, while operating more efficiently than the baseline configuration. However, it is to be understood that factors such as the size and number of the condenser tubes, types of refrigerant and secondary fluid, alternate inlet diffuser profiles, compressor discharge pipe diameter and operating loads can affect chiller system performance values.
FIGS. 10 and 11 is an alternate embodiment of the inlet diffuser 214 in which the tangency curve 134 is substantially flush with the condenser shell 113 so that the condenser shell 113 defines the upper surface 136 of the inlet diffuser 214. It is to be understood that while the area of the diffuser surfaces increases proceeding in directions away from the neck 128 toward opposed edges 150, 156 of lobes 140, 138, it is not necessary that the surfaces 138, 140 are perpendicular to either of the upper surfaces 138, 140 or lower surface 158. Similarly, surfaces 138, 140 and 158 are not necessarily parallel to each other. Further, it is not necessary that surfaces 160, 162, 164 and 166 are curved.
While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims

1. An inlet diffuser for a condenser of a vapor compression refrigeration system, the inlet diffuser comprising:

an inlet to receive a compressed refrigerant from a compressor of a refrigeration system;

a chamber in fluid communication with the inlet to receive compressed refrigerant, the chamber having an upper side and a lower side and lateral sides bridging the upper and lower sides, the chamber having a plurality of openings to discharge refrigerant inside of a condenser;

a protrusion disposed inside the chamber; and

wherein the protrusion and the chamber are configured and disposed to diffuse and direct a flow of refrigerant from the inlet to the plurality of openings, the refrigerant leaving the chamber at the plurality of openings having a higher pressure level than the refrigerant entering the chamber at the inlet.

2. The inlet diffuser of claim 1 wherein the chamber is disposed inside the condenser.

3. The inlet diffuser of claim 1 wherein the protrusion is a cone.

4. The inlet diffuser of claim 3 wherein the cone is a right circular cone.

5. The inlet diffuser of claim 1 wherein the chamber has a plurality of passageways extending from the protrusion to the plurality of openings, the cross sectional area of each passageway of the plurality of passageways increases as the passageway extends toward the plurality of openings.

6. The inlet diffuser of claim 1 wherein the chamber and protrusion condition the flow of compressed refrigerant entering the condenser in a substantially horizontal direction with minimal flow losses.

7. The inlet diffuser of claim 6 wherein the velocity of the flow of refrigerant leaving the chamber is less than the velocity of the flow of refrigerant entering the chamber.

8. The inlet diffuser of claim 1 wherein an end of the inlet adjacent the chamber includes a flared portion.

9. The inlet diffuser of claim 8 wherein the radius of curvature of the flared portion is sized and configured to minimize a swirling component of the flow of the refrigerant entering the chamber.

10. A chiller system comprising:

a compressor, a condenser arrangement and an evaporator arrangement connected in a closed refrigerant loop;

an inlet in fluid communication between the compressor and the condenser arrangement to receive a compressed refrigerant from the compressor;

a chamber in fluid communication with the inlet to receive compressed refrigerant, the chamber having an upper side and a lower side and lateral sides bridging the upper and lower sides, the chamber having a plurality of openings to discharge refrigerant inside of the condenser arrangement;

a protrusion disposed inside the chamber; and

wherein the protrusion and the chamber are configured and disposed to diffuse and direct a flow of refrigerant from the inlet to the plurality of openings, the refrigerant leaving the chamber having a higher pressure level than the refrigerant entering the chamber.

11. The chiller system of claim 10 wherein the chamber is disposed inside the condenser.

12. The chiller system of claim 10 wherein the protrusion is a cone.

13. The chiller system of claim 10 wherein the cone is a right circular cone.

14. The chiller system of claim 10 wherein the chamber has a plurality of passageways extending from the protrusion to the plurality of openings, the cross sectional area of each passageway of the plurality of passageways increases as the passageway extends toward the plurality of openings.

15. The chiller system of claim 10 wherein the chamber and protrusion condition the flow of compressed refrigerant entering the condenser arrangement in a substantially horizontal direction with minimal flow losses.

16. The chiller system of claim 15 wherein the velocity of the flow of refrigerant leaving the chamber is less than the velocity of the flow of refrigerant entering the chamber.

17. The chiller system of claim 10 wherein an end of the inlet adjacent the chamber includes a flared portion.

18. The chiller system of claim 10 wherein the radius of curvature of the flared portion is sized and configured to minimize a swirling component of the flow of the refrigerant entering the chamber.

19. The chiller system of claim 10 wherein during operation of the condenser arrangement, the chamber is configured to provide a substantially equalized level of collected liquid refrigerant along a lower portion of the condenser arrangement.

20. The chiller system of claim 10 wherein direct impingement of tubes of the condenser arrangement by flow of refrigerant vapor entering the condenser arrangement is minimized.

21. A shell and tube condenser comprising:

a protrusion disposed inside the chamber; and

22. The shell and tube condenser of claim 21 wherein the chamber is disposed inside the condenser.

23. The shell and tube condenser of claim 21 wherein the protrusion is a cone.

24. The shell and tube condenser of claim 21 wherein the cone is a right circular cone.

25. The shell and tube condenser of claim 21 wherein the cross sectional area of the upper, lower and lateral sides of the chamber increases toward the plurality of openings.

26. The shell and tube condenser of claim 21 wherein the chamber and protrusion condition the flow of compressed refrigerant entering the condenser in a substantially horizontal direction with minimal flow losses.

27. The shell and tube condenser of claim 26 wherein the velocity of the flow of refrigerant leaving the chamber is less than the velocity of the flow of refrigerant entering the chamber.

28. The shell and tube condenser of claim 21 wherein an end of the inlet adjacent the chamber includes a flared portion.

29. The shell and tube condenser of claim 21 wherein the radius of curvature of the flared portion is sized and configured to substantially reduce a swirling component of the flow of the refrigerant entering the chamber.

30. The shell and tube condenser of claim 21 wherein during operation of the condenser arrangement, the chamber is configured to provide a substantially equalized level of collected liquid refrigerant along a lower portion of the condenser arrangement.

31. The shell and tube condenser of claim 21 wherein direct impingement of tubes of the condenser arrangement by the flow of the refrigerant vapor is minimized.