US20070107453A1

US20070107453A1 - Heat exchanger with embedded heater

Info

Publication number: US20070107453A1
Application number: US11/280,917
Authority: US
Inventors: Gus Cutting; Nicholas Hartney; Winston Webb
Original assignee: Honeywell International Inc
Current assignee: Honeywell International Inc
Priority date: 2005-11-16
Filing date: 2005-11-16
Publication date: 2007-05-17

Abstract

A heat exchanger having both heating and cooling functions includes a first container, a second container and at least one heater. The first container is adapted to hold a first fluid. The second container is adapted to hold a second fluid. Moreover, the second container is thermally coupled to the first container such that thermal energy transfer between the first and second container occurs. The at least one heater is embedded with the first and second container.

Description

TECHNICAL FIELD

The present invention relates generally to heat exchangers and in particular to heat exchangers having both heating and cooling functions.

BACKGROUND

Fluids are used in various industries for certain heating or cooling applications. For example, fluids (liquid or gas) are used in heat exchangers. A heat exchanger is a device used to transfer thermal energy from one fluid to another fluid. The two fluids are held in separate containers that are thermally coupled to each other so that the transfer of thermal energy occurs. In some applications the heat exchangers are designed for both heat exchange and cold exchange. For heat exchange, a heater is typically submerged in an associated fluid which is then activated to heat the fluid as it flows over the heater. The heated fluid is then pumped through the heat exchanger (i.e. through the containers thermally coupled to each other to transfer the heat from the heated fluid to the other fluid). This type of arrangement, however, presents a problem with the separation of control of the energy entering and exiting the system. In particular, this type of arrangement, can cause oscillation at set points and unreliable operation during ramps (i.e. the transition period it takes from going from an initial temperature to a desired temperature). In addition, in very cold dwells or rapid ramps, the cold exchanger can actually freeze the working fluid in the exchanger, stopping all flow. If this happens, no matter how much heat the heating system adds, the cold exchanger will not thaw since there is no flow of the fluids. This forces the system to stop operation until the cold exchanger thaws out on its own. This can take days in large systems causing loss of production and time. Another disadvantage to this type of system is the bulkiness of the total system (i.e. the separate heater and heat exchanger takes up a lot of space). Where space is limited, this type of heat exchanger system is not a viable option.
For the reasons stated above and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for a heat exchange system that is efficient, not as susceptible to the freezing of the working fluid and is relatively small in size.

SUMMARY OF INVENTION

The above-mentioned problems of current systems are addressed by embodiments of the present invention and will be understood by reading and studying the following specification.
In one embodiment, a heat exchange system is provided. The heat exchange system includes a first container, a second container and at least one heater. The first container is adapted to hold a first fluid. The second container is adapted to hold a second fluid. Moreover, the second container is thermally coupled to the first container such that thermal energy transfer between the first and second container occurs. The at least one heater is embedded with the first and second container.
In another embodiment, a method of manufacturing a heat exchanger is provided. The method comprises forming a first thermal container adapted to contain a first liquid. Forming a second thermal container adapted to contain a second liquid. The second thermal container is thermally coupled to the first thermal container. Finally, embedding at least one heater with the first and second thermal containers.
In yet another embodiment, a method of operating a heat exchange is provided. The method comprises generating a flow of a first fluid in a first container. Generating a flow of a second fluid in a second container, wherein the second container is thermally coupled to the first container and adjusting the thermal energy in the first and second fluids with at least one heater that is integrated with the first and second container.
In still another embodiment, a heat exchange system comprises a first means for containing a first fluid and a second means for containing a second fluid. The first and second means being in thermal contact with each other. The heat exchange system also includes a means for heating the first and second fluids with a heater embedded with the first and second means for containing the first and second fluid.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention can be more easily understood and further advantages and uses thereof more readily apparent, when considered in view of the description of the preferred embodiments and the following figures in which:
FIG. 1 is a cross-sectional side view of a heat exchanger system of one embodiment of the present invention;
FIG. 2 is a side view of a heat exchanger system of another embodiment of the present invention;
FIG. 3 is an illustration of a heat exchanger system of one embodiment of the present invention;
FIG. 4 is an illustration of a heat exchanger system of FIG. 3 including a layer of thermally conductive material.
In accordance with common practice, the various described features are not drawn to scale but are drawn to emphasize specific features relevant to the present invention. Reference characters denote like elements throughout Figures and text.

DETAILED DESCRIPTION

In the following detailed description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the inventions may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that logical, mechanical and electrical changes may be made without departing from the spirit and scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the claims and equivalents thereof.
Embodiments of the present invention provide a heat exchanger that has a heater embedded therein. By embedding the heater in the heat exchanger, greater temperature control of the heat exchanger is achieved since the thermal capacitance stored in the cold exchanger is driven away by one or heaters embedded in the heat exchanger rather then simply being transferred to the working fluid. Moreover, a controller of the heat exchanger of embodiments of the present invention does not have to try and compensate for residual cooling potential left in the cold heat exchanger after it is no longer needed. In addition, in embodiments of the present invention, you do not have to wait for the working fluid to pass through the entire system and return before heating the cold exchanger, thus reducing feedback time. This helps to minimize overshoot while ramping to set point as well as oscillation at set point. Embodiments of the present invention also help to prevent the cold heat exchanger from freezing during cold dwells and rapid ramps. Moreover, if the exchanger does freeze and the flow of working fluid is stopped, the heater or heaters can rapidly thaw the exchanger and restore the fluid flow. Finally, embodiments of the present invention provide a heat exchange system that is relatively small in size.
Referring to FIG. 1, a cross-sectional view of a heat exchange system 100 of one embodiment of the present invention is illustrated. As illustrated, the heat exchange system includes a first thermally conductive container 102 adapted to hold a first fluid 106 (gas or liquid) and a second thermally conductive container 104 to hold a second fluid (gas or liquid) (108). In this example of the embodiment of the present invention, the first container 102 is in the form of an annulus that surrounds the second container 104 which is in the form of a pipe. Fluid 106 exchanges thermal energy with fluid 108 in performing the heat exchange function.
FIG. 1, also illustrates heaters 110-1 through 110-N which are embedded in the heat exchange system 100. In one embodiment the heaters 110-1 through 110-N are electrical heaters. Also illustrated in FIG. 1 is controller 112 that is designed to control the electric heaters 110-1 through 110-N. Under control of the controller 112, the thermal capacitance stored in the cold exchanger is selectively driven away by the heaters 110-1 through 110-N embedded in the heat exchanger rather then simply being transferred to the working fluid. The present invention is not limited to the type of heat exchanger 100 illustrated in FIG. 1 since other types of heat exchange systems would benefit from having one or more heaters embedded in the system. Moreover, embodiments of the present invention use different types of heaters which include but are not limited to solid plate heaters, rope heaters, wire heaters and immersion heaters and the like. Accordingly, the present invention is not limited to a specific type of heater.
An example of a different type of heat exchange system 200 incorporating an embodiment of the present invention is illustrated in FIG. 2. As illustrated, the heat exchange system 200 of FIG. 2 includes a first and second container 202 and 204 respectively. The first and second containers 202 and 204 in this embodiment are tubes that are formed into coils. The tubes are made from a material that has relative high thermal conductivity such as copper. The coils of the first and second containers 202 and 204 are positioned next to each other so that thermal energy can be transferred between them. Also positioned next to the coils of the first and second containers 202 and 204 is a heater 206. In particular, in this embodiment, the heater 206 is a wire (or cable) heater that is wrapped around the coils of the first and second containers 202 and 204.
The embodiment of FIG. 2 also includes a thermally conductive material 208 that encases the coils of the first and second container 202 and 204 as well as the heater 206 wrapped around the coils of the first and second containers 202 and 204. The thermally conductive material 208 enhances thermal conduction between the fluids in the coils of the first and second containers and the heater 206. This embodiment further includes a layer of insulation 210 that encases the thermally conductive material 208. The layer of insulation 210 provides further efficiency to the heat exchanger system 200 of FIG. 2, by inhibiting unwanted thermal energy exchange between the heat exchange system 200 and the environment surrounding the system 200.
Referring to FIG. 3, an illustration of a heat exchange system 300 similar to the heat exchange system of FIG. 2 of one embodiment of the present invention is provided. This heat exchange system 300 also includes a first and second container 302 and 304 respectively. The first and second container 302 and 304 are tubes that are formed into coils that are positioned next to each other to achieve thermal transfer. Embedded in the coils is an electric wire heater 306. The connections to the electric wire heater are indicated at 308 and 310. FIG. 4 illustrates the heat exchange system 300 of FIG. 3 including conductive material 408 embedding the coils of the first and second containers 302 and 304 and the embedded wire heater 306. In one embodiment, the conductive material is made from conductive clay that hardens after it is placed around the coils of the first and second containers 302 and 304 and the embedded wire heater 306.
A flow diagram 500 illustrating the operation of a heat exchange system of one embodiment of the present invention is illustrated in FIG. 5. As illustrated, the operation begins by generating a flow of first and second fluids through a respective first and second containers (502 and 504). In embodiments of the present invention the thermal energy in the first and second fluids is adjusted using an embedded heater (506). As discussed above, the embedded heater provides greater temperature control of the heat exchanger since the thermal capacitance stored in the cold exchanger is driven away by the rather then simply being transferred to the working fluid. As a result, you do not have to wait for the working fluid to pass through the entire system and return before heating the cold exchanger, thus reducing feedback time. This helps to minimize overshoot while ramping to set point as well as oscillation at set point. Moreover, the adjusting of the temperature at (506) also helps to prevent the cold heat exchanger from freezing during cold dwells and rapid ramps. In addition, even if the exchanger does freeze and the flow of working fluid is stopped, the adjustment of the temperature at (506) can rapidly thaw the exchanger and restore the fluid flow.
Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement, which is calculated to achieve the same purpose, may be substituted for the specific embodiment shown. This application is intended to cover any adaptations or variations of the present invention. Therefore, it is manifestly intended that this invention be limited only by the claims and the equivalents thereof.

Claims

1. A heat exchange system comprising:

a first container adapted to hold a first fluid;

a second container adapted to hold a second fluid, the second container thermally coupled to the first container such thermal energy transfer between the first and second container occurs; and

at least one heater embedded with the first and second container.

2. The heat exchange system of claim 1, wherein the at least one heater is one of a solid plate heater, a rope heater, a wire heater and an immersion heater.

3. The heat exchange system of claim 1, wherein the first container is a thermally conductive tube having one or more coils and the second container is also a thermally conductive tube having one or more coils.

4. The heat exchange system of claim 3, wherein the at least one heater is at least one wire heater positioned adjacent the one or more coils of the first and second containers.

5. The heat exchange system of claim 3, wherein the at least one heater is at least one wire heater wrapped around the one or more coils.

6. The heat exchange system of claim 3, further comprising:

conductive material encasing the one or more coils of the first and second containers and the wire heater.

7. The heat exchange system of claim 6, further comprising:

insulation material encasing the conductive material.

8. A method of manufacturing a heat exchanger, the method comprising:

forming a first thermal container adapted to contain a first liquid;

forming a second thermal container adapted to contain a second liquid, the second thermal container being thermally coupled to the first thermal container; and

embedding at least one heater with the first and second thermal containers.

9. The method of claim 8, wherein forming the first thermal container further comprises:

forming one or more coils with the first thermal container; and wherein forming the second thermal container further comprises;

forming one of more coils with the first thermal container, wherein the one or more coils of the first and second thermal containers are in thermal contact with each other.

10. The method of claim 9, wherein embedding the at least one heater with the first and second thermal containers further comprises:

placing the at least one heater with the one or more coils of the first and second thermal containers.

11. The method of claim 9, further comprising:

forming a layer of conductive material around the one or more coils of the first and second thermal conductors and the heater.

12. A method of operating a heat exchange, the method comprising:

generating a flow of a first fluid in a first container;

generating a flow of a second fluid in a second container, wherein the second container is thermally coupled to the first container; and

adjusting the thermal energy in the first and second fluids with at least one heater that is integrated with the first and second container.

13. The method of claim 12, further comprising:

thawing frozen first and second fluids in the first and second containers in a relatively rapid fashion with the at least one heater.

14. A heat exchange system comprising:

a first means for containing a first fluid;

a second means for containing a second fluid, the first and second means being in thermal contact with each other; and

a means for heating the first and second fluids with a heater embedded with the first and second means for containing the first and second fluid.

15. The heat exchange system of claim 14, further comprising:

a means for enhancing thermal transfer between the first fluid, second fluid and the means for heating.

16. The heat exchange system of claim 14, further comprising:

a means for insulting the heat exchange system from the environment it is located in.