Indirect heat exchanger having circuit tubes with varying dimensions

Patent metadata

Field	Value
Publication number	US-11644245-B2
Application number	US-202016858275-A
Country	US
Kind code	B2
Filing date	Apr 24, 2020
Priority date	Oct 12, 2016
Publication date	May 9, 2023
Grant date	May 9, 2023

Abstract

An improved indirect heat exchanger including a plurality of coil circuits, with each coil circuit comprised of an indirect heat exchange section tube run or plate. Each tube run or plate has at least one change in its geometric shape or may have a progressive change in its geometric shape proceeding from the inlet to the outlet of the circuit. The change in geometric shape along the circuit length allows simultaneously balancing of the external airflow, internal heat transfer coefficients, internal fluid side pressure drop, cross sectional area and heat transfer surface area to optimize heat transfer.

First claim

What is claimed is:

1. An indirect heat exchanger comprising:
a plurality of circuit tubes including a first circuit tube and a second circuit tube;
inlet and outlet headers connected to the circuit tubes;
an evaporative fluid supply configured to distribute evaporative fluid onto the circuit tubes;
a sump configured to collect evaporative fluid from the circuit tubes;
a pump configured to pump evaporative fluid from the sump to the evaporative fluid supply;
a fan and a motor operable to cause air to move over the circuit tubes;
each circuit tube extending in a series of run lengths and return bends, each circuit tube having vertical spacings between the run lengths of the circuit tube;
the run lengths of each circuit tube having a decreasing horizontal cross sectional dimension and an increasing vertical cross sectional dimension as the circuit tube extends from adjacent the inlet header to adjacent the outlet header;
inlet run lengths of the first and second circuit tube that are adjacent the inlet header, the inlet run lengths adjacent the inlet header having a first horizontal distance therebetween;
outlet run lengths of the first and second circuit tube that are adjacent the outlet header, the outlet run lengths adjacent the outlet header having a second horizontal distance therebetween;
wherein the first horizontal distance is smaller than the second horizontal distance;
wherein the first circuit tube and the second circuit tube are vertically offset from one another;
wherein the run lengths of the first circuit tube include a first plurality of intermediate run lengths intermediate the inlet and outlet run lengths of the first circuit tube along the first circuit tube;
wherein the run lengths of the second circuit tube include a second plurality of intermediate run lengths intermediate the inlet and outlet run lengths of the second circuit tube along the second circuit tube;
wherein the vertical spacings of the first circuit tube include first intermediate vertical spacings between the first plurality of intermediate run lengths and the vertical spacings of the second circuit tube include second intermediate vertical spacings between the second plurality of intermediate run lengths;
wherein the first plurality of intermediate run lengths of the first circuit tube are horizontally aligned with the second intermediate vertical spacings of the second circuit tube and the second plurality of intermediate run lengths of the second circuit tube are horizontally aligned with the first intermediate vertical spacings of the first circuit tube;
wherein the first plurality of intermediate run lengths have decreasing vertical distances from adjacent ones of the second plurality of intermediate run lengths as the first circuit tube extends from adjacent the inlet header to adjacent the outlet header; and
wherein the second plurality of intermediate run lengths have decreasing vertical distances from adjacent ones of the first plurality of intermediate run lengths as the second circuit tube extends from adjacent the inlet header to adjacent the outlet header.

2. The indirect heat exchanger of claim 1 wherein the vertical spacings of each circuit tube between the run lengths of the circuit tube progressively narrow as the circuit tube extends from adjacent the inlet header to adjacent the outlet header.

3. The indirect heat exchanger of claim 1 wherein each circuit tube run length is of a uniform horizontal cross sectional dimension and a uniform vertical cross sectional dimension for the entire length of the circuit tube run length.

4. The indirect heat exchanger of claim 1 wherein the circuit tubes each have an inner surface that defines a fluid flow path and an outer surface opposite the inner surface, the inner surface and the outer surface having matching cross-sectional shapes throughout the circuit tube.

5. The indirect heat exchanger of claim 1 wherein the run lengths of each circuit tube have the same internal surface area and the same external surface area.

6. The indirect heat exchanger of claim 1 wherein the inlet run lengths of the first and second circuit tubes that are adjacent the inlet header each have a first ratio of the vertical cross sectional dimension of the run length to the horizontal cross sectional dimension of the run length;
wherein the outlet run lengths of the first and second circuit tubes that are adjacent the outlet header each have a second ratio of the vertical cross sectional dimension of the run length to the horizontal cross sectional dimension of the run length; and
wherein the second ratio is larger than the first ratio.

7. The indirect heat exchanger of claim 6 wherein the first ratio is in the range of one to two, and the second ratio is greater than the first ratio but less than six.

8. The indirect heat exchanger of claim 1 wherein the run lengths of each circuit tube include run lengths having a non-circular cross section; and
wherein the run lengths of each circuit tube have a uniform circumference.

9. The indirect heat exchanger of claim 1 wherein the inlet run lengths of the first and second circuit tube that are adjacent the inlet header each include a cylindrical outer surface extending from adjacent the inlet header to adjacent one of the return bends of the circuit tube.

10. The indirect heat exchanger of claim 1 wherein each circuit tube return bend is circular in cross section.

11. The indirect heat exchanger of claim 1 wherein each circuit tube includes galvanized steel, stainless steel, aluminum, and/or copper.

12. The indirect heat exchanger of claim 1 wherein each circuit tube has a unitary, one-piece construction.

13. The indirect heat exchanger of claim 1 wherein the run lengths each run lengths of the first and second circuit tubes include cylindrical run lengths having a circular cross-section, the cylindrical run lengths intermediate the inlet run lengths and the inlet header along the first and second circuit tubes.

14. An indirect heat exchanger comprising:
a plurality of circuit tubes including a first circuit tube and a second circuit tube;
inlet and outlet headers connected to the circuit tubes;
an evaporative fluid supply configured to distribute evaporative fluid onto the circuit tubes;
a sump configured to collect evaporative fluid from the circuit tubes;
a pump configured to pump evaporative fluid from the sump to the evaporative fluid supply;
a fan and a motor operable to generate airflow relative to the circuit tubes;
each circuit tube extending in a series of run lengths and return bends, each circuit tube having vertical spacings between the run lengths of the circuit tube;
inlet run lengths of the first and second circuit tube that are adjacent the inlet header;
outlet run lengths of the first and second circuit tube that are adjacent the outlet header;
wherein the first circuit tube and the second circuit tube are vertically offset from one another;
wherein the run lengths of the first circuit tube include a first plurality of intermediate run lengths intermediate the inlet and outlet run lengths of the first circuit tube along the first circuit tube;
wherein the first plurality of intermediate run lengths have a decreasing horizontal cross sectional dimension and an increasing vertical cross sectional dimension as the first circuit tube extends from the inlet run length toward the outlet run length thereof;
wherein the run lengths of the second circuit tube include a second plurality of intermediate run lengths intermediate the inlet and outlet run lengths of the second circuit tube along the second circuit tube;
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Assignees

• Baltimore Aircoil Co Inc

Inventors

• Beaver Andrew
• Aaron David Andrew
• Rousselet Yohann Lilian

Classifications

• F28D1/047

  the conduits being bent, e.g. in a serpentine or zig-zag · CPC title

• F28F2210/08

  Assemblies of conduits having different features · CPC title

• F28F9/02

  Header boxes; End plates · CPC title

• F28D1/0477 Primary

  the conduits being bent in a serpentine or zig-zag · CPC title

• F28F21/084

  from aluminium or aluminium alloys · CPC title