Microchannel Heat Exchangers and Reactors

Abstract

A method of making a core of, or a micro-channel heat exchanger includes making constructs from wire and sheet material. The constructs are then stacked together according to the desired orientation of the channels for the core. The stacked constructs are then bonded together to form the core.

Description

PRIORITY CLAIM[0001]This application claims priority U.S. provisional application No. 61 / 474,698 filed on Apr. 12, 2011 (attorney docket no. 100842.4).[0002]The invention was made with Government support under DE-FG02-07ER84875 awarded by the Department of Energy (DOE). The Government has certain rights in the invention.FIELD OF THE INVENTION[0003]The present invention relates to micro-channel heat exchangers; more particularly, this invention relates to processes for making micro-channel heat exchangers.BACKGROUND OF THE INVENTION[0004]Microchannel based heat exchangers hold great promise for reducing heat exchanger weights and volumes. Since the heat transfer coefficient increases inversely as the channel diameter, the amount of surface area needed to transfer a given amount of heat decreases directly with the channel diameter. This opens up the possibility of creating extremely compact heat exchangers, of reduced weight, using very small channels. As the size of the channels and ...

AI Technical Summary

Benefits of technology

[0028]According to another aspect of the invention a manufacturing method according to the invention uses low-cost material and techniques for assembly of constructs, thereby significantly reducing the manufacturing cost and promoting widespread utilization of microchannel heat exchangers. The following applications refer to conventional microchannel heat exchanger uses, however, it is contemplated that the inventive cores and manufacturing methods are capable of addressing many other applications where conventional heat exchangers are being used because of the higher manufacturing cost of current microchannel heat exchangers.

Problems solved by technology

However, current microchannel fabrication costs cannot be easily justified for low value heat exchange applications.

In particular, space and weight limited transportation applications could greatly benefit from a low cost microchannel heat exchanger fabrication technique.

Semiconductor Cooling: There are increasing demands for liquid cooling systems for high heat flux electronics, where space limitations are significant.

A microchannel evaporator design, related to refrigerant flow maldistribution and the ability of the evaporator coil to effectively shed condensate, has been a technical challenge.

Micromachining, while capable of producing efficient and low volume microchannel heat exchangers, the delicate nature of the tools and the high accuracy and precision required make microchannel heat exchangers in this manner is expensive.

However, this method is relatively slow, which drives up fabrication costs.

This drives up fabrication costs.

In serial processes, the part is machined in a step by step approach, which typically results in low material removal rates and low throughput.

This is justified for specialized high volume applications, but is too costly for many heat exchanger applications of interest.

Unfortunately, the process is very slow, and requires many hours.

This is not a viable technique for low cost heat exchanger applications.

Given the complexity of the approach and the slow processing speed, this technique would also not be viable for low value applications.

However, LIGA has failed to become widely accepted because of the difficulty in making masks and the high cost.

While this technique can produce useful heat exchangers and reactor cores, costs are higher than desired.

It has been indicated that each lamination would cost approximately $500 per pound, which is a high cost for low value heat exchanger application.

However, costs of these units are high because of the expense to form the many microchannels using conventional micromachining or etch methods.

This adds time and cost to the fabrication process, and makes these techniques too expensive for low value heat exchanger applications.

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