RU2584081C1 - Micro channel heat exchanger - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: invention relates to heat exchange equipment and can be used in microchannel heat exchangers. Micro channel heat exchanger consists of a rigid body comprising a heat exchange matrix, formed from thin smooth heat-conducting plates of identical structure soldered with each other, branch pipes for inlet and outlet of hot and cold heat carriers, heat exchange matrix is attached to heat carrier inlet and outlet plates with holes providing delivery of each of heat carriers to collector channels of hot and cold heat carriers, located opposite each other, then supply of heat carrier to main channels of hot and cold heat carriers, wherein adjacent plates of heat exchange matrix are differently oriented to feed and discharge heat carrier flow from different sides, so that smooth heat-conducting plates are soldered together by a thin wire to make micro channels.

EFFECT: technical result is increase in efficiency of microchannel heat exchangers.

2 cl, 3 dwg

Description

The proposed technical solution relates to the field of heat transfer technology and is aimed at improving the efficiency of microchannel heat exchangers.

A number of devices are known where various existing methods for increasing efficiency are described, for example, RU 2010104252, application for an invention: “Heat exchange system with a heat exchange device, as well as a method for manufacturing a heat exchange system”, 08/20/2011, RU 107582 “Microchannel heat exchanger with nanorelief”.

Closest to the proposed invention and adopted as a prototype is the device presented in the patent: US 4,516,632 (Micro Channel cross flow fluid heat exchanger and method for its fabrication)), 1982.

The microchannel heat exchanger presented in US Pat. No. 4,516,632 consists of a set of thin metal plates brazed together, having a plurality of parallel slots that form channels for the movement of coolant, include inlet and outlet pipes that supply coolant to the rectangular openings of the collector to form two sets of channels for the heat carrier, with a transverse flow, where each of these slit sheets includes a set of four rectangular collector holes, forming internal manifolds for fluid flow, located opposite each other.

Such installations have the following disadvantages: consecutive channels in the set are rotated ninety degrees with respect to each other so as to form two sets of channels providing a cross-flow, rather than counter-current, movement pattern. The plates are not fixed relative to each other along the paths of the coolant, so the design may not be rigid enough. In addition, these channels have a large length in the direction of the coolant.

The traditional way to increase the efficiency of heat transfer in microchannel heat exchangers is also to reduce the size of the heat exchange channels with an increase in their number and create a microrelief on the surface of the channels. This increases the consumption of materials and the cost of heat exchangers.

The technical problem solved by the proposed device is to increase the efficiency of microchannel heat exchangers, reduce the consumption of expensive electric energy for pumping coolant, increase the life of pumping equipment, reduce material consumption, reduce the cost of heat exchangers and operating costs.

The technical effect, which allows to solve the technical problem, is to increase efficiency by organizing a predominantly countercurrent flow diagram for the relative movement of heat carriers, reducing the hydraulic diameter and reducing the hydraulic resistance of the flow part by reducing the length of the main channels of microchannel heat exchangers.

The problem is solved in that the well-known microchannel heat exchanger, consisting of a rigid body containing a heat transfer matrix formed of thin heat-conducting plates welded together of the same design, forming channels, pipes for supplying and discharging coolants, while the heat-transfer matrix is fixed to located at the input and according to the invention is equipped with two types of channels of hot and cold coolants: collector, located at opposite to each other, and the main channels, while the plates of adjacent layers of the heat transfer matrix are differently oriented relative to each other.

In addition, thin heat-conducting plates are soldered together using a thin wire, forming microchannels, and the length of the main channels is comparable with their height.

Thus, in the microchannel heat exchanger, a predominantly countercurrent scheme of the relative motion of the coolants is organized and the hydraulic diameter of the channels is reduced, which, with a small hydraulic resistance of the flow part, ensures high compactness of the heat exchanger and high value of the heat transfer coefficient, which results in high thermal efficiency of the apparatus compared to existing microchannel heat exchangers.

In FIG. 1 shows a microchannel heat exchanger.

In FIG. 2 shows the assembly of plates of a heat exchange matrix.

In FIG. 3 shows a diagram of the movement of coolants along the plates of a heat transfer matrix.

The microchannel heat exchanger (Fig. 1), which belongs to the class of recuperative heat exchangers, consists of a rigid casing 1 containing a heat exchange matrix 2 (Fig. 2) formed of thin smooth heat-conducting plates 3 (Fig. 3) of the same design welded together, pipes for supplying 4, 5 and removal of hot and cold coolants 6, 7, the heat exchange matrix is attached to the plates 8 located at the inlet and outlet of the coolant, with openings 9 that supply each of the coolants to the collector channels of grief bringing 10 and cold 11 coolants, located opposite to each other, then supplying the coolant to the main channels of hot 12 and cold 13 coolants, while adjacent plates with microchannels of the heat transfer matrix are differently oriented relative to each other, which makes it possible to supply and remove the coolant flow with of different sides, organizing a predominantly countercurrent flow diagram of coolants, more efficient than a cross-flow diagram, while smooth heat-conducting plates are soldered between by itself using a thin wire 14, forming microchannels with a distance between the plates from 100 to 2000 microns.

The installation works as follows (Fig. 1 and 3).

The hot heat carrier is supplied to the pipe 4 and through the hole 9 in the plate 8 located at the inlet of the hot heat transfer medium enters the space above the heat transfer matrix - to the collector channel of the hot heat transfer medium 10. Then it enters the main channels 12 open from above (even) formed by the plates of the heat transfer matrix 3 and soldered wire 14.

The cold heat carrier is supplied to the pipe 5 and enters the space under the heat exchange matrix - to the collector channel of the cold heat carrier 11. Then it enters the main channels 13, which are open from the bottom, formed by the plates of the heat exchange matrix 3 and the wire 14 soldered to them.

Through the walls of the channels, heat is transferred from the hot coolant to the cold, moving along adjacent channels. The zone of the most intense heat exchange is organized in such a way that it provides countercurrent movement of heat carriers in microchannels.

Cooled hot heat carrier is removed from the heat transfer matrix and is removed from the heat exchanger through the pipe 6.

The heated coolant is removed from the heat transfer matrix and is removed from the heat exchanger through the pipe 7.

The soldered wire plays the following role:

- organizes the walls of microchannels with a small hydraulic diameter, which leads to a significant increase in heat transfer;

- provides countercurrent movement of coolants in the zone of the most efficient heat transfer;

- plays the role of surface finning, which leads to an increase in heat transfer;

- provides structural rigidity with a small plate thickness.

The thickness of the wire and the step of its location on the surface of the plates determine the hydraulic diameter of the microchannels, the surface area of the fins, and thus the transmitted heat flux, and the hydraulic resistance in the system.

The dimensions of the plates, the distance between them, the distance between the wire forming the channels, are calculated and optimized by a special technique.

The proposed heat exchanger differs from existing microchannel heat exchangers in that it provides primarily a countercurrent flow diagram of the heat carriers due to the possibility of supplying and removing the heat carrier flow from different sides, which is more efficient than the cross-current scheme, and also due to the short length channels, low hydraulic resistance of the flow part is achieved, and due to the high compactness and high values of the heat transfer coefficient, high heat vehicle efficiency. Thin heat-conducting plates of the heat exchanger are soldered together using a thin wire, forming microchannels, which ensures rigidity and a fixed distance between the plates from 100 to 2000 microns.

The proposed heat exchanger also provides a reduction in the consumption of expensive electric energy for pumping coolant, an increase in the life of the pumping equipment, a decrease in material consumption, a decrease in the cost of heat exchangers and operating costs.

Claims (2)

1. Microchannel heat exchanger, consisting of a rigid casing containing a heat transfer matrix formed of thin heat-conducting plates welded together of the same design, forming channels, pipes for supplying and removing heat carriers, the heat transfer matrix is fixed to plates with holes located at the input and output of the heat carrier, characterized in the fact that it is equipped with two types of channels of hot and cold coolants: collector, located opposite each other, and the main channels, when the volume of the plate with microchannels of adjacent layers of the heat transfer matrix are differently oriented relative to each other. 2. The microchannel heat exchanger according to claim 1, characterized in that the thin heat-conducting plates are soldered together using a thin wire, forming microchannels, and the length of the main channels is comparable with their height.

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