GB2481225A

GB2481225A - Heat exchanger particularly for use in the ventilation of buildings

Info

Publication number: GB2481225A
Application number: GB1010047.7A
Authority: GB
Inventors: Steven Thomas Barson
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-06-16
Filing date: 2010-06-16
Publication date: 2011-12-21
Also published as: GB201010047D0

Abstract

The heat exchanger comprises a pipe 2 having an outer wall, the pipe being divided into a plurality of elongate sections by one or more dividing walls. The dividing walls permit the transfer of heat between fluids flowing in the elongate sections, and the heat exchanger permits fluid to flow in a first direction along at least one of the elongate sections while subsequently permitting fluid to flow in a second, opposing direction along at least one of the other elongate sections. The heat exchanger may include end caps 1,3 on either end of the pipe, the end caps providing both inlets 'a','c' and outlets 'b','d' for the fluids. Portions of the outer wall may be removed to provide additional fluid inlets and/or outlets. The heat exchanger may be used as a skirting board made from extruded aluminium, high-density ceramics or PVC as part of a ventilation system of a building, the fluids being stale and fresh air, or any other gas or liquid.

Description

Heat exchanger This invention relates to the construction of a heat exchanger through which air passes for the purposes of ventilation.

Many buildings rely on ventilation systems to ensure a supply of fresh air. To minimise the energy lost by replacing warmed indoor air with cool outside air, many systems pass the incoming and outgoing air through a heat exchanger. The outgoing air gives up some of its heat to the incoming air. This current type of heat exchanger generally relies on the flows of air being separated in layers and crossing each other at a predominantly 90 degree angle, this method is illustrated in patent EP2169339A1.

The major drawback with this method is that physical constraints of construction mean that the air can only pass through the heat exchanger for a small distance -for air to go through 1 meter of heat exchanger, the heat exchanger would have to be an inhibitive 1 meter x 1 meter in dimension -therefore the amount of heat reclamation possible is limited.

A second constraint with the current method is that the heat exchanger is difficult and expensive to fabricate.

To overcome these problems this invention uses a construction which allows the air to pass through the heat exchanger for longer distances, and involves a relatively simple and inexpensive method of construction.

An example of the invention will now be described by referring to the accompanying drawings.

Figure shows the perspective view of a pipe with a square honeycomb type structure within. The honeycomb is continuous so air entering one cell will exit through the corresponding connected cell at the other end. For simplicity this section will be referred to as the Pipe'. In these diagrams the Pipe is shown as being straight although it is recognised that it could be bent to form a curve or mitred and joined to form other shapes and angles.

Figure II shows the end view of the Pipe in figure I Figures III and IV show the end views of Pipes with examples of some other suitable internal structures Figure V shows a perspective view of a cap which fits on the end of the Pipe. For simplicity this component will be referred to as the End Cap. The End Cap has at least two ducts (1). Ventilation tubing will usually be fitted over the ends of the ducts so stale air from a room and fresh air from outdoors will be blown and moved into and out of the heat exchanger. The internal structure of the End Cap is such that a flow of air identified as (a) entering the End Cap via one duct can only exit through the alternate layers in direction (c) Figure VI shows an example of the assembled heat exchanger. The assembled heat exchanger consists of The Pipe as shown in figure I, with an End Cap (shown in figure V) on each end.

Figure VII shows the perspective view of a section which could connect two pieces of Pipe to extend the length of the heat exchanger assembly.

Figure VIII shows an example of an extended heat exchanger assembly. In this instance three sections the Pipe have been joined.

Figure X shows an end view cross section of an end cap and demonstrates how the internal structure divides and controls the flow of air.

Figure X shows another example of End Cap where the air flows are directed at 90 degrees to each other.

Figure XI shows a cross section through points y-y of the End Cap in figure X. Figure XII shows the end view of the End Cap in figure X Figure XIII shows the assembled heat exchanger as it could be used in a domestic situation.

Figure XIV shows a section of Pipe with slots cut into the divided cells. The end of the Pipe has been closed to prevent the passage of air (1). Air flow identified as (4) moves through the Pipe and exits at slots (2). At the same time air identified as (5) enters slots (3) and passes in the opposite direction to air flow 4.

Figure XV shows a variation on Figure XIV. In this example slots (2) are cut into the cells carrying one direction of air flow (4), and an end cap has slots (3) to allow the passage of air in the other direction (5).

This invention will now be described using Figure I, V and VI.

An End Cap (figure V) fits over each end of the Pipe (figure I) to create the structure shown in figure VI. The internal dividing structure of the End Caps (5 in figure V) align with the dividing walls between the rows of cells within the Pipe (3 and 4 in figure 1) and form a preferably airtight seal.

In figure VI, when air enters through duct (a) in end cap (1), the dividing sections of the cap direct the air down alternate rows of cells of the Pipe (3 in figure 1). The air exits at the other end of The Pipe and is directed by the dividing structure in End Cap (3) and exits at (b) At the same time, air enters at duct (c) in figure VI, is directed by the internal dividing structure of End Cap 3 and directed down the other alternate rows of cells in the Pipe (shown as 4 in figure I). This air exits the pipe and is directed by the internal dividing structure of End Cap (1) and exits at duct (d).

The warm room air passing down the rows of cells 3 in figure I, gives up its heat to the cell walls and warms the cool air passing down the alternate rows of cells (4 in figure I).

Figure XIII shows the assembled heat exchanger (1) as it could be used in a domestic situation. Fresh outdoor air is drawn in through duct (2) by means of a fan or fans, enters the heat exchanger (1) and exits via duct (3) into the room. Stale air is drawn from the room via duct (4), passes through the heat exchanger and exits to the outdoors via duct (5). As the two air flows pass one another in the heat exchanger, the heat of the stale air is given up to the fresh air.

Figure VII shows a section which joins two Pipes together, this will now be known as The Connecting Section. The ends of two Pipes fit into the Connecting Section. The internal dividing structure aligns with the dividing walls within the Pipes to form a preferably air tight seal. As an example, air (a) exiting the Pipe will enter the Connecting Section, pass around it, and exit at (b). Air (c) will enter the Connecting Section and exit at (d). . In this manner the air flows may continue their passage for a longer distance, therefore recovering more of the potentially lost heat, and will still not mix with one another. In this example the Connecting Section directs the air through a 180 degree bend, but other angles can be achieved by the same process, in Figure XVI a 90 degree bend is illustrated (6).

Figure XVI shows an example of the heat exchanger Pipe described in XIV being utilised as a skirting board. Fresh air is drawn in from the outside down duct 2. it enters the End Cap (1), is directed along alternate sections in the Pipe (7), and exits through slots (4). At the same time stale air from the room is drawn through slots (3) and travels along the other alternate slots in pipe (7). The End Cap (1) then directs the stale air to exit though duct (5).

The shape and sizes of cells shown in the drawings are demonstrative.

For illustrative purposes, the ducts in Figure VI are shown exiting the heat exchanger at an angle of predominantly 90 degrees to the direction of the Pipe. It is recognised that the ducts could exit at other directions and angles. Another suitable configuration is demonstrated in figures X, XI and XII, where the dividing sections in the End Cap are designed so that one flow of air could enter or exit in a direction predominantly in the same direction as the flow through the heat exchanger, whilst the other exits at a right angle.

The ducts on the end of the caps are shown as being circular. There is of course no reason why they could not be rectangular or some other suitable shape.

All the examples described show the direction of air moving in opposite directions in each adjoining section. There could be other configurations, such as two cells carrying air in the same direction next to two cells carrying air in the other direction, the heat recovery of such a configuration however would not be as efficient.

The heat exchanger assembly may if desired have a fan or fans fitted to control the flow of air.

It has been found that the pipe shown in figure I is easily produced by means of extrusion, it could however be fabricated if required. Due to their ease to extrude, price and poor insulating properties, PVC and high density ceramic are good materials to use when making the pipe. Other materials such as aluminium would also be suitable to use.

Although the heat exchanger has been described as being used for air, it is recognised that it would be equally suitable for use with other gasses or liquids.

For illustrative purposes, drawings VI, VIII and XIII show the air entering and leaving the ducts on the End Caps on the same side of the heat exchanger. It is recognised that if the construction of the end caps was identical the air would exit on the opposite diagonal side of the heat exchanger to which it entered.

Claims

Claims 1 A pipe comprising several divided sections through which air is directed to move in opposite directions providing a heat exchanger which transfers heat through the dividing walls of the sections from one direction of air flow to the other.
2 A heat exchanger as described in claim 1 which has an end cap fitted to one end of the pipe which provides both an inlet and outlet to keep the flows of air separate and direct them into and out of the divided sections of the pipe.
3 A heat exchanger as described in claim 1 with an end cap fitted to each end of the pipe each of which provides both an inlet and outlet to keep the flows of air separate and direct them into and out of the divided sections of the pipe.
4 A heat exchanger as described in claim 1 where parts of the external pipe wall are removed to expose the sections carrying air travelling in one direction thereby creating a point of entry or exit.
A heat exchanger as described in claim 1 where parts of the external pipe wall are removed to expose the sections carrying air travelling in one direction thereby creating a point of entry, and in another area parts of the external wall are removed from the other sections to create a path of exit for air travelling in the other direction.
6 A heat exchanger as described in claims 4 or 5 which has an end cap fitted to one end of the pipc which providcs both an inlet and outict to kccp the flows of air separate and direct them into and out of the divided sections of the pipe.
7 A heat exchanger consisting of a pipe and end cap as described in claim 2 where sections of the outer wall of the pipe are removed to allow the exit or entry of one direction of air flow.
8 A heat exchanger as described in claim 7 where sections of the outer wall of the pipe are removed to allow the exit of air in one area and the entry of air in another area.
9 A heat exchanger as described in claim 7 where one direction of air flow can pass through the removed sections of the outer wall of the pipe and the other direction of air can pass through the unblocked end of the pipe.A heat exchanger as described in any of the above claims where the pipe takes the form of a skirting board.