GB2308181A

GB2308181A - Heat exchange elements

Info

Publication number: GB2308181A
Application number: GB9625689A
Authority: GB
Inventors: Martin Johns
Original assignee: LLOYD PETA
Current assignee: LLOYD PETA
Priority date: 1995-12-12
Filing date: 1996-12-11
Publication date: 1997-06-18
Anticipated expiration: 2016-12-11
Also published as: GB9525351D0; GB9625689D0; GB2308181B

Description

DESCRIPTION HEAT EXCHAN ELStiENrS This invention relates to heat exchanger plates for gas/solid valve regenerative application and to their assembly in the floor constructions of buildings to construct aerdecks. The plates are of corrugated or folded configuration, forming a multitude of separated longitudinal channels which afford direct contact of a heat transfer medium contained within them with the floor slab, and indirect contact with any contiguous floor screed laid above the plate.

Aerdecks are proposals intended to be integrally part of the building and of its thermal conditioning. For aerdecks the transport fluid is air which is made to pass over the fabric of the building, for example the concrete of the floors. Other massive constructional elements may alternatively be employed, eg. walls.

Previous designs of aerdeck systems have envisaged interconnected air pathways across the area of a floor slab, formed either of linked matrix sheet components or of individual domes and connectors. For these the air in the system is in direct contact with the supporting floor slab. The elements forming the air pathways may also be used as permanent shuttering for a floor screed, which then performs as an indirect contact1 second regenerative heat sink. The fluid is valved and is made to periodically flow through the air system, rejecting thermal energy to or retrieving it from contiguous or thermally connected sinks.

It is the aim of the current invention to improve the heat transfer-pressure loss performance of aerdecks through the configuration of the element used, while presenting a simple, cost effective means of its realisation. This plate form of element may also be of application to fluid/solid single plate valve regenerative heat exchangers in general, and to recuperative exchangers, both using alternative fluids.

Figure 1 shows a form of plate of equal trapezoidal profiled configuration.

Figure 2 shows a form of plate of equal trapezoidal contoured configuration.

Figure 3 shows a form of indentingimoulding of asymmetrical, aerofoil configuration.

Figure 4 shows a profiled plate assembled in an aerdeck application.

Figure 5 shows a contoured plate assembled in an aerodeck application.

The present invention is for aerdeck applications, where it is proposed that the plates that form the air paths be of a form that defines linear isolated channels, with no interconnection. These may be of any geometry, typically formed by vacuum, folding or rolling. The figures given utilise an equal trapezoidal configuration for example only. This may be changed to other preferred geometries, to increase the air channel volume and the air contact area, and to decrease the downstand rib section, or to suit other criteria.

At its simplest, the cross-section of this configuration of plate may be characterised as shown in fig. 1, and is constant at all points along the length of the profile.

The configuration may be developed by one or more surfaces of the plate being indented, as characterised in fig. 2. Such indentations may be continuous or intermittent, have surfaces transverse or at an angle to the direction of air flow, and be of various extent toward or away from the central plane of the plate.

This may be further developed by the incorporation of indentations of an asymmetrical form with dissimilar leading and trailing surfaces configurations and a point of inflexion, as characterised in fig. 3. These forms are termed aerofoil configurations and when used in directed fluid flow, as indicated F fig. 3, promote separation of the boundary layer. These configurations and flow arrangements produce aerofoil effects, where such effects are realised not at the fixed solid element, but in the fluid stream.

Plates with constant cross section are referred to as 'profiled'. Plates with indentations or mouldings of any form are referred to as 'contoured'.

Figure 4 shows a first embodiment of the invention in the form of a regular trapezoidal profiled plate as fig. 1, in an aerdeck construction (P), with a floor screed over (S1), where this floor screed is optional. When such a profiled sheet is in contact with a plane or approximately plane surface (S2) a plurality of continuous, unconnected channels (A) are formed which may be occupied by the fluid of the system, and within which it may be made to flow. The channels present regenerative heat transfer boundaries. Flow resistance and pressure loss is low.

Figure 5 shows a second embodiment of the invention in the form of a regular trapezoidal contoured plate as fig. 2, in an aerdeck construction (P), with an optional floor screed (S1) over. Similar to embodiment 1, when such a contoured sheet is in contact with a plane or approximately plane surface (S2) a plurality of continuous, unconnected channels (A) are formed which may be occupied by the fluid of the system, and within which it may be made to flow. For a heat transfer fluid moving between the sheet and the surface, the boundary formed by the contoured sheet shown presents indentations into the channel (ridge indentations shown as example), intruding intermittently into the enclosed spaces, and affecting flow type and pressure. The indentations may be shaped and spaced to promote disruption of the boundary layer due to circulation or turbulence of the fluid.Fluid mixing is induced, reducing the fluid temperature profile and increasing the rate of any convective heat transfer. The configuration of plate is referred to as an aerodeck form and the construction as an aerodeck system.

This may be further developed by asymmetrically moulding the indentations to form aerofoil configurations, as detailed above and shown in fig. 3, and co-orientating the indentation and fluid flow directions.

The indentations will enhance convective heat transfer at the regenerative heat transfer boundaries of the passages. This can be optimised with respect to consequential increase of pressure loss by the selection of indentation geometry and configuration with regard to the properties of the heat transfer fluid.

The configuration of plates of the invention may be manufactured in a number of materials by vacuum forming, and by traditional rolling and pressing methods.

Claims

CWMS

1 / A heat exchanger plate for gas/solid valve regenerative application in the aerdecks of buildings, of corrugated or folded configuration, forming a multitude of separated longitudinal channels affording direct contact of a heat transfer medium contained within them with the floor slab, and indirect contact with any contiguous floor screed laid above the plate.

2 / A plate according to Claim 1 In which some percentage of the area of the surfaces are deformed or moulded but not punched through, to produce continuous or isolated indentations of the channel surface of one or various symmetrical or irregular geometries, of various surface area extents and toward or away from the central plane of the plate, producing a contoured plate which modifies the flow pattern of a heat transfer fluid when it is flowing through the channels so formed.

3 I A plate according to Claim 2 in which one or more of the deformations or mouldings include a surface asymmetrical or aerofoil in form which is used with some component of the principal direction of fluid flow in the direction of orientation of the aerofoil indentations.

4 / Jointing, blanking, and manifold components to join to the elements or components of the invention.

5 / A heat transfer element or component substantially as described herein or as shown in Figures 1-5 of the accompanying drawings.

3 / A plate according to Claim 2 in which one or more of the deformations or mouldings include a surface asymmetrical or aerofoil in form which is used with some component of the direction of fluid flow in the direction of orientation of the aerofoil indentations.

5 I A heat transfer element or component substantially as described herein or as shown in Figures 1-5 of the accompanying drawings.

Amendments to the claims have been filed as follows II A heat exchanger plate for fluid/solid valve regenerator application in the aerdecks of buildings or similar situations, of corrugated or folded configuration,which when located on a surface form a multitude of separated channels affording direct contact of a heat transfer medium contained within them with a primary heat sink eg. floor slab, and indirect contact with any contiguous secondary heat sink eg. floor screed laid above the plate, and which by the physical enclosure of the channel, constrain the flow of any fluid within it to principally the longitudinal axis of the corrugation.

2 / A plate according to Claim 1 in which some percentage of the area of the surfaces are formed, deformed or moulded but not punched through, to produce continuous or isolated indentations of the channel surface of one or various symmetrical or irregular geometries, of various surface area extents and toward or away from the central plane of the plate, producing a contoured plate which modifies the flow pattern of a heat transfer fluid when it is flowing through the channels so formed, imparting fluid motion contrary to the longitudinal axis of these channels.