GB2447975A

GB2447975A - Flue liner having thermal energy recovery apparatus

Info

Publication number: GB2447975A
Application number: GB0706277A
Authority: GB
Inventors: Nicholas Ralph Allen
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-03-30
Filing date: 2007-03-30
Publication date: 2008-10-01
Also published as: GB0706277D0

Abstract

A twin walled flue liner for use in non-industrial chimneys. The flue liner 1 comprises an inner wall 3 and an outer wall 5, with a thermal energy recovery apparatus 6 located between the walls. An insulating layer 4 may at least partly surround the thermal energy recovery apparatus. The thermal energy recovery apparatus may be a heat exchanger that is integral with one or both of the walls of the liner and can be connected to a domestic heating system. Preferably, the heat exchanger is one of a coil, a mesh or a fins arrangement. The thermal energy recovery apparatus may comprise inlet and outlet ports 6a, 6b extending through the outer wall for passage of a heat transfer fluid such as water. Preferably, the liner is interchangeable with a standard liner and several liners may be connected together. The invention may form part of a cooling system, by pumping a fluid at different temperatures into different liners so as to create or increase the airflow up a chimney to cool a dwelling.

Description

TITLE

FLUE LINER HAVING THERMAL ENERGY RECOVERY APPARATUS

DESCRIPTION

Background

In domestic situations with a solid fuel burning open hearth, 80% of the heat produced goes straight up the chimney. In more efficient heat producing appliances such as gas fires and stoves this percentage can be reduced considerably to 10 -20%.

46% of CO2 emissions are due to energy consumption in buildings. Under the revised Building Regulations (L2), new buildings need to prove that they emit 23% less CO2 than buildings designed under the old regulations. The calculation works on a scoring system which allocates points according to the amount of carbon produced by a particular energy source or building material. Renewable systems, including heat recovery, count positively, and can he used to offset less carbon friendly elements of a building either directly or via a carbon trading scheme. All homes are now SAP (Energy) rated, so any renewable energy source can he factored in and save costs elsewhere.

Heat recovery systems have not in general been used in domestic situations because of construction limitations and cost considerations, although some proprietary systems have been proposed. A brief discussion of the most relevant prior art follows.

Belgian patent BE 901241 discloses a twin walled flue liner which can be placed in a chimney of a home. Exhaust gases pass up the centre whilst a fluid can freely circulate in the gap between the walls. The fluid can be pumped to a reservoir or connected to a heating system.

German Patent DE 10054412 discloses a double walled liner (WG) that can be installed in a chimney of a fire place of a dwelling. The double walled liner surrounds a central pipe, which in turn is surrounded by a layer of insulation. The central pipe carries the exhaust gases up the chimney, leaving cooler air free to circulate in the gap between the central pipe and the liner. The cooler air is heated up and is fed into rooms of the dwelling. * 35 *e

Belgian Patent BE 892876 discloses a double walled flue liner having a fluid that can * circulate between the walls and feeds into a heating system. **

* 1J Patent 4MU77 dc'1rp 2 (1rtIh1p,911pd Iinr fnr chimney The liner r,19dp ::::: 40;rii;iu sectionsth;t;rest;ckedtogethe;. pass up the tube * defined by the inner walls, and air is heated in the open space between the inner and outer walls.

It is also known in the prior art to provide heat recuperation systems for homes. These involve either placing a heat exchanging coil in the chimney space (US 4143817, US 4406402), on top of a chimney (US 4699315) or in the fireplace surround (EP005800 I).

A154 001 O0doc None of these provides a satisfactory or controllable way of extracting heat from the waste gases in a domestic chimney.

Various heat recovery systems are used in industrial settings, but these are bolt on' heat exchangers that are attached directly to the exit port of a heat engine. The heat exchangers are bulky and expensive and moreover are unsuitable for use in domestic situations which require low cost installation and maintenance.

The prior art does not provide a flue liner that has the advantages of the invention.

Construction, particularly in the volume house building market is cost led and no additional feature that a typical householder has no need of would be widely installed.

The invention provides a low cost flue liner that can be routinely installed instead of or in conjunction with an existing flue liner and connected for use only if desired. The invention has no moving parts and is hidden from sight.

Summary of Invention

The invention provides a twin walled flue liner as claimed in claimed in claim 1.

Further preferred embodiments are claimed in claims 2-15.

The flue liner is preferably a twin walled flue liner, although the outer wall of the flue liner may be dispensed with in certain installations, in which case the outer wall of the thermal energy recovery apparatus may form or be integral with the outer wall of the liner. The flue liner can have any shape or dimensions that are compatible with a chimney shaft. The liner may be interchangeable with standard liners and may be used to replace all or part of a standard liner.

The thermal energy recovery apparatus is preferably adjacent or integral with the : .. inner wall of the liner to maximise heat transfer. Preferably the inner wall and recovery apparatus is made of a heat conductor such as a metallic conductor to ** maximise heat transfer from the waste gases in the chimney.

An insulating layer or layers may be provided, at least part of which may surround the thermal recovery apparatus. The thermal recovery apparatus may be substantially embedded within an insulating layer. Any suitable insulating material may be used. S...

The thermal energy recovery apparatus may terminate short of an end portion of the * ,..,: 40 liner, or short of both end portions, so that the apparatus is located within the liner at * an optimal position. The apparatus may have fluid communication means extending into an end portion to facilitate connection to other apparatus in adjacent liners.

The liner may have connectors at an end portion for connecting the liner to another liner, which may be a standard liner or a liner according to the invention. The liner may therefore form a part of a modular system.

A154 001 00 dcc The thermal energy recovery apparatus may have inlet and outlet ports extending through the outer wall for passage of a heat transferring fluid. The heat transferring fluid may be water. Valves may be used to control the flow of fluid or prevent passage of fluid so as to bypass the apparatus.

The thermal energy recovery apparatus may comprise a heat exchanger, and may for example be a coil, a mesh or fins arrangement, or a combination thereof. Preferably the heat exchanger is a closely wound helical coil.

The twin walled flue liner may be installed in a domestic chimney, and may be connected to a domestic heating system.

A plurality of twin walled flue liners may be installed at spaced locations in a domestic chimney, the thermal energy recovery apparatus being individually connectable to a domestic heating system.

The invention may form part of a cooling system, by pumping a fluid at different temperatures into different liners so as create or increase airflow up the chimney and cool a dwelling.

Although specifically described and intended for use in non industrial situations such as domestic dwellings, the invention is also of wider application and can be installed in industrial chimneys with few modifications.

Drawings Figure 1 is a partial sectional view of the flue liner according to the invention.

The flue liner 1 shown has an inner wall 3 and an outer wall 5 that are substantially circular. A central shaft 2 defined by the inner wall 3 runs up the centre for the passage of waste products of combustion.

A helical coil 6 is wound in close contact about a length of the outside of the inner wall 3. The walls of the coil 6 may have a flattened side (not shown) to improve contact with the inner wall 3. e

The coil 6 has an inlet port 6a at one end and an outlet port 6b at the other end, by which the coil 6 can be connected to a system such as a domestic heating system.

* . \AJtr c rn.uil, frl ?1tr% t1ii iinrr rr1 rfth r'cii 2n thrriioh tb rutlpt rirrt fh * * S V! 44 t4L 10 44 441) 1144 tJ/J. ffl.l 4 J L 4114' 4/'.J 14.1 1414 I..! 4144 *1 404 1

S

*.S*SS * A thick insulating layer 4 surrounds the coil 6 and is surrounded by the outer wall 5.

In use, hot gases pass up the shaft 2 and heat the fluid in the heat recovery apparatus.

These can be circulated through the heating system to provide hot water to radiators, domestic appliances or baths showers and sinks. When the hearth or heat-producing apparatus is not in use the fluid simply moves through the coil unheated, or alternatively the coil is bypassed to prevent heat loss.

A154 001 O0doc

Claims

1. A twin walled flue liner for use in non-industrial chimneys, the flue liner having an inner wall and an outer wall, with a thermal energy recovery apparatus located therebetween.

2. A twin walled flue liner according to any preceding claim, wherein the thermal energy recovery apparatus is adjacent or integral with the inner wall.

3. A twin walled flue liner according to any preceding claim, further comprising an insulating layer at least part of which surrounds the thermal recovery apparatus.

4. A twin walled flue liner according to claim 3, wherein the thermal recovery apparatus is substantially embedded within the insulating layer.

5. A twin walled flue liner according to any preceding claim, wherein a surface of the thermal energy recovery apparatus forms or is integral with the outer wall of the flue liner.

6. A twin walled flue liner according to any preceding claim, wherein the thermal energy recovery apparatus terminates short of an end portion of the liner.

7. A twin walled flue liner according to any preceding claim, wherein the liner has connectors at an end portion for connecting the liner to another liner.

8. A twin walled flue liner according to any preceding claim, wherein the thermal energy recovery apparatus has inlet and outlet ports extending through the outer wall for passage of a heat transferring fluid.

9. A twin walled flue liner according to any preceding claim, wherein the S.... thermal energy recovery apparatus comprises a heat exchanger.

10. A twin walled flue liner according to claim, wherein the heat exchanger is one of a coil, a mesh or fins arrangement.

11. A twin walled flue liner according to any preceding claim installed in a * --dnmectir chimney

---* 40

* *. * e *

12. A twin walled flue liner according to claim 11, wherein the thermal energy recovery apparatus is connected to a domestic heating system

13. A plurality of twin walled flue liners according to any preceding claim, the liners being installed at spaced locations in a domestic chimney, the thermal energy recovery apparatus being individually connectable to a domestic heating system.

A154 001 00 doc

14. A plurality of twin walled flue liners according to any preceding claim, the liners being installed at spaced locations in a domestic chimney and the thermal energy recovery apparatus individually connectable to a domestic cooling system, which creates or increases airflow up the chimney by pumping a fluid at different temperatures into different thermal recovery apparatus.

1 5. A flue liner substantially as described herein with reference to the drawings. * S * *** *S * S ****

S *

S * S., * . 55S*

S

*** 5*5 * * A154 001 00 doc