GB2194330A

GB2194330A - Water heaters

Info

Publication number: GB2194330A
Application number: GB08615828A
Authority: GB
Inventors: Peter John Hall
Original assignee: Carver and Co Engineers Ltd
Current assignee: Carver and Co Engineers Ltd
Priority date: 1986-06-27
Filing date: 1986-06-27
Publication date: 1988-03-02
Anticipated expiration: 2006-06-27
Also published as: GB8615828D0; GB2194330B

Abstract

A gas fired water storage heater has a vertical heat exchange wall 34 between a combustion chamber 42 and a water reservoir 13A, and a thermoelectric generator 200,201 secured in a lower part of the combustion chamber to a lower part of the wall 34 to utilise part of the heat produced to generate electricity, to be supplied to the controls for the heater. <IMAGE>

Description

SPECIFICATION Energy utilisation apparatus This invention concerns apparatus for utilising heat produced by- a burner.

It is known from our British Patent Applications Nos. 2153989A and 2154314A to provide gas fired water heaters with an electrical control system which operates on a low voltage DC supply, e.g. from a battery. The electrical control system is arranged to minimise the current consumption, and may include a thermocouple to produce sufficient current to hold open a solenoid controlled gas supply valve when a burner of the heater is firing.

Such heaters are extremely useful in caravans, boats, chalets and like structures which lack a mains electricity supply. However dry cell (non-rechargeable) batteries are expensive and have a limited life; and rechargeable batteries need recharging at intervals which can be inconvenient and expensive.

According of the invention is to enable such inconvenience and expense to be reduced.

According to the present invention there is provided apparatus comprising a fluid fuel fired burner, control means for controlling the burner, a combustion chamber above the burner, and a heat exchanger arranged to be heated by heat produced by combustion in said combustion chamber and to transfer heat to a liquid in contact with the heat exchanger; wherein: a solid state thermoelectric generator is in terposed in said apparatus between parts of said combustion chamber and heat ex changer to absorb some of the heat pro duced by combustion and transfer heat to the liquid whereby to produce electricity during firing of the burner.

Said thermoelectric generator is preferably mounted in contact with a wall part of the heat exchanger interposed between the generator and the liquid.

The liquid is preferably held in a reservoir in contact with the heat exchanger. The heat exchanger preferably extends to beyond said generator in said combustion chamber to absorb heat from heated matter, such as combustion products, which has flowed past the generator.

The control system is preferably electrically operated and is provided with power input terminals for connection to a DC power supply, and is preferably arranged to connect the generator output with said terminals for recharging the power supply source.

The rated output of the generator is preferably at least one order of magnitude greater than the maximum electrical power consumption of the control means.

The generator is preferably arranged so that it is exposed, in use, to a high, preferably substantially maximum, thermal gradient between the combustion chamber and the liquid.

The invention will be described further by way of example, with reference to the accompanying drawings which show a water heater substantially as disclosed in our aforementioned specifications with modification to incorporate a thermoelectric generator; and in the drawings: Figure 1 shows a vertical longitudinal crosssection through the apparatus as installed in a habitable structure, such as a caravan, at the junction of a wall and a floor of the structure; Figure 2 shows a plan view of a replaceable burner and control unit of the apparatus, and indicates a remote control and indicator unit; Figure 3 shows a combined air inlet and exhaust outlet device of the apparatus in rear elevation; Figure 4 shows the apparatus in front elevation with the combined device removed to reveal a heater unit of the invention;; Figure 5 shows the heater unit in front elevation with the burner and control unit removed to reveal a main body of the heater unit.

The parts of the apparatus indicated by reference numerals within the range of 1 to 125 and their interrelationship are described in the aforementioned specifications which descriptions are incorporated herein by reference to form part of this specification.

The apparatus includes a thermoelectric generator 200 which is clamped to a lower part of the main wall 34 so as to project into the lower part 42 of the combustion chamber 41,42 below the fins 43 of the main body 14 which serves as a heat exchanger to conduct heat from the combustion chamber to the reservoir 1 3A via the wall 34. In this embodiment the generator 200 extends sidways across the combustion chamber to the side walls 40 and is provided with vertical fins 201 which extend forwards across the combustion chamber to or to close to the insulation 96 on the partition 51, and is disposed just above the flame zone 92 of the combustion chamber above the burner 80. The generator may, however, extend only partiqlly across the combustion chamber.Heat resistant leads (202) connect the generator electrically with the control unit 15, which is arranged to unblock or complete a circuit via the unit 99 to a power supply unit 203 for recharging the unit 203 when the voltage of the generator output reaches a sufficient level after ignition of the burner.

The blocking of the circuit may be provided simply by a diode. The unit 99 may include a charging indicator light.

The invention is not confined to details of the foregoing example, and there is generally provided, in accordance with the invention, fluid heater apparatus wherein a burner is arranged to produce a flow of heated matter which flow is directed firstly to a thermoelec tric generator and thereafter to heat exchanger means both of which are arranged to heat a liquid so that a significant proportion of the heat of said flow which is not absorbed by the generator is subsequently absorbed by said heat exchanger means and transferred to said liquid.

The apparatus has the major advantage of being able to produce useful quantities of electricity without significant impairment of its efficiency as a water heater.

The heat exchanger and the generator may be arranged to suit the construction of other forms of fluid heater, e.g. they could be mechanically separated and linked by a flue to heat separate flows or portions of a flow or reservoir of liquid, but an integrated arrangement as illustrated in the drawings is preferred for efficiency of operation and construction.

Claims

1. Apparatus comprising a fluid fuel fired burner, control means for controlling the burner, a combustion chamber above the burner, and a heat exchanger arranged to be heated by heat produced by combustion in said combustion chamber and to transfer heat to a liquid in contact with the heat exchanger; wherein a solid state thermoelectric generator is in terposed in said apparatus between parts of said combustion chamber and heat ex changer to absorb some of the heat pro duced by combustion and transfer heat to the liquid whereby to produce electricity during firing of the burner.

2. Apparatus as claimed in Claim 1 wherein the thermoelectric generator is mounted in contact with a wail part of the heat exchanger interposed between the generator and the liquid.

3. Apparatus as claimed in Claim 1 or 2 wherein the liquid is held in a reservoir in contact with the heat exchanger.

4. Apparatus as claimed in Claim 1, 2 or 3 where in the heat exchanger extends to beyond said generator in said combustion chamber to absorb heat from heated matter such as combustion products, which has flowed past the generator.

5. Apparatus as claimed in Claim 1, 2, 3 or 4 wherein the control system is electrically operated and is provided with power input terminals for connection to a DC power supply, and is arranged to connect the generator output with said terminals for recharging the power supply source.

6. Apparatus as claimed in Claim 5 wherein the rated output of the generator is at least one order to magnitude greater than the maximum electrical power consumption of the control means.

7. Apparatus as claimed in any preceding claim wherein the generator is arranged so that it is exposed, in use, to a high, preferably substantially maximum, thermal gradient between the combustion chamber and the liquid.

8. Fluid heater apparatus wherein a burner is arranged to produce a flow of heated matter which flow is directed firstly to a thermoelectric generator and thereafter to heat exchanger means both of which are arranged to heat a liquid so that a significant proportion of the heat of said flow which is not absorbed by the generator is subsequently absorbed by said heat exchanger means and transferred to said liquid.

9. Apparatus as claimed in any preceding claim wherein the thermoelectric generator is arranged substantially as hereinbefore described with reference to the accompanying drawings.