GB2265697A - Heating apparatus - Google Patents

Abstract

Heating apparatus comprises an electrical infra-red heater 4, for example, a tungsten halogen lamp with a red quartz outer sleeve which is disposed within a soldered coil heat exchanger 6. Oil is arranged to be circulated through the heat exchanger 6. In use, the infra-red heater 4 heats by radiation oil circulated through the heat exchanger 6. The heated oil is then led to a flat-plate heat exchanger 8 wherein heat passes to circulating water. The circulating water is led to a static water vessel 80 and subsequently via a motorised valve 92 to radiator units (not shown) of a central heating system. Additionally, the heated oil is led in parallel through a heat exchanger (not shown) disposed within a water tank thereby to heat water in the tank. The valve 92 is only opened when the water in vessel 80 reaches a predetermined temperature. The heat exchangers 6, 8 may be surrounded by heat insulating material or the apparatus may be enclosed by an air heating casing. <IMAGE>

Description

HEATING APPARATUS The invention relates to a heating apparatus and particularly, although not exclusively, to central heating apparatus for a domestic central heating system.

A known domestic central heating system comprises a gas-burning boiler which is arranged to heat water directly. The heated water is circulated, via pipework, through radiators and to a central hot water storage tank.

Such a heating system is highly inefficient since gas combustion leads to the production of hot gaseous waste combustion products (carbon dioxide and water) which are dissipated to the surroundings. Additionally, heat transfer from the gas burner to the water to be heated is itself inefficient and a relatively large amount of heat energy is lost to the surroundings. Furthermore, with such a heating system, the gaseous combustion products must be vented safely to the atmosphere and, accordingly, a flue and associated ducting must be provided.

It is an object of the present invention to improve upon the aforementioned situation.

According to a first aspect of the present invention, there is provided heating apparatus comprising an electrically-powered infra-red radiation source and a fluid receptacle, the fluid receptacle being provided adjacent to the radiation source and being arranged such that, in use, with a first fluid within said receptacle, said first fluid may be heated by said radiation source.

Said infra-red radiation source preferably comprises an infra-red emitter element which is surrounded by a protective layer. The protective layer is preferably substantially inert and arranged to transmit infra-red radiation emitted by said infra-red emitter element. Said protective layer and/or a further layer which surrounds said infra-red emitter element may be arranged to convert light energy into infra-red energy. In this respect, said protective layer and/or said further layer may comprise a ruby red quartz layer.

Said infra-red emitter element may comprise a filament, for example, a tungsten filament which is arranged to be heated by a source of electrical energy.

Preferably, said infra-red radiation source comprises an electrically powered lamp. A preferred electrically powered lamp is a quartz halogen, for example, a quartziodine lamp. Suitable lamps include tungsten halogen lamps having a rating of 240 volts. It should be appreciated that lamps rated at 110 volts or even 12 volts may be of utility in some applications.

The receptacle is preferably provided around the infra-red radiation source. Preferably, the receptacle is coiled around the infra-red radiation source. Said receptacle is preferably defined by means of tubing, preferably by means of copper tubing. Where the receptacle is provided around the radiation source, the assembly is preferably substantially enclosed by a thermal insulating material.

The receptacle preferably has a first end and a second end, the heating apparatus being arranged such that fluid may flow in a path between said first and second ends. Where the receptacle is defined by means of tubing said first and second ends are suitably opposite ends of the tubing.

Preferably, the heating apparatus includes a first fluid within said receptacle. Said first fluid is preferably a liquid at 250C and ambient pressure. Said liquid is preferably flowable down to a temperature of 0 C, more preferably down to a temperature of -10 C. The liquid may be flowable down to a temperature of -200C. Preferably, the liquid has a boiling point of greater than 1000C, more preferably of greater than 1500C. The liquid may have a boiling point of greater than 2000C. In the most preferred embodiment the boiling point of the liquid is greater than 300 C Said first fluid preferably comprises an oil as a major constituent. The oil may be a mineral based oil. The fluid may include additives to inhibit, for example, oxidation, foaming and/or corrosion.

The heating apparatus preferably comprises a first fluid circuit which communicates with said aforementioned fluid receptacle. Said first fluid circuit is preferably arranged to lead the first fluid to and away from a first heat exchanger. Said first heat exchanger is preferably arranged to transfer heat, in use, from the first fluid in said first fluid circuit to a second fluid adjacent thereto.

A heating circuit is preferably provided for circulating the second fluid. Said heating circuit preferably comprises one or a plurality of heat emitters, for example, radiators, through which said second fluid flows, in use.

Alternatively or additionally, a vessel, for example, a hot water tank, may be arranged to contain said second fluid, said first heat exchanger suitably being disposed in said vessel.

Said second fluid is preferably predominantly water.

The heating apparatus preferably further comprises a second fluid circuit which communicates with said aforementioned fluid receptacle. Said second fluid circuit may be arranged to lead said first fluid to an away from a second heat exchanger. Said second heat exchanger may be arranged as described in relation to said first heat exchanger.

In a preferred embodiment, said heating apparatus includes a said first fluid circuit arranged to lead said first fluid to and away from a said first heat exchanger and a said second fluid circuit arranged to lead said first fluid to and away from a said second heat exchanger, wherein said first heat exchanger is arranged to transfer heat to a second fluid in a said heating circuit and said second heat exchanger is arranged to transfer heat to a second fluid in a said vessel.

Preferably, a control means is provided for controlling the relative flow rates of fluid in said first and second fluid circuits.

According to a second aspect of the present invention, there is provided heating apparatus which comprises a heating source and a fluid receptacle, the receptacle being provided adjacent to the heating source wherein a first fluid which comprises an oil as a major constituent is provided in said fluid receptacle, the arrangement of the apparatus being such that, in use, heat may be transferred from said heating source to said first fluid.

Said first fluid of said second aspect may include any of the features of the first fluid described with reference to said first aspect.

The heating apparatus of said second aspect may include any feature(s) of the heating apparatus of said first aspect.

According to a third aspect of the present invention, there is provided heating apparatus comprising: a fluid receptacle; a fluid heater means; fluid circulating means for circulating fluid between said fluid receptacle and fluid heater means; temperature sensing means for sensing the temperature of fluid within said receptacle; heated fluid transfer means for transferring heated fluid from said fluid receptacle to a heating device; and valve means for controlling the passage of fluid in said heated fluid transfer means, said valve means being operable in dependence upon the temperature sensed by said temperature sensing means.

A first fluid flow path is preferably defined between said fluid receptacle and said heater means for passage of fluid from said receptacle to said heater means and a second fluid flow path is preferably defined between said fluid receptacle and said heater means for passage of fluid from said heater means to said receptacle, said first fluid flow path preferably communicates with a first part of said receptacle which is below a position of communication of said second fluid flow path with a second part of said receptacle.

Said heated fluid transfer means suitably comprises downstream pipework which preferably communicates with a part of said fluid receptacle towards a bottom region thereof. Said heated fluid transfer means is preferably arranged to transfer fluid to a plurality of heating devices. The or each heating device preferably comprises a heat emitter in which heated fluid is arranged to circulate.

Said valve means is preferably provided downstream of said fluid receptacle, preferably in said downstream pipework, when provided. Said valve means is preferably arranged to be operated when the temperature of fluid, as sensed by said temperature sensing means, reaches a predetermined temperature. Said predetermined temperature may be greater than 50"C, is preferably greater than 700C and is more preferably greater than 850C. Said valve means is preferably operated automatically when said predetermined temperature is attained. To this end, a link means is preferably provided between said temperature sensing means and said valve means. Means may be provided for adjusting the value of said predetermined temperature.

The heating apparatus of the third aspect may include any feature(s) of the heating apparatus of the first and/or second aspects.

The invention extends to a central heating system which comprises a heating apparatus as described in any statement herein.

The invention further extends to the use of an infrared radiation source as described in any statement herein for heating a first fluid as described in any statement herein.

The invention further extends to the use of an oil as described in any statement herein as a heat transfer medium in a heating apparatus as described in any statement herein.

The invention further extends to the use of apparatus according to the third aspect for delivering heated fluid to one or a plurality of heating devices, for example, in the form of radiator units.

Specific embodiments of the present invention will now be described, by way of example, with reference to the accompanying diagrammatic drawing, in which: Figure 1 is a schematic diagram of a central heating apparatus.

The central heating apparatus 2 comprises an elongate infra-red heater 4 which is disposed within a tube-shaped heat exchanger 6. Oil is arranged to be circulated through the heat exchanger 6. In use, the infra-red heater 4 heats oil circulated through the heat exchanger 6. The heated oil is then led via downstream pipework to a flat-plate heat exchanger 8 wherein heat passes from the hot oil on one side of the heat exchanger to circulating water on the other side thereof. The circulating water is led to a static water vessel 80 and subsequently to radiator units (not shown) of a central heating system. Additionally, the heated oil is led through a heat exchanger (not shown) disposed within a water tank thereby to heat water in the tank.

The central heating apparatus 2 will now be described in greater detail.

The infra-red heater 4 is in the form of a tungsten halogen lamp which includes a ruby red quartz outer sleeve. The outer sleeve maximises the heat output of the lamp by converting light energy to heat energy. The lamp is suitably rated at 240 volts and 1.5 Kw. One such suitable lamp is sold under the Trade Mark Sunquartz by Red Ring Electric Limited (Cat. No. 55-821202). For some applications, it may be preferable to use a 3.0 Kw lamp.

The heat exchanger 6 surrounds the heater 4 and comprises a tightly wound coil of copper tubing, with adjacent coils of the tubing being soldered together. The heat exchanger 6 is thermally insulated on its outside.

The flow direction of oil through the heat exchanger 6 is represented by arrows in the Figure.

A first oil path 10 is defined between a region downstream of outlet 12 of the heat exchanger 6 and an inlet 14 of the flat-plate heat exchanger 8. A return oil path 16 is defined between an outlet 18 of the flat-plate heat exchanger 8 and the inlet 20 of the heat exchanger 6.

A second oil path 40 is defined between a region downstream of outlet 12 of the heat exchanger 6 and an inlet of the heat exchanger (not shown) provided in the water tank. A return oil path 42 is defined between an outlet of the heat exchanger provided in the water tank and the return oil path 16, upstream of an oil pump 22.

The oil pump 22 is provided in the return oil path 16 and is arranged to drive oil through the heat exchanger 6, the flat-plate heat exchanger 8 and the heat exchanger (not shown) provided in the water tank.

An expansion vessel 46 is arranged in communication with the first oil path 10 and the return oil path 42 at regions 48 and 50 respectively in order to compensate for expansion or contraction in oil volume which may occur in use as the temperature of the oil varies.

A pressure gauge 70 is provided in the first oil path 10 and an oil safety relief valve 72 is provided in the return oil path 16.

Water to be heated is fed into the flat plate heat exchanger 8 via a water return path 82 which communicates with inlet 30 of the heat exchanger 8. A pump 83 is provided in the water path 82 for pumping water to the heat exchanger 8. The water return path 82 communicates with a water supply path 84, which is used to replenish water circulating to the heat exchanger 8, and with a lower part of the static water vessl 80. The static water vessel 80 also communicates with water path 86 which communicates with heat exchanger 8 and is downstream of outlet 32 thereof. The water path 86 leads fluid to an upper part of the static water vessel 80.

A water outlet 88 is provided at the bottom of the water vessel 80, the outlet communicating with a water path 90. A motorised valve 92 is provided in the water path 90. Downstream of the motorised valve 92, the water path 90 communicates with the radiator units (not shown) of the central heating system.

In use, water is circulated by action of the pump 83 to and from the heat exchanger 8 and water vessel 80 via water paths 82 and 86. During the circulation, the temperature of the water in the vessel 80 is monitored automatically. When the temperature of water in vessel 80 reaches a predetermined level (for example 90 C) the motorised valve 92 is operated automatically and water at a high temperature is injected into the radiator units of the central heating system. Thus, once heated water is injected into the radiator units, the units rapidly reach their working temperature. This contrasts with prior known central heating systems, in which water is gradually heated as it circulates through the entire central heating system with the consequence that the radiator units of the system only gradually reach their working temperature.

Diversion valves, 60, 62, 64 are provided in the first oil path 10, the return oil path 42 and the second oil path 40 respectively for varying the relative oil flow rates to the flat-plate heat exchanger 8 and the heat exchanger (not shown) provided in the water tank. The relative oil flow rates are controlled in response to thermostats which are arranged to monitor the temperature of water flowing through the flat-plate heat exchanger and in the water tank in dependence upon user selected operating parameters.

The oil used in the apparatus 2 suitably has good heat absorbency characteristics and is flowable when hot and cold (for example at less than OOC). Furthermore, the oil should be able to withstand a high temperature (for example 300"C) without breaking down.

One oil which has been found to have practical utility is sold by Castrol (U.K.) Limited under the Trade Mark CASTRO PERFECTO HT5.

It should be appreciated that the central heating apparatus 2 provides an efficient means of energy transfer. It has been found that the infra-red heater 4 is about 90% efficient at converting electrical energy into heat energy. Furthermore, the transfer of this heat energy to the oil has also been found to be relatively efficient.

It should be appreciated that the apparatus 2 obviates the need for a flue, produces no harmful nitro oxides which are produced in conventional gas fired systems, and is highly compact.

Efficiency of the apparatus 2 may be increased further by enclosing the heat exchangers 6, 8 and associated pipework in heat insulating material. As an alternative, the apparatus 2 may be disposed in a box and a fan provided in the box to circulate any heat therein through ducting so as to provide a source of dry heat if required.

The apparatus 2 requires negligible maintenance.

However, periodically it will be necessary to replace the infra-red heater 4. A photocell 80 is provided adjacent the heater 4 so as to detect when the heater 4 is not functioning. Additionally, it will be necessary after some time to replenish and/or replace the oil.

The apparatus 2 incorporates various safety features.

For example, the oil temperature and pressure is monitored and various means are provided for taking appropriate action should the oil temperature or pressure be too high or low. The power supply to the infra-red heater 6 is monitored and the apparatus arranged to automatically shut itself down should any potentially dangerous condition ensue.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings) and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims (15)

1. Heating apparatus comprising an electrically powered infra-red radiation source and a fluid receptacle, the fluid receptacle being provided adjacent to the radiation source and being arranged such that, in use, with a first fluid within said receptacle, said first fluid may be heated by said radiation source.

2. Heating apparatus according to claim 1, wherein said infra-red radiation source comprises an electrically powered lamp.

3. Heating apparatus according to claim 1 or claim 2, wherein the receptacle is provided around the infra-red radiation source.

4. Heating apparatus according to any preceding claim, wherein said receptacle is defined by means of tubing which is coiled around the infra-red radiation source.

5. Heating apparatus according to any preceding claim, wherein the heating apparatus includes a first fluid within said receptacle, said first fluid being flowable down to a temperature of o C and having a boiling point of greater than 1000C at ambient pressure.

6. Heating apparatus according to claim 5, wherein said first fluid comprises an oil as a major constituent.

7. Heating apparatus according to any preceding claim wherein the apparatus comprises a first fluid circuit which communicates with said fluid receptacle, said first fluid circuit being arranged to lead the first fluid to and away from a first heat exchanger, said first heat exchanger being arranged to transfer heat, in use, from the first fluid in said first fluid circuit to a second fluid adjacent thereto.

8. Heating apparatus according to claim 7, wherein a heating circuit is provided for circulating the second fluid, said heating circuit comprising one or a plurality of heat emitters.

9. Heating apparatus according to any preceding claim, wherein the heating apparatus further comprises a second fluid circuit which communicates with said fluid receptacle, said second fluid circuit being arranged to lead the first fluid to and away from a second heat exchanger.

10. Heating apparatus which comprises a heating source and a fluid receptacle, the receptacle being provided adjacent to the heating source, wherein a first fluid which comprises an oil as a major constituent is provided in said fluid receptacle, the arrangement of the apparatus being such that, in use, heat is transferred from said heating source to said first fluid.

11. Heating apparatus comprising: a fluid receptacle; a fluid heater means; fluid circulating means for circulating fluid between said fluid receptacle and fluid heater means; temperature sensing means for sensing the temperature of fluid within said receptacle; heated fluid transfer means for transferring heated fluid from said fluid receptacle to a heating device; and valve means for controlling the passage of fluid in said heated fluid transfer means, said valve means being operable in dependence upon the temperature sensed by said temperature sensing means.

12. Heating apparatus according to claim 11, wherein a first fluid flowpath is defined between said fluid receptacle and said heater means for passage of fluid from said receptacle to said heater means and a second fluid flowpath is defined between said fluid receptacle and said heater means for passage of fluid from said heater means to said receptacle, said first fluid flowpath communicating with a first part of said receptacle which is below a position of communication of said fluid flowpath with a second part of said receptacle.

13. Heating apparatus according to claim 11 or claim 12, wherein said heated fluid transfer means comprises downstream pipework which communicates with a part of said fluid receptacle towards a bottom region thereof, said heat fluid transfer means being arranged to transfer fluid to a plurality of heating devices.

14. Heating apparatus according to any of claims 11 to 13, wherein said valve means is provided downstream of said fluid receptacle and is arranged to be operated when the temperature of fluid, as sensed by said temperature sensing means, reaches a predetermined temperature.

15. Heating apparatus substantially as hereinbefore described with reference to the accompanying drawings.