WO2012100781A2

WO2012100781A2 - Catalytic heating system

Info

Publication number: WO2012100781A2
Application number: PCT/DK2012/050031
Authority: WO
Inventors: Frederik GUNDELACH; Hans MØLLER
Original assignee: Heatgear Professional ApS
Current assignee: Heatgear Professional ApS
Priority date: 2011-01-28
Filing date: 2012-01-25
Publication date: 2012-08-02
Anticipated expiration: 2013-07-28
Also published as: WO2012100781A3

Abstract

The present invention concerns a catalytic, preferably flameless, heating system, using a combustible gas for heating of a medium such as water while limiting harmful emissions and saving energy.

Description

Catalytic Heating System

The present invention relates to a heating system. In particular, the present invention concerns a catalytic, preferably flameless, heating system, using a combustible gas for heating of a medium such as water.

Technical Background

Catalytic heating systems, using flameless, catalytic reaction, are known from the International patent applications WO 2007/085251 and WO 2009/003481.

Conventional boilers are known, wherein fuel is burned and the produced hot gases are passed through a heat exchanger wherein much of their heat is transferred to water, thus raising the temperature of the water.

Condensing boilers are water heaters wherein waste heat in flue gases is used to pre-heat the cold water entering the boiler. They may be fuelled by gas or oil, and are called condensing boilers because the water vapor produced during combustion is condensed into water, which leaves the system via a drain. Condensing boilers are replacing earlier conventional designs. Typical models offer efficiencies of 90%, compared to 70-80% for conventional boilers.

A combi boiler provides heating and hot water directly from the boiler.

Summary of the invention

There exists a need to limit emissions of harmful substances, such as C0₂ and NOx.

There exists a continued need for energy saving. Further, there is a need for an economical water tank heating system. Additionally, a heating system which does not take up unnecessary space is preferable or needed in many practical applications.

Surprisingly, it has been discovered that a heating system using catalytic heating provides a clean, economic, energy efficient system, which additionally saves space as compared to e.g. a condensing boiler.

According to an aspect the invention concerns a use of a catalytic heating element to reduce the emissions of C0₂ emerging from using a fluid fuel for heating, by supplying the fluid fuel and a fluid which comprises oxygen to said catalytic heating element and allowing said fluid fuel and said fluid which comprises oxygen to react in a catalytic reaction; and by allowing a medium which comprises water to absorb heat energy from the catalytic reaction, transferred as heat radiation and at least one of heat conduction and heat convection, by having said medium at least partly surrounding said catalytic heating element.

According to an aspect the invention concerns a use of a catalytic heating element to reduce the harmful emissions emerging from using a fluid fuel for heating, by supplying the fluid fuel and a fluid which comprises oxygen to said catalytic heating element and allowing said fluid fuel and said fluid which comprises oxygen to react in a catalytic reaction, any by allowing a medium which comprises water to absorb heat energy from the catalytic reaction by heat radiation and at least one of heat conduction and heat convection, by allowing said medium to at least partly surround said catalytic heating element.

According to an aspect the invention concerns a use of a catalytic heating element to reduce energy losses emerging from using a fluid fuel for heating, by supplying the fluid fuel and a fluid which comprises oxygen to said catalytic heating element and allowing said fluid fuel and said fluid which comprises oxygen to react in a catalytic reaction; and by allowing a medium which comprises water to absorb heat energy from the catalytic reaction by heat radiation and at least one of heat conduction and heat convection, by allowing said medium to at least partly surround said catalytic heating element.

According to an aspect the invention concerns a method for lowering harmful emissions upon use of a combustible fluid for heating, said method comprising: Using a catalytic heating element to heat a medium, said catalytic heating element being at least partly surrounded by said medium, allowing a combustible fluid to react with oxygen in a substantially flameless reaction.

According to an aspect the invention concerns a water tank heating system comprising: A water tank; A solar heating system connected to said water tank, for heating the water of said water tank; A heating system or unit comprising a catalytic heating element, said catalytic heating element being immersed in the water of said water tank, allowing heating the water of the water tank with a combustible fluid.

According to an aspect the invention concerns a combination condensing boiler comprising: A water tank; and a catalytic heating element, optionally as part of a heating system or unit, said catalytic heating element being immersed in the water of said water tank, allowing heating the water of the water tank with a combustible fluid.

According to an aspect the invention concerns an absorption heat pump for space heating comprising a catalytic heating element.

According to an aspect the invention concerns a heating system (401) for flameless catalytic heating of a medium, said heating system allowing catalytic reaction, said heating system comprising: A housing with an inlet (408) for a combustible fluid, inlet (406) for a fluid, said fluid containing oxygen, and outlet (405) for the reaction products from the catalytic reaction; A countercurrent exchange zone (404) having a heat conducting wall in the housing, said countercurrent exchange zone (404) being in fluid communication with at least one inlet and outlet, said heat conducting wall partitioning inlet and outlet, allowing heat exchange through said heat conducting wall between, on one side, added combustible fluid and/or fluid which contains oxygen, and on the other side, the reaction products; said countercurrent exchange zone (404) preferably being thermally isolated from the medium, which is being heated, by a thermally isolating wall; A heating unit, said heating unit comprising: A chamber (415) having a chamber wall, at least part of said chamber wall being made from a substantially I transparent material, and at least part of said chamber wall allowing thermal conduction of heat to the medium, which is being heated, said chamber wall surrounding a catalytic burning zone (402) and a cooling zone (403); said countercurrent exchange zone (404), burning zone (402) and cooling zone (403) being in fluid communication, allowing fluids to pass from inlet, through the countercurrent exchange zone (404) to the burning zone (402), further to the cooling zone (403), and back through the countercurrent exchange zone (404) to the outlet; said catalytic burning zone (402) comprising a catalytic burner (414), allowing combustible fluid and the fluid which contains oxygen to react, forming reaction products, preferably by a flameless, catalytic reaction.

According to an aspect the invention concerns a heating unit for heating a medium with a combustible fluid and a fluid which contains oxygen, said heating unit comprising: A chamber (415) having a chamber wall, at least part of said chamber wall being made from a substantially IR transparent material, and at least part of said chamber wall allowing thermal conduction of heat to the medium, which is being heated, said chamber wall surrounding a catalytic burning zone (402) and a cooling zone (403); said burning zone (402) and cooling zone (403) being in fluid communication, allowing fluids to pass from the burning zone (402) to the cooling zone (403); said catalytic burning zone (402) comprising a catalytic burner (414), allowing combustible fluid and the fluid which contains oxygen to react, forming reaction products, preferably by a flameless, catalytic reaction.

According to an aspect the invention concerns a use of the heating system or the heating unit, for heating water in an apparatus selected among an immersion heater, a hot water tank, a dishwasher and a washing machine.

According to an aspect the invention concerns a method for heating a liquid in a container, said liquid preferably comprising water, using a heating system or a heating element, said method comprising surrounding said heating element at least partly with the liquid, providing a space filled with liquid of at least 1 cm, preferably 2 cm, more preferred at least 3 cm, preferably 4 cm, more preferred at least 5 cm, from the part of the surface of the chamber, which is IR transparent, to the surrounding container.

According to an aspect the invention concerns a method for heating of a medium, preferably water, by catalytic, preferably flameless, combustion of a gas, said gas comprising methane, wherein said catalytic reaction is conducted at a temperature of at least 500°C, more preferred at least 600°C, preferably at least 700°C, more preferred at least 750°C, preferably around 800°C, in a container, wherein at least part of said container is made of an IR transparent material, preferably a material selected among aluminum, copper, quartz, or mixtures or alloys comprising any of these materials.

Detailed Disclosure

The term "IR transparent material" is used about a material, which is substantially transparent with respect to IR radiation with a wavelength of about 3-7 μιη, preferably 3-10 μιη. IR

transparent materials comprise, but are not limited to, aluminum, copper, and quartz, alloys comprising any of these, as well as mixtures comprising these. Aspects, embodiments and features of the invention are described in the claims, description and figures.

The emissions may be measured as the amount of harmful emissions, e.g. C0₂, emerging by generating a specific amount of useful heat energy, i.e. energy losses are reduced. Alternatively, harmful emissions are total amount of emitted C0₂ measured with respect to the useable heat energy generated by the reaction of a specific amount of fluid fuel.

According to an embodiment, the invention concerns a use, wherein the heating is used for heating air for a living space in buildings or means for transportation. Accordingly, water in a tank or container may act as an intermediary, e.g. for heat absorption and/or transfer.

According to an embodiment, the reduction of C0₂ may be measured with respect to the amount of energy provided as useful heated air. The heated air may e.g. be used for heating space, such as housing, domestic or commercial premises or a car, such as an electrical car.

According to an embodiment, the invention concerns a use, where the fluid which comprises oxygen is air.

In principle, the fluid which comprises oxygen may be pure oxygen, but for many practical applications, a lower content of oxygen is preferred, such as the concentration of oxygen in air or lower.

According to an embodiment, the invention concerns a use, wherein said harmful emissions are NOx. The present invention allow having a lower reaction temperature, such as in the range of 600-800°C, compared to the conventional open flame reaction temperature of 1200-2000°C. According to an aspect the invention concerns a use of a catalytic heating element to reduce energy losses emerging from using a fluid fuel for heating, by supplying the fluid fuel and a fluid which comprises oxygen to said catalytic heating element and allowing said fluid fuel and said fluid which comprises oxygen to react in a catalytic reaction; and by allowing a medium which comprises water to absorb heat energy from the catalytic reaction by heat radiation and at least one of heat conduction and heat convection, by allowing said medium to at least partly surround said catalytic heating element.

The medium may suitable comprise or be water. When the catalytic heating element is surrounded, at least partly, by water, very little energy losses occurs.

According to an embodiment, the invention concerns a method, wherein said harmful emissions are selected among C0₂ emissions and NOx emissions.

According to an embodiment, the invention concerns a method or use, wherein said medium is contained in a tank, said tank being selected among a tank for a solar heating system, a tank for a generator in an absorption heat pump, and a tank for a combination condensing boiler.

In a conventional condensing boiler it is necessary to heat the water in the central heating system in order to heat the water of the hot water tank. During periods wherein there is no need for space heating, it is a waste of resources to heat the water of the central heating system, as there is no need for the heat energy which is used for the water of the central heating system.

A conventional boiler or furnace has very low efficiency during the hot summer months. As opposed to this, the present method and systems provides an improved efficiency during the summer, which is comparable to the efficiency during the winter.

According to an embodiment, the invention concerns a method or use, wherein the heating is for heating space, such as housing, domestic or commercial premises, or a car, such as an electrical car.

A catalytic heating element may be used e.g. in a heat exchanger in an electric car. Many drivers use the major part of the time in the car waiting in queues. In an electric car, this means a large proportion of the energy is used for heating or cooling (AC) the car, reducing the effective range of the car. By adding a catalytic heating element, run on a fluid fuel, for heating and/or cooling, the range of the car may be increased significantly, while still preserving the green profile of the car, due to the reduced emissions provided by the present invention.

According to an embodiment, the invention concerns a method or use, wherein said combustible fluid is selected among hydrogen and fossil fuel.

According to an embodiment, the invention concerns a method or use, wherein said medium comprises water. According to an aspect the invention concerns a water tank heating system comprising: A water tank; A solar heating system connected to said water tank, for heating the water of said water tank; A heating system or unit comprising a catalytic heating element, said catalytic heating element being immersed in the water of said water tank, allowing heating the water of the water tank with a combustible fluid.

According to an embodiment, the invention concerns a water tank heating system, wherein said catalytic heating element is positioned in the lower half of said water tank, preferably in the lower third of said water tank.

Known combination condensing boilers or combi boilers provide reduced efficacy as measured throughout the year, when used in areas with varying energy needs during the year, e.g. due to seasons.

The present systems may use an amount of water, equivalent to the amount of DHW usually present in a water tank, and dispense with the need of an external circuit, thereby reducing the amount of necessary pipes. This in itself facilitates installation and reduces the price. Further, the simpler plumbing reduces heat losses significantly.

For an ordinary one-family house a tank of about 100 liter will be adequate, providing 25 kW boiler effect. Such a system may increase operating time, and provide more water to be heated by a solar collector.

According to an embodiment, the invention concerns a water tank, wherein part of said catalytic heating element is made of quartz, allowing I radiation to pass through the quartz, thereby heating the water.

According to an aspect the invention concerns an absorption heat pump for space heating comprising a catalytic heating element. This aspect may be applied for an electric car heating and/or comfort system.

According to an embodiment, the invention concerns an absorption heat pump, further comprising a generator having a water tank, wherein said catalytic heating element is situated in said water tank of said generator. The water tank may e.g. comprise water, a mixture of ammonia and water, or a mixture of lithium bromide and water.

According to an embodiment, the invention concerns a heating system, wherein said cooling zone (403) comprises cooling cells (419) for the reaction products, whereby the cooling zone allows condensation of the reaction products.

According to an embodiment, the invention concerns a heating system, wherein said cooling zone (403) further comprises a thermally isolating and preferably IR-reflecting element (418) for thermal separation of the catalytic burner (414) and the cooling cells (419).

According to an embodiment, the invention concerns a heating system, for heating a medium in a container, said heating system further comprising means, such as a flanged joint (411) or an adaptor, allowing fixation of said heating system to said container comprising the medium which is heated.

According to an embodiment, the invention concerns a heating system, for heating a medium in a container, said heating system being shaped such that a single opening in the container is sufficient to allow installation of said heating system and subsequently heating the medium.

According to an embodiment, the invention concerns a heating system, for heating a medium in a container having a wall, said heating system being shaped such that the wall of the chamber (415) may constitute a part of the wall of the container.

According to an embodiment, the invention concerns a heating system, for heating a medium in a container, the container being a hot water tank, a pipe or a counter flow water heater.

According to an embodiment, the invention concerns a heating system, wherein the cooling zone (403) is placed such that the cooling zone (403) is in contact with the medium, which is heated, preferably between the flange (411) and the catalytic burning zone (402). According to an embodiment, the invention concerns a heating system, wherein the part of the chamber (415), which surrounds the cooling zone (403), is shaped as cooling fins, forming cooling cells (419).

According to an embodiment, the invention concerns a heating system, wherein the shape of the cooling fins (419) allows a formed condensate to be captured and lead to an independent outlet for draining, preferably in a condensation drain (416).

According to an embodiment, the invention concerns a heating system, further comprising a counterflow heat exchanger (407) in the area around the external side of an exhaust manifold (417) and the internal side of an external cover (422), allowing heat exchange between reaction products and supplied fluids.

According to an embodiment, the invention concerns a heating system, further comprising a combined transport and distribution pipe (413), allowing supply of fluids to the catalytic burner (414) to be conducted by said combined transport and distribution pipe (413), which is concentrically placed and in parallel with respect to the catalytic burner (414), said transport and distribution pipe (413) extending to the bottom of the catalytic burner (414).

According to an embodiment, the invention concerns a heating system, wherein the medium, which is heated, is a fluid, preferably a liquid, more preferred a liquid which contains water, preferably water.

According to an embodiment, the invention concerns a heating system, wherein the wall of the chamber (415) is made in a material transparent with respect to infrared radiation, which is impervious to fluid for immersion in liquids, preferably a material selected among aluminum, copper, and quarts, or mixtures or alloys comprising any of these materials.

According to an aspect the invention concerns a heating unit for heating a medium with a combustible fluid and a fluid which contains oxygen, said heating unit comprising: A chamber (415) having a chamber wall, at least part of said chamber wall being made from a substantially IR transparent material, and at least part of said chamber wall allowing thermal conduction of heat to the medium, which is being heated, said chamber wall surrounding a catalytic burning zone

(402) and a cooling zone (403); said burning zone (402) and cooling zone (403) being in fluid communication, allowing fluids to pass from the burning zone (402) to the cooling zone (403); said catalytic burning zone (402) comprising a catalytic burner (414), allowing combustible fluid and the fluid which contains oxygen to react, forming reaction products, preferably by a flameless, catalytic reaction.

According to an embodiment, the invention concerns a heating unit, wherein said cooling zone

(403) comprises cooling cells (419) for the reaction products, whereby the cooling zone (403) allows condensation of the reaction products.

According to an embodiment, the invention concerns a heating unit, wherein said cooling zone (403) further comprises a thermally isolating and preferably IR-reflecting element (418) for thermal separation of the catalytic burner (414) and the cooling cells (419). According to an aspect the invention concerns a use of the heating system or the heating unit, for heating water in an apparatus selected among an immersion heater, a hot water tank, a dishwasher and a washing machine.

According to an aspect the invention concerns a method for heating of a medium, preferably water, by catalytic, preferably flameless, combustion of a gas, said gas comprising methane, such as natural gas which comprises methane, wherein said catalytic reaction is conducted at a temperature of at least 500°C, more preferred at least 600°C, preferably at least 700°C, more preferred at least 750°C, preferably around 800°C, in a container, wherein at least part of said container is made of an IR transparent material, preferably a material selected among aluminum, copper, quartz, or mixtures or alloys comprising any of these materials.

According to an embodiment, the invention concerns a method, wherein the site of said catalytic reaction takes place is at least partly surrounded by said medium.

According to an aspect of the present invention it concerns a heating system for heating of a medium comprising water, such as, but not limited to, heating of housing, absorption heat pumps, process water, etc., using catalytic IR radiation combined with heat convection.

According to an aspect the present invention concerns an effective stationary generic and modular catalytic heating system, adapted to be mounted and/or flanged on a container comprising the medium, which is to be heated, in principle in the same manner as an electric heating cartridge. The part of the catalytic heating cartridge, which is placed on the side of the mounting flange or adaptor, which is not surrounded by the medium to be heated, contains inlet and outlet, respectively, for the non-reacted gas air mixture and the emissions, which are the product of the catalytic reaction (exhaust).

According to an aspect the present invention relates to heating of liquids which contains water. The catalytic heating cartridge may be designed as a generic immersion heater, having a performance, which may be scaled up or down, implying a wide range of applications of the catalytic heating cartridge, comprising, but not limited to, stationary purposes such as heat pumps (such as gas heat pumps, adsorption heat pumps), gas cooling pumps and refrigerators, heating cartridge, e.g. for use in domestic appliances, such as, but not limited to, washing machines, dishwashers, tumble dryers, hot water for personal hygiene, hot water for space heating via hot water tanks, boilers, or as booster in a micro CHP plants and/or existing heat pumps.

According to an aspect, the present invention provides freedom with respect to selecting fluid, such as liquid or gas, fuel, which may be fossil, sustainable, and C0₂ neutral. The reaction which the build-in catalyst promotes between e.g. hydrocarbon in the fuel and oxygen in the inlet air, is an exothermic process, which takes place at a far lower temperature compared to an open flame, which is the reason why catalysis is the most appropriate method for reduction and/or elimination of harmful emissions, of e.g. CH, CO, C0₂, NOx and particles. CH and CO is inter alia reduced due to the catalytic process, C02 is reduced due to the increased efficiency, and NOx is inter alia reduced due to the lower reaction temperature.

Examples of applicable fuels are diesel, biodiesel, ethanol, gasoline, kerosene, jet propellent (such as JP8), methanol, butane, propane, natural gas, biogas, methane, hydrogen, and mixtures comprising any of these.

The present invention provides an extremely efficient and compact construction, having a very low heat load, providing longevity of the materials, and a very high thermal efficiency. The catalytic heating element may, due to the particular design, be made condensing.

The invention may, according to an aspect, abide to the definitions of a Clean Tech product, having a definition, inter alia saying: "Has shown a convincing efficiency by having a lower cost structure, while the invention may reduce the environmental impact (compared to an electrical heating cartridge, the C0₂ reduction may be as much as 70% depending on the way of manufacturing the used electricity). These are properties, which makes the present invention a contributing factor for a more productive and responsible application of the resources of the world".

Figure 1 and 2 shows an embodiment of a catalytic heating system in a configuration allowing the application of a fuel in the gaseous phase for heating a medium which contains water. The design of such a multi-fuel based catalytic heating system makes it possible to place the catalytic heating element directly in the medium which has to be heated. The heating element consists of a catalytic IR burner, which heats the medium to be heated, by a combination of infrared radiation and heat convection. In a practical application a catalytic IR burner will provide up to about 70% of its energy as radiation heat, while the remaining about 30% will be provided partly to the exhaust gas as convection heat (20%), and partly as visible UV-light etc. (about 10%). This means the invention is very energy efficient, and furthermore gives of only very limited harmful emissions. In particular the NOx values are very low or non-existent due to the low reaction temperature. The catalytic IR burner may consist of a cylindrical or flat catalytic element made of ceramics, metal or fiber material.

For comparison with traditional heating systems for housing and industrial purposes, etc, the major difference is that traditional heating occurs from the outside and into the material or medium to be heated, providing a somewhat poor efficiency due to the heat losses to the surroundings.

The present invention provides a catalytic infrared heating combined with a conduction and/or convection heating in a heating element, which may be combination of an IR transparent pipe and a preferably condensing cooling zone, having a geometry and a central placement in a cavity where the medium is to be heated, which provides the possibility of having the unit completely or partly surrounded by the medium to be heated. The heating may happen from the inside and out of the heating element, which is also the case with an electrical heating element, which is flanged on a container. This may provide a more effective and/or efficient heating of the medium, which is to be heated. Catalytic heating occurs in the temperature interval of 400-800°C, depending on the fuel, which is used. These temperatures corresponds to an I wavelength of about 3-10μιη. This means that the emission specter of the IR radiation is almost coincident with the maximum absorption specter for water, which is in the range 3-10μιη.

For this reason IR heating is very appropriate for the heating of water containing mediums.

The infrared radiation is an entirely thermal effect, and does not in itself imply any immediate safety concerns for persons, operating the technology.

The present heating system is preferably surrounded by the medium to be heated, implying the need for an e.g. watertight separation between the medium and the catalytic heating element. In order to increase the efficacy of transfer of the IR radiation a separation wall may be established, which is made of a material, which may be optimized with respect to transmission of IR radiation as well as convection heat. The separation wall may e.g. consist of aluminum, copper, or quartz, or a combination of any of these.

Catalytic flameless heating principles are inter alia useful for use in hazardous areas: Catalytic infrared heating is inter alia approved for Factory Mutual for Class 1, Division 2, Group D, and Canadian Standards Association for Class 1, Division 1, Group D hazardous locations.

A flameless catalytic heating element is useful for work in hazardous areas such as e.g. chemical and petro-chemical storage sites, and places where flammable or explosive gasses or vapors may occur. A flameless catalytic heating system according to the present invention may also work safely in areas with flammable dust or metal dust, as well as in building areas, where gas fueled vehicles are being maintained, stored or parked.

The present invention, which according to an embodiment is a flameless catalytic, scalable and modular heating system, may allow the heating of mediums containing water directly using fossil and/or sustainable fuels, or a combination, providing a reduction of C0₂ emissions of up to 70% compared to heating using electrical energy.

It will inter alia be possible to establish absorption heat pumps, which are being heating using the present invention, allowing dispensing with the use of electrical energy to run a compressor based heat pump as well as using electrical energy for running the build-in heating cartridge, which is going to be running each time the weather impedes the heat pump to produce the necessary heat, in order to maintain the desired comfort temperature in e.g. housing. Calculations show that a standard house may save about 4.700 kg C0₂ each year, by changing from an electrical compressor based heat pump to an absorption heat pump running on gas. If C0₂ neutral fuels are used for running the absorption heat pump the C0₂ emission may be reduced by 8.850 kg every year. In the case where the change is from usual oil or gas fired heating of a standard housing, the possibilities for saving C0₂ will be even larger. Using the present invention, which according to an embodiment is a flameless catalytic, scalable and modular heating system, it may be possible to provide a shift in paradigm of the conception of a gas fired residential boiler, and the amount of space necessary. Accordingly, the present invention allow replacing the traditional condensing residential boiler or a combi boiler, which uses either gas, heating oil or solid fuel, with a catalytic heating cartridge.

In large parts of the geographical areas, wherein a distribution net for natural gas has been established, in Europe (95 million households) and the USA (65 million households), it is today profitable to establish solar collectors on the roofs of residential buildings, for use in heating of DHW in the summer months. The heated water will usually be contained in an accumulator tank which is provided with a heating coil, capable of transferring the collected heat energy from the solar collector to the DHW in the accumulator tank. In order to make sure that the residents have DHW in the periods of the year wherein the solar collectors cannot produce sufficient energy for heating of the DHW, most accumulator tanks have been provided an additional heating coil or heating pipe or hose, which is connected to the water based central heating or district heating of the housing, which either by district heating or a residential boiler will allow transfer of the necessary energy to the DHW in the boiler room of the residential housing.

All experiences show that in an one-family house the accumulation tank should have a capacity of about 400 liters, in order for the investment in a solar collector for heating of the DHW may be economically viable. Operational experiences further show that for conventional systems, peak loads for DHW in the summer months may be profitably handled using an electrical heating cartridge mounted in the hot water tank. Starting a residential boiler or using district heating only to supply the heating of DHW in short periods is associated with large losses. The described, conventional hybrid system, comprising a solar collector, hot water tank, residential boiler/district heating connection, and electrical heating cartridge may be optimized considerably, e.g. with respect to reduction of harmful emissions and reduction of energy costs, by replacing the heating cartridge running on electrical energy and the residential boiler with a flameless catalytic heating system according to the present invention, which is placed directly in the mentioned hot water tank. By such an arrangement we can assure that the running cycles for a flameless and condensing heating element may be optimized with respect to energy losses and clean combustion. Figure 1 show such as system solution. The advantages comprise that the user saves as much space as the earlier residential boiler has freed. There will always be sufficient DHW available, in sufficient amounts to economically and environmentally advantageously connect e.g. a dishwasher and/or a washing machine to the DHW, thereby replacing the electrical current, which is usually used for heating of the water in domestic appliances. Thereby a standard family may further save about 800 kg C0₂ each year.

Recent experimental results indicate that also non-liquid heating systems, such as air conditioning and hot air heating, may save considerable economical and environmental resources (about 45- 100% reduction of the C0₂ emission, depending on the chosen fuel) by changing from the electrical compressor heat pump systems for running the air based heating/cooling system, to absorption based heat pump systems, which are run by heat produced from fossil or sustainable fuels. The described flameless catalytic heating unit will be very suitable for heating of an absorption based cooling and/or heating system e.g. for residential purposes, also when applying a heat pump.

Another and very large market, and hence demand, is replacement of all existing electrical heating cartridges, which are used in industry for heating of processes and process water. By replacing the conventional electrical heating cartridges with a flameless catalytic heating system according to the invention, it will be possible to change to direct heating using fossil or sustainable fuels and thereby avoid the environmentally very harmful process, involving converting fossil or sustainable fuels to electrical energy, and subsequently using the produced electrical energy for heating process water for heating purposes using an electrical heating cartridge.

The transformation process from fossil fuel to electrical energy implies a loss of up to about 60%, depending on the efficiency of the production of electrical energy and which fuels are being used for the production of the electrical energy. The efficiency transforming fossil or sustainable, hydrocarbon based fuels to heat energy using the present invention is about 110% (by definition, as the flameless catalytic heating unit may be condensing).

Due to the fact that the present invention may work effectively with numerous liquid and gaseous fossil and sustainable fuels, as well as hydrogen, the invention may find use, also in the future. Hydrogen is by many experts believed to play an important part in the future, as it may act as an effective accumulator for electrical energy, since the electrical energy produced by wind or wave energy may be converted to hydrogen using electrolysis. The hydrogen produced by electrolysis may be mixed with natural gas with up to 85% without causing problems, which is the reason why there exists a well-developed distribution system in Europe and USA for hydrogen and natural gas which is mixed with hydrogen.

The present invention may further ensure an improved exploitation of the materials and a lower strain on the materials, while it takes up far less space than corresponding, conventional systems. There may be weight reductions of up to 80% as compared to conventional, modern condensing residential boilers. Catalytic burning is a well tested technology, which has been used for more than 100 years. Only by switching to catalytic burning/reaction it is possible to reduce the emissions of NOx considerably, when burning fossil fuels.

The present invention makes use of the experiences and the properties of a flameless catalytic burning/reaction, which is described in WO 2009/003481. Deliberate use is made of the fact, that catalysis occur in the temperature range of 400 - 800°C. These temperatures correspond to an I wavelength of about 3-10μιτι. This means that the IR radiation emission specter is almost coincidental with the maximum absorption specter of water, which is in the range 3-10μιτι.

The catalytic heating element according to the invention is at least partly surrounded by a medium to be heated. The unit surrounding the catalytic heating element and the cooling zone for the emission gasses are designed to be mounted on all standardized containers, process equipment, pressure containers, throughput units, etc., e.g. by flange connections or replaceable adaptors using a similar principle as used mounting e.g. standardized electrical heating cartridges in similar containers. The material, which separates the catalytic heating element from the medium to be heated, may provide an almost loss free energy transmission of IR radiation as well as convection heat. Materials such as quartz glass, aluminum and copper are examples of suitable materials. A liquid filled space of about 1 - 5 cm around the heating element ensures the IR radiation is effectively absorbed by e.g. water.

The unit which contains the catalytic heating element and the cooling zone may according to an embodiment be obtained by deep drawing or hydro-forming directly in the material surrounding the cavity, which comprises the medium to be heated. Alternatively the catalytic heating element comprising the cooling zone may be mounted e.g. by welding.

The gas and air supply for the catalytic element may occur via a combined transport and distribution pipe, which is concentric and placed in parallel to the catalytic element. This pipe extends from the bottom of the catalytic heating element. In order to ensure a uniform distribution of the gas/air mixture, also in the case of modulating use, the combined transport and distribution pipe is perforated in specific sections.

In order to ensure an effective cooling of the emission gasses from the catalytic burning/reaction, the outer contour of the heating system may be supplied with certain extremities, which ensure an effective cooling of the emission gas during its movement from the area of the catalytic burning/reaction, to the vent manifold. The design and layout of these extremities allow the formed condensate to be drained safely, by a correctly placed draining area in the vent manifold. In order to further ensure the maximum cooling of the emission gasses, a heat exchanger may be established in the area surrounding the vent manifold. The air which is sucked in for use in the catalytic burning/reaction, is led, via the cavity of the outer cover around ventilator and the vent manifold, closely by the vent manifold, which is made in a material having a high heat transmission capability in order to be heated by the emission gasses which is led away from the vent manifold. Thereby the emission temperature is further lowered, and the total efficiency increased, as the collected heat energy is transferred back to the flameless catalytic heating element via the intake air.

Further a concentric, isolating element may be placed around the combined transport and distribution pipe for the gas/air mixture, which ensures that all emission gasses are being led to the extremities, in order to achieve an effective cooling.

The concentric, isolated element may further have at least two additional functions, namely reflecting IR radiation from the catalytic IR burner and thereby impeding IR radiation from heating a cooling zone for the emission gasses and further reduce the heating of the air/gas mixture during its passage to the catalytic IR burner.

By combining the technologies mentioned above and adapting the mechanical design, it is possible to provide an optimally placed and optimal directional heat radiation and heat transmission as compared to a water containing medium for use e.g. for heating and cooling purposes. Another immediate technical effect is a very high energy conversion which may occur with a wider specter of fossil and sustainable energy carriers, to the medium which is being supplied energy in the form of heat, such as, but not limited to, heating of domestic appliances, absorption heat pumps, space and water heating, as well as general process heating.

The high efficiency may be independent of the used fuel, as the heating element is provided with a number of features, which all have the purpose of optimally releasing the chemical energy of the supplied fuel, and accordingly ensure, that the released energy is transferred to the medium which is to be heated with the smallest possible loss, and preferably generating a reduced amount of harmful emissions.

According to an aspect of the invention the following elements may contribute to reaching a high efficiency:

Build-in flameless catalytic I burner which is surrounded by an IR radiation transparent element;

An effective and condensing cooling zone for the emission gasses, having a design ensuring the condensate is effectively collected and drained;

A heat exchanger transmitting the remaining heat energy from the emission gasses to the inlet air; and/or

An isolating and IR reflecting element, having the purpose of ensuring an effective thermal separation between the flameless catalytic IR burner and an optional condensing cooling zone for the emission gasses.

Figures

The figures show embodiments of the invention. The person skilled in the art will realize that elements and features of the embodiments may find general application with the necessary modifications, and the applications are thus not limited to the present embodiments.

Fig. 1 shows a schematic representation of a generic flameless catalytic heating system, which is mounted on a hot water tank, acting as: Accumulation tank for energy collected with a solar collector, hot water tank for domestic hot water (DHW), mounting platform for the flameless catalytic heating system, and a heating source for a water based space heating system.

The depicted application allows maintaining a high comfort level in the habitation with far better economical and environmental benefits, by using renewable energy as supplementary energy source for heating of DHW, process water and heating of houses, using a solar collector in a private house or commercial property, independent of the time of the year and the need for DHW and the demand for heating. The high comfort level may be maintained all year round, without necessarily having a supplementary electrical heating cartridge installed in the hot water tank and a separate boiler placed close to the hot water tank. Fig. 1 shows a flameless catalytic heating system according to the invention (111), mounted on a hot water tank (106) using 2 heating coils, i.e. a heating spiral (107) which via hoses (102) circulates the energy received by the solar collector (101) to the DHW (105), and a heating coil (103) which have dimensions allowing transfer of the necessary energy from the water of the hot water tank (105) to the central heating system (112) of the housing. A flameless catalytic heating system (111) is connected watertight and pressuretight to the hot water tank through a standardized flange (109), allowing the I transparent pipe (108) and the condensing cooling zone for the emission gasses (104) to be completely surrounded of the water in the hot water tank (105). It is an advantage to mount the flameless catalytic heating system (111) as low as possible in the hot water tank (106), thereby obtaining the lowest possible water temperature around the IR transparent pipe (108) and the condensing cooling zone for the emission gasses (104), thereby allowing obtaining a very high efficiency of the total system. The flameless catalytic heating system (101) is provided with a standard adaptor system (not shown), allowing mounting of a standard balanced vent (113). The cold domestic water is supplied through the pipe connection (110) and the domestic hot water, DHW, is drained through the outlet pipe (114).

Figure 2 is a schematic drawing showing a generic flameless catalytic heating system mounted on an absorption cooling element for use in an air based cooling and heating facility for use in domestic housing or commercial premises.

The flow diagram shows an operational situation, wherein there is a need for DHW and removal of heat, e.g. from commercial premises or housing. Note that the DHW is heated with the surplus heat which is pumped away from e.g. commercial premises or housing. This means that the absorption cooling element acts as a heat pump, thus utilizing the surplus energy, which is removed from e.g. housing and commercial premises, for the heating of domestic or process water. The efficiency in this situation is about 60 - 100%.

Due to the fact that the present invention in principle may be mounted directly in and/or integrated in all sorts of containers, in which a heating of the medium is desired, via a standardized flange or similar adaptors, it is also possible to mount a flameless catalytic heating system according to the invention directly in the generator of the absorption cooling element, which is being supplied energy by heating of the working medium, which may be a solution of ammonia and water or alternatively an aqueous solution of lithium bromide.

On Figure 2 such an installation is shown; a flameless catalytic heating system (202) including the balanced vent (203) is mounted on an absorption cooling element (201). Gaseous reaction products (204) escape through the balanced vent (203). The condenser circuit consisting of the pipes (205) and (206) is connected to the condenser (208) as well as the heating coil (213) in the hot water tank (212). The vaporizer (216) is connected to the vaporizer circuit via the pipes (217) and (218). The vaporizer (216) receives heat from the hot air, which is blown through the vaporizer (216), rendering cooled air (215). When the working medium in the absorption cooling element is provided with heat energy, the cooling process will run. If a need for heating of the water in the hot water tank (212) occurs, the valves (207) and (222) will be adjusted by the internal control (not shown), such that the condenser (208) is closed down and the circuit for the heating coil (213) in the hot water tank (212) is opened via the pipes (210) and (220). The heating coil (213) in the hot water tank (212) now acts as condenser, and the energy collected in the vaporizer (216) is transferred via the gas driven absorption cooling element (201) to the hot water tank (212). If a situation occurs in which there is no need to supply heat energy to the hot water tank (212), the valves (207) and (222) are adjusted such that only the condenser (208) is supplied with energy, which by a fan (not shown) is delivered to the environment (209). The condenser (208) may be replaced by an underground hose (not shown). Valves (not shown) would in this installation be adjusted to block the connection between the pipes (217) and (218) and the heating coil (213) in the hot water tank (212). The hot water tank (212) is supplied with cold water via the cold water supply (214). The hot water is drained by the pipeline (211).

Figure 3 is a schematic drawing showing a generic flameless catalytic heating system mounted on an absorption cooling element for use in an air based cooling and heating installation for use in housing and commercial premises.

The flow diagram shows an operational situation, wherein there is a need for DHW and supply of heat, e.g. to commercial premises or housing. Note that the gas heated absorption cooling element acts as a heat pump, as the DHW and the rooms are being supplied energy. The total efficiency in this operational situation is about 140%.

Due to the fact that the present invention according to an aspect may be mounted directly on and/or be integrated in all sorts of containers, in which heating of the medium is desired, via a standardized flange or similar adaptor, it is also possible to mount a flameless catalytic heating system according to the invention directly in the generator of an absorption cooling element or the absorption heat pump, which is being supplied energy by heating of the working medium, which may e.g. be a solution of ammonia and water or alternatively an aqueous solution of lithium bromide.

In the depicted operational situation, in which there is a primary demand for heating rather than for cooling, the control will direct a number of internal valves (not shown), such that a switch of the connections to vaporizer and condenser, respectively, occurs, compared to the settings of Figure 2. This means that the vaporizer (208) in this installation or operational situation acts as an "air to liquid unit" or an underground hose (not shown). This implies that the gas driven absorption cooling element (201) acts as a heat pump, which in this operational situation will draw heat energy out of either the air or the underground, and deliver the collected energy, including the energy which is being delivered via the gas driven absorption cooling element, to the DHW and the rooms, respectively. In figure 3 such an installation is shown, a flameless catalytic heating system (302), including the balanced vent (303), mounted on the generator of an absorption cooling element (301). Gaseous reaction products (304) escapes through the balanced vent (303). The vaporizer circuit consists of the pipes (305) and (306) and the vaporizer (308). The valves (307) and (322) have closed the connection to the heating coil (313) in the hot water tank (312). The condenser (316) is connected to the condenser circuit via the pipes (317) and (318) and the heating coil (313) in the hot water tank (312), and is by valves (not shown) also connected to the condenser circuit. The vaporizer (308), which is placed in the open, receives heat from the surrounding air, which blows through the vaporizer (308), providing cooled air (309) or a cooling of the underground via underground hoses (not shown). When the working medium of the generator of the absorption cooling element receives energy, the cooling process will run. If a need for heating of the water in the hot water tank (312) occurs, the valves will be adjusted, opening for the condenser circuit (317) and (318), such that heat energy is led through the pipes (310, 320) to the heating coil (313) in the hot water tank (312). The heating coil (313) in the hot water tank (312) now acts as a condenser, and the energy collected in the vaporizer (308) is moved via the gas driven absorption cooling element (301) to the hot water tank (312). If a situation occurs, such that there is no need to transfer heat energy from the hot water tank (312), the valves will be adjusted such that only the condenser (316) is receiving energy, which by a fan (not shown) is delivered to the surroundings (315). The hot water tank (312) receives cold water via the cold water supply (314). The hot water is drained by the pipeline (311). In the operational situation described here the heat pump (absorption cooling element (301)) draw heat energy out of either the air or the underground, and deliver the collected energy, including the energy which is provided to the gas driven generator of the absorption cooling element, to the DHW (312) and the heated air, which is blown in, and which heats the rooms (315), respectively.

Figure 4 is a schematic diagram showing a catalytic heating system, which preferably is flameless. The numbers refers to the following elements of Figure 4:

401 = The total heating system

402 = Flameless, catalytic heating zone 403 = Condensing cooling zone for the emission gasses

404 = Heat exchange zone

405 = Vent manifold (Exhaust opening for emissions from the catalytic process)

406 = Intake opening for air for the catalytic process

407 = Counter current heat exchanger surrounding vent manifold

408 = Gas nozzle 409 = Ventilator, which together with the gas nozzle (408) and the applied Control system (410), ensures mixing and transport of the correct air/gas mixture for the flameless catalytic burner (414).

410 = Control system incl. valves

411 = Adaptor/flange for mounting of the heating system for the specific container comprising the medium to be heated

412 = Adaptor/flange for mounting of the heating system for the specific container comprising the medium to be heated

413 = Combined transport and distribution pipe for the air/gas mixture

414 = Flameless, catalytic IR burner

415 = IR transparent element, surrounding the catalytic burner

416 = Condensate drain

417 = Vent manifold

418 = Isolating and IR reflecting element, which separates the flameless catalytic burner and the condensing cooling zone for the emission gasses.

419 = Cooling zone for the emission gasses

420 = Reinforcing pipe for the cooling cells of the cooling zone

421 = Connection flange for a standardized balanced vent

422 = Outer shielding mantle which together with the vent manifold constitute a countercurrent heat exchanger (404) for the hot emission gasses and the cold intake air, respectively.

423 = The liquid medium to be heated is situated in the space formed between the container (not shown) and the transparent element (415), which surrounds the flameless catalytic burner (414).

Figure 4 shows a heating system (401) according to an embodiment of the invention. The heating system (401) comprises a flameless catalytic heating/reaction zone (402) as well as a condensing cooling zone (403). The flameless, catalytic heating zone (402) is surrounded by an IR transparent element (415), which transmits heat radiation, from the flameless, catalytic IR burner (414), out into the medium (423). The heating system (401) comprises an isolating and IR reflecting element (418), which separates the flameless catalytic heating/reaction zone (402) and the condensing cooling zone for the emission gasses (403), as well as a heat exchanger zone (404). In order to ensure an effective drain of the condensate from the condensing cooling zone (403), as well as the vent manifold (417) and the chimney (not shown), a condensate drain (416) is placed in the bottom of the vent manifold (417). The heating system further comprises a mounting flange (421), which may receive a standardized balanced vent (chimney), with build-in supply of fresh air. The heating system (401) may be mounted on any kind of container, which is provided with a flange (412), which matches the standardized flange (411) provided on the present invention. The heating system may be provided with a fan (409), control/valves (410), gas nozzle (408) as well as transport and distribution pipe (413) for the air/gas mixture, which is necessary for converting a specific fuel to heat energy, with the highest possible efficiency, and the lowest possible environmental impact. The flameless catalytic heating system described here may be scalable, e.g. in the effect range of 1 kW to several hundred kW, but not limited to this effect range. Within each effect group, the heating system is modular in the ratio 1:10.

The heating system may be adapted to be mountable on and/or may be integrated in all standardized containers, process machines, pressure containers and/or passage units, etc., via a flange connection (411) or changeable adaptors. The heating system may be adapted to be mountable on and/or may be integrated in all standardized containers, process machines, pressure containers and/or passage units, etc., which comprises the medium to be heated, in principle in the same manner as an electric heating cartridge. The part of a flameless catalytic heating system (401), which is placed on the side of the flange connection (411)/adaptor (not shown), which is not surrounded by the medium (423) to be heated, comprises an inlet (406) for gas air mixture and a vent manifold (417) for the exhaust gas or the reaction products.

Figure 5 shows a cross section through a part of the catalytic heating system, which comprises a condensing cooling zone (501) for emission gasses.

Note that the heating system may be embodied differently from the embodiments of Figure 4 and 5, and a heating system (401) according to the invention may be provided with other adaptor systems than the depicted prescribed and standardized flange (411), whereby the heating system (401) may be inserted and mounted in other applications and in other positions. A major advantage is that this basic design shown in Figure 4 and 5, allows placing air supply and vent on the same geometric surface. This means that a present heating unit (401) may be placed in sites, resembling the sites allowing mounting of a standardized electrical heating cartridge, on the items or containers, in which heating is desired.

Traditional heating systems, which employs some sort of combustion, cannot be placed in a similar manner, due to the fact that do not allow placing air supply and vent on the same geometric surface, without the diameter of the mounting flange is unnecessarily large.

A catalytic I burner is placed in the center of the IR transparent element (415), which is supplied with a balanced amount of gas and air for the process, controlled by the applied Control system and vents (410). In order for the catalytic process to be initiated, it is necessary to heat the catalyst. This is performed in the depicted heating system (401) by a heating element, which is placed around the catalytic IR burner (not shown). The air/gas mixture is led to the catalytic IR burner by the combined transport and distribution pipe (413). The air intake (406) and the exhaust return (405) is performed through a standardized balanced vent, which is mounted on the standardized flange (421). The fan (409) ensures maintaining the necessary excess pressure in the transport and distribution pipe (413), which ensures an even distribution of the gas/air mixture over the surface of the catalytic IR burner

(414), and further ensures that the emission gasses (such as carbon dioxide and water vapor) may overcome the inner resistance in the system, and are pushed through the condensing cooling zone (403) and further out into the vent manifold (417) and up through the chimney (not shown).

The present flameless catalytic heating system (401) may have different geometric shapes, depending on the desired application or efficiency. For example it may comprise or consist of two planar units or of one or more bended or curved units, such as cylindrical units.

It has surprisingly been discovered that the present invention is particularly suitable for reduction of the amount of NOx, particles, and other undesirable emissions. The amount of NOx, particles and other unwanted emissions are in particular dependent on two variables: The surface temperature on the active part of the catalyst and the air supply, i.e. the lambda value compared to the stoichiometric equation.

Achieving an optimal surface temperature on the active part of the catalyst

A flameless IR burner according to an embodiment of the invention (414) is adapted such that the area of the active catalytic surface may vary within wide ranges and still give off radiation heat evenly distributed along the full length of the IR transparent pipe. These properties are important parameters for reducing the creation of N02-CO and particles, as the creation of these emissions is a function of the surface temperature on the active part of the catalyst and the amount of air - the lambda value, depending on the actual fuel. In the depicted embodiment the flameless catalytic IR burner (414) has a basic construction, adapted to comprise from about 5% to about 100% catalytic material, with the same diameter and length, and the same tapered shape, in the curved part of the truncated cone.

Air surplus: Lambda value compared to the stoichiometric equation.

Preliminary work indicates that an about 20% air surplus is necessary as compared to the stoichiometric equation. In order to ensure the desired amount of air, as well as an even distribution of the air/gas mixture independent of the actual fuel and the corresponding optimal amount of air, the combined transport and distribution pipe for the air/gas mixture (413) is constructed to allow the curved part of the surface of the combined transport and distribution pipe for the air/gas mixture, which is contained in the flameless catalytic IR burner (414) without further change of details, to comprise perforation patterns, which are divided in as many perforated segments (e.g. 4) along the length axis, as there are arranged catalytic elements each stretching in the direction along the flameless catalytic IR burners surface (e.g. 4). This means that a complete burner, which is easy to replace, consisting of the elements (413) and (414), may be optimized for each single fuel, such as the fuels mentioned in the present patent application. Note that the combined transport and distribution pipe for the air/gas mixture (414) and the flameless catalytic I burner (413) may be turned with respect to each other, with the purpose of ensuring that the perforated segments in the combined transport and distribution pipe for the air/gas mixture (414) is positioned optimally with respect to the segments on the flameless catalytic IR burner (413) by a rotation around the respective length axes. The two elements may be maintained in the position which is optimal at any time, e.g. by a mechanical joint (such as a spot welding).

Fig. 6 is a schematic representation of a conventional absorption heat pump wherein an external gas flame (Burner) is used for heating.

Fig. 7 is a schematic representation of an embodiment of an absorption heat pump according to the present invention wherein a Catalytic heating element has replaced the Burner of the prior art. Further, isolation has been added, to reduce energy losses.

Fig. 8 is a schematic representation of a conventional Combi boiler system. This diagram illustrates a simple heating system connected to a combi boiler. No external pump, no tanks, no external expansion vessel, no motorised valves, and item 6 is optional. (An automatic bypass valve is often fitted inside combi boilers).

A combi boiler only requires one flow through water heater. This means that every time a small amount of DHW is needed, the boiler will start producing hot water. This leads to very high energy losses, and a substantial amount of pollution due to poor combustion in a cold boiler.

All cited references are incorporated by reference.

The accompanying Figures and Examples are provided to explain rather than limit the present invention. It will be clear to the person skilled in the art that aspects, embodiments and claims of the present invention may be combined.

Example

In a conventional gas heated absorption heat pump, efficiency comparable with the use of a gas burner to boil water in a pot may be obtained. The heat utilization is about 40-50%. According to an embodiment of the present invention, when a catalytic heating element is incorporated in a heat isolated generator of an absorption heat pump, this corresponds to a catalytic heating element placed in a thermos, providing an efficiency of above 100%.

Increased efficiency implies reduced harmful emissions.

Claims

1. A use of a catalytic heating element to reduce the emissions of C0₂ emerging from using a fluid fuel for heating,

by supplying the fluid fuel and a fluid which comprises oxygen to said catalytic heating element and allowing said fluid fuel and said fluid which comprises oxygen to react in a catalytic reaction; and

by allowing a medium which comprises water to absorb heat energy from the catalytic reaction, transferred as heat radiation and at least one of heat conduction and heat convection, by having said medium at least partly surrounding said catalytic heating element.

2. The use according to claim 1, wherein the heating is used for ultimate heating and/or cooling air for a living space in buildings or means for transportation.

3. The use according to any of the preceding claims, where the fluid which comprises oxygen is air.

A use of a catalytic heating element to reduce the harmful emissions emerging from usin a fluid fuel for heating,

by supplying the fluid fuel and a fluid which comprises oxygen to said catalytic heating element and allowing said fluid fuel and said fluid which comprises oxygen to react in a catalytic reaction,

any by allowing a medium which comprises water to absorb heat energy from the catalytic reaction by heat radiation and at least one of heat conduction and heat convection, by allowing said medium to at least partly surround said catalytic heating element.

5. The use according to claim 4, wherein said harmful emissions is NOx.

6. A use of a catalytic heating element to reduce energy losses emerging from using a fluid fuel for heating, by supplying the fluid fuel and a fluid which comprises oxygen to said catalytic heating element and allowing said fluid fuel and said fluid which comprises oxygen to react in a catalytic reaction; and

by allowing a medium which comprises water to absorb heat energy from the catalytic reaction by heat radiation and at least one of heat conduction and heat convection, by allowing said medium to at least partly surround said catalytic heating element.

7. A method for lowering harmful emissions upon use of a combustible fluid for heating, said method comprising:

Using a catalytic heating element to heat a medium, said catalytic heating element being at least partly surrounded by said medium, allowing a combustible fluid to react with oxygen in a substantially flameless reaction.

8. The method according to claim 7, wherein said harmful emissions are selected among C0₂ emissions and NOx emissions.

9. The method or use according to any of the preceding claims, wherein said medium is contained in a tank, said tank being selected among a tank for a solar heating system, a tank for a generator in an absorption heat pump, a tank for a combination condensing boiler, and a tank for a condensing boiler.

10. The method or use according to any of the preceding claims, wherein the heating is for heating space, such as housing, domestic or commercial premises, or a car, such as an electrical car.

The method or use according to any of the preceding claims, wherein said combustible fluid is selected among hydrogen and fossil fuel.

12. The method or use according to any of the preceding claims, wherein said medium

comprises water.

13. A water tank heating system comprising: A water tank;

A solar heating system connected to said water tank, for heating the water of said water tank;

A heating system or unit comprising a catalytic heating element, said catalytic heating element being immersed in the water of said water tank, allowing heating the water of the water tank with a combustible fluid.

14. The water tank heating system according to claim 13, wherein said catalytic heating element is positioned in the lower half of said water tank, preferably in the lower third of said water tank.

15. A combination condensing boiler comprising:

A water tank; and

A catalytic heating element, optionally as part of a heating system or unit, said catalytic heating element being immersed in the water of said water tank, allowing heating the water of the water tank with a combustible fluid.

16. The water tank of any of the claims 13 - 15, wherein part of said catalytic heating element is made of quartz, allowing I radiation to pass through the quartz, thereby heating the water.

17. An absorption heat pump for space heating comprising a catalytic heating element.

18. The absorption heat pump according to claim 17, further comprising a generator having a water tank, wherein said catalytic heating element is situated in said water tank of said generator.

19. A heating system (401) for flameless catalytic heating of a medium, said heating system allowing catalytic reaction, said heating system comprising:

A housing with an inlet (408) for a combustible fluid, inlet (406) for a fluid, said fluid containing oxygen, and outlet (405) for the reaction products from the catalytic reaction; A countercurrent exchange zone (404) having a heat conducting wall in the housing, said countercurrent exchange zone (404) being in fluid communication with at least one inlet and outlet, said heat conducting wall partitioning inlet and outlet, allowing heat exchange through said heat conducting wall between, on one side, added combustible fluid and/or fluid which contains oxygen, and on the other side, the reaction products; said

countercurrent exchange zone (404) preferably being thermally isolated from the medium, which is being heated, by a thermally isolating wall;

A heating unit, said heating unit comprising:

A chamber (415) having a chamber wall, at least part of said chamber wall being made from a substantially I transparent material, and at least part of said chamber wall allowing thermal conduction of heat to the medium, which is being heated,

said chamber wall surrounding a catalytic burning zone (402) and a cooling zone (403);

said countercurrent exchange zone (404), burning zone (402) and cooling zone (403) being in fluid communication, allowing fluids to pass from inlet, through the countercurrent exchange zone (404) to the burning zone (402), further to the cooling zone (403), and back through the countercurrent exchange zone (404) to the outlet;

said catalytic burning zone (402) comprising a catalytic burner (414), allowing combustible fluid and the fluid which contains oxygen to react, forming reaction products, preferably by a flameless, catalytic reaction.

20. The heating system according to claim 19, wherein said cooling zone (403) comprises cooling cells (419) for the reaction products, whereby the cooling zone allows

condensation of the reaction products.

21. The heating system according to claim 20, wherein said cooling zone (403) further

comprises a thermally isolating and preferably IR-reflecting element (418) for thermal separation of the catalytic burner (414) and the cooling cells (419).

22. The heating system according to any of the claims 19 - 21, for heating a medium in a

container, said heating system further comprising means, such as a flanged joint (411) or an adaptor, allowing fixation of said heating system to said container comprising the medium which is heated.

23. The heating system according to any of the claims 19 - 22, for heating a medium in a container, said heating system being shaped such that a single opening in the container is sufficient to allow installation of said heating system and subsequently heating the medium.

24. The heating system according to any of the claims 19 - 23, for heating a medium in a container having a wall, said heating system being shaped such that the wall of the chamber (415) may constitute a part of the wall of the container.

25. The heating system according to any of the claims 19 - 24, for heating a medium in a container, the container being a hot water tank, a pipe or a counter flow water heater.

26. The heating system according to any of the claims 19 - 25, wherein the cooling zone (403) is placed such that the cooling zone (403) is in contact with the medium, which is heated, preferably between the flange (411) and the catalytic burning zone (402).

27. The heating system according to any of the claims 19 - 26, wherein the part of the

chamber (415), which surrounds the cooling zone (403), is shaped as cooling fins, form cooling cells (419).

28. The heating system according to claim 27, wherein the shape of the cooling fins (419) allows a formed condensate to be captured and lead to an independent outlet for draining, preferably in a condensation drain (416).

29. The heating system according to any of the claims 19 - 28, further comprising a

counterflow heat exchanger (407) in the area around the external side of an exhaust manifold (417) and the internal side of an external cover (422), allowing heat exchange between reaction products and supplied fluids.

30. The heating system according to any of the claims 19 - 29, further comprising a combined transport and distribution pipe (413), allowing supply of fluids to the catalytic burner (414) to be conducted by said combined transport and distribution pipe (413), which is concentrically placed and in parallel with respect to the catalytic burner (414), said transport and distribution pipe (413) extending to the bottom of the catalytic burner (414).

31. The heating system according to any of the claims 19 - 30, wherein the medium, which is heated, is a fluid, preferably a liquid, more preferred a liquid which contains water, preferably water.

32. The heating system according to any of the claims 19 - 31, wherein the wall of the

chamber (415) is made in a material transparent with respect to infrared radiation, which is impervious to fluid for immersion in liquids, preferably a material selected among aluminum, copper, and quarts, or mixtures or alloys comprising any of these materials.

33. A heating unit for heating a medium with a combustible fluid and a fluid which contains oxygen, said heating unit comprising:

said chamber wall surrounding a catalytic burning zone (402) and a cooling zone (403); said burning zone (402) and cooling zone (403) being in fluid communication, allowing fluids to pass from the burning zone (402) to the cooling zone (403);

34. The heating unit according to claim 33, wherein said cooling zone (403) comprises cooling cells (419) for the reaction products, whereby the cooling zone (403) allows condensation of the reaction products.

35. The heating unit according to claim 34, wherein said cooling zone (403) further comprises a thermally isolating and preferably IR-reflecting element (418) for thermal separation of the catalytic burner (414) and the cooling cells (419).

36. A use of the heating system or the heating unit according to any of the claims 19 - 35, for heating water in an apparatus selected among an immersion heater, a hot water tank, a dishwasher and a washing machine.

37. A method for heating a liquid in a container, said liquid preferably comprising water, using a heating system or a heating element according to any of the claims 19 - 36, said method comprising surrounding said heating element at least partly with the liquid, providing a space filled with liquid of at least 1 cm, preferably 2 cm, more preferred at least 3 cm, preferably 4 cm, more preferred at least 5 cm, from the part of the surface of the chamber, which is I transparent, to the surrounding container.

38. A method for heating of a medium, preferably water, by catalytic, preferably flameless, combustion of a gas, said gas comprising methane, wherein said catalytic reaction is conducted at a temperature of at least 500°C, more preferred at least 600°C, preferably at least 700°C, more preferred at least 750°C, preferably around 800°C, in a container, wherein at least part of said container is made of an IR transparent material, preferably a material selected among aluminum, copper, quartz, or mixtures or alloys comprising any of these materials.

39. The method according to claim 38, wherein the site of said catalytic reaction takes place is at least partly surrounded by said medium.