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Sorry - your browser does not allow this image to be loaded - please download the offline website to view Welcome to FHT Stoves!
A new way to integrate wood burning stoves into your home heating
system, control comfort, save money and reduce your carbon emissions

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FHT Stove Schematic
See below for a description of operation

The FHT Stove:

- Connects wood burning and multi-fuel stoves directly to central heating circuits
- At the flick of a switch half the stove heat can be transferred to the central heating circuit
- User chooses when/if they want heat to be transferred to the central heating circuit
- Unique control of stove heat output to maintain room comfort
- No 'back boiler', no 'heat sink' radiators, no expensive 'link up' equipment
- Disperses excess heat to other parts of the home
- Reduces fuel consumption in the central heating boiler, saves money and reduces carbon footprint
- Maintains high firebox combustion temperatures for clean-burn operation even when transferring heat to the central heating system
FHT Stoves has re-invented the wood burning stove for the 21st century! Although much loved and often desired to control fuel bills and provide heat security, solid-fuel stoves have changed little over the last 100 years. Despite improvements in efficiency and clean burning, stoves have limited control ranges before the 'draw' of the fire becomes too poor resulting in inefficient operation, dirty burning, tarring of the chimney and 'sooting' of the glass. Where the burning rate control range is deliberately restricted to ensure clean burning (such as DEFRA approved stoves for smoke controlled regions in the UK) the customer often finds that the heat output to the room is too much so that the stove can only be lit on the coldest days.

The FHT Stove technology addresses all of the above problems and much more. The FHT Stove connects wood burning and multi-fuel stoves directly to hydronic central heating circuits (water filled radiators) and/or immersion tanks or thermal stores. The user can choose when to transfer around half of the stove heat output to the central heating circuit at the flick of a switch, or choose to have all of the stove heat passing to the room. When the user chooses to transfer heat to the central heating circuit, the output to the room is halved almost instantly so providing a unique level of comfort control which is unobtainable with any other stove technology. When excess heat is transferred to the central heating circuit, this disperses heat to other parts of the house and reduces the consumption of gas or oil in the main system so saving money and reducing the carbon emissions (when burning wood).

The operation of the FHT Stove technology is described in detail below. Other pages on this website give further information about intellectual property and potential configurations of the FHT Stove technology in the home.

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Operation of the FHT Stove

- Fan 'on' - half the stove heat goes to the central heating circuit

- Fan 'off' - all the stove heat passes to the room

The FHT Stove technology is designed to work with convector type stoves. Convector stoves typically output around half the fire heat radiantly from the front of the stove and half as warmed air from slots in the top of an outer cover surrounding the firebox. The proportions of radiant and convective heat can vary by stove design. Convector stoves come in many different sizes and styles ranging from traditional to more contemporary.

The schematic to the left shows a simple convector stove in which the firebox is surrounded by an outer cover. The FHT components (Fan Heat Transfer) can be seen below the firebox and are shown separately in the 'exploded' view below the stove. These consist of a fin-tube heat exchanger and an electric fan. The fin-tube heat exchanger is similar to a car radiator, but works in reverse by heating water flowing through the heat exchanger with a stream of hot air from the stove surfaces. When 'on' the specially selected low power, low noise fan draws hot air from the stove surfaces through the heat exchanger to transfer heat to the central heating circuit. When the fan is 'off', natural convection draws room air in through the fan and heat exchanger which is then heated on the stove surfaces and passes to the room from the slots in the top of the outer cover. See the 'Fan OFF' diagram below. No combustion gasses pass through the heat exchanger or enter the room.

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Advantages of the FHT Stove

- The FHT Stove technology is fail-safe; if the electricity supply fails, heat simply passes to the room
- The fan can be operated from a room thermostat if desired, and with a water temperature thermostat it can cycle on an off like a central heating boiler
- Designed to operate in parallel with existing central heating systems, both pressurised and open vented, or independent circuits
- High firebox combustion temperatures are maintained whether the fan is on or off, so high efficiency, clean-burning can be achieved
- A 'future proof' technology for transferring heat to hydronic circuits - some technologies may be eliminated by future emission standards resulting from European programmes such as the Ecodesign of Energy Related Products (EuP/ErP)
- As the system works with pumped water circuits, heat can be dispersed anywhere in the rest of the home and 'gravity fed' circuits are not required

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Proving the FHT Stove concept

- More than three years of development around various modified standard convector stove models
- More than 1,000 hours of successful testing, the majority of which has been recorded in detail
- Patents granted in the UK and New Zealand, and European Patent accepted for grant
- Further international patenting in US and Canada
- Prototypes demonstrated to stove manufacturers and other interested parties
- Discussions progressing with manufacturers and investors
- Dedicated test facilities and logging equipment enable detailed testing of the FHT Stove operation
- Technology can also be applied to convector-type inset fires (enclosed fireplaces)

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Comparing the FHT Stove to other systems

So what is the difference between the FHT Stove and traditional 'back boiler' systems? Although the FHT Stove can take the place of a back boiler and save considerable sums of money through low cost installation, this is essentially where the comparison ends! Back boilers cannot be turned on and off, require gravity fed circuits with wide bore piping and dedicated heat loss radiators, are expensive to link to central heating systems and often cannot work with pressurised boilers, and reduce the firebox combustion temperature so that clean burn conditions cannot be attained (therefore cannot be used in smoke controlled regions). Although the FHT Stove was principally designed for comfort and efficiency, for customers who want a back boiler system the FHT Stove is an excellent low cost solution with many more advantages. Sorry - your browser does not allow this image to be loaded

What about back boilers with emergency heat dump coils? Although such systems offer some advantages over traditional back boilers, the user is still faced with expensive plumbing (including the cold water 'dump' circuit), a lack of control over heat output, and they reduce the combustion temperature so that clean burning cannot be attained.

The diagram to the right shows one of the many potential connections that can be made with the FHT Stove technology. See the Connections page for others. In this diagram the stove is shown directly connected into a central heating system. By adding a separate pump to the stove circuit, the FHT Stove works in parallel with the central heating boiler. A non-return valve prevents the central heating system pump from sending water through the stove heat exchanger when the fan is off. When the pump and fan are on, central heating return water is taken through the heat exchanger. In this configuration, the FHT Stove can operate whether the system boiler is on or off. When the system boiler is on, heat from the FHT Stove adds to the boiler heat reducing the boiler fuel burn.

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FHT Stoves is a trading name of KinXerG Limited
Copyright © KinXerG Limited, 2009-2014