Passive Recirculating Dehumidification Wood Kiln

Zero Venting – Patented

If you are venting, you are burning your margins

Traditional kilns operate on a fundamental design flaw: they force you to dump your expensive heat into the sky just to get rid of water vapour. In damp climates, venting draws in cold, humid air that sucks the energy straight out of your chamber, stalling your winter production and cracking your high-value summer timber.

The Lansdowne Kiln is built differently. It is a completely sealed thermal vault that extracts moisture as a liquid through engineered condensers, retaining nearly 100% of your heat energy inside the kiln.

By eliminating vents, you keep your wood cells and fibres wide open for stress-free, core-to-surface drying. The result? Near-zero operating bills, zero emissions, and premium, perfectly flat timber that never suffers from case-hardening or surface checks. Stop fighting the weather—let thermodynamics do the work for you.

Passive low energy wood drying cycle

Heat is supplied to the unique underfloor heating matrix from your chosen source.

Stage 1 – Free Water is drawn out of the voids between the wood fibres.*

Stage 2 – Bound water moves along the wood fibres, evaporating from the end grain.*

Natural convection moves the water to the passive recirculating dehumidifier.

*How Bound Water Regulates Wood Drying – Phys. Rev. Applied 14, 054051 – Published 20 November, 2020

Harnessing powerful forces of nature

Trees have a very efficient Transpiration System to carry the water from the roots to the leaves. Firewood and timber come from the trunk and the branches of the tree. Timber and Firewood have a highly evolved water transport system built in.

The Lansdowne Kiln exploits the natural water transport system by optimising the conditions within the kiln chamber.

This is totally unlike other kilns as it keeps the humidity high.

Moving moisture out of the wood slowly keeps the water transport column intact inside the wood fibres so Lansdowne Wood Kilns are able to operate at a lower temperature, and much more efficiently thus using considerably less energy overall.

Lansdowne Kiln Key Features

Robust build quality and attention to detail
Easy loading and unloading
Harnessing the powerful forces of nature
Fast kiln drying is wasteful
Passive Recirculation Dehumidification
Zero Venting Technology wood kiln

Unique EMC wood moisture measurement capability for remote monitoring of wood moisture content.
Maximum thermal storage capacity balances fluctuations from heat supply
Best in class Solar Thermal Collectors with high efficiency water circulation
Air to water heat pump – operating as sole electrical heat source or solar backup during dull weather
Thermodynamic cycle – working with the laws of physics

Loading and unloading a 20’ Shipping Container

Commonly, firewood is processed directly into IBC cages or wire stillages. These can be lifted into position using a telehandler. Stack one on top of the other, two side by side, four deep making a full load of 16 IBC Cages. There will be some space for bags of kindling inside the doors.

Timber can be stacked and stickered into frames and lifted in using a telehandler.

Fast kiln drying is wasteful

Traditionally powered wood kilns (either biomass kilns or fossil fuel powered) dry wood far too quickly and at far too high temperature for the process to be hydrodynamically efficient.

High temperature (high vapour pressure) at the end grain will dry out the ends of the fibres, stop the wicking process, and lock the water inside the logs. Once the fibre wicking has been blocked, even more energy is needed to force out the remaining moisture using very high temperatures and high ventilation rates.

By ventilating too often these biomass wood kilns waste valuable energy, and burn far too much fuel. Ventilating has a knock on effect of drawing in additional moisture when the ambient humidity is high at the inlet.

Passive Recirculation Dehumidification - Low Energy Kiln Drying

Once the air inside the kiln is warmed moisture evaporates from the wood and it rises away.

The moist air passes through to ducts towards the outside where it comes into contact with the ambient temperature. The cold internal surfaces form dew immediately and the cooler, drier air falls under its own weight like a reverse chimney. The dew drips run downwards and into the drain.

The dried air re-enters to the kiln chamber at the bottom to begin the cycle once more. All unused energy (Enthalpy) in the air is recycled back to the chamber.

Patented Kiln Technology - GB2631489 and WO2025008717A1

UKIPO Patent Granted – GB2631489

Also protected by International Patent WO2025008717A1 see: Google Patent

To understand the process, please play the video below. Rest assured, there is nowhere else that this highly efficient technology is available!

Our starting point is a recycled ISO Shipping Container that is already well sealed and designed to withstand the elements.

We carefully install our insulation covering all internal surfaces to maximise the efficient use of energy. All internal surfaces are clad in robust sheets of steel to stand up to the roughest treatment.

The next step is the key to the Kiln’s success. We install its unique in-floor heating system and a remote monitoring system with Equilibrium Moisture Content prediction technology.

Finally, we attach the heating system of your choice; solar, heat pump or waste heat. The heated water slowly circulates through the floor heating matrix providing a highly efficient and stable environment within the chamber. This is what sets up the passive circulation.

Zero venting technology

The kiln operates without any venting. Moisture is removed by a highly efficient passive condensation dehumidification system. No vent is required.

There is no need to open the chamber whilst it is running!
“If you’re spyin’ you ain’t dryin’!”

Remote monitoring of EMC wood moisture content

The Kiln comes with its own unique Equilibrium Moisture Content monitoring system. Its unique algorithm measures the temperature and humidity in the chamber next to the load and gives a daily prediction of the average moisture content in the load.
Users can view this live on a mobile accessible webpage.

Maximum thermal storage capacity balances out fluctuations from an intermittent heat source

The unique and highly efficient floor matrix heating system holds onto every joule of energy it can, making sure that whatever heat is provided it is used to kiln dry the wood. The floor and load form an enormous thermal store, so it holds its temperature for a long time. This unique feature makes the kiln ideal for intermittent heat sources, where perhaps there is a lot of energy for a few hours and then none for the next 48 hours. The wood kiln drying process will continue throughout that time. All energy is automatically saved away and used to kiln dry the wood.

Best in class Solar Thermal Collectors

If you chose the Solar Kiln option, we make sure that it is capable of collecting heat from the sun in all weather conditions.

Air to water heat pump

If you choose the Electrical Kiln option an air to water heat pump is built in.

If you chose the electrical system as your main heat source or as a backup to when your source of free heat (solar or waste) is not available, the kiln design ensures that the efficiency is maximised.

The heat pump option has up to 4.5X thermodynamic gain, so for each kilowatt of power drawn from the electrical supply, up to 4,5 kW of heat energy is provided to the kiln. Heat Pump technology is ideal for use with the Lansdowne Kiln thermodynamic cycle but it is not possible to use one in a conventional system. This is because a heat pump output is limited to 40°C.

40°C is perfect for the Lansdowne Wood Kiln, but not suitable as an energy source for vented kilns.

If you source your electrical supply using an off peak tariff, the costs are kept low as is the carbon footprint.

Passive Recirculating Dehumidification Wood Kiln Zero Venting – Patented