Condensation trap/moisture removal ???

[skyhuck]

How about a lascom data logger on the input and output, this with a sample log which you can weigh during the cycle and you would have good empirical evidence of efficiency.

 

Sorry you've lost me there I've tried googling "lascom data logger", but got no where.

 

I get what you mean about weighing a sample log, thats a great idea and something I will start doing

[openspaceman]

Sorry you've lost me there I've tried googling "lascom data logger", but got no where.

 

Sorry Skyhuck, I got the name wrong, senility setting in as another year of my life passes by

 

EL-USB-2 | Data Loggers

 

Depending on how the flow goes in the kiln you can either log temperature and RH either side of the pile or just treat the kiln as a black box and log air in (before heat recovery), kiln temperature and air out (which is probably a surrogate for kiln temperature. From this you can calculate the increase in moisture to the air from the wood. The check log should be split in half and one half microwaved (carefully) to get the oven dry weight and hence the original moisture content. If mixed species you may need more than one. From this you can calculate when the check log is dried to a given mc. I write date and time plus mass on the log with indelible ink and do an excel sheet later.

 

The same things can check the efficiency of heat recovery.

[Scotty38]

Don't know yet, its only been running for just under a week. It gets real hot, feels like sauna.

 

I need to get a thermometer in there and a moisture meter to check how fast the logs are loosing water.

 

Just a question for my curiosity but how much timber do you dry at a time and roughly how long would you expect it to be in there?

Also what do you use as fuel to run the kiln? I'm assuming wood but not sure....

[Hodge]

Just a question for my curiosity but how much timber do you dry at a time and roughly how long would you expect it to be in there?

 

Also what do you use as fuel to run the kiln? I'm assuming wood but not sure....

 

 

Tell us more about your set up huck as it sounds interesting:)

[Dean Lofthouse]

For the moisture to condense you need to introduce a cold surface. I would remove the insulation from the end of the container, in this weather the wall would then act as a condenser and the moisture would run down it to the floor. You could put in a little trough to catch the moisture and drill a small hole to drain outside. ?

 

You'd use a little more energy but it would remove moisture quite efficiently, especially if you increase the surface area of the wall

[Scotty38]

Tell us more about your set up huck as it sounds interesting:)

 

Not sure why you needed to quote me so assuming that was sarcasm for some reason..

[openspaceman]

For the moisture to condense you need to introduce a cold surface.

 

Yes you need to cool the saturated air below the dewpoint.

 

I would remove the insulation from the end of the container, in this weather the wall would then act as a condenser and the moisture would run down it to the floor.

 

 

Yes but the reason is that all the heat of the condensing water is being lost to the wall plus the difference in temperature of the kiln is also driving heat through the uninsulated wall.

 

To be efficient the kiln needs to draw dry air in, heat it up so it can absorb even more water and then dump it outside at as near ambient temperature as possible.

With a dehumidifier you form a cold surface onto which the condensate settle and dumps its heat of vaporisation into the refrigerant which is then compressed back into a liquid at a higher temperature than the kiln, i.e. it gives the heat back into the kiln at the cost of electricity to run the device.

 

The alternative means, as I suggested and Renewable John, uses, is to suck in a small amount of cold dry air and pass this via a heat exchanger in contraflow with warm saturated air leaving the container, so the only heat (apart from losses through the insulation) leaving the system is in the vapour in the saturated air dumped outside.

 

Now your bare wall idea could form a cheap heat exchange surface if the insulation was replaced against the inside surface of the wall with a small gap but closed at the bottom with a row of holes to the outside at the bottom .With a similar arrangement for the outside but holes into the container at the top with a channel at the top into the container to prevent the internal flows short circuiting. It would work by the small portion of the circulation in the container being bled down the wall and then vented outside to waste with a drain for condensed water. The incoming cold air would be sucked up the wall and gradually pick up heat from the wall until it entered the main circulation warm and dry.

 

This would be for a recirculating system, straight through systems can also be efficient but more suited to lower temperatures.

[Hodge]

Not sure why you needed to quote me so assuming that was sarcasm for some reason..

 

 

Not at all I want to know more about his kiln, I quoted you as you asked some questions and I was interested.

[skyhuck]

Just a question for my curiosity but how much timber do you dry at a time and roughly how long would you expect it to be in there?

Also what do you use as fuel to run the kiln? I'm assuming wood but not sure....

 

The container is 35ft long, but there is a movable insulated partition that can be used to shorten the internal area being heated. I'm using a 90KW wood gasification boiler to run the 30KW blower, this boiler also heats my home.

 

I'm only just started to play with it, so don't know how long it will take to dry different sized loads.

[richardwale]

Sounds very interesting. So what type of wood do u feed the boiler? Does it really have to be 20% or less or can you be a big less picky? Will it take chip as well? Cheers