Clydesdale Newbie

[gdisarcina]

I just had my Clydesdale inspected yesterday, and had my first fire last night. I am new to the insert world and have a couple of questions.

When should I throw another log in the box, when the ones in there all get down to coals? I am afraid to overstuff the box, and want to get the proper burn/heat output.

Should I have the blower on all the time, or will the heat be dispensed without it on?

When going to bed (bed is on 2nd floor, with stove on first), should I keep blower on high, low or off?

Sorry for the basic questions, and if anyone can point me in the direction of a thread that explains all this I would appreciate it.

 

[ClydesdaleBurner]

Congrats on the Clydesdale purchase. Its a nice unit. I'm coming up on my second season with it and I'm really looking forward to getting it going.

Try the advanced search and search by username for Rhonemas and Tuner-n-Burner. They have both written some very detailed and lengthly Clydesdale posts. Very informative.

Here is a pretty good thread for the Clydesdale owners. There are at least a few other threads out there really focused on running the Clydesdale.

https://www.hearth.com/talk/threads/12316/

Also to answer a few of your questions, you can do a reload (usually at least 2 good sized splits up to 5 or so) when you are down to burning coals. See the above thread for directions on how to load... key to make a channel in the middle of the coal pile.

Also as for running the stove at night you will have to do some trial and error for fan speeds. I usually leave mine on medium night and day. Its not too loud and it still puts out plenty of heat.

Happy burning!

 

[Highbeam]

I stuff my hearthstone as full as I can get it without bashing the roof or touching the glass. They're made for this.

 

[gdisarcina]

Thanks. Will wait for all coals and then reload. It seems like a huge box, I am looking forward to cutting down on my oil bill.....

 

[gdisarcina]

With the blower being electric, what happens in the case of a power outage? Will the stove throw off heat without it?

 

[ClydesdaleBurner]

I had that same thought last winter and the answer is yes it will heat the room the stove is in fairly well, however you will definitely not get the effects of heating the whole floor the stove is in. The blower is key in moving the heat across the whole floor or whole house.

But at least you know you can keep some of your house warm without the blower.

 

[SteveT]

With the blower being electric, what happens in the case of a power outage? Will the stove throw off heat without it?

Until fairly recently the blower was an option on the Clydesdale. That seems strange to me. Operation without the blower doesn't seem to provide anywhere near the heat of operation with the blower. But it does indicate that operation without the blower is viable.

From a pure heat transfer perspective the best operation is with the blower speed on high. Adjust it downward only as needed to keep the noise at a comfortable level.

 

[ClydesdaleBurner]

Engine Rep - to you understand thermodynamics??? I don't. I was wondering about the speed of the fan and what was best for optimal heat output. I notice at medium speed the air coming out is ho,t but less of it vs. high speed where there is more air coming out but it definitley seems less hot because the air hasn't had as much time to heat up in the channels around the stove.

Any thoughts on this???

 

[SteveT]

Engine Rep - to you understand thermodynamics??? I don't. I was wondering about the speed of the fan and what was best for optimal heat output. I notice at medium speed the air coming out is ho,t but less of it vs. high speed where there is more air coming out but it definitely seems less hot because the air hasn't had as much time to heat up in the channels around the stove.

Any thoughts on this???

I'll be glad to take a shot at it. First, your observation is correct. With less air flow (slower fan speed) you will be getting air at higher temperature but less of it. However, the total energy (heat) getting into the house is going to be higher with lower air temperature and greater air flow. There are two issues to consider.

First and most important is the conductive heat transfer, i.e., getting the heat from the firebox to the walls of the insert. The three factors that drive that is the surface area (square feet), the thermal conductivity (K factor) and the temperature differential between where you have heat and the colder surrounding area the (the delta T). The calculation involves multiplying these three factors to determine the total heat transfer. Since the first two are fixed for the stove the only factor that can be controlled is the delta T. The firebox temperature is fixed (at any point in time depending on how the burn is being controlled) so maximizing the delta T maximizes the heat transfer to the wall of the stove. The most efficient way to maximize the delta T is to run the blower at a higher speed; doing this lowers the surface temperature of the stove's wall (evidenced by the lower air temperature you feel). You are increasing the heat transfer to the stove wall and allowing less heat up the flue.

By the way, this "delta T calculation" is exactly the phenomenon that explains why you use more fuel as it gets colder outside... the delta T between your house and the outside air increases so heat transfer increases. And it is also why degree-day calculations work - the relationship is linear. So assume you keep your house at 70 degrees. If you use 1 unit of fuel/day when it is 60 degrees outside you will use 2 units/day when it is 50 degrees, 3 units/day at 40 degrees, etc.

The next consideration is the heat transferred by the air itself. Here the elements are how much air (CFM), a constant (Cp) and the delta T. With the blower you vary CFM and, as a result, delta T (they are inversely related). Again, assume the house temperature is 70 degrees. You get the exact same heat transfer blowing 200 CFM at 170 degrees (delta T = 100) or 100 CFM at 270 degrees (delta T = 200). The key is that the higher CFM equates to a lower air temperature, which you observed. But the lower air temperature is entirely compensated by the greater CFM since the efficiency of the air channels is fixed by the design and will not vary over the normal operating range. (And your observation that it has to do with the air not having enough time to warm up is also spot on. Heat exchanger designers spend a lot of time optimizing fin configurations to control contact time. But that is a design consideration, not an operating consideration. Over the operating range of a stove blower the efficiency will be a constant).

There are limits to this of course. If you have ever used a heat pump on a cold day you have observed that a flood of air at mildly elevated temperature doesn't feel nearly as good as lower flow and higher temperatures. But within the limits of a stove blower even the coldest air is hot. So go for the maximum blower speed you are comfortable hearing and you will extract the most BTU's.

And finally running the blower at high speed does not use more electricity (at least on the Clydesdale). Speed control is by a rheostat so electricity used is constant; what electricity doesn't get to the blower is released as heat at the rheostat.

 

[Bill]

EnginRep thank you for that excellent response, I have had these same concerns on my mind. I often read that a blower on a wood stove (not an insert) doesn't really matter. Then it would also make sense that a ceiling fan may help spread the heat evenly over a given area, but does not substitute as a stove blower.