Windhager BioWIN260 with wood pellet feed system and 3 Ton hopper (Waldo county - Maine)

[jebatty]

Ew, what's your point? I answered heaterman's long post on cost giving what I thought was more accurate analysis. If you're able to do better, please do so. If I made mistakes, please correct. The comment "then do so correctly" is in your court, as you evidence a belief that my info was not correct. I will be more than happy to learn from your expertise, from which I have learned many times in the past.

 

[heaterman]

One of the things that struck me with pellets was the difference in flue gas dew point vs wood. Even nicely dried and seasoned wood.

The Testo 330-2 that I use for flue gas measurements allows me to select moisture content of the Biomass/wood being burned. After dialing the appropriate number into the meter it will tell me what the dew point of the flue gas is and that is a big clue as to how some of these advanced pellet burners get the efficiency numbers that they do.
For example; earlier this year I was fiddling with my son's Econoburn wood boiler and had tested his mixed hard maple and oak at between 18-23% MC. Nice dry wood. As I remember, the flue gas dew point shown was in the 200-220* range. which makes sense seeing that most wood boiler manufacturers recommend minimum water temps in the 140-150 range.
When I dial in 10%MC for testing a pellet boiler the flue gas dew point on the Testo reads in the low 100* range. Usually around 106-118*. Just looked at the one I have burning and the flue temp is running about 20* above water temp. This is pretty consistent when the burner is modulated below 100% output. The water temp set point is 165* and it varies around that to about 172*. The flue gas temp was 189* which would normally be near catastrophic for a wood burner. The flue would be dripping.
In the pellet boiler however, the Testo says that the flue gas dew point is currently 108.6 so there is plenty of margin to avoid condensation even at only 15-20* difference between flue gas and water temperature.
This has some to do with the design of the boiler and it's ability to wring nearly all the energy out of the flue gasses but for the most part it is simply a function of extremely dry fuel so there is no moisture to contend with.

 

[heaterman]

BTW our dear Government's own Energy Information Agency is where I came up with the 8250 btu/pound for pellets. It's the number they use on the Excel spread sheet for comparing net fuel costs for different fuels.

 

[jebatty]

Btu/lb gets very confusing, as some sites use "gross" heating value, others use "net" heating value, others use HHV (high heat value) and yet others LHV (low heat value). And then there are sites that come up with btu/lb for which I cannot find a rational explanation. The Forest Products Laboratory, USDA, USFS has this explanation which helps in part: (broken link removed)

The higher heating value (HHV) of a fuel is the amount of energy available from its complete combustion, including the energy from condensing the water vapor that results from the combustion. The lower heating value (LHV) is the HHV minus the energy from condensing the water vapor that results from the combustion. All fuels generate some water from hydrogen during the combustion process; this also results in a lower heating value.

I'm not aware that "complete" combustion can be obtained anywhere but in a laboratory, as I think it must take place in the presence of pure oxygen.

 

[Downeast Farmer]

Would you have that efficiency on a well-modulated burn? What I'm really asking is this: is there any point to having storage with this?

 

[scooby074]

I think it's informative.

I do too!

 

[heaterman]

Would you have that efficiency on a well-modulated burn? What I'm really asking is this: is there any point to having storage with this?

I would in certain scenarios. The primary one being where a person is using a coil in a forced air system which of course is an all or nothing type demand. While a pellet boiler can come up to temp and shut down much more quickly than a wood fired boiler, it's still not instant on/off.

Even a hot water baseboard system could go from full demand to nothing and create problems.

I've been watching the one I have burning here today and it is about a perfect match for my type of system. Only one of my zones is baseboard with a zone valve. There are 5 panel rads with TRV's and the radiant floor is constant circ with an outdoor sensor controlled mixing valve modulating temp to that. There are only two pumps and they are both constant circ. No traditional thermostats in the house.It is proportional control.
The pellet boiler has been running between 30 and 60% firing rate ever since I flipped it on yesterday. No off cycles so the ideal would be to have some type of constant
demand type system.

 

[Downeast Farmer]

It seems there's no way out of using storage with a fan coil in a forced air system, unless you have a minimum temperature you're always circulating through the fan coil. By "proportional control" you mean in proportion to the outdoor sensor?

 

[PassionForFire&Water]

It seems there's no way out of using storage with a fan coil in a forced air system, unless you have a minimum temperature you're always circulating through the fan coil. By "proportional control" you mean in proportion to the outdoor sensor?

I don't see any difference between a water based or air based system. Heat is heat

The BioWIN will just modulate between 100% and 30% of the heat load.

We have a test setup in the shop with a BioWIN100 and a 35,000 BTU/hr water-to-air HX for training purposes
The BioWIN100 pellet boiler just modulates.

If the water-to-air HX is under-sized to the capacity of the pellet boiler, then it will modulate.
If the water-to-air HX is over-sized to the capacity of the pellet boiler, then it will run at max output.

 

[Downeast Farmer]

So, Marc--
Scenario 1: radiant heat, constant circulation, pellet boiler always on but modulating between (in Heaterman's example) 30% and 60%.

Scenario 2: fan coil heat exchanger, which cycles on and off in response to T-stat, which in turns cycles the pellet boiler on and off.

Isn't Scenario 2 bad for the boiler? I thought cycling caused premature decline.

 

[PassionForFire&Water]

I would in certain scenarios. The primary one being where a person is using a coil in a forced air system which of course is an all or nothing type demand. While a pellet boiler can come up to temp and shut down much more quickly than a wood fired boiler, it's still not instant on/off.

Even a hot water baseboard system could go from full demand to nothing and create problems.

I've been watching the one I have burning here today and it is about a perfect match for my type of system. Only one of my zones is baseboard with a zone valve. There are 5 panel rads with TRV's and the radiant floor is constant circ with an outdoor sensor controlled mixing valve modulating temp to that. There are only two pumps and they are both constant circ. No traditional thermostats in the house.It is proportional control.
The pellet boiler has been running between 30 and 60% firing rate ever since I flipped it on yesterday. No off cycles so the ideal would be to have some type of constant
demand type system.

The manufacturer Windhager specifically tells you not to use water storage.
Only for the BioWIN100 installed in a situation where the heat load is less then 3 kW they suggest a small water storage.
I will need to look up the volume they recommend.

Also, all installations require a time delay of 10 minutes when heat demand stops.
This is to drain all the heat out of the boiler and bring it to where it is needed: in the rooms.
This again tells you they do not want water storage.

Windhager did extensive testing, and to them, water storage is a loss of energy and there for a loss of efficiency for a modulating pellet boiler.

 

[PassionForFire&Water]

So, Marc--
Scenario 1: radiant heat, constant circulation, pellet boiler always on but modulating between (in Heaterman's example) 30% and 60%.

Scenario 2: fan coil heat exchanger, which cycles on and off in response to T-stat, which in turns cycles the pellet boiler on and off.

Isn't Scenario 2 bad for the boiler? I thought cycling caused premature decline.

It's my opinion that correct sizing of both pellet boiler and W2AHX will prevent the on/off situation.

We have one setup where a 1000 SF shop space is heated with an W2AHX via a BioWIN260, besides baseboard in the main house.
Will ask the home owner how this works out for him
I will get back to you.

 

[Downeast Farmer]

Also: Is there a way to incorporate solar panels into a Windhager system. Compare with, for example, the Bio-Sol furnace, which has a pellet burner into a 630-liter tank with heat exchangers, a real slick way of incorporating solar (or the heated water from the wood cookstove). How would you do this with a Windhager?

 

[PassionForFire&Water]

Also: Is there a way to incorporate solar panels into a Windhager system. Compare with, for example, the Bio-Sol furnace, which has a pellet burner into a 630-liter tank with heat exchangers, a real slick way of incorporating solar (or the heated water from the wood cookstove). How would you do this with a Windhager?

630L = 170 gallons
What is the purpose of this setup? DHW or space heating?

 

[Downeast Farmer]

see http://www.lakelandrenewables.com/lakeland-renewables-swebo-energy-details37ab.html?id=59

The system outputs heat and DHW and accepts pellet burner or solar (or whatever) as inputs into, essentially, a central "energy cell."

If one wanted to use the Windhager as an input for an energy cell, the cell is really just thermal storage. Into the storage goes the heat exchanger from the Windhager and the heat exchanger from the Solar; out from the storage goes DHW and space heating.

I gather if you can't use storage with a Windhager, you couldn't do it this way. Is there some other way you'd incorporate solar into your system?

 

[heaterman]

I can see where Windhagers opinion is coming from after watching the 260 we have running on the installation we did in the 6400 sq ft building we did the first of December. The only "mass" that boiler see's when the radiant floor quits calling for heat is the 100 or so feet of pex running between the boiler location and the primary loop. Maybe only 4-5 gallons of water including the primary loop itself.
The boiler is able to shut down very quickly once heat demand stops and just sit there and maintain set point temperature.

That particular application shows a cycle ratio of 1 start/stop for every 1.16 hours. If we could let the boiler go completely off rather than maintain the set point the ratio would be even higher. As it is, the boiler is sitting in an unheated but insulated small building erected where the old OWB stood. So rather than running a thermostat wire from the heated space to call the pellet boiler on/off we had to simply jump the terminals to create a constant "demand" as keep the boiler warm. The underground loop circulates through the primary inside the building constantly. If I could have designed the system from the start it's not the way I would have done it. As it is a retrofit installation though, we have to work with what is there and I have to say it works pretty well all things considered.

 

[heaterman]

see http://www.lakelandrenewables.com/lakeland-renewables-swebo-energy-details37ab.html?id=59

The system outputs heat and DHW and accepts pellet burner or solar (or whatever) as inputs into, essentially, a central "energy cell."

If one wanted to use the Windhager as an input for an energy cell, the cell is really just thermal storage. Into the storage goes the heat exchanger from the Windhager and the heat exchanger from the Solar; out from the storage goes DHW and space heating.

I gather if you can't use storage with a Windhager, you couldn't do it this way. Is there some other way you'd incorporate solar into your system?

I have seen exactly what you describe on Windhagers website and think that such a system is common in Europe. They use a large storage tank with multiple coils in it to allow for inputs/outputs from/to varying heat sources. The manual I have even talks about integrating the pellet boiler into a system already served by a cord wood boiler and having them work together. Maybe I'm wrong but the way it reads it appears that if both boilers are Windhager, they can be "connected" and will communicate with each other.

 

[PassionForFire&Water]

see http://www.lakelandrenewables.com/lakeland-renewables-swebo-energy-details37ab.html?id=59

The system outputs heat and DHW and accepts pellet burner or solar (or whatever) as inputs into, essentially, a central "energy cell."

If one wanted to use the Windhager as an input for an energy cell, the cell is really just thermal storage. Into the storage goes the heat exchanger from the Windhager and the heat exchanger from the Solar; out from the storage goes DHW and space heating.

I gather if you can't use storage with a Windhager, you couldn't do it this way. Is there some other way you'd incorporate solar into your system?

I will have a look at this later this week.

But again, it's all about proper system design, doesn't matter the brand or air or water as an energy carrier. (I'm not in favor of air applications, but they have there place in the heating world)
What's your goal and how you will get to it.

 

[Downeast Farmer]

I have seen exactly what you describe on Windhagers website and think that such a system is common in Europe. They use a large storage tank with multiple coils in it to allow for inputs from varying heat sources. The manual I have even talks about integrating the pellet boiler into a system already served by a cord wood boiler and having them work together. Maybe I'm wrong but the way it reads it appears that if both boilers are Windhager, they can be "connected" and will communicate with each other.

This may be a good system for this place. In would go boiler, solar, cookstove hx, out would go DHW (now done by cookstove but to excess) and heat. Are they doing pressurized storage with multiple hx's (similar to the Bio-Sol), or unpressurized?

 

[PassionForFire&Water]

I have seen exactly what you describe on Windhagers website and think that such a system is common in Europe. They use a large storage tank with multiple coils in it to allow for inputs/outputs from/to varying heat sources. The manual I have even talks about integrating the pellet boiler into a system already served by a cord wood boiler and having them work together. Maybe I'm wrong but the way it reads it appears that if both boilers are Windhager, they can be "connected" and will communicate with each other.

Yes, but you will need the Windhager controller to so.
And this is not available yet in North America

 

[PassionForFire&Water]

I'm getting addicted to this forum.
I need to get to work

 

[Downeast Farmer]

That particular application shows a cycle ratio of 1 start/stop for every 1.16 hours. If we could let the boiler go completely off rather than maintain the set point the ratio would be even higher. As it is, the boiler is sitting in an unheated but insulated small building erected where the old OWB stood. So rather than running a thermostat wire from the heated space to call the pellet boiler on/off we had to simply jump the terminals to create a constant "demand" as keep the boiler warm. The underground loop circulates through the primary inside the building constantly.

So the analogous fan coil system would have the boiler constantly circulating through the coil to keep the boiler warm?

 

[heaterman]

It seems there's no way out of using storage with a fan coil in a forced air system, unless you have a minimum temperature you're always circulating through the fan coil. By "proportional control" you mean in proportion to the outdoor sensor?

Proportional control means that the system itself is able to respond not by initiating an on/off cycle but rather by varying either temperature or flow rate to match the heat loss of the building under changing demand.
In my case, the TRV's on each of the radiators "throttle" the flow rate as the room temperature changes while the radiant floor part of the system changes the actual water temperature in response to outdoor temperature.

Proportional control of a heating system is like cruise control on your car. The heat output is not on/off but rather , is able to change output based on demand.

 

[Downeast Farmer]

Proportional control of a heating system is like cruise control on your car. The heat output is not on/off but rather , is able to change output based on demand.

I think I finally understand this! Thanks.

 

[heaterman]

I think I finally understand this! Thanks.

Proportional control on the output side of the system eliminates a huge number of on/off cycles especially when coupled with an appliance that is able to vary it's output like the pellet boiler we started this discussion with.

The Windhager I am running right now will go from 100% down to 30% and anywhere in between in order to match actual demand. That's the input side of the equation.