Number of Guns at once

[SkiDork]

wow - great explanation Chris. You really know your stuff...

 

[RootDKJ]

Just as an fyi, posts like Chris's and BushMM's are a huge reason why I stay here

You can't get this kind of insiders info anywhere else.

 

[Puck it]

A snow gun that has the capacity of 750gpm is useless and that is why Hedco only sold a few and abandon the idea. In the picture you can see that it is only operating at about 10% of its capacity. The conditions required to convert that much water into snow from a single point just does not happen often. The plum will saturate and nucleation will be poor.
Like most things snow-making is situational. If your ski area sees a lot of optimal snow-making conditions then sending more water through individual guns makes sense.
In Connecticut and point even more south we can not depend on optimal conditions so running more guns with less flow to each of them gets us open and it also cuts down on the time it takes to plow trails out.
8 years ago we went to a 100% low –E operation. We get 98 towers and 12 fan guns up and running within 25 minutes of what we determine to be the “go temperature” (early season 28 wet bulb). That covers about 60% of our terrain. This allowed us to equalize and maximize our air water ratio throughout the system. Using100% of available air and water.
Prior to converting to low-E we would run 22-30 air water guns on 10% of our terrain and it would take at least a couple of hours to get them all on line. In this scenario we used 100% of our air and less than 50% of our water. It takes about 3 gallons of water to produce 1 cubic foot of snow. The air is simply part of the production process not part of the finished product.
Back then our normal opening would be one run top to bottom WROD. Now we open with 6 trails wall to wall.
Our low-E guns flow just under 20gpm in marginal snowmaking conditions and can be increased up to 60gpm as conditions improve. They consume between 60-100cfm of air.
Last year we tested a gun that used 5cfm and flowed 44gpm. It was impressive. We did not get to run it until mid January when our water is just above freezing. I will be interested to see how it performs with early season water temps.

Is there a way to control the size of the ice crystal formed with standard guns?

 

[Rambo]

So, Sunday River can convert 9,000 gallons of water per minute into machine made snow - and run 220 snow guns at once.

I would think, Mount Snow, Killington and Hunter have similar capabilities.

 

[BushMogulMaster]

Is there a way to control the size of the ice crystal formed with standard guns?

Standard, as in Air/Water? It depends on the model. Most Low-E guns offer a variety of nozzle sizes, depending on operating temperature. This is great in theory, but difficult in practice (imagine having to change 500 nozzles out just because you want to make snow in warmer temps, or vice versa!)

However, many older a/w guns had no way to adjust droplet size. Different guns were built for different operating temperatures. Some worked better in marginal temps, some worked better at low temps, etc.

 

[BushMogulMaster]

A snow gun that has the capacity of 750gpm is useless and that is why Hedco only sold a few and abandon the idea. In the picture you can see that it is only operating at about 10% of its capacity. The conditions required to convert that much water into snow from a single point just does not happen often. The plum will saturate and nucleation will be poor.
Like most things snow-making is situational. If your ski area sees a lot of optimal snow-making conditions then sending more water through individual guns makes sense.
In Connecticut and point even more south we can not depend on optimal conditions so running more guns with less flow to each of them gets us open and it also cuts down on the time it takes to plow trails out.
8 years ago we went to a 100% low –E operation. We get 98 towers and 12 fan guns up and running within 25 minutes of what we determine to be the “go temperature” (early season 28 wet bulb). That covers about 60% of our terrain. This allowed us to equalize and maximize our air water ratio throughout the system. Using100% of available air and water.
Prior to converting to low-E we would run 22-30 air water guns on 10% of our terrain and it would take at least a couple of hours to get them all on line. In this scenario we used 100% of our air and less than 50% of our water. It takes about 3 gallons of water to produce 1 cubic foot of snow. The air is simply part of the production process not part of the finished product.
Back then our normal opening would be one run top to bottom WROD. Now we open with 6 trails wall to wall.
Our low-E guns flow just under 20gpm in marginal snowmaking conditions and can be increased up to 60gpm as conditions improve. They consume between 60-100cfm of air.
Last year we tested a gun that used 5cfm and flowed 44gpm. It was impressive. We did not get to run it until mid January when our water is just above freezing. I will be interested to see how it performs with early season water temps.

Nice post, Chris.

I'm still not convinced, however, of the actual benefit of Low-E a/w snowmaking. Certainly, in middle-of-the-road temps (teens & low 20s), you probably see some definite savings in terms of air consumption. But at ideal snowmaking temps, standard a/w guns will make a lot more snow with the same amount of air. For example, with a wetbulb of 0 degrees F, you can blow at 180gpm out of a big Rat, and make lots and lots of good snow. You're Low-E gun next to it will probably max out between 40 and 80gpm, depending on the nozzles you're using. And the Rat, at those temps with full water flow, won't be using much air at all! There are exceptions to every rule, of course, but my experience has shown that as the wetbulb temp drops, the value of Low-E guns takes a big turn for the worse!


I do see, however, in the case of a smaller ski area (or a ski area with minimal air capacity, or higher average temps) how you would be able to push more water as a result of using less air per unit. I guess I'm sort of thinking in the hypothetical, where maxing out air isn't a concern, and there are plenty of nights below 10F.

 

[Greg]

Nice post, Chris.

I'm still not convinced, however, of the actual benefit of Low-E a/w snowmaking. Certainly, in middle-of-the-road temps (teens & low 20s), you probably see some definite savings in terms of air consumption. But at ideal snowmaking temps, standard a/w guns will make a lot more snow with the same amount of air. For example, with a wetbulb of 0 degrees F, you can blow at 180gpm out of a big Rat, and make lots and lots of good snow. You're Low-E gun next to it will probably max out between 40 and 80gpm, depending on the nozzles you're using. And the Rat, at those temps with full water flow, won't be using much air at all! There are exceptions to every rule, of course, but my experience has shown that as the wetbulb temp drops, the value of Low-E guns takes a big turn for the worse!


I do see, however, in the case of a smaller ski area (or a ski area with minimal air capacity, or higher average temps) how you would be able to push more water as a result of using less air per unit. I guess I'm sort of thinking in the hypothetical, where maxing out air isn't a concern, and there are plenty of nights below 10F.

Remember. Chris is the ops guy at a hill here in CT so I think he's describing what works best for him. Another good [post="371518"]post by God[/post]....uh....I mean Chris.

 

[bvibert]

Remember. Chris is the ops guy at a hill here in CT so I think he's describing what works best for him. Another good [post="371518"]post by God[/post]....uh....I mean Chris.

Indeed, I'd bet that our conditions are less than ideal for making snow most of the time. That's probably why the low e works good down here.

 

[Puck it]

Standard, as in Air/Water? It depends on the model. Most Low-E guns offer a variety of nozzle sizes, depending on operating temperature. This is great in theory, but difficult in practice (imagine having to change 500 nozzles out just because you want to make snow in warmer temps, or vice versa!)

However, many older a/w guns had no way to adjust droplet size. Different guns were built for different operating temperatures. Some worked better in marginal temps, some worked better at low temps, etc.

Thanks. Do you know what the nozzle sizes are? Would a variable nozzle be beneficial based on temperature and self adjusting?

 

[drjeff]

Nice post, Chris.

I'm still not convinced, however, of the actual benefit of Low-E a/w snowmaking. Certainly, in middle-of-the-road temps (teens & low 20s), you probably see some definite savings in terms of air consumption. But at ideal snowmaking temps, standard a/w guns will make a lot more snow with the same amount of air. For example, with a wetbulb of 0 degrees F, you can blow at 180gpm out of a big Rat, and make lots and lots of good snow. You're Low-E gun next to it will probably max out between 40 and 80gpm, depending on the nozzles you're using. And the Rat, at those temps with full water flow, won't be using much air at all! There are exceptions to every rule, of course, but my experience has shown that as the wetbulb temp drops, the value of Low-E guns takes a big turn for the worse!


I do see, however, in the case of a smaller ski area (or a ski area with minimal air capacity, or higher average temps) how you would be able to push more water as a result of using less air per unit. I guess I'm sort of thinking in the hypothetical, where maxing out air isn't a concern, and there are plenty of nights below 10F.

The low e issue I think has to center around the majority of the conditions when you'll be using them, In the east, a good chunk of snowmaking time occurs in less than ideal snowmaking conditions (i.e. Early season to open and immediately post thaw/freeze to resurface) and in times like that where you're wet bulb is much more likely to be closer to/above 20 than it is to be around 0, and in those key times, you're generally looking to get as many guns running over as much acreage as possible to get the best surface possible for the paying customers. Additionally, the modern phiolsophy of snowmaking at many mountains is to put down 2 to 3 feet of snow on most snowmaking trails and then basically be done making snow on that trail for the year, relying on the skills of guys like yourself in the cat to save the surface after a thaw/freeze up instead of wide spread "top dressing" with some gun time, so having to make a huge quantity of snow over the course of a season isn't as common place as it once was. So the need to/ability to wait for those ideal 0 degree wet bulb temps to make mega amounts of snow with little air isn't as much a factor as it once was in the East. Out West, where you're normally talking dryer air and a lower wet bulb temp then it can be a different story.

Lastly, marketing. "Green" is in, and as we all know, low e=green. Plus, if low e allows an area to make snow on say 2 trails instead of 1, or 4 trails instead of 2, those extra trails lit up with plumes of snow from the guns makes the job of the folks in the marketing dept that much easier

 

[BushMogulMaster]

Thanks. Do you know what the nozzle sizes are? Would a variable nozzle be beneficial based on temperature and self adjusting?

Again, it depends on manufacturer and model. But here's an example:

Ratnik Sky Giant II

Available Nozzles (assumes 400PSI water pressure)

A (55cfm, 16gpm, 20-26 degrees F)
B (55cfm, 31gpm, 16-22 degrees F)
C (55cfm, 38gpm, 12-18 degrees F)
D (55cfm, 56gpm, <14 degrees F)



Because a variable, self-adjusting nozzle would probably require moving parts, it's not very feasible due to freezing issues. The best adjustment for temperature is just controlling how much water you feed the gun. Therein lies the downside to being stuck, for example, with nozzle A when you get a really really cold night. You're still limited to 16gpm, when you could be pushing a lot more than that and making good snow.

 

[BushMogulMaster]

Remember. Chris is the ops guy at a hill here in CT so I think he's describing what works best for him. Another good [post="371518"]post by God[/post]....uh....I mean Chris.

I wasn't questioning or criticizing Chris. On the contrary, if you re-read my post, I admitted that under certain circumstances, Low-E is probably the best solution. But from my experience where I've been involved with snowmaking, I don't particularly care for them, nor am I convinced of their results.

 

[Greg]

I wasn't questioning or criticizing Chris. On the contrary, if you re-read my post, I admitted that under certain circumstances, Low-E is probably the best solution. But from my experience where I've been involved with snowmaking, I don't particularly care for them, nor am I convinced of their results.

Wasn't insinuating anything. Just wanted to clarify... :beer:

 

[BushMogulMaster]

Wasn't insinuating anything. Just wanted to clarify... :beer:

:beer:

 

[Puck it]

Again, it depends on manufacturer and model. But here's an example:

Ratnik Sky Giant II

Available Nozzles (assumes 400PSI water pressure)

A (55cfm, 16gpm, 20-26 degrees F)
B (55cfm, 31gpm, 16-22 degrees F)
C (55cfm, 38gpm, 12-18 degrees F)
D (55cfm, 56gpm, <14 degrees F)



Because a variable, self-adjusting nozzle would probably require moving parts, it's not very feasible due to freezing issues. The best adjustment for temperature is just controlling how much water you feed the gun. Therein lies the downside to being stuck, for example, with nozzle A when you get a really really cold night. You're still limited to 16gpm, when you could be pushing a lot more than that and making good snow.

I have another idea. No moving parts. All I can say right now. Need to document it.

 

[BushMogulMaster]

I have another idea. No moving parts. All I can say right now. Need to document it.

I'll be curious to hear your thoughts, once you're work is protected. Consider, as you scheme, that every low-e gun I've seen is external mix, while many standard a/w guns are internal mix. It changes the entire nozzle philosophy and necessary spray patterns, depending on where the air and water come together. Some guns also employ separate nucleator nozzles which spray even finer droplets which freeze very quickly, and act as nucleators for larger droplets from the other nozzles.

 

[Puck it]

I'll be curious to hear your thoughts, once you're work is protected. Consider, as you scheme, that every low-e gun I've seen is external mix, while many standard a/w guns are internal mix. It changes the entire nozzle philosophy and necessary spray patterns, depending on where the air and water come together. Some guns also employ separate nucleator nozzles which spray even finer droplets which freeze very quickly, and act as nucleators for larger droplets from the other nozzles.

Thanks. I will let you know it what I have in mind can be made.

 

[BushMogulMaster]

Thanks. I will let you know it what I have in mind can be made.

 

[Chris Sullivan]

I agree that changing nozzles is too time consuming and cumbersome during snow-making. In our HKD spectrums the front four nozzles that run under standard operation are set up for low flow (20gpm). The two rear nozzles (these are operated by a valve) can increase the flow by 12, 22 or 40grm. The guns are set up in pods of 3 progressing down the hill with a color code to indicate flow rates. At 20 degrees we will open the 12gpms at 14 degrees we will open the 22gpms and below 10degrees the 40’s. This gives us the flexibility to change flow rates without changing nozzles.
I don’t know if I have ever seen zero degrees wet bulb. There have been seasons that we have opened 100% without going below 20degrees.

 

[BushMogulMaster]

I don’t know if I have ever seen zero degrees wet bulb.

Guess that's one of the big differences between Northern New England and Southern New England. We have a fair number of annual nights that approach and/or dip below 0 WB. Makes standard a/w snowmaking very very efficient and extremely productive!

We do, BTW, have plenty of Low-E guns at the Bush. But their effectiveness dwindles in low temps. Not to mention increased sublimation due to smaller droplets...