6 Comments

1. The entire time I was reading this blog I was surprised that this idea/ control scheme is not something that is already on the market today, because it seems like such a great idea! I can see this feature being of great interest to consumers all over the US and Canada. Especially, when you are offering a product that can save people money, I think that is always an attractive offer. All in all, I was impressed by how through you were with explaining all of the possible considerations for disturbance variables and ways in which one might go about controlling them to make the system function more efficiently. I especially liked that you were not stuck on the idea of solely melting the snow for removal, but pondered upon the idea of altering the surface properties of the panel itself to aid in the removal of snow/ ice.
   The proposal scheme is logical and fairly intuitive, making it easy for all consumers to understand, which I think is great, but I do have a few questions about specific features. Firstly, if the system is programmed to melt snow, how will it deal with ice? The proposed method talked about weighing the snow and in turn having a controller that altered the heat supplied based on the weight measured, but if an equal mass of ice and snow were present on the panel, wouldn’t it take more heat to melt the ice, and if so how may your system deal with identifying this variability? Additionally, I would like to pose that perhaps a 5th sensor be added in the center of the panel, I think it would provide a more robust and accurate weight measurement to your system. Also, if the panel was able to heat in sections rather than the entire system at once this may allow for the saving of money/ energy and also add a redundancy feature if for some reason the pitch alone does not cause all of the snow to fall off, this may help to target the problem area.
   The implementation of a feature such as this in world of solar panels, does not seem far off, but I am concerned the pricing model that you proposed. I understand that you would save $100 a panel, but how many panels does an average household have on their property? The only metric you supplied seems like a far stretch from the average user, especially since you are saying that the target market is residential households. If a house only has a few panels and I would imagine this technology would add upfront, capital cost to the purchase, would it truly be a worthwhile ROI for the consumers?
   Overall, the idea is a great one and I am impressed by the forecasting you provided with what this product as the potential to be if more of the disturbance variables could be controlled. I am also not sure if you guys designed your own logo and the process diagram, but if so I think it is so fun and creative! Nice job!

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2. You guys did a really great job presenting this concept in an engaging and accessible way. I think it’s actually a good thing that I was left with some questions because it means that you have some great concepts that made me think.

   Ideally, I think it would be true that “the proposed snow melting device and process control would go a long way to solving this problem, making solar panels in the northern regions of the United States and Canada much more profitable and economical,” but wouldn’t a cost-benefit analysis be required before saying anything certain about profit? How do you know for certain it’s a worthwhile financial investment? Some information about approximately how much energy or money is wasted during snow-covered months would be helpful here. Also, you say in the beginning that “every year snow covers the majority of the United States for some period of time,” but is this true? If so, cite it. You address this a little later in the post, but it would make more sense earlier as justification.

   Other questions I have include whether this application will even be relevant in the next 20 (or 50) years due to climate change. Have you proven mathematically that the force of gravity is sufficient to slide the snow off the solar panel regardless of the angle of the panel? What if the panel were horizontal? Would that ever be the case? If the target audience is the general population, you need to make sure that the 100$ lifetime savings is worth the investment. Would these solar panels be significantly more expensive than regular ones? If so, is saving 100$ (over multiple years) worth paying the up-front cost? These considerations may make such a product less realistic to implement and less marketable. You later say that solar farms are better-suited as customers, so why would you initially say that the target audience is the general population? Are you integrating both feedback and feedforward control?

   Also, you do have some minor grammatical errors, such as “toward” rather than “towards,” parenthesis that weren’t closed, “work-in-progress,” not “work-in progress,” etc.

   Overall, I think this is a cool application and is definitely conceptually very interesting, although I wonder about its practicality. I especially love the idea of having a hydrophobic coating, which would address some of the concerns I raised previously about whether the angle and gravity would be sufficient.

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3. Guys I must say this a great idea, and it’s clear that it been in the works since spring semester in Germany. I think you guys struck bulls eye on number of points here that are great for such an application- first, it has to do with renewable energy, an emerging market, and second, its purpose is to save people money, which is one of the last things holding back renewable energy from taking off.
   As far as the control scheme is concerned, it makes sense that you’d implement a weight sensor, since your target market could experience heavy snowfall, but to that point-you didn’t include just how much weight would trigger the system, or just how sensitive the sensors are. Why is relevant? Well even the slightest covering of snow would essentially reflect all incoming light to the panel (being white and all). This could be a millimeter thick layer, which would not weight a significant amount, and would possibly be blown away by wind soon enough anyway. Would such a situation elicit a response from your system? I propose instead a different mechanism, where possibly the panel emits some kind of radiation, and if the radiation is reflected by snow on the panel, it is redetected, and that triggers the heating mechanism, or something along that lines. My point is, snow can sometimes have densities as low as even .1 grams per cubic centimeter, 10% that of water.
   Now let’s talk about the heat. Gentlemen, heat is very expensive. So it’s worthwhile to consider, how much heat would I need? How much would the heat cost? Can my battery even provide that heat? Will I need an insanely large battery to provide that heat? How much would that battery cost? Recall that you have to first raise the heat of this snow from god knows how much below zero degrees up to zero first, and then overcome the latent heat of fusion. That’s a lot of energy, and this isn’t even pure ice. Snow has a lot of air in-between it, which does not conduct heat properly, so you end up having to add even more heat to overcome this. And we all know solar battery technology is still in its infancy, so the ability of the panel to recharge that battery is already suspect.
   One final point I want to make: how does the repeated heating and cooling affect the lifespan of the panel? Solar panels are delicate stuff, and I just thought it would be nice to know how subjecting the panel to such heat would affect the integrity of the material.
   All in all, great job guys, I think you’re really on to something here. I hope my comments were useful, and I just ask that if you do find the useful, offer me a reduced share price at the Olympus Energy’s initial public offering.

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4. This blog was extremely well written and explained. As I was reading, almost every question I had ended up being addressed later in the blog. I think that this device definitely has a use, but I’m not sure how practical it would be for residential properties. It was stated that the savings per lifetime of one solar panel would be approximately $100. If a house only has 15 solar panels, they would save $1500 total, but how much would this device cost to install on each solar panel? Or if the solar panel companies are installing it onto their solar panels before selling them, would the price per solar panel go up by a large amount? Basically my question is: would the savings for having Snowmelt outweigh the costs of purchasing or installing it by enough that people would consider it a worthwhile investment? I read your attached calculations and I could only find the cost of the weight sensors factored in, not the rest of the SnowMelt technology, when calculating profits. Also, I missed your attachment the first two times reading your article, since the hyperlink was by itself without any introduction. I would suggest really highlighting these calculations so that readers will click on them. They are a great addition to this blog.

   I appreciate how much detail was put into the disturbance variables section especially, but also the control scheme in general. I really liked the idea of having four weight sensors so that if a bird lands or a branch falls on one of the solar panels it will not incessantly heat for no reason. There are many disturbance variables and you have created solutions for each of them, but having so many disturbances makes solving the problems more complicated and expensive. I’m not saying that it cannot be done, but I think that a more explicit statement of each of the disturbance variables and their solutions would be helpful in understanding the scope of this project.

   The savings section seems a bit out of place to me. Originally, you stated that this would mostly be for solar panel companies selling to residential properties, but in this section, you compare the savings to a solar panel farm in Colorado. You had stated earlier that farms may not have a use for this product because many of them have rotating mechanisms that solve the snow accumulation problem. I think it would be more valuable to use statistics for residential households instead, since they are your target audience, or change your audience to both residential households and solar farms.

   Overall, I would say that this blog has all of the necessary pieces and is well-written, just some of the information doesn’t line up. I would like to see a general estimation of how expensive it would be to implement all of the controls to counteract the disturbances. I think this is a great idea for the right audience, as it would make solar panels more efficient in snowy environments.

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5. This is an impressive idea. It’s surprising that this is not already commercially available, since it seems like this has the potential to significantly increase the power generated by solar cells in the winter. I think it is particularly clever to take advantage of solar cells’ inclined position to force the snow to slide right off once it accumulates, rather than taking another more wasteful approach like melting the snow as it hits the panel.

   It seems like you guys put a lot of thought into the potential disturbances that cause the Snowmelt to fail, like implementing multiple weight sensors to ensure that the coating on the panel is actually snow, and setting the Snowmelt up on a timer so that it does not waste energy melting snow at night. Some follow-up questions to consider: If the heater is coupled with the time of day as a way of monitoring day/night, how does this account for changing sunrise/set times with changing seasons? Perhaps some software could account for this. Could heavy rain trigger the weight sensors? The force of the rainfall would likely be evenly distributed across the panel. What about leaves or other solid debris? You could wind up not only wasting energy heating the leaves, but potentially burning them and damaging the panels as well. Maybe add a constraint that the heater turns off at a temperature like 5 oC. Also, I can foresee issues particularly in the early Spring, when it might snow overnight and reach 60 oF by noon, in which case it might actually be beneficial to leave the Snowmelt off; but I guess they pay engineers to make these decisions. Something else to consider: if snow is falling heavily and consistently for hours on end, it might be beneficial to leave the Snowmelt off until the storm passes, as snow storms come with considerable cloud cover. Would it be possible for the Snowmelt to detect the weight of snow on the panel, as well as the rate of weight increase on the panel? If so, it might be advantageous for the Snowmelt to heat the panel only when the weight is significant, but the rate of weight increase is not.

   As far as practical stuff goes, it seems that your target consumers would be those who are looking to set up their first solar panels. Would there be any way to manipulate existing solar panels to incorporate Snowmelt technology? Or does it have to be implemented in new panels specifically designed for Snowmelt? What percent of solar energy is lost when it has to penetrate a layer of snow? Is it 100%? If it’s close to 100%, this could be an appealing stat for potential buyers. Also, for residential applications, could there be issues dumping a large mass of snow somewhere on the property? It might be problematic to drop a ton of snow into the driveway after an overnight snowfall, but I suppose this is more of an installation consideration. You’d probably also want to offer an estimate of the up-front cost of the Snowmelt (software and all) to make sure it could be profitable for the buyer.

   You guys have clearly put a ton of thought into this, and the calculations supplement really makes your cost arguments convincing. You’ve demonstrated that there is both a need and a market for the Snowmelt, and with answers to some of the additional considerations presented, I think this could be a highly marketable idea. I’ve suggested a lot of things, since I think this could be a really useful product that puts Olympus Energy on the map 😉

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6. This blog article presents a very novel application of process control in a clear and detailed way. The design really impressed me with how much it would make our lives better; I can imagine myself using the service if possible! The writers did a great job advertising their design after explaining the basic concepts and underlying principles, and the calculations performed give customers a clear and convincing response to their most possible concerns, i.e., how much economic sense does this service make to me. In addition to an approachable and lucid writing style, part What could happen to our system and part further considerations part both surprised me with the careful considerations of the various disturbances and other details by the team.
   Speaking of the control scheme, the selection of the controlled and manipulated variables are reasonable enough. Logically this design could manage to control the amount snow to the set value zero.
   Problems come when we evaluate the actual benefits that this design could bring us. Though detailed calculations are provided to prove that ‘the average solar panel in Denver, Colorado would save around $100 throughout it’s lifespan’, I think some part of the design deserves to be given further thought. First, just as mentioned in the article, the currently popular scheme to take advantage of solar energy during snow days is ‘rotating mechanisms that could prevent snow accumulation’. We learn from thermodynamics, and can actually do calculations to find out, that generally speaking, making changes in internal energy is much more difficult than making changes in mechanical energy. For example, a hair dryer costs about 50-120 watts in low heat mode, but 1200-1800 watts in high heat mode (this is a daily life scenario, in which the heat produced and air flow created are intuitively comparable, but our goal is to dry hair so low heat mode costs much more time). This design here is dealing with ice, which means that much more energy would be needed to melt the ice than just mechanically remove the ice. The lifespan money saving for average solar panel, in my opinion, would be significantly greater if the rotating mechanisms are explored in details first. This design used in the industrial world could definitely tells us something.
   Second, there are few cases in the article that confuse me. For example, in the what could happen to our system? part, it is written ‘the temperature of the outside air (directly impacting snow density and the chemical potential of solid water)’. I think it is probably intended to be ‘potential energy’ instead of ‘chemical potential’, as the latter is concerned when there is a chemical reaction. In addition, I don’t feel confused when reading that 4 multiple sensors in each corner of the panel to assess if the weight is evenly distributed. I think, this kind of design really costs a lot as sensors are not economically wise to use all the time. Actually I don’t think it’s necessary to monitor that, I mean, the solar panels we are using nowadays don’t even care about this.
   Overall, this is a good design being aware that we are just students studying process control though some problems need to be addressed to make it truly applicable in reality.

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