Mounting Strategies 11.22.2010avwFm87mDz
SUNMAXX SOLAR HOT WATER SOLUTIONS
Well, welcome everyone. Good afternoon, welcome to the SunMaxx Solar webinar series. I’m going to spend the next half an hour talking about various mounting strategies and hopefully some of the information is relevant to what you’re trying to accomplish. As always the chat window is open and I encourage you to send some questions my way and I’ll try my best to answer them as they appear. So, without further ado some of you may be familiar with our webinar series. Each week we try to talk about something different and relative and updated. This particular week I’m going to talk about successful mounting strategies.
Some of you may have seen a similar webinar a month or so ago and it’s similar, but with a few updates. Okay, so I’m going to get right into it. I’ve got a lot of different things to talk about in terms of mounting and every application is a little bit different. There are, you know, flat roofs, flush roof, tilt mount, ridge mount, steep slopes, shallow slopes can mount directly to the rafters on the rail systems. And neither option is better. It’s just everyone has a little bit different preferences.
So, I’m going to try to present to you what SunMaxx has done to help make your job easier and give you the flexibility to install these collectors as you see fit. Okay. So, first of all let me talk for a moment about the new mounting hardware for the TitanPower Plus collector, our engineers have been hard at work and have come up with a very simple and obviously meets and exceeds code in terms of wind and strength requirements. And also, it’s extremely adaptable, very easy to install. I recently installed a system on my own home using the new mounting hardware for the TitanPower Plus and I was extremely happy with how easy it was to put together. Okay.
Now, in terms of a single row of collectors versus two collectors or one collector, or multiple banks, the TitanPower Plus hardware gets assembled either a rail mount or without the rail and then the back legs mount directly to the roof. As you see in this picture, this is a photograph of the installation I did at my house. And I used the rail approach. I mounted the rails directly to the purlins off of some roof hooks, which I’ll show you in just a moment. Once the system was… Once the connect system was installed, the collectors simply sit on the rail system. And mounting the actual collectors took me and two of my friends only about 20 minutes to get all the collectors up on the roof and in place.
So, once all the ground work is done in terms of mounting to the roof and setting the rails in place, putting the collectors is actually the easiest part, okay. It all starts with this roof hook and flashing. Whether you decide to go directly at point of penetration where you mount the feet directly to the roof or you use the rail, this is the first step. There are several different products out there that accomplish the same thing. Our roof hooks are adaptable for either point of penetration as in mounting the collectors directly to the roof or to the rail.
The metal flashing clips sits underneath a shingle by about four inches, so, four inches of it needs to be underneath the row of shingles just above. And then we use these self threading screws to drill directly into the rafter. So, you’re not affixed to a particular rafter placement or position of your collectors, the roof hooks not to the rafters. Once you install a rail then you can slide the collectors to the left or to the right and make it symmetrical. So, these roof hooks have a very high sheer strength and they are aluminum. Now, once you install the flashing there’s absolutely no concern whatsoever for a roof leaking.
In a system that I installed, I’ll go back one slide; you can tell I have a metal roof, okay. Well, what I did was use a small piece of butyl underneath the roof hook between the roof hook and the metal. And then I put a piece of butyl self adhesive butyl, on top of the roof hook. So I flashed on top of the metal and I am 100% confident for the life of this system that I will never have any roof leaks as bulk of my roofing skills, right. I know that using this roof hook with flashing will guarantee that there’s not going to be any leakage in my system. Okay.
One of the next steps is the connection rail. Now, the rails are threaded to accept these Allen bolts. Okay, see the Allen bolt, those thread directly into the rail. So, once I install the rail anywhere along the roof hooks, and I have to space the roof hooks out four feet center on center. Okay, so I don’t want to put the roof hooks any more than four feet apart. The strength of the rail allows for displacement weight over four feet, but no more. Okay. So, the Allen bolts will thread directly into the rail as seen in the clip on the left.
And on the right is the clip that attaches the collector to the rail. Okay, so the photo on the left is attaching the rail to the roof hook and the photo on the right is the clip that helps you attach the collector to the rail. Both of them use the self threaded Allen bolts that will thread directly into the rail, which makes it very easy and quick to install. Okay. It is a metric Allen and if memory serves me it’s nine millimeters. However, a small Allen wrench comes with your system. So, if you don’t have the Allen wrench you will have one included and shipped out to you in a little baggie. Okay. Now, in terms of creating back legs for these, there’s two pieces. Basically, one is the vertical support leg, which is made of the same rail or extrusion as the rail. So, some simple “L” brackets will connect the vertical rail to the horizontal rail and then the back leg.
Now, in my case, I went with, what you see here is the hardware for a flat roof or a flat mounting install. In other words you’re either mounting them on the ground or in a flat roof. Okay, so I went with a flat roof, although my roof was not flat, I simply cut the back legs. Alright, so some simple trigonometry, which your sales rep can help you with or it’s also in our technical manual. Based on the roof pitch you will cut the back legs to achieve the desired angle, okay and then, obviously the “L” bracket on the bottom of the back leg will just slide up in the extrusion and mount directly to the rail.
Okay, for long banks and collectors you have to union rails together. Okay, so there’s two rails that you’re going to use. One is the extrusion rail that mounts directly to the roof hooks, on the left. And those rail unions, along with their Allen bolts, will thread directly into the rail creating nice tight union between two rails, displacing the weight, hopefully. And on the right a “T” profile rail. Now, I’ll show you later on what a “T” profile does. That is basically the seat for the collectors. So, the “T” profile will mount to the rail and then the collectors will sit in the “T” profile and there’s small bolts that will thread into those slots that you see on the “T” profile gives at its strength. Here’s an up close picture of the “L” brackets that mount directly to the rail. Okay. So, what you’re seeing here is the vertical rail that the collectors lay onto.
The “L” brackets then will mount directly to the horizontal rail that you’ve attached to the roof hook. Okay and this is all using the same Allen bolts. There’s a couple that are a different lengths, but they’re all labeled appropriately in your packaging. On the picture on the right you also see a clip. Now, that tension clip is going to accept the “T” profile. So, it makes it very adaptable by being able to adjust the back legs and front legs, to the left or to the right on the rail means they don’t necessarily need to measure exactly the length of my rail ‘cause I have flexibility laterally and as well as flexibility vertically in terms of distance because those little clips will slide up or down the rail, depending where you want your collector to be mounted.
So, it makes it extremely versatile and adaptable, but also there’s a lot of wiggle room in terms of making exact penetrations into the roof. It’s not critical. There’s a lot of room for errors so to speak. We don’t particularly encourage error, but we do encourage efficiency. And this allows you to mount your collectors, err, mount your roof hooks in places where, you know, you’re going to get the tightest connection and then you have flexibility in terms of where your collectors mount relative to the roof hook. Alright, in this picture what you see is a TitanPower Plus flush mount. Now, you notice there’s two roof hooks on the bottom and two roof hooks on the top.
So, that’s consistent with the recommendations that we make in terms of the number of roof hooks it is required per flat plate collector. Okay. Your sales rep will be sure to design your mounting system depending on what your considerations are. So, all that you need to know is will you put one or two collectors in series. And do you want flush mount or tilt mount? Once our sales rep has that information they’ll make sure that you have all the correct components included. Now, we do recommend that the roof hooks are placed in the middle of each adjoining collector. Okay, so whether you have two collectors or one collector it’s still going to require a total of four roof penetrations. So, four roof hooks, four flashings.
Now, this is showing the tilt mount hardware. Okay, now the tilt mount would require three points of penetration as opposed to the flush mount. Flush mount tends to be less expensive because there are less components required. It’s also much easier to install. And I would like to make this recommendation now because it’s appropriate that if you have a roof that’s within 20 to 30 degrees pitch of what is the recommended, that the flat plate and the evacuated tube collectors will still perform within about five percent of their expected performance. So, when considering whether to do a flush mount as in this picture here, versus a tilt mount off the roof the to be added benefit to achieving that proper angle is really quite minimal.
So, it’s important to consider obviously performance, but equally important, and in some cases even more important, it is to consider aesthetics, okay. So, I highly encourage you to consider flush mounting your collectors whenever possible. Flush mounting is going to be easier to install. It’s going to require less components and the performance sacrifices are going to be minimal. To be sure your sales rep will be happy to run a report at the various angles that you’re looking to make your installation. Okay, so again, if you have a roof pitch that is within 20 to 30 degrees of what the optimum pitch should be for your collectors you may consider just simply doing a flush mount rather than tilt mount, for three reasons, aesthetics, cost and installation time, which obviously, saves money as well.
Okay, here’s another picture of the tilt mount using a rail system. Okay, now with the rail you accomplish obviously, weight disbursement, but more importantly you’re not fixed to rafter location relative to where your collectors are. And so, often, the back legs of collectors do not line up perfectly with the rafters. So, by using the rail system you can mount your roof hooks wherever your rafters are and then move your collectors laterally depending on where you’d like to see them sit on your roof, whether it’s aesthetics or performance, you have lateral movement on the rail whereas you would not have lateral movement with point of penetration mounting that is the back legs mounted directly to the roof.
There are some exceptions to that, which I’ll cover in a minute, but generally you want to mount to the rafters. Okay, now here’s a tilt mount without using the rail. So, as I mentioned these points of penetration really should be at the location of the rafter. Okay, if you don’t find a rafter then we’re going to have to have access to these points of penetration underneath the roof. And we’re going to have to use toggle bolt or we’re going to have to use a spanner between the rafters, something that secures this entire collector bank to the roofing system rather than just the decking. This is even more important with flat plate collectors than with evacuated tubes, that you have your collector system mounted to the roof rather than mounted to the decking.
And when I say roof, I’m talking about the structural components, that is the rafters or the trusses. Okay, so with flat plates you have a considerable amount of lift, a consistent and considerable amount of lift, on this roof system, especially if your collectors obviously, are facing to the south or in the southeast that means the back of your collectors would be facing to the southwest or the northwest where a lot of the prevailing winds come from. So, it’s important that you secure your collector system to the structural members of the roof and not just the decking. Okay, this is accomplished using a rail versus point of penetration.
Okay, now in terms of roof penetrations, obviously you want to make sure that you don’t have to go back, and when you use a flashing materials such as the one shown here, this is PV quick mount that we used to use and I think it’s a very good product, you’re going to ensure that there is no roof leaking. When you do use these penetrations such as roof hook from SunMaxx or a quick mount PV, those ballasts, so to speak, should not exceed more than 48 inches apart. Okay, so if you have the wrong run, say of 10, 12, 20 feet or more, you’re going to have to use multiple rails. And I did show some connections that can be made to union the rails together to maintain a consistent strength.
It’s also recommended that you pre-drill holes into your rafters, ¼ inch holes. In terms of rafter screws, we recommend that you use a three inch high sheer strength screw and that it be self threading, right, or that you pre-drill the hole. In terms of mounting these ballasts to purlins, for example, if the purlin is just an inch and a half material on its side then a three inch screw may not give you the support that you need. So, you know, you have that inch on the top of the screw where there’s no threads at all. So, you want to make sure that you know what you’re going to be screwing into and that the majority of your threads on the screw are holding the material that you are tying into.
Okay, so if you do order the roof hooks from SunMaxx, you will get three inch screws, which is going to be suitable for rafter mounts, but if you did mount to purlins, for example, like I did, I had to replace my three inch screws, I went with shorter inch and ¾ screws to be sure my threads are mounted to my purlin. Now, there’s several different ways to mount to a roof. Five of which I mentioned here. This spanner method is where you have access to the rafters and below then you create a spanner between the rafters that you can mount your penetrations directly to the spanner. And this sort of serves the same purpose as mounting with a rail.
It gives you horizontal flexibility to move back and forth and you’re not fixed to the location of your rafters. Another one is a lag bolt using flashing. Okay, the lag bolt, like I mentioned, should be at least three inches that’s going to all you to bolt directly to your rafters. Toggle bolts work. They are a little bit more cumbersome to work with and it works well if you have access to the roof below. The toggle bolt should be pretty big with a washer. Some guys are using a piece of plywood as a washer, so they’re using a four inch disk of plywood that acts as the washer for the toggle bolt and I do recommend that as well. “J” bolts have been used quite often in mounting to roofs.
And basically, if you’re going to use a “J” bolt, you are fixed to the location of the rafter and you also need to have access to the rafter itself so that you know exactly where to drill and the “J” can then hook on to the bottom of the rafter. A pitch pan is one of the older methods that’s still being in use. Basically, you mount your lag bolt in through a pan that has a hole in the bottom that’s going to be filled with tar. So, it basically prevents any water penetration. Okay, mounting to rafters as you see here, the “J” bolt and the lag bolt detailed, “J” bolts are being used for, consistently for, but like I said, if you’re fixed to the location of the rafter, if you’re going to use a “J” bolt.
As with the lag bolt, although with a lag bolt you can also mount in the case of metal loops, you can mount to the purlins if the purlins are made of a material that’s at least 2 x 4 inches. Okay. Using evacuated tubes, our hardware is universal, which is very important for those of you who are doing both tubes and flat plates. The hardware is interchangeable for either style collector. Okay, and as I mentioned, no matter what you should not exceed more than 48 inches between your standoffs. Okay, now flat plate flush mount, I think is probably the most aesthetically appealing system. Not to mention, as I said before, it’s the least expensive. It’s simplest to install, but in the end it looks very, very good.
So, this roof being only at about a 35 degree slope would normally be situated at a 55 degree pitch for heating and I do remember running a report at 35 degrees versus 55 degrees and this client is sacrificing only about 7% of the total system outcome, total system output year round too, but mounting it flush rather than having it tilt mount. So, if you did a double bank of collectors, such as the one here with the tilt mount, there’d be a fairly extensive system supporting those collectors off of the roof and gaining only about 7% total output. Okay, so it is a very important consideration to make and understand what losses you’re going to incur if you go the flush mount versus tilt mount.
Here’s an example of mounting the “T” profile directly to the roof. And I’ll show you a photo in just a minute of how the “T” profiles mount to the collectors, but those little clips that you see there, those tension clips, can be mounted either to a hanger bolt as you see in that photo or the tension clips can be mounted directly to the rail. Okay, so all of our components, as I said, are interchangeable and adaptable for just about any roof style. Okay the “T” profile, when used with the hanger bolt, is going to mount directly to the “T” profile and then your “T” profile, as you can see here, mounts directly to the collector. You see the bolt being inserted through the slot of the “T” profile and that connects directly to the stainless steel frame of the collectors.
So, there’s no other components required once the “T” profile is installed on the roof. It makes for a very simple installation especially for flush mounting. Okay, and this is what the final product looks like when you use a “T” profile connected directly to the collector and then the “T” profiles connected to the clip, which is connected to a hanger bolt, which is bolted directly into a rafter with a piece of flashing, okay. And that is a done deal, guaranteed not to leak for the life of the system. Now, there’s several different strategies I want to go over now just in terms of using your vacuum heat pipes and increasing your performance.
Underneath the collectors with a highly reflective roof surface, you can boost performance of these collectors and I’ve seen actual performance numbers increase anywhere from 20 to 30 percent, depending on the type of reflective surface. So, when you’re installing the evacuated tube system, which I know that a lot of you are, it’s very important that you increase the reflectivity behind those collectors. Now, this is something you can suggest to the homeowner or that you can include as part of the system installation, but nevertheless you can guarantee that your system will perform better for the life of the system by increasing the reflectivity behind the vacuum heat pipes.
And I would also point out that there’s a highly reflective roof coating that Sherwin Williams makes for $35.00 a gallon that can be painted directly on metal or asphalt shingles. So, I highly recommend looking at increased reflectivity. In terms of some different types of mounting there’s, you know, ridge mount as with the one that you see on the right. This client, his house was facing 90 degrees in the wrong direction, so he decided to do a ridge mount. I would caution you that making this system mounted perpendicular to the plane of the house does really destruct the aesthetic appeal, if that’s consideration. And the added benefit in terms of performance from 90 degrees off of ideal may only be in the neighborhood of 20 to 25 percent increase performance.
Okay, so you have to consider, very carefully, before you mount to a ridge, is it worth it. And check with your SunMaxx rep. Ask them to do a report at the various azimuth angles and then you’ll know exactly what value you’re going to sacrifice by mounting it along the same slope as the house. Moveable rays are not recommended, but they are possible. The reason they’re not recommended is because you have piping then instead of forming electrons you’re forming pressurized fluid, which tends to try to escape. And so the more often you move your array the more likely you’re going to have some leakage. And knowing that your sacrifices in performance are not nearly those sacrifices that you’ll see in PV systems, it’s not recommended that you design a moveable system.
Okay, now in terms of ground mounting, a lot of systems, a lot of guys who really like the ground mount because they’re easily accessible, they’re easy to clean, any maintenance problems and they’re also not subject to the particular angle of inclination and orientation of the house. They can be put offsite somewhere. We usually recommend that these systems not be installed more than 150 feet away from the house because once you exceed 150 feet you begin to experience a tremendous amount pressure drop, which means bigger pump and perhaps bigger piping and bigger piping is going to mean more losses. Okay, so a general rule about the ground mounting is that you not put these mounts more than 150 feet from the house.
Now, ground mounts can be pretty difficult, but in cases where it’s the only option it is certainly not impossible to put a collector just about anywhere you want. In this particular system that was recently commissioned near Cooperstown, New York, the installer chose to use a cleared approach to the collectors. So rather than having them manifold to manifold to manifold, with brass unions, they are union together, but with flexible ConnectMax piping. Okay, so small sections are used to join one collector to the next. There’s a little bit more added cost for installation, obviously digging the holes and pouring the concrete, but the homeowner had a nice suitable location on a hillside, and you can pretty much guarantee that they are at the proper orientation and proper inclination.
Okay, so ground mounting on flat ground and also underneath ground is very doable. It just needs to be well thought out. Mounting collectors on a flat roof is important to know that the evacuated tubes have very little wind load. And if you notice the picture here on the left these collectors are mounted just through these concrete blocks that are setting on the roof and in the picture on the right these evacuator tube collectors are used for shading for a carport. So, flat roof mounting is very easily done and often does not even have to penetrate the roof in order to accomplish that. Here’s another example of ridge mounting where the back legs of the collectors are straddling the ridge, still facing the same direction as the house. So, we’re not perpendicular to the ridge, but we are ridge mounting it by straddling the ridge.
Okay, another flat roof install one important thing I’d like to point out in terms of flat roof install, particularly in the northern climates, is snow and we recommend that you bring your collector feet off of the roof by at least 12 inches in areas that are prone to snow loads. This will keep your collectors out of the snow, obviously. Allow for movement underneath the collectors, but it’ll act as a snow fence because often, if they’re connected directly to the roof, with no movement underneath, then you’re going to see the collectors work as sort of a snow fence. And there’ll be big piles of snow that trap behind the collectors. So, bring them up at least 12 inches.
Here’s another example where the owner had used the white roofing to increase performance of the collectors. Pole mounts, in the case of, on the right hand side, this single pole mount is actually functioning as a pass through for the supply and return piping as well as the support structure for the collector itself. So, this install was able to get away with a single point of penetration using a steel pole to which he passed a supply and return. The one on the left with the core reflectors, this particular homeowner did not want his collectors on the roof at all. So, the installer was able to accommodate by doing a pole. Obviously, it’s going to raise the cost up considerably. Using concrete standoffs is also recommended particularly for evacuated tubes, ground mounts.
This entire collector field is not mounted to the ground at all. They are simply bolted to these concrete standoffs that act as concrete shoes, for example. And the wind load being less than what the collector weighs, by adding these blocks and bringing them up off the ground, these are off the ground 18 inches as opposed to a foot. So, they’ve exceeded what we recommended, but they’re insuring that there will be no snow buildup on the bottom of the feet. In terms of reducing your summertime production, successful mounting can accomplish that, for example with the one on the left, you see the roof that the collectors are sitting on is acting as a shade for the bottom row reflectors in the summertime.
So, he’s got four collectors total, only two of which are really operational in the summer, and then as the sun drops in the sky the bottom row becomes functional, or façade mounts, like these “U” pipes. Flat plates and evacuated tubes, if you do evacuated tube façade mount it’s got to be direct flow or a “U” type collector. Okay, flat plate collectors can be façade mounted and these are typically used for heating systems where you’re producing excess energy or more energy in the winter and then the production actually drops in the summertime with a perfect 90 degree slope. Overheating in situations where you have access to the collectors, they can be covered up, in a ground mounts not very accessible on the roof, but by having a steep angle, just like the façade mount you can also reduce your production.
Drain back systems need to be mounted at ¼ inch tilt per foot whether it’s a sloped roof like the one you see on the right, or a flat roof as in on the left, all the manifolds need to be mounted at the ¼ inch of slope per foot. Now, ballast systems for collectors can be concrete like this or, pardon me, or they can be a wood ballast and if you do a concrete ballast then you use the hanger bolt. Those hanger bolts that you saw previously that spread directly into the rafter can also be put into concrete and then use the machine threaded to bolt the collector feet together. And then again, there’s your clip with your “T” profile and the collector mounts directly to the “T” profile. Now, here’s a couple of pictures showing the point of penetration with it over the shed.
And then with the green roof this client chose to use the rail system. Okay, the considerations you have to make again are what type of wind load would your collectors be under. Okay, with evacuated tubes you can get away with mounting your collectors to the roof decking with some washers and big washers underneath. So, you’re basically connecting your collectors to the plywood that is then connected to the rafters. Not recommended for flat plates however, because of the wind load. The rail system just makes installation a little bit easier because you’re not fixed to the rafter location you can mount your rails and then mount your collectors and then slide them down as you see fit.
Okay, a couple of important things I’d just like to bring up in terms of mounting strategy considerations. The ConnectMaxx hardware is universal. And so it’s universal in the sense that it mounts to flat plates as well as pitched roof, sloped roof, ridge mount, façade mount, cantilever, rail system versus not rail system. There’s virtually no roof that this ConnectorMaxx hardware cannot be incorporated. And so it’s very important that you locate your sales rep and understand what you’re trying to accomplish and they will include the most appropriate ConnectMaxx hardware for whatever it is that you’re trying to accomplish.
And it’s all put together with a single Allen wrench, which is included as well. I’m more than happy to respond to anybody’s questions that you have. And I encourage you to join us again next week. Okay Dave, one second I’ll answer that, one moment. So, again, feel free to email me if you have any particular questions check our solarwebinars.com for archives of all the webinars. I think we’re up to, actually I don’t even know, 16, 17, 18 webinars at this point.
So, we’re giving quite a lot of information to you guys as quickly as possible. If you have any suggestions for webinar topics that you’d like to see I am definitely interested in doing that as today I’m doing another schedule for the third quarter of 11, so please do take advantage of that. Send me emails with your questions and I’ll be happy to respond. Now, in terms of wind load, before we close, the wind load for flat plate collectors, the hardware is rated for 110 mph winds. Okay, so we have passed and rated our hardware at 110 mph winds. It’s apparently in testing right now for 160 mph winds. According to the mathematics that we’ve used it will pass the 160 mph test, but we don’t have that official stamp of approval yet. But, we do have a rating at 110 mph winds for both flat plate and evacuator tube. As you know evacuator tubes suffer from much less wind load than flat plates and require less material to connect to the roof. However, since our ConnectMaxx hardware is universal we’re using both flat plate and evacuated tubes for this hardware, they are, in the case of evacuated tubes, the hardware is probably well exceeds what’s required in order to hold it down in, you know, hurricane force winds.
Okay, well there you have it. I’m going to officially end the webinar. Don, I went with flat plates on my house because of a radiant floor where I needed extremely low temperature heat load and it is also a question of aesthetes in terms of my house design. And so that’s a very good question and it’s not an easy answer. I went back and forth with flat plates versus evacuated tubes and it really just came down to what is most applicable for my particular application. Okay, thank you all take care and have a great Monday and I wish you the best of all available sunshine. Take care.