deleting your own post

scott markle_2

I think the ability to delete your own post would be a good feature, Misspelled Caleffi along with duplicate posts. Sorry



Flow sensor all hooked up (on the hot side), will call them about plugs in the morning. HR (if you catch this) have you wired any of these?



Geting very Psyched to measure some real world flat plate solar performance.

Mark Eatherton

You'll know the output...

How are you going to judge the input? Got pyranometers laying around? Flux sensors and appropriate meters in your shop?



Let us know how it works out. Nice clean array by the way.



ME

scott markle_2

performance Vs. efficiency

I'm interested in performance in a general sense. I'm not reinventing the wheel and I don't think I need any of that gear to make some informed judgments about performance.



I will be measuring energy collected (at the tank) as opposed to delivered at the tap so there will be storage losses that will not be accounted for. Still measuring flow and temp at the coil should give some very useful information as to the real world energy collection capabilities of this installation, commissioning in january should be especially informative.

Mark Eatherton

Gotcha...

Let us know what you find, won't you?





ME

Paul Rohrs_14

Layout

I love the layout but it raises the question about potential liability.

It only took me a half a dozen times of touching a hot stove as a kid for it to sink in that it was hot. 

Any concern about ground mounted collectors and the exposed surfaces that could be in contact with people that don't realize the potentially high temperatures?  (Sadly enough, we live in a land that is litigation friendly)

Just wondering out loud.

Paul

hot_rod

ground mount arrays

are becoming more popular. Here are a few thoughts.



Find some of that aluminum wrap for your insulation. I think it looks better and will preserve the life of the insulation. If you insulate all the piping and vents there should not be any exposed hot surfaces. Those aluminum covers and fitting covers make it fairly tamper proof. My local insulation supplier will roll that aluminum cover to the exact diameter you need.



You can do some basic energy metering with the control alone. You use the OHQM (option heat quantity metering)



You need to know the flow rate, if you use a Solar Pump Station it has a flow meter built into it. Beware the control may ask for l/min. Some of those flow meters read both GPM and l/min.



l/min. X 3.78 = GPM

Then place a sensor on the return piping to the collector.



So now you have the flow and delta T. The control calculates the KW "harvested" It does work in the variable speed mode also, the control does the calculation.



Or you can use the Grundfos sensors. They all read temperature. One version is pressure and temperature, the other flow and temperature.



The cap on the flow sensor snaps off and use the "patch cord" to connect to the control. I'll see if we have these in stock yet, we had some extra long ones built, the factory ones were too short to reach the control unless it was mounted right on the Pump Station.



We did get the manufacturer part number for the mini plug you need to fit into the BX control. it is a tough plug end to wire without the special tools, sort of like a Cat 5 plug.



The cords we have, or should have will have the Grundfos plug on one end and the mini plug to fit into the control on the other end. i will call and see if they are in yet. Sorry about the hassle.



After you connect everything the control will prompt you through all,the inputs to reconize the Grundfos sensors.



hr

scott markle_2

wires, and pipes

Thanks, for the reply. I spoke to Rex in Wisconsin yesterday he's expecting some new connecting wires from germany soon.



One thing I noticed is that the wire to the pressure sensor is removable, it has a metal band that snaps around the back of the sensor to secure the plug. The flow sensor wire does not have the same type of connector, In-fact it looks to me like it's not removable from the sensor at all, perhaps it's an earlier version. I'll probably have to splice the wire on this one.



I was aware that I could do energy metering without these direct sensors but I thought it would be based on the delta between the collector sensor and the one at the coil.

I have a long exterior line set and wanted to meter at the coil, are you saying this (delta at tank measurement ) can be configured with standard sensors?



Paul I'm not so concerned about someone touching an uninsulated pipe, there shouldn't be any of that when I'm done. However I'm a little paranoid about stagnation temperatures and pressures (65 psi) and the possibility of a connection failure if somebody was in close proximity.



We will probably put up a low cedar fence and plantings to keep people away from this general area. Perhaps a small tastefully designed tag that indicates the potential dangers (with some fine print legalese that absolves me of responsibility... LOL ) would also be a good idea.

Bob Gagnon plumbing and heating

Low Temperature Collection

Are you using this collector for Domestic only? IF you could measure it at the higher domestic temperatures, 130 degrees, and then if you measure it at lower radiant space heating temperatures, 75 to 80 degrees, I think you'll find you will collect about twice as much energy. I think everyone is doing it wrong by going after the domestic load first during the winter, then whats left over goes to space heating. Take those 75 to 80 degree btu's directly into your house to harvest a lot more energy.



Thanks, Bob Gagnon

scott markle_2

heat VS. hot water

Hey Bob, I see your point, and I'v seen the graphs that show the relationship between ambient and supply and it's effect on efficiency.



There are certainly ways that solar output could be switched between a space heating load and DHW, however I'm not aware of any that are terribly simple or inexpensive, especially if we want this to be handled in a fully automatic manner.



This system is closed loop glycol, it's been cloudy and cold since it was commissioned.

the small amount of sun available has been able to get the 53 gal solar tank to 90 deg.

I don't believe I will ever see 130 in dec-jan, even if there was very little DHW use. There is only so much heat available from the often cloudy NY winter sky. I'm waiting for the direct sensors so I can do more than speculate.



I don't believe the hardware necessary to elegantly tie this array into the heating load in a selective and automatically regulated way would be justified based on the added cost and complexity. In other words the amount of energy that 2 flat plate collectors can "collect" in mid winter (here) is not so significant as to justify the expense of the slightly higher efficiency that could be achieved by serving a low temperature heating load as opposed to DHW.



Ultimately I expect that this systems (dead winter) solar tank temperatures will be fairly close to radiant heating temps anyway, which is still quite a bit of help considering the frigid municipal water that we get here in the winter.

Bob Gagnon plumbing and heating

SImple Solar Space Heating

This is simple and efficient. You will have to add a separate radiant panel, maybe in a bathroom and/or behind you living room couch, so that you can harvest energy even when your solar heating system won't cover the whole load. The all or nothing solar space heating systems with the super complicated and expensive control systems, will only harvest low temperature energy during the shoulder season, a few weeks or so during the spring and fall. Having a separate supplemental heating panel will allow you to collect a lot more energy because it will keep your tank temperatures low so your collectors will harvest the maximum amount of energy. You simply run your delta tee controller to your heating tank during the heating season, and collect all energy over 75 degrees. You have a separate thermostat on the solar space heating radiant panel tied to an aquastat the circulates heat from the tank to the radiant panel whenever the tank is above 75 degrees, when you come home from work and take showers the temperature in the tank will drop even more. In northern Massachusetts here we have water under 40 degrees from mid winter to mid April, that means you tank temp may drop to 50 degrees or so and that means you will start collecting solar energy the next morning when the collectors temperatures rise above 55 degrees. Making the system MUCH more efficient. In the summer you simply run the delta tee controller to the primary domestic tank and run your solar system like a conventional domestic solar hot water system.



Thanks, Bob Gagnon

hot_rod

Nice

drawing, Bob. They look so simple and clean on paper



Missing is the means to heat when there is no solar available, and the DHW source when the solar is to low to provide 100%



Piping wise it is not much to add to a drawing. The controls, especially 100% automatic including overheat protection do tend to become a challenge for installers.



You drawing does make it simple, it does requires 5 heat exchangers and storage tanks to allow that.



hr

Charlie from wmass

Bob you said the heat emitter

was supplemental heat right? As you have another heating system set up as primary heating. The thing that keeps me away from solar and wood systems is the room required for large thermal storage. I do not think the consumer would realize the space required for 1200 gallons of water. You also better make sure you have a good sump pump or floor drain system to deal with that if it were to develop a leak.

Gordan

Correcting a minor slip

1 gal = 3.78 L, so L/min should be DIVIDED by 3.78 to get gpm. Just in case someone reads this and is in danger of scratching right through their skull. :-)

Mark Eatherton

3' X 8' foot print....

8' tall gives 1440 gallons of storage...



Surely there is some space available for a site built non pressurized storage medium SOME where...



As for leakage, the chances of the non pressurized storage tank leaking are less than the pressurized water lines in the same mechanical room and relief valves, etc...



ME

Bob Gagnon plumbing and heating

Simple Solar

Right Mark, my tank holds about 1500 gallons and it's 8' X 8' X 4' high, but you don't really need the tank that big. You are using your house as storage if you send low temperature energy from the collectors directly into your house. I have a big tank because I get 100% of my domestic hot water from solar and because I don't want to have to dump any heat, with my large collector surface. As for leaks, I feel pretty comfortable with heavy duty roll rubber roofing with no seams, and not being pressurized it can only empty the tank, it wouldn't leak continuous like a standard tank would. Charlie's right, this is a supplemental heating system,but that makes it a lot more efficient, because it can supply heat to your house on every sunny day during the heating system, by doing this you keep your tank temperatures low, making your collectors much more efficient. Hot Rod, the cold water gets preheated in the cooler space heating tank, then it gets topped off in the primary domestic solar tank, allowing the heat to last longer there, after that it could go into a superstor to insure hot water all the time, I skipped that, I just tough it out for a hand full of days a year and take 90 to 100 degree showers on those days, no big deal. I'm not sure what you mean by 100% automatic, you will have to switch the delta control wire from one tank to the other during the heating season, but I think that's it. I haven't installed the 12 volt pump to protect my evacuated tubes during a power outage, control or pump failure, do you see any problem with this?



Thanks, Bob Gagnon