Joined on May 29, 2008
Last Post on October 8, 2012
@ October 8, 2012 8:47 AM in Solar water heater electric backup overheat tripJoe,
How about using a ac/dc relay switch to control the pv pump :http://static.schneider-electric.us/docs/Machine%20Control/Relays%20and%20Timers/Relays-General%20Purpose/Relays-Miniature/8501CT0301R708%20Relays.pdf.
That way the PV pump can run on a differential like an AC pump would. I thought about this a few times because I noticed the pv pump would start early and run late causing a cool down in the storage tank.
@ October 3, 2012 10:52 AM in solar expansion tankof the condensers? I would like to see what they look like. I have seen Vacuum tubes go bad. When they do, they get a creamy white color at the condenser point on the glass.
@ July 12, 2012 4:52 PM in Solar thermal websiteHas anyone checked out Rod Hyatt's of HTP website for solar thermal?
@ June 18, 2012 1:54 PM in Pipe flow softwareI am looking for a program that determines flows and pressure drops through pipes and storage tanks. Free would be helpful
@ June 14, 2012 2:53 PM in tie in SHW to commercial boiler roomKevin,
The 24/7 recirc is there to stay. I had a meeting with the mech. engineer of the bldg today. He is adamant that i do nothing to interfere with it.
I like what Fortunat proposed above in his reply. I would not rather use a three way though. I will if that is the best approach. I like having the pump on a differential tied in to the DHW out the Aux. tank, back into the cold supply to the solar tanks. I have not ruled out a three way valve.
I really appreciate everyone's opinion's on this and I am open to further discussion. Thanks again dan for this great forum!
@ June 13, 2012 10:15 AM in Pipe sleevingWhere are you purchasing the material for jacketing the exterior pipes and insulation for the solar loop?
I thought if I re-adjusted my original post I may get a reply. : )
@ June 13, 2012 9:51 AM in tie in SHW to commercial boiler roomKevin,
I like your idea, but I don't want to add another pump for one simple reason; I would have to add a separate controller.
I am using an EnerWorks System (not by my choice) and they have a pump station that has a controller designed into it (they call it CSET). Looking at their spec sheet there is not a relay to add a pump. What I COULD do is add a small plugin recirc with a timer. This would at least circulate the heat from the solar tanks into the aux tank.
I am attaching a updated drawing with your suggestion on it.
Thanks for your help
@ June 12, 2012 11:01 AM in Mixing ValveI am down to two different valves. A leonard: TM-2020B-DT or Powers: SH 1434-14.
Cost are similar. Does anyone have any opinions on which valve is more reliable? Or is there a better valve?
@ June 12, 2012 10:54 AM in tie in SHW to commercial boiler roomI am aware that the tanks may sit hot all night without draw. Do you have an idea to get around that?
@ June 12, 2012 8:21 AM in tie in SHW to commercial boiler room# 2 Is always my standard option. But the buildings engineer came up with Number 3. Number 1 was the facilities MGR idea.
On #2, The Engineer is worried about the solar mixing with the hot from the boiler since they tie in together (see photos). Valid point, but there is not many options. The Aux. Tank is a 500 gallon tank. Once the Solar Pre heated water hits it, the boiler will not fire. He still does not like it!
I'll attach an updated drawing.
Thanks for the input
@ June 11, 2012 8:42 PM in Mixing ValveAs long as the components are quality items, that is all that does matter.
Big building, bigger price.
@ June 11, 2012 8:36 PM in Mixing ValveI will edit my post.
8k! Wow we!
@ June 11, 2012 8:34 PM in Mixing ValveMark,
I agree 100%. If I thought I could get away with the pre heat tanks plumbed in series it would be a done deal. I'm a little leery though. So is the engineer I am working with. Shoot, he is specifying 3" copper even on the tanks.
I would love to see a drawing of the reverse return on 3 pre heat tanks. The pyramid style that I have in the drawing did not excite me. I know I can make it look good, but man that is a lot of copper.
Can you post the reverse return or email me direct.
Thanks for all your help Mark
@ June 11, 2012 8:16 PM in Mixing ValveAre you calling Caleffi Cheap? Do you hear that Hot Rod? I'm just kidding of course.
I hear you Icesailor. I think I was a little sticker shocked. This is my first commercial install and $xx00. for a mixing valve blew my pants off (believe me, not worth photographing).
I was expecting around $xx00. As long as it functions properly and everyone is happy then it is well worth it. Amen to that!
Thank you for your bluntness. That I really do appreciate.
@ June 11, 2012 3:34 PM in Weben-Jarco, boilerSupposedly,
Purchased by Green Boiler Tech.
@ June 11, 2012 2:40 PM in Mixing ValveSticker shock on the leonard valve.
Doesn't Caleffi make a similar valve?
This is a 127 unit residential bldg. There is no commercial facilities for cooking. Each unit has a kitchenette with no dishwasher. Most people are over 60 that live there.
Let me know,
@ June 11, 2012 1:13 PM in Mixing ValveLeonard seems to be the answer. They were very helpful.
@ June 11, 2012 12:15 PM in Weben-Jarco, boilerSH,
I did get that info off google also. But the number is disconnected and the website in pretty much none functional. I should of mentioned that in my original post so you didn't have to do any fancy foot work.
@ June 11, 2012 12:08 PM in Mixing ValveMy Comments are below your paragraphs:
Extended care facilites, and nursing homes don't have any "normal" hot water usage patterns, so the engineers who design these systems typically cover their butts, meaning the system is grossly over sized. ASHRAE doesn't even attempt to generate a usage profile chart like they do for other facilities.
Yes, this I know!; ) I tried desperately to get them to put a meter on the DHW to help size this system. It never happened.
In reality, you need to do due diligence, and talk to the people who are using the system (administrators and their assistants) to gage exactly what the largest hot water load would be. Laundry facility? Full service commercial grade kitchen? These loads will be much greater than the DHW loads, and the chances of having parallel loads is slim to none. Old folks don't shower as often as younger folk do, unless there is a schedule bus trip to a bingo parlor or casino, then EVERYONE wants to smell good ;-)
To clairify, this is a Co-op living center. The residents have their own laundries and cooking facilities.
Over sizing an anti scald tempering valve can actually cause more problems. Valves are designed for certain "minimum" flow standards. If flow drops below this minimum, and they will, then the system starves for hot water because the cold water pressure will always be greater than the hot water pressure due to inherent pressure drops through tanks, etc.
That is my worry. Old people hate cold water (at least most). My worry is choking off the hot water supply.
Conversely, undersizing a tempering valve is also problematic, hence the 2 stage systems that HR told you about.
It is up to you to choose a "Happy Medium" to design around. I'd also recommend two valves so that hot water service can be maintained at all times, especially when rebuilding the valves.
Just because the mains are 3" is not necessarily an indication of the required mixing valve size. Those pipes sizes were based on flow potential, which in reality, is a moving target and is usually no where near the rate the designers used in their design.
Good to hear.
In regards to your solar design, you should have a tempering valve between the solar preheat and the aux system, otherwise, during peak insolation it is possible to send too hot of water into the boilers, thereby causing their on board manual reset high limit to pop, and you will not know it until its out of hot water.
Yes, I agree. I am fighting with a couple of engineers on that point.
Also, regarding your SPH tanks, they will all be the same temperature because they are all seeing the same flows on discharge and recharge. They are in parallel.
Originally I had them is series. My concern once again was the flow rate. Me and my engineer friends decided to change to parallel for that reason. I usually always put them in series, but I was eagerly swayed. What is your opinion on this Mark?
If you wanted three different tank temperatures, then the tanks would have to be in series, not parallel. I see no advantage to that in my minds eye, but its also Monday, and I'm only on my first cup of Joe...
I couldn't sleep because I am letting all this bother me. I didn't need coffee today! lol
@ June 11, 2012 10:11 AM in Mixing ValveI am tying in a solar thermal to an existing 9 story 127 unit residential building. Mostly elderly.
I am worried about loss of flow in the building installing a smaller mixing valve. I'll attach a drawing to help clear my mud.
If I can put in a smaller diameter mixing valve, say 2" with minimal flow loss that is great!
Thank for the help
@ June 11, 2012 9:48 AM in tie in SHW to commercial boiler roomThe Enginner at EnerWorks solar want it plumbed the way in the attached drawing. Which I do agree with to a point.
Is has been impossible sourcing a mixing valve for three inch. And if I do find
one, the cost is going to be indecent. I would like to re-figure this so the
piping for the tanks and through the mixing valve are 2". What will this do to
the flow rates and pressure drops?
If I have to go 3" for piping that is fine, but the cost are going to be
astronomical and blow the payback out of the water. BUT most importantly I
want this system to function properly.
Thanks for all your help on this.
@ June 8, 2012 11:35 AM in Pipe sleevingWhat type of Jacket/sleeving is everyone using on their commercial solar thermal installs? Aluminum jacketing? PVC?
On residential I use PVC sleeving.