Heating Help

Ivan Labs

@ March 15, 2009 9:51 PM in DC Solar pumps for radiant

El Sid pumps are another option, a little smaller than the Laing's. I prefer either of those to the March and Hartells on the basis of noise produced. I've gotten in situations where I was convinced by the off-grid electric guy on a job to use a smaller pump than I would have otherwise, in order to save the relatively scarce PV watts. Hasn't always worked out well, so I'd encourage you to make sure you've got enough flow to deliver the desired heat. Or install more tubing, fintube, or whatever you're using for delivery. Roy

I've worked on a couple systems

@ March 9, 2009 10:36 AM in High Mass Solar Storage

which were "high mass solar storage." Both designed by Bob Ramlow of Artha Sustainable Living in Amherst, WI. His book: "Solar Water Heating: A Comprehensive Guide to Solar Water and Space Heating Systems" gives some detail about these systems. They generally involve a couple foot insulated sand bed under a slab floor with PEX tubing delivering solar heat to the bottom of the sand bed. The idea is storage massive enough for some degree of seasonal lag, so late summer solar heat can help out during the heating season. Both the systems I worked on have had some problems. The first I inherited midstream from a solar installer who went out of business and the collector array has had air problems that are yet to be resolved so no good test winters yet. Second house which I did the entire install has been used as a seasonal residence which really is not well suited to the system. The whole mass cools off when the house is unoccupied and then when they warm it up for winter use, the mass is working against you. So I really haven't had a chance to evaluate these systems but I know Bob lives with one and has been involved installing dozens that he says perform well. My gut sense is that though part of what he like about them is the simplicity, it might be more effective to complicate them some by thermally separating the slab delivery from the storage bed and having a controlled heat delivery from storage rather than the passive & uncontrolled heat delivery in the way he does it. I'd also note that I have intended to but have not yet done calculations to really look at the heat capacity of the sand bed and how it relates to the heat load and solar potential. Someday soon ... ;-) I know of at least 2 systems that have been done with high-mass sand beds that were thermally isolated from the delivery slabs. One featured in Environmental Building News maybe a year and a half ago, one done by an outfit from Duluth MN. I'm heading tomorrow to Duluth for an Energy Design Conference where the installers of the latter system are doing a presentation. So I'll see if I can get some more info and post later in the week. Roy Sunrise Energy Services

I've worked on a couple systems

@ March 9, 2009 10:36 AM in High Mass Solar Storage

which were "high mass solar storage." Both designed by Bob Ramlow of Artha Sustainable Living in Amherst, WI. His book: "Solar Water Heating: A Comprehensive Guide to Solar Water and Space Heating Systems" gives some detail about these systems. They generally involve a couple foot insulated sand bed under a slab floor with PEX tubing delivering solar heat to the bottom of the sand bed. The idea is storage massive enough for some degree of seasonal lag, so late summer solar heat can help out during the heating season. Both the systems I worked on have had some problems. The first I inherited midstream from a solar installer who went out of business and the collector array has had air problems that are yet to be resolved so no good test winters yet. Second house which I did the entire install has been used as a seasonal residence which really is not well suited to the system. The whole mass cools off when the house is unoccupied and then when they warm it up for winter use, the mass is working against you. So I really haven't had a chance to evaluate these systems but I know Bob lives with one and has been involved installing dozens that he says perform well. My gut sense is that though part of what he like about them is the simplicity, it might be more effective to complicate them some by thermally separating the slab delivery from the storage bed and having a controlled heat delivery from storage rather than the passive & uncontrolled heat delivery in the way he does it. I'd also note that I have intended to but have not yet done calculations to really look at the heat capacity of the sand bed and how it relates to the heat load and solar potential. Someday soon ... ;-) I know of at least 2 systems that have been done with high-mass sand beds that were thermally isolated from the delivery slabs. One featured in Environmental Building News maybe a year and a half ago, one done by an outfit from Duluth MN. I'm heading tomorrow to Duluth for an Energy DEsign Conference where the installers of the latter system are doing a presentation. So I'll see if I can get some more info and post later in the week. Roy Sunrise Energy Services

if I understand

@ March 1, 2009 1:43 PM in solar drainback

the Sol-Reliant system correctly, the "Fat Tube reservoir" below the collector header serves the same function as a separate drainback tank would in a more "traditional" AC pumped drainback system. for my climate, I think there would be a significant heat loss from that fluid during non-operative periods (esp. in winter). but it highlights for me the tradeoffs that come with different designs and how challenging it is to know how different elements effect overall system performance. how does the energy saved by PV pumping compare to the energy lost by the drainback reservoir being outside? I sure don't know. without side-by-side testing in particular climates, its kind of a tough judgment call as to what's "best." Roy

interesting approach

@ March 1, 2009 10:32 AM in solar drainback

with the Sol-Reliant. nice to be able to PV pump. not so sure if I'd want my drainback tank outside the thermal envelope. low temp here the night before last was a new record for the date of -25, which is to say I'm in a cold climate, and to store a chunk of the system fluid outside the heated envelope is a downside. Roy

which Taco

@ March 1, 2009 10:21 AM in solar drainback

are you referring to, MD? I couldn't find any DC pumps on their site. I did find something new to me, a line of variable-speed AC solar circulators, with integrated solar controllers. interesting. http://www.taco-hvac.com/en/products/Variable%20Speed%20Solar%20Control%20%2200%22%20Circulator/products.html?current_category=371# is that the one John showed you? Roy Sunrise Energy Services

ditto on the Laing

@ March 1, 2009 10:14 AM in solar drainback

they are very quiet, appear well made and of a durable innovative design. cheaper than Hartell & March options, which tend to be unacceptably noisy to my tastes. Roy Sunrise Energy Services

glycol drainbacks

@ February 26, 2009 10:35 PM in solar drainback

as has been mentioned here before, in WI, a state with a very active solar community and state support program, glycol is required in drainbacks. don't know the history behind that decision, but I believe that WI only came to permit drainbacks in state-rebated systems fairly recently, and then only with glycol. my sense is that they are a little worried about poor installation and its a second layer of "insurance" that the system won't freeze. I've been working with Solar Service of Niles, IL, who have been doing cold climate drainbacks since late 70s. many water-only systems without problems. they now mostly do glycol drainbacks, my understanding that with glycol they mount the arrays level rather than pitched and don't have to worry about being absolutely positive that the headers will drain. they feel that the looks-square-aesthetics of a level array are worth it. as far as pairing solar with on-demand units, some models advertise as being compatible with solar pre-heat, some do not. I stick with the ones that say they are suitable. none of them modulate all the way down to nothing so I'm not sure how they handle water preheated to just under the normal output temp. I've heard of others using a 3-way zone valve to bypass the on-demand unit if the solar tank is up to usable temp. my approach is to run it through the on-demand unit but to route the power for the (gas) on-demand through the upper thermostat on the solar tank. then when the tank is up to temp, it will cut power to the on-demand and you won't get the on-demand starting up to heat the first slug of water from the pipes and then shutting down when the tank water gets there. saves some short-cycling of the on-demand and reduces the temp fluctuation at the tap. Roy Sunrise Energy Services

I'm with Andrew on this one

@ December 11, 2008 8:18 PM in To Dan Holohan

having started 30 yrs ago in solar thermal, migrated to radiant & hydronic systems, & now back focussed on solar thermal, I see solar hydronic as a subset of hydronic in general. and I think its good to to view solar info within the larger context & knowledge base of hydronic systems. it offers benefits to both solar folks who don't have the overall hydronic background and to "conventional" hydronic folk who can then start seeing solar apps as something they can add to their bag of tricks. Roy

it would be nice to have a couple day notice

@ December 8, 2008 6:33 PM in DanH - let me know if you want help installing new forum system

to save stuff from the current site. (no time like the last minute!) and it would be real nice to have the current forum archived in some fashion that could be accessed & searched. not only will we have Dead Men but a Dead Forum. Roy

the discrepancy between thermal and PV certified installers

@ December 4, 2008 10:50 PM in Nabcep test for solar thermal

is interesting ... and kinda reflective of the popular image of "solar energy" which has morphed from 30 years ago being a heating technology to now being an electrical generating technology. when I tell people I work in the "solar" field these days they more often than not start asking about PV. despite the fact that thermal applications are still generally the most cost effective. go figure. a friend of mine who is sort of a PV guru, is PV nabcep certified, and is on the board of nabcep, says the PV test is quite tough - many people have to take multiple times, but left me with the impression that the thermal test is not as bad. hope he's right and that the questions are good. Roy

OK

@ December 4, 2008 10:40 PM in Nabcep test for solar thermal

well - I guess this gives me a different picture than I got from the sample questions in the study guide, which struck me as pretty simplistic. I guess if the winter turns out to slow, then I will always know what I can be doing ... (studying! - and that's not necessarily a bad thing - always more to learn and assimilate - but I do hate having to deal poorly worded and conceived questions). for example, I'd say that aluminum has the better heat transfer properties, but I have no idea what "engineered" means in that context. onward - Roy Sunrise Energy Services

is the sample exam

@ December 3, 2008 8:44 PM in Nabcep test for solar thermal

in the NABCEP solar thermal study guide actually representative of the test in your experience? it seemed surprisingly non-challenging ... michael - the test itself is in March; January is the application deadline. Roy Sunrise Energy Services

I don't have a copy

@ December 3, 2008 4:13 PM in USE solar codebook revisions any suggestions?

of this codebook to know what's in there and what needs changing. am I correct in guessing that you have to buy it to know? (or is it available online) Roy Sunrise Energy Services

two other books

@ November 29, 2008 10:52 AM in organizing assorted solar questions

which I have found useful and which nicely complement Planning and Installing Solar Thermal Systems: Tom Lane's "Solar Hot Water Systems: Lesson's Learned" (MUCH info - and could use an organizing editor): http://www.ecs-solar.com/lessons_learned.htm and Bob Ramlow's "Solar Water Heating: A Comprehensive Guide" which is less detailed than the other two but still is worthwhile: http://www.amazon.com/Solar-Water-Heating-Comprehensive-Systems/dp/0865715610/ref=sr_1_1?ie=UTF8&s=books&qid=1227973569&sr=1-1 Roy Sunrise Energy Services ps - I forgot to add the Caleffi manual to the list but it should be there. clear, succinct & free! http://www.caleffi.us/caleffi/en_US/Site/Technical_library/Idraulica_magazine/index.sdo

maybe I'm not being too clear here ...

@ November 28, 2008 11:50 PM in organizing assorted solar questions

I'm not new to the field - spent a year and a half in a solar installers training program in the late 70s and about 5 years doing solar work after that. over the past couple years have re-entered the field. just completing a job putting in 24 drainback water heating systems on a tribal low-income housing development. so I'm not a complete newbie, but am still very much figuring out what are my preferred details and materials for various systems. trying to not reinvent any more wheels than need be or inflict too much of my learning curve on clients. and I presume others have similar desires. I guess one thing that's behind my initial question is the dance of having considerable curiousity about how others are designing/installing - while striving not to hijack threads or redirect them with tangential questions. and the thought that there are threads that are in themselves like FAQs and it would be nice to have a mechanism to access them & potentially keep them live & growing while doing so. thanks - Roy

I suppose

@ November 28, 2008 8:48 PM in organizing assorted solar questions

the short response to what I'm looking for is answers to my questions about solar systems and also recognizing that in many cases there are not simple answers, only questions with a variety of opinions as to the answers. so I'm looking for, as I said: "some real focussed and evolving compiled knowledge" and recognizing as the solar thermal field grows in this new era of interest in renewables, there are lots of hydronic pros out there with similar desires. this site is a great help. I was just speculating about how to make it even more useful. how can you help me? by weighing in on threads that you have some expertise. thanks - Roy

I've been watching solar threads ...

@ November 28, 2008 7:15 PM in organizing assorted solar questions

in particular here lately. I'm seeing both that there are more & more over time and that they often end up revisiting one or more of a set of primary questions about solar system design, installation and operation. such as flat plates vs evacuated tubes, drainbacks & pressurized closed loops, heat exchangers, storage tanks, heat transfer fluids, pipe insulation, etc. and then the responses to those questions end up scattered around in lots of discussions that often ramble around, topic wise, as one thought leads to another. in a way that's just the nature of the beast in a forum like this, and truth is that I find the search process here to work pretty well for trying to track down info on a question ... just this week Dan's regular email reminded me of a feature here that I've browsed before, the "Systems FAQ" page. http://www.heatinghelp.com/heating-help.cfm?pageid=32 on that page in the solar section I saw there are 3 archived threads (all from early this past summer): Drain-back systems; Solar rights: and Which is better, flat panels or evacuated tubes? excellent! seeing those made me think: would it make any sense to identify some key "primary" solar thermal questions, start separate threads that are related to each of them, and then archive the threads - or better yet, link to them, so that they could stay current and live over time. not to discourage new threads and questions, but to compile some base topic discussions that could save time on the search feature and lead to some real focussed and evolving compiled knowledge. guess my "inner organizer" must be up and happening today. anybody else think this idea is worth pursuing? finally, I'm reminded that on the professional front, this site is definitely one of the tools for which I am most thankful, not just at thanksgiving, but year round! thanks Dan, thanks all of you! Roy Sunrise Energy Services

IMC now has a DC controller

@ October 27, 2008 11:05 PM in DC pump for SDHW

on their website. I've been using their Eagle 2 controller lately and like it. The DC controller looks pretty much the same except for running off 12v DC instead of AC http://www.solar.imcinstruments.com/

happily ...

@ October 27, 2008 1:17 PM in wall cookies?

I just used Mac's Time Machine backup system, and restored my cookie file from a couple days ago, and all is well. like more than a few things in the hydronic world (and larger world!), I was able to get the results I wanted without truly understanding the territory in which I was operating ... thanks, Dan (& Brad), for the prompt response. as always - this is such a user friendly, generous, & helpful site. for any other Mac users dealing with this issue, the cookie file is at user/Library/Cookies, and with Time Machine, it is quite easy to recover an older version. Roy

but

@ October 27, 2008 12:54 PM in wall cookies?

I hate starting over with an empty jar trying to figure out how to recover my list of bookmarked threads if at all possible and I confess to being a bit unclear about what constitutes "sharing a hyperlink" so I'm not sure what I did that might have caused this. feeling a bit melancookie ...

I liked my cookie better

@ October 27, 2008 12:38 PM in wall cookies?

how the heck would I get somebody else's cookie and who's got my cookie. I'm generally quite fond of cookies but this sort is kind of mysterious for me ...