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Why the sophisticated expensive controllers?
Comments
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TRV/FHV
Please educate me, I'v used TRV's (thermostatic radiator valves) is what I assume this stands for. But please tell me what does FHV stand for and what are these valves used for?0 -
Once I installed, used and observed TRVs I had serious doubt about the ability of even the most sophisticated electronic controls to replicate.
A fully TRVd system naturally produces order fromchaos. Electronic (on-off) controls no matter how sophisticated attempt to produce order via chaos. Such chaos isn't a problem when turning analog audio into digital because you can always sample at at least twice the frequency any reasonble human can hear--but with heating systems operating valves and/or circulators--think MINUTES not micro-seconds...0 -
FHV
Floor Heat Valve.0 -
Funny you mention vinyl...
One of our best customers in Linden, NJ makes vinyl records and dows very well. We maintain the steam boiler that heats the kettles to melt the material, as well as heats the "bake room" where the vinyl is cured.
They merely make the blanks, no pressing.
One of our best payers as well. I suspect business is very good indeed.0 -
i see no difference
between a digital and analog controller, other than the digital controller is a simpler device.
a trv is nothing more than a sensor/controller and a variable valve. don't understand chaos in a heating system?0 -
trv's vs. tn4
Mike the main difference between trv's and a Tn4 room sensor is this. If your "global" heating curve is set only slightly above what is required to heat the space( with no flow restriction to radiators) then recovery from an unoccupied addjustment is going to be very sluggish. A tn4 system will readjust the "global" curve to assist in recovery of a zone which is far from target, It will simultaneously calculate what the effect of this raised curve will be on zones that were fine with the original curve by a calculated pulsing (on/off) operation to these zones.
I'm not advocating these systems for poor old ladies, It is a bit expensive but so is labor and copper and everything else.
In a well balanced system I'm not so sure how important trv's are anyway. I'v done some one zone home run piped panel rad. vitodens jobs with no trv's that work beautifully. No indoor feedback at all. If you really want to keep it simple this works great, you just need a careful heat loss calc. no bypass valve lowest possible return temp. etc.0 -
HTML fix
Sorry. Not at the right computer to fix in the thread0 -
"Simpler" is in the mind of the boiler and occupant...
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i was
refering to the circuitry....
my reference to 'digital' means digital electronics not oftened called here bang-bang controller.0 -
An analog circuit is far simpler than a Digital circuit
IF you can find someone to design and build it for you; analog is very simple - and far simpler than any digital circuit.
Only problem is that it will only work on your specific application and cannot be reprogramed to do another application. All you might get would be a bias adjustment. But they are very simple and work really great.
when studying controls (advanced control lab, not just the theory) they start you out by having you model then build a series of analog controllers for a variety of things. Then they have you build a simple digital controller and play with sample rates and measurment increments so you can see the effects of not enough and too much sample rates and measurement increments. For building these controllers you are litterally assembling chips onto generic circuit boards and point to point wiring them and the other components together. All you get is a standard power supply output, and a timing clock output for the digital devices.
It is very educational.
Only then do they move you into the current available commercial controllers - and then the advanced stuff.
Things I played with in a fall 1985 controls lab (the advanced stuff) did not hit the market until the early 1990's; and one plant manager in the mid 1990's though I was a genius when I started reprograming his new boiler controlers to make them work (a new "used" 500,000 Lb/Hr boiler: I was one of the contractor startup operators - a 2 week temp job).
I have since designed and built several analog control circuits. They are really elegent.
Perry0 -
No, but... More info on Vacuum tubes
No. The Modulus system was sold for I believe a couple of years and then was replaced by the next model. It could be that the "Pro Line" was the replacement.
I am glad that your old Heathkit amplifier is still serving your needs well. I too build Heathkits and they were great products (but I don't have any of them anymore. I'm not even sure which of my brothers and sisters has the stuff I built).
One interesting thing that came up on my internet search on vacuum tube amplifiers.... One article I read listed the "old" equipment that was worth salvaging and reconditioning. There words were golden for Heatkit amplifiers and along the line of "Any and Every Heathkit amplifier would be worth reconditioning - and that some of them were as good as anything ever made."
A couple other interesting things...
Consumer sized vacuum tubes is currently about a million tube per year market.
The best tubes are currently made in Eastern Europe factories.
No one is makeing tubes as good as the old production tubes. They are not using as high of quality of materials nor vacuum pumping the tubes to the standards of old - these factors shorten the life of the new tubes (but one small company is looking at it).
Most tubes that are represented as old stock are relabled modern production - almost always from China (the worst production of the new tubes). They even print old stye boxes and ding them up to put those relabled tubes into.
For the most popular amplifier tubes. Authentic old stock is very very very rare.
One writer has never found an ebay offered "Old Stock" tube to be a real old stock tube. All of the ebay offered "old stock" tubes have been found to be fradulant.
There are several internet based companies who test and match tubes for amplifiers to ensure that you are getting good tubes (even from new production).
For very high power commercial amplifiers and related high power products... (way beyond audio needs) there is still a production line in the US producing high quality tubes the old fashion way. However, most people will never even see a vacuum tube that large as it is way beyond what would ever be installed in home or small commercial equipment.
Perry0 -
to put it another way, with TRVs/FHVs the occupants have to work around how the system operates; it doesn't recover temp fast, you can't easily do a full system setback, and you *still need* electronics for the outdoor reset, etc.
With tN4, the system works around how the occupants want to live. If they want to setback, fine, it'll boost out, and settle back down when it can. Hit a button and the whole system drops down. You get your DHW priority, outdoor reset, etc all in one box. and you let the boiler adjust its temperature based on how the system is actually performing! The automatically adjustable boiler cycling under min mod levels is pretty sweet too.
The system *adjusts to what is happening*, continually. TRVs only give you flow adjustment. tN4 gives you *temperature* adjustment; the mod con can run cooler, most of the time. and if you work the distribution methods/flow rates with some intent, you can do pretty well. Maybe not true constant circulation, but you can get pretty darn close on a lot of systems, while also having an intelligent system.
That said, OR and TRVs is a fine system. It's fine for a lot of people. but indoor feedback and system integration does bring a lot to the table.
and when internet monitoring/logging becomes the norm.. ah, sweet wonder.0 -
i kind of disagree perry
the digital circuits themselves may be more complicated than analog, but they seem more stable. its easier to build stuff from off the shelf components. and then once in a digital format easier to handle and move around compared to an analog signal.0 -
sometimes
I have to disagree with the philosophical side of that argument for *most* residential heating sytems. TRV's allow the system to provide continuous, independently adjustable temperatures in each zone, or even an area of a zone. Once a comfortable adjustment has been found for each emitter, the system takes care of itself.
I view zone controls as a bit of overkill in most residential heating systems. They work, and they work very well, but the sophisticated simplicity of a constant-circulation TRV system on outdoor reset is so very close to the same thing with no wires, zone valves, transformers, thermostats, or the associated labor and material costs.
Obviously, as the zones increase in size, the need for setback in some zones and not others, or deep setback with quick recovery is needed, TRV's have met their match, and zone controls are a perfect solution. After dealing with internet controls a little, I wonder what their use really is other than as another thing to check with your email. A phone dialer with an alarm output and a contact to put the system in setback is really all that is needed.0 -
With fuel costs going where they are...
TRV's are intersting, but setback savings MUST be at the fore of any considerations lists.
Unless the house is in a warm temperate zone or an extremely well insulated structure (meaning almost new), setback is an economic necessity, not an option or a competing design with TRV's.
The integration of both is something to consider.0 -
setback
The only issue with using setback with TRV's is that it must be global. What I was thinking of was if you have a church, for example, and want to set back the sanctuary on a 7-day sechedule but keep the offices comfortable on a separate schedule, electronic controls are a necessity.
In most homes, a slight(~5°F) global setback works fine, but deep setback does not allow acceptable recovery times without a boost.0 -
Andrew,
There is no "issue" with setback. The "issue" is the lack of it - with TRV's.
Homes typically have dynamic occupant needs. Why heat a bedroom during the day?
Why heat the living room when everyone's in bed? Why heat the bedroom group of the kids, when they're off at a college dorm? At 100 bucks a pop, TRV's have a place. That "place" is with regard to balance, not primary control.
To misquote my wife, "You can never be too rich, too thin, or have too much control over the comfort of any occupied space." I see the application of TRV's as extremely narrow. We can save 100 bucks per area with HWBB. By ajusting the HWBB "blade" position, we crudely accomplish almost the same thing as a TRV. No, it won't respond to sun loading, but it won't be as ugly, prone to failure or a high initial expense either (;-o)0 -
Honestly, I personally agree with Andrew on this, in most cases. Most of my clients are building decent homes though and setback is of limited benefit for them.
The thing is, it doesn't matter what I think. I'm not the one who has to live with the system. And if the client wants to do setback, I can tell him until I am blue in the face that in their house it won't help, that they *should* find a temperature they like and forget about it.. and they won't be happy.
Furthermore, whether setback does energy savings or not, there are things TRVs and FHVs cannot do. Such as, decide to let the room temp float up a degree or so in order to keep the floor warmer and more comfortable. Or, do a shallow setback for first thing in the morning to guarantee a real run of the floor heat when people get up and take showers.
The other thing is OR dictates a water temperature I have to plan around. That's ok, it works. But it is certainly more effective for the SYSTEM to figure out what water temperature it can use at any time, regardless of solar conditions, internal heat gains, etc.
I agree with you 100% that the integration of BOTH would be FANTASTIC. And that, to some degree, is the "viessmann way"... the boiler itself watches the fluid temps and runs constant circulation headers. tN4 doesn't do this real easily though, and for it to work we would need TRVs/FHVs with overrides available I think.
But andrew, in regards to the internet thing; being able to troubleshoot without driving out to a jobsite at midnight is of no benefit?
Personally, the data logging is what excites me. I definitely look forward to having a significant number of my systems storing data for me to download and parse at will. That's going to change everything. Because we will get to see large numbers of projects and how they ACTUALLY OPERATE, ALL THE TIME, instead of how they operate while we are there, at that one house.
That can ONLY mean big, big changes, in design strategy, hardware usage, and in the nature of our discussions here online as well, IMHO. I think it will be nothing short of a revolution.
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yes
I agree, the client ultimately decides what type of control he/she wants over the heating system. I like Tekmar controls a lot, and they provide an incredible amount of control over each zone.
I have a lot to learn about the capabilities of residential internet controls. I can see where it would be valuable to have a fault code accessible via the internet. Seems like it depends a little on the cost of the control. Would analyzing data from people's homes be valuable to the homeowners? I guess it would allow more accurate adjustment of the heating curve, and your analysis of the data would certainly benefit future systems. I can see value in internet controls. I just question the direct benefit to the homeowner in terms of functionality.
Sometimes additional control is necessary, but I feel that TRV's provide adequate control for the vast majority of residential hydronic heating systems. However, they are not for every home or every homeowner.0 -
TRV Myths Debunked
Myth 1: Recovery is slow. Recovery rate with TRVs dependent upon the heating curve and size of the emitters. Both affect ALL systems with reset. Want fast recovery with TRVs? Just use a higher heating curve--at the expense of some efficiency with a mod-con.
Myth 2: TRVs are expensive. Don't forget that TRVs as typically installed offer independent control of temperature in each room or logical space. If you make an "apple-apple" comparison I can assure you will find it less expensive to use TRVs than thermostats + zone valves/circulators in each and every room/logical space. Compared to a simple single or two-zone loop system they are certainly expensive but a simple single or two-zone loop system has NOWHERE near the same level of control (or comfort).
Myth 3: You can't use setback with TRVs. POPPYCOCK!!!! There are MANY ways to use setback with TRVs!
1) CONSTANT setback of unoccupied room is as simple, easy and accurate as it gets--merely turn down the TRV. CONSTANT setback is, by the way, the most efficient form of setback! Remember--room-by-room control is inherent.
2) WHOLE HOUSE setback is just as easy. You can either use supply temperature setback (timed or constant) from the boiler itself (best) or a simple "master thermostat" scheme.
3) INDIVIDUAL DAILY setback is easy as well. You can always adjust the TRVs manually. In addition, Danfoss and I presume others offer TRV operators with AUTOMATIC, SELF-CONTAINED, TIMED SETBACK. Cost certainly rises for such, but
Myth 4: You must use either "whole house" or individual TRV setback. While TRVd systems are typically installed with all TRVs in a single two-pipe circuit, there's no requirement for such. While piping cost will rise (not much if you've used "home runs") you can easily put groups of TRVs into their own "zones". For example--you could put all of the TRVs serving the public, open space of a typical new home on one circuit with those serving private (say bedrooms/baths) room on another circuit. Each can have its own "master" thermostat. This would be a reasonably cost-effective use of the automatic setback TRV operators as you could use such only in select "private" spaces while keeping all of the "public" spaces on a separate "zone" using its' "master" thermostat for zone-wide setback.
Myth 5: TRVs are incompatible with "home automation systems". BS! You just have to think a bit differently. Instead of tying a bunch of thermostats together into a centralized controller all you have to do is "fool" the TRV operators. How do you "fool" a TRV operator. Simple. Use a remote-sensing operator. Install an X-10 (or similar) "thermostat setback" device underneath the remote sensor. Such device merely produces a bit of heat electrically to "fool" the sensor into thinking that the room is warmer than it actually is. (Danfoss used to make a TRV operator with this built-in ability--I have them--but they're no longer available).
All this said, if occupants allow TRVs to "do their thing", constantly set back unoccupied spaces, and adjust the TRVs for comfort and use of the space--NOT BY A THERMOMETER--I suspect they'll there's no reason (including fuel savings) for daily setback.0 -
TRV's
I'm glad someone else said to turn the heating curve a little higher than it needs to be. I was afraid I would be burned at the stake if I suggested that. ;-)
I was unaware of programmable TRV's. Every time I go to the Danfoss website, I feel like Jack Torrance carrying an axe through a frozen hedge maze. Do you have a link, Mike?
The home automation thing sounds a little inexact and strange to me. Does it work ok?0 -
calm down mike
I know you like TRV's, but realy what is this business of fooling them with little heat tape devices. I thought this was a keep it simple analog vs. digital debate? this is sounding a bit complicated. Are you so stuck on the analog side of this that your willing to come up with silly solutions like this. Granted flow modulation at individual emitters is a very elegant means of fine tuning indoor temperature control. But do we really want to run our curves too high to allow for fast recovery of deep setback areas? I think not. Maybe we don't really need deep setback, but if we believe we do Digital controls are superior in this regard. The question of wether this level of control is necessary is separate from how best to accomplish it.0 -
And another benefit to #1
Myth 1: Recovery is slow.
The rate doesn't start to slow until it needs to start to slow which greatly dampens any internal temperature over or under shoots. It's like a high end elevator that you can't feel going up or down yet doesn't take much longer to change floors. The flow is slowly choked. I'm very envious of the near fully TRVd system - would love to have it with a manifold setup.0 -
Actually...
I'd recommend flattening the curve a bit but raising so that it still has the same top end. The kind of curve you have for full outdoor reset at milder temps is so low that 5 or 10° won't do much for any recovery. Smaller engine same mass.0 -
Nothing will dampen my enthusiasm for TRVs.
When I set out to make the "best heating system possible" for my old house I initially had lots of wall thermostats and zone valves in mind. Thanks to DAN and his books, I discovered TRVs (even if he says, "Why don't more people use them?" Good Question.)
STILL skeptical I ordered the "special" Danfoss TRV actuators with automatic setback ability. Literally a tiny heating pad connected to the remote sensor. Three levels of setback available via a center-tapped "heating pad" and three wires.
Paid dearly for them and waited for MONTHS to receive as they had to be special ordered from Denmark.
While I've yet to implement the whole-house automation system--including ALL SORTS OF SETBACK--the wires are all in place and the designs are made.
BUT, after living with the TRVs for about 6 years now I find almost no need for the automation. Granted it will be easier to hit the "away" button in a room (or for the house as a whole) but I can do the same thing manually. The ability to put a bedroom into the minimum setback on a timed schedule might be useful, but I've honestly found that I can keep the bedrooms perfect for sleeping with flannel sheets and a light down comforter and walk into bathrooms with heated floors that just get warmer the colder the weather.
All of this occurs automatically and if I use a barely adequate heating curve I find that the house may cool 4-5 degrees on a cold, clear night but the baths are still relatively warm.
In other words I set out to build a complicated TRVd system and find almost no need for the complication--the TRVs just do it themselves. Of course my oversized standing iron rads have much to do with this as well...
I'm reminded of an old Doris Day song, Anything You Can Do I Can Do Better. For the same level of general control I firmly believe such for TRVs/FHVs compared to digital control.0 -
But Mark, the $64,000.00 question is???????????????????
Will a nuetered mutt still attempt to do this? I guess it depends when he was de-nutted huh? Mad Dog
To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"0 -
uh huh...................
The absolute crap that passes for "music" today is sad. Don't even get me goin' on Rap and Hip-Hop. Deep Purple - Made in Japan on 8-track!!!!!! Mad Dog
To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"0 -
I imagine youve
all heard this, but i always thought it was funny so...
These two guys were watching this big black dog licking it's nards.
The one guy says to the other,"I wish I could do that."
The other guy says,"Well, maybe if you pet him, he'll let you."0 -
Ken,
TRVs don't have to be $100 apiece, for one.
For two, setbacks sacrifice the very comfort you are talking about, to a large degree. MRT matters, and it doesn't recover quickly from setbacks.0 -
but Mike, with Tn4 you DON'T HAVE TO SET THE CURVE HIGHER.
The system will ramp up water temperatures just to recover from the setback quickly. It will then settle the temps back down to the minimum the system can use.. lower than any curve you would ever set in any home other than your own.
Yes, you can work around all that stuff, but tN4 makes it so you can do so with no sacrifices and with pretty simple operation. and again, most of your arguements rely on an owner learning how their system works and working around the limitations of the system. tN4 instead works around the owners and does what it's supposed to in spite of them.
TRVs have their place, but none of these arguements are anything new really. The fact is they require more involvement from the owners if variability is desired (and lords knows, I try to squash the desire, but it is what it is) and they do not offer the integrated, informational packages that more modern controls can offer. EVEN IF they are technically superior.
What is needed is a modern TRV that has analog action with digital override capabilities, IMHO.0 -
Digital...Analog
My controls professor told us that digital is just an approximation of analog. Where a true proportional analog curve is approximated by digital points. When to use one or the other depends upon the application.
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internet controls for homeowners is certainly of limited value to most homeowners, UNLESS it means that YOU, as the pro, get to keep closer tabs on their system and make sure they are operating at peak efficiencies. I could see service contracts getting a lot more interesting. How impressed will the homeowner be when you give them a call one day and ask them to nudge a dial somewhere because you noticed the system was cycling a little more than you wanted? Or you show up with a replacement valve head one day before they even realize their guest bedroom zone isn't heating properly?
Personally though, I'm considering sending these things out for free just as information gathering tools for myself. Well, maybe not free
but the data I hunger for, hunger deeply!!! 0 -
Analog is simplier, more stable - and parts are off the shelf
Electronic Analog control circuits are much simplier by a factor of at least 10,000 than any digital control circuit - and don't require any programing. The parts are redily available from any electronic parts supplier. Most analog controllers can be built with a simple "op-amp" chip some resisters and perhaps a capacitor - with a power supply (or if you really want to go basic - all you need is a transister or two, and a few resisters and capacitors for many circuits: an "Op-Amp is only a preassembled set of 3 to 8 transisters with a few resisters in a single small chip). That will have feedback and often feedforward functions. My guess is that outside of the power supply - that most analog controllers can be built with about $10 of parts plus whatever sensors are needed for the system.
The only disadvantage of them is that they are designed for only a single application; and will not work for any other application. All design cost and production cost then are often for only a few controllers - which in many cases makes them more expensive than a digital controller that can be programmed to do adequatly control hundreds of different processes and can be mass produced and sold as a general item.
The other problem is that few people these days are learning how they work and don't even know how to design one because most people are being taught only about digital controllers.
Kinda like Vacuum tubes. No one is required anymore to take a class on how vacuum tubes work. Yet vacuum tubes do things that electronics cannot yet do (or cannot do good enough) and are still about a billion dollar a year world wide market that is currently growing.
At least when I was in college analog control courses were still required for all mechanical and electrical engineers. Now I think it is only an optional course for someone specializing in control technology. A real shame. All digital does is mimic what an analog circuit does; which works well for many applications; but does not work for all applications.
I assure you that analog control circuits will always exist for two reasons: 1) If you are actually mass producing an item they are far cheaper to build than a digital controller. 2) They do things that digital controllers will never be able to do on the extreem ends of things because digital controllers are limited by sample rates and measurment increments.
I do admit that for a person buying a controller that buying preassembled digital controllers is simple and most people know how to program them for most functions.
Perry0 -
Tracking
I agree, the overall benefit from tracking the performance of people's homes is very valuable. As far as I know, not much real-world tracking of this kind has been done. My guess is that it would clearly indicate that we are oversizing boilers most of the time.
What internet controls are best for residential systems right now? Is Tekmar introducing their tN4 internet connection soon?0 -
Here's the link to Danfoss Programmable TRV Operators
Forgot that links to specific product lines don't work at the Danfoss Website. First click on "Radiator Sensors" (top-left), then on "Programmable Sensors" (bottom-left).
The setback operators I have are different--no built-in timer, but three different setback levels depending on how you connect 24VAC to two of the three terminals.0 -
Must agree that automatic feedback of "user desire" would be a nice addition to a TRVd system. While I'm almost certain such can be done with little more than three temp sensors and programming (of course), I don't believe that anyone has done it yet. Closest I know of is the Buderus GB using the RC-10 controller.
After running for nearly two complete heating seasons without coding changes to the heating curve on my Vitodens I did conduct one "response test" this past season. During a period of true boiler modulation (temp in the 20s), I opened a number of TRVs wide and raised the sun dial setting 10F to 75F. Boiler input barely (by ear) increased and supply temperature began a slow rise to the new target. After about 20 minutes--and very little "additional" heat from the rads--I hit the "Party" button. Boiler immediately jumped significantly in output and the rads heated very rapidly.
In previous response tests with a significantly higher boiler curve (first heating season), merely opening a number of TRVs wide was enough to cause a significant increase in boiler input and if I actually increased the sun dial setting it would really increase.
It was almost as if Comfortrol had "learned" that my general desire was for highest efficiency and slow response and was saying, "Hey dummy! You can't trick me into inefficiency just by raising the sun dial! That's why we included the 'party' button!"0 -
"early next year". grumble grumble...0 -
By next heating season I might have a website with real-time system operating conditions. Have to refresh my computer programming back to the "old days" to directly communicate with my datalogging system. The software supplied with the computer interface does not allow automatic data updates--you have to do so manually. It's been a LONG time since I wrote a program to directly communicate with a serial device but surely it will come back easily...0 -
Obviously
beautiful work...
Would you mind explaining to a dumb ol guy who isn't up to snuff, exactly what he's looking at?... several pumps...valved, a manifold. What kind of connections are on there? what's the blue thing? What are the valves that appear to be capped? ...air bleeders?... how'd you do the crossovers on the manifold?....
What I'd like to do is encourage you to explain your artwork, so I can try to learn what you did here and why.
Plus, I liked what you said in your post.0 -
not talking apples to apples perry
surely you agree "that depends"........
different control systems have different requirements.
if you are talking discrete analog vs discrete building of digital circuits I'd agree digital is more complicated.
but build an analog AND OR NOR circuit, which is simplier analog or digital? see it "depends"
by the way, I worked a lot with both, they have their places, also used 30,000watt vacuum tubes..0
This discussion has been closed.
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