System Design #1 Crested Butte, Co

billyboy

Something like this

njtommy

Thats looks like a nice project.

Harvey Ramer

For proper operation of the Thermomix valve, P1 will have to be relocated to a position between the valve and the boiler return. Pumping into the boiler.

Zman

I really don't see the need for P1, the mixing valve, P7,P8,P9 or P10.
If you use a tekmar 356 to control P4, you won't have a boiler condensation issue unless you have mis sized the DHW heat exchanger.
You don't need zone valves and zone circs. It is just a waste of money.
As far as back feeding the electric heater in case of emergency, you could pipe it as a bypass if needed. How does the rest of Crested Butte survive?

Harvey Ramer

Zman is right. A lot of extra components there.

Personally I would let the thermomix in due to the way the buffer tank is piped on the return and considering the fact that you have in-slab radiant.

Zman

Harvey Ramer said:

Zman is right. A lot of extra components there.

Personally I would let the thermomix in due to the way the buffer tank is piped on the return and considering the fact that you have in-slab radiant.

There is obviously more than one way to go about this one.
I have had good luck with the 356 because it has a sensor on the boiler return that adjusts the mix when temps drop.

If we had more info on the radiant loops and their lengths, it would help size P6.
One alpha is usually more than enough for an entire residential system.

hot_rod

we need more info, like what GPM for the zones and supply temperature for the zones on design day.

If that is a non- con, why not just pipe direct to the buffer, run it at 160F, and generate DHW via a plate HX. Mix the radiant supplies via a tekmar from the buffer.

If all the radiant zones are within 10- 12 degrees of one another, one temperature mix is fine.

Could be done with 3 pumps and 4 zone valves.

billyboy

Harvey, yes, thanks, I didn't look at the Caleffi installation insrtuctions:
http://s3.supplyhouse.com/product_files/280Install.pdf

I assumed it could be installed like Dunfoss Thermic valve, bottom of page 3:
http://s3.supplyhouse.com/product_files/193B1701-Submittal.pdf

billyboy

P7, P8, P9, P10 Grundfos Alpha's in low Fixed Speed, provide constant circulation within each of the 4 zones, in heating season.

P6 Taco Viridian, in Proportional/Variable Pressure Mode (low)
Provides flow into the zones when Nest thermostat opens any zone valve, in heating season.

All 5 pumps above can be turned on/off via an internet switch (Wemo), at start/end of heating season.

billyboy

HR
" If that is a non- con, why not just pipe direct to the buffer, run it at 160F, and generate DHW via a plate HX. "

I'm thinking about doing that & I started a thread on that topic.

billyboy

On studying the Tekmar 356 installation instructions, it says:

Boiler sensor placement for boiler protection, on either boiler supply OR boiler return:

"If this mode of operation is selected, the boiler pump should operate continuously"

I don't want this, I prefer the simple Caleffi ThermoMix.

billyboy

billyboy said:

Motive for piping this way is partly due to sketchy history of NG service in Crested Butte.

If boiler or NG kraps out, I want to be able to keep pipes from freezing using the 22,500 BTU electric elements in the 50 gal. State Commercial Sandblaster water heater tank.

This tank will normally be heated from the boiler via a FPHX but in an emergency heat can be put into system.

Say the Winter low temps set the 1,000 yr record -50* or so, the 22,500 BTU's would be added to the boiler 85,000 BTU output.

I know that I could elemonate a pump by combining P1 & P2 function by using a manual bypass valve at boiler, but I already have a couple Taco 006's & would like for the DHW tanks 22,500BTU electric coil to add heat to the system automatically.

hot_rod

I think the control logic will become a big challenge. Suppose a low heat or no heat condition, you want to load up the buffer tank. Somehow, say for instance a no heat call condition, you will need to call on P1 boiler pump, P2 primary loop pump, and P4 buffer tank pump. Also boiler call for heat at TT.
What control will do that and where will you locate the sensor in the BT tank?

At other conditions you only need P1 and P2, DHW for example. You may need some double throw relays to lock out certain pumps when others call.

Same when you have the electric element heating the tank, you would not want to run P1 under those conditions. no reason to put electrically heated water in a boiler that "becomes" a cooling tower when the burner is off.

Eventually the buffer tank will warm and stratify, slowly with your piping. I think you would accomplish that faster is the S&R were at top and bottom, not both at the bottom? I think loading BT with your piping may cause the boiler to short cycle as a slow thermosiphon will not keep up with the boilers output. A tee, valve and a few feet of pipe could give you the option to flow top and bottom.

billyboy

HR, thanks for the help.

"What control will do that and where will you locate the sensor in the BT tank?"

Tekmar 256 ODR
Sensor location, I'm undecided between using the tank well above my proposed Hot inlet

OR placing it at the top of BT on the system supply outlet?

As for:
" Somehow, say for instance a no heat call condition, you will need to call on P1 boiler pump, P2 primary loop pump, and P4 buffer tank pump. Also boiler call for heat at TT."

&

"At other conditions you only need P1 and P2, DHW"

Not a problem, I'm good with relay control design. I was a hardware Field Engineer with IBM for 10 years back in the 60's then went into microcode diagnostic self tests for 20 yrs.

" I think you would accomplish that faster is the S&R were at top and bottom, not both at the bottom? "

Could be, I think Rheem put those 2 x 2" ports there for this purpose. Not that that means alot to me.

I have been thinking about how to use this tank as suggested by Idronics 17 as a 2 port BT.

The only issue is adding a 90* elbow into the top 2" port, as to act like a side of tank port, to reduce mixing.

I could weld a thin wall steel pipe 1-1/2" elbow into tank side of a 2" x 1-1/2" Black Hexagon Bushing.

billyboy

Or 1-3/4" OD

http://www.ebay.com/itm/1-75-44mm-OD-90-Degree-Elbow-Stainless-Steel-Wastegate-Dump-Valve-Pipe-1-3-4-/171878085981?hash=item2804bb755d&vxp=mtr

billyboy

This boiler has seperate system & DHW tt inputs & seperate 120VAC outputs

Zman

billyboy said:

P7, P8, P9, P10 Grundfos Alpha's in low Fixed Speed, provide constant circulation within each of the 4 zones, in heating season.

P6 Taco Viridian, in Proportional/Variable Pressure Mode (low)
Provides flow into the zones when Nest thermostat opens any zone valve, in heating season.

All 5 pumps above can be turned on/off via an internet switch (Wemo), at start/end of heating season.

I am realizing that one of the goals of this design is to give you something complex to control.
My point is that there is absolutely no reason for this many parts on the distribution side.
You either need just P6 and the zone valves OR P7-P10 without the zone valves and P6.
You are adding over $1,000 just in parts that serve no function and waste electricity.

hot_rod

billyboy said:

HR, thanks for the help.

"What control will do that and where will you locate the sensor in the BT tank?"

Tekmar 256 ODR
Sensor location, I'm undecided between using the tank well above my proposed Hot inlet

OR placing it at the top of BT on the system supply outlet?

As for:
" Somehow, say for instance a no heat call condition, you will need to call on P1 boiler pump, P2 primary loop pump, and P4 buffer tank pump. Also boiler call for heat at TT."

&

"At other conditions you only need P1 and P2, DHW"

Not a problem, I'm good with relay control design. I was a hardware Field Engineer with IBM for 10 years back in the 60's then went into microcode diagnostic self tests for 20 yrs.

" I think you would accomplish that faster is the S&R were at top and bottom, not both at the bottom? "

Could be, I think Rheem put those 2 x 2" ports there for this purpose. Not that that means alot to me.

I have been thinking about how to use this tank as suggested by Idronics 17 as a 2 port BT.

The only issue is adding a 90* elbow into the top 2" port, as to act like a side of tank port, to reduce mixing.

I could weld a thin wall steel pipe 1-1/2" elbow into tank side of a 2" x 1-1/2" Black Hexagon Bushing.

I was going to suggest someone like Kurt (SWEI) to build a PLC. Sounds like you have that skill.

Once you have you piping decided, sit down and write an essay of how the various pumps need to be controlled and when. A custom control seems to be the best way to control this much stuff.

It would take a bushel basket full of off the shelf parts to wire and control that and have them all communicate properly.

I still haven't heard what supply temperatures are required for the zones. If it is a wide spread, more than 15°, then you may need multiple mixing devices.

As for that Rheem tank, those are designed to be DHW storage connected to large copper tube boilers, or some other batch type DHW boiler. With 35- 40 gpm flow into them they mix well. It seems like your flow might be in the range of 8 gpm? That will not stir the tank like a 40 gpm flow

A large tank, with large ports closely spaced like that will tend to act more like a hydro separator, not a stratifying buffer tank, me thinks.

billyboy

Zman:

"I am realizing that one of the goals of this design is to give you something complex to control.
My point is that there is absolutely no reason for this many parts on the distribution side.
You either need just P6 and the zone valves OR P7-P10 without the zone valves and P6.
You are adding over $1,000 just in parts that serve no function and waste electricity."

YES, all zones require the same temperature.

Please show me a simpler system side diagram that has:
1. 4 independant zones with continuous circulation within each.
2. 4 independant zones with 4 thermostats that control heat within each.
3. That uses less electrical power.
4. That uses less than 5 pumps.

hot_rod

If you use an outdoor reset control, and take the time to dial it in properly, you will get darn near constant circulation. that could help eliminate the complexity.

One Alpha pump off the BT controlled by ODR.

Be aware also those Nest stats suck huge current draw when they go into battery recharge. If you try to connect them with common hydronic relay boards, one or two is all you can run. be sure to include enough transformer power to run all the stars and valves.

What about this?

Use one tank as the buffer and DHW generator. Either direct DHW via the plate, or add a tank after the plate for additional storage.

Is there a need to store energy in two tanks? A huge dump load DHW for example? With this you have essentially 120 gallons of DHW stored, and whatever the boiler can generate on priority. In your area with cold mountain water and that boiler maybe 2- 2.5 gym continuous.

The Caleffi ThermCon tank has seven 2" ports, use one and add whatever KW element you want. I have found up to 9KW can screw into a 2" port. Heatco Chromolox, Wattco are some brands of UL listed immersion element and control.

The heat loads are pulled off via an ODR device, tekmar controlled. Could be a motorized 4 way, 3 way, injection, or ?? Kurt has a method for dialing in ODR to get virtually constant circ.

This eliminates one tank and the associated jacket loss. The Caleffi ThermCon has a full 2" of foam injected around the entire tank, very low loss. Throw a WH blanket around it for even less loss.

This gets it down to 3 pumps, or 4 if you add DHW storage tank with the plate hx.

Zman

Hot Rod's drawing in the above post looks good to me.

billyboy

HR, you make alot of good points. I like the 1 tank idea.

The zones need 150* water at design -20*

I have used Nest thermostats, my has Son also & now requires them, he owns 2 Apple repair shops. Nest was started by X-Apple people.

I have done constant circulation & like it.
I don't believe bang/bang is better or saves money.

My distribution design is not complicated, but does require 5 ECM pumps on low power.

I have the 3-port Rheem ST120 tank & am using it.

With the Taco 008VDT & sensors set at 5* DT , I think that any delay will be short.

The FPHX will stay hot due to the 008VDT pumping slow using 63 milliamps constantly, that should keep up with the recirculation needs without kicking full on until needed.

With the tank kept at 160* the FPHX will keep up with demand.

Note that I have included a Ecosmart ECO 24 24 KW at 240-Volt Electric Tankless Water Heater as backup.

billyboy

The recirculation will mix the tank.

4Johnpipe

What is your heating load? You can use this...
http://www.htproducts.com/versahydro.html

hot_rod

I'm still wondering why you would not use the Rheem tank as just a two port, upper and lowest port, put a diffuser tube in the top if it is a top connection.

A double tapped bushing works nicely for adding a capped diffuser tube.

It's rare to see a Euro designed tank with top or bottom connections, they generally use side ports for all the ins and outs, some with heat trapper tubes on them. top connections promote thermosiphoning if the loads are above the tank. gravity gates, or check valves would be needed to get 100% flow stop age.

True ODR is not a bang/ bang control. Properly used the system should start to ramp when outdoor temperatures drop to 68°F and run continuously from that point on. Another nice option is indoor feedback to the system, that is possible with tekmar. Really the heating system needs to know what is happening indoors, temperature wise, as much or more than outdoors.

I have it from pretty reliable sources that some of the engineers N hired away from Honeywell are not so happy with the direction of then product. Something about emphasis on the wow factor but not the actual operation and compatibility with the old and new systems it is being installed on. The classic marketing vs engineering snafu. But you know what they say about rumors.

billyboy

HR,

As I said, the DHW recirculation will mix the BT, so stratification is wishful thinking.

With the Taco 008VDT ideling (heat request jumpered on) waiting for S1 to become 5*, or more, cooler than S2, it runs slow at 63 milliamps (7.6 W)

No one has mentioned a diffuser tube, sounds like a good idea,
I dronics 17 refers to tank built in diffuser plates. No hits on heatinghelp & google no help.

I think that I could fabricate one.

The BT top port is in the center as I have drawn it.

I got 1 hit on ebay "double tapped bushing" but center hole is only 3/4"

"True ODR is not a bang/ bang control" I didn't say it was.
I thought bang/bang refered to stopping & starting flow, which is what would happen when having 1 DP pump & 4x zone valves.

As far as setting ODR "tight" so as to get near continuous circulation, with a sudden large outside temp. drop, the house could be uncomfortable for many hours, not an option.

ODR is far from perfect, a sensor outside does not come close, in many cases to accurately predicting what the system water temp. needs to be. As you said, indoor feedback is needed.

I am pretty familar with ODR, having messed with several boilers that have it.

I have designed, coded, & debugged a nice little Arduino (microcomputer) based ODR controller, it uses 10K NTC thermistors & pots (potentiometers) to set the 4 perameters that set the ODR end points.

billyboy

My Son don't want my "Arduino solution" in his house, only off the shelf available replacable units.

billyboy

4johnpipe, HTP, never again.
I have nursed along a HTP Voyager for 11 years, ignitors, LOUD blower, fail to fire, etc. etc.

billyboy

As M.E. has said: ODR is incomplete unlkess it can take into account: Wind & cold clear winter night radiant cooling to space.

billyboy

Google has bought Nest at a VERY high price. I suspect to spy on home owners.

hot_rod

I get the doubled tapped bushings from OEM, now owned by Beckett.

I think a spare tube is one option. This is an old Lochinvar tank I cut open and it had the spare tube already installed. It's build like a typical WH dip tube, poly plastic inserted into the 2" gal nipple. The end is melted shut. I would imagine any tank manufacturer could supply that spare nipple. I think Precision is the company that makes those and also dielectric nipples.

Fairly easy to build a tube with an ell, or a cap and a bunch of holes drilled in the appropriate spots.

A 2X 1-1/4 double tapped bushing should offer plenty of flow for that size system 8-9 GPM?

As for stratification, if the DHW HX pump is not running, there should be no mixing in the tank. Maybe evening hours the tank could stratify and store some additional energy.

Sounds like you have a handle on the control you want. For your own use that is fine, trying to sell that much componentery and control to customers is a tough go. Don't want the controls to cost more than the rest of the system

hot_rod

billyboy said:

As M.E. has said: ODR is incomplete unlkess it can take into account: Wind & cold clear winter night radiant cooling to space.

At some point I think you can over think or over build a simple thermostat control system. Unless you have a huge mass in the system, or undersized boiler the dry or low mass systems respond within minutes to a heat call. My ceiling radiant warms within 15 minutes of start up, if we set it back during the day.

High mass systems have enough flywheel to smooth out some minor temperature or load changes. Ramping down, that is where indoor and outdoor have more value in my mind, controlling over-shoot. Or sudden and large indoor condition changes, like public spaces, churches are a classic example of a large, sudden indoor condition change, not a great place for high mass systems.

I have an Ecobee on my shop and it watches several weather stations in an effort to "predict" what is headed my way and respond. But still, it's the indoor temperature that defines my comfort level. No doubt outdoor conditions influence indoor conditions. For me it's a 6 foot diameter space around the easy chair, or in the bedroom that I want controlled accurately.

At the end of the day the home or building owner gets to define "ideal" comfort.

billyboy

http://www.pmmag.com/articles/88410-zoning-with-constant-circulation-br-john-siegenthaler?v=preview

hot_rod

While the concept is unchanged, keep in mind that article is 12 years old! Much before we had smart "delta pumps", boilers that have a lot of intelligence built into their controls, and thermostats that learn and adjust your system for you.

Sounds like what you really want is a TRV controlled system. non-electric, proportional control with flow regulation available

billyboy

1 tank

billyboy

So is bang/bang preferred by some because it's cheaper OR because it's better ?

billyboy

I have read the Euro's really don't like bang/bang, perhaps they are behind the curce & need better engineers.

billyboy

curve

hot_rod

I'd guess 80- 90% of Europe zones with TRVs. That is all you see when you visit jobsites, new and old buildings. TRVs play SO well with smart pumps, especially ∆T circulators.

Not a lot of zone pumping in Europe, other than commercial jobs.

There are 10 or more big name TRV manufacturers in Europe, must be millions produced yearly. I had that figure once upon a time.

Zman

So what does this do that the 3 circ option Hotrod posted above doesn't? Except cost a lot more?

billyboy

I don't like glycol.

This house is being built in climate zone 7, as is most of Alaska.

The 2 rooms above the garage (1 zone) can be exposed to -25* on all 6 sides. The floor is over unheated garage, so it won't be quite as cold underneath.

With bang/bang & centrally located thermostat set back to 60* I'm afraid that some perimeter pipe may freeze.

I prefer continuous circulation to bang/bang.

billyboy said:

Zman:
Please show me a simpler system side diagram that has:
1. 4 independant zones with continuous circulation within each.
2. 4 independant zones with 4 thermostats that control heat within each.
3. That uses less electrical power.
4. That uses less than 5 pumps.