I have a new house - On line between zone 4 & 5. ICF foundation, R35 walls, R60 roof, airsealed compulsively. Basement is unfinished with slab over 4" of EPS with radiant tubing First floor is a 3 1/2" slab on metal deck and bar joists, insualted with embedded tubing. Second floor is wood with tubing above subfloor and 1 1/2" gypcrete cover. Zones are set up as follows: Basement is one zone of 3 loops, First floor is mostly open living/dining/kitchen plus one bedroom/bath. Bedroom/bath is one zone of one loop. Rest of first floor is one zone of four loops. Second floor is three bedrooms (one a master bed/bath) and a shared bath. Master bed/bath is one zone of one loop, Smallest bedroom and shared bath are one zone with one loop and remaining bedroom is one zone of one loop. So six zones, eleven loops - all 1/2" pex, longest loop is about 225' including insulated leads to manifold. Question is what is the best way to layout the manifolds and pump(s). One option is using a single pump and zone valves but I am confused about sizing the pump. Would it be sized for serving 11 loops at once? Wouldn't this be WAY over pumping if just the single bedroom of one loop was calling for heat? The other option would be a pump for each zone - is this typically done? I am in a location with VERY high electric rates ($0.58/kWh!!) so I'd like to keep pump efficiency as high as possible. Would the control wiring for a 6 zone system with 6 pumps simply be a 6 zone pump relay? Would the pumps be on the return side of each zone? Is the best piping layout a separate supply and return manifold for each multi loop zone? I assume the multi loop manifold should have balancing valves to balance the loops. Would the single loop zones simply be piped directly. The boiler is a Lochinvar Knight propane boiler also tied to an indirect water heater. (and yes, I did room by room heat loss calcs ) Any guidance would be appreciated!

We have a product that speaks to what you are doing.
It is a zone valve manifold coupled with a Grundfos Alpha pump.
We call it the Dominator zone valve panel.
The ECM pump modulates based on pressure so it will flow based on need, set it on AUTO and forget it.
Yes pump would be sized to meet flow if all loops are open. As I said it will automatically balance flow based on circuit open.
Link to part: http://www.blueridgecompany.com/radiant/hydronic/780/rht-prefabricated-dominator-zone-valve-panel
This will give you an idea about how, were you to use this type of system it is set up.
Dan

I'll let the pros sort out the hydronic details...

Block Island, right?  What ever happened to the underwater cable to the RI grid and offshore wind plans- I thought they were still going forward with both?

The combined lifecycle cost of PV + battery is now considerably less than $0.58/kwh, but it's a steep upfront charge:

http://www.rmi.org/electricity_grid_defection



Even simpler grid-attached PV would be well worth it if standard net metering rules apply. I believe they still do, though the 3% of peak net metering cap BIBCo has in place is a bit on the stingy side, given that even 25% PV has been shown to not create grid instability or other problems (other than a revenue problem for the utility). If the 3% of grid peak has already been installed on Block Island (and it might have), outright grid defection may still be a reasonable option.  By RMI's projections (which are if anything conservative), grid defection will cost about half BIPCo's per-kwh rate on a lifecycle basis by 2020.

I thought the wind farm fell through.... Chris

Nope. Dana is right. Deepwater Wind is going ahead and has start construction on the turbine foundations. Scheduled to "flip the switch" in late 2016 as the first offshore wind farm in the US. Cape Wind, however is dead as a mackerel. The bad news is that much is still up in the air as far as us island rate payers go post 2016. Best info is we will have a power cost reduction of about 40% So $0.58 down to the $0.38 to $0.40 range - better, but nowhere near mainland so electricity is still an issue. It is also VERY unclear what the status of net metering will be post cable to the mainland. Currently, Block Island Power Co. is exempt from having to provide net metering. As BIPCo will remain the power distributor (but not the generator) it is unclear what will happen there - stay tuned. In any event the smallest town in the smallest state is about to break the seal on US offshore wind power. Kinda cool. By the way Dana - good memory!!

As Dan indicated, you should shop for an ECM or PMM type pump design. The Grundfos Alpha, Taco Bumble Bee and Wilco ECO variable speed pumps are quite popular. We prefer the Grundfos as it operates more quietly and has been more reliable for us.

Grundfos Alpha Pump

I don’t know the basis of you HR system design, but a single pump and a single supply temp is often possible and is always preferable whenever possible. The manifold and distribution plumbing options are well addressed in John Siegenthaler’s “Modern Hydronic Heating”.

Posted By sailawayrb on 01 May 2015 10:45 PM
As Dan indicated, you should shop for an ECM or PMM pump. The Grundfos Alpha, Taco Bumble Bee and Wilco ECO variable speed pumps are quite popular. We prefer the Grundfos as it operates more quietly and has been more reliable for us.

Grundfos Alpha Pump

I don’t know the basis of you HR system design, but a single pump and a single supply temp is often possible and is always preferable whenever possible. The manifold and distribution plumbing options are well addressed in John Siegenthaler’s “Modern Hydronic Heating”.

Grundfos makes the best well water pumps also. Denmark is the country it was founded in.

Seems like Europeans sometimes have the edge on us when it comes to energy efficient products. I believe in Germany the kWh rate is around 0.45 cents which makes electricity quite expensive, therefore the need to build more energy efficient homes and buildings.

SIGA building tapes and membranes are out of Switzerland as is the Swiss Warm Edge Spacer for triple pane windows.

I have looked at the Grundfos Alpha and that seems like a great option. (already have Grundfos boiler system pump and Indirect Water Heater loop pump - Well has a Grundfos SQE constant pressure system too - I like them all!)

Posted By Birdman on 01 May 2015 09:08 PM
Nope. Dana is right. Deepwater Wind is going ahead and has start construction on the turbine foundations. Scheduled to "flip the switch" in late 2016 as the first offshore wind farm in the US. Cape Wind, however is dead as a mackerel. The bad news is that much is still up in the air as far as us island rate payers go post 2016. Best info is we will have a power cost reduction of about 40% So $0.58 down to the $0.38 to $0.40 range - better, but nowhere near mainland so electricity is still an issue. It is also VERY unclear what the status of net metering will be post cable to the mainland. Currently, Block Island Power Co. is exempt from having to provide net metering. As BIPCo will remain the power distributor (but not the generator) it is unclear what will happen there - stay tuned. In any event the smallest town in the smallest state is about to break the seal on US offshore wind power. Kinda cool. By the way Dana - good memory!!

Note, in the RMI analysis of several months ago, 38-40 cents is the price point at which battery + PV had economic legs even BEFORE Tesla set a price point on the battery end of it that undercut the industry by 2/3.  That moves you quite a bit to the rigth on that graph I posted.

In an interview over the weekend Lyndon Rive of SolarCity let slip that by 2016  in Hawaii SolarCity will be offering $0 down lease options with PV + Tesla batteries in 2016 that will beat the utility retail prices.  In the same interview he talked about having he hooks that would let the utility control the battery for grid stability, paying the PV + battery owner for that use, which would make it an even better deal for other ratepayers as well as the owner, but would also have the capability of unplugging.

This is a direct shot across the bow of the distributed utilities that would penalize PV owners with connection fees, etc., since the clear threat is that if the utility demands are abusive of the distributed power asset owners, people have the option of outright grid defection.

The retail cost of grid power in Hawaii right now is about 31 cents, about half the going rate on Block Island, and still well below the projected price point after the offshore wind project is completed.  It would take about 2x the amount of PV in RI to defect from the grid than in HI, but the size of the battery requirements wouldn't have the same multiplier.  Short of grid defection, the size of the resources to get pretty close to net-zero while remaining hooked up to BIPCo is even smaller, and financed over 20 years would be cheaper than paying BIPCo monthly (at either the current or projected rates.)  It's possible that BIPCo would hang some ridiculous connection charges on you if you're hooked up but using only 10s of kwh/month, and never exporting power to their grid, but they also might not.  It's worth starting the dialog with SolarCity (provided they'll talk to you just yet)- they're betting they can beat 58 cents by better than half if they can afford to lease systems and beat Hawaii's grid price with a large enough margin to attract customers. 

It might even be worth trying to get the attention of someone within the electricity policy group at RMI, since island grids serving fairly well-off population that has good credit/deep-pockets can be a good test-bed for distributed micro-grids. They might be able to steer you to other resources.  The arbitrage between sub-30 cent LCOE distributed PV + battery power and 38-58 cent grid power could be pretty attractive to micro-grid developers, even if it is the smallest town in Rhode Island.