advice for a NJ multifamily

Osborn

I own a vacant four apt building and am trying to put together an efficient h20 central heating solution.  The apartments (near nyc) are about  900sf each, have one bath, and are well insulated.  (The building has two ground floor stores.  I'll probably do hvac for those..)



For the apts, I'm looking at some kind of high eff. boiler and indirect water heater routed to 4 zones.  Can folks offer me thoughts about the ideal water temp, baseboard, radiator, configuration, and tank sizing?  180 baseboard seems like the standard operating proceedure to the installers I've talked to so far.  In floor radiant is not practical.



Initially I was also looking at a solar array on the roof as a hot water and perhaps heating supplement.   An installer suggested a 6 unit array, for about 20K.  At 10% help to heat that seems unrealistic...($12-1300 year savings at best..?)

Steamhead

First off

what type of system is there now? 

Osborn

jersey four family

There's no heating at all... a gut.  

Tim McElwain

Are you looking to

have individual boilers or one boiler?



Do you want a conventional or Modulating/Condensing package?



You can have the Mod/Con with baseboard if you use outdoor reset and enough baseboard to be able to run it at lower temperatures.

Osborn

mod / con low temp ...

Well, as I'm interested in environmental conservation and will be paying for heat, I want to go for the most efficient possible up front.    I'm thinking that water should come back to the boiler around 125 or less to keep it in condensing mode...   There will be at least 4 900sq ft zones; originally i wanted to separate the bedrooms, for a more intelligent approach, but don't know if tenants would really mess with the thermostats.  I've calculated the heat loss to be about 20k/btu for the 2 larger apt (higher ceilings) and 15k/btu for the smaller.



I do have the ceilings in the apartment open and I thought about diy in-ceiling radiant, but the upper apartment has 15 foot ceilings and the lower 10ft... I also had the thought to try to get radiant to both apartments by firing up the 1st floor ceiling to provide radiant ceiling to the first floor and radiant floor for the second floor.  But that's probly madness!!



I wanted to try to do a solar assist, but I'm told the most I should go for is about 10-15% of heating, which doesn't seem worth the 30k or so.  the dhw load will be about 175-225 gallon per day.



Also looked at a wastewater recovery, which seems viable.



The plumbers I've talked to so far install 3-5k mod cons with 180-200 baseboard and look at me strange when I question that.   If I start talking about in ceiling radiant, wastewater heat recovery and what not they'll probably just leave the building...



If anybody knows a smart hydronics guy in my area please do email me (joshuabisset@yahoo.com).  There's no way I'm going to design this thing myself.  I'm just trying to figure out the right direction and language to help me find the right person.

Steamhead

If all the zone piping is coming to the basement

why not put in four boilers there, and let the tenants pay for the heat?



No open windows that way, and you could secure all the equipment against tampering............................



Try the Find a Professional page of this site.

Osborn

why not..

Maybe that's the best way, we'll see. 



With the 8 machines in the basement approach, the system demands more maintenance headaches, replacements, is low efficiency .  This year my landlord has replaced two of four Bradford and White combi heaters in this building.  I'm an environmental guy so don't want one of these oversized boilers that's constantly short cycling,.  For example the tenants in the building I live in now pay more than 200 per month to heat their 700sf apts.   



Also, I wanted to find a way to integrate solar h20 and a central approach seems the only way.



But you're right about the window open thing.  That would drive me crazy...doing so much to insolate, calibrate the system ect...



Do you have any suggestions for a lower/midrange "8 machine basement solution" that could provide me decent efficiency?  The btu required will be only about 15 to 25k.



The other approach would be a tankless model in the units that would provide heat and hot water.  Here in Jersey we can't put tanks in the apartments themselves. 

Steamhead

Only 4 machines are needed

one boiler and indirect for each apartment. The indirect has no burner so its maintenance is much less.



As to brands, I like Triangle Tube indirects. For a boiler we'd need to know more about where it would go, what venting options are available etc to see what would work best. 

Bob Bona_4

if you find a way to

vent, the Laars Mascots work well for apt. jobs. Hang one on the wall in a closet in each apt, run your fin tube to it. They have built in domestic production, plenty for 1 bath.



Did a job couple years ago with 26 of them in a gut rehab.

Osborn

in unit solution

I was looking at the Navien commercial condensing .. It's about 1k less retail than the lars combi wall hung boiler.    Any feedback about that model?

Osborn

location and venting for multi tank solution

i have a narrow strip of lawn along one edge of the building.  Not sure what's code for venting.    The boilers and indirects would have to be placed in the basement.  They'd be between 15 to 50 feet from the baseboard and faucets etc.    

Bob Bona_4

naviens

are nice, but are meant to be water heaters, to put it simply. You still would need some sort of HX to seperate domestic from heating waters, then all the stuff for the hydronic side. The Mascot combi boiler (note: "boiler", not water heater) has a HX, x-tank, system circ, air elimination, fill valve, etc already inside for you. You would spend far more to make all the components up separately and externally. There is a reason why the Navien costs less, if you research.

Really, for small spaces, they just make a lot of sense to me.







 

TonyS

Bob

Navien has a new model called the combi unit. You can see it on their website. It has a flat plate exchanger in it for the domestic with a domestic override and outdoor reset on the heating side, has a real good turndown ration and is priced more like they pay in Europe...much less! I am waiting to install one. http://www.navienamerica.com/product/combi_01.aspx?skin=combi_01

Bob Bona_4

thanks

for the update, Tony, it's been about a year since the Navein rep blew thru here

Things are changing so fast!

CMadatMe

System Recommendation

I would use one mod/con with an indirect. My boiler choice would be a Viessmann Vitodens 200. I would zone each apartment alpha circ's to a manifold for supplying panel rads with trv's. I would use Vitotrols as my zone therms via KM bus. I would size my panel rads so that I was condensing all year round. Makes no sense to add any type of tankless water heater when I already have a 90percent plus mod/con. The Vitodens will also give you much better control over domestic. You could set the domestic to run for time periods. The Vitorol have built in reduced energy settings in them and will also provided indoor feedback to the boiler.



Just my idea. 

Osborn

low temp baseboard runs

Thanks all for your suggestions.  I'm looking at both the central boiler and in unit options.  The navien has some spooky reviews online??  Any other recommendations for the in unit wall hung models?  I have a heat loss of 10-25k/btu hr. 



About the hardware..

I got a quote of 14k for the panel rads and parts....  That's a bit much I think. 



I'm looking at commercial grade baseboard.  The slant fin multi pak 80 turns out 400btu/ft at 140 degrees.  Any other low temp radiator/baseboard suggestions?

CMadatMe

Panel Rads

Get a second opinion on the price of those rads. Seems rather high based on the heat losses you are talking about. Attached are some rads that you can e-mail me about. I am in your market area. Any hicap type board will work dependent on outputs at the apporiate flow rate. I think the 1 boiler approach with an indirect is your best course of action as I recommened in my above post.

Osborn

panel rad advantage

actually the quote was from those folks...maybe they did a different heat calc.  I haven't talked to them about how they came up with the #s.



What's the advantage of panel rads over running baseboard at low temp?

CMadatMe

Really?

Did you speak with Steve? Less space is the biggest advantage plus you get both the radiant and convection effect and since this is basically a new install the ability to run constant circulation.

Charlie from wmass

Reason for mutiple boilers is simple

tenant pays for fuel usage. cost is the best motivator for people to conserve. No open windows when they get the fuel bill. The maintainance needs to be factored in when determining the rent or lease agreement. What is the square footage of the units? also are they one bath or more per unit? There are small indirects that could be placed in the units. along with the boilers.

Osborn

heat in units..

i agree with you on the no more windows open point but tanks in the units is a no go here in jersey city.  they would all have to be in the basement.  that is an option...



The reason i've been trying to find a more efficient option is that the building I live in now has such a system.  lars minitherms with 40 gal tanks (used to be code).  or bradford and white water heats with a check valve.    They seem to be massively inefficient; mine is constantly cycling on and off.  People are paying more than 200 per month to heat 700sqft. 



The other reason i am looking at central -- as i mentioned above -- is that i'm interested in integrated solar into a possible radiant design.  I'd do the piping myself - which is the only way to afford that.   i'd go for a 20-30% solar radiant, i'd pay for heat and control the thermostat....

mor

Control thermostat

You might try controlling the water temp [outdoor reset], and let the tenants control the thermostats MB

NRT_Rob

dunno about NJ code

but a single heat source with BTU meters can allow tenants to pay the bill.



with water temperature control, opening windows should result in a cold room as well, even if they turn up their TRVs or thermostats. still a waste of heat, but less so.

Osborn

boiler plus btu meters

Thanks to suggestions here, I'm zeroing in on a central boiler/indirect on btu meters; lines going up to a manifold in each apt which lead to home runs to each of 4 panel rads with thermostats.    looking at Veissman (if i can find an installer) and triangle tube boilers. 



(Still not sure on the code issues in nj re btu meters but..)