Want to help design?

Mark A. Custis

The director of public service got the insurance company off my back until April, now I can work without an emergency button being pushed. I have a few ideas and would love to fire them with the oil fired mail box I saw yesterday, but...

I have a building with 500,000 BTUH of radiation. The existing boiler is 1,000,000 BTUH in. The loss on the building with wright soft is 289,000, with Hydronic explorer 326,000. I feel I need to be able to at least heat up the radiation, so in my minds eye the magic number becomes the same as the radiation.

The building was design built in the late 60's, before we ran out of natural gas and back in the days when more was better. I have a three pump system.

Like the old VAV stuff I have a perimiter heat loop. Then we have a Buffalo air handler (like hot deck/cold deck only using water) a 10 ton chiller and a pair of three-way valves making it all work. Barber Coleman controls by Slawson (major secretive stuff back then, like trying to look at a print of a Carrier ICB in the 70's).

WELL! I opened my mouth and before I could stick either foot into it, out blurted, "We'll pipe in a pair of 250,000 boilers. Tie 'em to an outdoor reset, self learning curve, control, use a pair of injection pumps to add the heat, then run one as #1 and then run the second as #1. We will have the redundancy of a back up boiler as the heat loss calcs say I can heat the building with just one.

I am now not in an emergency, sooooooo.

What would you guys do?

Natural gas.

I can not get a boiler or control rep. to talk to me.

Did I learn too much here?

Thanks,

Mark

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Ray M_2

Design

Are they using o.a. on the air handler and reheat on the cooling side? Do they also have a preheat circut? Also what about DHW? I ask because i would tend to design with all in mind.
Ray M

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Mark A. Custis

Ray:

Yes on the outdoor air. No on the reheat as far as I can see. I don't know yet on the pre-heat, probably not as Slawson was good, but not that good. This building went up 1969. A big thunder storm flooded the building and turned all the prints into paper mache. They got pitched. I have been fereting out piping at my exorbitant, hourly rate, and just don't know yet. No fyrerite controls, they depended on the boiler stuff to keep things safe. The chiller has been manually turned on "for years". I keep getting questions like why are you cleaning and leveling thermostats? Why are you cleaning the base board? No one has ever done that before. Why are you washing the burners?

You get the idea.

Mark

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Ray M_2

I get it

What about DHW?

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[Deleted User]

If you are

comfortable w/ the 326 mbh load, why go 500 mbh total? Why not 175-200 on each boiler w/ the primary/secondary & the reset? Should be able to scratch out several efficiency percentage points. Sure would improve the steady state.

Shame to waste all the 'puting power in those programs. Go for it.

Aidan (UK)

Big radiators

You’ve got 500,000 Btu/hr worth of radiator surface in a building with a 300,000 Btu/hr heat loss (I hope I’ve understood that bit correctly), and with an air handler also putting some heat in?

That suggests to me that the radiators are over-sized, but then they will deliver the required heat output at a reduced flow temperature. Outdoor reset control for the radiators, consider a condensing boiler as the lead boiler, you would probably be able to get the radiator return temperature below the condensing temperature for much of the heating season. Don’t supply the air handler with the reduced temperature flow going to the radiators; it will need a separate zone operating at a higher temperature,as would the DHW. New controls all round.

Why won’t the boiler or control reps talk to you?

Mark A. Custis

DWH by kenmore

Nothing now. I'll pack a spare set ot "Tees" for DWH when I pipe.

I hope I learn as fast as I talk.

Thanks,

Mark

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Mark A. Custis

Talk to me

I am older and want to be able to get 180* to the radiation at will.

Teach me,

Mark

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Mark A. Custis

Now you are talking

That is sort of what I had in mind except for the condensing boiler.

The radiation is all 180* design.

the service director whants to tell city that we will pay for the new system in ____ years. With out any insurance coverage.

you guys are great,

Mark

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kf_2

I agree with

Aidan. However, be careful and make sure that there are no reheat coils for that fresh make-up air. Make-up air can really eat up BTU's.

Approx. 75,000 BTU's for every 1,000 CFM's of outside air at a 70 degree rise.

kf

[Deleted User]

If the

B/C Valves control both the low & hi temp zones; why not aim the reset @ the high & let the valves smooth it out?

Barber Coleman has been bought at least once. But, several companies make actuators/linkages that will fit the valves. Then you can upgrade those controls too.

Have fun.

[Deleted User]

P. S.

Worked up a proposal today.

2 boilers @ 50% each vs. 1 boiler @ 100% calculated heat loss. Primary/secondary w/ HWR(Q) Staged Reset(for the 2).

Went to the the Weil Engineering Manual. Steady state for the 1 boiler figured @ 73%. The 2 boiler rig was 78%. Savings for the 2 boiler vs. 1 boiler was 6.9%.

The difference in the quotes was 10K. Customer said "very interesting." Any bets?

Aidan (UK)

BTUs & AHUs

Two zones running at different temperatures isn't a major difficulty. Some of the domestic job pictures on here have 6 or more zones.

The radiators are designed to deliver 500,000 Btu/hr at 180, on the worst case winter design day. But first, you don't 500,000 Btu/hr on the worst case winter day, and secondly, it's not the worst case day for most of the heating season. You should be able to lower the flow temperature a lot below 180 degF and still keep the building cosy, whilst having the ability to run at 180 degF if needed.


Good point about the AHU, KF. The total heat loss may be higher than 300,000. Maybe also allow heat for an anticipated replacement of the AHU, or provide tappings for additional boilers, so that you could cope with an increase in ventilation rates to bring the indoor air quality up to modern standards.

Mark A. Custis

I was a lead tech for years,

but on my own, ''they" want to sell what they have,

I am not an ME, but know what I can and will be able of doing. So, I get, "Well you only need 500K. and I've got that at XYZ warehouse in Cleveland, and an ABC control will do what you want without staging, no extrat pumps, and we can interface with the chiller loop, and talk to the three-way valves>"

So. I'm PO'ed. I'm not pleased.

Mark

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Mark A. Custis

Ron:

B/C stuff is run by Honeywell. Just an old tube type fully proporsional low voltage system. It can all go. All I will need are the conductors. I like old stuff and will keep it running if possible.

Thanks,

Mark

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Mark A. Custis

show me the numbers:

There is no new knowledge. I would love to see the numbers. We are poor in Northern Ohio and can't aford to do much, so if I have good math the sale will be made.

Thanks,

Mark

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[Deleted User]

Either there

is too much markup in what they have, or they don't want to make more $. Strange. Must be more than 1 rep. in your area. Meet them @ the job & tell them what you want to do. Put it in writing. Believe it or not, there are some reps. who want to help you succeed. And. Sometimes they learn things that will help them earn extra $.

Heck. Some have even told me about something their competition had that I was looking for. Bet your bip, I went back to them whenever I could. It is a 2 way street.
Sometimes you just have to force the issue.

Mark A. Custis

To Bed. To sleep, To dream

Thanks, just two more days, then we are history, or what ever DAN does with this stuff.

I want to know when DAN goes on the road and puts Murph in charge, who pays for the site?

To all who teach, why not.

Mark

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Aidan (UK)

On second thoughts,


The re-heat is a summer load. It would only be used when de-humidifing the supply air in summer. De-humidification is done by cooling the air below the dew-point, typically to 11 degC, causing the excess moisture to condense out, and then re-heating the air back to the minimum supply temperature, typically around 17 degC.

The boilers would be sized on the peak winter load; the summer re-heat shouldn’t require any increase in the boiler capacity. The frost pre-heater and the heating coil should be a component of the winter load. It’s usual to use the same coil for re-heat and winter heating, but only the winter heating demand would be added to the peak load on which you'd select the boilers. You’d still need to investigate the AHU heating demand to ensure the pipes and pumps are up to the job.