Is hotwater heating and DDC control the 'best available technology' out there?

curious_resident

I have to decide if I should vote yes or no on a bond referendum that our school district is presenting. We have 10 buildings (elementary to high) with different heating systems (forced air, hot water and steam). The systems are old and do not provide consistent heating across all classrooms and the district's architect is proposing to replace ALL heating systems with new high efficiency hot water boilers, new pipes, new unit ventilators in classrooms and new DDC control throughout the district.

We asked during a recent meeting if this can be first upgraded to 1-2 schools and tested for a couple of years, but their response was that it's well tested and a benchmark throughout schools in north east, where heat is the primary requirement. (cooling is and will continue to be done via window ACs).

Is the hot water heating best way to heat school buildings or should other options be evaluated? (some residents proposed VRV / split and that suggestion was shot down).

Thanks

hot_rod

Hydronics are commonly used for those applications, and a great way to move energy. Properly designed you can heat, cool, pre-ventilation heat air, and generate DHW with a hydronic system.

Find an engineer familiar with modern hydronic design to do a presentation.

Jamie Hall

In my humble opinion your tax dollars would be much better spent on getting the existing systems in each of the schools running the way they are supposed to run.

Maintenance is not glamorous. It doesn't make headlines or photo-ops for the engineers and architects. It's a lot cheaper than tearing out and starting over.

Any system -- steam, hot water, forced air -- can be made to work and work well and evenly. But it does take understanding of the systems, and it takes maintenance. And even the most gee-whiz new system is going to take... maintenance. And the more gee-whiz it is, the more maintenance it's going to take.

EBEBRATT-Ed

Hot water with DDC controls is your best bet. Easiest to zone and more comfortable.

nicholas bonham-carter

Is only heating needed, or is A\C needed as well?
Is the District architect an expert in heating systems?
The desire for comfortable, controllable heating systems is nothing new, and probably most of the present systems satisfied those requirements when first installed. If they are no longer functioning properly, then I would find out what has changed over the years in the various systems, and then decide how to rectify the faults.
If anyone is addicted to a new and shiny system, then just install one to replace the most damaged system. No doubt, it will be a complicated control, which is difficult to manage correctly, even if it has been installed according to the factory instructions!--NBC

Jamie Hall

EBEBRATT-Ed said:

Hot water with DDC controls is your best bet. Easiest to zone and more comfortable.

I entirely agree -- but. It might be worth finding out if the existing systems are beyond repair (probably not) before tearing them all out and starting over.

I will say again -- any system, new and shiny or old and unfashionable -- is going to need maintenance. School systems are notorious for no maintenance until something breaks.

RPK

It probably goes without saying, but the best choice really depends on the specifics of your buildings. Jamie Hall makes a good point, replacement is not always the best option. Better maintenance or selective replacement could be a better investment. If the scope of the proposed project is large enough to include replacement of entire systems in all your buildings, it may be worth considering alternatives to unit ventilators. Dedicated outdoor air units offer some distinct advantages, heat recovery being one of the biggest. I have seen VRF systems work well in a few school applications, but I think they come with some major disadvantages. A small refrigerant leak can leave a VRF system dead in the water. A small water leak can be fixed temporarily with a bucket.

The Steam Whisperer

I agree with most of the comments above. The cost of fixing the existing systems to work properly is usually a small fraction of wholesale replacement. In addition, the latest gee wiz control systems are placing the most important system in the building in the hands of the internet, quite often, and these systems get outdated very quickly. A major disadvantage of a hot water system in that environment is that a single component failure can cause a freeze up that will take the whole system down and do extensive damage. With forced air or steam, the damage is usually limited to a small area and the rest of the complex continues to be operate. That same problem applies to a DDC system. A single control failure can take the whole building down, and exposes the heating system and building to freeze ups. This is especially a problem with institutions like school districts that do not or cannot maintain ( due to tax freeze's, etc) a fancy new system to keep it reliable.
Of course there is also the basic problem of a power outage that can quickly freeze up a hot water system that is not well maintained ( ie outdoor air dampers not closing properly on failure, etc due to lack of maintenance).
Steam is an exceptional choice for institutional use for many of the reasons above.

John Mills_5

If the district is going to rip out and replace pipes, vents, controls, boilers, why not spend a bit more for a chiller and get rid of window shakers?

Brewbeer

The govt is usually required to take the lowest bidder, and as we know from the posts on here, the lowest bidder frequently doesn't know what they are doing. That's why maintenance of public buildings is so challenging for govt officials, esp. locals who frequently are p/t or volunteers in their communities.

Voyager

First question is: How old is old? I have read about steam systems that are 100 years old and still work. Not sure of any HWBB systems that old, but there may be some. FA is a more recent entrant in general, but I know of several systems that are 40 years old and still going. The last house I owned is still running on its original forced air furnace and it was built in 1961. Now, it isn’t that efficient and not that comfortable as it was poorly designed, but it was always reliable when I lived there with just a little maintenance.

I agree with Jamie in taking a really close look at your current systems before going whole hog on replacement. And with 10 buildings, I can’t possibly believe that all of them require replacement at once. I would rank them by age,efficiency, current cost of maintenance, comfort level, etc. and then develop a long-range upgrade plan. I find it hard to believe that you couldn’t get by with upgrading one school a year over the next decade. And that would give you progressive experience with whatever system type you choose so you could decide afresh each year if you wanted to stay to course or make technology or installer changes.

Steamhead

My vote would be "No".