021014

Submitted by brian on

COLD SPRING ELEMENTARY HEATING SYSTEM

 

Although the ROCORI District has completed the largest parts of our construction project and we have occupied all of our spaces for two school years, we have at one more major project to attack in the district.  Our current plans have the work set for the summer of 2014. 

The project involves the replacement of the heating system at the Cold Spring Elementary site. Because we are drawing closer to the time schedule and we have been in the process of securing bids for the project,  I would like to spend a little bit of time to highlight the work that will be done.

 

HISTORY

Cold Spring Elementary School opened in 1991 as a new building in the district.  The design of the building, including much of its mechanical system, was very contemporary.  The heating and ventilation system was a fairly “new” approach for schools with the core of the system built on a series of heat pumps.  The heat pumps provided for both the heating and cooling system.

Rather than one central heating or cooling plant for the building, the heat pumps provide ventilation, heating and cooling for defined areas within the building.  Essentially, there is one heat pump for each classroom area.  A larger pump system, with multiple pumps, is needed for the cafeteria, gym, commons, or other common areas like hallways. 

In order to cover the building, a total of 76 heat pumps were installed in the system at the Cold Spring Elementary site.  Each pump is an independent unit designed for its particular spaces and areas.  But, each pump is still part of the overall heating and cooling system.  If one pump goes down, it directly affects the area it “feeds” but it also affects the overall HVAC work of the building.

 

LIFE EXPECTANCY

Unlike central heating systems, the life expectancy of each heat pump is much shorter.  In our construction project, we upgraded boiler systems at several sites.  The boilers we replaced, in several cases, were more than 50 years old.  Heat pumps are not expected to last that long.

Each heat pump, from the time of installation, had a life expectancy of about 20 years.  A life expectancy, of course, is not a guarantee or necessarily an accurate reflection of when a product will cease to function, but it is a good guide.  It is an important parameter for us as to when we should be concerned about replacement of the item.

With a building that opened in 1991, a twenty year life expectancy meant that we should expect pumps to begin needing replacement at about 2011.  As one would expect, some pumps started failing before that date; some have lasted longer.  The difficulty is that we are at a critical juncture where we expect to be replacing a large number of pumps—with pumps that no longer have a twenty year life expectancy, but rather about twelve to fifteen years.

Although I don’t think I particularly “caused” it, we actually started to replace heat pumps shortly after I arrived in the district.  The reason to point that out is that many of our pumps did not last the full twenty years expected.  Additionally, some of the pumps we replaced have also already burned out.  What this means is that we have a lot of pumps to worry about replacing in the very near future.

 

OTHER ISSUES  

Beyond simply replacing the pumps, there are several other considerations.  Because we are more than twenty years from the initial heat pumps, the ones that we must use for replacement are not necessarily built the same way as the ones twenty years ago.  The pumps change shape, size, or locations for input or output.

The change of pumps means that as we replace them, we must also retrofit the areas.  Sometimes the new pump does not fit the space of the original pump.  Sometimes the capacity and size of the pump changes and that requires alterations to the system.  The bottom line is that the new, replacement pumps are not the same as the originals.

Because they are not the same, as I noted before, the new pumps do not have the same life expectancy.  We have experienced several situations where the replacement pump has already needed to be replaced.  In some cases, although it was expected to be fifteen years, the life of the new pump was only about five years—and the size and nature of that pump has already changed.

All of the changes require time, space, and funding to make the adjustments needed. 

 

QUICKLY MOUNTS UP

Depending on the size of the pump, the cost for replacement can vary.  A few years ago, with some of the smaller pumps, the estimate to replace any one pump was about $2000 to $5000.  That included our maintenance staff doing the installation—it was simply pump replacement cost. 

The cost of the pumps has been increasing pretty quickly.  The replacement of $2000 a few years ago is now about $5000.  The $5000 pump is now costing closer to $10,000.  Most of the pumps, with installation calculations, have doubled in cost.

Some of the replacement pumps, those covering bigger areas, have also increased pretty dramatically in cost and design.  One of the larger heat pumps needed to be replaced not long ago.  Because of its location and function, it was a pretty significant issue.  The new pump came in—without installation and retrofitting costs—at about $20,000.

When you begin putting the costs of the individual pumps together, the replacement becomes a pretty significant project!  Remember there are 76 pumps in the building.  In simple math, if every pump cost $10,000 for replacement, changing all the pumps would be a cost of $760,000!

Because of the rate at which the pumps are failing, we started to look at what would be required to address the entire system.  One of our consultants put together a proposal.  The pumps vary in size and scope, but the proposal to replace the entire system of pumps and controls was estimated at about $1 million.  The pumps, alone, cannot be replaced without also changing out the controls for them which brought the project to the million dollar amount.

The difficulty for us, as a district, is that we could replace every pump in one shot—at about a million dollars—and it would put us in good position for about a decade.  Remember the life expectancy of the new pumps has dropped to about 12 to 15 years and some of the replacements we have made have been closer to five years.  After about a decade, we would be faced with the proposition of replacing the pumps again.

 

DISTRICT OPTIONS

As we were looking at the options, our Facilities and Grounds Committee concluded that there must be a better option than looking at replacing all of our heat pumps in the system every decade or so—and possibly having issues regularly throughout that time.

As a district, we examined a number of options to deal with the issue of heat pump replacement.  The options included continuing with the current process of simply replacing heat pumps as they fail, looking at replacing all of the pumps at one time, or gathering information about changing our system away from heat pumps to another delivery system.

The idea of following the current path was not very appealing to the committee.  It is very unpredictable because we could go a year without any heat pumps failing or we could have numerous pumps fail.  It is unlikely that all of them would fail in a given year, but it is certainly possible that multiple pumps would fail.  That, in fact, has happened in the last few years—we have had five or more pumps fail in a single year.  Depending on the size and the capacity, the cost could range from $15,000 in a year to $100,000 in a year.

I shared last week that we had a consultant offer a proposal to replace all 76 of the heat pumps at one time.  This would bring everything current, would reduce some of the cost because all the work could be done at one time, but was projected to cost about $1 million between pumps and controls.  As we considered the option, the drawback was that it would be an effective solution for 10 to 15 years, but we would eventually be right back in the same position.

 

A BETTER PATH

The most logical approach was to consider was one that might allow us to get out of the cycle of replacing heat pumps.  Although the heat pumps make use of heated or cooled water, it was still a system that forced air through ducts into the spaces in the building.  The air ducts, while designed for the heat pump system, could be shifted into a different, forced air system.

One proposal that was offered by consultants involved replacing the entire system.  Not only would the heat pumps be removed, but the proposal included replacement of the ductwork and the entire system.  The estimate for this approach was in the neighborhood of $3.5 million.

As we considered this approach, district staff and the facilities committee  members were convinced that most, if not all, of the ductwork should be able to be salvaged through a project.  A different consultant came in and agreed with that assessment.  As they walked through the building and looked at all of the system, the conclusion was that there would be minimal need to replace the ductwork and that the core systems themselves could be changed to get the forced air system to operate.

This consultant had a much different estimate.  With most of the ductwork left alone, the change to rooftop heating and cooling systems came down to a projected cost of about $1.5 million.  To our committee and the school board—although this is still a significant amount and major project—this amount was much better and provided a much better long-term solution.

 

REQUIREMENTS

Once the idea was narrowed down, there were a number of steps to examine to determine if the project was feasible.  First, the consultant needed to develop or design the project so much more detail could be provided to appropriate authorities.

As with any significant school construction project, officials at the Minnesota Department of Education needed to be engaged.  Two particular departments at the state, the office that governs construction and the office dealing with issues of health and safety, were involved.

A new system, beyond addressing the issue of heat pumps, could also be examined in light of new air quality standards.  Although the CSE system moved air well, it did not match the levels of air movement required of new systems.  As the designers looked at the system, they knew it would need to move at least 15 cfm of air. 

With the guidance of officials at the Department of Education, the components of the project were deemed to be appropriate health and safety issues.  In this fashion, the district could move submit a proposal but have the project governed by health and safety funding because it would also improve indoor air quality for the entire site.  Although health and safety funding is a levy applied locally, it is also a funding mechanism that is at a lower overall “cost” for the district and the impact within the district would be about $15-18 per year for the average homeowner.

As the project was designed, the district also needed to submit the project under the “Review and Comment” guidelines.  This step is also required of construction projects to ensure that the project is reviewed and approved by the local school board as well as authorized by the state of Minnesota.  Our proposal was reviewed, and approved,  by the Department of Education in the Review and Comment process.

 

FINAL THOUGHTS

The proposed plan has received several points of discussion at the committee and the full board level.  The project has been under discussion and review for most of the last two calendar years—and consideration to the heat pump “problem” has been given for several years. 

The committee brought forth its recommendation for full board consideration in January of 2013.  Further plans were developed after that discussion and the issue was brought back to the full board.  In May, the board authorized the project to be submitted under Review and Comment.  The final design of the project was completed last summer. 

We have recently had meetings to include the release of bid documents, walk-throughs of the building, explain the bid process, and accept bids in the district.  The project, once the board is able to approve the bids, is set to unfold in the summer of 2014. We should be ready to proceed as school ends in 2014.