Monday, July 20, 2009

Greening Small Rooftop Package Units: Foam Core Panels in Depth

A while back, I summarized the benefits of foam core panels in comparison to the industry standard of fiberglass batt insulation.



Now Aaon has published an in-depth, seventeen page study of the benefits of the foam core panel.


Foam core panels have many advantages over standard insulation:
  • Superior R-value
  • No thermal breaks
  • Greater Rigidity
  • Lower leakage
  • Stronger damage resistance

This new study calculates the effect of these advantages over the course of a year, in heating and cooling, for buildings in Atlanta, Chicago, Houston, Los Angeles, Miami, Minneapolis, New York, Seattle and Tulsa.

This study quantifies the benefit of this advanced cabinet construction to assist engineers and owners asses the benefit of demanding higher performance out of their roof top systems.

Tuesday, March 31, 2009

White Rust: What it is, and How to Protect Your Project



What is "white rust"? Well, while it is white, it really isn't 'rust' in the normal sense of iron-oxidization. White rust is instead a corrosion product of zinc oxidization that often strikes galvanized surfaces subjected to moisture. In our industry, the most common victims of this corrosion mechanism are cooling towers and fluid coolers. And in these products, white rust can cause thousands of dollars of damage in a relatively short period of time.

White rust damages equipment by allowing a rapid and localized corrosion of the protective zinc coating on galvanized surfaces. Normally, in a galvanized surface, the zinc protects the underlying steel by providing a sacrificial cathodic protection to small areas of exposed steel, and provides bulk protection by providing a durable protective inert zinc oxide coating to prevent exposure of the underlying steel.

In white rust, however, this normal oxidation of the zinc surface goes wrong, and instead of providing a durable dull-gray surface, a porous, powdery or waxy oxide is produced instead. This corrosion product allows a rapid removal of the protective zinc surface--made worse in that the corrosion is generally localized in 'cells' which cause a very quick penetration of the zinc surface, exposing the underlying steel in a pitting process.

In recent years, the incidence of white rust has increased dramatically, leading the industry to study the process in greater depth. The Association of Water Technologies has produced an informative paper (pdf) that investigates the reasons for this increase (essentially changes in the methods used to produce galvanized sheet metal and water treatment methods) and how to prevent its occurrence.

Generally, white rust is more prevalent in soft water areas, which makes it a big problem in the Pacific Northwest. Preventing it entails both design and operational considerations.


White Rust Cells in Basin of Tower

If galvanized surfaces are used in your tower, it is critical that the tower be subjected to a 'passivation' treatment. This is a temporary water treatment regimen in the first few weeks of tower operation that acts to ensure the development of a desirable zinc oxide surface. Evapco discusses this process in this engineering bulletin. If Evapco's non-chemical Pulse~Pure product is provided, passivation is be included in the first year service that is provided with all installations. It is critical that this be performed immediately upon filling the tower with water--if water is left in the tower untreated for a period of time before the passivation treatment begins, white rust cells can develop in the interim. This is a very common cause of white rust corrosion in otherwise well-treated towers.

The other method to avoid problems with white rust in your tower installations is simply to chose your materials of construction wisely. In cooling towers, the most critical portion of the system is the basin--white rust can cause a rapid pinhole leak through the basin of a galvanized basin that would require immediate refurbishment. Providing a 304 ss basin is a very economical way to avoid costly system renovation at a future date. For areas with high chlorides, or when using water treatment methods that operate at high cycles of concentration (thus increasing the low chloride content of the utility water to dangerous levels) 316 ss is also available. Of course, the entire tower can also be constructed from these corrosion-resistant materials if desired.

In fluid coolers, however, the coil is an additional problem area. White rust on this galvanized component can rapidly lead to perforation of the closed-loop side of the system causing loss of cooling water and/or glycol coolant into the open loop side of the system. This can be a triple-threat due to the economic loss of glycol and water, an increased threat of freeze up, and huge water-quality problems due to bacterial growth and plasticization due to glycol exposure in the open side of the cooler.


Plasticized Bacteria/Glycol Slime: Yuck


The coil in your fluid cooler is the single most expensive component in it, by a large margin. And replacing coils can be an extremely costly proposition, especially in coolers without easy access to the coil section.

Until recently, there hasn't been a lot of choice for protection of this critical component of the system. Other than selecting a tower, like Evapco's highly efficient ESWA fluid cooler, that provides easy coil access for coil replacement, the usual option was to ensure a thorough passivation program. However, Evapco has now introduced 304 SS fluid cooler coils to protect your project's investment in this costly and critical component.



White rust is a problem that can cause great economic losses for building owners and operators. Thus it is critical that designers and contractors are aware of the prudent requirements necessary to prevent this damage. But with simple precautions, namely requiring a passivation program or wisely selecting materials of construction, this problem can be avoided in your projects.

::::::::::::::

But what if it's too late, and you already have white rust on your tower? Well, there are an array of options, including attempting to re-passivate the galvanized surfaces or a full refurbishment of the basin using a polymer coating like Evapco's Evapliner. The helpful people at Fluid-Tek would be happy to help you determine the best course of action for your project.

Sunday, March 1, 2009

Fan Matrix White Paper

In a previous post I discussed the advantages of the Climate Craft Matrix fan array system.

Climate Craft has now published a white paper that explores these advantages in more depth.



This paper discusses applications and advantages of this system, including:
  • VFD Considerations and Electrical Requirements
  • Sound and Efficiency Considerations
  • Vibration
  • Space Considerations
  • Reliability
  • Serviceability
  • Fan Isolation (Backdraft Dampers)
  • Cost
  • Common Options
This white paper is well worth review and will help designers and owners evaluate the best applications and advantages of this fan innovation.

LEED™ and Pulsed-Power Water Treatment


Pulsed-power water treatment offers many advantages to designers of sustainable systems.

First, it eliminates the use of industrially produced chemicals and their subsequent release into the environment. Secondly, it provides superior control of scale and biological growth, both of which negatively affect the efficiency of systems utilizing treated condenser water. Pulsed-power water treatment also allows safe operation at high cycles of concentration in the condenser water which acts to reduce the use of our limited water resources.

But there are other ways in which Pulsed-power water treatment can contribute to the sustainability of your project--and these can often lead to opportunities to gain LEED™ points.

Evapco
has developed their Pulse~Pure pulsed-power water treatment system in an effort to minimize the impact of our engineered systems on the environment. They have also provided a handy guide to attaining credit for this reduced impact through attaining points through the LEED™ program:



If you are considering a sustainable project where condenser water systems are to be used, it is well worth the effort to see if pulsed-power water treatment fits into your goals.

Monday, February 23, 2009

Johnson-Barrow/Fluid-Tek support Leukemia Research


Johnson-Barrow/Fluid-Tek are participating in this year's "Big Climb Seattle" on March 22nd, 2009.

This is a stair walk (or run) up 69 flights of stairs in the Columbia Center building. That's 1,311 steps total, with an elevation gain of 788 feet!

Our "Go Green" team is currently soliciting donations to meet our team goal. If you think this is a worthy cause, please click on the link above and click on the team member whose totals you wish to add to.

If you use this website and find it has useful information, I would consider a donation in the name of Rand Conger to be a fitting thank-you. If you think the whole idea is a good one, I might suggest donating in Angela Lambert's name, since she was the one who coerced all of us into this....

Please consider donating to this cause. Help the "Go Green" team reach their 'lofty' goals!

(Or, even better, JOIN team "Go Green"!)


That's a long way up (gulp!)

Thursday, January 15, 2009

Ultra-Low Sound Air-Cooled Chillers


Air-cooled chillers provide significant advantages for many facility operators and owners. The elimination of a cooling tower greatly reduces the complexity of the system and significantly eases the maintenance of the system. For smaller facilities without the resources of large institutional owners, this reduced maintenance can be critical.

Therefore it is very common to see air-cooled chillers on smaller facilities such as public schools and small office buildings. However, this suitability does carry with it some costs--Air-cooled chillers are usually significantly less efficient than water-cooled chillers and, now with the advent of super-low sound cooling towers, often much noisier. The noise problem can be very significant with this sort of equipment in that a large proportion of the facilities that utilize this technology are located near or in residential areas.

In an earlier post I discussed how the Smardt air-cooled Turbocor chillers significantly change the balance between water-cooled and air-cooled chillers with respect to efficiency and sound. However, it is worth investigating the sound issue in more depth.

Recently, manufacturers have spent some effort in addressing the sound issue on their air-cooled chillers. This has generally been approached by providing low sound fans and addressing the compressor noise. Two products that are currently being marketed as low-sound chillers approach compressor sound in different ways. One product utilizes screw compressors with a VSD to reduce compressor sound at low loads. Another utilizes scroll compressors with elaborate compressor sound enclosures. This approach yields published sound data which is excellent at all chiller load conditions. Until recently, this chiller has been considered by many engineers to be the quietest air-cooled chiller n the market.

The Smardt chiller, of course, uses the extremely low-sound Turbocor compressor, and variable-speed ultra-low sound fans. It is reasonable to believe that this combination would make for a very favorable comparisons with these other low-sound chiller options.

And this expectation is borne out by the data. Smardt air-cooled chillers compare extremely favorably against the variable speed screw chillers as this graph illustrates:


Two things should be noted: First, the comparison here is between a 177 ton screw and a 200 ton Smardt chiller, and second that even at 100% load, the Smardt chiller is far quieter than the screw at 25% load. The difference is even more significant in the lower octave bands that carry so well over distance.

Comparing the Smardt Chiller to the acoustically treated scroll chiller also yields an extremely favorable comparison:



This comparison of 120 ton chillers shows that while both approaches yield extremely low sound levels overall, the Smardt chiller beats the competitor in 5 of 8 octave bands. And the advantage for the competitor in two of the other bands is slight. It also shows the significant effect of A-weighting sound data. In this graph, the red line represents the published sound data from the manufacturer. Close reading of this data indicates that it is not bare sound power, but A-weighted sound power. This method of reporting sound data takes very significant credits into effect, especially in the lower octave bands:

Octave band center frequency (hz) Weighting
31.5 -39
63 -26
125 -16
250 -9
500 -3
1k 0
2k 1
4k 1
8k -1


The dark blue data show the raw, uncorrected sound data for this chiller.

If acoustics are a design consideration for your air-cooled chiller product, Smardt offers a solution that is unmatched in the industry.

Extra: Audio Comparison of compressor noise

85 dBA screw compressor
73 dBA Turbocor compressor

Both measured at 1.0 m away from compressor. Your speaker volume will affect the output, but the comparison should be clear if the volume is not adjusted between clips.

Extra extra:

This link has sound files that illustrate the amplitude of a decibel, to give perspective to the graphs above.

Tuesday, January 13, 2009

EPA proposes tighter R-22 Refrigerant Regulations


In a move that could significantly affect the application of R-22 in the HVAC marketplace, the Environmental Protection Agency has proposed new rules on the Phase-out of R-22. These rules affect both the allocation of R-22 production and the installation of these products. According to an article in ACHR News:

The proposed “Adjustments to the Allowance System for Controlling HCFC Production, Import, and Export” appears to allow to EPA to go beyond the 75 percent target effective Jan. 1, 2010. The ruling also provides production allocations for various refrigerant manufacturers, ending some uncertainty in that matter.

The proposed “Ban on Sale or Distribution of Pre-Charged Appliances” says that as of Jan. 1, 2010 it will be illegal to import, produce, or sell R-22 for use in new equipment or pre-charged into such equipment. In effect, the ruling appears to say that if a contractor buys a product as of Jan. 1, 2010 that needs R-22, the charging would have to be done with existing recovered, recycled, and/or reclaimed R-22 — or R-22 alternatives — rather than virgin R-22.


These changes are significant and are detailed in depth in the AHRI summary comments of these changes.

There as a public comment period for each of these rules. EPA will accept comments until February 6, 2009 for the pre-charged rule and March 9, 2009 for the allocation rule.

Cautious owners and engineers would be wise to strongly consider making a complete switch to the HFC alternates readily available today, R-410a being the most likely option.

Monday, January 12, 2009

Tax Breaks for Ground Loop Systems

With the signing of The Emergency Economic Stabilization Act of 2008, H.R. 1424, the Federal Government has put their money where their mouth is and have acted to make geothermal heat pump systems a more attractive HVAC alternative.



Commercial geothermal heat pump installations now qualify for a 10% tax credit, with no cap on the credited expenditures!

For commercial installations, an ITC is provided for geothermal heat pumps equal to 10 percent of the expenditures, including allocable labor costs for facilities placed in service after October 3, 2008. There is no cap on the amount of expenditures which can be used for the credit (and no cap on the credit itself). In addition, geothermal heat pumps are eligible for Modified Accelerated Cost-Recovery which provides for depreciation over 5 years. The credit is determined by the cost of the system. However, if the equipment is financed by any subsidy program (federal, state or local) or with tax-exempt bond, the basis of the equipment must be reduced by the amount of the subsidy. Contrary to the residential credit, on commercial applications the units do not need to be Energy Star rated to apply. To collect this credit, the taxpayer would need to complete IRS Form 3468. The form will need revision by the IRS to reflect the addition of geothermal heat pumps.


Every little bit helps to get these highly-efficient systems to pencil out. Uncle Sam has lent a hand to owners and designers who wish to utilize this exciting technology!