Applied Air News

Over the Christmas/New Years holiday break I was able to spend some time on the road crossing Texas, New Mexico, and parts of Arizona.  While I saw plenty of interesting sights it is not the goal of this blog to create a travel channel.  The goal is to highlight technologies and subjects of interest in the HVAC arena.

The subject that came to mind as I drove across these states was that of indoor air quality.  Two areas, in particular, raised my attention to this topic.  Phoenix, Arizona and El Paso, Texas were both covered with a thick layer of smog as I passed through those towns.  The climatic reasons are not all that relevant to this discussion but the "temperature inversions" that are common in those areas at certain times of the year mean that smog will develop and stay trapped for hours, if not days.  But those two cities are not alone.  Los Angeles, California has been well known for poor air quality for years.  New York City leaders have become concerned enough about outside air quality to include provisions in their new "Green Codes" that are intended to address the issue.  Finally, attention has been brought by the folks at NOAA to the fact that pollution in China eventually makes it way to the US on the jet stream.

HVAC products can either help mitigate this problem or simply move it from the outdoors to the indoors.  All buildings with occupants are required by building codes to have some amount of "ventilation air".  It has been common practice to introduce that ventilation air through conventional air handlers or packaged rooftop equipment.  In the vast majority of cases that equipment was designed, and is applied, with only the minimum level of air filtration included.  The primary goal of the filtration has been to protect the components of the equipment from dust fouling and to provide a nominal level of indoor air quality improvement.  New requirements and guidelines that specify MERV 11 and higher filtration are intended to let the equipment begin to mitigate the outdoor air quality before it enters the space.  But how effective is this?

In a conventional HVAC system design there will be dozens of these filters, if not hundreds, scattered all over the building in numerous air handlers or packaged units.  Maintaining all of these filters properly becomes an ongoing task.  In addition, if even better filtration is required, or desired, the average piece of HVAC equipment simply lacks the space to provide more filtration.

Dedicated Outdoor Air Systems, or "DOAS", equipment helps address this.  By isolating all of the ventilation air requirements into a single point, maintenance of the filtration system becomes much easier.  In addition, some "DOAS" equipment, such as the Applied Air FAP, is designed to allow multiple stages of filtration.  When combined with low airflow systems such as chilled beams the result can be very clean ventilation air even in areas such as those I drove through over the holidays.

As a final consideration for indoor air quality I would suggest that the old, ancient actually, technology of adiabatic or evaporative cooling might be considered.  Although adiabatic or evaporative cooling can provide effective temperature control in vast parts of the United States it can also provide an extremely effective filtering system as well.  Air is literally "washed" as it passes through the unit.  As part of an overall system where the adiabatic or evaporative cooling system, such as the Alton or Aztec products, only provides the ventilation air and other equipment handles sensible and latent cooling the improvement in indoor air quality could be dramatic.

Mestex, the Dallas division of Mestek has created a YouTube channel, MestexHVAC (http://www.youtube.com/MestexHVAC?feature=guide).  Mestex will start using this format website to post informational and promotional videos.  Current videos include information about the LJ Wing MV coil, the Applied Air Dedicated Outdoor Air System, and the Adaptaire DDC control system.

Aztec Evaporative Cooling Solutions, a Mestex (Division of Mestek) company, will be exhibiting their evaporative cooling solution for data centers at the Data Center World Conference and Exhibit. Aztec will be located in booth 835. The exhibit will be March 20-21, 2012, at the Mirage Events Center in Las Vegas. Information about Data Center World can be found at www.datacenterworld.com.

This past week I was able to participate in the GreenBuild conference in Toronto.  This was my first opportunity to attend and I have come away with a few impressions.

First, I was surprised at the sheer size of the exhibit area.  The Metro Toronto exhibit hall is quite large and split into two sections spanning the CN Rail lines in downtown Toronto.  Both sections were completely full with exhibits for everything from flooring to roofing and everything in between.  All exhibitors promoted the "green" or "sustainable" aspects of their products...even if those aspects might not have been obvious on first or even second thought.  In addition to the three Mestek HVAC product booths the exhibit area included product displays from most of the major north American HVAC manufacturers. 

The HVAC equipment companies, as well as many of the lighting and appliance companies, shared one common thread.  That is the emphasis on the "man-machine interface"...how the user interacts with the equipment for control or information.  Touch screen displays were everywhere providing access to virtual control points and providing occupant feedback on temperatures and, most importantly, energy utilization.  The degree of sophistication of the displays varied but the message was the same...in order to conserve energy people must have some sense of how much they are using.  It goes back to the old saying that "you can't manage what you can't measure".  The use of energy metrics have been proven to change occupant behavior and the HVAC industry is stepping up to help with that effort.

Mestex started our efforts in that regard several years ago with our Adaptaire DDC control system and we currently provide basic control and trending information via the Internet.  More developments are underway to further enhance the user feedback and help focus their attention on conservation of our energy resources.

Mestex has been providing this open protocol system for almost 10 years and has successfully integrated with virtually every other major control protocol on the market.  This has allowed building owners to gain visibility into the various Mestex brand products through their own building automation system in order to provide a richer set of points for monitoring and control.

Anyone who follows what is going on in the cellular phone business these days knows that Apple and others launch a lawsuit almost daily against their competitors claiming infringement of intellectual property rights.  These IP lawsuits are becoming so commonplace that many "techie" websites keep running charts to show who is suing who this week.  It is said that Microsoft is making more money off licensing rights related to a lawsuit against Google than it makes off selling it's own phones.

Well, it looks like the IP lawsuit fever has spread to our industry.  The company IntusIQ has filed suit in Texas against Ingersoll-Rand, parent of Trane, and Schneider Electric, parent of APC, claiming patent infringements.  The infringements are related to the application of "mesh networks" for building control schemes.  Most of these things get settled out of court with some sort of licensing fee arrangement but with the current trend of suing over IP reaching a fever pitch in other industries this might mark the beginning of something that will impact the HVAC industry as well.

We have been promoting the Aztec evaporative cooling line to the data center market lately due to the increased interest in using outside air to cool the equipment under the new ASHRAE guidelines.  The Aztec product line also has a strong history in other applications…notably schools and prisons (interesting comparisons could be drawn there).  Over the last couple of years we have seen more and more articles describing indirect evaporative cooling systems as the solution for high LEED certifications and “green buildings” in general due to the performance and lack of any refrigerants in the system.

In order to provide better service to these markets we have improved the technical literature, brought on a temporary design specialist to document the current product design for better manufacturability, and made the unique DHTD burner technology and our DDC controls standard. 

We have now taken another step to make the product easier to apply by architects, engineers, data center designers, and advanced mechanical contractors.  The Aztec line now has Autodesk Revit BIM objects available in Autodesk SEEK for direct download into projects.  The BIM objects can also be loaded directly from within a Revit design project.

These objects join the other Dallas products that have BIM objects available.  Those include our most common direct fired heating units, our most common air turnover units with cooling, the entire Wing VIFB line, and the IFL split system DOAS unit.  As with all of our BIM objects the Aztec objects include “I” details such as cfm ranges, weight ranges, Tech Guide URL links, heating or cooling capacity ranges, cabinet materials used, and relevant agency certifications. 

The link below takes you to the Autodesk Revit site and the Aztec product listing.  The RFA files can only be opened using Autodesk Revit but the PDF product catalog can be opened and the general description info on the page can also help a designer consider the Aztec for his/her project.

http://seek.autodesk.com/search/aztec?source=SearchBox

For those who might not have seen this through their own trade associations here is an announcement of a program being planned by the US DOE. It sounds similar to programs in some European countries. There is a link to a webinar for more information about the proposed program.

The U.S. Department of Energy (the Department) is planning to develop a voluntary national Asset Rating Program for Commercial Buildings (AR Program). Through the AR Program, DOE intends to establish a building Asset Rating system that can be broadly applied to both new and existing commercial buildings, and provide affordable and reliable information to building stakeholders. The AR Program will inform building owners about the energy efficiency of their building systems, enabling comparison of the energy performance between buildings while accounting for differences in building operations and occupant behavior. The intent of the AR Program is also to help building owners identify opportunities for energy efficiency improvements.

DOE seeks the input of stakeholders and interested parties, and has issued a Request for Information (RFI) to solicit input on key issues associated with the development of an AR Program. DOE will be hosting a webinar for interested parties on August 23, 2011, at 12 p.m. (ET) to facilitate discussion on this issue. To attend the webinar, please register here to receive further information.

This particular article might get a little more technical than some previous articles but a recent visit to California prompted me to put this together. 

During a meeting with a consulting engineer I was told of a problem that he was having with a direct fired make-up air unit…not one of ours but the principles are the same.  The issue was a burner that would shut down for “unknown reasons” shortly after coming on-line.  After some discussion the engineer stated that his estimate of external static pressure was wrong because the unit was not installed as he had originally designed.  The duct system attached to the unit had several more bends in it than he designed and thus the external static pressure was higher than he estimated and higher than the manufacturer was told at the time of production.  This was the clue we needed to help the engineer understand what was going on.

Almost 10 years ago the safety standards for direct fired equipment were changed.  As a result most certified direct fired equipment provides heated air that is extremely safe from carbon monoxide, carbon dioxide, and other gaseous contaminants.  That is because the direct fired product is designed to meet a specific set of operating conditions, by code, that assure a velocity across the burner that is roughly 2,800 to 3,200 feet per minute.  When a direct fired product operates in that range then the combustion is “clean” and harmful byproducts are not produced in any significant amount.

In order to assure the user that the direct fired burner is operating in the proper range the manufacturer uses the total static pressure that is calculated for the unit (including the external static pressure) to size the airflow opening across the burner to stay within the target range.  Most manufacturers will size the opening to land in the middle of the range so that there is some room for minor errors in the estimates. 

In order to make this even more fool-proof the safety standard required manufacturers to add pressure switches to the units that would shut down the burner if the velocity across the burner was either too high or too low.  In the case that this engineer was describing the overly high external static pressure was causing the velocity across the burner to be too low and the burner would shut down.

Because the code and testing standards required manufacturers to be very specific you will find that the acceptable range between high and low is unique to each model and size in a product line.  Some of these ranges are very narrow…less than 0.25 inches of static from the high set point to the low set point.  This gives the equipment only 0.125 inches of static from the midpoint to the trip point in either direction.  Too many bends in the ductwork can easily add that much static to the system and cause the premature shutdown of the system.

Over the next weeks units shipped from Mestex Dallas will begin to include a small feature that we believe will provide large benefits to our contractor customers.

A common problem in the field with installation, operation & maintenance (IOM) documents is that they are misplaced, lost, or left in the weather and become unusable.  Over the last few years we have taken steps to make replacing those documents a bit easier by posting them on our Sales Assistant website for downloading.  While this is a big improvement over calling Dallas during business hours and ordering a document, it still requires the user to contact us and then log in to Sales Assistant for the download.

Starting July 1, equipment shipped from Dallas will continue to contain a printed copy of the IOM but it will also have a new label that includes a “Microsoft Tag” image.  Microsoft Tags are basically customized, square, barcodes that can be read by cell phones, and some tablet devices, using the free “tag reader” software from Microsoft at http://gettag.mobi.

After downloading the free reader app, if the service contractor has a cell phone with a camera he will be able to aim the camera at the tag and the software will automatically launch the phone’s web browser to open a PDF copy of the proper IOM.  IOM documents will then be available to a contractor or service technician 24 hours a day, 7 days a week.  And since the IOMs are stored in the Mestek corporate “cloud”, any updates will be automatic and it will not be necessary to keep up with revisions in the field.

Of course, once the file is opened on the phone most devices will allow the document to be saved and transferred to a computer for printing if desired.  We hope this new feature will make life a bit easier for our customers.

One of the issues that will ultimately confront designers when considering evaporative cooling solutions for data centers, or any other application for that matter, is the issue of water use. Considering that water is already an increasingly scarce resource in many areas, with projections that the situation will only get worse, it is important to consider this issue. In the data center design world the common metric of efficiency is known as the PUE but many people want to use a new metric, WUE, to reflect the water use efficiency of the data center.

Evaluating water use efficiency can be pretty tedious and is very dependent upon the location, the type of HVAC cooling system being used, and the type of electrical power plant providing the power to the building. Why do we consider the electrical power plant? Because we need to remember that electrical power plants consume vast amounts of water in the process of generating electricity and that about 70% of the power generated is lost in transmission and generation inefficiencies.

The US Geological Survey has published average water consumption rates for various types of power plants. Nuclear plants consume, on average, as much as 720 gallons per MW-h. Natural gas fired plants, commonly used for peaking plants, consume on average as much as 180 gallons per MW-h. And, coal fired plants, representing almost half of all US power plants, use on average 480 gallons per MW-h.

An additional impact of power generation is the increase in local water temperature near the cooling discharge of the typical “once-thru” plant design. (Recirculating designs are rare due to the huge increase in construction costs that they incur) This increased water temperature has ecological impacts on fish and plant life near the power plant. There is also an ecological impact near the cooling water intakes as the suction pressure of the cooling pumps is such that small fish and aquatic animals are pulled into the intake screens where they die.

So in order to accurately assess whether or not an evaporative cooling solution uses too much water it must be compared to the water use by the power plant that is providing the energy to the HVAC systems that are being compared. This becomes difficult due to the wide range of system types and locations but let’s look at a representative example using some common rules of thumb.

A typical indirect evaporative cooling unit, such as the Aztec ASC-50, will use about .25 kw/ton of energy to provide roughly 150 kw of cooling capacity. A packaged DX rooftop unit with and EER of 10.1 will use about 1.15 kw/ton to do the same amount of work. And a modern air cooled chiller will use about .88 kw/ton for the same cooling effect.

The table below shows the power required, in kw, to produce 50 tons of cooling effect from these three system types. The Aztec water consumption is a combination of the electrical power required plus the evaporation and bleed rates for the evaporative cooling process.

Using the figures from the US Geological Survey we calculated the water use for the two most common power plant types (coal is used to generate 50% of US power and natural gas is used to generate 20%). You can see that, for the most commonly used power source, the Aztec ASC indirect evaporative cooling system actually uses LESS water than the air cooled HVAC systems for the same amount of work. Of course this does not consider the environmental impact of the heated water discharge into the local reservoir from the electric power plant.

Some people would suggest that hydroelectric power is the way to counter water loss but, according to the US Geological Survey study, hydro power is actually a huge water user. The report indicates that, on average, a hydro plant will use 1,430 gallons per MW-h…roughly double that of the coal-fired plant.

Although natural gas fired power plants use less water than the Aztec evaporative cooling system there are some economic considerations. According to a 2009 study by the investment banking firm of Lazard, Ltd. a natural gas primary plant generates electricity at the rate of roughly 10.2 cents/kwh. A natural gas peaking plant generates electricity at the rate of roughly 34.2 cents/kwh. A new integrated gasification combined cycle (IGCC) coal plant generates electricity at the rate of roughly 11.0 cents/kwh. The blended electricity rate for an all natural gas utility would be significantly higher than an all coal utility. History also indicates that the cost of electricity from natural gas fired utilities fluctuates more than for coal fired utilities due to the volatility of natural gas prices.

So…do evaporative cooling systems use too much water? When you look at “source energy water use” of power plants versus the local use of an evaporative cooling unit the answer is usually “NO”. And, finally, consider that a local system offers load diversity that the power plant cannot offer, meaning that the local system can be completely shut off, using no water at all when there is no load.

I am currently at the FMA Sustainability Conference in Florida and have been listening to 2 days of presentations about ways to be a more sustainable operation.  Most of the audience would be described as executive level sustainability managers for Fortune 500 companies.  After listening to these presentations, and giving one myself, it struck me that at the Mestek facility in Dallas we are actually pretty far down the road in implementing sustainable practices.  For many, if not most, of the companies presenting or attending the conference the motivation was social responsibility with a by-product of reduced energy costs and improved financial performance.  Our motivation was financial with the by-product being sustainability...but no matter what drives you the end result is the same.  So, what has Dallas done to make us claim to be working in the direction of sustainability?

*All lighting was upgraded to high efficiency ballasts and high efficiency fixtures throughout the facility.
*Occupancy sensors are used to control lighting in areas that are not occupied at all times.
*The HVAC system is predominantly based on zero-GWP evaporative cooling.  In areas that require mechanical cooling all of the systems have been converted to R410a from *R22 for reduced GHG impact.
*Our painting process is being changed from a solvent based system to a water based system to reduce VOCs.
*We have eliminated the need for one inefficient steam boiler in our coil testing area by changing our test procedure and by changing the cutting oil used in our production process to an oil that can be cleaned with water.
*We have eliminated the need for an auxiliary cooling system in our server room by enclosing the hot server exhaust stream and venting it outside the server room.
*All scrap metals are captured and sent to a recycling facility.
*Corrugated cardboard packaging is now being compressed to reduce the impact on the landfill.
*Each office has a paper products recycle bin and the material is consolidated weekly and sent to a recycling facility.
*80% of our customer training is now conducted by web-based conferencing...eliminating thousands of miles of air travel and the associated carbon footprint.
*All product literature is available in electronic form and only printed when necessary and in the amount required.
*IOM materials can be downloaded from the Internet by scanning a barcode tag on products shipped starting in late 2011...eliminating the need for multiple copies of thick manuals.
*Invoices, acknowledgments, and engineering submittals are all generated electronically...eliminating reams of paper consumption annually.
*E-mail has replaced fax as our preferred means of sharing printed documents.

All of these steps are items that have been covered during presentations here in Florida.  In hindsight it turns out the Mestek Dallas is well along the road to sustainability...no matter the motivation.

The big announcement in the information technology and data center world today was that Facebook has decided to make their data center and custom server designs open to the public to use in their own designs. This is a huge deal in that world since most data centers have more security than Fort Knox and even their exact location is disguised. For Mestek the most interesting part of this news is that Facebook is designing their centers with NO MECHANICAL COOLING. This furthers the trend among all the big players and is driven by the enormous energy consumption of these data centers. Data centers are little more than big warehouses but can have energy loads that exceed 600 watts per square foot.

The Aztec and Alton lines of evaporative cooling products make excellent solutions for these buildings since they provide some level of cooling without the need for mechanical cooling. Data center owners get the best of both worlds...low energy use and filtered/tempered air for their servers.

This post is a little different than most of my entries but is something that anyone in the construction related industries should pay attention to. We all feel the results of the Middle East unrest when we fill up our personal vehicles but what else does this impact? The cost of everything you specify or purchase for a construction project will go up as a result of that situation on the other side of the world.

The chart says it all. Delivered prices for components used to make your equipment and delivered prices for the equipment to the job site will all go up to cover the large "fuel surcharges" that are now being added to diesel fuel. As the chart shows, the surcharge for diesel in class 371...a common class for HVAC equipment... is now 55.6%. When added to other costs for delivery the end result could be a 15% increase in total delivery costs.

Delivery costs are factored into the cost of producing products and you need to remember to include them in the costs of receiving products on your project jobsite.