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  • Dawn of Solar Data Centers?


    Major player projects can point to readiness, costs and benefits of solar power for data centers.


    Water, water everywhere,

    And all the boards did shrink.

    Water, water everywhere,

    Nor any drop to drink.                The Rime of the Ancient Mariner - Samuel Taylor Coleridge


    Data center managers must feel a lot like Coleridge’s Ancient Mariner when they look out the window (assuming their offices have any windows). Like the sailors on Coleridge’s journey, data center professionals are surrounded by free power from the wind, sun, water,the earth’s heat and biofuel, but none of it is usable as it exists to power the insatiable demands of the equipment inside the vessel. Despite this challenge, there have been several interesting projects regarding green energy sources. This piece in the data center energy series will explore solar photovoltaic to help determine if the technology is suitable to provide cost effective, reliable power to data centers.


    Temperature@lert Blog: Dawn of Solar Data Centers?
    Left: Engraving by Gustave Doré for an 1876 edition of the poem. "The Albatross," depicts 17 sailors on the deck of a wooden ship facing an albatross. Right: A statue of the Ancient Mariner, with the albatross around his neck, at Watchet, Somerset in south west England where the poem was written. (Link to Source - Wikipedia)


    Solar powered data centers have been in the news recently primarily due to projects by Apple and Google. In an effort to build green data center, Apple’s Maiden, North Carolina 500,000 sq.ft. site is powered in part by a nearby 20-acre, 20-megawatt (MW) solar array, The site also has a 10-MW fuel cell array that uses “directed biogas” credits as the energy source. (Link to Apple Source) The remainder of the power needed for the site is purchased from the local utility with Apple buying renewable energy credits to offset the largely coal and nuclear generated Duke Energy electricity. Apple sells the power from the fuel cells to the local utility in the form of Renewable Energy Credits used to pay electric utility bills. Apple expects that the combination of solar photovoltaic panels and biogas fuel cells will allow the Maiden data center to use 100% renewable energy or energy credits by the end of the year. Several lesser known companies have also implemented solar initiatives but the news is not so widespread.


    Temperature@lert Blog: Dawn of Solar Data Centers?
    Left: Apple Maiden, NC data center site shows solar array in green (Link to Source - Apple); Right: Aerial photo of site with solar array in foreground (Link to Source - Apple Insider)


    It will be instructive to follow reports from Apple to determine the cost-effectiveness of the company’s green approach. That being said, many if not most companies do not have the luxury of being able to build a 20-acre solar farm next to the data center. And most have neither the cash to invest in such projects nor the corporate caché of Apple to get such projects approved, so initiatives such as Maiden may be few and far between. Still, there’s a lot of desert land ripe for solar farms in the US Southwest. Telecommunication infrastructure may be one limitation, but California buys a lot of its electrical power from neighboring states so anything is possible.

    What about solar power for sites where the data center is built in more developed areas, is there any hope? Colocation provider Lifeline Data Centers announced their existing 60,000 sq. ft. Indianapolis, Indiana site will be “largely powered by solar energy”. (Link to Source - Data Center Dynamics) Author Mark Monroe’s piece titled Solar Data Center NOT “Largely Solar Powered” thought about his solar panel installation and took a at the numbers behind this claim. Lifeline is planning to install a 4-MW utility-grade solar array on the roof and in campus parking lot by mid-2014. Author Monroe takes a swag at determining how much of the data center’s power needs will be filled by the solar array.

    Assuming the site’s PUE is equal to the Uptime Institute’s average of 1.64 and taking into account the photovoltaic array’s operating characteristics (tilt angle, non-tracking), site factors (sun angle, cloud cover), etc., Monroe calculates that 4.7% of the site’s total energy and 12% of the overhead energy will be available from the solar installation. At an industry leading PUE of 1.1, the installation will provide 7% of the total energy and 77% of the overhead energy. Monroe notes that while these numbers are a step in the right direction, Lighthouse’s claim of a data center “largely powered by solar energy” is largely not based on the facts. His piece notes that even Apple’s Maiden site with 20 acres of panels only generates about 60% of the total energy needed by the site overhead and IT gear. Lifeline would need to add and extra 6-MW of solar capacity and operate at a PUE of 1.2 to operate at Net Zero Overhead.

    I am curious to see hard data from these and other solar photovoltaic projects for data centers that will show hard cost, performance data and financial incentives (tax considerations, power contracts, etc.) that the industry can review to determine if solar is the right approach for their electrical power needs. Although such disclosure is unlikely due to competitive considerations, it would greatly assist the industry to help promote such green initiatives to help take the spotlight off of headlines criticizing the “power hungry monster”.

    All efforts to improve industry efficiency and reduce energy consumption are steps in the right direction. Companies like Lighthouse Data Centers that don’t have the deep pockets of Apple or Google are taking steps toward the goal of Net Zero Overhead. The challenge for data center operators that initiate green energy or efficiency based projects will be to boast about these efforts to make headline grabbing claims that may not be well supported by the data. As Launcelot Gobbo tells Old Gobbo in Shakespeare’s The Merchant of Venice, “but at any length truth will out.” Green powered and energy independent are claims that need to be examined carefully to maintain industry credibility and good will or “truth will out.”

    Temperature@lert FREE IT Monitoring Guide

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  • Does Cogeneration Yield a Suitable RoI in Data Centers?


    What does the data say?

    This is the second of two pieces on Cogeneration or CHP.  The first explored the topic, this one will explore the RoI of technology proven for other industries as applied to data centers.

    As the data center industry continued to consolidate and competitiveness becomes more intense, IT professionals understand the pressure on both capital and operating budgets.  They are torn by two competing forces, faster and more reliable vs. low cost and now.  IT equipment improvements are continuously and the desire to update always calls.  Reliability has become the mantra of hosted application and cloud customers and although electrical grid failures are not considered “failures against uptime guarantees” for some, businesses affected by outages feel the pain all the same.  And if there are solutions, management pressure to implement them quickly and at low cost is always a factor.

    Cogeneration is typically neither fast nor cheap, but it does offer an alternate path to reliability and uptime.   As in all major investments that require sizable capital and space, the best time to consider cogeneration is during data center construction.  That being said, data centers operating today are not going any place soon, so retrofit upgrade paths are also a consideration, especially in areas where electric power reliability from the local utility has become less reliable over time.  So when should data center professionals consider cogeneration or CHP?  Fortunately there are studies available on public websites that help provide answers.

    Temperature@lert: Does Cogeneration Yield a Suitable RoI in Data Centers?

    University of Syracuse data center exterior; Microturbines in utility area (Link to Source)

    One such study is an installation at the University of Syracuse.  Opened in 2009, the 12,000 ft2 (1100 m2) data center with a peak load of 780 KW employs cogeneration and other green technologies to squeeze every ounce of energy out of the system. (Link to Source)  The site’s 12 natural gas fueled microturbines generate electricity.  The microturbine’s hot exhaust is piped to the chiller room, where it is used to generate cooling for the servers and both heat and cooling for an adjacent office building.  Technologies such as adsorption chillers to turn heat into cooling, reusing waste heat in nearby buildings and rear door server rack cooling that eliminates the need for server fans completes what IBM calls its Greenest Data Center yet.

    Temperature@lert: Does Cogeneration Yield a Suitable RoI in Data Centers?

    Left: Heat exchanger used in winter months to capture waste microturbine heat for use in nearby buildings; Right: IBM “Cool Blue” server rack heat exchangers employ chilled water piped under floor.

    This is certainly an aggressive project, but can the cost be justified with a reasonable Return on Investment?  Fortunately data has recently been released to quantify the energy conservation benefits.  PUE performance measured during 2012 was presented at an October 2013 conference and show a steady PUE between 1.25 and 1.30 during the period, a value that compares very favorably when compared to the typical data center PUE of 2.0. Uptime Institute self reporting average PUE is 1.65 with qualifications, Digital Realty Trust survey of 300 IT professionals with annual revenues of at least $1 Billion and 5,000 employees revealed PUE of 2.9.  (Link to Sources: Uptime Institute Digital Realty Trust)

    Temperature@lert: Does Cogeneration Yield a Suitable RoI in Data Centers?      

    IBM/SU Green Data Center 2009 Goals (Link to Source); 2012 Actual Performance (Link to Source)

    So how can we calculate the actual RoI and compare it to the projected goals.  First, the goals stated in the table on the left show savings of $500,000+ per year.  Another presentation by the microturbine supplier shows a $300,000 per year goal, quite a bit different.  So how do we know what the savings is?  We don’t since there is no reference site where the data center is identical and in an identical location without the CHP.  So we can use the 2.0 average PUE and calculate the energy savings, but that’s not a real answer.  And we also need to take into account the fact that tax incentives and grants such as the $5 Million for the Syracuse University project needs to be reviewed to determine the cost to non-subsidized projects.  Hopefully project managers will provide more information to help data center operators better understand the actual savings as the project matures.

    CHP for data centers is presented with an array of benefits including improved reliability through less dependence on grid power, lower power costs, reduced carbon footprint.  NetApps installed CHP in their Silicon Valley data center to reduce their reliance on grid power due to frequent rolling brownouts and the uncertainties of the power market costs.  Their experience is not as instructive due to the site’s reduced need for cooling due to use of direct air cooling.  As a result the CHP system is used only when the utility is strained.  It is difficult to find quantitative data for modern installations.   While the data seems encouraging, actual energy cost savings are not provided.  We will watch the progress at this and other projects over the next several months to see if CHP costs yield an acceptable RoI via reduced energy costs.  Stay tuned.

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  • What Not To Do in a Server Room: 3 Server Room Commandments

    There's advice everywhere, whether on ServerFault or TechRepublic or any other web source you may have googled for, there is someone always giving you a 1001 tips on how to do your job best. Often these "How-To" tips are formulated for those with big budgets to spend from equipment to monthly recurring costs. However, not everyone can adhere to these perfect guidelines when there are budgetary constraints. The dilemma on how best to serve your server room with such constraints comes down to 3 simple commandments:

    (1) Thou Shalt Not Build Before Assessment of Space

    The best place to start is to assess the overall space. There's no better way than that to decide how to fit cables, wires, racks, cabinets, patch panels, cooling units, and any other mission critical equipment. By observing the overall layout, you will want to look for where walls, windows, and doors are located as well as air ducts. Then decide how to best use the space, you can get better energy efficiency as well as less hot aisles! Also don't forget to keep your wires neat and color coded for the future!

    (2) Thou Shalt Not Stack Upon Stack

    Your equipment is expensive, not flapjacks, let's not stack them. Sure this faux-pas has been done often using server rails. Yes, they are often necessary when your space is the size of a child's closet; however, the answer is not to stack them directly on top of each other. Your equipment is holding precious data or running mission critical events, the last thing you want to do is to overheat your equipment and cause failure.

    This offense is not only seen using server rails but all over the place in a server room. It's definitely a no-no to leave small pieces of equipment on top of a hot rack or cabinet. There's a reason we give them aisle spacing, it's important not to stack upon your rack, especially when there is not enough air circulation going on. Beware of dust collecting as well, the last thing you want is a dust bunny getting caught in the exahust of your server.



    (3) Thou Shalt Not Skimp on the Cooling

    As cool as raised flooring maybe, not everyone can afford it and not just any builder can do it. However, there is a variety of air conditioners available on the market that are cost-effective and energy efficent as well! Since ASHRAE raised the limits on running server equipment from 68°F to 85°F before things really start to go bad in your server room, it is possible to run your equipment at higher temperatures. By doing so and not skimping on cooling, one can run at high prpoductivity without fear of losing data as long as their air conditioning is running.

    But what happens when the air conditioner goes out? That's when things start to go bad especially when your equipment is running at higher productivity thus producting more heat. Without cooling, mission critical equipment failure could occur, or even worse, server room fire. Although they are rare, make sure you have a fire supression system; But I would not not immediately opt for the water sprinkler system since your server room equipment was not made for such aqueous activities.

    The most cost effective and best protection you can provide for your server room on a budget is to monitor for temperature. That way you can be alerted to changes in raising temperature before it's too late. After all it's better to be safe than sorry.


    Is your server room or do you know of someone's server room that is not being monitored for temperature? Are you concerned with energy consumption, ability to monitor off-hours, and/or preventing mission critical equipment from failure? If you or know someone who is experiencing such issues, we want to hear form YOU!


    We will be giving away ONE FREE USB DEVICE per month to the server room with the most need! Valued at $129.99,Temperature@lert USB Edition is a low-cost, high-performance device that monitors the ambient temperature in your server room and alerts you via email when the temperature rises or falls outside your acceptable range.

    Enter here or please send a brief description, pictures, and/or videos to diane@temperaturealert.com for consideration! Our team will select one winner each month based on description and need, because we firmly believe that companies in every industry should take a proactive stance in monitoring temperatures to avert disasters.


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  • TEMPERATURE@LERT RECOGNIZED BY COMPUTERWORLD AS A 2013 COMPUTERWORLD HONORS LAUREATE

    BOSTON, MA—March 19, 2013— IDG’s Computerworld Honors Program today announces Temperature@lert as a 2013 Laureate. The annual award program honors visionary applications of information technology and promoters of positive social, economic and educational change.

    “Technology continues to play a pivotal role in transforming how business and society functions. For the past 25 years the Computerworld Honors Program has had the privilege of celebrating innovative IT achievements,” said John Amato, vice president & publisher, Computerworld. “Computerworld is honored to recognize the outstanding accomplishments of the 2013 class of Laureates and to share their work. These projects demonstrate how IT can advance organizations' ability to compete, innovate, communicate and prosper.”

     

    Approximately 100% farmers over-water their crops and plants.  The vast majority (90%) of water use by farmers in the United States is for irrigation. This causes significant water waste, runoff, and wasted dollars. The agricultural industry is a major player for ground and surface water usage, which accounts for about 80% of the water consumption in the United States. Therefore, a solar cellular environmental monitoring device saves water and therefore, also saves fuel and dollars while promoting crop growth.

     

    By discovering the correct amount of water to use, a farmer can cut costs, spending, and reduce their strain on the water system. Their unit can save enough water in a year for up to 9,000 people. This assumes a 200-acre farm, 6.21 gal water/cu ft on farm per year, 50% water reduction, and 50 gallons per day of water use per person.


    Harry Schechter, President and CEO of Temperature@lert. “Historically, our Cellular Edition has found its way into the agricultural markets through our traditional channels. After all who wouldn’t want to help save water and promote food growth? These are very important matters in sustainability and we’re glad to be a part of the solution, and we’re ecstatic for the opportunity to help save our country’s valuable fresh water resources as well as promote crop growth as a Computerworld Honors Laureate.”

     

    The Computerworld Honors Program awards will be presented at the Gala Evening and Awards Ceremony on June 3, 2013 at the Andrew W. Mellon Auditorium in Washington, D.C.

     

    About The Computerworld Honors Program

    Founded by International Data Group (IDG) in 1988, The Computerworld Honors Program is governed by the not-for-profit Computerworld Information Technology Awards Foundation. Computerworld Honors is the longest running global program to honor individuals and organizations that use information technology to promote positive social, economic and educational change. Additional information about the program and a Global Archive of past-Laureate case studies, as well as oral histories of Leadership Award recipients can be found at the Computerworld Honors website.

     

    About Temperature@lert

    Temperature@lert’s temperature and environmental monitoring solutions provide both real-time and historic views of a location’s temperature and other critical parameters through alerts and cloud-based graphs, data logs, and reports. This information allows customers to immediately react to potentially disastrous temperature fluctuations or other changes in critical environments, as well as provide temperature consistency for regulatory and internal process control requirements. Temperature@lert has more than 40,000 devices installed in over 50 countries around the globe. For more information, please visit http://www.temperaturealert.com.

     

    About Computerworld

    Computerworld is the leading source of technology news and information for IT influencers, providing peer perspective, IT leadership and business results. Computerworld’s award-winning website (http://www.computerworld.com/), bi-weekly publication, focused conference series, custom solutions and custom research forms the hub of the world’s largest (40+ edition) global IT media network and provides opportunities for IT solutions providers to engage this audience. Computerworld leads the industry with an online audience of over 3.5 million unique, monthly visitors (Omniture, August 2012) and was recognized as the Best Website by ASBPE and TABPI in 2012. Computerworld is published by IDG Enterprise, a subsidiary of International Data Group (IDG), the world’s leading media, events and research company. Company information is available at http://www.idgenterprise.com/.

     

    Note: All product and company names are trademarks of their respective companies.


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  • Temperature@lert Named a 2013 Winner of Boston Business Journal's Best Green Practices Award for Invention

    Temperature@lert has been selected as a winner of the Boston Business Journal’s “Best Green Practices Awards” for invention. The Boston Business Journal honors many companies for accomplishments in design, innovation, invention, and for other notable strides in green practices.  Temperature@lert will be honored for their accomplishment for invention at a breakfast at The Seaport Hotel on Friday, April 12, 2013.

    Temperature@lert’s TM-CELL540-S solar powered, cellular sensing and alerting system combines Temperature@lert’s latest generation cellular engine with a host of agricultural related sensors and control devices.  By using Temperature@lert’s industrial smart sensors, agriculturalists now have the ability to use technology to effectively monitor and ensure proper crop growth, as well as save water. For example, if an action is taken, such as turning on sprinklers to prevent frost from damaging crops, customers will receive emails, SMS text messages, and phone calls to inform them of the status change.

    Close to 100% of farmers in the United States over-water their crops and plants.  The vast majority (90%) primarily use water for irrigation purposes. These two percentages paint a grim picture of water waste, runoff, and wasted dollars for the agricultural community. The agricultural industry is a major player for ground and surface water usage, accounting for about 80% of the water consumption in the United States.

    Their solar cellular environmental monitoring device saves water, and as a byproduct, also saves fuel and maintenance dollars. By discovering the correct amount of water to use, a farmer cannot only cut costs and spending but he/she can prevent over-watering and reduce their individual strain on the water system. The Solar Cellular Unit can save enough water in a year for up to 9,000 people. This assumes a 200-acre farm, 6.21 gal water/cu ft on farm per year, 50% water reduction, and 50 gallons per day of water use per person.

    Publisher of the Boston Business Journal, Chris McIntosh, said it best, “Our Best Green Practices event is a celebration of the environmentally aware and intelligent approaches that increasingly define Boston business.” With such an innovative group of green practices winners for 2013, Temperature@lert looks forward to meeting the other winners and sharing a deeper insight into green practices performed and showcased in Boston.

    “Temperature@lert is greatly honored to be recognized for its Solar Cellular Edition in green practices by the Boston Business Journal. We are ecstatic to be working within the agricultural industry, where we get to help growers with their crops while saving water one of our nation’s valuable resources,” said Temperature@lert’s President and CEO, Harry Schechter. “Who wouldn’t want to help save water and promote food growth? These are very important matters in sustainability and we’re glad to be a part of the solution.”

    For more information on Temperature@lert’s Solar Cellular Edition, please visit http://www.temperaturealert.com/Wireless-Temperature-Store/Temperature-Alert-Solar-Cellular-Sensor.aspx.


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  • Essential Tech Check List: Building & Retrofitting Your Server Room

    Whether you're building a server room, adding on, or moving equipment there are many considerations to mull over. From the basics to alarm systems, it is important to ensure your server room is efficient and to protect your mission critical equipment. Previously in our blog, we have addressed the issues surrounding the microclimate present in your server room; however, it is critical to have an understanding of how a server room should be laid-out and managed. Use our check list as a guide for promoting security, efficiency, and productivity:

    Our Essential Tech Check List

    (1) Your Basics of Space

    • -Examine the layout of the space and how many units of space you have to work with.

    • -The walls (including ceiling) and doors should isolate the sounds that your equipment is creating.

    • -Check to see which way the door opens. There should also be no windows or other entry points other than the doors in the room.

    • -Consider the floor and whether your equipment will need raised flooring. Aim for anti-static floor finishing to prevent an unwanted static charge.

    • -Make sure there is enough clearance for racks and that they are stable enough to hold your equipment.

    • -Check for aisle clearance too, make sure your have enough room for exhaust to escape and not over-heat nearby equipment.

    • -Think about whether you need ladder racks, cabinets, shelves, patch panels, or rack mounts.

    • -Take into weight and size of each piece of equipment into consideration when designing the layout.


    (2) Keeping Your Cool

    • -Check and see what type if centralized cooling is available, whether an under the floor air distribution or an air duct system.

    • -If there is no centralized system available, get an air conditioner or cooling unit that is able to keep your equipment working productively while minimizing energy consumption and costs.

    • -If at all possible, fresh air vents are great and save on energy costs and consumption!

    • -Remove any and all radiators or other heating equipment currently present in the room. You don't need to add heat at all!

    • -Monitor your cooling system(s) to make sure it is working properly, especially when no one is there.

    • -Make sure your cooling units are not too close in proximity to your electrical equipment, think condensation and flooding. Do not place air conditioning units over your servers.

    • -Monitor the humidity to prevent static charge and electrical shorts.

    • -See if a chilled water system is in the budget or find something within the budget constraints to ensure that the hot air has somewhere to go.

     

    (3) Using Your Power

    • -Check to make sure that you have enough outlets to support power to all your equipment and not to overload them.

    • -Get backup power, preferably UPS to prevent data loss from power blinking or outages.

    • -Don't surpass the maximum electrical intensity per unit of space.

    • -Consider shut down capabilities of equipment (SNMP traps for example).

    • -Make sure your equipment is grounded.

    • -Monitor for power outages if you are not using back-up power systems.

    • -Monitor your back up power systems to make sure your mission critical equipment is not failing due to power loss.

     

    (4) Keeping Secure & Safe

    • -Have at least one phone present in the room in case of emergencies.

    • -Either check for a preexisting fire alarm system and install one if there isn't.

    • -Get a fire suppression system if there is not one there. Take into consideration of whether you will have a wet or dry suppression system and the effects that will have on your equipment. (Halon is a great choice!)

    • -Have reliable contacts to help resolve issues immediately, or form a system of escalation.

    • -Monitor for flooding, especially if this has happened historically in the past.

    • -Secure entrances/exits, this is expensive equipment with critical data, you don't want just anyone in there messing around!

     

    (5) Other Considerations

    • -Get the best cabling/wiring available within budget constraints. 

    • -Keep extra cabling/wiring around, because you never know when you may need it.

    • -Consider color coding wires/cables, a little more work now but definitely a time-saver in the future!

    • -Think about lighting: location & heat produced.

    • -If there is someone sharing the space, get them some earplugs! It's going to be loud in there with the equipment being used.

    • -Consider networking/phone lines being run in there and how much space you have left after that.

    • -Plan for future expansion or retrofitting (again).

    • -Leave the service loops in the ceilings.

    • -Label outlets.

    • -Get rid of dust, your equipment hates it!

    • -Check if you have a rodent/pest problem.

    • -Cover emergency shutoff switches so that it can't be accidentally triggered.

    • -Try to centralize the room in the building so that you can eliminate having to use more cabling/wiring than you need to.

    • -Meet OSHA and ASHRAE guidelines as well local codes.


    Is your server room or do you know of someone's server room that is not being monitored for temperature? Are you concerned with energy consumption, ability to monitor off-hours, and/or preventing mission critical equipment from failure? If you or know someone who is experiencing such issues, we want to hear form YOU!

    We will be giving away ONE FREE USB DEVICE per month to the server room with the most need! Valued at $129.99,Temperature@lert USB Edition is a low-cost, high-performance device that monitors the ambient temperature in your server room and alerts you via email when the temperature rises or falls outside your acceptable range.

    Please send a brief description, pictures, and/or videos to diane@temperaturealert.com for consideration! Our team will select one winner each month based on description and need, because we firmly believe that companies in every industry 


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  • The awards just keep coming! Michelle Keefe finalist in Stevie Award competition

    We're on a roll: BBJ 40 over 40, Finalist in MassChallenge competition, 2011 Connected World Entrepreneur Award, the list just keeps growing.  And now we've learned our own Michelle Keefe, Temperature@lert's Sustainability Seer, our collective environmental conscience is a finalist for the 2011 Stevie Award for the small business category.  Stay tuned for the results! And Michelle, Congratulations! and take time for it to sink in that you're very special among the 1300 deserving entrants for this year's awards.  See our full press release about the announcement here:  Link to Press Release

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  • How many temperature sensors do I need?

    What is the temperature in the room you’re in right now?  Take a guess, you’ll be correct within a few degrees.  Now, what is the temperature of the room?  Don’t bother answering that, it’s a trick question because in fact there is no “temperature of the room”, the temperature of the room is a 3D matrix that likely varies by up to 3°C (5.4°F) from one point to another.

    In spaces as different as commercial refrigerators and data centers, temperature differences can be even greater.  Computer modeling demonstrates how, in a data center, server racks can be cool at the bottom and hot near the top.  Commercial refrigerators can have very cold areas near the chilled air outlets.  Whether or not the temperature variations are meaningful depends on what they impact.  Consider the last time you turned your refrigerator down a little and noticed the next morning the milk container in the direct blast from the cooled air outlet was partially frozen.

    Temperature@lert’s White Paper Library has an entry titled “Why isn’t the sensor reading the same as my thermostat?”   (Link to White Paper) The paper shows a room cycling through a twenty-four hour cycle in a second floor, sunny bedroom temperature differences at the floor and 6-feet from the floor can be as much as 5°F, and are never equal.  MIT’s Building Technology Group is explores design, technology and implementation of environmentally responsive urban housing in China.  Figure 1 shows temperature variations from room to room in a sustainably designed apartment.  This one plane model shows a 1°C (1.8°F) temperature difference in rooms with heat sources.



    Figure 1: Modeling temperature variations in an environmentally responsive urban home shows average of 24°C and high of 25°C.   Source: MIT Chinahousing Research  (Link to MIT China House)

    To make informed decisions about how many sensors to deploy, consider whether or not the heating and cooling sources are in direct line with sensitive materials.  Enough sensors will be needed to insure the warmest and coolest locations are within established parameters.  Too many sensors can lead to “sensor data fatigue”, having too much data.  If you’re unsure, experimenting with a few in different locations is a good start.  A balance of protecting valuable materials, cost, and variability within the space being monitored will insure that when problems occur, they are noticed.

    For questions or additional information, contact Temperature@lert at info@temperaturealert.com.

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