Green Notes

SearchDatacenter.com recently had a great article by Bob McFarlane with several handy tips on sizing computer room air conditioners and save on energy. Here are some excerpts:

Sizing a data center air conditioner is not like choosing a refrigerator. Bigger is not necessarily better! Correct sizing is even more critical to effective operation and energy efficiency than right-sizing the uninterruptible power supply (UPS). But with so many factors that determine capacity, it can be a bit tricky.

 

When someone plays with the thermostat at home (not you of course!), the temperature is never right. It gets too hot, then too cold. It’s worse with computer room air conditioners (CRACs). The unit that’s the wrong size can mess up cooling. Wrong settings or improper location will make it even worse.

 

Under-sizing can’t cool effectively — that’s obvious. But over-sizing won’t either. Thankfully, many CRACs will adjust to a range of loads, but there are many that won’t. They all need to be sized realistically, but over-sizing will always result in cooling going on and off too often. It’s called “short cycling,” which is hard on the machine and does a lousy job of maintaining room temperature and humidity. Yes, temperature swings do hurt computing hardware!

Air conditioners have to deal with two kinds of heat. Sensible heat — the kind we can feel — is what our computers give off. Latent heat is what evaporates moisture. Simplistically, dealing with moisture or humidity requires more latent capacity from our air conditioners, which steals from sensible capacity. There’s not much reason to keep a data center above 45% relative humidity (RH), but if you over-cool you’ll pull moisture out of the air (latent cooling) and have to use more energy to re-humidify. The problem is that relative humidity is “relative” to temperature. Warmer air has a lower relative humidity for the same moisture content because it can hold more vapor than cool air. Temperatures in a data center vary widely, so RH depends on where it’s measured, which is why we’re trying to get away from using it. However, RH is still the most common way to determine humidity.

Thankfully, today we can use variable frequency drives (VFDs) to automatically adjust fan speeds for appropriate air flow, controlled by sensors in the room. These can be retro-fit to most existing CRACs, and can save a lot of energy. (A professional computational fluid dynamics, or CFD, analysis is a good idea before buying any expensive air conditioner.)

So Step 1 is to know your real loads. Step 2 is to see if you can get higher temperature return air back to the CRACs. Step 3 is to decide cold air temperature. The American Society of Heating, Refrigeration & Air Conditioning Engineers (ASHRAE) Technical Committee 9.9 has recently increased the temperature envelope, so there’s no need to over-cool the equipment. Step 3 is to set your humidity standard. ASHRAE TC 9.9 now recommends dew point monitoring and control, but existing CRACs may not be able to do that, so you’ll still need to control relative humidity. Then, if possible, pick an air conditioner that can adjust to load and choose a sensible capacity that will operate Day 1 in its midrange. That will give the best stability and control.

Let’s look at three other important issues before we finish: reheat, humidification, and water temperature. If you have more than three or four CRACs, it should not be necessary to put humidifiers on every unit. Moisture diffuses and stabilizes in the room pretty quickly (another reason for dew point sensing). Putting humidifiers on every air conditioner can be counterproductive if one unit humidifies while another de-humidifies. That’s wasted energy for no better result.

Reheat was the norm for years, and it’s the biggest energy waster of all. The CRAC over-cools the air and a heater warms it back up to discharge temperature. In many situations it’s possible to design without reheat, or to use minimal reheat. But it takes a knowledgeable engineer to make that determination and to provide a proper design.

If you’re using chilled-water computer room air handlers, you’ll need to have a knowledgeable engineer involved. Published capacity ratings are based on specific entering water temperature and water temperature rise. Chiller plants today may be designed on higher numbers to improve energy efficiency, but that reduces the effective cooling capacity of the CRAHs.

For the full version of the original article, visit  http://searchdatacenter.techtarget.com/tip/0,289483,sid80_gci1371079,00.html?track=sy185# . Free Registration might be required on the site to view content . To know more about Green Rack Systems and the suite of services we offer in addition to sustainable cooling practices for Data centers, contact us at sales@GreenRackSystems.com .

At Green Rack Systems, we have been saying for a long time how this emphatic shift towards clean energy is inescapable. A November study by AFCOM finds that “greening of the data center is no longer just a concept – it is actually taking place”, and on a large scale, with 71.3% of all survey respondents indicating that they are actively engaged in Greening. Now, thanks to Executive Order 13514 requiring rigid energy efficiency targets, even Federal agencies have to follow what they preach by taking the lead on reducing greenhouse gas emissions by 2020. Further, they will have to divert 50% of their waste by 2015 and arrive at a net-zero energy building requirements by 2030 for all of its 500,000 buildings. This will be made possible by key changes made in their massive IT departments, servers and data centers. The laudable target of net-zero for their buildings would be impossible to achieve without adopting efficiency strategies that we have been discussing about in our previous blogs, such as virtualization, renewable energy, alternative cooling methods, energy tracking technology etc. The new initiative also dictates that 95% of new acquisitions must be Energy Star or Federal Energy Management Program compliant, be EPEAT certified, contain recycled content, or otherwise be more sustainable than other products

  Some specifics of the order include:

Procurement preference for EPEAT- registered electronic products;

Policy implementation to enable power management, duplex printing, and other energy-efficient or environmentally preferable features on all eligible agency electronic products;

Environmentally sound practices in case of agency excess or surplus electronic products;

Procurement of Energy Star and FEMP designated electronic equipment;

Best management practices for energy-efficient management of servers and Federal data centers.

Cost-effective, innovative strategies, such as highly reflective and vegetated roofs, to minimize consumption of energy, water, and materials;

Reduction in the the consumption of energy, water, and materials, and identifying alternatives to renovation that reduce existing assets’ deferred maintenance costs.

Find opportunities while procuring real estate to consolidate and dispose of existing assets, optimize the performance of the agency’s real- property portfolio, and reduce associated environmental impacts

Rehabilitation of federally owned historic buildings utilizes best practices and technologies in retrofitting to promote long- term viability of the buildings.

In addition to the above, the directive advices employees to consider alternatives to traditional commuting and business travel such as telecommuting, web meet technologies etc.

The above practices are implementable for any office or data center outside of the governmental offices that it meant for. Now with Washington setting definite, targeted goals for itself in the green department, commercial enterprises who have lagged behind would very soon have no choice but to follow the lead.

While it is natural to immediately gravitate towards hardware and energy centric dimensions of sustainability, eco- friendly computing in terms of the software used, applications and services tends to be an afterthought. Sure, there are software tools that help track emissions, provide better storage solutions, monitor alternative energy production, smart energy grid management etc but what about the actual software used? Can software be green in itself , apart from its functionality?

One way to go green on the software would be to choose a low resource version of open source software .Why? Open source is software for which the source code is completely accessible allowing users to use, change, and improve the software. The customization and free code help with resource optimization and cost reduction. Open source also tends to have a strong community backing of developers who collaborate on the development process further increasing efficiency and reducing work time. Since organic open source software is not tied to any vendor, it tends to be distributed online without the inherently wasteful stages in software purchase such as marketing presentations, quotes, contracts, postage material etc. E-mail transmission of documentation is also generally the norm amounting to lesser paper wastage. Use of good document management software further reduces the use of hard copy manuals. There is a significant number open source developers who telecommute as coding is mostly done in isolation lending itself better to telecommuting options which is another big energy save. Also low resource open source software can typically run on recycled equipment and less glossy hardware unlike the costly demands of most proprietary software that does not perform well on commodity hardware. Another way that your facility can contribute to energy conservation is to adopt an efficient open source, online CRM software to organize, track and maintain customer relationships. Once you have a good web conferencing software in place, there is less need for travel and expensive meet-ups for trivial matters on the pretext of finishing business.

Of course not all open source software is completely free of expense even though it does not usually come with the hefty price tags of proprietary software. Some of the commercial open source software vendors require additional fees for customer support and development. Additionally you might have to invest in one or more software engineers to help you with customization depending on the needs and size of your organization. For help with greening your IT strategy, choosing the right open source software to boost your efficiency and achieve pain free opensource migration, contact us at GreenRackSystems; sales@GreenRackSystems.com.

Cloud computing is a kind of scalable service provided by distant vendor servers over the internet. The data storage and management tasks are assigned to a set of infrastructure, platform or software over a network or “cloud”. This type of computing certainly comes with inherent flaws such as a danger of becoming too vendor dependant , a shrinking on-site IT department, questionable security and reliability issues etc. Also cloud computing requires a lot of investment which has led many detractors to suggest that this type of computing service would lead to an unfair monopoly of the big players in the business. But cloud computing is still in a stage of technological infancy, so it is only a matter of time before these concerns are ironed out.

Cloud Computing provides datacenters with immense potential to save on energy, infrastructure and staffing issues. The advantages are numerous. Smaller scale datacenters can benefit from access to sophisticated super computers leading to increased competitiveness in the market. More moneyed ventures who have the means to invest in new infrastructure, on the other hand can offer their services to others increasing their potential and diversifying their line. Computational power and storage borrowed from a third party decreases the load in your data center thereby leading to less energy consumption on the home front. Also you pay for what you use and use resources on a need to basis. Services on the host side, run on shared infrastructure at high utilization as not all users will be accessing service at the same time. Therefore there is less computer idling and a lot more of energy saving. While some argue that cloud computing just shifts the energy consumption from the data centers to the hosts’ side , even with all the additional overhead costs and single computer power usage , there is considerable decrease in net power as you take other systems offline and pay a whole lot less for cooling. When we add virtualization and alternative energy sources like solar power to the midst, we really mean green business! Green rack systems provides a high tech solar powered co-location facility as an optional service for our clients. Those intent on keeping things in house but would also like to cut down on energy bills, should consider professional third party services like ours for secondary and non-critical applications while retaining main frame operations close to home. Cloud computing is also a great way to go for startups that cannot afford to maintain a professional standard data center. Please contact us at 408-213-8144/ sales@GreenRackSystems.com for an in-depth consultation on what option would suit your business model.