ASHRAE 90.1 is a US standard that provides minimum requirements for energy efficient designs for buildings except for low-rise residential buildings. The original standard, ASHRAE 90, was published in 1975. There have been multiple editions to it since. In 1999, the Board of Directors for ASHRAE voted to place the standard on continuous maintenance, based on rapid changes in energy technology and energy prices. This allows it to be updated multiple times in a year. The standard was re-named ASHRAE 90.1 in 2001. It has since been updated in 2004, 2007, 2010, and 2013 to reflect newer and more efficient technologies. Wikipedia.
ASHRAE Journal | Year: 2014
Steven Taylor highlights some of the essential points for designing and controlling waterside economizers. To maximize performance the economizer must be integrated with the chillers, meaning the economizer has to be able to reduce the load on the chillers even if it cannot handle the entire load. The same cooling towers and condenser water pumps should be used to serve both the economizer heat exchanger and the chiller condensers. While cooling tower capacity is not affected by the economizer, it may be necessary to reduce the design approach temperature to meet Standard 90.1 Section 188.8.131.52.1 waterside economizer requirements, particularly for plants with high loads in cold weather. Cooling towers should be selected so that as many tower cells as possible can be enabled when the economizer is enabled to maximize efficiency and capacity while maintaining minimum flow rates required by the tower manufacturer to prevent scaling. The heat exchanger should be a plate & frame type and selected for an approach of about 3°F above the temperature of the condenser. Source
ASHRAE Transactions | Year: 2012
Analytical evidence and experimental results suggest that return air temperature control limits the effectiveness and efficiency of data center cooling. Return air temperature control rarely, and often only coincidentally, enables a close match of air provisioning relative to IT equipment consumption. Other methods that divorce the flow control from the temperature control offer much better opportunities to tune cooling performance, either manually or automatically, producing improvements in operational energy and capital usage. Under-floor static pressure control is one such method. This paper presents evidence that suggests that static pressure control is a viable and often superior alternative to return air temperature control. © 2012 ASHRAE. Source
ASHRAE Journal | Year: 2014
Experts shared their views on the lessons learned from the ASHRAE head quarters (HQ) renovation project. ASHRAE did its first major renovation in 1990 by gutting the interior, updating the mechanical systems, installing a new insulated glass curtain wall system, and abating asbestos materials on the interior. The reason for having three mechanical systems was to achieve the goal of creating a 'Living Lab' for ongoing research by the Society and its members. More than 1,300 points were monitored and stored on the systems and spaces in this building. The stored and real-time data were made available to the members around the world via Internet. ASHRAE expected to learn more about the long-term operation, maintenance, and performance of buildings with the various types of systems used throughout this project. Source
News Article | December 23, 2015
The Paris climate talks gave strong impetus to the world’s determination to curtail climate pollution through policies that create jobs and economic growth while simultaneously cutting emissions. While they may be a lower profile solution, improved building codes are a cornerstone of a successful climate policy. One reason for the paucity of discussion of codes is that climate policy is made on a national level, while in the United States and many other countries, energy codes are adopted and enforced primarily at the state or even local level. Nevertheless, new energy codes have the potential to save 160 MMTCE (million metric tons of carbon equivalent) of climate pollution in America by 2030–some 3 percent of emissions of the entire nation– merely by adopting model codes that already exist. Adopting the 2015 version of the International Energy Conservation Code (IECC) would result in emissions savings with an economic benefit of a quarter of a trillion dollars over the next 15 years. These savings compound over time: by 2050 the savings will be about double the savings in 2030, just because the codes apply to more and more buildings that have been constructed since 2015. Savings will also get much larger for two reasons explored next: NRDC actively works with coalitions of businesses and other nonprofits to raise the bar on energy codes. Figure 1 shows the progress of codes. Figure 1. progress of model codes in the United States The IECC code applies most commonly to residential buildings, while the ASHRAE standard is exclusively for commercial buildings. Both standards are voluntary models, but all U.S. states are required by law to adopt or consider them, and some foreign jurisdictions adopt them or modify and adopt them as well. Figure 1 demonstrates the accelerating progress we have made since the 2004-6 codes, which were hardly changed compared to 1975. From 2006 until 2012, coalitions in support of stronger codes succeeded in getting a reduction in energy use of some 30 percent. During the debate over the code for 2015, NRDC believed that there was still potential for more savings. By offering home builders something they really wanted–flexibility and the reduction of administrative burden–in return for increased savings, NRDC successfully helped to create an alternative path for homebuilders to comply with the code. The 2015 IECC contains a new tradeoff method that allows a home to meet an Energy Rating Index (ERI), the most prevalent of which is the HERS index. Using the ERI path to comply with the 2015 code requires savings of at least 45 percent compared to 2006, but allows for increased flexibility with how the savings are achieved. The ERI is like a miles-per-gallon rating for homes, in which a score of 100 means the home meets the 2006 IECC code and a score of zero means that home has no net energy consumption. Thus a score of 60 means an energy savings of 40 percent. Inclusion of the ERI is valuable to consumers: it tells the buyer how efficient the home is and how much money they should expect to spend on utility costs. The HERS score makes efficiency visible by allowing comparisons between homes. As about one-third of all new homes sold in 2014 were rated with a HERS score, there is competition between builders for a lower score. Thus, even though the tightest codes result in the average home having a HERS score of about 69, and even though most jurisdictions enforce the weaker 2009 code, the average HERS score last year was 63, showing that the existence of HERS scores on a wide basis is causing competition among builders over how much better than code their efficiency is. This year, the 2015 code has been adopted in several states, including Vermont and Maryland, and is in the process of adoption in several others. Even in states that did not cleanly adopt the model 2015 IECC building code, we still saw some progress. For example, in Texas, the largest new homes market in the country, the legislature passed a law that adopts the same prescriptive check-list of required insulation levels, etc., as in the 2015 IECC as well as the optional ERI method. While the Texas code contains ERI scores that are higher (therefore, weaker) than the 2015 model code, either method of compliance is a substantial improvement over the 2009 code. Most studies of efficiency potential answer the question of how much we would save if we used technologies current at the time of the analysis, but do not assume any improvement in those technologies. But in areas where we have tried consistently to improve efficiency through up-to-date policies, we have seen rates of improvement in energy consumption of 6 percent per year or more. The study whose results I cited abovedistinguishes itself by modeling an improvement of 5 percent for every code cycle. Code cycles occur every three years, so this is a very modest assumption. As noted above, we have been able to achieve savings of about 15 percent every code cycle since 2006. An improvement rate of 6 percent per year–which we have achieved in the California energy code since 1975–would yield a 20 percent improvement per triennial cycle. This would lead to a much larger savings projection, especially for 2050. Other areas where we have been able to achieve continual improvement rates of 6 percent annually are noted in my book, “Invisible Energy: Strategies to Rescue the Economy and Save the Planet.” In advance of the next code cycle beginning in 2018, NRDC is working with a broad variety of stakeholders both to tighten efficiency requirements by about 5 to 10 percent and to set minimum requirements for savings from efficiency alone before accounting for solar generation. Currently, it is unclear whether the version of the ERI score used in the IECC counts energy savings from solar. NRDC supports a middle-ground proposal that will allow some solar tradeoff but also guarantee a minimum level of efficiency. While investing in energy efficiency is ultimately cheaper to the consumer, there are attractive financing options and tax credits that help reduce the upfront costs to the builder of solar generation equipment and thus create a non-level playing field. NRDC fully supports efforts to increase solar power, but solar must be coupled with appropriate levels of efficiency to be most effective. This type of limited tradeoff for solar power is already being used in Vermont and Massachusetts. So far we have talked about codes in most states, which rely on national models. But California maintains its own code, which is usually more advanced than those of other states. This year the California Energy Commission adopted code upgrades that will save some 25 percent of energy use compared to the previous code, following a 2016 update that itself saves some 25 percent. We are working with the Commission and with stakeholders to assure that the 2019 California code is consistent with the state’s goal of zero-net-energy homes by 2020 (meaning the home’s total annual energy use is roughly equal to the amount of renewable energy created onsite). We are also working collaboratively with builders to try to harmonize California’s HERS system with the national system. Currently, the California system is minimally used: builders and retrofitters find it too bureaucratic. Its outputs do not agree with those of the national system, so that a HERS 80 home in California may use less energy than a HERS 65 in Nevada. While some advanced features of the California system should be retained, and perhaps extended to the national system, in other areas the two systems disagree without any good reason. This is a barrier to using HERS ratings for consumer transparency in California–a barrier we hope to eliminate in 2016. Energy codes are a powerful tool for cutting emissions and lifting the economy. NRDC plans to begin the next three-year processes of continually improving energy codes at the national and state levels and anticipates strong success in 2016 and beyond. We encourage states and cities to adopt the most current codes to maximize emissions savings and job creation.
News Article | December 22, 2015
More efficient furnaces and rooftop AC units could save 15 quads of energy by 2045. The U.S. Department of Energy announced an agreement for new energy efficiency standards for commercial furnaces and rooftop air conditioners. The federal government called the standards the largest in U.S. history for the amount of energy that will be saved: nearly 15 quadrillion BTU over the next 30 years. “They will save about the same amount of energy as all the coal burned in the U.S. to generate electricity in a year,” according to Rhea Suh, president of Natural Resources Defense Council. “These are very, very promising days in the global fight to slow, stop and reverse climate change.” Over the next three decades, the increased efficiency will cut 885 million metric tons of carbon dioxide, bringing the DOE more than two-thirds of the way to its goal of reducing carbon pollution by 3 billion metric tons. Rooftop units cool about half the total commercial floor space in the U.S., according to the DOE. A typical owner would save about $5,000 to $10,000 over the lifetime of the equipment. But the actual savings are higher for an entire AC system, as a typical big-box store may have more than 20 units. Starting in 2018, rooftop AC will have to be about 13 percent more efficient than it is today. By 2023, it will have to be 25 percent to 30 percent more efficient than current models. Commercial furnaces will have to have thermal efficiencies of at least 81 percent for gas furnaces and 82 percent for oil furnaces by 2023. Although much of the cleantech industry’s attention was focused on the spending bill and the Investment Tax Credit extension for wind and solar last week, energy efficiency advocates were heralding this announcement. “DOE is ringing in the holiday season with truly monumental energy and economic savings,” Andrew deLaski, executive director of the Appliance Standards Awareness Project, said in a statement. With efficiency advocates and industry stakeholders at the negotiating table, the DOE also made changes to how the efficiency of rooftop units would be calculated. The standard will be based on the integrated energy efficiency ratio (IEER) metric, which captures the AC’s energy use over a range of operating conditions, according to NRDC. The test procedure will also take into account total fan use, which can be a considerable chunk of an air conditioner’s total energy use. The push for standards started five years ago with DOE’s Rooftop Unit Challenge, which called on manufacturers to deliver more efficient systems — up to 50 percent more efficient than current ASHRAE 90.1 standards — at competitive prices. In 2012, Daikin’s Rebel rooftop unit system was the first to meet challenge. A year later, Carrier met the challenge. Now, five companies have units that meet the specifications. The standards will be finalized late in 2016, and little opposition is expected. Greentech Media (GTM) produces industry-leading news, research, and conferences in the business-to-business greentech market. Our coverage areas include solar, smart grid, energy efficiency, wind, and other non-incumbent energy markets. For more information, visit: greentechmedia.com , follow us on twitter: @greentechmedia, or like us on Facebook: facebook.com/greentechmedia.