Ventilation/IAQ
Adaptations in Data-Center Cooling
Despite inroads made by newer approaches to data-center cooling, such as close-coupled systems, in recent years, changes to industry standards, improved components, and the industry adoption of energy-efficient air management have allowed perimeter cooling (commonly referred to as computer-room air conditioners [CRACs] or computer-room air handlers [CRAHs]) to maintain its position as the most widely accepted choice for cooling in mission-critical information-technology (IT) environments. This article examines those developments....
Advanced Energy Benchmarking
Benchmarking, either internally between facilities or externally against industry standards, can help organizations achieve significant efficiency gains. This article will discuss new applications enabling easier system integration and more efficient data management, visualization, and analytics, driving significant cost savings and making possible new approaches to benchmarking....
Induced-Flow Laboratory Exhaust-Fan Systems
Independent third-party verification of ventilation-system components is valuable in ensuring performance and safety. This is especially true for critical laboratory exhaust systems....
Applying DOAS With Heat Pipes
Combining heat pipes and dedicated outside air creates reliable, energy-efficient, low-maintenance systems....
Green Innovations in Underfloor Air Distribution
A properly designed UFAD system takes advantage of thermal stratification. The key is to have a diffuser that rapidly mixes air before it penetrates the stratification layer at the upper end of the occupied zone. The pressurized plenum (the area between the slab and the raised floor) essentially is a large duct maintained at a constant pressure differential—typically, 0.05 to 0.10 in. w.g.—to the room above. This pressure is maintained through the supply of conditioned air from a number of supply-duct terminations...
Reducing HVAC Noise With Duct Liner
Understanding the acoustical benefits of duct liners and the available choices in liner materials helps in specifying a system that is efficient and effective, both in terms of noise performance and HVAC performance....
Single-Zone, CO2-Based Demand-Controlled Ventilation
This article will clarify the relationship between CO2 level and ventilation rate and offer suggestions for improving traditional single-setpoint CO2 DCV through the addition of a direct outdoor-airflow-measuring device....
Destratifying Heat With Large-Diameter, Low-Speed Fans
Blending stratified warm and cool air through the use of large-diameter, low-speed fans eliminates the draft associated with typical fan circulation to achieve a comfortably heated space....
Basic Fan Selection
Selecting a fan can be fairly complex. This article outlines the basic process for matching a fan to a system: Define the application. Select the basic...
Three Keys to Hydronic Control
All HVAC installations should try to reach two fundamental objectives. First, they should deliver the specified comfort level. Second, they should reach...
Design of a Specialized Airborne-Infection-Isolation Suite
A biocontainment patient-care unit (BPCU) is a facility designed and operated to maximize patient care with appropriate infection-control practices and procedures. A BPCU is secure, is physically separated from other patient-care areas, and has special air-handling systems.1...
Building Ventilation and the Principle of Diversity
Applying diversity principles to total ventilation requirements saves a significant amount of money and energy...
Making a Case for Reduced Classroom Ventilation
Across the United States, a minimum of 15 cfm of fresh air per student is required for classroom ventilation. That is the amount set forth in ANSI/ASHRAE Standard 62.1, Ventilation for Acceptable Indoor Air Quality (IAQ), and it is the minimum amount the U.S. Green Building Council (USGBC) will recognize through its LEED green-building certification program. In fact, the USGBC will award additional credit if 20 cfm of fresh air per student is delivered....
Predicting the Performance of Flexible-Duct Systems
We rely on information and calculation methods we assume have a firm foundation in reality only to sometimes find they do not. That is what happened in 2005, when, asked by an attorney to investigate the failure of an HVAC system to provide the owner’s expected comfort conditions, I reviewed design drawings and calculations and built a mockup of a flexible-duct system....
Ceiling-Mounted Air Conditioner Chosen to Cool Health Clinic's Data Room
At Allina Medical Clinic in Forest Lake, Minn., temperatures in the 10-ft-by-12-ft data room, which houses network switches and other computer and telecommunications equipment the clinic depends on for day-to-day operation, were high, but acceptable. That changed with the installation of additional switchgear and computer equipment and a larger uninterruptible power supply. ...
Data-Center Uptime & Energy Efficiency
Many data centers are "mission-critical," meaning essential to the core function of an organization. As such, they must remain operational at all times. However, that does not mean significant improvements in energy efficiency and sustainability cannot be made....
Large-Diameter, Low-Speed Fans Ensure Comfort, Reduce Energy Use in Gym
Seeking a way to keep members comfortable without increasing the tonnage of its air-conditioning units, Fitness Connection installed several Element and Isis large-diameter (8 to 20 ft), low-speed, commercial-grade fans from Big Ass Fans....
Air-Filter Life-Cycle Cost
Properly maintained, the main components of HVAC systems—coils, fans, casings, controls—should last 20 years or longer. One component that has a major impact on the cost of maintenance, the lifetime of other components, energy use, and the protection of building occupants and processes, however, is considered disposable: the air filter....
Fan Selection and Energy Savings
HVAC design engineers face many choices throughout the planning process, perhaps few as crucial as that of fan equipment, a principal consumer of energy. This article will discuss options for improving energy efficiency when designing an HVAC system and selecting a fan....
Low-Cost Dedicated Outdoor-Air Systems
The concept is straightforward: Condition and deliver fresh ventilation with a dedicated outdoor-air system (DOAS) to treat outdoor air and space latent loads efficiently. ...
The Benefits of Ice-Based Thermal Energy Storage
Is ice-based thermal-energy storage (TES) really green? Although the success of ice-based TES in reducing energy costs has been substantiated, there are differing opinions within the HVAC community regarding whether TES is a green technology....
Test Tool and Power Logger Help Make the Case for Law-School HVAC Upgrade
In Columbus, Ohio, a six-story law-school building requires cooling year-round. "A lot of buildings we can cool with outside air," Mike Klingler, service manager for HVACR contractor Farber Corp., said. "When we get down to 50 to 52°F and below, we can just draw that outside air in and use it for free cooling. But because of the setup of the law-school building, they had to run one of the chillers even when it was 20 to 25°F outside. Because of the duct distribution system, we couldn't rely on outside air in certain areas of the building." ...
Large-Diameter, Low-Speed Fan Solves Air-Movement Problems in Housing Office
Located on the campus of the University of Nevada, Las Vegas, Tonopah Residence Complex is a six-story residence building and home to the Office of Housing Services. In the lobby, air-circulation problems were making conditions uncomfortable for the dozen employees who work there and the continuous stream of students who pass through to pay bills or make housing inquiries....
The Case for Increased Ventilation
Facilities managers have at their disposal a proven and effective means of helping to contain employer health costs: increasing ventilation. This article will discuss how increased ventilation can prevent the spread of disease among workers in commercial and government office buildings....
School District Betters Indoor-Air Quality While Reducing Outside-Air Requirements
At a recently rebuilt three-story high school in the North East Independent School District (NEISD) in San Antonio, the outdoor-air-supply duct serving...
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