Showing posts with label balance. Show all posts
Showing posts with label balance. Show all posts

7 Mar 2014

Hi Indoor Quality! Hi Poor Focus! 4 Hi Key Feature Golden Rules Of Ways To Improve Winter Indoor Air Quality (IAQ)!

Hi Indoor Quality! Hi Poor Focus!
4 Hi Key Feature Golden Rules Of Ways To Improve Winter Indoor Air Quality (IAQ)!

"Poor indoor air quality becomes a much bigger issue during the winter months, primarily because we spend a great deal of time indoors with the windows tightly closed.
And that means that any indoor pollutants have less chance of escaping and have a better chance of irritating building occupants."
Because 30% of the commercial buildings in the US already have poor IAQ issues, during the winter months occupants are even more likely to suffer the ill effects of exposure –including respiratory issues and allergies – to indoor pollutants.
So now businesses are footing the bills to cover the medical expenses of sick workers and they're also incurring costs because of lower productivity. US businesses see an estimated 33% drop in worker productivity that’s directly attributed to poor IAQ, according to Buildings.com. 
 Visit Buildings.com Website For Further Reading On Article Publication Of 3 Ways To Improve Winter IAQ.
Click Link Here Or Image Above To Visit Buildings.com Website For Further Reading & To View Article Publication Of 3 Ways To Improve Winter IAQ.
- "Poor IAQ costs the US economy as much as $160 billion each year."
Here are four suggestions to help you improve winter IAQ in your building:
Open doors and windows as often as possible to reduce moisture levels and pollutants. When there is poor ventilation, pollutant levels (from cleaners, adhesives, etc.) are more concentrated, says Jennifer Meek, a customer service manager for Enviro-Solutions. See further reading on information publication article to Eliminate, Ventilate & Isolate, For Improving Winter IAQ By Sandy Smith on EHS Today website. 

 Visit EHS Today Website Article For Further Reading On Winter IAQ.
Visit EHS Today Website For Further Reading On Winter IAQ by clicking the image above or link here.

  1. Reduce the amount of chemicals used in a facility, especially those that release volatile organic compounds (VOCs). Meek recommends going through your chemical supply and replacing harsher chemicals with choices that emit fewer pollutants and VOCs.
  2. Replace the air filters on your building’s HVAC system according to the manufacturer’s recommended schedule, notes Buildings.com. When you install the filters ensure that they’re secured tightly with no gaps between the frame and rack. This is crucial because respirable particles can pass through the gap without being filtered.
  3. Select a quality filter, one that is mechano-electret, providing a balance of mechanical and electret efficiency. It should perform better than a filter that only uses mechanical efficiency as the electrostatic effects can better capture the submicron particles that can cause health issues.

Improved IAQ can have a great impact on work performance, while reducing absenteeism and healthcare issues, according to Robert Martin, an associate category manager for Kimberly-Clark Professional Filtration. Martin also claims the proof is in the statistics
 – better IAQ reduces respiratory illnesses by about 76% and improves employee productivity by about 20%.
Hi Focus Industry Shift Towards Sustainability Reporting!
Now moving on IAQ and shifting the focus on highlighting Regulators & Code Standards Of Industry Requirements & Implications, We ask will G4 simplify Sustainability Reporting?

Will G4 simplify sustainability reporting? The Global Reporting Initiative (GRI) seems to think so.
GRI is one of the most well-known organizations in the sustainability field
The group promotes sustainability through offering reporting tools to organizations to help them become more sustainable.
GRI believes a sustainable global economy should offer profitability in conjunction with ethical behavior, environmental care and social justice.
GRI recently released its G4 Sustainability Reporting Guidelines as an update to G3, which was first introduced in 2006. Visit The Global Reporting Initiative Website by clicking the link above or image below to view detailed information on the G4 sustainability reporting guidelines and much more details. 
 Click Here To Visit The Global Reporting Initiative Website
Click link here or image above to visit the website & view further detailed information on the G4 sustainability reporting guidelines. 
Much has changed in the sustainability world, making the G4 release greatly anticipated, especially considering that other sustainability reporting standards were released in the past seven years, drastically changing sustainability reporting.
GRI’s reporting system lets companies measure and communicate their sustainability information. GRI’s mission is to make sustainability reporting a standard practice.
- "The organization’s sustainability reporting framework is used widely throughout the world."
The sustainability reporting offers methods and metrics that measure and report sustainability performance. A company’s published report details the environmental, economic and social impacts caused by its everyday activities.
It also exhibits the organization’s values toward sustainability and its commitment to a sustainable economy. 
A report can help build trust with stakeholders and others, offering transparency and accountability.
The reporting guidelines are developed in a process that involves representatives from civil society, labor, business and financial markets. 
Additionally, auditors and experts from various fields offer their expertise, and GRI works closely with government agencies in different countries.
G4 includes G4 Online, a free-to-use, web-based tool to help organizations prepare sustainability reports.
GRI believes its latest guidelines will increase user-friendliness and accessibility. 
The emphasis in G4 is on encouraging organizations to provide only the information critical to their stakeholders. 
GRI says the reports will be more strategic, focused and easier to navigate.
According to GRI, the key improved features in G4 include:
  • Up-to-date disclosures on governance, ethics and integrity, supply chain, anti-corruption and greenhouse gas emissions.
  • Generic format for disclosures on management approach.
  • Two “in accordance” criteria options, both focused on material aspects.
  • GRI Content Index offering a transparent format to communicate external assurance.
  • Technically reviewed content and clear disclosure requirements.
  • Detailed guidance on how to select material topics, and explain the boundaries of where material impacts occur.
  • Flexibility for preparers to choose the report’s focus.
  • Flexibility to combine with local and regional reporting requirements and frameworks.
  • Up-to-date harmonization and reference to all available and internationally accepted reporting documents.
  • Overview tables, summaries and quick links to the specific components of the guidelines.
  • Complete glossary, reference lists, and visual guidance.

As previously advised for Further Reading Read more about GRI’s G4 sustainability reporting.

16 Oct 2012

Hi My Mechanic Re-visited!.

Hi My Mechanic Cooling Tower Revisited:


System Calculations

To properly operate and maintain a cooling tower, there needs to be a basic understanding of the system water’s use. Water use of the cooling tower is the relationship between make-up, evapora- tion, and blowdown rates. There are a couple simple mathematical relationships between the blowdown rate, evaporation rate, make-up rate, and cycles of concentration of a cooling tower that are very useful to understand the principal flow rates. 

The first relationship illustrates the overall mass balance consideration around a given cooling tower:

(1) Make-up = Blowdown Evaporation
In this case, the blowdown accounts for all system losses including leaks and drift, except for evaporation.
The second principal relationship defines cycles of concentration in terms of make- up flow and blowdown flow:
(2) Cycles of Concentration = Make-up ÷ Blowdown
This equation can be rearranged to either of the following to solve for the make-up rate or blowdown rate:
(3) Blowdown = Make-up ÷ Cycles of Concentration
(4) Make-up = Cycles of Concentration × Blowdown

If the evaporation rate and cycles of concentration are known, the blowdown rate can then be determined by substitut- ing equation 4 into equation 1: 


(5) Cycles of Concentration × Blowdown = Blowdown + Evaporation
Solving for blowdown:
(6) Blowdown = Evaporation ÷
(Cycles of Concentration -1)

Also, if the blowdown rate and cycles of concentration are known, the make-up rate can be determined by solving equation 4, and then the evaporation rate can be determined by solving equation 6 for evaporation:

(7) Evaporation = Blowdown × (Cycles of Concentration – 1) 


System Concerns

Cooling towers are dynamic systems because of the nature of their operation and the environment they function within. Tower systems sit outside, open to the elements, which makes them susceptible to dirt and debris carried by the wind. Their structure is also popular for birds and bugs to live in or around, because of the warm, wet environment. These factors present a wide range of operational concerns that must be understood and managed to ensure optimal thermal performance and asset reliability. Below is a brief discussion on the four primary cooling system treatment concerns encountered in most open-recirculating cooling systems.


Corrosion:
Corrosion is an electrochemical or chemical process that leads to the destruction of the system metal- lurgy. Figure 7 illustrates the nature of a corrosion cell that may be encountered throughout the cooling system metal- lurgy. Metal is lost at the anode(3) and deposited at the cathode.(4) The process is enhanced by elevated dissolved mineral content in the water and the presence of oxygen, both of which are typical of most cooling tower systems. 



Figure 7. Example of a Corrosion Cell.




There are different types of corrosion encountered in cooling tower systems including pitting, galvanic, microbiologically influenced (Figure 8), and erosion corrosion, among others (expanded


discussion is available at www.gewater. com/handbook/cooling_water_systems/ ch_24_corrosion.jsp). Loss of system metallurgy, if pervasive enough, can result in failed heat exchangers, piping, or portions of the cooling tower itself.


Figure 8. Microbiologically Influenced Corrosion (Source: Taprogge GmbH).





Scaling;

Scaling is the precipitation of dissolved minerals components that have become saturated in solution. Figure 9 illustrates calcium carbonate scale collecting on a faucet head. Factors that contribute to scaling tendencies include water quality, pH, and temperature. Scale formation reduces the heat exchange ability of the system because of the insulating properties of scale, making the entire system work harder to meet the cooling demand. An expanded discussion for scaling is available at the following link; click here.






Figure 9. Calcium Carbonate Scale (Source: Hustvedt).






Fouling;


Fouling occurs when suspended particles fall out of solution forming deposits. Common foulants include organic matter, process oils, and silt (fine dirt particles that blow into the tower system, or enter in the make-up water supply). Factors that lead to fouling are low water velocities(5), corrosion, and process leaks. Fouling deposits, similar to scale deposits, impede the heat exchange capabilities of the system by providing an insulating barrier to the system metallurgy. Fouling in the tower fill can plug film fill reducing the evaporative surface area, leading to lower thermal efficiency of the system.

Microbiological Activity;
 

Microbiological activity is micro-organisms that live and grow in the cooling tower and cooling system. Cooling towers present the perfect environment for biological activity due to the warm, moist environment. There are two distinct categories of biological activity in the tower system. The first being planktonic, which is bioactivity suspended, or floating in solution. The other is sessile biogrowth, which is the category given to all biological activity, biofilms, or biofouling that stick to a surface in the cooling system. Biofilms are problematic for multiple reasons. They have strong insulating properties, they contribute to fouling and corrosion, and the bi-products they create that contribute to further micro-biological activity. They can be found in and around the tower structure, or they can be found in chiller bundles, on heat exchangers surfaces, (see Figure 10), and in the system piping. Additionally, biofilms and algae mats are problematic because they are difficult to kill. Careful monitoring of biocide treatments, along with routine measurements of biological activity are important to ensure bio-activity is controlled and limited throughout the cooling system.(6)

Figure 10. Biofouled Heat Exchanger (Source: Taprogge GmbH).
(3) The anode in a corrosion cell is defined as the site where metal is lost from the system structure and goes into solution.
(4) The cathode in a corrosion cell is defined as the site where the metal lost at the anode is deposited.
(5) Low water velocities may occur in poorly designed or improperly operated heat exchangers, in the cooling system piping, or in locations across the tower fill where uniform distribution is not maintained.

(6) Beyond the operational and mechanical problems bioactivity causes in cooling tower systems, there is a human health issue if the system develops a specific bacterium known as Legionella. For more information regarding Legionella and Legionnaires’ disease go to www.cdc.gov/legionella/patient_facts.htm.


DECSA INSTALLATIONS REVIEW:

Closed circuit coolers
RIKSHOSPITALET HOSPITAL
VERONA GENERAL WAREHOUSE
ENI OIL COMPANY
BANCO DE ESPANA
ABB POWER SYSTEM

Centrifugal cooling towers
PRINCIPESSA SOFIA
INTESABCI BANK
NOYFIL TEXTILE FIBERS
TAMPEY SUBWAY
FERRARI
AGIP OIL CO.

Axial Decsaplast
MOPLEFAN
ELEOURGIKI OIL CO.
ZAMBELLETTI PHARMACEUTICAL CO.
FORD MOTOR CO.
BOEHRINGER PHARMACEUTICAL CO.
CROW CORK CO.

Metal axial towers
INTESABCI BANK
LEONARDO DA VINCI AIRPORT
SSAB STEEL MILL
UNDERGROUND SHOPPING CENTER
ST MICROELECTRONICS
FERRERO CHOCOLATES






 Hi MiMechanic Fans Revisted:

Fan Efficiency, An Increasingly Important Selection Criteria:

The Importance of Fan Efficiency:

Why is fan efficiency so important? As a general rule, successive generations of electronic enclosures such as personal computers, telecommunications cabinets, as well as system routers, pack increasing functionality into smaller and smaller spaces. Accompanying this trend is the need to remove ever higher levels of heat energy from within those enclosures. Thermal engineers will often force air through a system using fans to regulate the internal temperatures; however as the aerodynamic performance increases so will input power.
In modern day equipment racks it's not uncommon for the total fan load to be a significant factor in the system's power budget. Coupled with the advent of equipment efficiency legislation and a growing awareness of cost of ownership, fan efficiency is becoming a critical selection parameter. Engineers now need to gain an understanding of fan efficiency, balancing it against more familiar metrics such as airflow and noise.

Understanding Fan Static Efficiency:

Fan manufacturers typically provide static efficiency as the value of efficiency, while total efficiency includes the outlet velocity term. Fan total efficiency is calculated using total pressure. Static efficiency is calculated using only static pressure.
Positive static pressure is created as a fan moves air through a system. Negative static pressure is what all other components in the airflow path create as they resist air movement. Different fan types will generate different airflow values while creating a positive static pressure to balance the negative static pressure caused by system obstructions. The fan performance curve (see Fig 1) is a representation of the airflow (X axis) that a particular fan type produces to overcome given static pressure values (Y axis).
Total pressure is the summation of static pressure and outlet velocity pressure. Outlet velocity pressure does not contribute to a fans ability to remove system heat energy; therefore it's not normally included in fan efficiency calculations.

Calculating Fan Efficiency:

As with any energy converter, efficiency is the ratio of input and output power:-

Fan efficiency = Pout / Pin
Fan input power (Pin) is:-
Pin (Watts) = V <Volts> x I <Amps>

Fan output power (Pout) or airpower using Metric units is:-
Pout (Watts) = Air pressure <m3/sec> x Air flow <Pascal's>

Using standard units the formula becomes:-
Pout (Watts) = (Air pressure <inch H2O> x Air flow <cfm>) / 8.5

Example:-
A 48V fan drawing 1A working at an operating point of 200 cfm and 0.5 inch H2O
Pin = 48 x 1 = 48 W
Pout = (200 x 0.5) / 8.5 = 11.76 W
Fan efficiency = 11.76 / 48 = 0.245 or 24.5 %

The Fan Efficiency Curve:

Fan efficiency varies dramatically as a function of aerodynamic loading. Because airpower is the product of flow and pressure, a fan working in the free air condition (no backflow pressure) has zero pressure and thus is producing no airpower and by definition has zero efficiency. Similarly, a fan in the fully shut off condition (no flow) has zero flow and is also producing no airpower and zero efficiency. The peak efficiency of an axial fan typically occurs at a pressure point of 1/3rd the maximum pressure.

Figure 1 below represents a performance plot of a 120mm size axial fan with curves for both airflow and efficiency.

Figure 1: Pressure vs. Flow Curve - 120mm Axial Fan

As a general rule, fan efficiency increases with blade diameter and speed. Fan manufacturers are now focusing on higher efficiency fans, resulting in new designs with significantly increased peak efficiency compared to older designs. Table 1 provides an indication of peak efficiency values for different standard axial fan sizes and the comparative improvement with newer generation designs.


Table 1: Axial Fans Typical Peak Efficiency;


Form FactorOldNew
40 x 4010%25%
60 x 6014%30%
80 x 8016%33%
92 x 9218%35%
120 x 12024%40%
172 round35%45%

Fan Selection Taking Account of Efficiency:

Historically, fans were chosen by finding a standard form factor to occupy the available space and then matching airflow performance against system requirement; typically using free flow as a figure of merit. This approach has the potential for missing significant power savings which could be realized by carefully matching fan efficiency to the system operating point.
In the example shown below, (Fig. 2), selecting the fan based upon free air performance would favor the high flow fan option. Overlaying the system resistance line on the performance curve shows the high flow fan would achieve the required performance of 110cfm at 0.48 inch H2O.
However, comparing this fan efficiency at the operating point against an alternative lower free air flow fan design, it can be seen the second design would actually provide higher efficiency while still meeting the duty point.
Figure 2: Pressure Vs. Flow Curve with Fan Efficiency and System impedance

Benefits of Selecting High Efficiency Fans:

Higher levels of power are required to cool the large amount of heat generated by today's high end servers. As a result, more electrical power will be needed to be allocated to the system's cooling components. In some instances, 25% or more of the total power budget for a high end rack system is allocated to the cooling fans.
Using high efficiency fans has a cascade effect on system design. Power supplies can be down sized saving weight and space and the fans power distribution network can be minimized.
The long term benefit of specifying high efficiency fans is a reduction of ownership costs. Large data centers can contain tens of thousands of servers with anywhere between 10 and 50 fans in each.
A few percentage points improvement in the efficiency of every fan installed can quickly represent many thousands of dollars in annual energy savings.
High efficiency fans can be more costly than older fan types, and this can be seen as a deterrent. Engineers and purchasing managers should understand the wider implications of using these newer fan designs.
System level savings can result from the lower power requirements and substantial energy savings can be realized by the end user.

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