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NEWS | SPRING 2016



If you haven’t already, add HVAC maintenance prevention to your list of spring building items to be completed. Why? Cooling unit service teams are at their busiest during the summer, which is, of course, the worst possible time for your building’s AC to stop working.

So, before Baltimore’s humidity and real heat kick in for the summer, have technicians check for system functionality, and for each unit’s SEER (seasonal energy efficiency ratio) rating. If SEER ratings are low (or if units are ten-plus years old), it may be more cost effective to upgrade your unit.

In addition, HVAC units’ parts should be thoroughly cleaned each spring, including:

* Condenser and evaporator coils
* Condensate pans
* Blowers
* Fan blades
* Compressor checked for charge, and refrigerant leaks
* Check dampers for proper operation of linkage

Dirty coils decrease performance and increase energy consumption, affecting the airflow of a system and resulting higher building operating costs.

Removing accumulated dust and debris from the condensate pans (before HVAC units are running full-time during the summer months) is critical: otherwise drain lines may become clogged. As well, if condensate pans are rusted, these can be treated, to slow the oxidization process, extending the life of the pans (and saving cost of replacement).

According to the EPA, cleaning dirt lodged on blowers and fan blades can significantly improve the volume of air a blower can move. Only trust a trained technician that knows not to displace any of the balancing weights clipped to the fan blades.

The EPA provides guidelines and forms to use for HVAC unit preventative maintenance. Click here to go to the EPA website for the short checklist.


How-to Guide: Cleaning Coils



During warm weather, HVAC coils cool, condense and condition air driven via ductwork throughout a facility. And, each coil’s ability to cool air to the facility manager’s preferred temperature is directly related to cleanliness. 


Inadequate preventative maintenance reduces coil effectiveness and needlessly elevates energy consumption.

Coils are usually located downstream from filters within an HVAC system. 

The first step for cleaning coils is to use an alkaline detergent to break up dirt and biofilm without causing corrosion or damaging the aluminum coil fins.

After cleaning, if there is heavy buildup on the coil, use an acid based coil cleaner to break down the scale deposits. Then, have a technician take static readings to determine the clean static delta; this data should be used as the new baseline for future coil cleanings. 

Be sure to retain coil cleaning maintenance documentation; these records will be valuable if indoor air quality issues (e.g., employee complaints) arise.

Coil cleaning is not just advised by Sagamore! Regularly scheduled cleaning of HVAC coils is recommended by The American Society for Heating, Refrigeration and Air-conditioning Engineers (ASHRAE); the U.S. Environmental Protection Agency (EPA); the National Fire Protection Agency (NFPA); and the National Air Duct Cleaners Association (NADCA).

The articles on this News page are from Energy News, Sagamore's quarterly e-newsletter:

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Did You Know?

8 Ways to Save $ 

The U.S. Department of Energy recommends these HVAC preventative maintenance procedures (energy savings in percentages):

1. Adjusting sequence of operations: 25-30%
2. Cleaning coils: 5-15%
3. Changing dirty air filters: 10-15%
4. Removing  condenser coils scale: 25-30%
5. Adjusting air/fuel ratio of burners: 15%
6. Cleaning burner assembly: 15%
7. Removing soot from fire side of burner: 9%
8. Eliminating belt slippage and pulley alignment: 15-20%


Calculate the Savings of Ceaning Coils


Who knew? Coil-cleaning is one HVAC preventive maintenance program that not only cuts energy costs, but its value can be accurately quantified.


More than ever, facility managers have to balance meeting the comfort needs of tenants or employees, versus the rising costs of energy and strained budgets. This is especially true when evaluating new projects and maintenance programs. 

Being able to measure how preventative maintenance (such as cleaning coils) saves money, may also make energy-saving upgrades possible that otherwise may be approved due to budget constraints.

ASHRAE calculates clean-coil energy savings using the change in static pressure, and other variables (e.g., current energy costs), to predict the net gain in system performance.

More specifically, coils come with design specifications indicating the expected amount of flow loss as air passes through the coils. This air loss is called static pressure loss or DP. For instance, a new cooling unit may have a design specification of 0.5 inches of water (as measured across the coil using a magnahelic gauge). The DP is calculated by measuring the difference between the airflow upstream and downstream of the coil. 

Using ASHRAE’s method, the energy savings related to coil cleaning can then be calculated using these factors:

* Post-cleaning DP of coils
* Air volume
* Number of HVAC system operation hours
* Amount of electricity in kilowatt-hours
* Price per kilowatt-hour

For example: A typical business may operate its HVAC system for 16 hours per day, five days a week (52 weeks each year), for a total 4,160 operating hours per year. 

Then, let’s say (before coil-cleaning): the average volume of the system is 1000 CFM, and the pressure drop across the coil is 1.5 inches of water. Post-cleaning, the pressure drop was 1.0 inches. 

Based on a very conservative kilowatt-hour charge range of $0.0680 to $0.0700, the cost to operate the dirty coil at 1.5 inches of water (for the entire year) is $12,483.00. Conversely, air flow of a clean coil operates across only 1.0 inches of water, costing $8,429.00: a $4,054.00 savings.

A key thing to note is that when a coil needs cleaning, there may be no specific change in DP. Therefore, including coil-cleaning as part of routine preventative maintenance will likely pay for itself (and then some), freeing up operating funds for other projects.

Source: Cochrane Ventilation




Integrate Your Plans For Energy & Maintenance


Maintenance and energy management are two sides of the same coin

By Patrick O'Donnell


Recently I inspected a building with carbon dioxide (CO2) sensors for monitoring outside air. Due to high CO2 concentrations indoors, the building required high levels of outside air for ventilation. The sensors were intended to help the system pump optimal volumes of outside air into 

the building to maintain an ASHRAE-mandated maximum concentration of indoor CO2 at 700 parts per million over the outside level. Too little outside air would lead to possible discomfort for occupants; too much would consume unnecessary energy.

However, the CO2 sensors were located downstream of the outside air, allowing indoor air to interfere with the sensors’ readings. During system startup, testing, and balancing, no one had recognized that fact. As a result, the building owner’s significant investment in the sensors was being wasted. 

You can avoid such problems if you think of energy management and maintenance as two sides of the same coin and integrate your plan for each. Nevertheless, I still encounter the "if it’s not broke, don’t fix it" mentality, i.e., clean the condensate drain and change the filters now and then. Rising energy costs and green mandates no longer allow this approach.

Your energy/maintenance plan should anticipate the outdoor dew point in your climate region and its potential effect on mold and mildew. For example, in hot and humid climates, shutting down the air-conditioning system at night may save refrigeration energy but lead to mold if moist outside air infiltrates the building. This recording of temperature, humidity, and dew point shows conditions that lead to condensation.

Factors for Success

To be successful, a combined energy management and maintenance plan requires a number of factors to be in place. First of all, management must be committed to establishing a plan and keeping it in place. The plan needs to be simple because a complex plan may never get launched and may never be understood by employees. Initial goals should be simple and realistic.

You will need to establish an energy baseline with your building’s Energy Utilization Index, which – for the sake of communicating the concept to all involved – can simply be known as the building’s energy appetite. Use at least a year’s worth of energy consumption data and the building square footage to calculate baseline consumption. 

Then you must track and audit your building’s energy appetite, or you won’t know the effect of carrying out your plan. The more often you track it, the better; monthly is great, but if you can’t do it so frequently, then commit to bimonthly or quarterly reports. When you have special conditions – such as a particularly cold winter, a higher concentration of occupants, or different work schedules – you will also need to track those factors. 

The plan must incorporate details about the type of HVAC system in the building. This is important because each type utilizes different controls, and you want to be sure you understand the controls and their operation. For example, a direct expansion system may have the ability to be staged when operating under part-load conditions. During HVAC maintenance, the staging control should not be compromised or bypassed. On the other hand, although staging reduces refrigeration capacity, it may not reduce total air flow, which could result in poor moisture removal. The plan should anticipate such unwanted possibilities. 

Your plan should be communicated to, and understood by, your HVAC contractor, who must accommodate the plan as well as service the equipment. For example, if a piece of equipment requires replacement, the contractor’s sales rep should be aware if you have recently installed more efficient lighting that has reduced the heat load on the building. In that case, the rep should not quote equipment with the same capacity but instead size it to current demands. 

Reprinted with permission: Buildings.com article posted on December 1, 2010



Saving Water & Energy with Cooling Towers

How can cooling towers save energy, while being major users of water? This article explains: the critical role evaporative heat transfer systems play in a sustainable environment; how water is consumed in such systems; and the strategies that help minimize the use of water and energy – lowering the operating budget overall.

The first water-cooled systems used potable water to provide heat rejection, with the cooling water wasted to a drain. Cooling towers were developed to recycle more than 98% of this water, resulting in tremendous water and energy reductions as these systems grew in size and popularity.

How can cooling towers save energy, while being major users of water? This article explains: the critical role evaporative heat transfer systems play in a sustainable environment; how water is consumed in such systems; and the strategies that help minimize the use of water and energy – lowering the operating budget overall.


The first water-cooled systems used potable water to provide heat rejection, with the cooling water wasted to a drain. Cooling towers were developed to recycle more than 98% of this water, resulting in tremendous water and energy reductions as these systems grew in size and popularity.


Evaporation
 
Evaporative heat rejection systems (open and closed circuit cooling towers, and evaporative condensers) enable system efficiencies, which conserves water at the power plant and reduces emissions of greenhouse gases and other pollutants. This is because thermoelectric power generation accounts for 38% of freshwater withdrawals in the US – essentially equal to that withdrawn for irrigation.

The primary consumption of water in a cooling tower is through evaporation, the process also used by the human body to regulate internal temperature. In a cooling tower, the warm water from the system comes into contact with the entering air, usually over a heat transfer surface such as fill. A small portion of the recirculating water evaporates, cooling the remaining flow. This process is very energy efficient as approximately 1,000 BTU (1055 kJ) are required to evaporate 1 lb. (0.454 kg) of water at standard design conditions (1,000 BTU/lb. [2,326 kJ/kg]).

The Bottom Line: Saving Energy + Water

In contrast (to evaporative heat rejection systems), air-cooled heat exchangers must move far more air to reject the same heat, consuming additional fan energy in the process. This usually occurs at a much higher system temperature since the dry-bulb temperature is higher than the wet-bulb temperature of the air. These higher temperatures result in greater energy use by the cooling system, often 30% or more as in the case of an air-cooled versus a water-cooled chiller.

By reducing the electrical energy consumed at the site, less power needs to be generated and less water is used at the power plant (and in the extraction and processing of the plant’s fuel source). For example, in some climates, the total water use (source and site) between air- and water-cooled chillers is almost equal. The lower energy use also enables a higher percentage of renewable, clean power from solar and wind at a given facility. However, energy is also required to treat and distribute the water. 

The balance between the uses of these two resources is often referred to as the “energy/water nexus.”

Today, water supplies are challenged in many areas of the world including Atlanta (recent drought) and California (current drought). Methods to conserve water include ensuring evaporative heat rejection systems use only the amount of water required to: maintain optimized system performance, minimize system maintenance, and ensure a long system life.

Source: ASHRAE



DOE's Aggressive HVAC Efficiency Standard

New rule projected to save up to $167 billion over 30 years

Recent Department of Energy (DOE) efficiency standards, regarding commercial air conditioners and furnaces, are projected to save up to $167 billion in avoided equipment-lifetime costs.

These measures will conserve more energy than any other standard from the agency to date, as well as cut emissions by 885 million metric tons over the next 30 years.


The standard affects rooftop air conditioners most commonly used in low-rise buildings such as schools, office facilities, retail, and food service establishments. The first phase takes effect in 2018: requiring an efficiency improvement of 13% on new products, with another 15% increase in efficiency being required five years after. Visit the DOE’s Office of Energy Efficiency & Renewable Energy website to learn more about the new standards for commercial package units and split systems. 

Source: Buildings.com




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 Sagamore Mechanical Services
 55 Aileron Court | Unit #1 | Westminster, MD 21157

 main phone: 410.861.6386 | service phone: 443.293.7276 | fax: 443.293.7519

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