1. Overview of HVAC Filtration
By: Jim Kibby

2. Outline Water Filtration in a Heat Transfer Application
Sources of Particulates
Effects of Solids Accumulation
Particle Count vs. Particle Volume
Basic Filtration Options
Filtration Equipment
Why is filtration needed in HVAC applications?
What are the different sources of these solids?
How do these contaminants affect the Heat Transfer systems?
Does particulate size and quantity matter?
What are your filtration equipment options?

3. Sources of Particulates in HVAC or Refrigeration…
Particulate deposits through make-up water
Particle contamination of HVAC systems can be found in both open and closed loop systems. * Most solids are introduced into the system through airborne entry (cooling towers), make-up water, corrosion by-products, and through precipitation of dissolved minerals (naturally occurring evaporative precipitation as well as chemically induced). These particulates most commonly include dirt, scale corrosions, iron oxides, calcium carbonate, and other suspended solids. Water quality can also play a part in the formation of these particulates.
*Cooling towers are scientifically designed air scrubbers that wash dirt out of the air and into the cooling tower water. In addition, corrosion by-products, precipitated minerals or scale are also sources of solids that are continually generated and without proper filtration build up in water cooled systems.
Particulate deposits through airborne entry

4. …Sources of Particulates in HVAC or Refrigeration
“A typical 200 ton cooling tower operating 1000 hours may assimilate upwards of 600 lbs. (272 kg) of particulate matter from airborne dust and the makeup water supply (Broadbent et al. 1992). Proximity to highways and construction sites, air pollution, and operating hours are all factors in tower soil loading.”
REF: 2008 ASHRAE Handbook – HVAC Systems and Equipment
There are many sources of airborne particulates…
-No one knows which way Mother Nature is going to blow and what she is going to bring with her;
-Solids loading may be increased due to a nearby construction site or heavy traffic.
Airborne solids alone produce a tremendous solids loading on a typical system. ASHRAE recognizes this. As noted on this slide and quoted straight from the ASHRAE handbook, “A typical…..loading” Taking that a step further, ASHRAE’s predicted 600 pounds of particulate referenced her equates to several inches of muck in the bottom of a cooling tower.

5. Solids Accumulation in Cooling Towers and Condensers
Increased bacteria growth/contamination
Legionella, other health risks
Decreased heat transfer efficiency = Increased energy consumption
More blowdown = more makeup water and chemicals usage
Higher maintenance costs and down time
There are several operational problems resulting from solids that accumulate in water cooled systems. They include:
Particulate build up creates an environment for increased bacteria growth and contamination. Posing and increased risk of Legionella and other health concerns
Solids also increase Maintenance costs and systems without good filtration often experience un-scheduled shut down time and increased costs for cleaning towers.
Dirt interferes with water treatment and increases the cost of water treatment.
Last, but not least solids can decrease heat transfer efficiency dramatically increasing energy costs.
Audience participation is key! Ask as you go through the bullets if anyone in the audience have personally experienced these to pull ownership of the discussion to the group you are presenting to.

6. Is Basin Cleaning necessary?
1/16” (1.6mm) of basin debris prevents chemicals from protecting basin (CDC statement)
Under-Deposit Corrosion Occurs
Sulfates  H2S
Metal Surface
pitting
Solids build-up and
Sulphate Reducing Bacteria
Does a car engine need an oil or air filter? Not to operate, but long term the answer is a resounding yes. The same holds true for a cooling tower. Less than 1/16” of dirt interferes with the effectiveness of water treatment with respect to under-deposit corrosion. In this vicious cycle solids build up allowing sulphate reducing bacteria to multiply unchecked. The SRB’s reduce sulphates in the water to hydrogen sulfide resulting in aggressive pitting corrosion (commonly known as under-deposit corrosion) that can decrease equipment life by as much as 75%

7. Galvanized Pan Corrosion Stainless Steel Corrosion
Under-deposit Corrosion
Galvanized Pan Corrosion
Does a car engine need an oil or air filter? Not to operate, but long term the answer is a resounding yes. The same holds true for a cooling tower. Less than 1/16” of dirt interferes with the effectiveness of water treatment with respect to under-deposit corrosion. In this vicious cycle solids build up allowing sulphate reducing bacteria to multiply unchecked. The SRB’s reduce sulphates in the water to hydrogen sulfide resulting in aggressive pitting corrosion (commonly known as under-deposit corrosion) that can decrease equipment life by as much as 75%
Stainless Steel Corrosion

8. Heat Exchanger Fouling Means Decreased Heat Transfer Efficiency
Click on the word “HX” to view the Youtube link showing a real life example of cleaning tubes!
Particulate build up leads to increased fouling.
Fouling inhibits the critical heat transfer area which leads to decreased heat transfer efficiencies.
This translates into dramatic power increases as the equipment works harder.
Increased maintenance and shut down time needed to clean the equipment

9. Typical Condenser Fouling Factors
Chillers will see different types of dirt loading based on the cooling tower location, water quality, and solids loading. You can open your chiller and measure the scale thickness with calipers to determine your level of fouling. Most often, we see customers operating well outside of the fouling factors mentioned above. Therefore, customers end up spending a tremendous amount of energy to maintain there condenser design efficiency. This can become extremely expensive as chillers already make up 40% of the energy consumption in an HVAC system.

10. Fouling Factors and Energy Costs
Standard Energy Cost Calculation For A Common Chiller
CT X KW / CT X Design Eff % X Load Factor % X Hrs of Op per Year X KW Cost / Hour = $$
CT = Chiller Tonnage
KW = Kilkowatts
Design Efficiency = 65% (typical)
Load Factor = 70% (typical)
Example:
1000 Tons X 0.65 KW / Ton X 0.7 Load Factor X 2500 Operating Hours per Year X $ 0.15 KW / Hour = $170,625 in operating costs per year. These numbers are based on a new unit with no fouling using a KW Cost /Hour for California.
Taking this value and adding the typical fouling factor of (11% power increase), the additional power needed to maintain the same system operating efficiency will increase energy costs by $18,769 a year.
Chillers will see different types of dirt loading based on the cooling tower location, water quality, and solids loading. You can open your chiller and measure the scale thickness with calipers to determine your level of fouling. Most often, we see customers operating well outside of the fouling factors mentioned above. Therefore, customers end up spending a tremendous amount of energy to maintain there condenser design efficiency. This can become extremely expensive as chillers already make up 40% of the energy consumption in an HVAC system.

11. Filtration vs. Disinfection
50 Micron 
Human Hair
(.0020”)
40 Micron 
Visibility Limit
(.0016”)
25 Micron 
White Blood Cell
(.0010”)
8 Micron 
Red Blood Cell
(.00032”)
2 Micron 
Bacteria
(.00008”)
If you have a bottle of water at this slide, use it and inform the audience that drinking water standards by the American Water Quality Association are up to 5 micron. Do you really need drinking water in your cooling system?
Here we have a few different micron sizes to give you an idea of what we need to filter. In condenser water applications, we typically try to remove all visible particles. As you can see from the chart, this would be all particles 40um and larger.

12. Particle Count VS. Particle Volume
20% 5%
20%
10–75
micron
5 microns
20%
.5 micron
3 microns
95%
10–75
micron
1 micron
20%
20%
Particle VOLUME
Even though there are the same number (quantity) of each size, the VOLUME they represent is NOT equal. The 20% that are larger particles account for 95% of the total volume.
Particle COUNT
Assume there is the same number (quantity) of each of these different sizes among the 1 trillion particles (each size is 20% of the total).
Click on the word “and” in the title to view a detailed example of particle count vs. volume LAKOS LS-775
Lets assume that the particle count in this example is evenly divided from the .5 micron contaminants, through the 75 micron contaminants. The shear size of the 10 to 75 micron particulate would represent the largest portion (in terms of volume) of the troublesome contaminants.

13. Particle Count
Click on the word “and” in the title to view a detailed example of particle count vs. volume LAKOS LS-775
Lets assume that the particle count in this example is evenly divided from the .5 micron contaminants, through the 75 micron contaminants. The shear size of the 10 to 75 micron particulate would represent the largest portion (in terms of volume) of the troublesome contaminants.

14. Size Does Matter! 5% 95% 0.5-5 Micron Particles (by volume)
Comparing the volume of Micron Particle fitting in a wheelbarrow vs. the same volume of micron particles taking the space of a massive dump truck.
10-75 Micron Particles
95%
(by volume)

15. Basic Filtration Options
“A Filtration System -no matter what kind it is, or how good it claims to be- can only remove the particles that have a chance to pass through it.”
Full Flow – Filtering 100% of the system flow
Side Stream Flow – Filtering a percentage of system flow (typically 10%-25%)
Basin Cleaning – Filtering between 10% and 20% of system flow and utilizing nozzles installed in the cooling tower basin to “sweep” solids to filtration system
Explain the Quotation at top of slide: For example, you can side stream 10% of the condenser water flow through a filter, however you are allowing 90% of the DIRTY condenser water to contaminate and foul your heat transfer equipment. This is why customers punch or clean chiller tubes once a year. They have a filtration system however they are not receiving the full benefit and or energy savings to be realized. With a basin sweeping system we are always providing clean water to the condenser and therefore realize the true benefits of having clean water. Energy is not wasted and tube cleanings can be extended to every 4-5 years. Now this is a good return on investment!!!!!

16. Full Flow Filtration Benefits:
Full 100% protection downstream with zero downtime
Maintain design efficiencies on all equipment
Ease of sizing & installation
More common in plan & spec jobs

17. Side Stream Filtration
Benefits:
Offers partial protection
Ease of sizing & installation
Applicable on large and variable flow rates

18. Closed Loop Filtration
Benefits:
5-10% is effective
Maintains a clean system
Zero liquid loss

19. Basin Cleaning Filtration
Benefits:
Attacks problem at the source
Comparable to full-flow filtration
Keeps basins clean
Reduced health & maintenance risks
Big energy savings potential
Here we are showing how basin sweeping is integrated with the LAKOS separator package. The drawing on the right shows the placement of the basin sweeping package with respect to the system – pulling water from, and returning the filtered water to the cold water basin of the cooling tower. The photo in the upper left shows how the filtered water is returned to the basin and used to “sweep” the dirt towards the filtration package inlet thus keeping the solids from ever entering the cooling system. It is important to note that the LAKOS design sweeps the water away from the condenser water pump suction. This approach was developed as a result of research conducted by LAKOS that showed 95% improvement in getting the dirt to the filtration packages as compared with traditional sweeper systems that swept the dirt towards the condenser water pump suction. Requires flooded suction.

20. Manual Basin Cleaning At least once a year Requires tower shutdown
Confined space regulations
Labor intensive
Can expose workers to safety/health hazards
Most customers clean the inside of their basin every year or sometimes even twice a year. With the proper basin sweeping system, your employees are not subjected to these confined spaces where they might slip, fall, or come in contact harmful bacteria such as Legionella.
OSHA is constantly redefining its definition of a confined space environment. Heavy fines can only be overshadowed by the liabilities in subjecting employees to these environments.
Also, if you are interested in Legionella control, you must employ basin sweeping

21. Basin Sweeping Required submergence: at least 2” (50mm)
Move solids to the filter
Continuous Cleaning
20psi (1.4bar) to nozzle header
Required submergence: at least 2” (50mm)
1GPM per ft2 of basin (2.5 m3/h per m2)

22. Cooling Tower Basin Sweeping Animation

23. Cooling Tower Basin Sweeping Animation

24. CT/Condenser Basin Sweepers
Articulated nozzles
Pipe clamps
Extensions cover dead spots
Factory installed or aftermarket
Click on the word “Sweepers” in the title to view the HydroBooster basin cleaning video
LAKOS HydroBoosters are a unique nozzle design that uses a venturi effect to increase the incoming flow by a multiple of 6 times. With a typical 10 gpm HydroBooster, you actually have 60 gallons of activity at the discharge of the nozzle to direct solids to the filtration package pump. (Note: if you have an actual HydroBooster “sample”, this is a good time to pass it around.)
Here you can see that we have two different types of HydroBoosters. In the top left picture you see a HydroBooster attached to a clip for easy installation. This HydroBooster is also adjustable while in operation. Other HydroBoosters may also be installed with a threaded connection as seen above. HydroBooster clips available in 2” only. Consult your LAKOS representative or the factory for specific basin layout designs.

25. Centrifugal Separators
Filtration Equipment
Centrifugal Separators
Removal of 40+ micron solids
Small to large flow range
No moving parts, little or no maintenance
Small to medium footprint
Low volume of water required for purge
Zero liquid loss options available
eHTX
Separator
LAKOS removes 98% down to 40 micron in a recirculating system, but LAKOS also removes a large portion of particles below 40 micron
eTCX
System

26. Filtration Equipment Sand Media Filters
Barrier filtration for water clarity, down to 0.5 micron
Small to medium flow range
More moving parts
Sand bed maintenance yearly
Medium to large footprint
Medium to large volume of water required for backwash (purge)

27. Bags / Cartridge Filters
Filtration Equipment
Bags / Cartridge Filters
Barrier filtration for water clarity, down to sub-micron levels
Small to medium flow range
No moving parts
Small to medium - Large footprint
No water required for purging
Maintenance required for removal/replacement bags or cartridges

28. Filtration Benefits
Energy savings due to increased thermal efficiency downstream
Water savings thanks to less frequent purge
Reduced health risks associated with solids build up
Extended equipment life cycle
Reduced maintenance, shutdown

29. Absolute Perfection vs. Affordable Protection
How Clean is Clean?
“Some level of Filtration is better than No Filtration”
Absolute Perfection vs. Affordable Protection

30. Think of the oil filter on your car...
Why is Filtration in HVAC Necessary?
Think of the oil filter on your car...
Wouldn’t you want filtration on your multi-million $$ HVAC System, too?
Think about the oil filter on your car... The oil filter takes out the particulates that could damage your engine components, and helps keep you engine operating at peak efficiency. Now think about the particulates in the cooling water of your HVAC system… Why wouldn’t you want to put filtration on your multi-million dollar system to keep it operating at it’s peak efficiency?
There are filtration techniques out there capable of incredible performance characteristics. Remember what you are attempting to accomplish. You can attain “absolute perfection”, but it will come at a considerable cost. Instead, consider the value of “affordable protection”, which satisfies your need to solve a problem at a cost you can justify and afford.

31. Basin Cleaning – Cooling Tower/Condenser
400gpm filtration package on (2) Cell
BAC condenser, courtesy Gallo Modesto

32. Review- Key Learning Objectives
Three Things You Should Remember:
Particle volume is more important than particle count
1 GPM per sq/ft for basin sweeping
40um is the smallest particle the human eye can see

33. Questions?

34. Thank You