Where can I use a RABΞScreen BHA or BHC air intake filter screen?

RABΞScreens

RABΞScreen Protection stops debris before it costs you time, energy & money

Where can I use a RABΞScreen BHA or BHC air intake filter screen?

Anywhere that you have air movement. It does not matter what shape or size of opening we can design an air intake screen to suit every application. Dry air coolers, chillers, air handling units, condensers, cooling towers, intake louvres and air intakes of any design.

BHA – single layer of black, high abrasion polymer coated, polyester mesh. Black Pvc Coated High Abrasion Media is a 9x9 1000 Denier Multi Polymer Coated Polyester Mesh. The air flow resistance of a clean BHA air intake screen single layer is as follows:

0.50m/s               1.25pa
2.03m/s               8.75pa
3.05m/s               17.00pa

BHC – single layer black huckaback woven polypropylene. Black Polypropylene HoneyComb Weave is  a three Dimensional Polypropylene Honey Comb Weave which has a low air flow resistance whilst the electrostatic charge attracts  airborne debris. 

It can also be supplied in multiple layers of media to improve particle capture of 3 micron particles to 93%.  The air flow resistance of a clean BHC air intake screen single layer is as follows:

0.50m/s             1.25pa
2.03m/s             12.45pa
3.05m/s             22.42pa

Where would you use BHA or BHC?

The BHA air intake filters can only be used in a single layer  but it is a high abrasion filter and is perfect for the majority of applications where seed, pollen, leaves and insects are an issue. 

The BHC air intake screen is for use where fine particulate is a problem and a multiple layer filtration solution is required.  Ideal for fine cement, flour,  copier ink and other extra fine particulate.

Small investments, huge savings

The Health Estate Journal recently ran an article under the heading "Small investments, huge savings". 

It states that one of the key conclusions from the IHEEM Healthcare Estates 2014 conference was that basic energy efficiency measures could "shave millions of pounds from NHS estates' running costs", and that hospitals and other healthcare buildings face both "an air conditioning legal crisis", and a growing threat from outdoor air pollution.   

The whole article is very much worth a read, but one of the key statements is that there is plenty of "low hanging fruit" that any hospital can use to quickly, and cheaply improve energy efficiency. 

This last statement is so very true. 

Hospitals are a 24/7 operation and have a significant need for cooling which can be found at the heart of most HVAC systems.  

In a recent example we surveyed two separate cooling systems at the same facility comprising 1 x Alfa Laval Fin coil unit SCAG-8-5 and 4 x Carrier 09GHCA-178. 
 
The annual energy consumption for these cooling systems totalled 1,618,000 kWh which costs the trust just over £194K per annum to run. 

As you can see from the images below the horizontal coil faces were dirty with compacted dust, seed, pollen and other debris drawn into the fins. 

In a USA study by Pacific Gas and Electric they identified that 1mm of debris on a coil fin would cause a 21% drop in efficiency and increase energy consumption by as much as 30%.    

“When a condenser is dirty or unable to reject heat or energy, heat increases both the temperature and pressure of the refrigerant liquid line. The higher total energy, increases the flash gas that decreases system efficiency and capacity” http://www.refrigtech.com/Knowledge_Center/Knowledge_Characteristics_Evaporators.pdf  

That is why this forward thinking trust contacted RABSE distributor Advantiv to solve the problem of coil clogging and reduce the cost of running their plant. 

By installing an air intake filter screen to protect the coil faces, contamination will be significantly reduced as the cooling season progresses. 

The air intake screen is manufactured using a polyester core and polypropylene overlay which, during air movement, creates a static charge. This electrostatic charge easily captures the airborne particulate to PreVent® it getting through to the fins. 

No airflow, no electrostatic charge and this enables maintenance personnel to easily clean the air intake screens using a vacuum cleaner, hose or brush.  

By comparing with similar sites we would expect to see a minimum 10% reduction in running cost as the condenser is kept clean and efficiently rejects heat. 

The air intake filter screens were secured to the coil support steelwork using marine grade, nylon drop tab fastenings. In the event that access to the fins is required the screens can be easily removed and replaced.

With an air resistance of only 17 pascals at 3.05m3/s this highly effective external filter will continue to protect the coils for at least 10 years and produce an ROI of less than 12 months. 

That leaves the trust with savings of at least £175K over the next 9 years and why we are proud to be saving money for the NHS.

Richard Betts

Managing Director – RAB Specialist Engineers Limited

www.airintakescreen.co.uk

01635 248633

richard@rabse.com

Another way to use an air intake filter screen

In the world of air intake screens there always seems to be another application you have never thought of before. 

Many companies already recognise the benefit of fitting an external filter to any piece of air movement equipment was it provides an additional protection layer for valuable plant.

That is why we have installed to dry air coolers, vertical and horizontal chillers, air compressors, refrigeration display cabinets, cooling towers, building main intake louvres and AHU air intakes as well as a host of other cooling  and air movement machinery.

In a recent survey of a paper factory we were expecting to find paper fines and the normal dust, seed and other airborne pollutants causing problems. 

However, the writer was asked to survey the inside of this paper processing plant and found that they had a big problem caused by the shreds generated on the production line.

Like most modern and highly automated factories this site had miles of conveyor systems all controlled by sophisticated electrical equipment mounted inside mild steel cabinets.

The control boards, switches and plc’s all generate heat and to maximise the space each cabinet was also fitted with its own air conditioner.

These integral AC units (see http://seifertsystems.com/us/engineering/ for an example) draw ambient air into the enclosure which is then cooled, circulated and discharged back into the factory.

This fan driven air supply also draws in the paper fines, which are then deposited inside the enclosure and clog up the evaporator coil.

Obviously clogged fins are something that we have discussed regularly (see http://www.airintakescreen.co.uk/cooling-coil-filters1 ) but paper dust and fines laying on electrical components is another risk we had never considered before. Maintenance requires regular shut down and cleaning in order to minimise the risk of fire.

That is why the electrical engineer was so excited when he saw the patented Permatron R1 Magnetic Filter which could be placed on the intake without drilling the cabinet. 

Acting as an external filter the BHC Honeycomb Media attracts the dust and paper fines and will keep the enclosure clean avoiding both evaporator failure and minimising the risk of fire.

During a recent failure the replacement cost was over £2,000.00 and also shut down the production line. 

Yet it could have been avoided with a simple £65.00 high flow, low resistance filter which can be removed and cleaned before refitting.It may not be superhero stuff but we were pleased that another problem has been solved by an air intake filter screen from RAB Specialist Engineers.

Fresh air supply to London’s Heathrow Airport

Fresh air intake supply to London’s Heathrow Airport

London’s Heathrow Airport started out life as a small 150 acre plot purchased from the Vicar of Harmondsworth.

“Heathrow Before World War II Map”. Licensed under Creative Commons Attribution-Share Alike 2.5 via Wikimedia Commons –

It now employs 76,000 people within its boundary (equivalent to the population of Guildford) and is sat on 1,227 hectares.

That is 20 times its original size with five terminal buildings covering the land previously occupied by the hamlet of Heathrow, Heathrow House and various farms, orchards and market gardens. It is still defined by its 1950’s hexagram shape and now operates as one of the busiest airports in the world.
The terminal buildings cover 686,064m² and process more than 191,000 passengers on an average of 1,200 flights per day.
In a recent article written by Cordis the author states that up to 50% of the total energy in a typical airport will be spent on HVAC to maintain a suitable environment for passengers and staff.

CASCADE: REDUCING ENERGY USE BY AIRPORTS
Airports are big energy consumers – and that’s before a plane takes off or lands. The daily electricity and thermal energy used by a large airport compares to that of a city of 100,000 people.
This article goes on to quote
“A pilot scheme has been undertaken by two Italian airports, Fiumicino in Rome and Malpensa in Milan, used by 55 million people a year.
The project engineers concentrated on the large air conditioning units, chiller plants and cooling towers at the airports. They found equipment running when it was not needed, incorrect heating and cooling settings, poor positioning of sensors and poor maintenance”.

Heathrow Airport consumes a massive 701GWh per annum which is almost 4 x the annual production of the Glendoe Hydro Scheme. However, HAL do generate a lot of their own energy through various renewable schemes and are continuing to advance that technology in the new Terminal 2.

Terminal 5 is the largest free-standing structure in the UK and the roof area is the size of five football pitches.  It requires a massive 2,500,000m³/hr of air to serve its energy-efficient displacement air-conditioning system.

The air is filtered through three 11m² banks which contain a total of 726 filters.

Even at a highly efficient 15 watts per m³ that will be costing over £4,000.00 per hour or £30 million per year (figures are an estimate only) for this air supply only.

That is why efficient air movement is so critical because face loading on filtration systems will increase the energy demand exponentially.

Although the airport itself contains almost no flora and fauna it is surrounded by open spaces and gardens which create the leaf, seed and pollen debris that is blown across its 1,227 hectares. Add to that tyre rubber from 1,200 flights per day, dust kicked up from the runways and local roads and you can see that the filters have a hard job to do.

New Permatron PreVent® air intake screens are to be installed to protect the existing filter bank and the coil fins on the frontline frost coil.

The added benefit (currently under test) is that the changeover periods for the existing filter bank will be extended by a new washable filter with only a minimal effect on airflow.
Notes:

• CORDIS is the Community Research and Development Information Service
• Click here for the full article by CORDIS
• For more information regarding air intake screens go to www.airintakescreen.co.uk
• Richard Betts is the Managing Director of RAB Specialist Engineers who are the sole UK and European distributor of Permatron Air Intake Filter Screens.