Did You Know

Scale formation, biological growth, corrowsion and other sediments found insde air-condition condenser tubes have always been a problem for maintennce enginerers. 
These elements, if not controlled and/or not eliminatedd altogether , will cause many implications to the air conditioning system in a building. Thus, often cleaning of condenser tubes internal surface is required. 

The ATCS will continually keep the tubes clean throughout the year. Through this system, sediments will have no chance to settle and harden over time. When the internal tube surfaces of the condenser are clean, they will result in better heat transfer. With better heat transfer, the chiller system will achieve higher efficiencey, thus saving the building owner thousands of dollars in energy costs.

Through research and development (R&D) over the years, the ATCS has improved its cleaning system to using a Booster Pump. (depicted in the picture). The Booster Pump help to inject all the natural rubber balls into the condenser water supply (CWS) inlet pipe. There is no drainage of treated cooling tower water. This innovated system works at a low and high CWS pressure. 

OPERATION SEQUENCE (see installation concept drawing):

When the countdown time is out, a signel will be sent to the Diaphragm Valves (2a) and (2c) to open for a pre-set time amd Electric Valve (5a) to ATCS system #01 opens as well. The Booster Pump will also start to run. CWS is pumped, passing through (2a) , the Booster Pump and the through (2c) ad ito the the Ball Collecter (yellow, 3a), hece pushing all the rubber balls out int the CWS pipe line. The rubber balls are carried into the condenser unit and clean the sediments off the tubes. At a pre-set time, the Diaphragm Valve (2b) and (2d) will open, and the Booster Pump starts to run again. At this stage, it pumps the condenser water to the CWS pipe line, and at the same time returns all the rubber balls to the Ball Collector. A cleaning cycle is thus completed. This sequene will then move to the next unit at a pre-set time. 

This sequence will be repeated until all ATCS units are completed and the PLC will go into countdown mode again.

The ATCS Boost Pump Systme works perfectly wih low pressure (as low as 1.0 Barg) and high pressure (up to 20.0 Barg) condenser pressure applications.   

The condenser is an important part of the chiller. The operating condition of the condenser is the key factor that affects the efficiency of the unit. Formation of scaling and other foreign matters inside the cooling tubes will seriously deteriorate its performance, thus increasing power consumption. 

Reference to the Condenser Fouling and Energy Consumption Chart above (taken from Carrier Handbook), it shows that with and approximate 0.6mm scale thickness, an increase of 170% in heat transfer area is needed. In addition, with same scale thickness, the Fouling Thermal Resistance is approximately 0.002. It relates to 22% more horsepower per ton needed to obtain optimum performance. 

The Automatic Tube Brushing (ATB) System by Water Technology cleans chiller condensers and other shell and tube heat exchangers automatically without shutting down the equipment. This permanently installed system virtually eliminates tube fouling by removing debris from tube surfaces many times each day. 

The ATB system 4-way voalve reverses the condenser water flow for about 30seconds every 6 hours. 

ATB system brushes and baskets, the key to a strong system payback, installed in a condenser tube sheet. 

The four-way valve automatically reverses water flow in the condenser for about thirty seconds, once every six hours. The valve fits into the condenser supply and return piping and is custom manufactured to suit any piping configuration.

Nylon-bristled brushes are propelled through the tubes with the reversed water flow. Working in conjunction with good chemical treatment, the brushes clean the tube walls to eliminate scale formation and fouling. Each brush is designed to have a 0.025-inch interference fit in the tube wall.

Open-ended low-pressure drop catch baskets are installed in the tube ends at the tube sheet to capture the brushes in the condenser heads. Removable end-clips allow for eddy-current testing and brush replacement, which is normally recommended every four to five years. 

ATB system brushes and baskets, the key to a strong system payback, installed in a condenser tube sheet. 

The benefits include:

Energy Savings -  Lower fouling factors provide more efficient heat transfer. Electrical energy consumption is reducted by 10% to 30% when average fouling is eliminated. The ATB System is guaranteed to provide a 0.0001 fouling factor or better.

Maintenance Savings - The need to manually clean tubes is eliminated as the ATB system cleans condenser tubes daily. Labour and material costs for maintenance are greatly reduced.

Reduction of downtime - The ATB system eliminates the need to shut down heat transfer equipment throughout the year. In process industries, unscheduled downtime to manually clean tubes costs even more than the energy loss created by tube fouling. 

Reduction of chemicals -  Normal chemical treatment on tube walls can be redued as the ATB system keeps precipitation from forming on the walls. This prevention of precipitation also helps to eliminate periodic acid cleaning.