Aquafan Vs Conventional Cooling Towers: Energy Comparison Calculation Model Explained


In order to compare the energy advantage of AQUAFAN with conventional cooling towers (WCN), we have to take a look at these systems in practical operational conditions. Installation are required to deliver design conditions for maximum performance which rarely occurs in practical situations for HVAC (coinciding of Maximum Wet Bulb Temp and Maximum Heat Load).

WCN cooling tower

Basing on the average WBT over the year as published by ASHRAE and assuming a heat load averaging 80%, we will compare the practical operations of AQUAFAN and conventional cooling towers. At design conditions, AQUAFAN consumes energy close to that of a comparable conventional cooling tower. The cooling tower is only one item in a cooling water system. The cooling water pumps and fans take care of water and air circulation and, by doing so, consume energy. A cooling tower is designed to give maximum ambient temperature (WBT or wet bulb temperature). However, this wet bulb temperature is not reached for a great part of the year.

The table shows the energy comparison for the total system of pump and fan energy in conventional. The consumption at 100, 80 and 60% heat load against the average WBT is projected for the AQUAFAN operating in combination with a VFD-equipped pump and a conventional WCD cooling tower equipped with VFD at the fan motor.Using 80% heat load as a fair and safe estimation of the real situation, the calculation model demonstrates considerable energy savings of AQUAFAN.

In situations where the cooling demand is around 75% of the design conditions, AQUAFAN cooling towers use 50% less energy compared to conventional cooling towers. During practical operations, the VFD-equipped AQUAFAN start saving energy by adjusting the amount of cooling water to the variable conditions. When the cooling water coming out of the condenser is below set temperature, the water flow will be reduced resulting in reduced fan speed as well. Savings are exponentially increased with decreasing cooling demands as pump energy consumptions are a cubic law of the pump volume.

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Save Energy And Money Through Enhanced Performance Of Chiller Condensers With Eqobrush


Fouled chillers can consume up to 30% more electricity per RT (refrigeration ton) of cooling then clean ones. Keeping the installation in pristine condition is therefore paramount in good building management that aims at cost-cutting and carbon footprint reduction.

Eqobrush is an automatic online cleaning system for chiller condensers. It cleans fouling from system tubes without the need to shutdown the equipment. Manual heat exchanger cleaning will be a costly nuisance from the past.

One of the most serious problems in building management is the formation of deposits and other contamination in water-cooled chiller condensers. Eqobrush automatic tube cleaning system for chiller condensers, is designed to address these problems during the normal process of operation. Any fouling or scaling in the tubes can be avoided with a series of brushing cycles per day. This will result in energy savings and capacity gains allowing a pay-back period of less than one year.

The system is consists of two catch baskets and one brush for each heat exchanger tube. Both baskets are fitted permanently to the pipe ends and serve to receive the brushes. Each tube is brushed in two directions at pre-programmable intervals without interrupting the process of operation. The microscopic contaminants will be eradicated from the system through the regular water blow-down from the cooling tower.

Eqobrush’s reversal v/alve can be easily installed on the supply and return pipes. It periodically reverses the flow through the condenser for a short time.Also, the system can be designed to be incorporated in the original plant room installation or for retrofitting. The need for chemical or physical cleaning and chiller shutdown is minimised drastically allowing for utmost operational efficiency.

Principles of Operation

  • The automatic valve of the system reverses the water flow in the heat exchanger every 4 hours for 30 seconds.
  • Its nylon brushes, which are housed in baskets connected to the tube ends, are then pushed through the pipes, cleaning any fouling and scaling.
  • After the reversion, the brushes are nestled back in their baskets, where they do not cause any pressure loss.

Benefits of Eqobrush

Eqobrush Automatic Tube Cleaning System

Energy saving.

Condenser efficiency is affected by collective fouling and scaling. When the level of contamination increases, less heat is removed from the condenser causing it to have to operate at a higher temperature. Initially, this causes higher electricity consumption to perform the cooling job. Eventually, it will cause the chiller to trip and the cooling system to fail.

Reduced maintenance cost and machine downtime.

Periodical maintenance of chillers is eliminated by the Eqobrush system which means areduction in:

  • Cost of labour,
  • Cost of chemicals.
  • Cost of cleaning requirement.
  • Human exposure to corrosive chemicals.

Reduced water consumption.

Eqobrush allows a higher level of salt concentration in the cooling tower which will result in the following:

  • Reduction of blow-down volumes.
  • Reduction of suppletion water volumes.

Capacity

Optimum cooling performance ensuring the equipment can run at top capacity.

 

Eqobrush by Watco Group For Shell and Tube Heat Exchanger & Condensers


The Eqobrush Automatic Tube Cleaning System for shell and tube heat exchanger and condensers keep the heat exchanger tubes free from fouling and scaling without interrupting operations. This allows optimized heat exchanger designs for top-performance at minimal energy cost. Manual heat exchanger cleaning will surely be a costly nuisance from the past.

Heat exchangers and chiller condensers suffer from fouling and scaling which is an inevitable problem when used in combination with open cooling towers. This will result in massive damages in capacity loss, energy consumption, maintenance, heat exchanger cleaning and equipment life span. About 50% of heat transfer resistance is attributed to fouling causing an additional maintenance budget of up to 8%, more than 10% of electricity cost of HVAC systems and around 0.2% of the Gross National Product or GND of industrialized countries like the United States.

The traditional way of dealing with fouling problems is through scheduled maintenance wherein installations are either mechanically or chemically cleaned which interrupts the operation. Numerous factors such as standstill, manpower, equipment, production loss and use of chemicals adds up to the whole fouling-related cost because of this.

Operational principle of Eqobrush

Eqobrush’features an electrically powered flow-reversal valve which can be simply installed on the supply and return pipes. These valves periodically (every 4 hours) reverse the water flow through heat exchanger for about 30 seconds without disturbing the flow to the cooling tower. The flow will return to its normal direction in less than a minute without any impact on the heat exchanger process during this momentary interval.

Nylon brushes are installed in PE catch baskets on both ends of each tube inside the heat exchanger. During the flow reversal cycle these brushes travel up and down the tubes propelled by the water flow and cleaning the heat exchanger by eradicating deposited matters from the tube thus preventing any crystallization and buildup. All the matters removed will eventually settle in the basin of the cooling tower.

The components of Eqobrush are designed to generate minimal additional pressure loss by either the brushes and baskets or the reversing valves.

Advantages of using Eqobrush

Preventing buildup of fouling in the heat exchanger has several advantages, they are:

  • Reduce overall fouling related cost.
  • Electric energy consumption in chiller condensers.
  • Fossile energy consumption in industrial heat exchangers due to efficient heat transfer.
  • Energy consumption in system pumps.
  • Minimization of scheduled and unscheduled down-times.
  • Save water in cooling tower.
  • Save chemicals onmanual cleaning.
  • Equipment life time extension.
  • Reduction of capex for new projects.

Note: the reversal valves can also be used to automatically backwash plate and frame heat exchangers. During operation silt, sand, mud and other fine particles enter the plate heat exchangers and accumulate between these plates which then cause it to plug and promotes scaling and pitting. Periodic backwashing by means of a flow reversal valve removes any accrued solids and allows significantly longer intervals between interruptions of operation for heat exchanger cleaning.

About the Author:

Hubert Poels is one of the share-holders and Managing Director of Watco Group. His passion and commitment to help the environment and serve society is reflected in the innovative water cooling technologies the company offers. When he is not busy with his social responsibilities, he likes to research about remarkable contents while having a cup of his favourite coffee. He is renowned in the industry because of his dedication and extensive experience.

High Performing Cooling Tower Systems


Every industrial water cooling tower systems from Wacon are extensively researched developed and tested. With the use of state of the art technology in their design, they have come up with top performing water cooling tower systems that are steadfast and cost-effective components. This resulted in an excellent range of water cooling systems that are very dependent.

WCN – Induced Draft Modular Counter Flow Cooling Towers

 The WCN Cooling Towers are designed in accordance with the international industrial standards and passed a field performance test in accordance with the CTI STD 105 or DIN 1947 field test protocol.. They are lightweight but extremely rigid. Installing the WCN is easy, quick and simple as it uses structural materials like SST 304 and FRP pultrusions with PVC or ABS fills and eliminators.

WRT Cross Flow Cooling Towers

 The WRT Cooling Towers are also designed in accordance with the international industrial standards. Due to the infill of this cooling tower system having a distinguishing pattern, the tower hold-up time is longer resulting in a longer contact period for heat exchange with the air. These cooling tower systems are also lightweight and very rigid structures made with structural materials such as SST 304 and FRP protrusions, with PVC or ABS fills and eliminators. In addition, they passed a field performance test in accordance with the CTI STD 105 or DIN 1947 field test protocol and are simple to install and easy maintain.

CentraDeck – A revolutionary Cooling Tower Drift Eliminator with great efficiency 

This CentraDeck cooling tower system drift eliminator is manufactured from PVC, PP or ABS thermoformed film and can be used for numerous operational applications. It features a triple angle labyrinth design which effectively strips the wet air-stream from water in the form of droplet.

Centrafill – A revolutionary Cooling Tower Fill Splash & Film Heat Exchange Medium with great efficiency

 The Centrafill Cooling Tower System is created from predetermined layers of triangle corrugated profiles which come in cross section in the direction of one another in the tower structure. Due to the positioning of the corrugated profiles, the air is powerfully turbulated in the infill structure. Also, a high low-pressure drop and energy consumption can be achieved due to the structure of the cooling tower system being an open one.

CentraPack – An efficient Cooling Tower Film Heat Exchange Medium For clean and treated Cooling Tower Water

 This efficient CentraPack cooling tower system on the other hand is made up of predetermined layers of vacuum formed corrugated sheets with a snap-on- positioning system.Each sheet is in opposite mirror locations, therefore, creating a labyrinth function for the water and air contact. The open structure of the cooling tower system provides low pressure as well as energy consumption drop.

The Cooling Tower Structures Include the Following Items

  • Stainless Steel Parts
  • FRP pultrusions
  • FRP Panels
  • Fan Stack
  • Fan Deck
  • Water Basin
  • Handrail Ladder

Eqobrush: Heat Exchanger Fouling and Cleaning Solutions


Heat exchanger fouling and scaling is a problem that has an impact on both the environment and economy. There are several types of fouling that can be distinguished depending on industrial application, environment, and water quality.

In recent years, there has been a dramatic rise on the collective awareness on the issue of reducing environmental pollution. International treaties regarding this problem have focused on some industry sectors who are found to be notorious polluters.

The need to provide a solution to the critical and frequent problem in the production is what drives the decision-making process of these industries on fouling.

What is Eqobrush and how does it work?

Eqobrush- Automatic Tube Cleaning System ensures that the tubes of your heat exchanger or condenser are kept pristine during normal operation of your systems. It prevents the formation of fouling and scaling by high-frequency automatic tube brushing of heat exchanger or condenser tubes at least 6 times per day.

Powered by the water flow through a flow reversing valve, the brushes which are inserted in the heat exchanger will travel up and down the tube. The Eqobrush-Automatic Tube Cleaning System will remove any sedimentation before it toughens. This keeps the tubes in top condition to achieve top performance at all times without disruptions of operations for mechanical or chemical cleaning.

In addition, fouling and scaling in cooling systems are found to have a massive impact in capacity loss, energy consumption, maintenance, cleaning and equipment longevity. With Eqobrush, it is common to make a payback period on the investment in less than a year, therefore allowing considerable savings.

Advantages of using Eqobrush

The prevention of build-up of fouling in the heat exchanger has a number of advantages.

  • Reduce overall fouling related cost
  • Electric energy consumption in chiller condensers
  • Fossile energy consumption in industrial Heat Exchangers due to Efficient heat transfer
  • Energy consumption in system pumps
  • Minimization of scheduled and unscheduled downtimes
  • Save water in Cooling Tower
  • Save Chemicals On Manual Cleaning
  • Equipment lifetime extension
  • Reduction of Capex for new projects

 

Eqobrush is more than a contributor in the profitability of operation; it also helps in conserving the planet for future generations.

Aquafan Vs Conventional- Energy Comparison Calculation!


It is always necessary to look into the system operational conditions in order to compare the energy advantage of the systems. However, when it comes to the comparison of Aquafan with conventional cooling towers, then practical observation is a must. The design conditions should be at maximum performance required by the installations to deliver. When practically working, in HVAC system coinciding of maximum wet bulb temp and maximum heat load will rarely occur.

For over a year, we base ourselves on the average WBT to compare practical operations, where we assume an average heat load of 80%. At design conditions, the energy consumption of Aquafan is nearly close to a conventional cooling tower. The minimal losses occur during the transfer of energy from water to the turbine is remunerated by the way that water weight required for legitimate distribution in conventional (around 0.5 bar) is utilized to pivot the turbine of Aquafan.

While practical operations, the Aquafan equipped with VFD adjusts the amount of cooling water to variable conditions to save a sufficient amount of energy. When the cooling water is coming out of the condenser is below the adjusted temperature, the flow will be reduced. Due to the reduced pressure and water flow, the speed of the fan will be reduced automatically. Pump energy consumptions are directly proportional to the cubic law of the pump volume, therefore with the decreasing cooling needs, the savings increase effectively.

The consumption rate at 100, 80, 60% against the average WBT is projected for the Aquafan and conventional WCN cooling tower. Here, the energy comparison is the sum of the total system of pump and fan energy. Using 80% heat load as a fair and safe estimation of the current situation, the calculation process signifies the sufficient amount of energy savings of Aquafan.

Ways To Keep Your Heat Exchanger Tubes Clean!


Getting down with this article, you will come to know the best and effective ways of how to keep your heat exchanger tubes clean easily. Cleanliness of the heat exchanger tubes is really very important to enhance their working efficiency and maintaining the required temperature in your system or process.

The lower efficiency of the heat exchanger is caused due to fouling and scaling that accumulates in the tubes and the development of algae on the pipe walls. Furthermore, this also decreases the flow of water in the cooling system as fouled tubes have a higher pressure drop. Because of this, the heat exchangers get clogged and stop performing.

Therefore, for the proper functioning of the system, it is essential to avoid the scaling of residues. Still, if the concept is not understood, then imagine yourself not brushing the teeth for 3 days. How it feels and how much time it will take to the dentist for cleaning the scaling. So, for the long term and reliable functioning of the systems, ongoing cleaning plays a vital role. There are two different ways for cleaning the heat exchangers in a manner that promotes the performance of the system.

Manual Cleaning Route– This method includes the opening of the heat exchanger, possibly removing the tube bundle from and cleaning it manually. Chemicals and brushes are being utilized to dissolve and remove the residue. Even, the high-pressure cleaning is also used for clearing out the hard residue accumulated hardly on the walls. The drawback to this method is that you need to do this one regular basis (interruption of operation) and that the effectiveness of the equipment gradually reduces between the cleanings.

Automatic Cleaning Route– To avoid scaling to take place insert brushes in the tubes (logged in catch baskets at the end of each tube). A reversing valve manages the up and down movement of the brushes at regular intervals that control a constant cleaning process. This is achieved by simply reversing water flow over the heat exchanger for a short interval during which the water flow propels the brushes through the tubes, removing all the dirt and sending it to the cooling tower basin. Eqobrush, the best automatic brushing system is designed to perform the same. With this consistent and constant cleaning, debris does not have sufficient time to collect and set. This implies your heat exchangers remain at ideal execution constantly.

This automatic brushing system by Eqobrush offers numerous advantages over the manual cleaning process while reducing the maintenance cost and providing ecological benefits to the companies for the efficient performance of their processes and systems.


EQOBRUSH keeps shell & tube heat exchangers clean from fouling during operation. It achieves serious energy savings, production upgrades as well severe reduction of maintenance cost. It also minimizes the risk of unscheduled down-time as well reduces the use of chemicals for water treatment.

EQOBRUSH is a system that can be easily retrofitted to any existing heat exchanger or chiller. Precondition is that the tubes are clean at the time if installation.  Component standards as mentioned below. We can engineer the components tailored to your specific requirements.

Brushes: PE with Stainless steel wire and nylon bristles.

Catch baskets: PE baskets, easily removable from the socket when necessary. Locked in operation to secure all baskets at the tube ends.

Reversing valve: Steel & Stainless Steel valves up from PN6 up to PN 25pressure levels.

Actuator: Compact multi-functional actuator with end position switches and torque control in IP55 housing with. Manual emergency operation possible.

Control box: Standalone control box with timer functions, cycle counter and visual indication. Enclosure IP 55. Alternative PLC controlled function connectable to any BMS.

System Options wit PLC:

  • Interface for communication with Building or Process Management System
  • Remote monitoring of cleaning cycles and chiller energy consumption

EQOBRUSH - System Components

Cleaning of Heat Exchangers


Heat exchangers are critical components of your system and are in regular need of cleaning. The constant need for process cooling is provided by the water circulating over heat exchanger tubes and cooling tower. Because the heat exchanger performance is paramount to keep your system running at required capacity it is crucial to keep the tubes in optimal shape at all times.

Fouled heat exchangers reduce the efficiency of your operation, with possible safety issues down the road. Also, consider the financial damage caused by fouled heat exchangers, as fouling is documented to cause for 8% of industries maintenance budget

Why tube cleaning?

Evaporative cooling is the most efficient method of process cooling. Water is the critical component in this to avoid the build-up of heat in you process.Water management is inevitable to keep the system from accumulating residue, fouling, scaling etc. Even with optimal water quality management regular cleanings should be scheduled to prevent heat exchangers from clogging up unless alternative methods are applied.

The deposit mostly consists of algae, which forms a slimy layer and cannot be avoided by various chemical cleaning processes. This layer, with the addition of calcium and magnesium starts solidifying and creating a hard layer of residue that is very hard to clean. This is why chemical cleaning is not that efficient.

Cleaning interruptions – not as effective as you’d hope

Chemical Cleaning

Without physically cleaning all of the micro particles and build up, it’s impossible to expect a pristine clean system. Excellent chemical water treatment can help and reduce the rates of accumulation, but not remove the threat altogether.

On top of that, chemical cleaning makes you stop the whole process, until the residue is removed to an acceptable level (no complete removal can be achieved). In addition, the typical chemical cleaning uses chemicals that are harmful to the environment, and require to be done routinely.

Mechanical cleaning

In contrary to chemical cleaning, mechanical cleaning can remove all the fouling from the pipes and can therefore be done at longer intervals than chemical cleaning. The cost of mechanical cleaning however are substantially higher than chemical cleaning.
Depending on the maintenance turnaround schedule of the process facility a choice between chemical and mechanical cleaning will be made.

EqoBrush system
A Cost effective and Eco Friendly way toclean the heat exchanger tubes

There are other ways to clean your heat exchangers. The usual ways of cleaning involve maintenance-labor, chemicals, and stand still costs. However, there are systems that allow the tubes to clean themselves, continuously and with no chemicals involved. Also we need to keep in mind that heat exchanger designs can be based on non-fouling which may reduce the heat exchange surface with around 20%.

The EqoBrush system is such an on-line cleaning system. It is designed with both cost-saving and the environment in mind and offers long term value. The EqoBrush Automatic brushing system performs brushing of all the tubes in the heat exchanger every 4 hours, 24 hours a day and 365 days a year. The brushes in the tubes do the work of cleaning the system for you, all of the time. This means that the heat exchangers no longer dictate your turn around moments and perform always as new.

Find out more about EqoBrush on our website at www.eqobrush.co

Reduce Total Fouling Related Cost With Eqobrush in Processing Industry


EQOBRUSH impact on Total Fouling Related Costin the Chemical- and Petrochemical Industries.

For over 50 years Automatic Brush Cleaning systems are popular in process heat exchangers as a tool to keep the tube walls in top-condition.

Any normal heat exchanger will foul during operation. Fouling reduces efficiency and calls for cleaning sessions with interruption of operations. Between sessions the heat-exchange efficiency is progressively reduced up to the level where the heat exchanger becomes bottle-neck for production capacity of the operation.

Unexpected shut down due to uncontrolled fouling is a substantial threat to the process industry with high expenses involved.

Total Fouling Related Cost (TFRC) in processing industry is difficult to assess. Literature reports the TFRC at 8% of the total maintenance budgets and in addition up to 5% of energy consumed is used to overcome fouling.

TFRC cost consists of the following components:

• Cost of cleaning (mechanically of chemically)
• Cost of production standstill during cleaning
• Cost of efficiency loss between cleaning intervals
• Cost of unscheduled interruptions

To minimize TFRC while maintaining maximal production output with controlled operations the best approach is:

• Keep heat exchangers’ tubes clean at all times
• No cleaning intervals are required
• No efficiency or capacity loss throughout operations

With EQOBRUSH installed TFRC can be kept close to zero while the heat exchanger tubes will remain clean 365 days a year with no surprising factors ahead.

Additional operational advantages:

• Reduced water consumption in the cooling tower is an additional advantage (higher allowable Cycle of Concentration in cooling tower water).
• Energy savings in (steam) condenser cooling via VFD controlled cooling tower fan.

EQOBRUSH impact on CAPEX

For new systems the impact on CAPEX (capital expenditure) should be considered as an additional important economic benefit of automatic tube cleaning.

OVER-DESIGN

Heat exchanger design engineers are aware of the constant fouling build-up in heat exchangers and the loss of heat exchange efficiency caused by this. For this reason, those heat exchangers are designed with excess heat-exchange surface of an average of about 30%. This has considerable impact of the CAPEX of this equipment and the related installation cost (footprint, foundation etc).

BACK-UP EQUIPMENT IN FAIL SAFE OPERATIONS

In fail safe operations where the risk exists that fouling in heat exchangers may cause sudden efficiency losses, back-up heat exchangers are required. The impact on the CAPEX of such operational system are substantial:

• Additional equipment cost
• Connections and control system

Eqobrush automatic tube brushing system guarantees the tubes to remain in top condition at all times via:

• High frequency tube brushing (6 or more cleanings per day) with
• Smart design tube inserts (no pressure drop)
• No additional energy requirement (using existing water pressure)

Appreciation via experience

Automatic Tube Brushing systems have been around for decades in Germany where it was originally invented. With this long experience and the need to reduce the industries’ environmental impact, a high percentage of the process heat exchangers in European chemical industry are equipped with automatic tube cleaning systems. The industry is convinced of Eqobrush’s huge benefits in CAPEX, Total Fouling Related Cost control and last but not least its positive effect on the environment.

Contact us to for a budget quote and assessment of the economic impact on your operation.

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