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Inside AKOTRACE® Electrical Heat Tracing System for CSP Plants

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Page 1: Free e-book about EHT
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INDEX

INTRODUCTION: Optimization is the key ............................................................. 3

A small but key investment for any CSP plant ..................................................... 4

Avoiding Poorly Performing CSP plants ................................................................ 5

CSP plants: When temperature regulation fails ................................................... 6

CSP Plants: Poor planning, poor performance ..................................................... 7

4+1 key factors to consider in an electrical heat tracing system ......................... 8

The structure of an optimal heat tracing solution (I) ........................................... 9

The structure of an optimal heat tracing solution (II) ........................................ 10

Optimal installation of the Electrical Heat Tracing System (I) ........................... 12

Optimal installation of the Electrical Heat Tracing System (II) .......................... 14

AKOTRACE® Solution for HTF areas .................................................................... 15

AKOTRACE® Solution for Molten Salt areas ....................................................... 16

PROTrace®: Control and power cabinets for electrical trace circuits (I) ............ 17

PROTrace®: Control and power cabinets for electrical trace circuits (II) ........... 18

PROTrace®: Control and power cabinets for electrical trace circuits (III) .......... 19

PROTrace®: Control and power cabinets for electrical trace circuits (IV) ......... 20

DUOControl Trace: The brain inside AKO´s ProTrace® cabinets (I) ................... 21

DUOControl Trace: The brain inside ProTrace® cabinets (II) ............................. 22

AKONet Trace, AKO´s control software for EHT systems ................................... 23

DUOVision Touch Trace: Designed for small EHT systems ................................ 24

AKO´s MI heating cable ...................................................................................... 25

Temperature Sensors I ....................................................................................... 26

Temperature Sensors II ...................................................................................... 27

AKONet Trace: Alarm Management (I) .............................................................. 28

AKONet Trace: Alarm Management (II) ............................................................. 29

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Optimization is the key

Optimizing the performance of a concentration solar power (CSP) plant is essential.

Weather a plant uses parabolic cylinder technology or a concentrating solar power tower, managing the process of transforming sun energy into electricity is

a tricky task. That´s when an optimum electrical heat-tracing system comes into place, especially in thermal storage plants. We know that there are other components that play an important role in any plant, but this particular one is crucial because its malfunction can lead to major problems with costly solutions.

The transformation of energy is possible thanks to the thermal transfer between

heat carrier fluids such as steam, thermal oils or molten salts.

At the end, is the thermal oil, in the case of parabolic cylinder´s plants, and

molten salts, in solar power tower plants, that by ex-changing heat generate the necessary steam to drive the turbine that makes electricity.

The main function of an electrical heat tracing system is to maintain the right temperature throughout the process, avoiding solidification of the fluids,

whether they are oils or salts.

If this crucial component fails, the plant could incur into unexpected expenses or, even worst, it can result in having the plant out of commission for a period of time.

Even with optimum planning, there are always some unforeseen problems that can arise during installation, execution and maintenance of any heat tracing system, and each one of them could have a different impact on the plant.

In following posts we´ll try to analyze some of the most common risks assessed in economic terms.

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A small but key investment for any CSP

plant An electrical heat tracing system represents just 0,5% of the total investment in a CSP project, but its failure could lead to major losses that could affect the overall profitability ratio of the plant. Therefore, optimizing the performance of the electrical heat tracing system is critical to be consid-ered as market leaders. There are, though, some factors that could compromise this goal. How?

Let´s first make a short list of economic indicators that can determine in any way the outcome of the expected net production of a solar plant:

Capital expenditure (CAPEX).

Days of production.

Production efficiency (a combination between performance and opera-tional /production costs).

And now let´s make a second list, this time of what happens when the electrical heat tracing system is not managed properly or fails unexpectedly:

It raises the plant´s expenses.

It can reduce the performance of the main electrical production systems.

The amount of self consumed electricity of the plant could raise unex-pectedly.

If the breakdown causes a plant stoppage, it would inevitable translate into less production days and major reparation costs.

All these factors are directly related to the first list: They all alter the initial plan in terms of money and time, and all of the sudden, this 0,5% becomes more crucial.

We have been talking economics, but in our next post we´ll take a look at the

technical challenges that a plant can face when the electrical heat tracing system does not perform as expected.

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Avoiding Poorly Performing CSP plants

The scenarios that could lead a CSP plant to perform poorly are diverse.

All the components of the plant can be in trouble at some point. There are mistakes of a more technical nature, but failures could also emerge from planning to execu-tion; from maintenance to supervision.

Undoubtedly, the electrical heat tracing system plays a key role in the overall perfor-mance of the plant. It goes across the power block (the Thermal Energy Storage, The Heat TransferFluid and the Balance of Plant systems) therefore, from a technical stand of point we are talking about a wide range of possible breakdowns.

Let´s enumerate some of them: (1) Unplanned stoppage when heat carrier fluids get frozen; (2) Loss of performance due to poor temperature regulation of the processes (HTF, TES, and BOP); (3) Unsuitable requirements (when the plant is already operational).

There is a saying that goes…”Your lack of planning is not my emergency¨. Well, unfortunately in CSP plants, lack of planning is everybody´s emergency. It represents another costly mistake that could prevent a CSP plant to perform optimally. Some other failures of that nature:

Unexpected investments and/or interventions when the plant is fully operational.

Being behind schedule without enough time to react (taking into account that the tracing system is one of the last components to be installed).

Lack of background knowledge to ensure the performance of the plant.

More investment costs (when the engineering part of the process hasn´t been planned properly).

Some of these failures could be managed, unexpected problems show up in any project, but some of them could be avoided. What we´ll try to analyze in

following posts is why CSP plants and their electrical heat tracing systems face these issues in the first place, and then come up with efficient solutions and alternatives.

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CSP plants:

When temperature regulation fails We continue analyzing ways of avoiding

poor performance in CSP plants and their electrical heat tracing systems, focusing today on breakdowns caused when temperature is not regulated properly.

One of the worst fears for anyone involved in a CSP project is having the plant out of commission, even for a short period of time. But unwanted plant stoppages do happen and bad temperature regulation can be one of the causes leading to this

undesirable outcome. Let´s take a look at what happens when either water or heat transfer fluids freeze. This scenario could present itself when:

The engineering team lacks thermodynamic expertise, that is, do not have enough experience in Thermal Cycles inside CSP plants, undersizing the whole project thus causing system failing.

When the system control solution is weak preventing the staff from receiv-ing valuable, real time information to help them detect and manage on a timely manner a wide range of possible system´s breakdowns

Faulty installation due to lacking of know-how to notice details that are key to the system and a deficient quality control supervision

Such shortcomings could cause the plant to be out of commission for one day

which translates into $267,000 in losses. There is more: The additional costs of

repairing the tracing system and/or damaged equipment could add up to $8.2 million.

Another issue that could arise regarding temperature supervision is when the

established system for process temperature regulation (HTC, TES, BOP) is not efficient, resulting in a significant loss of performance. This happens, among other factors already mentioned in the list above, when the implemented regulation solution is weak. This particular mistake could cause a 5% increase in energy self consumption of the electrical heat tracing (for each degree increase in temperature in the system´s performance).

On our next post, we will analyze what happens when the team in charge of a CSP plant does a poor job planning the project.

*Data referring to CSP plants using parabolic cylinder technology with a molten salt storage for up to 7, 5 hours.

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CSP Plants:

Poor planning, poor performance It´s only logical: if you don´t plan correctly, you don´t get the expected results. Breakdowns of a technical nature are, sometimes, unavoidable. Bad planning is a human error, and such kind of mistakes seem easier to solve, don´t they? Yes,

but let´s be honest, in a CSP project with budget and time concerns and limitations some of the simplest principles that we all know “in theory” are rapidly overlooked. All of the sudden solving this issue gets complicated.

A management team with no experience or that doesn´t handle properly a CSP project contributes to:

Applying an ineffective supervision and quality control solution for the plant

A poor execution of an already poor plan

If these problems originated because of time related pressures we have some bad news: It turns out that to solve them would take even more precious time. We are talking about delays in the starting of the plant, and since the electrical tracing system is one of the latest components of the plant to be installed, the team finds itself in a position with not enough leeway to react.

As in any other business, loss of time means loss of money. In this case we are talking about:

The plant could be out of commission for one day which translates into $267,000 in losses.

A 20% capital budget deviation, that is $410,000

As we stated at the beginning, poor planning is probably one of the most

complicated issues to handle when analyzing critical risks in an inadequate electrical heat tracing solution, but it is not impossible to solve. If you want to learn about how to deal directly with these and other challenges related to the

development of a CSP project, we invite you to get familiar with our Akotrace® solution.

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4+1 key factors to consider in an

electrical heat tracing system

In this blog we have already stated how critical an electrical heat tracing system is in the

temperature control process of any CSP plant.

We would like to go deeper into the issue and

share with you the 4+1 key factors we think should be taken into account when choosing or designing a heat tracing solution.

Energy Efficiency

This is particularly relevant since the less energy the plant self-consumes, the

more energy it has to sell, in other words: Managing energy efficiency improves plant´s productivity.

Connectivity: Control and Monitoring

To be able to detect a problem in a timely manner gives the plant´s staff the opportunity to react and fix any malfunction in the shortest period of time. On the other hand, it is nice to know that everything is working fine, have periodical reports to confirm it, and use this information to make further improvements.

Usability

The staff should be properly trained and the software intuitive enough to provide a fast response whenever a crisis arises, as well as to manage the day to day tasks without a glitch.

Safety and Reliability

Yes, the tracing system is no more than 0,5% of the total investment of any

plant, but if it does not work properly the loss of productivity, and of money, can be substantial. A safe and reliable solution makes everybody involved in the plant sleep better at night.

An optional one: Flexibility

This one is up to you, it depends more of your business model. In AKO we

believe that the success of our AKOTRACE® solution relies, in addition to the

above mentioned, on its flexibility to adapt to any project, and to any plant.

Whether it uses parabolic cylinder technology or concentrating solar tower, AKOTRACE® is designed to be flexible enough to suit every client´s needs. The projects may be different, but the outcome is always satisfactory.

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The structure of an optimal heat tracing

solution (I) After considering all factors involved in the decision making process when choosing an electrical heat tracing solution, it is time to describe how the

system works. In our case, we want to share with you the structure of our DCS AKOTRACE® solution, a framework that holds three levels of performance areas designed to fulfill the needs of any CSP plant.

Field and installation

From the base up, Level 3 is made up of all the heat cables and heaters, probes, accessories, lagging, and, in general, of any element necessary for the installla-tion of the tracing system.

Control and Power

Level 2 distributes the necessary power to the tracing system, regulating and controlling its delivery according to the information received (thermal probes and electrical supply; safety indicators, etc)

Supervision and Connectivity

Finally, Level 1 monitors and supervises the tracing system connecting it to both

the plant´s DCS system and to possible telemanagement points.

All three levels of our AKOTRACE® structure are supported by a layer of ser-vices that include maintenance (reactive, proactive and preventive), engineer-ing, project management, installation and implementation.

In our next post we´ll do a more detailed analysis of the role each one of the

levels play in the structure of our AKOTRACE® electrical heat tracing system.

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The structure of an optimal heat tracing

solution (II) The goal of any electrical heat tracing system is to maintain the temperature, avoiding the freezing of either water or heat transfer fluids.

How AKO does it? Let us explain in detail the three-level structure of our AKOTRACE® electrical heat tracing system.

Field and Installation (level 3)

It´s made up of all the elements in the system´s control and is where the elec-trical heat tracing circuit is placed. It includes all the necessary field compo-nents, and depending on the process needs each control can have:

Either standardized or custom made heating elements, depending on the tracing needs, including MI Cable, Self Regulating Cable, heaters and all accessories required for a full installation

Up until 4 thermal probes with different redundancy options, this guaran-tees data reliability.

Current probes that constantly monitor the system´s control energy self-consumption, warning of any drop below certain values, allowing us to identify possible failures in those cases when several tracing sections are integrated into the same system´s control

Control and Power (level 2)

In this level our PROTrace® cabi-nets are in charge of monitoring and distributing the power from the connection point to system´s control. They can have different mechanism of redundancy to avoid malfunction in case of failure or during maintenance. They are fully adaptable. Based on the applica-

tion, our PROTrace® cabinets can be concentrated in different locations or distributed throughout the field. Their final placement depends on the technical and economical needs of the project.

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Our system´s control is based on our DUOControl Trace, founded on a PLC Platform, and integrated into PROTrace® cabinets. It receives data from the thermal probes and power supply, protection conditions, configuration variables, etc, and it acts accordingly, regulating the output power to reach and maintain the desirable temperature, thanks to our advanced control algorithms.

Inside our PROTrace® cabinets there is the possibility to include the kind of control, via contactor or SSR; the air conditioning or distribution elements and the automatic transfer switch.

It also accommodates safety and protection elements such as magneto-thermal circuit breaker, differential circuit breakers protection and a contactor´s security system in each control, adding an extra safety component in case of switcher´s failure.

Supervision and Connectivity (level 1)

Our ProTrace® cabinets are stick to each other with optical fiber connec-tors. Their ring configuration allows for non-stop communication in case of malfunction in one of the links.

In this ring configuration we have

our DUOWarm Trace, supervising key variables such as power distribu-tion and the environment conditions in the cabinet. It also functions as a gate-way with the plant´s DCS system and with the firewall that allows the internet connection to manage the installation remotely. It has a redundancy system to avoid communication breakdowns and to facilitate maintenance work.

The local operator panel, made up of a PC Panel with our control software AKONet Trace, only needs an Ethernet link to the network control DUOControl Trace, allowing for the total control and supervision of the tracing installation.

We have just share with you the electrical heat tracing system that makes us worldwide leaders in the sector. We have installed this architecture solution in more than 25 plants, but we are constantly looking to innovate and find new ways to optimize our system and at the same time, the productivity of any CSP plant.

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Optimal installation of the Electrical

Heat Tracing System (I) We start a series of posts talking about the electrical heat tracing elements installed in the field since the way the tracing system is installed in any given surface affects the uniformity of the reached temperature.

AKO´s experience in this matter, in-

stalling our AKOTRACE® solution, the most trusted and used electrical heat tracing system worldwide, gives us a unique vision on how to handle this critical element in any CSP plant. First of all, before starting any installation it is important to double check all materials and plan in advance their distribution following design requirements.

Heating cable

The kind of heating cable to be installed should, besides bringing in the necessary power to compensate thermal loss, endure the maximum process temperature of the plant.

It has to be distributed uniformly, reinforcing its presence in areas with higher probabilities of thermal loss.

If the cable applies more power than it should, the temperature readings will be higher, on the other hand, if it applies less power it can create cold spots, causing problems to the plant´s overall.

Special care should be taken when installing the heating cable in critical points like pipe junctions, to avoid circuit interference operation.

There are some specific criteria to be taken into account when installing redundant heaters, like the distance between themselves or between the cables and the probes, but in any case, both should behave the same way.

The heating cables with mineral insulation should be handled with extra caution due to its stiffness, making its handling more difficult.

Another important characteristic of the heating cable is that changes temperatures, expanding and contracting constantly, thus obliging the installation of an anchoring system capable of enduring such fluctuations.

Finally, the tracing system should not represent an obstacle when replacing, when necessary, elements like valves, probes, etc.

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Temperature probes

The heating elements and the thermal bridges influence the temperature readings measured by the probes.

A probe that is too close to the heating element causes a lower temperature reading. On the other hand, if the probe is installed close to a thermal bridge, the temperature reading will be above the required one.

If the installation requires probe redundancy, they should be installed depend-ing on the configuration defined by control.

In following posts we´ll talk about wiring junction boxes, brackets and how to audit the installation to ensure optimum plant´s performance.

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Optimal installation of the Electrical

Heat Tracing System (II) We continue with the series of post we started a few days ago about the electrical heat tracing elements installed in the field.

This time we are going to focus on wiring

junction boxes, brackets and how to audit the installation to ensure optimum plant´s performance.

Junction boxes and brackets

The junction boxes, used to connect the heating cables or the temperature probes, must be installed in a way that facilitates its access, but, at the same time, they should be protected from rain and must avoid excessive mechanical exposure. Extra protection should be added when the boxes are installed in an area classified as explosive atmosphere.

About the brackets used for the boxes set up, (and installed over the surface where it is necessary to control the temperature) we should take into account that they could cause additional thermal loss, meaning that this point could get cooler. Depending on the situation it would be convenient the use of an additional heating cable extension to compensate for possible thermal losses.

Compliance checks and installation logs

Installation inspection is carried out in two phases: The first one takes place after the installation of the heat tracing system and before lagging.

At this time we have to make sure that all the materials used are undamaged and that the installation complies with the established requirements.

We should take into consideration that any intervention in the electrical heat tracing system after lagging requires its removal, that´s why all the necessary checks have to be made before. This is a critical reminder since any mistake detected can be easily corrected at this point, but after lagging, the costs of any repair just skyrockets.

Among the most important checks we should pay special attention to the installation of the heater and its probes, making sure that all elements are fixed correctly, properly labeled, and, most especially, they should comply with the project requirements.

That´s what AKO has learnt over years of research and multiple installations,

the kind of experience that have made our AKOTRACE® solution the most trusted and used electrical heat tracing system worldwide.

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AKOTRACE® Solution for HTF areas

We continue in this post dissecting our AKOTRACE® Electrical Heat Tracing system, focusing now in our solution for HTF areas.

First of all, let´s establish three critical issues that our solution takes care of:

Maintenance of temperature between 50 and 60 ºC

Focus on temperature maintenance, no heating

Reduction of heat loss

Since in the HTF area we just have to maintain the temperature, between 50-60 ºC, we only need so much power (com-pared to the Molten Salts area) meaning that the tracing system´s energy consump-tion is also low. This reduces thermal loss in areas with higher levels of exposure, that´s the case of valve bonnets, that doesn´t need any extra tracing.

Oscillation levels of temperature in these zones make the ON/OFF regulation the most suitable solution, with a lower number of commutations (start/stop) from the system, allowing the use of contactors to control it, hence reducing unnecessary costs in components. This kind of regulation is available in our DUOControl Trace.

Occasionally, it may be necessary to integrate several sections of trace connected to the same system control. In these cases the use of current probes

along with our AKONet Trace system allows us to identify breaks in any of the legs by detecting a decline in energy consumption.

Taking the above mentioned into account, and thanks to the flexibility of our AKOTRACE® solution, we can reduce costs without losing efficiency, always prioritizing the safety and security of the plant´s process.

In our next post we´ll specify how our AKOTRACE® Electrical Heat Tracing solution works in Molten Salt areas.

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AKOTRACE® Solution for Molten Salt

areas As we promised, this post will now talk about our AKOTRACE® Electrical Heat Trac-ing system, for molten salt areas. First we are going to highlight four critical issues that our solution takes into consideration:

Temperature should be maintained at 265 ºC

There are two kind of tracing circuits: for temperature maintenance and for heating.

Higher levels of thermal loss due to higher temperature readings Tracing is especially critical in this area and requires a higher level of

readiness.

Thermal loss is higher in molten salt areas due to the higher levels of tempera-ture readings that should be maintained. Precision is key when regulating the temperature in this area to be energy efficient and avoid unnecessary overheating. The proper regulation algorithm for this application is the Proportional-Integrated (PI), available in our DUOControl Trace, because it allows each circuit to be more specific regarding the response speed, and at the same time it achieves a very precise and reliable regulation, which translates into temperature fluctuations, with regards to the SP, under a 1 ºC. Since the PI regulation means variable connection/disconnection cycles, the commutation element more suitable is the solid state switch-off relay that allows for an unlimited number of commutations. There are some circuits that require extra power to guarantee two kind of working modes: temperature maintenance and heating. Furthermore, this heating should be done in a limited period of time and making sure not to surpass the materials design temperature. Our DUOControl Trace application has some functionalities to control the heating process during both the ramp-up and the steady state periods. Due to the extra power, the malfunction of any of the control elements could cause an excessive temperature increase. To correct this problem, our AKOTRACE® Electrical Heat Tracing solution offers the option to get a safety contactor that disconnects temporarily that particular tracing section in case it reaches the “Safety Temperature Reading”, generating an alarm in both the operator´s local panel and in the DCS.

There are some critical points that should be treated in a special manner. For these points AKO has specific solutions that have already been used successfully in various plants. AKO´s vision allows for a more adaptable installation, specially designed to cover any plant´s needs, providing each area the necessary resources according to its importance or criticality in the production process.

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PROTrace®: Control and power cabinets

for electrical trace circuits (I) A very important component in any trace installation is the power and control cabinet. Its main function consists on monitoring and managing power from the power supply to the trace circuits, although it can also incorporate subsystems depending on the installation needs.

AKO has a wide range of cabinets with multiple configurations adaptable to any installation needs. According to its structure they can be categorized by:

PROTrace®: They adapt to each plant´s requirements (tower o parabolic through concentrator) and to the application (molten salts or HTF). They provide a high safety standard because they allow, among other things, power supply redundancy in power connections, power sources and probes, as well as monitoring of the cabinet´s performance.

ProTrace Distributed: Designed for projects where there is a large distance between the trace circuits in the electrical rooms (we´ll talk about these ones in following posts)

PROTrace® cabinets

A standard configuration of the cabinets for solar plants (with molten salts storage) contains the following components:

Connection and supply

Include all the generic services: Generic protection, transformers, power supply for system´s control and supply network analyzers. The power supplies and con-nections can be redundant (we recom-mend it in critical processes). In these cases it monitors the quality of the net-work to switch from one connection to another when needed.

Trace control

Gets the information from different elements of the installation (temperature probes and electric current, protections status, framework variables, etc) and acts consequently, modulating the start power in each trace circuit.

Switching

The circuits get connect or disconnected depending on the information gotten from trace control. Depending on the projected switching frequency, that is the preset regulation algorithm, they can be contractors or SSR (switch-off relays). In our next post we´ll continue outlining more components of our PROTrace® cabinets, including our AKODUO safety system.

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PROTrace®: Control and power cabinets

for electrical trace circuits (II) We continue where we left it in our last post, talking about AKO´s PROTrace® cabinets. As we have already stated a standard configuration of the cabinets for solar plants (with molten salts storage) contains the components already mentioned in our last post plus the following:

AKODUO Safety

In case of reaching safety temperature readings, the system disconnects the power supply in the damaged circuit using a second safety contactor. This functionality protects both the heating element and where it is installed in case of malfunction in the switching elements.

Protection

The cabinets have magneto thermal protection and differentials for both the fuse boxes and the trace circuits.

Operator panel

They also have an operator panel to monitor and set up the installation system´s control. Its local installation simplifies any maintenance job both in the fuse boxes and the field.

Fuse boxes monitoring

To ensure the proper functioning of the cabinet, some points are monitored (detection of stress, generic protection status, internal temperature, etc.) generating alarms both in the DCS and in the operator panel. This allows us to do preventive maintenance, avoiding major problems in the fuse boxes and the trace installation.

Communications

The cabinets include the communication network switchers from all the elements of the system´s control: PLC´s, monitoring, operator panel, getaway link with plant´s DCS, and firewall remote management (when applicable). Communications redun-dancy is available to avoid possible link breakages.

Cooling and Welding

They maintain the temperature inside the cabinet within the established ranges in the design phase. It is very common to install the power and control cabinets unsheltered, making the cooling and welding functions very important to ensure the right functioning of all its elements. We still have more to say about AKO´s cabinets. In some other post we´ll describe our PROTrace® Distributed, part of our wide range of cabinets with multiple configurations, adaptable to any installation.

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PROTrace®: Control and power cabinets

for electrical trace circuits (III) We´ve already mentioned that AKO has a wide range of cabinets with multiple configurations adaptable to any instal-lation needs. Now we are going to de-

scribe our PROTrace® Distributed, a cab-inet designed for projects where there is a large distance between the trace cir-cuits in the electrical rooms.

These cabinets differentiate themselves from the rest because they distribute power and control throughout the entire installation by means of three different kinds of cabinets:

Main Cabinet: Distributes power to secondary cabinets and it acts as a liaison between the plant´s DCS and the tracing system. It includes a local panel control

Secondary Cabinet: Distributes power and communications generated from the main cabinet to the PROTrace D3 and/or D6 cabinets.

PROTrace D3 and D6 cabinets: They receive power generated from the secondary cabinets and then they apply this power to the tracing system, regulating it according to its configuration and each circuits probe readings

This structure aims to shorten the distances between the control elements and the tracing circuits, thus dramatically reducing tracing and installation costs.

They are designed for CSP plants with HTF or BOP systems. They are not suitable in sales or in the process industry.

Any change in the main cabinet´s configuration (where we found the panel

control) or in the plant´s DCS, will be sent to the PROTrace D3 and D6 cabinets throughout a communications network, but, nevertheless, each cabinet is autonomous, meaning that they will be working fine even if the network fails.

In our next post we´ll give you more details about our PROTrace D3 and D6 cabinets.

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PROTrace®: Control and power cabinets

for electrical trace circuits (IV) As we promised in our previous post, we are going now to give you more details

about how our PROTrace D3 and D6 cabinets work.

They are available with 3 or 6 control outlets (D3: up to 3 circuits and D6: up to

6 circuits). Each cabinet has two protection elements, independent from each

other, one aimed to control and a second one to power. It includes a contactor per circuit to regulate outlet power, a CPU, our DUOControl Trace (based in an industrial PLC, with high levels of availability and reliability) a remote input

module Pt100 and a resistance welding with thermostat.

Their main functions are:

Circuit alarm management

Start timer circuit to avoid consumption peaks

Temperature supervision per circuit

Independent set point per circuit

2 kinds of control per circuit: ON/OFF and CETA

Independent input per circuit

3 alarm temperature thresholds: mini-mum, maximum and critical (it stops regulation)

Output power set per circuit in case of probe malfunction

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DUOControl Trace: The brain inside

AKO´s ProTrace® cabinets (I)

When talking about the structure of an optimal heat tracing solution we have al-ready highlighted in previous posts the importance of what we call level 2 of the installation, referring to control and power

and where our ProTrace® cabinets are placed. Within these cabinets is where

you´ll find its “brain”: Our DUOControl Trace, a device in charge of integrating the logic of the electrical tracing control, moni-toring the input signals (valves, protection status, alarms) and acting accordingly on the heating elements.

The DUOControl Trace devices have been specifically designed to facilitate the configuration and monitoring of the electrical tracing installation. They use PLC technology, like control hardware, and they provide a high level of reliability to

our DCS-AKOTRACE® system.

Among other functionalities they include the following:

4 temperature probes per tracing control, with several redundancy options Temporary synchronized disconnection for shedding maneuvers Sequential control connection to avoid consumption peaks Up to 10 alarm outputs (depending on the configuration) 24 process alarms per tracing control Independent protection outputs that will disconnect the main output in case of

overheating Theoretical totalizing of consumed energy Transistor output (TRT) that allows for an unlimited number of maneuvers It has 1 or 2 current probes per tracing control, allowing for the supervision of

consumption in single or three phase circuits. SD card slot, which allows to upload or to save the controller configuration to

simplify start off and substitution operations

Its modular construction makes it adaptable to any installation. It can communicate to the DCS plant by means of several protocols: MODBUST/TCP, Profibus, Devicenet, etc.

Each controller can manage up to 32 tracing controls, performing activation work in the heating cables, as well as supervising the protection state and status variables in addition to managing the alarm system.

In our following post we´ll talk about the 3 regulation algorithms (PI, ON/OFF

and CETA) included in our DUOControl Trace devices.

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DUOControl Trace: The brain inside

ProTrace® cabinets (II)

We continue talking about the structure of an optimal heat tracing solution, but

this time focusing on our DUOControl Trace device, the brain inside our ProTrace® cabinets.

We have already stated that depending on the needs of each circuit it has 3

regulation algorithms (PI, ON/OFF and CETA)

PI Control

It is the most appropriate control for areas that require less tempera-ture variation maintenance from Set Point.

The controller is constantly calculating, according to several variables, the necessary power to reach and maintain the Set Point temperature, and it also modulates the output with short term connection/disconnection cycles.

In addition to that, it checks the velocity in which the material gets heated, making sure that it does not exceed its limits.

Each DUOControl Trace has 4 customized PI parameter sets that permit to adjust the speed response independently in each control.

ON/OFF Control

Fit for areas allowing for greater temperature variations from Set Point.

The output remains active until reaching Set Point temperature plus the differential programmed, once it has reached this point, it remains disconnected until reaching Set Point temperature.

CETA Control

This kind of control is suited to compensate thermal losses based on room temperature, avoiding the cooling of fluids inside the pipes.

The controller estimates the necessary power to reach and maintain Set Point temperature depending on room temperature and modulates the output with long-term connection/disconnection cycles.

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AKONet Trace, AKO´s control software

for EHT systems

We have previously stated in several posts that our AKOTRACE® Electrical Heat Tracing system is designed in a three-level structure.

Level 3- Field and Installation

Level 2- Control and Power

Level 1- Supervision and Connectivity

It is in the last level, Supervision and Connectivity, where we find AKO´s newest software to monitor, supervise and control electrical heat tracing

systems.

AKONet Trace it´s been designed to be accessible and easy to use, with great efficiency and enough versatility for optimal performance even in the most ambitious projects.

It´s a web application accessible from a PC and remotely from any navigator connected to the net, even from your phone. One of its setting options includes the possibility to receive alerts via e-mail and/or SMS.

But there is nothing like a live demo on how the application works to give you a

better sense of its functionality and advantages in any CSP plant´s EHT installation.

Watch it on YouTube!

http://www.youtube.com/watch?feature=player_embedded&v=9CDepX5HcBU

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DUOVision Touch Trace: Designed for

small EHT systems We had previously talked about our DUOControl Trace, which we consider to be the brain inside

our ProTrace® cabinets. Now we are going to describe you one device that works along with it: DUOVision Touch Trace.

DUOVision Touch Trace is a 7” high contrast

touch screen that together with DUOControl Trace controllers allows to framework and monitor small electrical heat tracing installations with up to 128 tracing controls, or, in other words, each screen can manage up to 4 DUOControl Trace with 32 tracing controls each one.

Each tracing control regulates the tracing element´s temperature activating and deactivating the heating cables, supervising its protections, as well as the different status variables and the alarm management.

The screen carries out monitoring and frameworking functions, leaving the

tracing management to DUOControl Trace, allowing for the installation to keep on working even when there is a malfunction. Its main responsibilities are:

Creation of tracing control groups when needed: Allows for the organization of different tracing sections in groups, to facilitate its identification during monitoring or frameworking.

Up to 3 user levels, according to its permissions: Visualization, operation and maintenance, which ensures that only qualified people would be able to access and modify tracing installation frameworks.

Easy to use frameworking: Allows to change any installation framework even if you are not familiar with programming.

Graphical identification of control status. Just with a quick look to the screen you can see the installation´s tracing status. When an incident arises (disabled controls, alarms, etc.) the screen will display alarm icons or it will change the regular colors of the control or control group affected by the problem.

SD card slot: Which allows for making system´s configuration backups and restore them when needed, facilitating maintenance work.

Protection level IP 65: Allows for its installation in industrial environments Easy to connect: It only requires power feed and to be connected to the

DUOControl Trace network (Ethernet with RJ45) Theoretical totalizing of consumed energy: It allows to know the theoretical

value of the consumed power.

To recap, the DUOVision touch Trace is the ideal alternative to AKOnet Trace, when working in small EHT installations.

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AKO´s MI heating cable One of the key elements in any electrical heat tracing installation is the use of the right heating cable. In this post we are going to share with you the specifications of AKO´s Mineral Insulated (MI) heating cable.

In any EHT installation, the maintenance temperature and the process temperature determine the kind of heating cable more suitable to use.

The maintenance temperature is usually lower than the process temperature, this fact is determinant to decide the maximum power that the heating cable can endure when connected, while the process temper-ature is needed to avoid the damage of the insulated cable when it is disconnected.

In instances when process temperature reaches 450 ºF readings, or when the maintenance temperature is around 350 ºF, which requires high power from the heating cable, it gets really difficult to pick the right heating cable.

But AKO´s heating cable with mineral insulation can be used in process temper-ature readings of up to 1100 ºF and in maintenance temperature around 900 ºF.

Some other specifications of this cable, besides the power and temperature requirements, are, among others:

Corrosion resistance Mechanical resistance Usable in explosive atmospheres Easy to use

When the corrosion is high, the cable is made with a cover with a high nickel content (Alloy 825). AKO´s MI cable also has a high mechanical resistance, and at the same time, it is adaptable to the surface in which it has to be applied.

The heating element varies regarding the material or diameter depending on the lineal resistance we want to achieve. The material used is a mixture of nickel with other metals.

The heating cable has a heating zone and one or two cold ends to be connected to the power supply. When the cable is 1 core, it has two cold ends for power supply, while the 2 cores cable just has one cold end. When assembled in the power supply, each cable´s cold end includes a cable gland.

The insulation between the cable´s active part and its cover is made out of Magnesium Oxide (MgO).

AKO´s heating cables with mineral insulation are certified to be used in explosive atmospheres classified as Class 1 Division 2, Groups A, B, C & D.

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Temperature Sensors I In this post we will now talk about the different kind of probes used in tracing installations and which one works better depending on the circumstances.

Which probe to use and when

In order to install an electrical trac-ing to maintain a given temperature, it is required the installation of a control loop with a signal provided by a temperature sensor.

When selecting the temperature sensors we have to take into account the tem-perature ranges they will have to endure since the process temperature tends to be higher to the temperature to be maintained by the electrical tracing.

When the temperature ranges are about -60 ºF and 1100 ºF, the temperature

sensor more suitable is a Pt100 probe. For readings higher or closer to the provided temperature, such is the case of solar thermal power tower plants, it´s

better to use a type K thermocouple sensor.

The placement of the sensors on the field close to the traced surfaces entails that they have to be extended to the installation´s electrical cabinets. When

using Pt100 probes we recommend a converter to 4-20mA, making it even

more necessary when installing type K thermocouples. The 4-20 mA signal avoids temperature measurement mistakes caused by possible electromagnetic interferences, which makes its application very common in industrial environments.

AKO has convertors for both Pt100 probes and type K thermocouples to 4-20 mA placed in connection boxes to facilitate its installation.

In our next post we´ll talk about redundancy and the required temperature in different points.

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Temperature Sensors II We continue analyzing the kind of probes used in tracing installations and which ones are more suitable depending on the circumstances.

Where to install a temperature sensor

Now we are going to focus in temperature measurement in different points of the tracing system and its redundancy. Usually there is a temperature sensor in each control area of an electrical tracing installation. But, depending on the criticality of the set up it could be necessary the installation of several sensors in the same area. The distribution of these sensors is made in three different ways depending of the installation´s design requirements:

In a redundancy point

In several points without redundancy

In several points with redundancy

Our controller DUOControl Trace allows for the configuration of the mentioned sensors, and it controls the system based in its temperature readings. Any temperature deviation above a determined value or the damage of a sensor will trigger distinct alarms allowing for a faster and more precise identification of the problem.

In our next post we will talk about AKONet Trace, our software that monitors, supervises and controls electrical heat tracing systems. We will explain in detail how the alarm system works and we will highlight its mobility.

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AKONet Trace: Alarm Management (I) We have already described some of the advantages of our AKONet Trace, the software that allows for the configuration and monitoring of AKO´s electrical tracing installations. In this case we will focus in the alarm management´s functionality.

In any electrical tracing installation the prompt detection of any sys-tem´s anomaly is vital, to both ensure a proper plant´s performance and to avoid future greater and costlier

breakdowns. For that reason AKO has been working relentlessly to provide AKONet Trace software with the right tools to manage this kind of incidents in a rapid and efficient manner.

In case of detecting any anomaly (such as higher or lower temperature readings, mistakes in probes readings, communications breakdowns, etc.), the system activates an alarm that gets displayed on the screen in different ways:

Alarm notification bar: Located in the upper side of the screen, it shows the active alarms in sequence. Pressing over any of the alarms it is possible to gain direct access to the alarm´s listing screen that provides detailed information about the active alarms, offering the possibility to confirm it or get access to the strained control.

Alarm´s listing: It shows the entire installation´s alarm listing, being even able to filter the results throughout different parameters (by dates, by active alarms, by pending confirmation, etc.) The results can be exported to PDF or Excel, facilitating its analysis in operating reports.

In our next post we will continue describing more functionalities of the software including how it works with the system´s control and the categorization of the alarms depending on its source.

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AKONet Trace: Alarm Management (II) We continue with the analysis of our AKONet Trace, the software that allows for the configuration and monitoring of AKO´s electrical tracing installations.

We had previously described two dif-ferent ways the software has to display the alarms on the screen: by means of an alarm notification bar and with an alarm´s listing.

Now let´s see how the software works with the system´s control, plus we will show you how it categorizes the alarms depending on its source.

Control´s active alarms: When reviewing the details of any system´s control, you can detect all the active alarms and even confirm them in case it is necessary.

Alarm´s icons: There are 3 alarm´s icons depending on where they were originated:

I/O Service: Alarms that detect malfunctions in the elements inside the electrical cabinet: internal temperature and electrical protection status of the different electrical elements.

Generics: This kind of alarm gets activated by a cluster, meaning that it can affect all the tracing circuits controlled by the cluster.

Control: An alarm generated by any of the installation´s tracing controls. It also displays an alarm icon in the strained control. When monitoring groups or cabinets, this same icon gets displayed in the strained group or cabinets.

In addition to the above mentioned, to facilitate the problem´s resolution, besides indicating the cause of the alarm, the software also displays the name

of the PLC affected, the name of the control and to which group it belongs, plus the time and date it was generated. These data allows the maintenance personnel to locate and repair the breakdown in a very short period of time.

What´s more, apart from being able to view the alarms in the PC panel where AKONet is executed, all the alarms are communicated to the Distributed Control System (DCS), in exceptional cases when the client demands having the

tracing system´s control connected to the DCS.

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AKO ENGINEERING INC. 1490 South Price Road | Chandler | AZ 85286 Suite 311 | USA Tel. (1) 480 428 5083| e-mail: [email protected]|www.akotrace.com

We reserve the right to supply materials that might vary slightly to those described in our Technical Sheets. Updated information is available on our website: www.ako.com.