What an intelligent control can mean to heat pump performance

Argus Vision heat pump control with advanced user-interface

More and more heat pumps are being fitted with efficient parts such as a DC compressor, an electronic expansion valve and/or an EC fan. the aim is to improve efficiency. However, the use of efficient components alone is not enough because intelligent control is also required to really make a difference.

The compressor in a heat pump system is the primary consumer of energy. A logical choice is therefore to use an energy-efficient DC compressor. The higher output of these DC motors immediately creates a major energy saving. The drive for the DC compressor does require what is called an inverter. A heat pump control with advanced inverter control ensures that the compressor is actually able to be efficient with the required energy and that the power of the heat pump can be controlled on the basis of the heat demand.

With an electronic expansion valve the size of the aperture is controlled by a stepper motor. On the basis of a number of temperature measurements the heat pump control calculates the optimum position for the electronic expansion valve. Proper control of the electronic expansion valve ensures that the heat pump is always able to find an optimum working point. As a result of this the efficiency of the heat pump is increased. An EC fan or EC pump in use generates an energy saving of no less than 60 percent compared to the commonly used AC motors. Via the heat pump control the speed of these types of fans and pumps can also be easily adjusted and, as a result, optimised.

Jan Bron, Manager Business Development at Argus Vision BV, The Netherlands

An integrated weather-dependent control with room temperature compensation harmonizes the heat that the heat pump has to deliver to the actual internal and external temperatures. As a result of this the heat pump control is able to respond immediately to external temperature changes and adjust the capacity if required. This control contributes to the further efficiency optimisation.

For serviceability a good user-interface has become essential, especially with advanced heat pump systems. To start with, the user wants clear status information. Settings and historical data with regard to the appliance components — that are already controlled intelligently by the heat pump control — can now be easily displayed via the user interface. This offers the possibility of generating more specific fault codes.

For air/water heat pumps there are now many component options that can further reduce the energy consumption. To achieve optimum control of these advanced components the role of the heat pump control has become essential. Appliance expertise and integration of control functions have been the decisive factors in achieving a successful end product.

The work group "Environment, Safety and Health" visits a drag finishing unit at König & Meyer

Networking and cooperation enables the companies in the “Hohenlohe Model” to improve their environmental credentials and to advance the region.

When plans were announced in 1991 to build a hazardous waste incineration plant in the Hohenlohe district, an action group was quickly formed. Local industry also supported the cause. To render the building of the plant unnecessary, 17 companies from the region, including ebm-papst, agreed to reduce their volume of hazardous waste by half within three years. This was the birth of the “Hohenlohe Model”.

Since it was first set up, the tasks of the network have changed considerably. Kurt Weissenbach, Chairman of the association, describes the activities of the group: “We help our 180 members to help themselves. On the one hand, we provide support for various projects. On the other hand we have formed internal working groups that deal with the issues of waste, the environment and energy.” For example, the association makes an exchange possible between students and companies. It supports the introduction of environment management systems and assists companies in attaining environmental certification. The association sees itself as a learning network. The objective is to network know-how in order to efficiently realise corporate environmental protection. General manager Jutta Bauer does not only see the cost factor here: “We have seen many cases that demonstrate that environmental protection can also make economic sense.”

The companies pool their ideas regarding sustainable economy and in doing so do not just advance the region, they also assume a national role model function. That can be seen, for example in the country’s very first energy efficiency roundtable. In 2002, ebm-papst and 16 other companies decided to cooperate in order to achieve common objectives with respect to saving energy and reducing CO2 emissions. A project engineer and a moderator supported the companies and gave impetus for the exchange of experience. Company representatives meet three to four times a year at one of the member companies to gain an on-the spot picture of efficient implementation. Personal contacts were quickly established. “When a project like this runs for two years, the people involved get to know each other so well that they call each other directly instead of asking the moderator first,” confirms Weissenbach.

Following the success of this approach, similar schemes are springing to life all over Germany. The Hohenlohe Model is a partner of the “30 Pilot Networks” project of the Federal Ministry for the Environment, which is helping to set up further energy efficiency roundtables in other regions. Here, the association is able to input its own experience and advise other companies and regions. These can benefit from the knowledge of their colleagues. And that is entirely in keeping with the network’s slogan: “No need to reinvent the wheel.”

Dear readers,

Thomas Borst
Managing Director Sales Group Management

Mr Beilke, what do you mean by organic growth?
I am convinced that healthy growth in the global economy can only be organic. Artificial bubbles will always burst. We all run our companies at full load while business is booming, so it is natural that the crisis will hit hard when it hits. By contrast, organic growth is orientated towards, for example, population growth. The world population is increasing at a net rate of just under 80 million per year. At some point in time, these people will become consumers. They will want a television set, a refrigerator and a car. organic grow is derived from this. But taking account of innovation to satisfy the new latent needs, I consider growth of between three and four percent per year to be organic. Only on this scale is growth sustainable and largely free from setbacks.

But we will not be able to escape the cyclical ups and downs?
We have just experienced 20 successive quarters of growth. At the moment we are in a period of decline. In truth, we all knew that the growth couldn’t go on for ever. McKinsey has followed 400 companies over the last 30 years. The result: After three to seven years of above-average results, even the top performers drop back to the pace of industry in general. Even though we at ebm-papst are relatively invulnerable because we have the benefit of being an innovation leader, we still have to learn how to stay in the fast lane, and to view normality as the exception. otherwise, we risk losing our appetite and becoming sluggish. Accordingly, the consequence is to use the period of decline to set the foundations for future growth. It is worthwhile using the time to shake off bad habits and to carefully scrutinise established processes. This is easier to do in times of decline than it is in times of growth.

How does ebm-papst compensate for market fluctuations?
Like many other companies in Germany (and unlike ten years ago), we are able to adapt better today by making use of working time accounts and short-time working. These instruments give Germany a relative advantage as an industrial location. Two further facts give ebm-papst additional advantages that will lessen the impact of the crisis. Firstly, we are globally present and broadly diversified. This allows us to compensate for developments in different industrial sectors. Secondly, growing environmental awareness around the world helps us to market our energy-efficient motors and fans, even in times of crisis. We were the first to recognise this trend.

Which key markets do you have in your sights?
The solar industry, pellet heating systems, wind power, heat pumps and condensing boiler technology – in these five future segments alone we can offer appropriate solutions for all issues relating to air, climate and drives.

Dear readers, 2009 will not only be remembered as a year of crisis, it is also the Darwin bicentenary. The great naturalist would have been 200 years old in February. In the light of his theory of evolution, one thing becomes apparent: It is still not size that ensures the continued existence of a species, of a company or of a whole industry. It is its ability to change and adapt. Those that embrace change fastest and implement change best will emerge strongest from the current crisis. “Exploit the crisis” is the motto with which we appeal to our customers and partners to pull together on our common path of innovation. We are convinced that the foundations must be laid today so that we are fit for the next round of evolution tomorrow. And innovation is the opportunity for us to haul ourselves out of the quagmire of the crisis and to reach this stage of evolution. This is more than just whistling in the dark, something that is demonstrated not just by the huge amount of positive feedback from our customers, but also by hard facts. We are noticing that orders which had previously been stopped are now being called off after all, that new projects are being fed into our development department and that follow-up orders are being placed.

And when the markets come back to life, the demand for innovative, energy-efficient solutions will grow in a wide variety of industrial sectors. We and our customers are well prepared for this. Not least thanks to EC technology. In all output classes, this is among the best that is available on the market, and even today it hugely undercuts the limits of the IE3 energy classification due to come into force in 2015. The next stage of evolution can come: We are ready.

Thomas Borst
Managing Director Sales Group Management

Why there are different fan designs

Moving air and creating pressure at best efficiency and with least noise emissions. This is one way to describe the objective of fans. For many applications, they are the best option also because they create a continuous flow, have small space requirements and have only few moving parts. To understand which fan design (centrifugal, axial or mixed) is the best for a specific application, one needs to look at the basic mechanism of fan operation.

Depending on pressure

In principle, the fan blades of an axial-flow fan deflect the airflow from an axial inflow direction into a helical flow pattern thereby increasing the (total) pressure across the rotor. To get higher pressure, larger flow angles to the rotating blades are required. However, this principle has natural limits. When the relative flow angle becomes too large the aerodynamics becomes less efficient and the detached flow creates increasing noise.

In cases where more pressure rise is required, centrifugal forces are used in addition to the blade aerodynamics. since every fan is a rotating system, the air is always exposed to centrifugal forces. Beyond their best operation point, the flow in axial fans develops a strong centrifugal component, while large portions of the flow path are aerodynamically blocked due to recirculating air. Effectively, the fan operates like a smaller but poorly designed centrifugal fan in this regime. For those applications, a dedicated centrifugal design is the best choice. In centrifugal fans, centrifugal forces contribute significantly to the overall pressure build-up, in some cases they are the dominant mechanism. Axial fans are best applied to cases, where a fairly small pressure rise and large flow rates are required, while centrifugal fans are able to deliver higher pressure together with smaller flow rates for similar external dimensions and speeds.

New methods

With these basic considerations the actual design can be started. In the past, fans were designed mainly experimentally and a powerful experience base has been established over the years. Today, computational fluid dynamics (CFD) methods are applied to the aerodynamic design process. CFD is used in all kinds of systems where heat and mass transfer is important. For entirely new fans as well as for optimising components like blades or blade-tips. In principle, the aerodynamicist can design a new fan without prior knowledge of the fan type because the CFD method represents a comprehensive mathematical flow model. It is often easier to perform so-called numerical experiments than conducting an experimental campaign, especially since the CFD-results allow for very detailed analyses of the flow field.

With CFD, blade performance, loss and noise mechanisms or the interaction of the flow with walls can be understood and improved for every operating point of interest. In times where high efficiency and cost-effective solutions are key drivers, the aerodynamicist tries to squeeze out every possible percent of the available design space. The curved and twisted blades of modern fans or the specific blade tips are examples of such efforts. With state-of-the art design tools it is possible to design the fan for a specific application rather than trying to tailor an existing fan to a new application.

Together with the success of CFD, the focus of the experiments has changed from being a basic design method to be a necessary verification and validation method of the overall performance on one hand and to verify (or dismiss) the impact of features like guide vanes or downstream diffusers on the other hand.

Michael B. Schmitz, Dr.-Ing. Manager R&D Aerodynamics and Simulation ebm-papst St. Georgen

Problems with heat in your electronic systems? Ask André Runge – he knows how to simulate properly

Fans are needed wherever heat has to be dissipated. In close collaboration with Delta IDL, ebm-papst make sure that they are optimally employed. The engineering specialist based at Greifswald in North Germany is a specialist in simulating heat and air flow. since 2002, the experts have offered heat dissipation concepts and constructions for large and small customers, as well as its own self-developed products. What form the collaboration takes, and what chances and risks are inherent in heat and flow simulation, are explained by Delta IDL founder and managing director André Runge.

Can the benefits of simulation be expressed in figures?
No. That would be difficult. The key advantage compared to measuring is that the cause and effect can be seen. For example, just because the acoustics and temperature are right when measuring, it does not necessarily mean that the optimum status has been achieved. Simulation allows a one-to-one depiction that shows the exact flow characteristics. In some cases, you can see that a piece of metal plate is all that is needed to screen off or redirect the flow – and the customer’s whole problem is resolved. But the difference is hard to express in figures unless you are conducting measurements and simulation in parallel. It all becomes clearer if you conduct virtual tests on different versions of a product, in other words once the simulation model has been defined. You can then enjoy an impressive benefit in terms of time.

Where are the limits of simulation?
We are able to offer such good simulation because we have the experience and because besides our own measurements, we employ measuring reports from the customer to verify our simulations. You cannot expect satisfactory results without experience in simulation tools. But you will always encounter applications in which practical experimentation is better than theoretical study, in which we also use measurements to support the simulation. This is done in particular when there are too many external factors that you cannot influence yourself or which you cannot precisely define.

So the major source of error in simulation is human?
Human and trust in the data used. The most important thing is communication. We often find that the “language” used within one project differs from one industry to the next. Sometimes it even differs within a single industry, technically speaking. We work with checklists, for example, to prevent any misunderstanding.

What precise form does the collaboration with ebm-papst take?
Starting with the concepts, we try to identify the appropriate fan. If we cannot find anything off the shelf, if we need measuring results, characteristics curves under particular pressure conditions or samples, we place a direct enquiry. ebm-papst researches quickly and without fuss. Together, we then define the optimum solution for the customer, enabling him to reduce, for example speed, and thus cost, energy and noise. It is a very close collaboration.

What moved you to use the fans yourself?
For our own products, we quickly decided to take this route because of something we have learned from the experience of our customers: They sometimes selected cheaper fans from the Far East, for reasons of cost. These rarely satisfy expectations with respect to noise, air performance or warranty. so at the end of the day they are not really cheaper at all. At ebm-papst we get the best products available on the market.

This 3D simulation of an electronic unit shows flow characteristics

Teddington air curtains keep the cold air out and energy consumption low

Money can be made from hot air. In the well-climatised sales room of a supermarket, customers demonstrate greater disposition to spend money and the staff absentee rate drops considerably. But if the doors are frequently opened, the warm air needs to be continually replenished to maintain the feel-good climate. This is because the natural exchange of air causes the warm air to flow out of the upper section of the door and cold air to flow in. A door air curtain system stops this undesirable exchange with a flow of warm air that helps to save up to 80 percent in energy costs.

Saving with pressure

The company Teddington from Westerwald, Germany, employs a pressure-chamber nozzle set in its energy-efficient Evolvent air curtain systems. In the pressure chamber, the airflow is compressed, distributed evenly via convex nozzle cheeks and emitted as an accelerated stream. This forms a homogeneous curtain over the complete blow-out width, which screens both the room and high door openings from the outside air. Compared to a conventional laminar system, the Evolvent pressure-chamber nozzle set offered by Teddington requires less air and offers energy savings of up to 40 percent – the unit’s own requirement for heat energy. The Evolvent nozzle devices offer this benefit for all applications.
And these are extremely varied: From screening air-conditioned rooms, through “locking in” unpleasant smells, such as those encountered in waste disposal sites, to screening large industrial portals. While a constant air curtain that is as quiet and convenient as possible is required in the entrance area of a department store, a four metre high portal to a factory hall requires a high output. ebm-papst is the R&D partner of Teddington for optimising the air-side device output. “We are responsible for everything that moves the air,” explains Winfried Schaefer, regional sales Manager, “and we supply a wide range of different products, from the axial fan, through dual inlet centrifugal blowers to backward curved centrifugal blowers.” The different performance requirements of the Teddington systems are covered in two ways: by the different sizes of the various products and by the number of blowers used in the system. The systems are modular in their design so that several blowers can be used alongside each other, depending on the output required and the width.

More EC

Teddington happily makes use of the well equipped test and experimentation research and development facilities offered by ebm-papst Mulfingen. Following extensive measurements, the entire product range was optimised at the beginning of 2009 with respect to noise development and power. “More and more end customers are discovering EC technology, which we offer as an alternative to the AC standard,” reports Schaefer. For example, if you consider a large shopping centre, in which the doors are open from morning till evening, the air cushion system fitted with EC fans quickly pays for itself. This ensures a constantly pleasant climate, and does so even more energy-efficiently and even more quietly. And that helps the customers to feel good as well.

Originally developed especially for respiration devices, the “Turtle Blower” has since become established as a robust universal genius

The housing is what gave the Turtle Blower its nickname. The small black plastic case with the five screw bosses and the blower outlet are reminiscent of a small turtle. The task that the apparent reptile fulfils is revealed by its product designation: CPAP centrifugal blower ECI 30.20. The compact blower was developed for medical respiration aids. It supports patients suffering from irregular breathing by ensuring that they have sufficient air supply. As the device is used right next to the patient’s bed, the little turtle has to be mainly capable of two things. Firstly, it has to be very quiet, and secondly it has to respond dynamically and positively to the patient’s respiration requirements. But it can do a lot more than just that.

Staying power

Ten years ago, engineers at ebm-papst in St. Georgen recognised that their expertise in air technology and drive engineering was predestined for use in developing blowers for helping sleep apnoea patients. The early devices were bulky and heavy. That changed in 2003 when the Swedish respiration device specialist Breas decided that it wanted to market a more user-friendly model, following the trend in medical technology of offering more compact devices that were not restricted to a specific point of use. Work started on the measuring rigs and in the development laboratories at St. Georgen: “The market for CPAP blowers was born in our laboratories in 1999, but the starting shot for the Turtle Blower was the joint project with Breas in 2003,” explains Product Manager Claudius Klose. “The ECI 30.20 drive that was developed then was the original model for the drive in the Turtle Blower.” The engineers converted the motor previously used from an external to an internal rotor motor, making a huge step in miniaturization possible. “The Turtle Blower is four times smaller than its predecessor, yet it has a greater power range and weights just half a pound,” summarises Klose. For use in CPAP respiration devices, the blower has to satisfy specific requirements. It supports the body’s respiratory reflexes with a controlled supply of air. Its air flow and pressure must be continually adapted to the patient’s own breathing. The blower drive must therefore be able to adjust its speed with extreme flexibility. The development engineers at St. Georgen designed the blower to be suitably dynamic for a maximum operating point at which a pressure variation of four to 20 millibars is possible within the space of 200 milliseconds.

Vacuum cleaning? Lawn mowing? Nowadays, that is done by robots: automatically, quietly, reliably and without grumbling

Look who’s mowing the lawn, ask the neighbours as the Automower® glides across the lawn, as if by magic. The blades of grass are cut to size all over, apparently without any recognisable pattern. At the same time, a flat, prehistoric-looking creature is crawling over the parquet and carpets. The Trilobite leaves nothing but a dust-free floor behind as it makes its way through the apartment. Household robots are playing an ever greater role in relieving us of our chores in house and garden. This is made possible by EC technology.

High performance in a small space

An extinct arthropod from prehistoric times inspired Electrolux to develop the world’s first fully automatic vacuum cleaner, the Trilobite, at the turn of the millennium. Flat and as nimble as its prehistoric namesake, the robotic vacuum cleaner glides over the floor without colliding with anything. The fact that the floor is then sparklingly clean is made possible in part by ebm-papst.
Electrolux developed the blower sections itself. Then the Swedish household appliance specialists needed a motor to match, a motor that could satisfy the rigorous demands on the aspirator, and which was also cost-effective. “The limited space meant that the required air performance could only be achieved by using a high speed,” explains Achim Labitzke, Product Manager at ebm-papst in St. Georgen. However, for reasons of cost, only a single-phase Variodrive motor was possible. This is usually employed in compact fans with a power draw of ten watts. Now it should draw 55 watts at 18 volts to generate a speed of up to 18,000 rpm. “We reconciled the cost aspect and the power requirement by optimising the motor output and developed a powerful suction drive,” explains Labitzke.
Optimised efficiency is essential for good battery performance. After all, the suction drive uses two thirds of the Trilobite’s energy. The single-phase EC motor achieves an efficiency of
75 percent despite the high speed. This creates an overall efficiency of 45 percent for the blower. That is some 10 percentage points more than a mains-powered vacuum cleaner. And despite this extreme mechanical load, the blower motor has a service life of more than 2,000 hours.
Moreover, the EC motor is by its very nature quiet. To enable the complete blower to have a maximum noise level of 75 decibels, additional acoustic optimisations were performed in St. Georgen. Now, the fully automatic vacuum cleaner buzzes through the apartment without disturbing anybody talking on the phone or watching TV.

The pioneer of robotic vacuum cleaners. The Trilobite works out the most efficient way of cleaning a room. It uses ultrasonic waves to detect and circumvent obstacles. If used regularly, it will reduce manual vacuuming to about once a month.