PBTI_PR_AUTOADAPT

GRUNDFOS PRESS RELEASE

The Grundfos R&D team behind the development

of the AUTOADAPT algorithm

AUTOADAPT – one small step for Grundfos, one giant leap for installers and end usersA look inside the heart of Europe’s best circulator: ALPHA2 from Grundfos and its unique AUTOADAPT function. Get the full techni-cal insight – from algorithms to field tests – and meet the brains behind this revolutionary circulator technology.

WHAT, WHY, WHO

Adaptive control of domestic circulatorsThe ALPHA2 circulator from Grundfos offers total control of domestic heating systems by means of the ingenious AUTOADAPT function. Developed and patented by Grundfos, AUTOADAPT ensures the optimum combination of comfort and energy consumption in heat-ing systems for one and two-family houses. Always!

Because it makes perfect sense AUTOADAPT is the heart of the ALPHA2 circulator. It ensures that your heating system pro-vides optimum comfort and uses as little energy as possible at all times – in much the same way as your heart controls your body. Just imagine your heart running at full speed regardless of whether you are asleep or out running. Or not being able to automatically regulate your pulse up and down when you need to. Not very comfortable and a total waste of energy. One touch of the AUTOADAPT button and you are on your way to great comfort and great energy savings.

Brainy Grundfos R & D engineers behind radical innovationCombining over 60 years of circulator know-how and application understanding with some of the world’s most innovative R&D engineers provides the basis for the most radical inno-vation in the pump industry for decades.

The Grundfos development team gives you the full insight into the AUTOADAPT algorithm.

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HOWConstant pressure at all load conditions is essential for how well the thermostatic valves can control the heat emission from the radiators, see Fig. 1. It is a well-known fact that optimum circulator control in a heating system is best obtained by controlling pump pressure on a proportional pressure curve, see Fig 2. However, predicting the best position in real-life applications is rather difficult, because the optimum position depends on correlated factors such as the size of the heating system, the boiler type, the load condition, etc. This is where AUTOADAPT steps in to ensure the circulator is controlled in an optimum manner.

The AUTOADAPT algorithmThe objective of the AUTOADAPT algorithm is to measure and analyse the heating system during operation and adapt to the current heating pattern. The overall benefits are easy setup for installers and increased comfort and energy savings for end users, because the system adapts to night vs. day opera-tions, summer vs. winter season, and heat losses or gains affecting room temperature, for example, from radiators, walls and windows, sun radiation, electrical equipment, and people.

Basically, AUTOADAPT optimises the position of the proportional pressure curve via a three-step task as illustrated in Fig. 3.

The “System Analyser” analyses the heating system, which the circulator is a part of. On the basis of the analysis, AUTOADAPT verifies whether the circu-lator pressure is too high, too low, or correct. The “Curve Selector” then uses this knowledge to select the optimum proportional pressure curve for the circulator. Finally, the circulator is controlled according to the selected proportional pressure curve by means of the “Proportional Pressure Control”.

Circulator

valvev1 v2

Boiler

RadiatorRoom 1 Room 2

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Pump max-curve6 m

Fig. 1 Central heating system with a two-pipe system, which is the most used system in real-life applications.

Fig. 2 Proportional pressure curve used for control of circulators. The light-red area illustrates the area where the curve can be placed. The optimum place-ment is dependent on the type and size of the central heating system.

Fig. 3 AUTOADAPT’s 3-step task

System Analyser Curve Selector Proportional Pressure Control

AUTOADAPT

What does it do?The AUTOADAPT setting continually analyses and finds the setting where opti-mal comfort meets minimal energy consumption. It automatically delivers perfect comfort at the lowest possible energy level.

What’s in it for me?Installer:• easyinstallation• automaticsetting• demand-controlledoperations

End user:• optimumcomfort• energysavings• reducedCO2 emissions

What’s new?The second generation AUTOADAPT :• Adapts totherequirementsof theheatingsystem

before reaching the maximum pump curve

• AllowstheALPHA2pumptoadjusttheproportionalpressure curve both up and down

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The System Analyser & the Curve SelectorThe thermostatic valves control the water flow through the radiators by means of the circulator pressure. The valves do this best, if the pressure across these is constant at all load conditions. Monitoring of the load conditions of the heating system forms the basis for the subsequent adaptation of the proportional pressure curve. Load conditions are analysed through monitoring of the average opening of the valves. The average opening can be calcu-lated from the pressure and flow measurements available at the pump. In the following the average opening is denoted ksys-value.

The functionality of the System Analyser is further explained in figures 4, 5 and 6. The orange curve shows changes in ksys-value over time. The red and blue curves are the maximum and minimum ksys-values. Finally, the black curve divides the area between the red and blue curve into two sub-areas denoted area A and area B (denoted kref ).

In Fig. 4 the circulator pressure is too low. This can be seen by the fact that the orange curve is in area B for a larger amount of time than in area A. When the pressure delivered by the pump is too low, the heating system cannot deliver sufficient heat to the system, which means that the valves are fully opened most of the time. This is why the orange curve is in area B most of the time. To accommodate the large opening of the valves, AUTOADAPT’s Curve Selector increases the pressure by moving the proportional pressure curve upwards. The result is an optimised heating system with increased comfort.

In Fig. 5 the circulator pressure is too high. This can be seen by the fact that the orange curve is in area A for a larger amount of time than in area B. When the pressure is too high, the heating system delivers excess heat, which means that the valves are closed most of the time. This is why the orange curve is in area A most of the time. To accommodate closed valves, AUTOADAPT’s Curve Selector decreases the pressure by moving the propor-tional pressure curve downwards. The result is an optimised heating system with reduced energy consumption.

In Fig. 6 the pressure has a reasonable value for the given heating system. This can be seen by the fact that the orange curve is equally distributed between area A and B. In this case AUTOADAPT’s Curve Selector will verify that the preset reference duty point is correct and not change the position of the proportional pres-sure curve.

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Fig. 4 Example of a time series of ksys-values in a cen-tral heating system, where saturation occurs when the valves are almost open.

Fig. 5 Example of a time series of ksys-values in a cen-tral heating system, where saturation occurs when the valves is almost closed.

Fig. 6 Example of a time series of ksys-values in a cen-tral heating system, where saturation does not occur.

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PROOF

Extensive field tests in Denmark, Germany, Great Britain, Belgium, and the Czech Republic have demonstrated that AUTOADAPT keeps its promises and makes a significant difference with respect to comfort and energy savings. AUTOADAPT has been able to select lower con-trol curves than the initial curve in most of the test cases. This indicates that it is possible to save electrical energy in many applications without affecting the comfort of the heating system.

The tests documented that:

• In15%ofthesystems,therequirementoftheheatingsystemexceededthereferenceduty point. AUTOADAPT selected a higher proportional pressure curve and provided increased comfort to the end user.

• In73%ofthesystems,therequirementoftheheatingsystemwaslowerthantherefer-ence duty point. AUTOADAPT selected a lower proportional pressure curve and provided energy savings to the end user.

• In12%ofthesystems,therequirementoftheheatingsystemmatchedtheinitialrefer-ence duty point.

MORE

For more information about ALPHA2 and AUTOADAPT visit www.poweredby.grundfos.com

For more information about the AUTOADAPT algorithm and field tests contact Portfolio Man-ager Martin Andersen at [email protected]