There is demand for effi­cient and, most impor­tantly, quiet air/water heat pump systems suit­able for indoor, outdoor or hybrid use, which use natural refrig­er­ants and whose output can be intel­li­gently adapted to the actual condi­tions. This requires fans that not only operate econom­i­cally at optimum effi­ciency and pleasant noise levels, but can also commu­ni­cate and be intel­li­gently networked. As the noise and power consump­tion of the speed-controlled compressor drive also have to be factored in, there is an addi­tional need for inverter elec­tronics that reduce oper­ating noise through optimum commu­ta­tion and simul­ta­ne­ously improve the energy effi­ciency of the heat pump. 

Heating with heat pumps

Today’s heating systems demand concepts based on renew­able ener­gies. ebm-papst delivers low-noise and effi­cient compo­nents.

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Fans and inverter elec­tronics for quiet oper­a­tion

Motor and fan specialist ebm-papst supplies various types of effi­cient and acousti­cally opti­mized EC fans for air/water heat pumps. For partic­u­larly noise-sensi­tive outdoor areas, for example, there are two axial ranges that are espe­cially suit­able for use with natural and flam­mable refrig­er­ants and are extremely quiet thanks to their special design (Fig. 1). This prevents the heat pumps from becoming a disrup­tive factor and allows them to blend in well with their surround­ings. While the AxiEco plug-in is suit­able for heat pumps requiring a large pres­sure reserve for the evap­o­rator, the AxiTone is geared more towards deliv­ering higher air flow at low back pres­sure when the heat pump design requires this. 

Based on many years of expe­ri­ence with EC motors, their commu­ta­tion elec­tronics and heat pump appli­ca­tions, the company has also devel­oped inverter elec­tronics (Fig. 2) with an elec­trical output of up to 3.5 kW, 7.5 kW and 12 kW, respec­tively, which are suit­able for speed-controlled perma­nent magnet synchro­nous motors (PSM) such as those that are often used in heat pump compres­sors. The commu­ta­tion process has been opti­mized over a period of decades and signif­i­cantly reduces noise levels. At the same time, it improves effi­ciency, thus increasing the COP (coef­fi­cient of perfor­mance) value of the terminal appa­ratus by several percentage points.

Design and testing

EMC compat­i­bility was taken into account when devel­oping both the inverter elec­tronics and the energy-saving EC fans. For example, inte­grated three-phase active power factor correc­tion (active PFC) ensures the optimal EMC prop­er­ties of the inverter elec­tronics and EC fans. No addi­tional measures are required to comply with the stan­dards with regard to current harmonics. Given that, depending on the size of the heat pump, conven­tional expan­sion valve assem­blies can easily weigh up to 20 kg, consid­er­able weight and space savings are achieved by using inte­grated active PFC. The wiring effort is also reduced.

Fig. 3 In the EMC test labo­ra­tory, the immu­nity to inter­fer­ence and inter­fer­ence emis­sions can be measured in compli­ance with the stan­dards on test units up to 60 m³ in size and 20 t in weight. (Photo | ebm-papst)

The EMC Labo­ra­tory at the Mulfingen site is in oper­a­tion since 2021. (Photo | ebm-papst)

Fig. 4: The ferrite tiles and pyramid-shaped absorbers facil­i­tate the simu­la­tion of a free field envi­ron­ment. (Photo | ebm-papst)

Spread over two floors, the EMC test labo­ra­tory covers a total area of 2,500 m². (Photo | ebm-papst)

At ebm-papst, all EC fans and elec­tronics are tested in accor­dance with the state of the art and using the consid­er­able engi­neering exper­tise of the large EMC labo­ra­tory at the Mulfingen site, which has been in oper­a­tion since 2021. It is possible to measure the response to both conducted inter­fer­ence in the cables and inter­fer­ence emis­sions, i.e. elec­tro­mag­netic waves that travel through the air.

Large-scale EMC tests

Spread over two floors, the EMC test labo­ra­tory covers a total area of 2,500 m². Much of this space houses the shielding and absorber rooms needed for the EMC measure­ment tech­nology (Fig. 3), in which more than 100,000 ferrite tiles and over 4,000 pyramid-shaped absorbers are installed (Fig. 4). On the one hand, the rooms shield against external sources of inter­fer­ence; on the other hand, they facil­i­tate the simu­la­tion of a free field envi­ron­ment. Here, the immu­nity to inter­fer­ence and inter­fer­ence emis­sions can be measured in compli­ance with the stan­dards on test units up to 60 m³ in size and 20 t in weight.

These test units not only stem from the company’s own devel­op­ment activ­i­ties, but also include entire customer systems such as heat pumps with propane as the refrig­erant. After all, it is not only the compo­nents installed in the heat pump that must comply with the rele­vant EMC guide­lines. The heat pump manu­fac­turer must prove that, during oper­a­tion, its entire system does not inter­fere with other elec­tricity-consuming appa­ratus in the network and is also not subject to inter­fer­ence itself. Put simply, this means that starting the heat pump in the garden does not cause the tele­vi­sion in the living room to flicker.

The manu­fac­turers of heat pumps are familiar with the chal­lenges that need to be addressed. For example, unfa­vor­ably routed cables often cause EMC prob­lems. It there­fore makes sense to check EMC compat­i­bility before actual certi­fi­ca­tion so that the time to market is not delayed unnec­es­sarily. Multiple test cycles are often neces­sary and slots are diffi­cult to come by in many test labo­ra­to­ries. For this reason, ebm-papst offers its customers the oppor­tu­nity to test entire systems in its labo­ra­tory, serving as a devel­op­ment partner and providing access to its many years of heat pump expe­ri­ence (Fig. 5). EMC distur­bance can then be detected and elim­i­nated at an early stage (Fig. 6), enabling the heat pump to be brought to market more quickly.