RadiPac: Docu­men­ta­tion and fan selec­tion

Fig. 1a: Cata­logue nominal data

Selec­tion of the right fan on the basis of an appli­ca­tion-specific oper­ating point is only possible with reli­able data and is gener­ally performed with the aid of appro­priate product selec­tion soft­ware. The prop­er­ties of the RadiPac centrifugal fans are docu­mented in product data sheets and printed cata­logues (Fig. 1a, b, c) as well as in a product selec­tion program, the Product Selector. At ebm-papst, the origin of the fan perfor­mance data contained in the soft­ware can always be traced back to measure­ments as described above. The required air flow and the static pres­sure increase which the fan subse­quently has to achieve in prac­tical use are the minimum criteria employed for the selec­tion process.

Opti­mised soft­ware

Fig. 1b and 1c: Cata­logue char­ac­ter­istic curves

Because the required oper­ating points are not always iden­tical to the measured oper­ating points, there is a need for inter­po­la­tion between the measured values. Use is often made for this purpose of the familiar affinity laws for flow machines. These are suffi­ciently accu­rate in cases where fans merely consist of a flow machine, in other words an impeller. As we already know however (ARTICLE THE FAN), ebm-papst fans also include a motor and control elec­tronics. These two assem­blies do not conform to the fan affinity laws, but rather exhibit completely different perfor­mance char­ac­ter­is­tics, partic­u­larly in the partial load range. The selec­tion soft­ware has been appro­pri­ately opti­mised to obtain a highly accu­rate fore­cast of the oper­ating behav­iour of the fan unit at any conceiv­able oper­ating point.

Product Selector

Fig. 2: Vali­da­tion test on a total of 38 different fan models from ebm-papst

The Product Selector from ebm-papst provides a partic­u­larly user-friendly means of finding the right fan. The selec­tion program makes it possible to check fans at various oper­ating points and deter­mine the perfor­mance data. It addi­tion­ally permits dynamic compar­isons closely resem­bling actual oper­ating condi­tions. The influ­ence of temper­a­ture, alti­tude and instal­la­tion space can also be incor­po­rated. If there are several fans in the spec­i­fied perfor­mance range, the aero­dy­namic and acoustic data displayed can be used to help select the most suit­able model. Another option avail­able is calcu­la­tion of the life cycle costs for the fans selected. The perfor­mance data are also output at the spec­i­fied oper­ating point with suction and pres­sure side sound power level values over the octave band. The soft­ware can be incor­po­rated into customer device config­u­ra­tion programs by way of a DLL inter­face.

Certi­fied accu­racy

Fig. 3: In reality, fans from ebm-papst tend to have a higher effi­ciency level than shown in the product docu­men­ta­tion

The perfor­mance data output is extremely accu­rate, as confirmed by the inspec­tion author­i­ties (TÜV Süd). Vali­da­tion measure­ments performed on all 38 models in the RadiPac product range show that on average the effi­ciency level indi­cated by the Product Selector tends to be slightly too low! What proce­dure was employed for the vali­da­tion measure­ments? 15 refer­ence points (Fig. 2) were chosen for each fan in the RadiPac product range. These were measured on the certi­fied chamber test rig and the perfor­mance data were then compared to the data from the Product Selector. This revealed that the calcu­lated values from the Product Selector are almost iden­tical to the values actu­ally measured. In accor­dance with AHU guide­line 01, the best possible accu­racy class 0 is thus obtained for RadiPac fans (Fig. 3). In other words, ebm-papst RadiPac fans in as-deliv­ered condi­tion tend to exhibit a higher level of effi­ciency than that indi­cated by the Product Selector. This guar­an­tees true plan­ning reli­a­bility for customers.