Increasing energy efficiency in an electroplating company (Part 3)

3 Analysis of the current status

3.2.1 Ventilation systems for extracting the electroplating baths

Fig. 13: Illustration of the bathrooms and the ventilation systems for area 1 [IB Potthoff]The supply air is fed into area 1 via air inlet openings in the building envelope.

A pre-separator is installed within the duct system for baths 2, 3 and 4.

Furthermore, the extract air is additionally cleaned with a central scrubber. A central fan is installed downstream of the scrubber.

 

The exhaust air from bathrooms 5 and 6 is each cleaned with a separate scrubber. A fan is installed downstream of each scrubber.

 

The data of the three central fans of the same type and the air exchange rate of area 2 are shown in Table 6.

 

As in zone 1, the supply air is fed to zone 2 via air inlet openings in the building envelope.

 

The hall (static) and the supply air (dynamic) are also heated here via recirculation heaters.

 

Fig. 14: Illustration of the bathrooms and ventilation systems for area 2 [IB Potthoff]Figure 14 shows the existing exhaust air systems with the associated bathrooms for area 2.

 

There is no supply air system corresponding to the exhaust air systems. As a result, considerable draughts occur, particularly in the cold season.

 

A large amount of energy from the production area is dissipated unused via the exhaust air systems, as heat recovery systems are not installed.

 

Determining the air volume flows of the relevant bathrooms

_VH2 = c - l - t - ή - _ρ/KoH2 Eq. <1>

Where are:

Accordingly, the minimum volume flows listed in Table 7 must be produced at the respective baths to avoid explosive mixtures.

 

Designation	Unit	Value
Volume flow Bath 1	m3/h	3000
Volume flow bath 2	m3/h	3000
Volume flow bath 3	m3/h	3000
Bath volume flow 4	m3/h	6000
Bath volume flow 5	m3/h	3000
Bath volume flow 6	m3/h	4000

Table 7: Required extraction volume flows of the baths

 

Fig. 15: Power consumption of the exhaust air fans in the bathrooms [IB Potthoff]As described above, the volume flows operated by the fans are not known. In order to be able to make an initial rough estimate of the volume flows of the fans in the actual state, the measured active power consumption of the fans over the period 1.2.2017 to 10.2.2017 is evaluated below. The evaluation is shown in Figure 15.

Based on the electrical power listed in Table 7, the operating volume flow is evaluated using the following equation <2>.

V$_2$ = V$_1$ $\cdot$ $\frac{P_2
^3}{P_1^3}$ Eq. <2>

Where are:

3.2.2 Process heating and cooling

Fig. 16: Electricity output curve for the baths and reactive power generation [IB Potthoff]Process heating

 

To maintain the required galvanic conditions such as

• Maintaining a constant bath temperature
• Creation of an almost homogeneous electrolyte
• maintaining the required heating time before the electroplating process begins

Fig. 17: Ordered annual duration curve of the electricity demand of reactive power generation [IB Potthoff]The evaluation of the electricity consumption of reactive power generation over the year 2017 is listed in Table 10.