Can Voltage Optimisation Save Energy in the ......5 Test procedure To obtain consistent results, the AHUs were set to run in a static mode. This maintained a static pressure of 800Pa

1 ©Energy Efficiency Consultancy Limited 2017 All Rights Reserved

Can Voltage Optimisation Save Energy in the Pharmaceutical Sector?

Andy Butterworth

Shuji Chen


Contents 1 Executive summary .............................................................................................................................. 3

2 Introduction ......................................................................................................................................... 3

3 Description of Voltage Optimisation .................................................................................................... 4

3.1 Types of load ............................................................................................................................. 6

4 Case study utilising EECO2 cleanroom test facility .............................................................................. 7

5 Test procedure ................................................................................................................................... 10

6 Results ................................................................................................................................................ 10

7 Discussion ........................................................................................................................................... 13

8 Conclusion .......................................................................................................................................... 13


Outline

EECO2 is a leading global provider of researched, tested and proven engineered efficiency solutions

for the pharmaceutical, biotech and other high-tech industries.

Our team of dedicated experts have a wealth of experience in supporting organisations to

substantially reduce energy and water consumption, costs and associated greenhouse gas and CO2

emissions, whilst maintaining or improving industry compliance and safety. As an independent

consultancy working in the life sciences sector we rigorously test, where possible, all energy saving

solutions before we recommend them to a client.

At the request of several of our pharmaceutical/life science clients we tested a Powerstar Voltage

Optimisation unit and published our independent findings.

1 Executive summary

The objective of the testing procedure, and consequently this whitepaper, was to determine

whether energy savings could be achieved in the Pharmaceutical sector by installing Voltage

Optimisation (VO) technology.

To ascertain this, we tested a Powerstar fixed voltage unit with a preset reduction of 10v in our

cleanroom test facility. The cleanroom is state of the art and it is fully VSD controlled.

We recorded an energy saving of 0.9% on equipment efficiency, 3.48% saving due to a process

defined as negative power or ‘back EMF’ and a 3.45% energy saving on a single‐phase motor.

Therefore, the full savings on our cleanroom facility was 4.38%.

In older facilities where the use of energy saving equipment and VSD control is not as prevalent,

these savings could be higher. However, there is less opportunity for energy savings with newer

installations due to the already increased efficiency of newer equipment, therefore a full site

survey must be carried out before installing a VO unit to determine the benefits.

2 Introduction

Voltage Optimisation (VO) is a technology that has been developed for many years and at one

time there were many companies selling this technology. However, in recent years this has

reduced to several key players within the field. There are many claims about the energy savings

and benefits of installing a VO system, mostly by the manufacturers but often backed up with


client case studies.

As claims of savings vary widely between sector and installation we at EECO2 wanted to

investigate typical savings within the pharmaceutical and life sciences sector. We aimed to validate

any savings and show any disadvantages within a typical pharmaceutical site by carrying out real-

time data collection at our Grade B/C cleanroom test facility.

3 Description of Voltage Optimisation

As a rule, power is supplied at a higher voltage than is necessary. Most electrical equipment in the

UK is rated at 220V. The supply can vary from 253V to 230V with the average being 242V. This

excess voltage can be considered as wasted energy. Three phase supplies can vary between 438V

to 400V. Three phase equipment in mainland Western Europe was rated nominally at 380V. The

UK three phase equipment was rated at 415V. This is now “harmonised” to 400V although nobody

intentionally generates at 400V.

As shown in Fig. 1, the VO unit is basically a transformer that reduces the incoming voltage to a

predetermined optimal voltage for the site. A fixed VO unit reduces the voltage by a specific

amount (in our case 10V). As the incoming voltage varies, the resultant supply voltage varies. It is

worth mentioning that with a variable VO system the optimal supply voltage can be maintained

irrespective of the incoming mains voltage.

The VO system we tested (Powerstar) is based on the same principle but utilises its own

patented design to enable additional savings to be obtained through a process referred to by

them as negative power or ‘back EMF'.

As Fig. 1 illustrates, Powerstar’s system differs from the aforementioned ‘standard’ because whilst the

supply current flows from the first winding to the second winding, Powerstar has introduced a

third winding.


Fig. 1 General VO system vs. Powerstar VO system

This third winding creates the negative power in the opposite direction (back EMF) resulting in

excess voltage being chopped creating a reduction in voltage and current. This current is real

energy, not apparent or reactive, so there is a direct effect on the consumption of the load. This

can be seen as energy savings in KWh.

Powerstar also states within its literature that the installation of a VO system can reduce harmonic

distortion (see Fig. 2). Harmonics are voltages or currents that operate at a frequency that is a

multiple of the fundamental frequency. So, with a 50Hz fundamental waveform, a 2nd harmonic

frequency would be 2 x 50Hz = 100Hz. A 3rd harmonic would be 3 x 50Hz = 150Hz and so on.

Harmonics are created because electrical or electronic devices, such as motors, ballasts, variable

speed drives, and other inductive loads, have voltage‐current characteristics that are non‐linear.

Harmonics can be negligible in some cases, but many businesses report experiencing problems

such as overheating and less efficient running of equipment as a result of harmonics, so reduction

of them is widely considered to be desirable.

Another statement from Powerstar is the VO systems ability to improve power factor (see Fig. 3).

Whilst VO equipment does not specifically seek to do so, it is mentioned as an additional benefit of

doing so, although if a site suffers from particular power factor problems, additional measures may

need to be considered.


Fig. 2 Reduced harmonics by applying the Powerstar VO system

Fig.3 Improved power factor by using the Powerstar VO system

To conclude, voltage optimisation systems, in particular the one we obtained from Powerstar,

claim to reduce the wasted energy that results in a supply voltage of between 216V and 253V due

to varying distances from the power station, allowing a business to only pay for energy required by

a site whilst, additionally, filtering out harmonics, phase voltages and giving a smoother power

supply, extending equipment life.

3.1 Types of load

There are two types of electrical load. Voltage dependent and voltage independent. A voltage

dependent load has a power consumption proportional to the voltage supplied to it, such as a


tungsten filament lamp. Whereas, a voltage independent load has a fixed power consumption

whatever the voltage supplied to it. This is the case with computer equipment. The voltage is

always stepped down via a transformer to the operating voltage of the equipment.

Most loads are a mixture of both, such as electric motors. Their design, type, size and efficiency all

influence its voltage characteristics. As there are no savings to be made with voltage independent

loads it is important to know the site load structure.

You are more likely to see energy reductions with purely inductive loads, which induce magnetic

fields, such as in an electric motor, but you will also see some energy reduction with resistive

loads, such as incandescent light bulbs. However, when the resistive load is required for a heating

effect, this will take longer, resulting in no savings.

As sites have a diversity of loads and can vary significantly, it highlights the importance of a full site

survey to determine the types of load and identify potential savings, as not all loads can benefit

from VO and a business case must always be viable before proceeding.

Modern installations generally have less opportunity for savings due to having almost no

incandescent lighting, high‐frequency fluorescent lighting, variable speed drives and high motor

efficiencies for which there is little or no ability to generate savings on.

It is worth noting that regardless of the loads present to a site, there should always be potential

savings if a Powerstar system is installed and there is overvoltage being supplied, this is due to

negative power (back EMF).

4 Case study utilising EECO2 cleanroom test facility

Most, if not all, cleanrooms are in constant use. Therefore, there is limited opportunity for testing,

particularly as the tests must be repeatable and undertaken in a controlled environment.

At our office based in Macclesfield, we have a purpose built, fully operational grade B/C

cleanroom. It has the various gowning up areas and air locks (as shown in Fig.4.). The test facility

has been built to a high‐quality finish with full vinyl ceilings, walls and floors.

The facility consists of 2 main test rooms with the associated airlocks and change rooms for each

level of classification. The facility can be set up to represent a room cleanliness classification up to

and including Grade B (ISO 5).

This is supplied by two air handling units (see Fig. 5) that can be configured independently in several

ways to vary air change rates and supply characteristics.


Fig. 4 Schematic of the operational grade B/C cleanroom

Fig. 5 Photograph of two air handling units


The fan duties are:

AHU1 Supply Fan 4kW 7.3A FLC 3 Phase

AHU1 Extract Fan 1.45 kW 1.64A FLC 3 Phase

AHU 2 Supply Fan 0.75 kW 1.7A FLC 3 Phase

AHU2 Extract Fan 0.36kW 1.6A FLC Single Phase

All are supplied by VSDs. AHU2 Extract fan is supplied by a Sontay speed controller.

Fig. 6 indicates other equipment:

2 No. LCD Display screens 42”

1 No. LCD Display Screen 32”

2 No. Computers c/w 19” display screens

6 No. 4’ Fluorescent lights (inductive ballast) 28W

4 No. 5’ Fluorescent lights (inductive ballast) 36W

Office lighting 16 2’ Fluorescent lights (inductive ballast) 18W

The load profile is approximately 15% voltage dependent and this is from the fluorescent lighting.

Fig. 6 List of equipment

Main DB to Cleanroom

Lights L1 AHU Control Panel

Lights L2 AHU Control Panel

Toilet Hand drier L3 AHU Control Panel

L1 Fume Cupboard

Office Sockets L2 Corridor Lights

Sockets L3 Sockets

Sockets L1

Sockets L2 Chiller

Sockets L3

Data cabinet L1 Control Panel

Lights L2

Lights L3

Door locks L1 Control Panel

Boiler L2

L3

Shower L1

L2

L3


5 Test procedure

To obtain consistent results, the AHUs were set to run in a static mode. This maintained a static

pressure of 800Pa in AHU1 supply and 400Pa in AHU1 extract. This resulted in an ACR of 17/h in

CR3 – Test Room 1 and an ACR of 40/h in CR6 – Test Room 2 (as shown in fig. 4), maintaining the

pressure cascade.

All the lights were switched on, as were the LCD monitors and the two PC’s to create loads of

different types (voltage dependent and independent). The light levels were taken at various points

with VO unit on and off.

A Carlo Gavazzi EM271 meter was used to obtain the instantaneous values from AHU1 Supply and

extract fans, AHU2 Supply and extract fans and the main incoming supply. The main incoming

supply was measured after the VO unit which gives overall savings on equipment efficiency and

after the main meter and before the VO unit, which measures the savings due to back EMF. Care

was taken to ensure the correct reference voltage was used.

6 Results

The measured results are shown in this section including the readings of the Carlo Gavazzi EM271

meter (see Table 1), the measured curves for voltage, current, current Total Harmonic Distortion

(THD), voltage THD and apparent power (see Fig. 7-11), and the cleanroom lighting levels (see Table

2).


Table 1. Meter readings with the VO system on and off

Location VO On (Lux)

VO Off (Lux)

Storage Area 1264 1230

Main Cleanroom 55 49

Back Entrance 470 375

Office 1340 1324

Table 2. Cleanroom lighting levels

Meter Readings Cleanroom ACR1

239/424V 230/298V % Difference

Phase Voltage Amps kW kVA kVAr Pf Phase Voltage Amps kW kVA kVAr Pf

1 238 5.13 0.86 1.22 0.7 1 238 5.11 0.82 1.22 0.67

2 239 7.82 1.82 1.87 0.97 2 239 7.82 1.76 1.87 0.94

3 241 6.95 0.77 1.67 0.46 3 241 6.81 0.75 1.64 0.46

Total kW 3.45 Total kW 3.33 3.48

Back EMF

Savings

239/424V 230/298V % Difference


1 236 6.65 1.53 1.57 0.97 1 227 6.9 1.52 1.57 0.97

2 237 7.71 1.75 1.83 0.96 2 228 7.82 1.73 1.78 0.97

3 239 5.08 1.15 1.21 0.95 3 229 5.22 1.14 1.20 0.95

Total kW 4.43 Total kW 4.39 0.90

Equipment

efficiency

Savings


1 237 3.51 0.76 0.83 0.91 1 227 3.53 0.76 0.80 0.95

2 238 3.53 0.79 0.84 0.94 2 228 3.74 0.80 0.85 0.94

3 239 3.54 0.79 0.85 0.93 3 229 3.75 0.80 0.86 0.93

Total kW 2.34 Total kW 2.36 0


1 237 0.55 0.10 0.13 0.77 1 227 0.58 0.09 0.13 0.68

2 238 0.58 0.11 0.14 0.8 2 228 0.6 0.09 0.14 0.66

3 239 0.57 0.12 0.14 0.88 3 229 0.59 0.10 0.14 0.74



1 237 0.45 0.07 0.11 0.66 1 227 0.43 0.06 0.10 0.61

2 238 0.49 0.07 0.12 0.6 2 228 0.47 0.07 0.11 0.65

3 239 0.47 0.08 0.11 0.71 3 229 0.46 0.08 0.11 0.76


Amps Voltage kW kVA kVAr Pf Amps Voltage kW kVA kVAr Pf

1.83 237 0.29 0.4 0.67 1.83 227 0.28 0.4 0.67 3.45

Savings on

Single

Phase Fan

Main Meter before VO: VO Off Main Meter before VO: VO On

AHU 2 Supply Fan VO Off AHU 2 Supply Fan VO On )

AHU 2 Extract Fan VO Off (single Phase) AHU 2 Extract Fan VO On (single Phase)

Main Meter after VO: VO Off Main Meter after VO: VO On

AHU 1 Supply Fan VO Off AHU 1 Supply Fan VO On

AHU 1 Extract Fan VO Off AHU 1 Extract Fan VO On


Fig. 7 Voltage Fig. 8 Current

Fig. 9 Current THD Fig. 10 Voltage THD


Fig. 11 Apparent power

7 Discussion

Overall, we observed an energy saving of 0.9% on equipment efficiency, 3.48% saving due to back

EMF and a 3.45% energy saving on the single‐phase motor (see Table 1). This is with a load profile

of 15% voltage dependent loads. Energy consumption within our cleanroom test facility is rather

small so we only witnessed small changes, but this can be scaled up as a percentage, and this is

what we would expect to see.

This test has shown that ‘Back EMF’ accounts for 80-81% of VO savings, with the remaining 19-20%

coming from improved equipment efficiency.

It can be seen from Fig. 7 that our supply voltage varies by about 5V. We have a reduction of 10V

when the VO unit is switched on. As we have a fixed VO system there is still a 5V fluctuation on the

supply voltage with the VO unit on. If we had a variable or electronic-dynamic VO system installed

this would be much smoother.

The current (Fig. 8) is steady. We can see where the AHU was off and observe a slight spike on the

yellow phase when the VO unit was switched on. This smoothed off in a short time (approximately

30 minutes).

There was approximately a 5% improvement in the current total harmonic distortion with the VO

unit on (Fig. 9). The spike is when the AHU was switched back on.

The voltage THD (Fig. 10) is below the 5% maximum harmonic distortion factor (IEEE Std. 519)

and there is a very slight improvement with the VO unit on.


From Table 1 there is an improvement in apparent power (kVA) but this is so slight that it is not

visible in the graph (Fig. 11).

From the readings taken from a light meter (Table 2) there was a slight reduction in the light

levels which is to be expected with the fluorescent lighting. This was not apparent to the naked

eye.

The supply velocity pressure from both AHUs was monitored to ensure there was no loss of flow

with the VO unit on. The velocity pressure remained constant.

8 Conclusion

We conclude that energy savings with VO are not guaranteed. Due to a number of extraneous

variables, savings vary quite considerably from site to site. Larger savings will be seen with older

equipment, especially inductive loads such as fixed speed motors on fans and chillers.

Our tests were carried out on highly efficient, relatively new plant. The motors are small, but the

lighting is standard fluorescent tubes. As expected there were no savings on the three‐phase

supply and extract fans with VSD controllers; however, there was a small saving on the single‐

phase motor (see Table 1).

As shown in Table 1, the saving on the main incoming supply was 0.9% due to equipment

efficiency savings and 3.48% due to ‘back EMF’, hence a total saving of 4.38% was achieved. This

is what would be expected on an installation of similar size and load mix.

Fig. 7‐11 show the readings taken from the Powerstar HMI over a 3‐day period including the

voltage harmonics, current harmonics, current total harmonic distortion (THD), voltage THD and

apparent power harmonics. Initially, the VO unit was off and on the 19th turned on. The

reduction on voltage can be seen going from 240V to 230V (see Fig. 7). As the VO unit is fixed

there is no smoothing on the incoming voltage. There were no significant improvements in the

power factor or the harmonics. The peaks and troughs in the middle of the readings were due to

the AHU being restarted. The light levels were slightly reduced with the VO unit off (see Table 2).

There are some savings to be made with VO in the pharmaceutical sector but the savings will

vary. Therefore, it is my professional recommendation that before any VO unit is installed a full

site survey must be undertaken to ascertain the types of equipment and the age of equipment

installed. The previous 12 months half-hourly energy data must also be reviewed.

Documents

Can Voltage Optimisation Save Energy in the ......5 Test procedure To obtain consistent results, the AHUs were set to run in a static mode. This maintained a static pressure of 800Pa