Energy saving in the life-sciences- Opportunities and ...

Energy saving in the life-sciences-Opportunities and Risks

Gordon FarquharsonAugust 2015

© PharmOut 2013

Agenda

1. The business case - Where the energy is consumed.

2. Energy saving opportunities in HVAC systems

› Systems level – Design Concepts

› Operational – Set back

› Component - GEP

3. The regulatory/compliance view.

4. Don’t forget the “black stuff”!

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HVAC focus – business case50-80% of site energy is used in

HVAC (Heating, Ventilation and Air Conditioning)

Use mostly for Fan Power and Cooling systems (chilled water)

Pfizer Inc have reported that’s over $250,000,000 per year !

(ISPE Brussels HVAC 2009)

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HVAC energy saving opportunities

Systems conceptual design

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Full fresh air with heat recovery

Comparing three different Outside Air treatment options

ProcessRoom 2

ProcessRoom 1

ProcessRoom 2

ProcessRoom 1

ProcessRoom 2

ProcessRoom 1

Treated make-up airNo Fan

Treated make-up airwith Fan

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Yearly cost of 10.000m3/h air for classified area in Tianjin China

0

20000

40000

60000

80000

100000

120000

140000

Once through

system

Recirc with passive

precon

Recirc with active

precon

DK

K, to

tal an

nu

al

Electricity for Fans, Drives

and motors

Steam for humidification

Electricity for cooling and

De-humidification

Steam for heating and Re-

heating

Comparing three different options

Annual comparison 10 000m3/hr Tianjin China

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Yearly cost of 10.000m3/h with the three systems in mid France wheather

0

10000

20000

30000

40000

50000

60000

70000

80000

Once through with

recovery

Recirc with passive precon Recirc with active precon

DK

K, t

ota

l an

nu

al

Electricity for Fans, Drivesand motors

Steam for humidification

Electricity for cooling andDe-humidification

Steam for heating and Re-heating

Comparing three different options

Annual comparison 10 000m3/hr NW Europe

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Let’s look at design conceptsTechnology options for Grade A

• Recirculation via central air handling units (AHUs) feeding terminal filters

• Fan/Filter modules

Fan/Filter module

Ducted air handling systemsceiling terminal filter

VS

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Technology options for Grade A

• Recirculation via central air handling

Grade A UDAF Room/Zone

AHUFan + Pre-filter + Sensible cooling

Supply air to terminal filters

Ducted return air from room Low Level

Pressurisation make-up air (%RH controlled by this air)

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Technology options for Grade A

• Fan/Filter modules• Generally rare except China & Israel.

Grade A UDAF Room/Zone

Return air from room Low Level

Pressurisation make-up air (%RH controlled by this air)

Fan/Filter modules Mounted on ceiling frame

Plenum mounted over cleanroom Sensible heat

cooling coils

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Let’s think about the fan energy use comparisons

• 24 m2 of Grade A UDF zone.

• 10 m3/s air volume to ensure 0.45 m/s average face velocity.

• 1200 x 600 mm filter and FFU units – say 34 units.

• Central AHU solution

› 10 m3/s fan

› Typical system static pressure 1200 Pa

› Fan motor power required ~25 kW

• FFU solution

› 10 m3/s via multiple fans ( one small fan in each of 34 FFUs)

› Each FFU fan motor 320 W = ~11 kW

› If this operated continuously, the annual saving would be about 70 tonnes of CO2.

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BUT, we don’t all like the design Fan-filter module example (ceiling void)

Large plenum sits on top of cleanroom

Requires access for maintenance (usually)

Each module separately controlled

Plenum and ducts must be very low frictional resistance

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Component level

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Energy Efficiency at Component Level

• Fan & drive

› High efficiency motors

› Permanent magnet motors

› Variable speed drives (VSD)

• Filters

› Optimised selection, low pressure drop.

• Ducting & AHUs

› Size for low pressure drop

› Low leakage

• Constant volume controls

› Select for low pressure drop or use externally powered

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Centrifugal Fan Today, variable fan speed is the best way to control the air volume or pressure developed.

Variable frequency drives also give “soft start” capability.

Drive and bearings are source of particles. HEPA or FINAL filters must be downstream for Pharma applications.

Centrifugal FanMotor in airstream

Motor Power = Dp x Air Vol/ efficiency

Noise

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Backward curved centrifugal fan

Advantages:•High fan efficiency at 75 to 85% •High efficiency almostunchanged at VAV operation•With correct selection of belt drives optimal motor efficiency can be achieved across a large range of fan speeds.

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Plug fan

Advantages:•Low investment cost•Efficiency almost unchanged at VAV operation•No efficiency loss from motor to fan•Relative small pressure loss at fan outlet

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Motor/Fan Drive Belts

• For centrifugal fans the standard transmission type is a belt between a pulley on the motor shaft and a pulley on the fan shaft.

• This makes gearing between the motor and fan revolution speed possible, but introduces also an energy loss, due to friction between the belt and the pulleys.

• In order to optimize the belt-pulley efficiency, the following should be observed:

› Use as few belts as possible, minimum 2

› Use pulleys with a diameter of at least 180 mm on both motor and fan

› The belt pulley system shall be perfectly aligned and with the correct tension to be verified by a tension gauge

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Bench marking fan efficiency

• Some engineers set GEP benchmarks

• Specific Fan Power (SFP) is a useful tool.

• The factor SFP = electrical power consumed/air volumeSFP = kw/m3/sec

• Divide the power supplied to the VSD by the system airflow

• Good SFP factors are:~2 for simple ventilation systems.~3-6 for classified cleanroom area systems

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Variable speed drives

• Efficient frequency converter Variable Speed Drives (VSD) should be considered for all HVAC fans to control the motor and hence the fan speed.

• Avoid using VSDs to allow lazy design.

• Mount VSD frequency control near to load.

• Use the pulleys to optimize the operating speed/frequency for the fan motors at 100% air flow and pressure. Use VSDs to compensate for filter clogging or to deliver variable flow.

• For direct drive fans it is not simple to optimize the operating frequency after installation, so extra care should be taken to calculate the systems pressure drop and meet the “near nominal” operating speed/frequency at 100% air flow.

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Fan Static Pressure vs Flow

A common mistake : running fans in the unstable “surge” range

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Permanent magnet motors

• Permanent magnet motors have synchronous rotation (no ‘slip’ as the standard motor)

• they used to be very expensive and only used where the precise speed of rotation was needed

• Today they can be acquired at a small extra cost

• Better accommodation of direct drive

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HEPA filters have a minimum efficiency at a certain particle size which is

dependent on velocity of the air through the media

Good filtration practice

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Good pre-filter practice

• Large filter areas

› to reduce pressure drop = less energy.

› to improve filter efficiency due to lower velocity.

› To increase service intervals = more dust holding capacity.

• Avoid low capacity G4 type panel filters.

• Use glass fibre filters. Use bag and compact types.

• e.g. F7 + F7 gives better efficiency than G4 + F9

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Example: Good low Dp filter pressure drop practice

Filter class Maximum start pressure drop [Pa]

Recommended pressure drop at filter change[Pa]

G4 25 50

F6 80 160

F7 100 200

F9 125 250

Inline HEPA filters 150 300

Terminal and UDF HEPA filters

125 250

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Operational considerations

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Energy Efficiency “Operational” controls

• Reduction or set-back relaxation during silent hours.

› Temperature and RH

› Air velocity set-back UDF systems.

› Air volume set-back non-UDF systems.

› Turning systems off may also be ok for some less critical areas (e.g. secondary packaging).

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Permanent reduction in airflow

• Original systems are usually over-designed (design margin).

• At time of design you only have estimates of heat gains, particle loads, etc.

• After 12-18 months you have much better understanding.

› Now is the time to consider trimming = e.g. air volume reduction.

› Use available data to reduce whilst maintaining control at the required levels

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Operational ControlsSilent hour Temp and RH relaxation

• Normal practice in commercial properties.

• Stay in control but relax set points or control bands during silent hours.

• Restore control to defined levels in advance of processing start-up (qualify this time).

› Allow temp rise in summer, drop in winter.

› Widen RH band.

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The potential savings - UDF

• Significant fan energy and some cooling energy can be saved by air velocity reduction:

› Reduce UDF velocity from ave 0.45 to 0.3 m/s.

› In my example, fan volume would reduce from 10 m3/s to 6.7 m3/s, and the resistance in the system would reduce by ~75% .

› So this would give rise to a fan power saving of 10-15 kW during silent periods.

› Depending on the use of the facility, and the amount of “set-back” time available, this might be worth investing in.

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The potential savings – non UDF

• Some fan energy and some cooling energy can be saved by air volume reduction:› Reduce non-UDF system volumes from 3015 air

changes/hr for a Grade B area, and 2510 for a Grade C area as examples.

› Such air volume reductions would give rise to reductions of around 50% in the fan energy consumed.

› Again, depending on the use of the facility, and the amount of “set-back” time available, this might be worth investing in.

• But there are some complications for cleanrooms(also applies to other pressurised spaces)

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Essential system components for pressure control with volume set-back

• Be aware, systems become more complex, hence greater cost, C&Q, maintenance, and failure potential (The RISK).

• Constant volume supply to each room needs to be reset. Requires a VAV device.

• Room return air needs to be VAV to ensure fixed differential between supply and return air volume. This to maintain pressurisation leakage.

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Essential system components for pressure control with volume set-back

++

Supply VS

Return VR

Leakage VL is fixed for constant fixed room pressure

Supply Vs has 2 settings Vs & 0.3 Vs

Return VR needs 2 settings, or to be active control

VR1 = Vs – VL

VR2 = 0.3 VS - VL

Leakage VL

P

Active control or 2 position fixed volume

2 position constant volume

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Regulatory perspective

• No demands or requirements.

• In EU, pressure from mainly Nordic nations, for a sustainability dimension in the EU GMP has been resisted so far.

› Concerns that we just export our pollution to emerging nations.

› Governments are seduced by low potential lower cash cost of medicines.

• GMP position is therefore purely focussed on our responsibility to prove the measures we decide to deploy are effective, and don’t compromise product quality.

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Risks

• Unsurprisingly - Generally risks found to be inversely proportional to the proximity to the most critical processes:

› Sterile products HVAC systems

› Highest profile due to potential adverse impact on critical cleanroom performance and cleanliness attributes.

› OSD HVAC systems

› Critical utilities

› Secondary packaging HVAC systems

Highest Risk

Lower Risk

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The “black stuff”• Amazingly this is often forgotten. The black

utilities……..

• Aspects to consider are:

› CHP (combined heat & power).

› Alternative de-humidification systems.

› Use of liquid desiccant systems (Lithium Bromide solution)

› New/upgraded chilled water systems

› Electrically commutated motors (EC)

› Refrigerant liquid pressure amplification (LPA)

› Electronic expansion valves (refrigerant)

› Optimal systems – 2 port; dual temperature systems.

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Thank you for your time.Questions?

Gordon Farquharson

[email protected]

Executive Consultant

www.pharmout.net

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