Cutting Energy Costs For Pharmaceutical Research
we were putting about 10°F into the makeup air simply ... MAKE–UP. AS. 3. AIR SEPARATOR. N. RUN–AROUND–COIL HEAT RECOVERY FLOW DIAGRAM. PHASE IV ...
Cutting Energy Costs
For Pharmaceutical
Research
Fume Hood Exhaust
This article
illustrates how a Cutting Energy Costs with
pharmaceutical
research firm Laboratory Workstation Fume
reduces costs for
heating Hood Exhaust
conditioned
makeup air by
30% or more for by Paul A.Tetley
thousands of
dollars in annual
savings.
L
aboratory facilities at pharmaceutical re- This pharmaceutical research organization
search and manufacturing organizations was confronted by the prospects of high energy
are burdened with perhaps the most ex- costs when it recently built a new facility for
pensive energy costs for heating and cooling per chemical research activities. The company is
sq. ft. in the country. This is mainly because involved in research and early stage develop-
most laboratories — and some pharmaceutical ment of drugs. While the company is indepen-
processing facilities — require conditioned 100% dent, it occasionally forms collaborations with
makeup air for their workstation environments. pharmaceutical manufacturers, setting up in-
Obviously these demands are responsible for dependent joint ventures for both production
creating substantially higher energy costs since and marketing of specific drugs it helped to
makeup air must be filtered, heated, cooled, develop.
humidified, or dehumidified depending upon Even without the need to introduce 100%
circumstances. makeup air into the work environment, labora-
There is a practical, cost-effective method, tory research activities at pharmaceutical firms
however, to lower energy costs for natural gas, are major energy consumers. Providing com-
oil, or electricity significantly with resultant fortable and safe workplaces for scientists and
savings of thousands — or even hundreds of technicians requires efficient heating and cool-
thousands — of dollars annually. This article ing of ambient air. Workstation fume hoods
will discuss how one pharmaceutical research require control and management and other en-
organization1 handled this problem. ergy intensive equipment and systems associ-
Figure 1. Mixed flow impeller system.
PHARMACEUTICAL ENGINEERING • SEPTEMBER/OCTOBER 2001
Fume Hood Exhaust
OA Temp Space Hum.
36.1 °F 18.6 %RH
F+B % Open Command ON Smoke Status
OA Hum. HRC DAT
0.0 ON NORMAL
87.0 %RH 49.9 °F Status
O.A. S.A.
COOLING COIL
Pre-Filter
Status
36.1 °F 75.8 54.9
DIRTY
OA Temp % Closed DAT Temp/LL
After-Filter
Status H.W.S.
CLEAN
H.W.R. C.H.W.R. 50.4
HTG LOCKOUT 60.0 °F C.H.W.S. 59.8
Sup. Static Pressure 0.0%
CLG LOCKOUT 60.0 °F
% Open
NORMAL RESET SCHEDULE
AHU-1 Status
Space Discharge
Suction Static ON Temp. SetPoint
NORMAL 75.0 55.0
65.0 65.0
Phase IV AHU-1 Control Calculated SetPoint:
60.0 °F.
HTG S.P. - 3.0 °F.
Figure 2. System status monitor – outside air temperature at 36.1°F.
ated with the research environment generally consume energy cludes both the ambient air as well as the laboratory worksta-
in one form or another. When you add fume hood exhaust tion fume hood exhaust, and is considered as “100% exhaust,
systems on the roof – which must operate whenever a worksta- 100% makeup.” This facility is a “constant volume building,”
tion is being used – it’s easy to see how energy costs can mount which means that the volume of air entering and exiting the
quickly at a large research facility. At this firm, about 30,000 building is constant. “With the cost of heating or cooling
cu. ft. of air per minute has to be moved in and out of its new makeup air alone at nearly $4 per cu. ft. per year, clearly this
20,000 sq. ft. research building which houses 18 laboratory issue had to be studied carefully, and a reasonable solution had
workstations, each with 10' fume hoods. to be found,” the facility manager commented.
The facility manager2 at the company is responsible for the
daily operation of the company’s physical plant. He is involved The Solution was on the Roof
in many areas including construction, renovation, energy The facility manager’s approach to the problem was both
conservation, and other aspects of managing a complex facil- practical and logical. In fact, most of the solution was already
ity. He benchmarks the average cost to condition makeup air in place, just above his head. That’s because the 18 laboratory
at $3.71 per cu. ft. per year. He said this figure is used by most workstation fume hoods were being exhausted on the building’s
building engineers. On the other hand, the total energy costs roof with mixed flow impeller exhaust systems — Figure 1. Each
average more than $6 per sq. ft. per year. system is connected to an exhaust plenum serving the work-
Since code prohibits all air in the laboratory workstation stations, and is designed to provide high efficiency exhaust and
environment to be recycled, it must be exhausted. This in- eliminate re-entrainment problems, a particularly critical
SEPTEMBER/OCTOBER • 2001PHARMACEUTICAL ENGINEERING
Fume Hood Exhaust
issue when makeup air is introduced into a building on a The Pharmaceutical Industry Experiences “High
constant flow basis. End” Energy Costs
The systems are designed to accommodate a unique heat In fact, he added that one of the influences with regard to com-
recovery system (essentially a heat exchanger containing coils mitting capital expenses to energy reduction is related to
filled with a solution of glycol and water) that extracts ambient “rebate dollars from the local utilities.” He said that, “if you are
heat from the workstation fume hood exhaust before it is looking at two projects and one is rebatable and one is not, all
discharged above the roofline – Figure 4. This air glycol/water other things being equal, you go after the rebate dollars.” In
solution is transferred to the supply air handler to preheat the light of this, he discussed energy cost averages for the pharma-
conditioned air entering the building. As a result, the amount of ceutical industry, adding that it is not uncommon to see $6 per
natural gas to preheat the makeup air is reduced substan- sq. ft. per year for energy costs. Since he has an extensive
tially. facility management background in other industries, he added
that for comparison purposes, public schools run at about $1,
Reduce Heating Costs 3% for each I°F Added and hospitals (also large energy consumers) are still below $5
The facility manager said that in winter, “there were days when per sq. ft. per year (these figures are based on Northeast
we were putting about 10°F into the makeup air simply regional facilities where energy costs are slightly higher than
by capturing heat from the exhaust stream” – Figure 3. He the rest of the US). He stressed that the pharmaceutical indus-
added that 10°F was the temperature difference between the try is at the “very high end” of energy costs.
incoming air (at the outside ambient temperature) and the air When questioned further, the facility manager said the
entering the intake system after it was passed through the main reason for this is the 100% conditioned makeup air which
glycol loop coils. He stated that “for every degree you add, you is required by code. In a hospital, for example, 80% of the air
reduce your energy costs about 3%. So, a 10°F rise in intake air in an operating room can be recirculated as long as it’s filtered
means that about 30% of energy savings can be realized.” As he through a HEPA system. In the pharmaceutical industry, “we
says, “In addition to saving our company money, we also help have no opportunity for recirculating air. We just could not
contribute to a cleaner environment since less fossil fuel is bring it back into the building.” You can’t use it through a heat
consumed.” wheel which is a way of recovering heat from exhaust air since
With regard to overall costs – for system hardware as well as many of them are based on not only getting the sensible heat
energy charges – the facility manager believes that a out of the air, but the latent heat out of the moisture. In a
payback cycle of three years or less has made this solution chemical building or a drug research facility, this is not
economically sound for the company (some users have experi- possible.
enced actual payback in two years or less depending upon
system configuration, climate, and other variables). With Heating Energy Costs are Expected to Soar
energy costs rising dramatically, it is expected that heating When discussing energy costs and the future, the facility
costs alone will rise 30%-50% for the 2000/2001 season over the manager said he expects some “serious increases in natural
prior year, and he believes that the company has gone in the gas prices in the near future.” He added that, for example, he
right direction with its heat recovery systems on its laboratory has seen no positive benefits to consumers as a result of
fume hood exhaust fans. electrical power de-regulation policies on the West Coast.
“After salaries, energy is the second largest expense item in the
Cooling Applications also Use Less Energy pharmaceutical research industry,” he said. “It is not unusual
Again, the facility manager cited some specifics. Since the com- in a facility such as ours to use 15% or more of the entire
pany is located in the Northeast United States, it experiences operating budget for energy, and this is not out of line for the
varying temperatures during the year. Conditioned industry,” he added. Consequently, he believes strongly in
makeup air is either cooled with fume hood exhaust air during selecting an engineering team when designing a new facility or
the cooling season or warmed during the heating season. The planning a major renovation which has direct experience in the
system is only usable when the outside air temperatures are pharmaceutical industry, particularly with regard to the ex-
below 40°F or above 80°F. “You need a big enough difference haust side as well as the energy reduction/consumption area.
between outside and inside air to make it practical,” he added Much of the statistics generated as a result of the energy
– Figure 4. With regard to cooling air in warmer temperatures, savings has been logged carefully by the facility manager, and
he pointed out that if outside air, at 90°F is brought back into are included here for reference. As he pointed out, “On my
the building and sent through the heat recovery system, the air screen I can actually see the temperature of the outside air,
temperature drop is typically 4°- 5°F. Again, he equates these observe the air going over the heat recovery coil, and then note
figures to a 3% drop in energy consumption for each 1°F drop the air temperature as it passes through.” He sees in real time
in air temperature. how much heat the system puts back into the makeup air
There are four different pharmaceutical research buildings before money has to be spent in heating it; the same is true on
at the company’s complex. At the Phase 1 building, individual the cooling side - Figures 2 and 3.
dedicated fans are used for exhausting individual laboratory Since he feels very strongly about energy costs, consump-
workstation fume hoods. The newly built Phase 4 building tion, and savings, the facility manager made it clear that the
incorporates the mixed flow exhaust systems with heat recov- recent energy de-regulation policies in California have not
ery capabilities – Figure 5. And, in the Phase 3 building, there resulted in reducing costs that were anticipated. “In other
are five laboratory workstations with associated fume hoods words, we are not going to de-regulate ourselves out of these
and dedicated fans for each of them. While he considers the high energy costs,” he added. Consequently, he believes that
Phase 1 and Phase 3 configurations less efficient by example pharmaceutical companies who are holding up energy conser-
of his success with heat recovery, he intends to change it with vation programs now because they believe de-regulation is
his “list of energy conservation strategies which I have gradual- “going to do it for them,” should perhaps begin looking at other
ly been putting in place.” approaches. He commented that “You can tell where the rest
PHARMACEUTICAL ENGINEERING • SEPTEMBER/OCTOBER 2001
Fume Hood Exhaust
OA Temp Space Hum.
16.0 °F 12.7 %RH
F+B % Open Command ON Smoke Status
OA Hum. HRC DAT
100.0 ON NORMAL
58.2 %RH 37.8 °F Status
O.A. S.A.
COOLING COIL
Pre-Filter
Status
16.0 °F 0.0 69.1
DIRTY
OA Temp % Closed DAT Temp/LL
After-Filter
Status H.W.S.
CLEAN
H.W.R. C.H.W.R. 47.9
HTG LOCKOUT 60.0 °F C.H.W.S. 58.4
Sup. Static Pressure 0.0%
CLG LOCKOUT 60.0 °F
% Open
NORMAL RESET SCHEDULE
AHU-1 Status
Space Discharge
Suction Static ON Temp. SetPoint
NORMAL 75.0 55.0
65.0 65.0
Phase IV AHU-1 Control Calculated SetPoint:
60.0 °F.
HTG S.P. - 3.0 °F.
Figure 3. System status monitor – outside air temperature at 16.0°F.
of the country is going to be in a year or two by looking at as defendants in major cases associated with employee illness
California, and the early results of de-regulation there have and IAQ. The company’s fume hood exhaust fans use mixed
not been good – in terms of cost and also in terms of reliability flow impeller technology to send the exhaust stream hundreds
of service.” He added that he would not “depend on de-regula- of feet into the air in a powerful vertical plume, mixing outside
tion to cut your energy bills; you have to work on the demand air with exhaust gases (dilution) to prevent re-entrainment as
side,” he concluded. well as eliminate odor problems. They also provide other
advantages, such as inherently lower energy consumption
Mixed Flow Impeller Technology Prevents over comparable centrifugal-type exhaust systems. With the
Re-Entrainment ability to pre-heat and pre-cool makeup air prior to its intro-
While roof exhaust re-entrainment can be a serious problem, duction into the building, the systems offer substantial energy
all of its negative implications may not be widely known. In saving benefits to pharmaceutical research and manufactur-
fact, not only can the health of building workers be affected by ing organizations.
exhaust reentering the building through windows, vents, air
intakes, and door openings (among other possibilities), but the Mixed Flow Technology Offers Performance and
legal consequences can extend well beyond their employers. Cost-Savings Advantages
For example, there have been cases where building owners, Mixed flow impeller-type roof exhaust systems operate on a
consulting engineers, Heating, Ventilation, and Air Condi- unique principle of diluting outside air with plenum exhaust
tioning (HVAC) contractors, and even architects were named air at high discharge velocities, sending a powerful vertical
SEPTEMBER/OCTOBER • 2001PHARMACEUTICAL ENGINEERING
Fume Hood Exhaust
PHASE IV EXPANSION N.C.
BACKFLOW TANK
PREVENTER
(P.O.S.)
TRI-STACK™ FAN
ET
3
ABOVE ROOFLINE DAMPER
EXPANSION
TANK
HEAT RECOVERY COIL HEAT RECOVERY COIL
TRI-STACK™ FANS
EXHAUST HRR
T-1
HEAT RECOVERY
COIL
HRU
1
HEAT EXCHANGER/TRI-STACK SYSTEM T-2
T-5
T-4
EXH.
EXH.
AIR AIR
Figure 4. Heat exchanger/mixed flow exhaust system.
Figure 5. Run-around-coil heat exchanger recovery flow diagram.
exhaust plume up to 350' high – Figure 6.
Because they introduce up to 170% of free outside air into
the exhaust stream, a substantially greater airflow is possible
for a given amount of exhaust without additional horsepower,
providing excellent dilution capabilities and greater effective
stack heights over conventional centrifugal fans.
These systems reduce noise, use less energy, and provide
enhanced performance with faster payback over conventional
centrifugal laboratory fume hood exhaust systems. With typi-
cal energy reduction of $.44 per cfm at $.10/kilowatt-hour,
these systems provide an approximate two-year ROI, there-
fore energy consumption is about 25% lower than with conven-
tional centrifugal fans – with substantially reduced noise
levels, particularly in the lower octave bands. They conform to
all applicable laboratory ventilation standards of ANSI/AIHA
Z9.5 as well as ASHRAE 110 and NFPA 45, and are listed with
Underwriters Laboratory under UL 705.
The systems are designed to operate continuously without
maintenance for years under normal conditions - direct drive
motors have lifetimes of 200,000-hours. Non-stall characteris-
tics of the system’s mixed flow wheels permit variable fre-
quency drives to be used for added Variable Air Volume (VAV)
savings, built-in redundancy, and design flexibility.
Virtually maintenance free operation (there are no belts,
elbows, flex connectors, or spring vibration isolators to main-
tain) eliminates the need for expensive penthouses to protect
Figure 6.Typical mixed flow impeller system. maintenance personnel under adverse conditions. Conse-
PHARMACEUTICAL ENGINEERING • SEPTEMBER/OCTOBER 2001
Fume Hood Exhaust
PHASE IV
PS
3/4" C.W.
MAKE–UP
3/4"
AS
3
P
5 AIR SEPARATOR
HRR
CT
R
BYPASS
(V-2)
CHEMICAL
CT HRU SHOT FEEDER
R 1 SEE DWG. H-16
(STANDBY) FOR AHU CONTROL
T-3
HRS
(V-1) N.O.
HRU
1 N
AHU
INTAKE
RUN–AROUND–COIL HEAT RECOVERY FLOW DIAGRAM
quently, additional savings of several hundreds of thousands References
of dollars are realized in a typical installation. 1. Neurogen Corp., Branford, CT.
Mixed flow impeller systems are available with a variety of 2. Bill Waldron.
accessories that add value, reduce noise, or lower energy costs
substantially. For example, accessory heat exchanger glycol/ About the Author
water filled coils for use in 100% conditioned makeup air Paul A. Tetley is Vice President and General Manager of
facilities add exhaust heat to intake ventilation air to save thou- Strobic Air Corp., a subsidiary of Met-Pro Corp. Since joining
sands (or hundreds of thousands) of dollars in energy. the company in 1989 as engineering production manager, he
has designed and/or invented many innovative Tri-Stack fan
Conclusion systems, an acoustical silencer nozzle, and a unique multi-fan
Recovering ambient heat prior to exhausting it outside the plenum system.
building is generally only cost-effective when 100% condi- Strobic Air Corp., 160 Cassell Road, Harleysville, PA 19438,
tioned makeup air is required as in the case of this pharmaceu- (215) 723-4700, [email protected].
tical manufacturer. Because there are so many variables
between facilities – including physical layouts, equipment,
heating/cooling systems, etc. – it makes sense to look into other
methods of heat recovery and/or heat efficiency as well. And,
because climate is a key factor in this equation, a full year’s
outside temperatures should be considered to help make a
better determination as to what might be suitable. For labora-
tory environments, another energy conservation approach
would be automated control of laboratory workstation fume
hood exhaust rates based upon occupancy sensing.
SEPTEMBER/OCTOBER • 2001PHARMACEUTICAL ENGINEERING
For pollution abatement and
Strobic Air odor control (quietly)...
TRI-STACK
™
Tall stacks are good,
ROOF EXHAUST SYSTEMS
but Tri-Stacks are best! ™
Tri-Stack systems are ideal for
new construction and direct
replacement of conventional
centrifugal exhaust fans. Tri-Stack
systems feature unique design,
high efficiency operation for lower
system static pressure, reduced
energy costs and provide two-year
payback in most installations.
Tri-Stacks are also virtually
maintenance free, operating
continuously – without periodic
maintenance – for years under
normal conditions. Low profile, quiet solutions for roof exhaust
problems for laboratory workstations
Contact us today for full and industrial processing
technical details or to discuss
your application. Prevent re-entrainment
®
Eliminate odor
First we invented the technology.
Then we perfected it. Reduce noise at the property line
Strobic Air Comply with architectural/aesthetic ordinances
Corporation Lower energy costs
160 Cassell Road, P.O. Box 144
Harleysville, PA 19438
Tel: 1-215-723-4700 For design/applications tips, visit our web site: www.strobicair.com
Toll Free: 1-800-SAC-FANS
Fax: 1-215-723-7401 www.met-pro.com/strobic.html • E-mail: [email protected]
