Overview Contents

Overview Contents
Section
Page
1. New Cabinet Benefits...................................................2
2. Fundamentals.............................................................. 3-5
3. Application Data.......................................................... 6-7
4. Combined Efficiencies..................................................8
5. Warranty Information....................................................9
6. Mating Options.......................................................... 10-14
7. Combo-curb Flow Options....................................... 15-17
Benefits of the new MicroMetl ERV
1.
Cabinet airflows range from 200 – 30,000 cfm
2.
Cabinets now have multiple standard indoor & outdoor configurations
a.
Down
b.
Horizontal
c.
HSVR
d.
Top duct connections
3.
Ease of set-up
a.
No belts & pulleys to adjust
b.
Backlit LCD display with pushbutton & potentiometer operator interface
4.
Units come standard with a VFD (Except EVA cabinet).
5.
Smaller footprint
6.
Less Weight
7.
High efficiency motors E.C. motors
8.
High efficiency backward incline fans
9.
High static fan options
10.
Multiple mating options
a.
Stand alone units
b.
Combination curbs
c.
Transitions
d.
Drop in damper boxes
e.
Direct mated units
11.
Ability to select any airflow and wheel effectiveness
Guide to Ventilation
The Fundamentals
Why Ventilation?
The HVAC community plays a vital role in providing
healthful indoor environments in which to live, learn,
work, and play. With half of all illnesses attributable to
indoor airborne contaminants, the EPA has declared
indoor air quality a public health priority. Ventilation with
outdoor air is the only strategy that can simultaneously
reduce the levels of all indoor pollutants. This strategy,
in general accordance with the Dilution Principle, is
shown in the illustration below.
Energy recovery ventilation reduces the load on the
system due to outdoor air by taking advantage of the
work that has already been done to heat, cool, humidify
or dehumidify the space. Instead of exhausting building energy to the outside, it is temporarily captured on
the surfaces of the enthalpy wheel heat exchanger and
then released to pre-heat, pre-cool, humidify or dehumidify the incoming air. Enthalpy wheels do this with
exceptional efficiency and are the leading technology
for achieving energy conservation while ventilating for
health and comfort.
The Power of Enthalpy
The next three figures illustrate the power of enthalpy
exchange. The first chart shows the result of just adding
the required load from increased ventilation to the normal air conditioning process line.
Each doubling of the ventilation rate results in a 50%
reduction in the concentration of all constant source air
pollutants evenly mixed within the space. At 1.0 ACH,
pollutant concentrations are reduced by a factor of 5.
National, state and local codes mandate minimum outdoor air ventilation rates based on ASHRAE Standard
62.1, Ventilation for Acceptable Indoor Air Quality. The
challenge is to introduce the outdoor air at the levels
required by the codes while maintaining indoor comfort
and conserving energy.
The chart below shows the new process line when using
enthalpy recovery. As one can see, the cooling load
(work) saved is a direct result of the difference in the two
enthalpies.
Why Energy Recovery Ventilation?
Building code requirements for increasing outdoor air
ventilation rates have placed new demands on HVAC
equipment and on building operating budgets. At the
same time, new refrigerants being deployed to lower
atmospheric ozone concerns have reduced equipment
capacity and global warming is threatening to place even
greater restrictions on our use of energy.
As shown below, with the use of an enthalpy recovery device,
the conditions entering the coil or the building are in a more
advantageous area of the psychrometric chart, and actually
reduce the workload on the coil or the system.
Application Considerations
IndustrialProcesses
PrintShops
•
•
•
•
•
•
•
IceRinks
•
•
•
Hospitals
•
•
•
•
•
Cross-transferofpollutantsfromexhausttosupplyair.
Operationaltemperaturerangerequired.
Abilitytocleanthepollutantsfromtheexhaustairstreamthatdepositonthe
wheel.
Donotuseenergyrecoveryfromfumehoodexhaust.
Donotuseenergyrecoveryontheairfromtheprintheadexhaust.
AnERVmayrequiresupplementaryheatinganddehumidificationtocontrolthe
spacehumiditytotolerancesrequiredforpaperbasedproducts.
Regularcleaningtokeeplatentperformanceatfactoryoriginallevelsis
suggested.
Ventilationairmustbedriedandpretreatedtokeepindoorrelativehumidity
belowthedewpointsaticelevelsontherink.
Enthalpywheelsarerecommendedforcontrollingtheintroductionofhumidity
belowthedewpointsaticelevelsontherink.
Ventilationcanbestagedforoccupancy,butallowancemustbemadeforthe
operationofgas-firedZamboniicemachinesduringlowoccupancy.
Frostcontrolisrarelyrequiredduetothedrynatureofexhaustair.
Enthalpyrecoverywheelsareacceptableforventilationincommonuseareas
suchaspatientrooms,waitingareas,andhallways.
Operatingroomsandlabsmayneedtoavoidthepossibilityofeventheslightest
cross-transferofexhausttosupply.Mosthospitalventilationcodesrequirefinal
filtersandseparationofintakeandexhaust.
Wheelsmustberegularlycleanedandmaintainedtoassurethehighestsupply
airquality.
Ventilationisa24/7requirement,soprovisionforlowtemperatureoperation
(frostcontrol)mustbeconsideredincoldclimates.
Application Considerations (continued)
NursingHomes
•
•
•
•
CorrectionalFacilities
•
•
•
ToiletExhaust
•
•
•
Hospitality/Smoking
•
•
•
Retail
•
•
General
•
•
•
•
•
•
•
Odorgenerationmandatesventilationratesatorabovethe
minimumslistedinASHRAEStandard62.1.
Enthalpyrecoveryassistswithhumiditycontrol,whichis
importantforoccupantcomfortandhealth.
Frostcontrolisrequiredinmanycoldclimates.
Speciallaboratoryorinfectiousdiseaseareasshouldhave
dedicatedexhausts.
Odorgenerationmandatesventilationratesatorabovethe
minimumslistedinASHRAEStandard62.1.
24/7operationrequireslowtemperature(frost)operational
controlsinmanycoldclimates.
Thepossibleneedtocontrolinfectiousdisease,particularly
tuberculosis,requiresapplicationscareandmayrequirefinal
filters.
Odorcontrolisrarelyanissuewhentoiletexhaustisprovidedat
ASHRAEStandard62.1.Table2minimums.Consider
additionalexhausttobalanceflowswhenusingenergyrecovery.
Make-upairfortoiletexhaustisgenerallyprovidedbytransferair
fromsurroundingspaces.
Themixingoftoiletexhaustwithspaceventilationexhaustis
acceptableforsystemswherecross-transferislimitedto10%or
lessoftheexhaustairsteam.
Controlandseparationofsmokingandnon-smokingareas
presentsdesignchallengesasdoeskitchenventilationfrom
grills,fryers,andovens.
Wheresmokingisallowedandexhaustedthroughanenthalpy
recoverywheel,thoroughcleaningevery90daysishighly
recommendedtoavoidbuildupoftarsandnicotineonthe
surfaceofthewheel.
Supplyaircomingthroughawheelthathassmokingroom
exhaustmustalwaysbesuppliedbacktothesmokingspace.It
shouldnotbesuppliedtonon-smokingareasduetoconcernsfor
odortransfer.Spaceconditioningshouldbeprovided
separately,aswell.
Retailventilationisimportanttominimizetheconcentrationof
chemicalsinthespaceduetoclothingdyes,paint,and
formaldehydefromproductsandfurnishings.
Significantsavingsinventilationcostsareavailableduetolong
hoursofoperation.
Frostcontrolshouldbeconsideredincolderclimates.
Observecareinlocatingthesupplyairintakeoftheenergy
recoveryventilator.Avoidthepossibilityofdirecttransferof
exhaustairbackintothespace.
Avoidplacingplumbingandbathroomventsnearsupplyair
intakes.
Avoidplacingkitchenexhaustnearoutdoorairsupplyintakes.
Neveruserotaryenthalpyrecoveryoncontaminatedexhausts
fromlaboratoryhoods.
Neveruserotaryenthalpywheelsonpaintboothexhaust.
Neveruserotaryenthalpywheelsondirectexhaustof
automobileengines,ordieselexhausts.
Application Data
All ventilated spaces are good candidates for energy recovery systems. The best applications
are when a large amount of outside air is required for a space that has a low internal load. This is
true because most outside air loads are latent which requires the up sizing of the unit to meet both
internal and ventilation loads. The advantages of the ERV unit are the ability to reduce the size of
the HVAC unit, to provide better humidity levels and to provide a stable, tempered space. Examples of ERV applications are classrooms, churches, conference rooms, game rooms, auditoriums, movie theaters, day care centers, nursing homes, funeral homes, dormitories, and clinics. Retrofits of existing systems to handle outside air without changing the HVAC unit are excellent
applications.
Other examples are bars, restaurants, casino/game rooms, barber-beauty shops, bingo halls,
locker rooms, recreational facilities and health clubs. Animal shelters such as veterinary clinics
and kennels have been very successful implementations. Retail spaces and manufacturing facilities are also good applications.
If the outside air requirement is greater than 10% of the HVAC unit’s supply air rating: an ERV
unit should be considered to enhance the comfort of the occupants and reduce the tonnage of the
HVAC unit. The MicroMetl/Airxchange selection program offers a quick, simple overview of the
advantages and payback of an ERV system. The following pages contain a sample application and examples of the MicroMetl/Airxchange
selection program for each cabinet size. The weather data was for Indianapolis, Indiana 1%
ASHRAE weather conditions.
Choosing the proper airflow is essential. The MicroMetl part numbers include the airflow range
that the cabinet blowers are manufactured to operate within. This airflow range can be determined from the middle 4 digits of the part number: digits 1 and 2 (multiplied by 100) indicate the
minimum airflow while digits 3 and 4 indicate the maximum airflow. For example, an ERVA-1014D43 unit has an airflow range of 1000 cfm to 1400 cfm. Please note that all cabinets can be used in lower airflow applications than the part number calls
out. This option can be used for high static applications. Although performance is optimized
at equal exhaust and supply airflow rates, the MicroMetl/Airxchange selection program and the
ERV unit can be used with unequal airflow amounts. You must size the unit for the largest airflow
amount. The lower airflow cannot be less than 50% of the higher airflow.
Application Data - Sample
The following is a typical application for an ERV unit.
A consulting engineering firm has specified an HVAC system requiring 1000 cfm of outside air and
90,000 Btu/hr cooling load. This system as specified would require a 12 1/2 ton HVAC unit. In
order to improve the efficiency of the rooftop unit, an ERV will be considered.
1.
2.
3.
4.
5.
6.
7.
8.
Obtain the load breakdown from the design engineer: ventilation load, sensible load
due to occupancy and building orientation, latent load due to occupancy and building
orientation. If this information is not available, enter the building envelope into the HVAC sizing program, Block Load or HAPS.
Analyze the building system as specified by the design engineer with the ventilation load.
Delete the ventilation load from the analysis. Re-run.
Run the MicroMetl/Airxchange selection program specifying an ERVA-1014 ERV unit at 1000 cfm.
The MicroMetl/Airxchange selection specifies that the outside air load is 43,177 Btu/hr with
out the ERV unit. The ERV unit relieves 28,828 Btu/hr. Resulting in a HVAC outside air load of only 14,357 Btu/hr.
Add the remaining outside air loads (14,357 Btu/hr) to the results of the space load analysis (90,000 Btu/hr - step 3).
These are the new HVAC unit load factors. Specify the HVAC unit based upon this loading. For this example, the new HVAC load is 104,357 Btu/hr.
If required, the MicroMetl/Airxchange selection contains an hourly bin analysis option that will allow you to provide operational data.
The ERV unit can be coupled to the HVAC unit via a MicroMetl provided transition or the ERV unit
can be used as a stand-alone unit. A coupled HVAC/ERV unit is preferred because there are no
additional roof penetrations needed and no additional duct work required. A stand-alone unit is
available if space is a factor or if the fresh air needs to be directed into a dedicated area. When
using the stand-alone option, it is recommended that the wheel by-pass option (ERV-OPT-036) be
used as well to provide “free cooling” if conditions will allow.
CombinedEfficiency(CEF)
The Air-Conditioning & Refrigeration Institute (ARI) has published "Guideline V" to establish a method of calculating the
energy efficiency of applied Energy Recovery Ventilation components and of heating, ventilating, and/or air-conditioning systems
utilizing such components at selected operating conditions. It also provides guidance on proper sizing of cooling and heating equipment
when such energy recovery components are applied.
The formula used in the Combined Efficiency (CEF) calculation can be found in Guideline V, or can be calculated using the MicroMetl /
Airxchange selection and sizing software.
Listed below are some examples of the Combined Efficiencies of using a Carrier rooftop unit with a MicroMetl Energy Recovery unit.
CombinedHVAC/ERVEfficiencyExamples
HVACEER
MMCERVUnit
Outside
Air
Percent
ofOA
48HJ006
.
ERVA-1014
EVCG
1,000
50%
14.93
14.94
15.88
14.53
48PG006
12.0
ERVA-1014
1,000
50%
16.02
16.03
17.04
15.59
48HJ012
11.0
ERVB-2025
2,000
50%
14.80
14.82
15.74
14.47
48PG012
12.0
ERVB-2025
2,000
50%
16.01
16.03
17.03
15.65
48HJ017
10.5
ERVB-2532
3,000
50%
13.56
13.59
14.35
13.32
48PG016
.
ERVB-2532
3,000
50%
14.60
14.62
15.45
14.34
48PG024
.
ERVC-3650
4,000
50%
15.75
15.77
16.77
15.39
HVACUnit
EVCG
EVEF
EVEF
EVEG
EVEG
EVHF
*************CombinedEfficiency(CEF)********************
Indianapolis
Atlanta
Houston
Phoenix
MicroMetl
EVCG
Carrier
48PG 006 HVAC
RER FORMULA=
EER FORMULA=
Net Conditioning Recovered
Net Cooling Capacity
Total Electric Power Consumed
Total Electric Power Consumed
RER= 63.3
EER= 12.0
2003
GUIDELINE for
17.04 Combined
Efficiency (CEF)
Calculating the
efficiency of
energy recovery
ventilation and
it’s effect on
efficiency and
sizing of building
HVAC systems.
Guideline V
100 N. FAIRFAX DR., SUITE 200 • ARLINGTON VA 22203
MicroMetl’s ERV Warranty Plan
General Warranty Statement:
The ERV rotary cassette wheel used in MicroMetl’s ERV units are warranted to be free from
defects in material and workmanship under normal use and service for a period of 5 years for all
parts and components.
MicroMetl warrants for two years all Energy Recovery unit products (other than the ERV wheel)
to be free from defects in design, material, and workmanship under normal use and service.
This warranty applies to blowers, blower motors, and all other ERV components (other than ERV
wheel). Our obligation shall be limited to repairing or replacing defective components or assemblies., as our inspection determines to be defective. MicroMetl will allow freight charges, however
air freight charges are not included.
General Conditions:
All warranty periods commence at date of original installation, or 6 months after date of shipment,
if earlier. This warranty does not cover the cost of labor for any adjustments or service calls, nor does it
include the cost of labor for replacing defective parts or components. This warranty does not apply
if the ERV unit or wheel has been subject to misuse, abuse, neglect, accidental damage, or alteration. This warranty applies only to parts supplied or designated by MicroMetl.
This express warranty is in lieu of all other warranties, expressed or implied, including implied
warranties of merchantability or fitness for a particular purpose, which are hereby excluded. MicroMetl shall not be liable for special, incidental, or consequential damages or losses from any
cause whatsoever including, without limitation, loss of use, commercial profits, or customer goodwill, and any other claims based on contract or tort, whether or not arising from MicroMetl’s negligence.
Extended Warranties:
MicroMetl offers extended ERV warranties covering defects in material and workmanship under
normal use and service. Contact factory for details.
ERV Mating Options
MicroMetl has (4) different means of mating an ERV to a rooftop unit. These options are in addition to the stand alone format. These options are as follows:
1. Combination Curb
2. Transition
3. Drop-in Damper Box
4. Direct Mated Unit
We will describe and talk about each of these options individually and point out the benefits and
disadvantages of each in the following pages.
10
ERV Mating Options - Combination Curb
The combo-curb is a single curb that holds both the HVAC unit and the ERV on the same curb. The transition of the air happens in transitions in the curb.
Benefits:
• Ease of set-up and installation at the jobsite. You only have to set 1 curb as opposed to
setting 2 curbs and a transition. You will always have the proper distance set
between the HVAC unit and the ERV.
•The electrical contractor can run a single disconnect to power both units since they are
sitting on a common curb.
• We can mate any ERV to HVAC unit that has a vertical return.
• Units are designed to allow the standard HVAC economizers and powered exhaust to be
installed in the units.
Fresh Air In
MicroMetl ERV Unit
HVAC Unit
Exhaust Air Out
Combo-Curb
Return Air From Building
Conditioned Air To Building
11
ERV Mating Options - Transition
Transitions are used to tie to horizontal return HVAC units. We are providing the ductwork that tie
into the horizontal return all the way back to the transition where the ERV ties into the ductwork. The contractor would then tie into our transition the same way he would tie into the return of the
HVAC unit. Both the HVAC and the ERV will still need their own curbs.
Benefits:
• Units are designed to allow the standard HVAC economizers and powered exhaust to be
installed in the units.
• Units are designed to prevent short cycling.
• We can mate any ERV to HVAC unit that has a horizontal return.
12
ERV Mating Options - Drop-in Damper Box
Drop-in damper boxes can be used in place of the combination curb. That means this only works
with a vertical return HVAC unit. This damper box is the box that is in place in the combination
curb to help route the air through the curbs and keep the supply air from short cycling out of the
return. The damper box would be installed in the HVAC curb return chamber. The contractor would
then make two duct runs under the roof. One would be from the supply side of the ERV to the
supply side of the damper box. The second would be from the return side of the ERV to the return
side of the damper box. To control the static pressure drop through the ducts, you can only run
100’ equivalent duct per run between the ERV and the damper box. Any more than this will start to
provide less airflow through the ERV. This configuration allows for the ERV to be laid out on any
side of the HVAC unit.
Benefits:
• Units are designed to allow the standard HVAC economizers and powered exhaust to be
installed in the units.
• Units are designed to prevent short cycling.
• We can mate any ERV to HVAC unit that has a vertical return.
• This configuration allows for the ERV to be put on any side of the HVAC unit.
13
ERV Mating Options - Direct Mated Units
Direct mated units are units that bolt directly on to the HVAC unit without the using a curb or
transition. The direct mated units we are talking about here are units that are field installed only.
This unit is bolted onto the HVAC unit at the economizer opening. The units can come as an ERV
by itself (no economizer) or be equipped with an economizer and additional power exhaust. The
direct mated units will only work with the economizer that comes with the ERV. If an economizer
is already installed in the HVAC unit, it will have to be removed before the ERV is installed. These
units have fewer options than the regular ERV’s. To install the unit, the contractor would install the
damper section in the rooftop unit, plug into the economizer plug, bolt the unit to the outside of the
HVAC unit, and run power to the ERV.
Benefits:
• This is the most cost effective means of providing an ERV with a rooftop (no roof curb or
transition needed for the ERV).
• It is easy to install.
• Has an optional economizer with power exhaust.
14
Combo-curb Flow Options
ERV is providing 100% outside air to the HVAC Unit.
ERV is providing less than 100% outside air.
15
Combo-curb Flow Options cont.
HVAC Unit is in the unoccupied mode. No outside air.
HVAC Unit is in free cooling. Economizer is open. Exhaust air through economizer or
power exhaust.
16
Combo-curb Flow Options cont.
HVAC Unit is in free cooling. Economizer is open. Exhaust air is through the ERV.
17