[Equest-users] design flow input vs. SV-A supply flow reporting
Carol Gardner
cmg750 at gmail.com
Fri Oct 8 10:12:38 PDT 2010
Here's the help manual write up on this. Lengthy but invauable.
Volume 4: Libraries & Reports <volume4librariesreports.htm> >
Reports<reports.htm>>
SYSTEM-REPORT <systemreport.htm>
SV-A System Design Parameters for <system name>
This report echoes your input to the program for each system as interpreted
by the SYSTEMS design routines. See “DESIGN-DAY Command” in the Topics
Manual. The report is divided into three sections: System-Level Design
Values, Fan Design Values and Zone-Level Design Values.
For systems having mixing sections (dual-duct and multizone systems) an
additional section appears detailing the cold duct, hot duct, and total
zonal air flows, as well as the minimum air flow ratios for these
quantities.
Note: the quantities in this report have been adjusted for altitude even
though DOE-2 requires that any flows you enter in SYSTEMS be at sea level.
Design-day sizing of VAV system Show All
Reports
REPORT- SV-A System Design Parameters for
SYST-1 WEATHER FILE- TRY
CHICAGO
---------------------------------------------------------------------------------------------------------------------------------
FLOOR OUTSIDE
COOLING HEATING COOLING HEATING HEAT PUMP
SYSTEM ALTITUDE AREA MAX AIR CAPACITY
SENSIBLE CAPACITY EIR EIR SUPP-HEAT
TYPE FACTOR (SQFT ) PEOPLE RATIO (KBTU/HR) (SHR)
(KBTU/HR) (BTU/BTU) (BTU/BTU) (KBTU/HR)
VAVS 1.020 5000.0 52. 0.179 241.081
0.662 -50.000 0.000 0.000 0.000
DIVERSITY POWER FAN STATIC TOTAL
MECH MAX FAN MIN FAN
FAN CAPACITY FACTOR DEMAND DELTA-T PRESSURE EFF
EFF FAN FAN RATIO RATIO
TYPE (CFM ) (FRAC) (KW) (F) (IN-WATER) (FRAC)
(FRAC) PLACEMENT CONTROL (FRAC) (FRAC)
SUPPLY 5924. 1.00 6.817 3.63 5.5 0.55
0.72 DRAW-THRU SPEED 1.10 0.30
SUPPLY EXHAUST MINIMUM OUTSIDE
COOLING EXTRACTION HEATING ADDITION
ZONE FLOW FLOW FAN FLOW AIR FLOW
CAPACITY SENSIBLE RATE CAPACITY RATE ZONE
NAME (CFM ) (CFM ) (KW) (FRAC) (CFM )
(KBTU/HR) (FRAC) (KBTU/HR) (KBTU/HR) (KBTU/HR) MULT
ZONE1-1 1623. 0. 0.000 0.300
224. 0.00 0.00 32.64 -87.91 -54.50 1.
ZONE2-1 784. 0. 0.000 0.300
102. 0.00 0.00 15.78 -42.49 -26.34 1.
ZONE3-1 1207. 0. 0.000 0.300
224. 0.00 0.00 24.28 -65.40 -40.55 1.
ZONE4-1 765. 0. 0.000 0.300
102. 0.00 0.00 15.40 -41.46 -25.71 1.
ZONE5-1 1545. 0. 0.000 0.300
408. 0.00 0.00 31.08 -83.72 -51.91 1.
PLENUM-1-Z 0. 0. 0.000 0.000
0. 0.00 0.00 0.00 0.00 0.00 1.
*System-Level Design Values*
SYSTEM TYPE
is the code-word identifying the type of system.
ALTITUDE FACTOR
is the altitude adjustment factor for air flows; it multiplies air flows at
sea level to get air flows at the actual altitude of the building.
FLOOR AREA
is the total floor area of all zones served by the system that have
ZONE-TYPE = CONDITIONED or UNCONDITIONED, or, for ZONE-TYPE = PLENUM, that
have non-zero occupancy.
MAX PEOPLE
is the maximum number of people in all of the zones served by the system
that have ZONE-TYPE = CONDITIONED or UNCONDITIONED, or, for ZONE-TYPE =
PLENUM, that have non-zero occupancy. The maximum number of people in a zone
is determined by the NUMBER-OF-PEOPLE or AREA/PERSON keywords in the SPACE
command; any variation in occupancy resulting from PEOPLE-SCHEDULE is
ignored in calculating MAX PEOPLE.
OUTSIDE AIR RATIO
is the ratio of outside air flow to supply air flow at design conditions for
central systems. Its value is either the user input value of
MIN-OUTSIDE-AIR or is calculated by SYSTEMS from the ventilation or exhaust
input at the zone level divided by the supply fan flow (as listed in the Fan
Design Values section, below) . This is a design quantity and so does not
reflect values entered through the MIN-AIR-SCH keyword. For zonal systems,
this value will be zero.
When OUTSIDE AIR RATIO is determined from zone ventilation rates, it is the
sum of the values under OUTSIDE AIR FLOW (in the Zone-Level Design Values
section, below) divided by the supply fan flow. This outside air ratio is
what the program will use as the minimum outside air ratio. It is assumed
that the outside air is brought in at the main system fan and is distributed
to the individual zones in proportion to the supply air to each zone.
Note: The SYSTEMS design routine does not examine the values entered in
schedules. Consequently, if you specify the outside air ratio through
MIN-AIR-SCH but want SYSTEMS to size the equipment, you should also specify
MIN-OUTSIDE-AIR.
COOLING CAPACITY
is either the value you enter for the keyword COOLING-CAPACITY at the system
level or is computed by SYSTEMS from the peak (sensible plus latent) cooling
load.
SENSIBLE (SHR)
is the sensible heat ratio, i.e., the fraction of the total cooling capacity
that is sensible cooling capacity at the peak or design condition. If you
have not entered COOL-SH-CAP at the system level for a central system, this
value is calculated from a simulation of the conditions at peak loads.
HEATING CAPACITY
is the maximum value for heating. It reflects either the user input or a
calculation from peak loads. Like COOLING CAPACITY, this value will be zero
for zonal systems, where the capacity is shown at the zone level.
COOLING EIR
is the electric input ratios for cooling. Values are taken from user input
or are default values.
HEATING EIR
is the electric input ratios for heating. Values are taken from user input
or are default values.
HEAT PUMP SUPP-HEAT
is the heat pump supplemental heating capacity.
*Fan Design Values *
This section gives the characteristics of the system supply and return fans.
Given for each fan are: type, capacity, rated capacity, diversity factor
(capacity*[MAX-FAN-RATIO] / [sum of zone air flows]), power demand, fan
temperature rise, static pressure, supply efficiency, supply mechanical
efficiency, fan placement, type of fan control, and the maximum and minimum
fan ratios.
Note that the static pressure may have a value of zero. This simply means
that the static pressure was not specified and was not used to calculate fan
power consumption.
*Zone-Level Design Values*
The following quantities apply to the base zone and have not been multiplied
by the number of identical zones (as given by the product of MULTIPLIER and
FLOOR-MULTIPLIER).
SUPPLY FLOW
is the calculated or user-specified supply flow for each zone. Only if you
have specified a value for the ASSIGNED-FLOW keyword in the ZONE-AIR command
will the value here correspond to your input. The ZONE keywords
AIR-CHANGES/HR and FLOW/AREA will be accepted by SYSTEMS only if they are
consistent with the user-supplied HEATING-CAPACITY and COOLING-CAPACITY and
are equivalent to a flow larger than that of the exhaust from or the
ventilation to the zone. The ALTITUDE FACTOR will be applied.
EXHAUST FLOW
is the airflow exhausted directly from the zone via an exhaust fan.
FAN
is the total of the zone supply and exhaust fan electrical consumption at
design conditions. This is zero in the example because there are no zone
fans.
MINIMUM FLOW
reflects the your input for MIN-FLOW-RATIO, unless that input is in conflict
with exhaust or ventilation requirements. In the absence of user input,
SYSTEMS will calculate the minimum flow ratio for VAV systems from the
minimum flow needed to meet the minimum ventilation requirements and the
required heating capacity.
OUTSIDE AIR FLOW
reflects the user-specified outside air quantity entered at the zone level.
If OUTSIDE-AIR-FLOW is specified, its value is multiplied by the ALTITUDE
FACTOR and reported here. Otherwise the reported value is the maximum of
the flow-equivalent values of OA-CHANGES and OA-FLOW/PER, multiplied by
ALTITUDE FACTOR. For the actual amount of outside air delivered to the zone
for central systems, see OUTSIDE AIR RATIO above.
COOLING CAPACITY
will be zero at the zone level for central systems. For zonal systems it
will either be the value you specify for COOLING-CAPACITY or it will be
calculated by SYSTEMS to meet the peak loads at the rated conditions for HP,
PTAC, and FC systems or at any conditions for IU systems. This is done
similarly for HEATING CAPACITY for the above-mentioned systems and for UVT
and UHT systems.
SENSIBLE
is the cooling sensible heat ratio for zonal systems.
EXTRACTION RATE
is the cooling extraction rate at design conditions. This is not the value
used in the simulation; that value is recalculated hourly and depends on the
loads, the conditions, the thermostat type and the thermostat throttling
range. ADDITION RATE (heating) is treated similarly.
HEATING CAPACITY
is the design capacity of the zonal heating equipment, if any.
ZONE MULT
is the user-specified number of identical zones (product of MULTIPLIER and
FLOOR-MULTIPLIER for the zone).
For systems having mixing sections (dual-duct and multizone systems), an
additional section details the cold duct, hot duct and total zonal air
flows, as well as the minimum air flow ratios for these quantities.
On Fri, Oct 8, 2010 at 8:06 AM, Paul Diglio <paul.diglio at sbcglobal.net>wrote:
> Carol:
>
> I am having the same problem with airflow almost double from what I
> specified. I tried the altitude correction and that did not help.
>
> Does the zone air flow and exhaust rate take preference over the fan flow
> parameters?
>
> Thank you,
>
> Paul Diglio
>
>
> ------------------------------
> *From:* Carol Gardner <cmg750 at gmail.com>
> *To:* cstalberg at naturalintelligence.us
> *Cc:* equest-users at lists.onebuilding.org
> *Sent:* Fri, October 8, 2010 9:33:46 AM
> *Subject:* Re: [Equest-users] design flow input vs. SV-A supply flow
> reporting
>
> Not stupid at all, If you have your altitude set to anything but 0 eQUEST
> will adjust your cfm accordingly. I always go in and set it manually to
> zero. I think it reads what it is off the weather file.
>
> Carol
>
> On Fri, Oct 8, 2010 at 6:54 AM, Christian Stalberg <
> cstalberg at naturalintelligence.us> wrote:
>
>> They say no question is a stupid question.
>>
>> Why is my zone level supply flow cfm reported value in the SV-A report
>> higher than my overall design flow (ASSIGNED-FLOW) value? The
>> system sizing ratio is set at 1.00 (default).
>>
>> Thanks in advance.
>>
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>>
>
>
> --
> Carol Gardner PE
>
--
Carol Gardner PE
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