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HAP e-Help 004 V4.20a October 27, 2005

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Transfer Function Methodology (TFM)

The Transfer Function Methodology (TFM) is a dynamic means of accounting

for heat transfer. Although there are other methods of accounting for heat
transfer, Carrier’s HAP program utilizes TFM in its calculations because it
extends the analysis to account for specific system behavior to control the air
temperature in the thermostat zones.

This article will review the calculation methodology of TFM to assist in

interpreting the results of the HAP program. However, this article will not
discuss the actual equations and formulas used. Such specific information
can be found in the ASHRAE Fundamentals Handbook and in the HAP Help
System, Chapter 27: Load Calculations. See Figure 1.

HAP e-Help has noticed that users of HAP have encountered two issues that
are preventing efficient use of the program. These issues are:

• Consideration of load estimating as a steady-state, instantaneous

occurrence rather than a dynamic process

• Expectation of results based on previous experience with other load Figure 1 - HAP Online Help
estimating programs that do not utilize TFM, especially those using
simplifications to allow manual load calculations

TFM is a derivative of the Heat Balance Method. Calculation shortcuts and assumptions are used to reduce the volume and
detail of required input, and to speed up calculations. (See Section 27.2 in the HAP Online Help System.) Reduced input and
faster calculations make this method more efficient. For example, the coefficients in Transfer Function equations are derived
directly from a Heat Balance analysis. The Heat Balance equations are used once to derive Transfer Function coefficients,
and the coefficients are used repeatedly to quickly calculate
loads. (TFM does not use U-values for walls and roofs.)

Conduction, convection, and radiation are the main drivers of

heat transfer to or from the air in the room. The resulting
room air temperature is calculated. The loads reported in
HAP indicate how much cooling or heating is needed to
maintain the room temperature within the throttling range.
What is described below may be a new way of considering
the effects of heat gain and cooling load compared to
previous hand calculation methods adopted in the HVAC
engineering community. The methods used by HAP align with
ASHRAE calculation methodology.

Figure 2 - Wall Heat Gain Example

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Transfer Function Methodology (TFM)

The dynamics of heat gain over time are best described graphically. Because an east-facing wall (See Figure 2) is used in the
example, the sol-air temperature curve shows the effects of large morning heat gains due to solar radiation and smaller
afternoon heat gains due to reduced sunshine but warmer outdoor air temperatures. The heat gain curve reveals the transient
heat transfer processes involved. While the sol-air temperatures peak at 8 a.m., the interior wall heat gains for this medium-
weight wall do not peak until 2 p.m. This reveals the time it takes for heat to be conducted through this specific type of wall
construction.

Radiation heat gains from sources such as solar, lights and even people take time to become a load. The radiant heat must
first heat up the building and contents and then be conducted and released over time to the room air by convection
processes. This causes a delay between the time a heat gain occurs and the time its full effects as a cooling load appear.

Figure 3 shows the load and heat gains

for lights turned on for six hours. Note that
the loads are smaller than the heat gains
while the lights are on. This is because a
large portion of the heat gain is thermal
radiation.

Also note that cooling loads continue after

lights are turned off and the heat gains
cease. Again, this is due to the radiant
heat and the heat storage effects. When
the lights are turned off, some radiated
heat from the previous six hours is still
stored in the room mass and continues to
be convected to room air over time.

Figure 3 - Lighting Heat Gain Example

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Transfer Function Methodology (TFM)

Figure 4 illustrates that the Transfer Function Method models the transient build-up and discharge of heat in a building.

The convection process is governed by the temperature

difference between the mass and the room air. Convection
decreases as the room air temperature rises and increases
as the room air temperature decreases. Hand calculation
methods assume a constant room air temperature at all
hours to simplify this complex process. However, control
systems have a throttling range, varying the room air
temperature. Using night set up or not cooling during
unoccupied times may cause an increase in room
temperature and a decrease in convection, effectively
storing heat for release. Later, on system start up, the
room air temperature rapidly decreases and a connective
rush of heat can occur. This is sometimes referred to as a Figure 4 - Peak Load Time Lag
pull down load. See Figure 5.

The TFM can calculate the effect of the changing room air temperature on the cooling and heating requirements. This is done
using the Space Air Transfer functions referred to as Heat Extraction. This can be thought of as a thermostat and pulldown
adjustment.

Figure 5 - Peak Loads: 24 Hours versus 16 hours

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Transfer Function Methodology (TFM)

The transfer function with heat extraction is implemented in three steps and two stages in HAP.

Stage One

Step One: The conduction equations are used to analyze the heat flow through walls and roofs.

Step Two: The room transfer functions are used to analyze the radiative, convective and heat storage processes of all
components. Convective components are instantaneous and radiative components are stored and released over time.

Stage Two

Step Three: The space air temperature transfer functions (heat extraction equations) are used to analyze the effects of the
changing room air temperature on convective heat flow from mass to room air that includes the behavior of the room
thermostat.

In the Stage One, Steps One and Two are completed assuming a constant room air temperature 24 hours. The components,
control zones, and the system are sized. These components comprise the Zone and Space Loads reported in HAP. See
Figures 7, 8, 9, and 10.

In the Stage Two, Step three calculations are done. The system is simulated using the sizing from the first stage to correct
the loads to what is needed to try to maintain set point. This is the “Zone Conditioning” reported in HAP (See Figures 7, 9, and
10.

To illustrate the results of this procedure, Figure 6

shows load, heat extraction, and room temperature
profiles for a scenario in which HVAC equipment
operates for the period 8 a.m. to 10 p.m., and is off
for the remaining hours of the day. Figure 6 shows
the cooling load profile calculated using the room
transfer function procedures and assuming a
constant room temperature. The actual room
temperature profile shows that during the 8 a.m. to
10 p.m. operating period; the equipment maintains
the zone within the thermostat throttling range of 72°
F to 76° F. During the off hours, the zone
temperature floats above the throttling range.
During this period, heat is accumulated in the
building mass. When the equipment operating
Figure 6 - Load, Heat Extraction, and Room Temperature Profiles
period begins at 8 a.m., this accumulated heat is
removed in addition to the hourly cooling loads. This
results in a pulldown component of the load.

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Transfer Function Methodology (TFM)

The HAP report “Air System Design Load Summary” (Figure 7) shows the results of the two stages of the calculation
procedure. The Total Zones Loads are the results of Stage One. The “Zone Conditioning” and “Total Conditioning" results are
from the Stage Two calculation.

Figure 7 - Air System Design Load Summary

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Transfer Function Methodology (TFM)

The Zone Design

Load Summary
and Space Design
Load Summary
reports (Figure 8)
show the detail of
the Stage One
results.

Figure 8 - Space Design Load Summary and Zone Design Load Summary Reports

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Transfer Function Methodology (TFM)

The Hourly Zone Loads report (Figure 9) shows the hourly results of the Stage One and Stage Two calculations as well as
the varying hourly zone air temperature achieved.

Figure 9 - Hourly Zone Load Report

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Transfer Function Methodology (TFM)

Graphing the column of numbers from the two stages can be done from the Hourly Zone Design Day Loads (see Figure 10).
The magnitude of the pull down load can be seen at 6 am. The extra amount of “conditioning” represents the true demand for
cooling needed for running 11 hours instead of 24 can easily be seen.

Figure 10 - Hourly Design and Day Loads

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Transfer Function Methodology (TFM)

As a review, when performing calculations to determine required airflow rates, supply terminal characteristics, and coil
capacities for HVAC systems, HAP uses the following general eight-step procedure:

1. Compute sensible and latent loads for all zones served by the HVAC system.

2. Sum zone loads to obtain sensible and latent loads for the HVAC system.

3. Determine required zone airflow rates.

4. Compute required sizes for terminal reheat coils as necessary.

5. Determine required system airflow rates. This includes sizing all fans and outdoor ventilation airflow rates.

6. Simulate HVAC system operation. Based on the required airflow rates determined in Steps 3 through 5. Operation of
the HVAC system is mathematically simulated to produce profiles of loads on central cooling and heating coils.

7. Identify peak coil loads. Cooling and heating coil load profiles from Step 6 are inspected to identify maximum loads.

8. Report results.

The results of these calculations can yield important benefits such as the ability to analyze the realistic transient heat transfer
that occurs in all buildings. Loads can also be accurately computed for any heat gain sequence and wall or roof construction.
Consequently, resulting loads are specific and customized for each application analyzed, accounting for local weather
conditions, building construction and operating schedules. The value of these benefits is obvious for HVAC design work.

Further articles in this series of HAP e-Help will build upon this discussion and explore how the HAP software can assist
system design rather than just load calculation.

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Zone T-stat Check

HAP users are occasionally puzzled by two outputs located on the Air System Sizing Summary in the Central Cooling Coil
Sizing Data area. These outputs are Zone T-stat Check and Max Zone Temperature Deviation (see Figure 1). This Article
will define these outputs and provide troubleshooting for common issues.

Please refer to HAP e-Help 004 - Transfer Function Methodology (TFM) for a description of the dynamic nature of cooling
loads. The ASHRAE design procedure requires a two-stage calculation, a sizing stage, and a simulation stage. In the sizing
stage zone sensible loads are computed assuming the zone is held exactly at the cooling thermostat setpoint 24 hours per
day. The results are used to determine peak zone and central coil airflow rates. HAP then simulates the system operation
using these airflow rates. The zone loads are then corrected for the actual system operating conditions. The simulation
accounts for the use of different setpoints during the occupied and unoccupied times or the shutdown of cooling during the
unoccupied period and the existence of a throttling range for the thermostats. Considering these real life operating factors
changes the thermal dynamics of the system, causing zone temperatures to vary within the throttling range and introducing
pull-down load components during the course of the day. In some cases, the sizing used is inadequate to maintain a zone
temperature during the simulation stage.

The Zone T-stat Check describes the status of zone air temperatures for the month and hour when the maximum cooling coil
load occurs. In this case, it is July 1400. This item is only provided for cooling control. The first value listed is the number of
zones with zone air temperatures that lie below the upper limit of the cooling thermostat throttling range. The second number
is the total number of zones in the system.

Figure 1 – Zone T-Stat Check

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Zone T-stat Check

Example: The sample-cooling coil sizing table shown in Figure 1 is for a VAV system that serves seven zones. The zone
cooling thermostat setpoint is 72° F with a throttling range of 3° F. For July 1400, when the maximum cooling coil load occurs,
the air temperature in two of the zones is at or below 75° F. Therefore, the output states “2 of 7 OK;” the numbers are
highlighted in red to bring it to the users’ attention.

This item is a useful check figure for confirming that the system is maintaining desired comfort conditions in the zones for the
hour when the maximum coil load occurs. When one or more zones are warmer than the upper limit of the thermostat
throttling range, it is often due to system operating problems in dealing with very large pull-down loads. These problems can
be investigated further by generating the Hourly Zone Design Day Cooling Loads and the System Psychrometrics reports.

Max Zone Temperature Deviation is used in conjunction with the Zone T-stat Check. It indicates the largest difference
between a zone air temperature and the upper limit of the cooling thermostat control range. When zone temperature problems
occur, it is used to judge the severity of the problem. If there are no zone temperature problems, this item will be displayed as
0. In our sample case, it is 10.1. There is at least one zone with a temperature of 85.1 (72.0 + 3.0 + 10.1), therefore further
investigation is required.

To determine which
zones are outside the
control range, the
System
Psychrometric Report
should be examined
(see Figure 2,
Table 2).

Figure 2 – Zone Temperatures

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Zone T-stat Check

Inspect the values in the Zone Temp column to identify the zones that are out of range. Next, examine the tabular and graph
data from the Hourly Zone Loads Reports (see Figures 3 and 4).

It can be seen from Figure 3 that the Hourly

Zone temperatures for the design day in
July are out of range for all hours of the
day. The graph helps to visualize the load
profile.

Internal loads commonly dominate zones

that are out of range. The graph in Figure 4
shows that the Zone Sensible load is rather
constant 24 hours a day. However, the
Zone Conditioning indicates an 11-hour on-
cycle for zone temperature control.

Figure 3 – Hourly Zone Loads Report

Figure 4 – Hourly Zone Design Day Loads

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Zone T-stat Check

Examination of the internal load schedule shows that these loads are constant over time as indicated in Figure 5. A more
realistic schedule should be considered as shown in Figure 6.

If the internal loads are constant for a long period of time, the on-cycle for cooling should be extended. In HAP, this is the Fan
and Thermostat schedule used with the Air System.

Figure 5 – Schedule Properties – 100%

Figure 6 – Schedule Properties, Lights - Classrooms

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Zone T-stat Check

Another way to diagnose this problem is to approach it as if it were a problem at job start-up. The first thing to try would be to
start the system up earlier in the day to see if a longer run-time will bring the temperature under control. Adjust the Fan and
Thermostat schedule, re-run the calculations, and check the results.

Another possible solution would be to cool with a set-up temperature during the unoccupied period. Adjust the unoccupied
setpoint values in the Air System input, make Unoccupied Cooling Available, and re-run the calculations and check the results
(see Figure 7).

Figure 7 – Air System Properties – Zone Components

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Zone T-stat Check

The last possible solution is to put more air into

the problem zones by using the User-Defined
sizing option in the Air System Sizing Data tab
and re-run the calculation (see Figure 8).

This error and the possible solutions to correct

this situation are due to inherent characteristics
of the Transfer Function Methodology.
See HAP e-Help 004 - Transfer Function
Methodology (TFM). Stage-one sizing is
performed with the system held at a constant
temperature for 24 hours. Stage-two then
simulates the system operation using the
stage-one sizing. If there are any problems, the
Zone T-stat Check will alert the designer that Figure 8 – Air System Properties – Sizing Data
changes to the model should be considered.

At this time, HAP does not have a warning indication to check for zone heating temperatures out of range. To check for
heating temperatures out of range, look at the System Psychometric Report for winter and inspect the zone temperatures.
This would be similar to Figure 2, Table 2 but for heating.

This concludes the explanation of the "Zone T-stat Check" and how to troubleshoot and remedy this problem should it occur.
The HAP program is a true HVAC system simulation tool, not just a load calculation program and as such can often be used
to troubleshoot system design or operational problems.

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Applying Schedules and Profiles in HAP

This HAP e-Help discusses the importance of properly applying schedules and profiles in HAP. We will also discuss potential
misapplications of these user inputs. First, we need to understand the differences between schedules and profiles and their effect
on design loads and energy simulation.

A “Schedule” is made up of one or more hourly “Profiles” and the associated day type “Assignments.” A fractional schedule is
used to describe how much and how often a building parameter like people, lights, and miscellaneous internal heat gains exist.
These schedules are then assigned to, and modify the internal loads defined in the space input forms.

Within a schedule, an hourly profile is used to describe

behavior for one 24-hour period. For example, a profile
for people would show the percentage of full occupancy
each hour for a 24-hour period. Schedules may contain
one or more profiles that together define the behavior for
the entire year. The example schedule shown in Figure 1
represents the “Lights” in a typical office application.
There are four profiles associated with this schedule: one
for the “Design Day”, one for “Weekdays”, one for
“Saturday-Sunday”, and one for “Holidays”. Together,
these profiles define the different behavior patterns for the
lights in the office.

Profiles can represent behavior for different days of the

week and different months of the year. In the example
above, additional profiles for summer weekdays,
fall/winter/spring weekdays, and weekends could be
added if desired. Users may describe up to eight
separate and distinct profiles depending on the usage
patterns of the building.

Figure 1 – Schedule Properties for Lights

Incorporating Four Profiles

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Applying Schedules and Profiles in HAP

Three Types of Schedules

There are three types of schedules in HAP: Fractional,

Fan/Thermostat, and Utility Rate Time-of-Day. Fractional
and fan/thermostat schedules are used in design load and
annual operating cost calculations. Utility rate time-of-day
schedules are used only in annual operating cost
calculations.

Fractional schedules represent hourly percentage usage of

the internal heat gain value. Fractional schedules are most
often used to describe the hourly variation of internal heat
gains such as people, lights, and miscellaneous heat
sources.

In addition to lights, people, and miscellaneous heat

sources, the fractional schedule can be used for special
“scheduled” control options for ventilation air, and to define
hot water usage.

The fraction of 100% heat gain for each hour is described

by the hourly profile. For example, the fractional profile for Figure 2 – Fractional Schedule Choice
a lighting schedule would define the fraction of 100% light
load for each hour of the day.

The “Design Day” profile in Figure 3 represents lighting for

an office area. This schedule has been named “Lights
Office”. Notice this profile calls for 100% of the light level
between the hours of 7 a.m. and 7 p.m. and 10% of the
light level for the remaining hours. As an example, suppose
the light heat gain was entered as 2.5 watts/sq ft. The
lighting wattage at this level would exist from 7 a.m. to 7
p.m., and lighting at 0.25 watts/sq ft would exist for the
remaining hours.

For information on how heat gains are converted into

cooling loads, see HAP e-Help 004 discussing the Transfer
Function Methodology.

Figure 3 – Typical Lighting “Design Day” Profile for an Office

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Applying Schedules and Profiles in HAP

Fan/Thermostat Schedules

Fan/Thermostat schedules define the hours when the HVAC equipment is operating in the “occupied” or “unoccupied” period.
Hours of the day in these profiles are designated as "occupied" or "unoccupied" and not fractional as with lights and people.
During occupied hours, the occupied thermostat set points are used and the air system fan operates to ventilate and condition
the building. During unoccupied hours, the unoccupied thermostat set points are used and the fan systems cycle to condition the
building. This type of schedule is selected in the “Air System Properties” under the “Zone Components” tab and the
“Thermostats” input by clicking the “Thermostat Schedule” button.

Figure 4 – Fan and Thermostat Schedules

In the “Design Day” Fan/Thermostat profile shown in

Figure 5, the HVAC system is started at 6 a.m. and the
occupied thermostat set points for cooling and heating
take effect at that time. At 7 p.m., the fan/thermostat
enters the unoccupied period and the fan cycles to
maintain set points. The Fan/Thermostat profile operates
independently of when the people enter the building and
the lights are turned on. However, there should be a
relationship between these schedules and their profiles
for the same project. For instance, it is not uncommon to
start the fan/thermostat an hour or more before the people
arrive, and stop the system operation and occupied set
point an hour or so after people leave.

The bar for each hour indicates operation for the full hour.
For example, if you have a bar for hour 09, that covers the
time period 9:00:00 a.m. thru 9:59:59 a.m. And a bar for
hour 18 covers the time period 6:00:00 p.m. thru 6:59:59
p.m. So, the schedule shown to the right results in an
occupied period beginning at 6:00:00 a.m. and ending at
6:59:59 p.m. If this is not understood, it is easy to
schedule operation 1 hour longer than intended. Figure 5 – Typical Fan/Thermostat Profile for Office

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Applying Schedules and Profiles in HAP

The last type of schedule represents the Utility Rate

Time-of-Day. It is used to define on-peak and off-peak
pricing periods for the electric rate. Figure 6 shows a
sample profile for this type of schedule. Notice that it is
different from the fractional and the fan/thermostat
profiles. This profile allows the user to input each hour
into one or up to four categories; peak, mid, normal, and
off-peak. In this example, the utility charges a “peak” rate
starting at 8 am and extending for 10 hours per day.
There are mid-peak rates for 2 hours before and after the
peak times. The other hours are off-peak. The user then
defines the actual rate in $/kWh for the various levels in
the electric and fuel rate property input screens.

Assignments

Now that we have described the three types of schedules

and their profiles, we will discuss the final input for
schedules: the assignment of the various profiles to the
days of the week and months of the year. Individual
profiles in a schedule can be assigned to different
months of the year or days of the week. This permits Figure 6 – Utility Rate Time-of-Day Profile
modeling of different internal load behavior patterns at
the different times of year or on different days of the
week. The “Assignments” tab in the Schedule Properties
input is used for this purpose.

For the example shown in Figure 7, we have assigned a

separate lighting profile for the “Design Day”,
“Weekdays”, “Weekends”, and “Holidays”. Profile 2,
“Weekdays” has been assigned to the Monday, Tuesday,
Wednesday, Thursday, and Friday day types for each
month of the year.

Assignments for the “Design” row of the table are only

used for the design cooling calculations. Assignments
for the days of the week are only used for energy
simulation calculations. As a note, when operating HAP
in the System Design mode to calculate cooling and
heating loads, only the “Design” row in the table is
enabled. All other rows (weekdays, weekends, and
holidays) are removed from view.

Figure 7 – Assignments

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Applying Schedules and Profiles in HAP

Important! Always Use Representative Profiles When Creating Schedules

Some HAP users question the relevance of inputting actual fractional profiles. Some may think they are simply being
conservative by leaving the profile multipliers at 100% for the entire 24-hour period. But what is the consequence of doing this in
the HAP program?

First and foremost, the hourly variations in heat gain from

lights, people, and other internal sources should be used
for each project. Also, only real life internal heat gains that
exist during known hours should be used. Granted, using
100% for all hours in a profile is the easiest to input.
However, heat gain in one hour has an effect on the loads
in subsequent hours because of the thermal storage
effect modeled by the ASHRAE Transfer Function
Method.

A 100% internal gain in all hours will essentially result in a

situation where the internal gain = internal cooling load for
stage 1 Transfer Function calculations. Stage 1
calculations are used to calculate zone and space
airflows.

In stage 2 calculations, HAP makes adjustments to the

stage 1 values, and then calculates the coil capacity
based on "actual" system operation. If the profiles for
internal gains are set at 100% for both the occupied and
unoccupied hours, enormous heat storage in the building
mass will occur during the unoccupied hours. This can
Figure 8 – 100% Values Not Recommended Unless
happen because the cooling setup temperature is higher
Applicable to Actual Building Usage
during the unoccupied times and/or the cooling equipment
is off at night.

The above described condition will result in a very large pull down load. This extremely large pull down load could result in the
peak coil load occurring in the morning instead of the late afternoon, which would have been the case with a more realistic
schedule. So, the actual time and magnitude of the peak cooling coil load has been skewed by the large pull down load. This
load would not exist if the internal gains were not present during the unoccupied periods.

Because of the large pull down load, the system will struggle to reduce the zone temperature to the cooling set point in a
reasonable time during the occupied period. This can result in unsatisfied and higher than expected zone temperatures. (See
HAP e-Help 007 for additional information on Zone T-Stat Check.) This struggle occurs because the airflow being used to pull
down the load at the onset of the occupied cycle has, in fact, been sized based on stage 1 calculations. These calculations do not
account for the unrealistic pull down requirements. However, the size of the cooling coil does take into account pull down if it
exists. So, a larger cooling coil load will be sized versus a scenario where less or no pull down is required.

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Applying Schedules and Profiles in HAP

So, why not use continuous internal heat gains at 100% and run the fan/thermostat schedule for 24 hours? This way, no pull
down loads exist, right?

This is not advisable. HAP may undersize the cooling coil since no pull down loads exist because the system does not have an
occupied period with a lower set point temperature. At that point, many engineers would attempt to apply a suitable safety factor
to account for the pull down load. However, the magnitude of the pull down load can be accurately calculated by HAP with
suitable attention to realistic profiles representing the internal loads.

What is the energy consumption and operating cost penalty if the internal loads are not correctly profiled?

The energy use and operating costs will be higher. In addition, the exaggerated heat gains can also offset heat losses in the
transition seasons and in winter, further skewing results. Hours of cooling operation will be larger than they should be. Hours of
heating operation will be less than they should be. In some cases, all hours of heating operation will disappear due to
overestimating the hours when heat gains occur. As a result, answers can not only be overstated, but seriously skewed (all
cooling operation, no heating operation, for example). Lastly, since alternative designs are often compared on the basis of %
savings, the % value will be unreliable because the totals are inflated. Demand charges could also be skewed.

Pre-Defined Schedules with the Building Wizard

The new Building Wizard feature in HAP version 4.3 provides a

quick method of entering space, schedule and construction data.
The Building Wizard is useful when developing schematic
designs, performing preliminary design work and creating
screening studies. Pre-defined schedules have been incorporated
into the Building Wizard and include occupancy, overhead
lighting, and electrical equipment in a ready-to-go quick select
format that is based on the type of building under consideration.
All of the pre-defined schedules in the Building Wizard can then
be customized by the user if desired.

The validity of the building model for load estimating and energy
simulation depends on representative inputs relative to internal
loads. Since a large part of the total load and operating cost in a
building involve internal loads like people and lights, Carrier Figure 9 – Building Wizard Pre-defined Occupancy
recommends utilizing realistic and representative profiles in order Schedules
to maintain accurate results.

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ASHRAE 62.1-2004 Ventilation Air Sizing in HAP

This HAP e-Help will explain how ASHRAE 62.1-2004 ventilation requirements are determined in HAP 4.3. Differences between
Standard 62.1-2004 and Standard 62-2001 will be examined with respect to space usage and outdoor air requirements. We will
examine how HAP determines the minimum system ventilation (outdoor air) requirement per 62.1-2004 at the space level and
then at the system level which is the outdoor air (OA) intake of the HVAC unit. Finally, we will review the Ventilation Sizing
Summary report for a VAV system using ASHRAE Standard 62.1- 2004 ventilation air preference.

HAP e-Help # 006 titled “Ventilation” dated November 2, 2005 is prerequisite reading to this discussion. It examines ASHRAE
Standard 62-2001, and “user defined” ventilation sizing method. It explains the hierarchy employed by the software to determine
the ventilation air requirements of the HVAC system. Ventilation airflow control methods are also explained including constant,
proportional, scheduled and DCV (demand controlled ventilation).

Background on ASHRAE Standard 62

Since its introduction, Standard 62 from the American Society of Heating, Refrigerating and Air-Conditioning Engineers
(ASHRAE) has been the primary design reference affecting the ventilation aspects of HVAC systems. ASHRAE Standard 62.1-
2004, is the most recent ventilation standard. As shown below, the standards for ventilation air have evolved over the years to
accommodate the changing design trends in the industry.

ASHRAE Standard 62.1-

2004 Available As A
Ventilation Preference in
HAP Version 4.3

Figure 1 - Evolution of ASHRAE Ventilation Standards

The purpose of ASHRAE 62.1-2004 is to specify minimum ventilation rates to help achieve acceptable indoor air quality. Since
contaminants in indoor air can be diluted by supplying the space with uncontaminated outdoor air, ASHRAE established
ventilation rates in Standard 62.1-2004 based on achieving this dilution. Constant dilution to ASHRAE 62.1-2004 minimums is
considered good design practice in order to achieve acceptable indoor air quality.

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ASHRAE 62.1-2004 Ventilation Air Sizing in HAP

Setting Up an ASHRAE Standard 62.1-2004 Project in HAP 4.3

The “Preferences…” option on the “View” menu is used to specify the preferences affecting the entire project including the
ventilation calculation method. See Figure 2 below. HAP version 4.3 and later includes the choice for ASHRAE Standard 62.1-
2004 in addition to the "User-Defined", and Standard 62-2001 method.

Figure 2 - View Preferences

ASHRAE Std. 62.1-

2004 Choice Applied
to Current Project

Figure 3 - ASHRAE 62.1-2004 Choice in HAP 4.3

When a new project is started in HAP, the user decides on which ventilation method to use. If ASHRAE 62.1-2004 is desired, it
must be selected for each new project. At the time this e-Help was written, HAP defaults to the earlier ASHRAE Standard 62-
2001 since many building codes still reference 2001. The ventilation setting is project-specific. It is not a global HAP setting. If
a user decides to standardize on the newer 62.1-2004 method, it must be selected for each project in HAP 4.3.

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ASHRAE 62.1-2004 Ventilation Air Sizing in HAP

Defining the Space Ventilation Requirements using ASHRAE 62.1-2004

If one of the two ASHRAE ventilation methods is chosen, HAP will use the specific Space Usage options and the OA
requirements that comply with that Standard. For example in Figure 4, the Space Usage options displayed by HAP in the Space
Properties input screen reflect specific values from ASHRAE Standard 62.1-2004 previously selected under View “Preferences”.
Notice there is a note at the bottom of the Space Properties window that serves as a reminder which source of defaults has been
selected.

Space Usage Options

Reflect Project-Level
Ventilation Preference
Choice

OA Requirements
Reflect Project-Level
Source of Ventilation
Ventilation Preference
Defaults
Choice
Displayed

Figure 4 - HAP Space Properties Input Screen

ASHRAE Standard 62.1-2004 revised the outdoor air requirements for various types of space usages. The Standard also
completely overhauled the methods for determining minimum airflow rates of outdoor air. A portion of a key ASHRAE table of
minimum ventilation rates is shown in Figure 5. We will now discuss these changes in detail and how they are applied in HAP.

Figure 5 - Minimum Ventilation Rates ASHRAE 62.1-2004

(Reproduced with permission from ASHRAE)

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ASHRAE 62.1-2004 Ventilation Air Sizing in HAP

Differences between ASHRAE 62-2001 and ASHRAE 62.1-2004

ASHRAE 62.1-2004 determines the total outdoor airflow rate for the system using the Ventilation Rate Procedure from Section
6.2 and Appendix A in the Standard. This procedure involves a two-part OA requirement unlike the previous standard ASHRAE
62-2001. The first part uses per-person criteria and addresses CO2 and people-generated pollutants or odors. The second part
uses a per-floor area to address pollutants generated by materials in the space such as carpeting and furnishings. In contrast,
Standard 62-2001 requires just a one-part OA requirement as shown below.

Differences exist in the space usage choices between the two Standards. Figures 6 and 7 allow visual comparisons between
Standard 62-2001 and 62.1-2004 in the Retail and Education category.

(8) ASHRAE 62-

2001 RETAIL
Space Usage
Choices

Single Part OA
Requirement

ASHRAE 62-2001

(7) ASHRAE 62.1-

2004 RETAIL
Space Usage
Choices

Two Part OA
Requirement

ASHRAE 62.1-2004

Figure 6 - RETAIL Space Usage Comparison

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ASHRAE 62.1-2004 Ventilation Air Sizing in HAP

Shown below are the space usage comparisons in the EDUCATION category. Notice the quantity of space usage choices has
remained the same, but the space usage names have been revised in Standard 62.1-2004.

(8) ASHRAE 62-

2001 EDUCATION
Space Usage
Choices

Single Part OA
Requirement

ASHRAE 62-2001
(8) ASHRAE 62.1-
2004 EDUCATION
Space Usage
Choices

Part One - CFM

per Person

Part Two - CFM

per Floor Area

ASHRAE 62.1-2004

Figure 7 - EDUCATION Space Usage Comparison

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ASHRAE 62.1-2004 Ventilation Air Sizing in HAP

Standard 62.1-2004 Ventilation Air Sizing Calculations in HAP

The procedure to calculate the ventilation airflow in Standard 62.1-2004 involves 2 major steps. The first step determines the
space ventilation airflow. The second determines the total system ventilation airflow.

It is important to note that the second step determines how much ventilation airflow is required at the central system intake to
ensure that each space receives its required ventilation. As we will see, the ventilation airflow required at the intake can be larger
than the sum of the uncorrected space airflows. A term called system ventilation efficiency is calculated in this second step in
order to determine the final ventilation amount at the unit intake. These terms and associated calculation methods are described
below.

Before we continue, we should clarify some terminology between HAP and ASHRAE. The term "zone" is used in ASHRAE
Standard 62.1-2004 to refer to what HAP identifies as a "space". To avoid confusion, this E-Help will adopt the HAP terminology.
For example, later when we discuss what the Standard refers to as "zone ventilation efficiency" will be referred to in this e-Help
as "space ventilation efficiency" for clarity.

Step 1: Space Ventilation Airflow

The space ventilation airflow calculation involves 3 separate considerations which collectively yield the required space ventilation
airflow.

1. Calculate the time averaged occupancy for short-term conditions

2. Add the CFM/person and CFM/sq ft requirements for each space
3. Assign the space air distribution effectiveness

Calculation of Space Ventilation Requirements

1. Calculate the Time Averaged Occupancy

If the number of people in the space fluctuates over time, Standard 62.1-2004 allows the space population to be estimated
using a time averaging procedure. HAP applies the user’s fractional people schedule along with the equations in paragraph
6.2.6.2 of ASHRAE Standard 62.1-2004 to produce an “averaging time period”. The interval length is a function of the
ventilation air change for the space. Average occupant schedule values are calculated for this interval and the largest
average value is used to determine the time averaging factor. This factor is then used to correct the OA ventilation amount
(CFM/person) described in item 2 below.

As an example, suppose a 2000 sq ft space with floor to ceiling height of 9 ft has 10 occupants and uses the occupant
schedule shown in Figure 8. The requirements for this space are 5 CFM/person and 0.06 CFM/sq ft. Without considering
time averaging, the uncorrected outdoor airflow would be 170 CFM. To consider time averaging, the averaging interval must
first be determined. The time averaging interval equation from the Standard is 3 x Space Volume / Uncorrected Outdoor
Airflow or 3 x 18000 / 170 which equals 318 minutes or 5.3 hours. This is rounded to 5 hours. Next, the program calculates
an average schedule factor for each group of 5 consecutive hours in the people design day schedule. First, hours 0000 thru
0400 are used, then 0100 thru 0500, then 0200 thru 0600, etc. The average schedule factor for the interval 1200-1600 in
Figure 8 would use the five consecutive schedule values of 50%, 100%, 100%, 100% and 40% to determine an average of
390/5 or 78%. Once averages are calculated for all 5-hour blocks in the day, the largest average is used as the Time
Averaging Factor. In the case of Figure 8, the largest average occurs during the interval of 0800-1200 and is 90%. That
means the people count is 0.90 x 10 occupants = 9 occupants. If we take 5 CFM/person X 9 people we now have 45 CFM
versus 50 CFM initially resulting in a reduction of 5 CFM for the space. So the sum of the two part OA requirement is 165
CFM instead of 170 CFM.

If the people schedule uses 100% for all hours the Time Averaging Factor would be 100%.

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The time averaging factor does not always result in a downward correction to the people occupancy and an associated
decrease in ventilation airflow. It depends on the space volume, people occupancy, and profile. For example, suppose a 900
sq ft classroom has 30 occupants, requires 10 CFM/person and 0.12 CFM/sq ft and uses the occupant schedule in Figure 8.
The uncorrected outdoor airflow is 408 CFM. The time averaging interval from the ASHRAE equation is 3 x Space Volume /
408 CFM which equals 60 minutes or 1 hour. In this example the program calculates an average schedule factor for each one
consecutive hour. The largest one hour “average” in this case is 100%, so for this classroom there is no change to the original
uncorrected ventilation airflow based on the time averaging factor.

Figure 8 - People Profile for Classroom

2. Add the OA Requirements for Each Space

During sizing calculations for Standard 62.1-2004, HAP will first correct the occupancy based on the Time Averaged
Occupancy method described above. Then HAP will sum the per person and per sq ft OA requirements to obtain the total OA
requirement for each space. This is called the “uncorrected outdoor air” for the space.

3. Assign the Space Air Distribution Effectiveness

The next consideration that affects the required space outdoor airflow amount involves the air delivery from the diffusers. The
Air Distribution Effectiveness is a new concept in ASHRAE 62.1-2004. It is not enough to simply deliver ventilation air to a
space. The air must effectively reach the breathing zone of the occupants. Standard 62.1-2004 says a system that is effective
at delivering air to the breathing zone would require less outdoor airflow than a less effective system for the same space.

The breathing zone is defined as the space between 3 and 72 inches above the floor as shown in Figure 9. When supply air
is delivered anywhere above the breathing zone, it is considered to be the same as ceiling delivery. Since different types of
systems and air terminals are more or less effective at delivering ventilation air to this breathing zone, the effectiveness of the
air distribution system is considered by HAP in calculating ventilation requirements.

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Cooling applications that deliver the air through ceiling diffusers will have an effectiveness value of 1.0. If sidewall supply
registers are higher than 72 inches above the floor, then they are considered "ceiling supply" and the effectiveness value of
1.0 still applies.

If sidewall supply is higher

Effectiveness of 1.0 is than 72 inches from floor, it
used for cooling via is considered the same as
ceiling diffusers the ceiling

The Breathing Zone is

between 3 and 72 inches
above the floor.

Figure 9 - Space Air Distribution Effectiveness

Per ASHRAE 62.1-2004, systems that deliver warm air from a ceiling supply diffuser, and have supply air 15°F or more above
room air temperature, have an effectiveness of 0.8. Systems with warm air supplied from a ceiling diffuser, with a temperature
less than 5°F warmer than the room air, have an effectiveness of 1.0.

The required outdoor air for a space is then calculated as the uncorrected outdoor air (from Step 1, part 2 above) divided by
the Space Air Distribution Effectiveness. For example, if the uncorrected outdoor air is 408 CFM and the Distribution
Effectiveness is 0.8, the required outdoor air for the space is 408 / 0.8 or 510 CFM. Standard 62.1-2004 refers to this result
as the “Zone Outdoor Airflow”. HAP lists this result as “Required Outdoor Air” on its reports.

Step 2: System Ventilation Requirements

Step 2 determines how much ventilation air is required at the common OA intake to ensure that each space receives its required
ventilation. As we will see, the ventilation airflow required at the intake can be larger than the sum of the required outdoor air for
the spaces due to issues related to the “critical space”. Determination of the OA amount at the unit intake also involves
calculation of a space and system “ventilation efficiency” value per formulation in ASHRAE 62.1-2004 Appendix A. This section
discusses the procedures for system level ventilation calculations, but there will still be considerable discussion involving spaces.

“Critical Space” involves a concept that meeting the ventilation requirements of one space may require over ventilating other
spaces. The outdoor air fraction, which is space ventilation CFM divided by supply air CFM, is important in understanding critical

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space concepts. As an example, consider Figure 10. Suppose the rooftop serves only two spaces and suppose space A
requires supply airflow of 800 CFM and outdoor ventilation air of 200 CFM, for an outdoor air fraction of 25%. Also suppose
space B requires 600 CFM of supply air and 300 CFM of outdoor ventilation air for an outdoor air fraction of 50%. Both spaces
receive supply air from the same rooftop unit. If that supply air contains 25% ventilation air, the ventilation requirement of Space
A will be met, but the ventilation requirement of Space B will not be met.

Critical Space Concept

Applies to HVAC Air
System Serving
Multiple Spaces

Common OA
Intake Serving
All Spaces
Return Air Other Spaces
Require Less %
Space A Requires OA than Space B
25% OA

Space B (Critical) Legend

Requires 50% OA
Space A Space B Other Spaces OA SA

Figure 10 - Typical VAV System and Critical Space

So, the common supply air must contain more than 25% outdoor air in order meet Space B requirements. Suppose the common
supply air is increased to contain 50% outdoor air. This will over ventilate Space A. However, once Space A is over ventilated,
there is unused or "unvitiated" ventilation air that recirculates from Space A and that moderates the need to increase supply air
all the way to 50% ventilation. If we perform the ventilation efficiency calculation described in Appendix A of Standard 62.1-2004,
we find that supply air must be 41.7% outdoor air in order to satisfy both Space A and Space B ventilation requirements. 41.7%
is less than the 50% outdoor air required by Space B so it appears Space B is under ventilated. But Space A is over ventilated
and recirculation of the unused ventilation air from Space A makes up the difference required for Space B so its ventilation
requirement is met.

In this example, the space ventilation efficiency for Space A was 1.107 while for Space B it was 0.857. Space B is the critical
space because it has the smaller ventilation efficiency value. The system ventilation efficiency is equal to the critical space’s
ventilation efficiency, so the system efficiency is 0.857. Then, the required outdoor airflow for the system is the uncorrected
airflow divided by the system ventilation efficiency, or 500 / 0.857 = 583.4 CFM. With 1400 CFM supply air in this example and
583.4 CFM of outdoor ventilation air, ventilation is 41.7% of supply.

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The Critical Space concept existed in ASHRAE 62-2001. However, the mathematics for handling it is different in Standard 62.1-
2004 and a new term called “ventilation efficiency” is used. The Standard defines a complex calculation procedure which HAP
follows to determine the ventilation efficiency for each space. This calculation procedure is different depending if the system is a
single duct type (like constant volume single zone versus a dual duct) or recirculation system (such as a fan powered VAV
system). The recirculation systems require a more involved calculation.

HAP performs the entire Standard 62.1-2004 calculation twice for each system if the system provides cooling and heating. It
performs it once assuming cooling operation. Then it does it again for heating operation. The larger system ventilation CFM is
used as the final result. If heating duty results in the larger ventilation airflow requirement, then HAP uses a space air distribution
effectiveness of 0.8 (reflecting warm air supply typically 15°F or more above room temperature) for all spaces in the system.

Note: For dedicated ventilation systems providing 100% outdoor air to all spaces as shown below, the total system ventilation
airflow is simply the sum of the ventilation values for all spaces in the system. The required air for each space is set at the
diffuser and the 100% OA unit is sized for the sum. There is no “critical space” calculation required.

Dedicated
OA Unit Separate HVAC Unit for
Critical Space Space Conditioning
Concept Does
Not Apply

Figure 11 - No Critical Space Issues with Dedicated OA Unit

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Understanding the Ventilation Sizing Summary Report

The last section of this HAP e-Help will use the information from our discussion so far to interpret the output data from the
Ventilation Sizing Summary. The example system is a 7-zone VAV system supplying multiple classroom spaces similar to the
one used previously in this e-Help. Also included in the system are a small computer lab, corridor, and vestibule. ASHRAE 62.1-
2004 ventilation air preference has been chosen at the project level.

The total cooling coil for this 7 zone system is 26.4 tons at August 1500 as shown below. This reflects a Design Ventilation
Airflow Rate calculated by HAP based on ASHRAE 62.1-2004 requirements of 2547 CFM. Notice the Design Condition for
ventilation air is at the “minimum flow (heating)”. As discussed previously, because this is a cooling and heating system, HAP
does the Standard 62.1-2004 ventilation air calculation once for cooling and once for heating and uses the higher of the two
values. In this example, heating duty was higher because the heating duty air distribution effectiveness was lower (0.80) than
cooling duty (1.0) which results in 25% more ventilation air requirement to each space during the heating cycle.

Total VAV Coil Load

Design Ventilation Airflow Rate = Uncorrected CFM /

Ventilation Efficiency = 1760/.691 = 2547 CFM

Critical Space Ventilation

Efficiency = .691

Figure 12 - Ventilation Report for VAV System

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The following explains the column headings in the Ventilation Report for a VAV system. Refer to Figure 12.

Minimum Supply Air (CFM)

This value represents the minimum supply airflow (not just the outdoor airflow) for the VAV terminal service each zone. The
minimum supply airflow for each zone in this example system was entered as 50% of the supply terminal airflow under Zone
Components/ Supply Terminals/ Minimum Airflow. Notice in this example the Design Ventilation Airflow is less than the Minimum
Supply Air CFM. HAP automatically adjusts (overrides) the minimum box supply air CFM upward as required if the user’s input
value for minimum box airflow does not accomplish required minimum ventilation.

As an added note, this column heading only appears for VAV systems. For a CAV system the heading would say “Maximum
Supply Air (CFM). That is because a CAV system diffuser has no minimum airflow setpoint like a VAV terminal.

Floor Area (sq ft)

This is the space floor area used in the uncorrected ventilation airflow calculation that is based on CFM/Sq Ft.

Required Outdoor Air (CFM/Sq Ft)

This represents the part two value for the OA requirement based on Space Usage in ASHRAE 62.1-2004.

Time Averaged Occupancy

This value represents the number of occupants used in the final calculations for ventilation air. Any headcount reductions have
been taken into account based on the time averaging factor calculations discussed earlier in this HAP e-Help.

Required Outdoor Air (CFM/Person)

This represents the part one value for the OA requirement based on Space Usage in ASHRAE 62.1-2004.

Air Distribution Effectiveness

This value takes into consideration the ability of the supply air from the diffusers or registers to effectively reach the breathing
zone of its occupants. In our case a value of .8 was used because heating duty ventilation airflow (0.80 effectiveness) exceeded
cooling duty ventilation airflow (1.0 effectiveness).

Required Outdoor Air (CFM)

This column contains the calculated outdoor air quantities after taking into account the air distribution effectiveness. The
uncorrected outdoor air CFM divided by the air distribution effectiveness is the required outdoor air CFM for each space. This is
not the final airflow for the common OA intake for the system.

Uncorrected Outdoor Air (CFM)

This column contains the part one and two outdoor air quantities before taking into account the air distribution effectiveness and
critical space issues. The time averaging factor for occupancy determination has been applied to this value however.

Space Ventilation Efficiency

Space ventilation efficiency is used to identify the critical space in the system. The space with the lowest ventilation efficiency is
the most critical therefore it dictates the outdoor airflow for the system to ensure it receives its required airflow. The Uncorrected
Outdoor Air (1760) divided by the lowest Space Ventilation Efficiency (.691) value is the final answer called Design Ventilation
Airflow Rate (2547).The Space Ventilation Efficiency is calculated by HAP using the procedures in Appendix A of the Standard,
as opposed to using the more simplified method in table 6-2.of the Standard. This results in the highest level of accuracy.

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Conclusion

ASHRAE Standard 62.1-2004 requires HVAC systems to introduce outdoor air at specified minimum ventilation rates to minimize
the potential for adverse health effects while remaining acceptable to the human occupants.
Determining the ventilation airflow for each space involves summing a two part OA requirement then applying a time averaging
factor that adjusts for occupant fluctuations in the space. Differences exist in the space usage choices between the older
Standard 62-2001 and Standard 62.1-2004.

Next, HAP considers the ability of the cooling/heating system to deliver air to the breathing zone according to Standard 62.1-
2004. This is represented in terms of an effectiveness value that will increase the required space ventilation airflow to
compensate for a less effective air delivery.
Then, HAP uses ASHRAE 62.1-2004 formulas to determine how much ventilation air is required at the central system intake to
ensure that each space receives the required ventilation. This process involves finding the critical space. The critical space
exhibits the lowest ventilation efficiency and dictates the overall outdoor airflow for the system.

The purpose of ASHRAE 62.1-2004, is to specify minimum ventilation rates to help achieve acceptable indoor air quality through
constant dilution with outdoor air. These minimums are considered good design practice in order to achieve acceptable indoor air
quality. HAP version 4.3 and later incorporates the ability to satisfy the requirements of Standard 62.1-2004 for the project
ventilation preference.

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How to Import Data from Template Projects

HAP allows data to be imported from other projects to help save time when entering project library information. This procedure
takes advantage of “template” projects to easily access previously created project libraries. Information such as Schedules and
data defining Walls, Roofs, Windows, and Doors among other project library items can be imported from the previously created
projects. This e-Help describes how to save time by using the Import Data feature in HAP.

The “Import HAP Project Data...” feature will be demonstrated using schedule information from the Project Library in an existing
active project. For this example, the active project called the “East Bradford High School” will import schedule data from a
template project called “Sample ASHRAE 90.1-2004 Schedules”. A list of schedules for both projects is shown in Figures 1 & 2.

Figure 1 – East Bradford High School Figure 2 –Schedules from the Template Project

From Figure 1, it can be seen that some schedules have already been entered for the Gym, Corridors and Utility Rates.
However, the sample ASHRAE 90.1-2004 schedules for the classrooms are desired. Rather than manually entering the
schedule data into the high school project, this information can be imported from the Sample ASHRAE 90.1-2004 Schedule
template project. The procedure to accomplish this is described below.

Importing HAP Project Data

Use the following process to import data from another project.

1. Open the HAP project that requires the new project library data. In this
case, schedules will be imported into the East Bradford High School
project.
2. From the Project menu, select “Import HAP Project Data…” as shown
in Figure 3.
3. This opens the Select Project window shown in Figure 4.

Figure 3 – Import Data Option

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How to Import Data from Template Projects

4. Highlight the name of the project that contains the project library
data to import from. In this example, the template project called
“Sample ASHRAE 90.1-2004 Schedules” will be selected as the
data source for the library items.
5. Click on OK to open the selected project.
6. The Select Data to Import window, Figure 5, appears.

This window contains three sections:

- Data Categories – Choose the data type to Import.
- Select Data to Import from Source Project – The specific data
for the selected category in “Sample ASHRAE 90.1-2004
Schedules”.
- Contents of Current Project – Shows the existing data in the
current project for the selected category.
Figure 4 – Select Project
7. Select the desired Data Category. In this example, Schedules
is selected.
8. Choose the specific items to import. In this example, (4) “School” schedules will be imported.
9. Click the Import button.

Figure 5 – Select Data to Import

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How to Import Data from Template Projects

10. An Import Data window, similar to Figure 6, shows the number of

each item that will be imported. Click Yes to import the selected
items.
11. The Import Data window will update to show the number of items
that were successfully imported into the East Bradford High School
project. Click OK to close this window.

The import of (4) schedules from the “Sample ASHRAE 90.1-2004

Schedules” template project is complete.

To view the schedules that were imported, select Schedules under the
Project Library in the project tree. Figure 7 shows the new schedules in
the East Bradford High School project that were imported from the
template project. The import process does not overwrite existing project
library data in the current project. For example, if the “90.1 School Lights
& Plug” schedule was already in the project, the imported schedule
would be shown as “90.1 School Lights & Plug(1)”.

Please note: Importing the data does not automatically assign it to the
Spaces, Systems, Plants or Buildings for which it is needed. The user
can now assign the library items as needed in the current project. Figure 6 – Import Data

Summary

HAP’s import feature can quickly populate a new project

with project library data originally entered in another
project. This feature also allows the user to establish a
series of helpful template projects representing standard
data for items such as Schedules, Walls, Roofs and
Windows.

A future HAP e-Help will provide a link to the project

archive containing the sample ASHRAE 90.1-2004
schedules used in this example. When released this e-
Help can be found on the Carrier website at
http://www.commercial.carrier.com/commercial/hvac/gen
eral/0,3055,CLI1_DIV12_ETI10111_MID5169,00.html#H
APehelp.

Figure 7 – Schedule Data after Import

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How to Archive/Retrieve Project Data

HAP allows for transfer of a project from one computer to another through an Archive / Retrieve process. Archiving a project
bundles all of the data on the project together in a single file. This is useful for backing up the data, storing the project for future
reference or transferring data from one computer to another. Note that Archive does not remove the project from HAP; it simply
exports the project data in the current state. The Retrieve option in HAP brings this project into the other computer or to the
same computer when restoring from backup.

Archive Project

To send the project to another system, it must first be exported from HAP using
the Archive feature of the program. To archive a project, complete the following
process:

1. Open the desired project. NOTE: HAP only archives the active project.
2. Once the project is open, go to the Project menu and select “Archive HAP
v4.3 Data…” as shown in Figure 1.
3. This opens the Archive window as shown in Figure 2.
4. Use the “Save in:” drop down at the top of this window to select the location
to save the file. The destination folder specified can be the local hard drive,
and network drive, or a removable media device such as a ZIP disk, floppy
disks or a USB drive.
5. Enter a name for the archive file in the “File name:” field at the bottom of the
window. This field defaults to the current project name. Figure 1 – Archive Project Option
6. Click Save to export the project data to the specified Archive file.
7. A pop-up window, similar to Figure 3, appears when the archive is
completed. This shows the project name and the location of the exported file.

Specify the
save location

Enter the
file name
Figure 3 – Archive Completed Window

Figure 2 – Archive Window

Transferring the File

Now that the archive file exists, transfer this file to the new computer. This can be done through e-mail, network drive, or a
removable media device (USB drive, CD, etc.). Once the file resides on the new computer, use HAP on that machine to import
the project data through the Retrieve process.

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How to Archive/Retrieve Project Data

Retrieving Project Data

A project is typically retrieved when receiving archive data from another computer, when referring to an old project that was
archived for safekeeping or when restoring data after a hard disk failure. For purposes of this e-Help, it is assumed that the
project data is being sent from another computer. Once the archive file has been received, this data can be brought into HAP
on the current computer through the Retrieve functionality.

Retrieve a v4.3 Project

To Retrieve a project into HAP, complete the following process:

1. Save the .e3a archive file to the local hard drive.

2. Open HAP. Start a new “untitled” project. NOTE: If data is retrieved to an
existing project, the HAP data in the project will be replaced with the data from
the archive.
3. Go to the Project menu and select “Retrieve HAP v4.3 Data…” as shown in
Figure 4.

Figure 4 – Retrieve Project Option

4. This opens a Retrieve window as shown in Figure 5 which

allows for the selection of the archive file.
5. Use the “Look in:” drop-down at the top of this window to
select the location where the file was saved in Step 1.
Specify the
6. Select the file to add the name to the “File name:” field at
location of the
the bottom.
archive.
7. Click Open to open the selected file.

Select archive to
enter the file name

Figure 5 – Retrieve Window (Select File)

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How to Archive/Retrieve Project Data

8. A Retrieve window as shown in Figure 6 appears showing

information about the project file.
9. Ensure that the “Contains Data For” area of this window
shows that it contains data for “Hourly Analysis Program
v4.3”. If the project contains data from version 4.2 or earlier,
there is a separate process to Retrieve that data discussed
later in this document.
10. Click on Retrieve to bring the project data into HAP. When
complete, a message box appears showing whether or not
the retrieve was successful as shown in Figure 7. Click on
OK to close this message.
11. The data for the project that was just retrieved appears in
the window (see Figure 8). Retrieving a project only loads it
into the HAP program, be sure to Save the project as well.

Figure 6 – Retrieve Window (Project Data Preview)

Figure 7 – Completed Status

Figure 8 – Project data retrieved into HAP

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How to Archive/Retrieve Project Data

Convert v4.2 (or earlier) archive

HAP v4.3 allows for the retrieval of project data from previous versions
of the program. This is done through the Convert process. If unsure of
what version of HAP a project archive came from, follow the steps in
the Retrieve Project section above, and pay particular attention to step
9. If the “Contains Data For” section listed “Hourly Analysis Program
v4.2” (or earlier) as shown in Figure 9, then the project archive must go
through the conversion process.

The conversion process will extract the data from the archive file, and Project contains
then convert it to the HAP v4.3 format. Data will be saved in the
data from v4.2
current HAP v4.3 project folder.

To convert a project, use the following process:

1. Open HAP. Start a new “untitled” project. NOTE: If data is

converted to an existing project, the HAP data in the project will be
replaced with the data from the converted archive. Figure 9 – Retrieve Window (Project Data Preview)

2. Go to the Project menu and select “Convert HAP v4.x Data…” as

shown in Figure 10.

Figure 10 – Convert Project Option

3. The Convert HAP v4.x window shown in Figure 11 appears.

4. Click on Archive File to launch the Convert from Archive File
window in Figure 12.

Figure 11 – Convert HAP Data Window

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How to Archive/Retrieve Project Data

5. Use the “Look in:” drop-down at the top of the window to select
the location where the archive file is saved.
6. Select the file to add the name to the “File name:” field at the
bottom. Specify the
7. Click Open to open the selected file and begin the conversion location of the
process. archive.
8. When complete, the message box shown in Figure 13
appears. This indicates that the data translation was
successful. Click OK to close the screen, or Help to view
information on what data should be checked after the Select archive to
conversion. Clicking Help brings up the screen shown in enter the file name
Figure 14.

Figure 12 – Convert from Archive File

Figure 13- Conversion Successful

Because the data is translated from the older version of HAP to

version 4.3, the result is the original data with missing items added,
unusable items discarded and other items reorganized.

Select the option at the bottom of Figure 14 to view the changes in

data from the version of HAP that the archive was originally
created in. Each item indicates what data should be verified after
the conversion, including items such as input data and simulation
or calculation runs.

Convert v3.2 data

Select original version of
For more information on converting data from HAP v3.2, please project to review data points
consult the Help system in the current version of HAP. In the that should be checked
Contents of the Help system, select the topic entitled “Converting
Previous Version Data.” Within this topic, select the option for Figure 14 – Help Screen on Data Translation
“Converting HAP v3.2 Data” and then finally “About Translation of
HAP v3.2 Data” as shown in Figure 15. Click on the Display button
at the bottom of the screen to learn more about this process.

Figure 15 – Convert v3.2 Data Help Topic

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