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System Design Example Problem Chapter 3
Figure 3.18 D114 South Corridor
HAP Quick Reference Guide 3-23
Chapter 3 System Design Example Problem
Figure 3.19 D105 South Vestibule
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System Design Example Problem Chapter 3
Figure 3.20 D112 West Vestibule
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Chapter 3 System Design Example Problem
Figure 3.21 Packaged Rooftop AHU Inputs
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System Design Example Problem Chapter 3
Figure 3.21 Packaged Rooftop AHU Inputs (continued)
HAP Quick Reference Guide 3-27
Chapter 3 System Design Example Problem
Figure 3.21 Packaged Rooftop AHU Inputs (continued)
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System Design Example Problem Chapter 3
Figure 3.22 Air System Sizing Summary Report
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Chapter 3 System Design Example Problem
Figure 3.23 Zone Sizing Summary Report
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System Design Example Problem Chapter 3
Figure 3.23 Zone Sizing Summary Report (continued)
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Chapter 3 System Design Example Problem
Figure 3.24 Air System Design Load Summary Report
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Chapter 4 Energy Analysis Example Problem
This chapter contains a simple example problem which demonstrates how to use HAP to estimate annual
energy use and cost for a building. The example builds on concepts and procedures discussed in
Chapters 1 and 2. Note that these energy analysis features are available in HAP but not in HAP System
Design Load.
4.1 OVERVIEW FOR THE EXAMPLE PROBLEM
The procedure for conducting an energy analysis with HAP involves five steps previously discussed in
Chapter 1:
1. Define the Problem.
2. Gather Data.
3. Enter Data Into HAP.
4. Use HAP to Generate Simulation Reports.
5. Evaluate the Results.
The example problem presented in this chapter will demonstrate the first four steps in this process. In the
remainder of this chapter a separate section will deal with each step.
4.2 DEFINING THE PROBLEM
The objective of this example problem is to estimate annual energy use and energy cost for a building.
Normally an energy analysis compares energy use and cost for two or more design scenarios. To make
this example practical and efficient, the scope of the example will be limited to estimating energy use and
cost for a single design scenario. This will demonstrate the key steps in the energy analysis process. In a
real energy study, certain of the steps would be repeated to generate the additional design scenarios being
evaluated.
The example will analyze the classroom wing of the high school building used in the system design
example problem discussed in Chapter 3. The floor plan for this wing of the school building is shown in
Figure 4.1. It is comprised of six classrooms, a music room and its associated office, storage and practice
rooms, plus two corridors and two doorway vestibules for a total of 14 rooms.
The rooms in this portion of the school building will be air conditioned by one packaged rooftop unit
serving parallel fan powered mixing box (PFPMBX) terminals. A gas-fired preheat coil in the rooftop
unit and electric resistance heating coils in the mixing box terminals provide heating. HAP will be used
to simulate building loads and equipment operation hour-by-hour for one year in order to determine
energy use and energy cost.
HAP Quick Reference Guide 4-1
Chapter 4 Energy Analysis Example Problem
Figure 4.1 Floor Plan for School Building
4.3 GATHERING DATA
The second step in the analysis process is to gather information necessary to model heat transfer
processes in the building, to analyze operation of the HVAC equipment and to calculate costs for energy
and fuel use. This involves gathering data for the building, its environment, the HVAC equipment and
the utility rate structures. Below, each type of data will be discussed.
4.3.1 Gathering Weather Data
The same design weather conditions used in the system design example problem in Chapter 3 will be
used here: ASHRAE design weather conditions for Chicago O Hare International Airport, plus daylight
savings time specifications and cooling design calculation months (see Figure 3.2).
For the energy analysis, simulation weather data will also be needed. This is observed weather data for a
typical year spanning all 8,760 hours in the year. We will use the Typical Meteorological Year (TMY)
weather file for Chicago O Hare International Airport as the source of this data. This data is provided in
the library of HAP simulation weather data.
In addition, the operating calendar for the year must be specified. We will use a calendar with January 1st
falling on a Tuesday and having the following days designated as holidays:
4-2 HAP Quick Reference Guide
Energy Analysis Example Problem Chapter 4
Table 4.1 Calendar of Holidays
January 1 New Year s Day
April 15 19 Spring Holiday
May 27 US Memorial Day
June 22 August 11 Summer Holiday
September 2 US Labor Day
November 28, 29 US Thanksgiving Holiday
December 23 31 Christmas/New Year Holiday
4.3.2 Gathering Space Data
Data describing the heat transfer elements of each room in this wing of the building will be the same as
described in Chapter 3, section 3.3.2. This discussion in Chapter 3 covers wall, roof, window, door,
external shade, schedule and space data.
The only adjustment needed for energy analysis will be the assignment of schedule profiles to days of the
week and times of year. The School_In_Session profiles for each schedule will be assigned to
weekdays in all 12 months. The Weekend/Holiday profiles for each schedule will be assigned to
Saturday, Sunday and Holidays in all 12 months. Because we have designated the June 22 to August 11
summer shutdown period as holidays we do not need to create separate profiles representing operation
during the shutdown days. This expanded schedule data is shown in Figure 4.3.
4.3.3 Gathering Air System Data
One VAV packaged rooftop unit will provide air-conditioning to the rooms in this wing of the school
building. Heating will be provided by a gas-fired preheat coil in the rooftop unit and electric resistance
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