Energy-10 Help - Version 1.3

Architectural Engineering Design

J. Mitchell Notes - Taken from reading very good Help files in Energy-10

Information On This Page

    Building Size            <10,000SF Generally applicable,

    Energy Zones            only one or two energy zones, but not as limiting as this seems.

 

Energy-10 Concepts

Autobuild

Produces a “base-case”/ “dumb” building and an “optimized” building starting from that base case.

Bldg-1

The base-case building
Perhaps modify it as project develops to be more realistic

Bldg-2

The automatically optimized building
Modify this one continuously to reflect the actual design.
Use “transfer” or “swap” to develop these buildings.

Rank

Tests Strategies for saving energy and ranks them.

AutoSize

Sizes HVAC more accurately than rules of thumb

Operation

Can be turned on or off
Normally on
When on calculates appropriate size during Rank procedure
Recommended procedure
Leave on during preliminary design
Turn off once design is firmed up

Keep

The way of retaining results from different scenarios

 

Everything has Defaults

Energy-10 gives “reasonable” defaults for everything

Everything is modifiable to become more real

Apply

Allows application of Energy Saving Strategies to a design all at once to determine the effect.

Variant Concept Confusing

“The use of variants confuses users. Even the term is foreign. This will be fixed in Version 2, For now, we suggest that you learn the existing system, awkward as it is. It. will help to read Saving Your Work and Saving Project and Variants. Remember that a variant refers to the pair of Bldg.-1 and Bldg.2 building descriptions.”

Zones = Area conditioned by a single HVAC system

  • Only two zones are possible
  • Probably only use one zone for small buildings.
  • Note that for daylighting on larger buildings the program will automatically subdivide into five subzones.

“Zones HVAC Class

  HVAC Class is set during AutoBuild, depending on Building Use. It can be changed in the Building Zones dialog box. It toggles between Residential and Non-Residential.

 There are two general classes of HVAC systems modeled by CNE, those designed for residential use and those designed for non-residential use. Residential systems have no outside air damper. Non-residential systems have an outside air damper. The damper allows the system to draw in outside air, as required, for example to meet ASHRAE air-quality standards of 15 cfm per person. Outside air can also be used to cool the building using an economizer cycle. However, outside air dampers do leak, even when closed, and this degrades performance somewhat."


Excerpts from Energy-10 Help Files - All from Energy 10 Documentation.

First Time User

If this is your first experience with ENERGY-10, we suggest that before starting a complex building evaluation you first:

1.         browse through Welcome to Energy-10 in this Help.)

2.         open and study "Sample" (see Sample Building)

3.         work through the Exercises (see Exercises ).

4.         work through a simple problem (see Suggested Procedure).

Learn how to use ENERGY-10 Help! It takes the place of a user manual. Great effort has been expended to provide informative on-line, context-sensitive help. We know that many help programs are not very informative, but this one is different. Help is huge (about 79,000 words on 518 pages-- the largest file in Energy-10) but is highly cross-referenced and easy to navigate using handy hypertext.

You can access Help from the top-level menu or from any of the Help buttons on each of the dialog boxes. The latter displays a replica of the dialog box with "hot spots" (surrounded by dotted lines) that pop up a description of the relevant item. See: How to Use Energy-10 Help

There are three general ways that you can use ENERGY-10:

1.   Start from the beginning of a design. This is recommended.

1st: Read Use of ENERGY-10 in the Design Process.

2nd: Go through the steps in Suggested Procedure.

            You can do this with a project of your own.

2. Use ENERGY-10 to evaluate a building that is already well into design.

To do this, use ENERGY-10 as if you were starting from the beginning. Get the building description as close as you can, using the AutoBuild pre-design wizard (the automatic building-generation feature of ENERGY-10). Then modify the description of Bldg. 2 as needed to describe your building.

3 Use ENERGY-10 to evaluate a retrofit of an existing building.

To do this, use ENERGY-10 as if you were starting from the beginning. Get the building description as close as you

can, using the AutoBuild. Modify the description of Bldg. 1 as needed to describe your building. Then investigate retrofit options using Bldg 2.

Why Energy-10

AutoBuild

We have developed a way to define and evaluate a building before it has been designed. We call the process AutoBuild. The procedure is programmed into ENERGY-10 and can be done faster than we can explain it. The idea is that a Reference Case can be described based on only a few inputs--information that is available in the pre-design phase of a project. Three of these inputs are location, size (sq ft), and use category (office, warehouse, etc.). Additionally, you may have already fixed on the number of stories and choice of HVAC system. Starting from these five inputs, we can define and evaluate a building. We call this a Reference Case (you may wish to call it a "base case"-). It is a shoe-box design. At this early point in the design, a simple geometry is appropriate. In fact, in pre-design there is no design yet.

The next step is to do an energy analysis of your reference case. These results will be enlightening, especially if you are new to energy analysis. You find out how energy use and energy cost are divided between heating, cooling, lights, fans, and other uses, such as plug loads. The results are quantitative and graphic, as shown here. As you poke around in the output graphics, you can find how big the peak loads are and when they occur. Most importantly, you gain insight.

The AutoBuild wizard goes one step further. It generates not just one building description, but two. The second building is derived from the Reference Case. It is the same shoebox but with a potpourri of energy-efficient strategies applied. These might be added insulation, energy-efficient lights, daylighting, passive solar heating, and extra mass for heat storage (you get to select the strategies). This second building is called the Low-Energy Case. This building is also evaluated and the results displayed alongside the Reference Case results. (On the graphs, the two buildings are referred to as Bldg-1 and Bldg-2.) This gives you more information. It tells you the potential for savings from these strategies. Again, you can delve into the gory details to see just why and when the savings are being made.

Rank

An additional feature of ENERGY-10 is called RANK. RANK automates the process of sequentially applying several interesting energy-efficient strategies, evaluating their consequences, and ranking the results. We strongly suggest that you carry out these steps for each project right at the beginning. You obtain some guidance that can save time later on. You also go into preliminary design knowing the energy strategies that are likely to be most important in your building.

Making a Real Building

As you proceed through design, you will want to create a building description that represents the building that you are actually contemplating rather than the shoe-box generated by AutoBuild. You can do this starting from the Low-Energy Case. Just edit the building description. You may also want to edit the Reference Case to be a more suitable comparison building. ENERGY-10 carries both building descriptions through the whole process.

Where Info Stored

You can save your results and recall them later. Each project and all the design alternates that are associated with it are stored in the same directory.

Editable Info & Defaults

Throughout, ENERGY-10 is based on the principle that everything is defaulted and everything can be changed (including the defaults). This saves you time in setup yet gives you the greatest flexibility in defining the building. (See Defaults.) You can edit the libraries (material properties, glazing properties, wall constructions, etc.) on the fly, and you can save these modified libraries for later use, possibly in another project.

Getting Started – Step-by-Step

Starting a new design project? We suggest proceeding through the following steps.

1.         On the top-level menu of ENERGY-10, click File, then click New Project. (Alternatively just click the New Project icon--the one on the left.)

2.         Fill in all the blanks for Zone 1. If you want to know what something is, use Help. You might want to define a second zone to describe a different use category in part of the building.

3.         Click Project Data Sheet. Fill this in. Click OK.

4.         Now you are back in the Pre-Design Reference Building dialog box. Click OK. The AutoBuild wizard goes into action, calculating provisional data for your initial reference case building. The results are displayed on the next dialog box--Provisional Data.

5.         Edit the provisional data for Zone 1 (if needed). Click OK. (Do the same for Zone 2, if you specified one earlier.)

6.         An information screen will appear. Click Save and Simulate. Now the AutoBuild wizard goes into high gear. Two complete building descriptions are generated and now reside in the computer. The Save Project dialog box appears. Since you filled out the Project Data Sheet earlier, there is no need to do it now. Fill in the Project Directory (eight characters or less, no blanks or periods, no repeat names). Click OK. A new project directory is created and the building information is saved in this directory as Variant 001.

7.         The simulation of both buildings proceeds. This takes from a couple of minutes to many minutes, depending on your equipment. At the completion, a bar graph appears, showing the relative performance of both buildings. Simulation results have been saved automatically.

8.         Click Print. Click Print again. This sends the bar graph to your printer.

9.         Click Copy. The graphic is now resident in the Windows clipboard as a metafile. Without closing down ENERGY-10, switch to your word processor. Click Paste. The bar chart appears in your document. Switch back to ENERGY-10. (Now you know how to paste results into your reports.) Note that the metafiles can be edited in a drawing program.

10.       Take time to review several of the options under Reports. For example, have a look at Energy Use Graphs/Average Hourly Profiles, a particularly useful graphic. Also look at the Actual Hourly Profiles.

11.       While within Actual Hourly Profiles, click the H or the C button. Note how the plot jumps directly to the peak heating or cooling hour of the year. Locate the cursor on the scroll bar at the bottom of the graph and hold down the left mouse button. Note that the date appears at the left. While holding down the button, move left or right, noting the date change. Release the button; the plot jumps to the date indicated. Jump a week at a time forward or backward in time by just clicking in the scroll bar to the left or right of the box that denotes the current date. Click the + or the - button to change the number of days shown on the graph. Print a few graphs to show the client.

12.       Click EE Strategies on the top-level menu. Select Apply. Note which strategies were applied in the process of generating the low-energy case. (You can change these defaults right now by clicking on only those desired and clicking on the Save As Default button.)

13.       Click EE Strategies again; then click RANK. . Select two or three strategies or all the original strategies used. Now click RANK. The computer goes into heavy-duty simulation, one for each strategy selected. Go get a refill of coffee. Come back to see a bar chart that shows the saving for each strategy individually applied to the reference case. Try selecting other ranking criteria, such as Annual Operating Cost Savings.

14.       Go back to EE Strategies. Click APPLY. Select the top one or two strategies identified by RANK. Click APPLY. Now Bldg-2 is modified to use just the selected strategies. Perform a new simulation by clicking on the running man icon again. Review the results using Reports. Save As a New Variant (see How to…)

15.       Set some performance goals for the project, based on what you have learned so far. Now you are ready to start Preliminary Design on this building.

16.       As you design, modify the Bldg-2 description to reflect the actual dimensions of your building. As you proceed, save each design scheme as a new variant and simulate its performance, comparing the results with the original reference case. If you are not satisfied that the Reference Case is suitable, edit it too. You are in charge.

17.       Use the KEEP feature (the icon that looks like a key) to save the results of the each design scheme, including the two original buildings. Use the Keep Results feature (in Reports) to periodically assess how you are doing.

18.       When you are finished with Preliminary Design, go back through the building description, making sure that you have entered all the salient numbers for the selected design. Simulate one more time and check with the client to make sure that he or she is satisfied with the performance.

19.       Chalk one up for the good guys (or try again next time).

Projects & Variants

Saving Projects and Variants

ENERGY-10 provides a rigid framework for saving projects. When you save a new project, a separate directory is created on your hard disk. The first and all subsequent variants are saved to that same directory. You can specify the path to the directory when it is created. (Note, however, that you MAY NOT save the project as a sub-directory of an another project!) The default path is the directory where the ENERGY-10 program is stored. Each Save operation stores all information about a variant (except the library). This includes both Bldg-1 and Bldg-2 descriptions.

Maintaining the integrity of the project directory is essential because ENERGY-10 expects certain information to be located there, such as the KEEP file, the RANK file, and the results files. Normally the user doesn't need to be concerned about this because ENERGY-10 sets everything up correctly but if the user deletes or changes any of these files (for example by using the Windows File Manager), the program may not run or unexpected results may occur.

Note that your library may change as the design progresses, for example, if you modify a wall construction at some point. If you subsequently open a previous building description and then do a simulation, you may not get identical results because the library has changed.

HVAC Systems

List of HVAC Systems

(For more detail see HVAC System Descriptions)

HVAC System

HeatingCooling
System

Air
System

Distribution
System

Comment

Air Source Heat Pump/ER Backup

HP/ER Backup

A-A HP

Forced Air

Air-to-air heat pump with a reversing valve provides either heating or cooling. Distribution is by forced air through ducts. The electric-resistance backup operates when the compressor cannot meet the load. The compressor is turned off and the system is on electric resistance completely when the outside temperature is below the compressor lockout temperature. System can mix outside air with recirculated air and, properly controlled, can cool using unconditioned outside air (economizer cycle).

Baseboard Electric Heat

BB Electric

none

none

Heating only system using separate electric-resistance units. Heat is deposited directly into the conditioned space.

DX Cooling with Elect Furn

Electric Furnace

DX

Forced Air

Direct-expansion cooling unit combined with an electric-resistance furnace for heating. A ducted single-zone packaged rooftop or split system. System can mix outside air with recirculated air and, properly controlled, can cool using unconditioned outside air (if the economizer cycle option is enabled).

DX Cooling with Gas Furn

Gas Furnace

DX

Forced Air

Direct-expansion cooling unit combined with a fuel-fired furnace for heating. A ducted single-zone packaged rooftop or split system. System can mix outside air with recirculated air and, properly controlled, can cool using unconditioned outside air (if the economizer cycle option is enabled).

Gas-Fired Unit Heater

Gas/Radiant

none

none

Heat is discharged directly into the conditioned space.

Heat & Vent with Elect Furn

Electric Furnace

none

Forced Air

Heating only system using an electric-resistance coil. Distribution is by forced air through ducts. System can mix outside air with recirculated air and, properly controlled, can cool using unconditioned outside air (if the economizer cycle option is enabled).

Heat & Vent with Gas Boiler

Gas Boiler

none

Forced Air

Heating only system using a fuel-fired boiler. Distribution is by forced air through ducts. System can mix outside air with recirculated air and, properly controlled, can cool using unconditioned outside air (if the economizer cycle option is enabled).

Heat & Vent with Gas Furn

Gas Furnace

none

Forced Air

Heating only system using a fuel-fired furnace. Distribution is by forced air through ducts. System can mix outside air with recirculated air and, properly controlled, can cool using unconditioned outside air (if the economizer cycle option is enabled).

PTAC AA HP with ER Backup

HP/ER Backup

DX

Thru the Wall

either heating or cooling. The PTAC unit is mounted through the wall. Some systems can mix outside air with recirculated air. The electric-resistance backup operates when the compressor cannot meet the load. The compressor is turned off and the system reverts to electric resistance only when the outside temperature is below the compressor lockout temperature.

PTAC with ER BB Heat

BB Electric

DX

Thru the Wall

Packaged terminal air conditioner using a direct-expansion refrigerant cycle for cooling. The PTAC unit is mounted through the wall. Some systems can mix outside air with recirculated air. Heating is by separate electric-resistance units. Heat is deposited directly into the conditioned space.

PTAC with ER Heat

Electric Coil

DX

Thru the Wall

Packaged terminal air conditioner using a direct-expansion refrigerant cycle for cooling and an electric-resistance coil for heating. The PTAC unit is mounted through the wall. Some systems can mix outside air with recirculated air.

PTAC with Gas Boiler & HW Coil

Gas Boiler/HW Coil

DX

Thru the Wall

Packaged terminal air conditioner using a direct-expansion refrigerant cycle for cooling and a fuel-fired boiler for heating. Heat is transported from the boiler to a hot-water coil in the unit by a hydronic loop. The PTAC unit is mounted through the wall. Some systems can mix outside air with recirculated air.

Bugs in Version 1.3

Problems with the Current Release

At the time of release, the following issues remain. Work-arounds are suggested for each problem. All but the first two are carryovers from previous versions.

1.         Not Seeing Building-1 when resimulate

If you re-simulate Bldg-2, the plots will not show results for Bldg-1. When this happens, click the Swap Bdlg-1 and Bldg-2 button twice and then both graphs will show up properly. Use the same strategy if you Open a previously saved project in a Variant other than 001 and the plots do not show results for both buildings.

2.         Don’t switch programs while simulating

Energy 10 is not fully optimized for multitasking. Avoid switching to other programs while the thermal simulation is running. Switching or minimizing the thermal simulation might cause a "CNE server busy" message to occur.

3.            Glazing APPLY

The Glazing APPLY operation actually changes the whole window, not just the glazing. For a discussion of two work-around strategies, see Glazing APPLY.

4.            Variant ID

The variant number that appears on the third line of the Summary Page does not always display correctly when you Save as a New Variant. To make sure that the variant numbers shows correctly, click a building under Buildings on the menu, and exit with OK, the correct variant number will appear on the Summary Page.

5.            Variant Concept Confusing

The use of variants confuses users. Even the term is foreign. This will be fixed in Version 2, For now, we suggest that you learn the existing system, awkward as it is. It. will help to read Saving Your Work and Saving Project and Variants. Remember that a variant refers to the pair of Bldg.-1 and Bldg.2 building descriptions.

6.        

If a project is open and you want to either start a new AutoBuild or open another variant in the same project, it is first necessary to close ENERGY-10 and restart it. The message box says "Sorry. You will need to exit and re-start Energy-10 before opening another project". This was done to protect you from the possibility of a general protection fault or other unpredictable consequence. This problem has been observed infrequently since the first version. It will be corrected, but it was decided to use this temporary solution rather than delay the release of Version 1.3.

7.

If you Print a graphic, using the Black and White selection, the colors in the graph will be mapped to other colors before printing to produce a good contrast between the various colors on the screen. However, if you Copy a graphic, the graphic is saved to the Clipboard in color without this conversion. If you then Paste the graphic into a report and print it in black and white, the desired contrasts will not show (for example, both red and green print very dark). To correct this, you need to edit the graphic (using a vector graphic editor) selecting appropriate alternate colors. If you print in color, it will look fine. (It would have been preferable to provide the B&W mapping option on the Copy as well as the Print commands. This will be done in a future revision.)

8.        

The thermal simulation engine does not seem to work properly in the southern hemisphere. Solar angles are not calculated correctly. The temporary work-around for this is to evaluate the project as if it were in the northern hemisphere, shifting the weather data and the seasons by six months, and interpreting north as south and visa-versa.


Energy-10 Resources 

Last Updated: 10/6/2002