6) Heat gains and losses in this community center for all four months are driven by:

A) primarily from the occupancy in the auditorium (gains) and from the building enclosure (walls, roof, floor, and windows (losses).
B) primarily through the roof for both gains and losses.
C) primarily through the windows for both gains and losses.
D) primarily from the occupancy in the office (gains) and from the building enclosure (walls, roof, floor, and windows (losses).




7) Often a building will contain spaces that requires mostly cooling and spaces that requires heating. Separate conditioning systems would service each space, whether conventional HVAC or passive. In Energy Scheming , each space would be modelled separately. For example,the heating and cooling needs of the auditorium of the community center is different from the office and lobby. We will now look at each space separately.

8) Transfer a copy of Exercise 6A Office/Lobby to your desktop and open it.

9) This file contains only the office and lobby space of the community center. The portions of the walls, floor, roof, lighting and occupant takeoffs that were associated with the auditorium were removed. Make sure that the Evaluation Days are set to: Mar Clear, Jun Clear, Sep Clear, and Dec Clear (Climate floating palette found when you bring up the Graphic Report window)



10) Go to the Graphic report and calculate, and note the difference.



11) Next deselect June and September from the climate day list, so that only March and December are visible. Change the scale to 4000 BTU.


Question

Please answer the following question using the graphic report:
(More than one answer may be correct, but extraneous answers will be considered incorrect. For example if two answers are correct, and you mark only one, the answer is incorrect. If you marked three, including the two correct answers, the answer is incorrect).


12) Strategies for reducing the heating load (total netflow bars below the zero line) in the Office/Lobby for March and December include:

A) removing the windows.
B) removing the carpet and using the slab floor as mass.
C) changing the windows to fixed to stop excess heat from exiting via cross ventilation.
D) schedule people to work at night.


13) Save the file as "(name) Comm Ctr Office/Lobby".




14) We will use mass as a heating strategy. Mass can absorb excess heat during the day and release it at night to offset the heat loss. In the plan, open the floor spec. Remember that you can change the number of takeoffs displayed by going to Takeoffs... under the View menu.




15) Change the floor spec to have solid 6" of mass in the Components dialogue box. The floor finish was carpet originally. Since we are changing the floor to act as thernal mass we need to specify a material which will not resist heat flow in and out of the concrete. Energy Scheming does not check whether the floor finish will permit the concrete below it to act as mass, so as the designer, you need to account for this. Change the interior floor finish to quarry tile.




16) Change the icon name from Carpet to QuarryTile.

17) Under the Define menu, select Energy Strategies, and move Loss to Mass to the top of the cooling strategies for March and December. This instructs Energy Scheming to store heat in the mass before venting it.

18) Calculate and print the By element and total net flow graphs. Save. Your graphs should look like this illustration below.

Question

Please answer the following question using the graphic report:
(More than one answer may be correct, but extraneous answers will be considered incorrect. For example if two answers are correct, and you mark only one, the answer is incorrect. If you marked three, including the two correct answers, the answer is incorrect).

19) The By element and Total net flow graphs for Comm Ctr Office/Lobby show that:

A) adding more mass would further reduce the heating load in December and March.
B) shading windows would further reduce the heat loss in December and March.
C) a combination of stack and cross ventilation would further reduce the heat loss in December and March.
D) there is no heat loss for December and March.


20) Additional mass may be added either as part of a wall or roof specification, or as a specification separate from the building enclosure.

21) Close the file.

22) Transfer a copy of Exercise 6A Auditorium to your desktop.

23) Open the file "Exercise 6A Auditorium" and save as "(name) Comm Ctr Auditorium".

24) This file contains only the auditorium of the community center. The portions of the walls, floor, roof, lighting and occupant takeoffs that were associated with the office and lobby were removed. Make sure that the Evaluation Days are set to: Mar Clear, Jun Clear, Sep Clear, and Dec Clear (Climate floating palette found when you bring up the Graphic Report window)




25) Calculate. The graphs show that the auditorium is an internal load dominated building. We will use mass as a cooling strategy, to absorb heat during the day and release the heat when the temperature is cool enough to ventilate the mass (night ventilation of mass cooling).


26) Change the floor spec to have solid 6" of mass in the Components dialogue box. Change the interior floor finish to quarry tile.

27) Under the Define menu, select Energy Strategies, and make sure Loss to Mass is at the bottom of the cooling strategies for all four months.




28) Next we will add stack ventilation. Open a new window specification in the south elevation. Click Detailed WindowDesign button. Three windows will appear. Set the Window Plane screen as shown above, with 100% operable, zero SHGC and zero visible transmission. Close all three windows. Schedule cross ventilation off for all days.




29) Take off the lower vents in the south elevation. Select the stack icon. A pop-up window will come up asking you to draw a reference line. Close this window by clicking the OK button. The cursor will change to a beach ball icon. Drag your mouse in a horizontal direction on the drawing at the ground plane(below any of the windows) to create a reference line. Next select Inlet radio button in the window spec.

Note: the reference line is used by the program to figure stack height. To create accurate stack heights, the reference line should be at the same relative place (eg. the ground line of each elevation) on the drawing and the windows should be placed in reference to this line. The program calculates the stack height from this line to the top of each window.




30) Next create a similar window specification in the north elevation, with 100% operable, zero SHGC and zero visible transmission. All other values can stay the same. Make sure that the reference line is in approximately the same place as the one created for the south elevation window. Using the Rule of Thumb Window Sizer, takeoff the turbine ventilators in the north elevation, and add additional area until the stack vent outlet approaches 100%.


31) Calculate and print the By element and total net flow graphs for September Clear only. Save.




Question

Please answer the following question using the graphic report:
(More than one answer may be correct, but extraneous answers will be considered incorrect. For example if two answers are correct, and you mark only one, the answer is incorrect. If you marked three, including the two correct answers, the answer is incorrect).


32) What is the minimum size of 8" solid concrete mass that must be added to totally eliminate the heat gain and loss in September? (use duplicating tool next to tape measure, if you like. Double means duplicating once. 4x's means duplicating 3 more takeoffs for an area 4x's the original size, etc.)

A) 2x's the floor area
B) 4x's the floor area
C) 6x's the floor area
D) 8x's the floor area


33) What will improve the performance of the auditorium in March Clear and December clear? (do not test additively but test one at a time)

A) Move loss to mass to the top of the strategies to store excess heat in the mass to offset the heat loss at night.
B) Remove the mass and replace with carpet.
C) Reduce the minimum thermostat setting to 55 degrees when the building is unoccupied.
D) Increase the activity level to moderate dancing.

Comments:

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