WARM UP #6: STRATEGIES


OBJECTIVES: In this warm up you will:

Learn about Energy Scheming:

  • specifying mass
  • solar zone icon
  • ordering strategies
  • scheduling
  • Advisor

Learn about energy:

  • thermal storage
  • strategy priorities


Learn about architectural design implications:

  • zoning for access to solar heating/cooling
  • sun capturing form
  • site response
  • orientation
  • thick envelopes


PROCEDURE:
1) Transfer a copy of the Warm up 6A file to your desktop.

2) Resize the internet browser window to a 2" wide narrow strip on the right hand side of the monitor.


3) Open the file Warm up 6A. This building file contains the Four Room House file you used in the tutorial. The climate has been set to Madison, the building type to residential, and the building size to 1200 sf. The Preferences have been set and the infiltration turned off. The file contains a full set of specs for the entire building.

4) Arrange the Energy Scheming and the internet browser windows so you can see them both.

5) Save the file as "(name) House No Mass".

6) Take a few minutes to become familiar with all the specs and takeoffs and schedules for this building.

7) Go to the graphic report and calculate. Change the scale on the graphic report to 1000.0 Btu (this is a correction so your graph will like the one above). And uncheck all evaluation days except March (make sure it is set to March Clear) so the graph looks like the thumbnail image above(remember clicking the thumbnail enlarges it)

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).


8) Heat gains and losses in this house for March are driven by:

primarily from the occupancy for gains.
primarily through the roof for both gains and losses.
primarily through the windows for both gains and losses.
primarily from the building enclosure (walls, roof, floor, and windows for losses.)



9) Save the file as "(name) House Mass".




10) To improve performance, we can try to store some of the gains in mass to use at night to offset the large losses. Add mass in the form of a slab floor. In the plan drawing, open the floor spec, click Select Floor Components button and set Mass to Solid 6".


11) Calculate and save.





12) We will concentrate on using mass for heating, and will look at March clear only. When you click on a bar of the graphic report, you get detailed information about that hour in a pop-up box. One of the portions of this box tells what strategies have been applied (assuming that the calculations are complete). The pop-up for the hour of Noon-1 pm for March clear is shown above. It indicates that external and internal shades were used to reduce the solar gains. This means that there is more solar gain possible for storing in mass, however the program is not storing heat in the mass.

13) There is another way to determine if our building needs mass for solar heating. Energy Scheming has a built-in expert system called the "advisor" which analyzes the graphic report and makes suggestions as to what might be done to improve the buildings performance.

14) Out of date. Please ignore this step. Go to the Advisor menu and make sure that the advisor is "on with balloons." If the advisor is off, you will have to recalculate to get advice.

15) Out of date. Please ignore this step. Also turn on thermographics from the View menu.

16) Out of date. Please ignore this step. There are two ways to get advice. If you are wondering how to improve a given building element, put your cursor on that element and an advice balloon will appear.


17) Or select Advise Window from the View menu.



18) The advisor organizes advice by importance and by building element. Advice in red is most important (can effect building energy use the most)

19) Click on the diamond in front of walls.



20) Out of date. Please ignore this step. Notice that the advice is the same as it was in the balloon we just looked at. The advice is the same whether you use a balloon or the list. However, the list form gives advice for the whole building and has more detail.

21) In the advisor, expand the section on mass.


22) Lets follow the advisor's recommendations by adding mass and south windows.

23) Open up the floor spec and select floor components.


24) Select mass solid 6". Also select the solar zone at the front of the icon.



If the front part of the solar zone is selected it means the mass and window are in the same room. If non-solar is selected it means the mass is in an adjacent room and solar heat is supplied to that room by heated air.

25) Note the floor spec now says "mass is solid 6 inches." Close the spec.




26) Select Energy Strategies from the Define menu. When Energy Scheming attempts to solve a heating or cooling problem, it looks to the strategies available. There are two lists for each of the four evaluation days. The first list includes all the cooling strategies and the second contains the heating strategies. Next to each strategy is a schedule bar. When Energy Scheming tries to cool a building, it uses the first cooling strategy listed. If there is still a cooling problem it moves to the next strategy and so on.

Examining the strategies for March clear, we see that Exterior shades are first, then Interior shades (the strategies apply to all operable shades provided they were specified in the window spec).

You may recall that Energy Scheming goes through the calculations twice. The first time it is calculating the net flow without considering strategies. It then recalculates by applying the strategies in an attempt to improve performance. Think back to when the current graphic report was being calculated and you may recall that there was a large solar gain present during the first pass calculations.




27) To utilize these gains click on the up arrow next to Loss to Mass in the cooling strategies. This moves causes it to switch places with the strategy next higher on the list. Continue moving Loss to Mass up until it is first. Now when Energy Scheming calculates it will first put excess gains into mass storage and then use the other strategies to balance loads. Note that Gain from mass is second under heating strategies. This is correct since we want to make this heat last as long as possible. Close the Energy Strategies window and bring the Graphic Report window to the front so you can see the change in the graph bars when you calculate.




28) Calculate and 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).


29) According to the March by element graph, performance would be improved if:

we set the thermostat to 55 at night when the occupants are asleep
more mass was added
more south windows were added
if there were decreased loss through the walls, roof, floor and windows

Doing "what-if"runs would be useful for making decisions on the first three answers. For the last answer use reasoning.

Check your answers against what the advisor says.


30) Click here if you would like to see the correct answers.



Go to:

Exercise #6A

Cool Down #6A

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