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UNDERGRADUATE ARTS + HUMANITIES College of Arts, Media, and Design Bachelor’s of Arts in Architecture Abstract ID #210 PRESENTED PROBLEM Located in Phoenix, Arizona, the site presented many challenges in the design of an environmentally concious residence. When designing with passive systems, it is important to understand where the most effective application of such moves can be most beneficial. The first step was to research how the natural conditions of Phoenix would affect the systems that we would employ, to maintain an energy effecient home. The hot, dry climate requires an emphasis on cooling strategies during the day, but the temperature often drops off at night, requiring some heat-retention strategies as well. Below are two icons which we developed as a jumping point from which to better understand how to apporach this design.

RESEARCH IN ENERGY MODELING AND SUSTAINABLE DESIGN

PHOENIX PAVILION KYLE BIRCHALL | JOSE LATORRE | ACADEMIC ADVISOR | SETH HOLMES

The “overheated” period in Phoenix, Arizona represents the greatest portion of the days that fall out of the original comfort zone for the climate.

Most temperatures during the “under heated” period of the year in Phoenix fall well within the comfort zone of an average human, and never approach 32° F.

Therefore, the most attention should be paid to improving the conditions during this period.

The best passive technique is to live according to your climate ADAPT!

PROJECT ABSTRACT A hot-button topic at Northeastern University is the “go-green” phenomenon, which raises questions regarding how we treat the world in which we live. Although sustainability is an issue that has global implications, it is nonetheless one that can be confronted at the micro-scale. Currently, the construction and maintenance of our buildings is accountable for 48% of global carbon dioxide emissions. This includes not only the heating and cooling costs and the embodied energy released by moving materials to a site, but also the performance of those materials once the building is finished. As architecture students, we realize that the onus is on us to make choices to ensure that our buildings can be part of a future, rather than the ruins of a past. A recent Environmental Systems class began to show us ways to make these environmentally conscious choices throughout the design process. During the semester we faced weekly challenges regarding the design of the different systems of a “sustainable” house, sited in Phoenix, Arizona. The final investigation was the use of energy-modeling simulations, which allow the architect to understand the effectiveness of their design, and help guide decisions made regarding material choices and HVAC systems. Despite only an experimentation with these programs, the results were promising and verified that the house functioned as intended. I believe a longer exposure to energy simulators such as DesignBuilder would result in significantly more sustainable designs, not only in my work, but for the entire Northeastern Architecture program altogether.

ARCHITECTURAL DRAWINGS

DESIGN DIAGRAMS

EAST ELEVATION

SOUTH ELEVATION

NORTH ELEVATION

WEST ELEVATION

PHOTOVOLTAIC PANEL STUDY

39

PANELS

DAY hot/dry air is not allowed into the building

NIGHT cool/dry air purges heat and ventilates

DAY cooling tower draws hot air out stratification

NIGHT air flow removes heat gained by slab during the day and purges it

X39

11.7 KW

COOLING TOWER raised ventilation tower is aligned with the prevailing winds during te summer months, and allows augmented natural ventilation, in combination with an indrect cooling membrane. SUN BLOCKING CANOPY all south-facing overhangs extend to ensure that during the hottest months, no direct sunlight will enter the structure, while also allowing sunlight to penetrate during the winter. SECONDARY CROSS VENTILATION operational/moveable system that allows for a proper cross ventilation that would facilitate the cooling of the structure during the night (night purge). ideally not operational during the day when the cooling tower would be in effect because it would deviate the hot air from accumulating in the tower. FLOOR PLANS 30

PSYCHOMETRIC CHART & PASSIVE STRATEGIES STUDY AH

30

25

20

15

10

5

DBT(°C)

5

10

15

20

25

30

35

40

45

50

“2H” rule: H taken at 20’

“15, 30” diagram darker yellow indicates the “adequately” daylighted zone (15-30 feet)

SOLAR ORIENTATION STRATEGY AND DESIGN

the psychometric chart helped inform early decision on the design agenda and strategies. the study resulted on a reinterpretation of the way in which the passive strategy’s effectiveness on expanding the comfort zone of a determined space is read in the psychometric chart - the comfort percentage scale. knowing the most effective strategies on helping accomplish the early objectives of the project prevents design decision that are not the best possible and creates a more comprehensive design overall.

N

345°

15°

330°

30° 10°

315°

45°

20° 30°

300°

time

solar

JULY21

10

12:00 (11:28) 12:30 (11:58) 13:00 (12:28)

DEC21

5

12:00 (11:34) 12:30 (12:04) 13:00 (12:34)

azimuth altitude

144.0° 177.9° -147.1°

77.6° 79.7° 77.9°

172.9° -178.9° -170.7°

32.7° 33.0° 32.5°

60° 40°

1st Jun

1st May 285°

1st Jul

50°

1st Aug

60°

75°

70°

1st S ep

80°

1st Apr 270°

90° 1st Oct

1st Mar 255°

1st105° Nov

1st Feb 1st Dec

1st Jan 240°

17

16

15

14

13

12

11

10

8

9

225°

120°

135°

210°

150° 195°

11.7 kW DC rating .770 DC to AC derate factor 9.0 kW AC rating FIXED TILT Array type 18.5 Array Tilt 180 Array Azimuth 8.5 cents/kWh Electricity cost

15.4 years

THERMAL MASSING STRATEGY by burying the structure deep into the earth and using concrete walls + roof, we can ensure that the maximum amount of thermal heat is absorbed, and then released during a night purge.

NORTH - SOUTH SECTION

18,498 YEARLY kW h

“15, 30” diagram darker yellow indicates the “adequately” daylighted zone (15-30 feet)

PREVAILING WINDS STRATEGY AND DESIGN

the main goal is keeping direct sunlight outside during the hot months. an operational porch roof allows sunlight inside during the winter. the cooling tower works as a clerestory for winter light. main roof inclinations and overhangs were determined by two sample moments in the year (July 21, December 21).

345°

NOR T H

50 km/ h

15°

345° 30°

ENVIRONMENTAL SYSTEMS PRIORITIES

following the idea of night purge and natural ventilation, the prevailing winds on site were studied. the most regular wind orientations where grouped and the orientations (degrees) where averaged, both, the yearly data, and July’s (hottest month) data, to finally come up with an appropriate 20 degree rotation angle in plan to collect the best winds for the desired passive systems. prevailing wind information could potentially further inform the design of the vents that serve the night purge system.

hrs

15°

330°

30°

40 km/ h

37 33

40 km/ h

315°

45°

315°

29

45°

30 km/ h

25 21

30 km/ h

16 300°

60°

300°

60°

20 km/ h

12 8

20 km/ h

<4 285°

75°

285°

75°

10 km/ h

10 km/ h

W EST

E AS T

255°

105°

240°

120°

225°

135°

210°

W EST

E AS T

255°

105°

240°

120°

225°

150° 195°

S OUT H

prefered orientation (year)

135°

210°

165°

165°

180°

NOR T H

50 km/ h

42+ 330°

150° 195°

165°

S OUT H

prefered orientation (july)

ENERGY MODELING DATA (using DesignBuilder)

COMFORT PERCENTAGE SCALE (monthly) before after

0%

TEST 1:

100%

THERMAL MASS + NIGHT PURGE

mechanical ventilation 24-hour mechanical cooling

TEMPERATURE (Fahrenheit)

INDOOR

80

JAN

DEC

most effective passive strategy. effective in both winter and summer. material changed (concrete) and massiveness of the structure was increased to allow for heat sink and night purge. use of natural ventilation to allow for proper night purge is allowed with secondary cross ventilation. burrying the structure in the slope allows for better insulation, still the thick slab that roofs the double height space works as a thermal mass for the structure.

60 APRIL

JULY

night purge vetilation (10pm - 4 am) mechanical cooling (4am - 10pm)

AVG. AMBIENT TEMP:

exterior in july: interior in july:

OUTDOOR

100

40

SELECTED METHOD:

OCTOBER

ENGERY CONSUMPTION (kBTU)

98° 78°

exterior in december: interior in december:

140

120

TEMPERATURE COMPARISON with selection

100

80

60

40

20

0

DEC

JAN

NATURAL VENTILATION not the most effective passive strategy, but it is indispensable for a proper thermal mass/night purge strategy. the plan was rotated 20 degrees by averaging the angle of prevailing winds from the whole year with the data of July (least comfort zone month). the secondary ventilation screen system provides proper cross ventilation to the double height space. the screens (on the East and West facades of the structure) would be open to allow the night purge of the building mass, but closed during the day so that the cooling tower could function to its best performance.

TEST 2:

OCTOBER

night purge vetilation (10pm - 4 am) mechanical cooling (4am - 10pm)

TEMPERATURE (Fahrenheit)

INDOOR

OUTDOOR

80 60 APRIL

JULY

OCTOBER

ENGERY CONSUMPTION (kBTU)

JAN

DEC

second most effective passive strategy. indirect cooling tower is applied in the structure to effectively apply inderect evaporative cooling. hot air would rise and end up accumulating in the cooling tower which has been designed with screens that allow proper air circulation to drive the hot air outside. the secondary (operational) ventilation screen does not interfer with this system since it would be used for night purge only (or when extreme windy conditions make cross ventilation more effective than indirect evaporative cooling). PASSIVE SOLAR HEATING

not the most effective passive strategy. sun must be a driver of design even if it is not the must effective strategy. the operational roof structure in that covers the porch was desgned with the proper angles that allow winter sunlight in, and keep sun outside the rest of the year. the overhang of the mezanine follows the intent of allowing winter sunlight inside as much as possible. the cooling tower becomes a hybrid, it also works as a clerestory, designed to allow the must winter light inside, and thus, solar radiation. direct solar “cooling” - thinking ahead (in active systems) the massive roof over the double height space follows a 18.5 degree angle that corresponds to the angle PVs must follow for the optimal sun recolection for solar cooling.

ENERGY USE COMPARISON with selection

140

120

100

80

60

40

20

0

TEST 3:

DEC

JAN

JULY

100

40

INDIRECT EVAPORATIVE COOLING

APRIL

APRIL

JULY

OCTOBER

night purge vetilation (10pm - 4 am) mechanical cooling (10am - 10pm)

TEMPERATURE (Fahrenheit)

INDOOR

100 80 60 40

APRIL

JULY

OCTOBER

ENGERY CONSUMPTION (kBTU) 140

120

100

80

60

not as effective as indirect cooling. not considered in any of the strategies followed in the structure if needed strategies could be followed.

40

DEC

JAN

DIRECT EVAPORATIVE COOLING

20

0

APRIL

JULY

OCTOBER

OUTDOOR

55° 75°


RISE 2012