FIU Solar House’s Potential Performance:
A Study of Natural Ventilation Strategies
Cheng-Xian Lin and Long Phan
Florida International University
Miami, FL 33174
10 Contests
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Architecture
Dwelling
Documentation
Communications
Comfort Zone
Appliances
Hot Water
Lighting
Energy Balance1
Getting Around
Modular construction
An overview of the house
At a glance
Name: Engawa
Constructed by modules
1/3 glass
PV-integrated windows
(projection surface)
• Overall standing 13/18
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FIU Solar House’s demonstration
The house exhibition
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All credits to DOE Solar Decathlon (www.solardecathlon.gov) & FIU solardecathlon (http://gsl.eng.fiu.edu/webs/SOLAR2004/)
10 Contests
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Architecture
Market Appeal
Engineering
Communications
Affordability
Comfort Zone
Hot Water
Appliances
Entertainment
Energy Balance1
Aerial view
Overview of the house model
At a glance
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Visitors at the exhibition in
Washington D.C.
Rooftop solar panels
Name: perFORM[D]ance
Modular design
Open pavillion
Operable louvers/shade
Overall standing: 11/22
Exterior & interior
Top view of the house model
All credits to DOE Solar Decathlon (www.solardecathlon.gov) & FIU solardecathlon (www.solardecathlon.fiu.edu)
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10 Contests
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Architecture
Market Appeal
Engineering
Communications
Solar Application3
Comfort Zone1
Hot Water1
Appliances
Entertainment
Energy Balance1
At a glance
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Overview of the house model
Name: O-house
Modular house
PV louvers
Traditional courtyard
Overall standing: 5/22
Interior
Rooftop solar panels
All credits to Solar Decathlon China (http://www.sdchina.org/) & FIU-Tsinghua team(http://www.thfisdc.com/)
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 Public Exhibition and Educational Activities
 Outreach: Annual Engineering Expo, Engineers on Wheel
 Visiting by students: undergraduate and K-12
 Lab tours
 Student Projects
 Senior design projects
 Course projects
 Exchange student studies
 Elise Belleil, EI. CESI, France, Summer 2013
 Francisco Zevallos, Loughborough/Northumbria University, UK, Fall 2013
 Research Projects
 Real time temperature and humidity monitoring
 PV/T technology demonstration
 Building energy simulation model validation
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The Solar House
Model
 34’4” x 25’4” x 15’4”
 7 typical residential
spaces
 Total conditioned area
721.15 ft2
 Window-to-wall ratio is
45.8 %
 Rooftop PV panels with
tilted angle of 75o
Floor plan of the house
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 The benefits of natural ventilation strategies
 The limitations and remedies of energy utilization in hot and humid
climates
 The aid of building energy simulation program providing insights for
different strategies
 Comparisons of a few natural ventilation strategies to seek the most
possible solution in terms of thermal comfort and energy reduction
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Wall and window areas in different surfaces
(ft2)
Gross Wall Area
Window Opening Area
(ft2)
Gross Window-Wall
Ratio (%)
Total
1682
North
500.41
East
449.18
South
283.09
West
449.18
764.99
360.59
202.25
0
202.25
45.48
72.06
45.03
0.00
45.03
Typical rooms of the solar house
Room Type
Area (ft2)
Volume (ft3)
Dining room
Living room
Bedroom
Bathroom
Study room
Kitchen
Battery room
Mechanical
room
120.56
135.63
135.63
78.79
88.48
162.43
19.48
1,297.11
1,869.21
1,869.21
718.30
986.34
1,655.90
30.10
407.53
Conditioned
(Y/N)
Y
Y
Y
Y
Y
Y
N
N
Electrical
Load (W)
0
1,050
840
5,340
60
8,964
-
Lighting Load
(W/ft2)
1.8
1.8
1.8
1.8
1.8
1.8
-
The 2005 solar house model
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Energy Balance Equation for a room model
𝑑𝑇𝑧
𝐶𝑧
=
𝑑𝑡
𝑁𝑠𝑢𝑟𝑓𝑎𝑐𝑒𝑠
𝑁𝑠𝑙
𝑄𝑖 +
𝑖=1
𝑁𝑧𝑜𝑛𝑒𝑠
ℎ𝑖 𝐴𝑖 𝑇𝑠𝑖 − 𝑇𝑧 +
𝑖=1
𝑚𝑖 𝐶𝑝 𝑇𝑧𝑖 − 𝑇𝑧 + 𝑚𝑖𝑛𝑓 𝐶𝑝 𝑇∞ − 𝑇𝑧 + 𝑄𝑠𝑦𝑠
𝑖=1
Net Zone Load
𝑁𝑠𝑢𝑟𝑓𝑎𝑐𝑒𝑠
𝑁𝑠𝑙
𝑄𝑙𝑜𝑎𝑑 =
𝑄𝑖 +
𝑖=1
𝑁𝑧𝑜𝑛𝑒𝑠
ℎ𝑖 𝐴𝑖 𝑇𝑠𝑖 − 𝑇𝑧 +
𝑖=1
𝑚𝑖 𝐶𝑝 𝑇𝑧𝑖 − 𝑇𝑧 + 𝑚𝑖𝑛𝑓 𝐶𝑝 𝑇∞ − 𝑇𝑧
𝑖=1
System Load Equation
𝑄𝑠𝑦𝑠 = 𝑚𝑠𝑦𝑠 𝐶𝑝 𝜂 𝑇𝑠𝑢𝑝 − 𝑇𝑧,𝑑𝑒𝑠𝑖𝑟𝑒𝑑
Simulation Code: EnergyPlus
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Miami, FL climate graph
Int. Door
Layer 1
Layer 2
Layer 3
Layer 4
Layer 5
Wood
Ext.
Door
Metal
surface
Ext. Windows
Roof
Floor
Ext. Wall
Int. Wall
Clear glass
Plywood
Metal surface
Gypsum board
Insulatio
n board
Air resistance
Polystyrene
(Extruded)
Steel frame
Polystyrene
(Extruded)
Polystyrene
(Molded beads)
Cellular
Polyisocyanurate Gas permeable
facers
Steel frame
Polystyrene
(Molded beads)
Polystyrene
(Molded beads)
Gypsum board
Steel frame
Polystyrene
(Molded
beads)
Gypsum board
Clear glass
Plywood
Gypsum board
Steel frame
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(b)
(a)
Natural ventilation methods
(a)
(b)
(c)
(d)
(c)
Thermal chimney (TC)
Earth tube (ET)
Cool tower (CT)
Opening
(d)
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(a) Annual energy consumption
(b) Total uncomfortable days
Comparison among various natural ventilation systems
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Hybrid system schedule
Comparison among various
hybrid cooling systems
(a) Annual energy consumption
(b) Total uncomfortable days
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Comparison among all cooling systems
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Temperature profile of 7 thermal zones at different cooling strategies
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 Various natural ventilation strategies including earth tube, thermal chimney, wind
tower, and opening, as well as hybrid strategies are investigated.
 Relying on only natural ventilation could cause a dramatic impact to the human
thermal comfort.
 Hybrid systems have revealed the significant reduction in cooling energy
consumption while complying with the minimum requirements for thermal comfort
recommended by ASHRAE standards.
 Combined thermal chimney and mechanical system (HVAC) method shows
relatively better potentials for hot and humid climate such as Miami.
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