FIU Solar House’s Potential Performance: A Study of Natural Ventilation Strategies Cheng-Xian Lin and Long Phan Florida International University Miami, FL 33174

1 10 Contests Architecture Dwelling Documentation Communications Comfort Zone Appliances Hot Water Lighting Energy Balance 1 Getting Around Modular construction The house exhibition FIU Solar House’s demonstration An overview of the house All credits to DOE Solar Decathlon ( & FIU solardecathlon ( At a glance Name: Engawa Constructed by modules 1/3 glass PV-integrated windows (projection surface) Overall standing 13/18

10 Contests Architecture Market Appeal Engineering Communications Affordability Comfort Zone Hot Water Appliances Entertainment Energy Balance 1 Overview of the house model All credits to DOE Solar Decathlon ( & FIU solardecathlon ( Visitors at the exhibition in Washington D.C. Rooftop solar panels Aerial view Top view of the house model Exterior & interior 2 At a glance Name: perFORM[D]ance Modular design Open pavillion Operable louvers/shade Overall standing: 11/22

All credits to Solar Decathlon China ( & FIU-Tsinghua team( Interior 3 Overview of the house model Rooftop solar panels 3 10 Contests Architecture Market Appeal Engineering Communications Solar Application 3 Comfort Zone 1 Hot Water 1 Appliances Entertainment Energy Balance 1 At a glance Name: O-house Modular house PV louvers Traditional courtyard Overall standing: 5/22

 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 4

The Solar House Model  34’4” x 25’4” x 15’4”  7 typical residential spaces  Total conditioned area ft 2  Window-to-wall ratio is 45.8 %  Rooftop PV panels with tilted angle of 75 o 5 Floor plan of the house

 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 7

TotalNorthEastSouthWest Gross Wall Area (ft 2 ) Window Opening Area (ft 2 ) Gross Window-Wall Ratio (%) Room TypeArea (ft 2 )Volume (ft 3 ) Conditioned (Y/N) Electrical Load (W) Lighting Load (W/ft 2 ) Dining room ,297.11Y01.8 Living room ,869.21Y1, Bedroom ,869.21Y Bathroom Y5, Study room Y601.8 Kitchen ,655.90Y8, Battery room N-- Mechanical room 30.10N -- 8 Typical rooms of the solar house The 2005 solar house model Wall and window areas in different surfaces

Energy Balance Equation for a room model Net Zone Load System Load Equation 9 Simulation Code: EnergyPlus

Int. DoorExt. Door Ext. WindowsRoofFloorExt. WallInt. Wall Layer 1Wood Metal surface Clear glass Plywood Metal surfaceCellular Polyisocyanurate - Gas permeable facers Gypsum board Layer 2 Insulatio n board Air resistance Polystyrene (Extruded) Polystyrene (Extruded) Steel frame Layer 3 Clear glass Steel framePolystyrene (Molded beads) Polystyrene (Molded beads) Polystyrene (Molded beads) Layer 4 Polystyrene (Molded beads) Steel frameGypsum board Layer 5 Gypsum boardPlywood Miami, FL climate graph 10

(a) (b) (c) Natural ventilation methods (a)Thermal chimney (TC) (b)Earth tube (ET) (c)Cool tower (CT) (d)Opening 11 (d)

(a) Annual energy consumption(b) Total uncomfortable days Comparison among various natural ventilation systems 12

Comparison among various hybrid cooling systems (a) Annual energy consumption(b) Total uncomfortable days Hybrid system schedule 13

Comparison among all cooling systems 14

15 Temperature profile of 7 thermal zones at different cooling strategies

 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. 16