CBMA Kohler

Slide1: 

Christian Kohler (CJKohler@lbl.gov) Lawrence Berkeley National Laboratory Highly Insulating Windows & Software Tools October, 2007

Goals for Highly Insulating Windows: 

Goals for Highly Insulating Windows Windows that gain as much heat from the sun as they lose.

Defining Zero Energy Windows: 

Defining Zero Energy Windows Zero Energy Windows have a net-zero annual energy balance Approach: Model “standard houses” in 5 different locations Vary windows from very insulating to very bad Vary windows from high solar gain to low gain Plot the results in a graph

Performance Goals: 

Performance Goals More solar gain More Insulating

Minneapolis: 

Minneapolis

Non-structural center-layers: 

Non-structural center-layers Current technologies for highly insulating products use multiple layers of low-e and gas fill All glass is heavy Thin film products expensive Multiple spacers can lead to gas leakage LBNL research aims to develop lower-cost, non-structural center layers Utilize available low-e and gas-fill technologies Research novel center layer designs and materials

Non-structural center-layers:: 

Non-structural center-layers: Acrylic center layer Plastic layer

FY07: Non-structural center-layers:Thin glass: 

FY07: Non-structural center-layers: Thin glass Very thin glass (e.g. .7mm) is now available in large sizes as a result of LCD and Plasma TV markets Prices are falling rapidly as volume increases Samples recently received from Corning IGs to be built in ’08 Will center layers bow? – depends on how they are positioned Cost and Handling issues? 3 mm (0.118”) 1.1 mm (0.043”) 0.7 mm (0.028”)

Prototype Testing Results:Simple insert performs as well as fixed layer: 

Prototype Testing Results: Simple insert performs as well as fixed layer

Slide10: 

Software Tools

Modeling : 

Modeling

Slide12: 

Software Tools

Chinese version of WINDOW6: 

Chinese version of WINDOW6

Slide14: 

Thank you. Christian Kohler Windows and Daylighting Research Group CJKohler@lbl.gov

FY07: Non-structural center-layers:Structural Issues: Acrylic: 

FY07: Non-structural center-layers: Structural Issues: Acrylic CYRO, leader in production and development of acrylic for fenestration products, is supplying us with various types of acrylic sheet to better understand which type of acrylic sheet is suited to center-layer applications

Heat Transfer through Windows: 

Heat Transfer through Windows Conduction (conv+rad in cavities) Radiation Conduction Convection Low-e coatings Special gas fills Multiple cavities Low conductance spacers Better frames Primary Driver: Indoor/outdoor temperature difference

FY07: Non-structural center-layers:Spacers and sealants: 

FY07: Non-structural center-layers: Spacers and sealants Super spacer, Swiggle-strip grooves for 3 layer design used in prototyping New BASF TPS technology; BASF visit to LBNL and continued discussions

Non-structural center-layers – FY08: 

Non-structural center-layers – FY08 Resolve issue of why acrylic layers deflect and determine what if any “upgrades” are needed Field-expose (at LBNL) samples Understand potentials of thin glass Continue/expand contacts with industry to explore cost, availability, business issues Window and IG manufacturers Spacer manufacturers Production Equipment manufacturers

FY07: Low-conductance Frame Heat Transfer : 

FY07: Low-conductance Frame Heat Transfer For residential sized windows (6-10 sf total) the frame is 20-30% of area and thus a critical element of a high R window Little experience in the U.S. with highly insulating frames Turn to Europe for Review of European low-conductance frames How do we assess actual performance of a low-conductance frame? (see related Software Tools effort)

FY07: Low-conductance Frame Heat Transfer: Review of European frames: 

FY07: Low-conductance Frame Heat Transfer: Review of European frames Driven by Passivhaus requirement U< 0.8 W/m2-C (.14 IP) Literature review in collaboration with Arild Gustavsen, Norway Two themes More highly insulating frames Lower profile frames to capitalize on solar gains

Low-conductance Frame Heat Transfer: Insulating European frames: 

Low-conductance Frame Heat Transfer: Insulating European frames Wood Frame with PUR

Low-conductance Frame Heat Transfer: Insulating European frames: 

Low-conductance Frame Heat Transfer: Insulating European frames Wood Frame with Insulation Filled Al cladding

Low-conductance Frame Heat Transfer:FY08 plans: 

Low-conductance Frame Heat Transfer: FY08 plans Analysis of methods used in European frames Use/positioning of thermal breaks, cavities Hardware impacts Spacer impacts Analysis of other issues low emittance cavities phase change frames Testing IR (LBNL) Hot box (Norway) Performance issues (see Tools work; multi-year effort not currently funded) Continued collaboration with A. Gustavsen

Field Tests: 

Field Tests Objectives Document field energy performance and non-energy benefits of today’s highly insulating windows Improve homebuilders’ familiarity with highly insulating windows Generate manufacturer interest in applications Projects Field demonstrations in Building America test houses Installation and monitoring of highly insulating windows vs. standard ENERGY STAR in collaboration with Cardinal IG in identical houses in Ft. Wayne, Indiana

Low-Energy Home Demonstration – FY07: 

Low-Energy Home Demonstration – FY07 Affordable home in MA (CARB Building America team) Heat Mirror (U=0.2) windows provided by builder’s normal supplier at no price premium Typical price premium strongly related to special order process Compared window-surface temperatures against baseline windows

Interior Surface Temperatures: 

Interior Surface Temperatures Heat Mirror Double, clear

Cardinal Test Houses - Indiana: 

Standard low-solar gain low-e vs. triple-pane with high-solar gain and insulated frames (U<.2) Side-by-side houses have been monitored, empty, since Jan 2007 Prior year’s data on typical Energy Star windows also available Cardinal Test Houses - Indiana