00858nas a2200133 4500008004100000050001500041245006800056210006800124300001100192490000700203520041500210100002200625856007700647 1999 eng d aLBNL-4282500aNet Energy Performance Measurements on Electrochromic Skylights0 aNet Energy Performance Measurements on Electrochromic Skylights a93-1020 v333 a

Tests of skylights made from prototype electrochromic glazings were performed in a room-sized calorimetric test facility under ambient outdoor summer conditions in Reno, NV. The test methodology and the resultant measurements of skylight heat flows and temperatures with their diurnal variations are presented. Special test issues relating to the dynamic switchable nature of the glazings are discussed.

1 aKlems, Joseph, H. uhttps://facades.lbl.gov/publications/net-energy-performance-measurements01903nas a2200133 4500008004100000050001400041245014300055210006900198260002800267490001600295520136000311100002201671856007601693 1993 eng d aLBL-3471500aA New Method for Predicting the Solar Heat Gain of Complex Fenestration Systems I. Overview and Derivation of the Matrix Layer Calculation0 aNew Method for Predicting the Solar Heat Gain of Complex Fenestr aNew Orleans LAc01/19940 v100, Part 13 a

A new method of predicting the solar heat gain through complex fenestration systems involving nonspecular layers such as shades or blinds has been examined in a project jointly sponsored by ASHRAE and DOE. In this method, a scanning radiometer is used to measure the bidirectional radiative transmittance and reflectance of each layer of a fenestration system. The properties of systems containing these layers are then built up computationally from the measured layer properties using a transmission/multiple-reflection calculation. The calculation produces the total directional-hemispherical transmittance of the fenestration system and the layer-by-layer absorptances. These properties are in turn combined with layer-specific measurements of the inward-flowing fractions of absorbed solar energy to produce the overall solar heat gain coefficient. In this first in a series of related papers describing the project, the assumptions and limitations of the calculation method are described and the derivation of the matrix calculation technique from the initial integral equations is presented.

In this first in a series of related papers describing the project, the assumptions and limitations of the calculation method are described and the derivation of the matrix calculation technique from the initial integral equations is presented.

1 aKlems, Joseph, H. uhttps://facades.lbl.gov/publications/new-method-predicting-solar-heat-001572nas a2200121 4500008004100000024001100041245014100052210006900193490000800262520108200270100002201352856007601374 1993 eng d aDA-32100aA New Method for Predicting the Solar Heat Gain of Complex Fenestration Systems II. Detailed Description of the Matrix Layer Calculation0 aNew Method for Predicting the Solar Heat Gain of Complex Fenestr0 v1003 a

A new method of predicting the solar heat gain through complex fenestration systems involving nonspecular layers such as shades or blinds has been examined in a project jointly sponsored by ASHRAE and DOE. In this method, a scanning radiometer is used to measure the bi-directional radiative transmittance and reflectance of each layer of a fenestration system. The properties of systems containing these layers are then built up computationally from the measured layer properties using a transmission/multiple-reflection calculation. The calculation produces the total directional-hemispherical transmittance of the fenestration system and the layer-by-layer absorptances. These properties are in turn combined with layer-specific measurements of the inward-flowing fractions of absorbed solar energy to produce the overall solar heat gain coefficient.

A preceding paper outlined the method and provided the physical derivation of the calculation. In this second of a series of related papers the detailed development of the matrix layer calculation is presented.

1 aKlems, Joseph, H. uhttps://facades.lbl.gov/publications/new-method-predicting-solar-heat-101559nas a2200097 4500008004100000245006100041210006000102520119800162100002201360856007901382 1992 eng d00aNet Energy Performance Measurements on Two Low-E Windows0 aNet Energy Performance Measurements on Two LowE Windows3 a

Experimental studies using the Mobile Window Thermal Test (MoWiTT) Facility were undertaken to compare the performance of low-E windows manufactured with two different technologies, sputter-coated (soft-coat) and an improved pyrolytic chemical vapor deposition (hard-coat). The two technologies produce coatings with different emissivities and solar absorptions. The tests showed that from the standpoint of winter average daily performance, the higher solar transmission of the pyrolytic coatings tends to offset their higher emissivity, making the average performance of windows with the two coatings more similar than one would predict on the basis of either property alone. The tradeoff between the two window types is both orientation and climate dependent. Differences between the two windows were within the small experimental uncertainty of the measurement for all orientations except south, where the pyrolytic coating produced a larger net heat gain. Summer tests in a west-facing orientation showed that both windows produced large solar heat gains if unshaded, and that shading with an interior white venetian blind was not a very effective way of reducing these heat gains.

1 aKlems, Joseph, H. uhttps://facades.lbl.gov/publications/net-energy-performance-measurements-001745nas a2200133 4500008004100000050001400041245008400055210006900139260003400208520124400242100002201486700002401508856007901532 1992 eng d aLBL-3219800aA New Method for Predicting the Solar Heat Gain of Complex Fenestration Systems0 aNew Method for Predicting the Solar Heat Gain of Complex Fenestr aClearwater Beach, FLc12/19923 a

A new method of predicting the solar heat gain through complex fenestration systems involving nonspecular layers such as shades or blinds has been examined in a project jointly sponsored by ASHRAE and DOE. In this method, a scanning radiometer is used to measure the bi-directional radiative transmittance and reflectance of each layer of a fenestration system. The properties of systems containing these layers are then built up computationally from the measured layer properties using a transmission/multiple-reflection calculation. The calculation produces the total directional-hemispherical transmittance of the fenestration system and the layer-by-layer absorptances. These properties are in turn combined with layer-specific measurements of the inward-flowing fractions of absorbed solar energy to produce the overall solar heat gain coefficient.

The method has been applied to one of the most optically complex systems in common use, a venetian blind in combination with multiple glazings. A comparison between the scanner-based calculation method and direct system calorimetric measurements made on the LBL MoWiTT facility showed good agreement, and is a significant validation of the method accuracy and feasibility.

1 aKlems, Joseph, H.1 aWarner, Jeffrey, L. uhttps://facades.lbl.gov/publications/new-method-predicting-solar-heat-gain