02228nas a2200205 4500008004100000245010200041210006900143260003300212490001600245520148700261653003701748653002201785653002501807100002101832700002901853700002201882700002101904700002701925856007001952 2006 eng d00aMonitored Energy Performance of Electrochromic Windows Controlled for Daylight and Visual Comfort0 aMonitored Energy Performance of Electrochromic Windows Controlle aQuebec City, Canadac10/20060 v112 Issue 23 a

A 20-month field study was conducted to measure the energy performance of south-facing large-area tungsten-oxide absorptive electrochromic (EC) windows with a broad switching range in a private office setting. The EC windows were controlled by a variety of means to bring in daylight while minimizing window glare. For some cases, a Venetian blind was coupled with the EC window to block direct sun. Some tests also involved dividing the EC window wall into zones where the upper EC zone was controlled to admit daylight while the lower zone was controlled to prevent glare yet permit view. If visual comfort requirements are addressed by EC control and Venetian blinds, a 2-zone EC window configuration provided average daily lighting energy savings of 10-15% compared to the reference case with fully lowered Venetian blinds. Cooling load reductions were 0-3%. If the reference case assumes no daylighting controls, lighting energy savings would be 44-11%. Peak demand reductions due to window cooling load, given a critical demand-response mode, were 19-26% maximum on clear sunny days. Peak demand reductions in lighting energy use were 0% or 72-100% compared to a reference case with and without daylighting controls, respectively. Lighting energy use was found to be very sensitive to how glare and sun is controlled. Additional research should be conducted to fine-tune EC control for visual comfort based on solar conditions so as to increase lighting energy savings.

10abuilding automation and controls10aBuilding envelope10acommercial buildings1 aLee, Eleanor, S.1 aDiBartolomeo, Dennis, L.1 aKlems, Joseph, H.1 aYazdanian, Mehry1 aSelkowitz, Stephen, E. uhttps://facades.lbl.gov/publications/monitored-energy-performance01168nas a2200133 4500008004100000050001500041245004900056210004900105260002900154490001600183520073800199100002200937856007500959 2002 eng d aLBNL-5145300aMeasured Winter Performance of Storm Windows0 aMeasured Winter Performance of Storm Windows aKansas City, MOc07/20030 v109, Part 23 a

Direct comparison measurements were made between various prime/storm window combinations and a well-weatherstripped, single-hung replacement window with a low-E selective glazing. Measurements were made using an accurate outdoor calorimetric facility with the windows facing north. The double-hung prime window was made intentionally leaky. Nevertheless, heat flows due to air infiltration were found to be small, and performance of the prime/storm combinations was approximately what would be expected from calculations that neglect air infiltration. Prime/low-E storm window combinations performed very similarly to the replacement window. Interestingly, solar heat gain was not negligible, even in north-facing orientation.

1 aKlems, Joseph, H. uhttps://facades.lbl.gov/publications/measured-winter-performance-storm00835nas a2200145 4500008004100000050001400041245004700055210004700102260003400149520037100183100002200554700002100576700002000597856007200617 1995 eng d aLBL-3774700aMeasured Performance of Selective Glazings0 aMeasured Performance of Selective Glazings aClearwater Beach, FLc12/19953 a

Measurements of the net heat flow through four selective glazings in comparison with clear double glazing under late summer outdoor conditions are presented. The solar heat gain coefficient (SHGC) for each glazing is extracted from the data and shown to be angle-dependent. Good agreement is found between measured properties and calculations with WINDOW 4.1.

1 aKlems, Joseph, H.1 aYazdanian, Mehry1 aKelley, Guy, O. uhttps://facades.lbl.gov/publications/measured-performance-selective01775nas a2200133 4500008004100000050001400041245007900055210006900134490001600203520130100219100002201520700002401542856007501566 1995 eng d aLBL-3624300aMeasurement of Bidirectional Optical Properties of Complex Shading Devices0 aMeasurement of Bidirectional Optical Properties of Complex Shadi0 v101, 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.

This paper describes the method of measuring the spatially averaged bidirectional optical properties using an automated, large-sample gonio-radiometer/photometer, termed a Scanning Radiometer. Property measurements are presented for one of the most optically complex systems in common use, a venetian blind. These measurements will form the basis for optical system calculations used to test the method of determining performance.

1 aKlems, Joseph, H.1 aWarner, Jeffrey, L. uhttps://facades.lbl.gov/publications/measurement-bidirectional-optical01301nas a2200133 4500008004100000050001400041245009400055210006900149490001600218520081200234100002101046700002201067856007801089 1993 eng d aLBL-3471700aMeasurement of the Exterior Convective Film Coefficient for Windows in Low-Rise Buildings0 aMeasurement of the Exterior Convective Film Coefficient for Wind0 v100, Part 13 a

The MoWiTT field facility is used to measure the convective film coefficient over the exterior surface of a window. The MoWiTT-measured data is compared to some commonly-used experimental and theoretical models. The comparison shows that the MoWiTT data disagrees with the previously used models such as the ASHRAE/DOE-2 model. The reasons for these disagreements are discussed. An experimental model, based on the MoWiTT data, is presented to correlate the film coefficient with the difference in temperatures of the exterior glass surface and the ambient, in the natural convection region, and with the site wind speed, in the forced convection region. The wind speed is considered both in windward and leeward hemispheres. The validity of the MoWiTT model for low-rise buildings is then discussed.

1 aYazdanian, Mehry1 aKlems, Joseph, H. uhttps://facades.lbl.gov/publications/measurement-exterior-convective-film