Evaluation of Solar Heat Gain Coefficient and Transmittance, Reflectance & Emittance Measurement of Flat Glass by UV-Visible/NIR Spectroscopy

By Satoko Suzuki

Introduction

Heat shield glass is typically made from eco-friendly materials that help in the prevention of global warming and reduction in energy costs. Testing methods for the evaluation of heat shield glass is stipulated by JIS R3016 and require visible transmittance, visible reflectance, solar transmittance, solar reflectance, and emittance measurements. From these measurements, the solar heat gain coefficient can be calculated, which is defined as the fraction of incident solar radiation admitted through a window.

This application note shows how to obtain and evaluate transmittance/reflectance spectra of a flat glasses using an integrating sphere and calculate the solar radiation absorbance using the Solar Transmittance/Reflectance Visible Light Transmittance/Reflectance program.

Experimental

Measurement Conditions
Measurement Range	2500-300nm	Data Pitch	0.5 nm
UV/Vis Bandwidth	5.0 nm	NIR Bandwidth	25.0 nm
Scan Speed	400 nm/min	Response	Fast

Keywords

190-RF-0217, V-670, UV-Visible/NIR, ISN-723 Integrating sphere, VWST-774 Solar Transmittance/Reflectance Visible Light Transmittance/Reflectance program, solar heat gain

Results

Spectra of both heat shield glass and conventional glass were measured and are shown in Figure 1.

Figure 1. Transmittance (left) and reflectance (right) spectra of heat shield glass (green) and conventional glass (blue).

The solar radiation results of the heat shield and conventional glass were calculated using the Solar Transmittance/Reflectance Visible Light Transmittance/Reflectance program and are shown in Figure 2 and Table 1.

Figure 2. Solar Transmittance/Reflectance Visible Light Transmittance/Reflectance program.

	Heat Shield Glass %	Conventional Glass %
Solar Radiation Transmittance	41.89	86.10
Solar Radiation Reflectance	31.85	7.82
Solar Radiation Absorbance	26.26	6.08
Visible Light Transmittance	76.38	89.95
Visible Light Reflectance	8.80	8.52

This document has been prepared based on information available at the time of publication and is subject to revision without notice. Although the contents are checked with the utmost care, we do not guarantee their accuracy or completeness. JASCO Corporation assumes no responsibility or liability for any loss or damage incurred as a result of the use of any information contained in this document. Copyright and other intellectual property rights in this document remain the property of JASCO Corporation. Please do not attempt to copy, modify, redistribute, or sell etc. in whole or in part without prior written permission.

About the Author

Satoko Suzuki is a senior manager of the molecular spectroscopy applications laboratory at the JASCO facility in Hachioji Japan.

Introduction

Experimental

Measurement Conditions
Measurement Range	2500-300nm	Data Pitch	0.5 nm
UV/Vis Bandwidth	5.0 nm	NIR Bandwidth	25.0 nm
Scan Speed	400 nm/min	Response	Fast

Results

Spectra of both heat shield glass and conventional glass were measured and are shown in Figure 1.

	Heat Shield Glass %	Conventional Glass %
Solar Radiation Transmittance	41.89	86.10
Solar Radiation Reflectance	31.85	7.82
Solar Radiation Absorbance	26.26	6.08
Visible Light Transmittance	76.38	89.95
Visible Light Reflectance	8.80	8.52

Keywords

190-RF-0217, V-670, UV-Visible/NIR, ISN-723 Integrating sphere, VWST-774 Solar Transmittance/Reflectance Visible Light Transmittance/Reflectance program, solar heat gain

Introduction

Experimental

Keywords

Results

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V-770 UV-Visible/NIR Spectrophotometer

V-780 UV-Visible/NIR Spectrophotometer

About the Author