Objective - To achieve reductions in building heating and cooling loads and industrial energy use by decreasing measurement uncertainties of the thermal resistance of insulating materials through the assessment of high-temperature insulating materials measurement capabilities (i.e., laboratory comparisons) and investigation of measurement techniques for novel insulating materials.
What is the new technical idea? One of the most cost effective ways of reducing building energy consumption and associated greenhouse gas emissions is thermal insulation. Insulation in the building envelope, thermal appliances, and process industries greatly reduces the demand for space conditioning, hot water, and other thermally active processes. Accurate determination of the insulating capability of these materials is critical to achieve the expected energy savings. In order to facilitate international trade beneficial to U.S. industry, a vital aspect in the development of a measurement program for thermal insulation is the verification of standardized test methods with other national metrology institutes (NMIs) at different temperatures and pressures. Equally important is the subsequent development of reliable thermal conductivity data sets at different temperatures and pressures for the public. NIST will address this problem by 1) participating in international laboratory comparisons with other NMIs; and 2) developing data sets that provide accurate thermal transmission values at elevated temperatures for use by testing laboratories in calibrating test equipment. Another key challenge is determining the insulating capabilities of innovative insulating materials. Novel insulating materials have been proposed to reduce heating and cooling loads in buildings, but the measurement science challenges have not been fully solved. Some materials with potential for greatly reducing energy consumption in buildings include phase change materials, vacuum insulation panels, and micro-porous materials such as aerogels. NIST will initiate an effort to assess the possibilities for such materials to reduce energy consumption in buildings and to address the gaps in the measurement science needed to effectively implement these materials.
What is the research plan? The research plan for FY16 covers three related areas: 1) international comparisons with guarded-hot-plate laboratories at other NMIs; 2) development of NIST thermal insulation data sets at extended temperatures; and 3) establishment of Measurement Services for the NIST 1016 mm guarded-hot-plate apparatus and the NIST 500 mm guarded-hot-plate apparatus. NIST will participate in the following comparisons as part of the method validation for the 500 mm guarded-hot-plate apparatus:
- Bilateral comparison with the National Physical Laboratory which has been delayed while specimens suitable for temperatures to 250 °C could be obtained.
- Multi-lab comparison conducted by the Asia Pacific Metrology Program (APMP.T-S10) under the International Bureau of Weights and Measures (BIPM).
- Invited collaborator in a multi-year European Metrology Research Program for evaluation of the guarded-hot-plate method under high temperatures.
- Bilateral comparison with National Research Council Canada investigation of pressure on the thermal performance of porous solids.
These intercomparisons will help determine best practices in measuring insulation at conditions departing from typical ambient conditions to ensure accurate meaurement results. In conjunction with the laboratory comparisons and the uncertainty analysis conducted in FY15, researchers will prepare the laboratory Quality Manual (QM-III) for the 500 mm guarded-hot-plate measurement services.
In FY16, NIST researchers will verify functional operation of the re-assembled 1016 mm guarded-hot-plate apparatus. Independent measurement systems, such as in-situ thickness, will be validated, as necessary. The resultant thermal performance measurement of the apparatus will be proven initially against internal check standards and, later, by comparison with the NIST 500 mm guarded-hot-plate apparatus. After validation, the 1016 mm guarded-hot-plate apparatus will be used to maintain internal calibrations of the heat-flow-meter apparatus and to continue investigations of advanced insulations, such as microporous insulation and vacuum insulation panels.
- 2010 Buildings Energy Data Book, Table 2.1.6 and 3.1.5, respectively.