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Anaerobic Sludge Digestion
Published in Jr. Malina, F. Joseph, Frederick G. Pohland, Design of Anaerobic Processes for the Treatment of Industrial and Municipal Wastes, 2017
Jr. Malina, F. Joseph, Frederick G. Pohland
The heat losses can be reduced by insulating the digestion tank cover and walls exposed to the ambient air. Common insulating materials used include a dead air space, lightweight insulating concrete, glass wool, insulation board, and urethane foam. The insulation material frequently is covered to protect the insulation and for aesthetic purposes. Common facing materials include brick, metal siding, precast concrete panels, and stucco.
Exterior Enclosure Components
Published in Kathleen Hess-Kosa, Building Materials, 2017
Siding is a term of many meanings! It is, in the strictest sense, exterior wall cladding. Yet, to the layperson, sales persons, many builders, and herein, siding refers to long, thin panels—the most commonly recognized of which is “vinyl siding.” Other siding building materials include, but are not limited to, wood, metal, fiber cement, and fiberboard. Each comes in rectangular panels as well, providing easier, quicker coverage, and panels may be formed into different formats (e.g., faux stacked stone vinyl panels). Siding/panel materials discussed here include (1) metal; (2) wood; (3) fiber cement; (4) hardboard; and (5) vinyl.
Thermal resistance of ventilated air-spaces behind external claddings; definitions and challenges (ASHRAE 1759-RP)
Published in Science and Technology for the Built Environment, 2021
Mohammad Rahiminejad, Dolaana Khovalyg
Verification and validation are important components of any model development. To validate the analytical solution, computed temperatures of surfaces were compared with the results of two hot-box tests referenced in the work statement of 1759-RP (Meyer et al. 2019; EXOVA Test Report 2011). The testing by Meyer et al. (2019) considered brick cladding with a 0.07 m/s forced ventilation airflow behind the brick veneer. EXOVA tested vinyl siding with a conventional hot-box test using a mixing fan airflow applied to an exterior side of the assembly. In contrast to the test performed by Meyer et al. (2019), no forced ventilation air-flow behind the siding was applied. Thus, the airflow behind the vinyl siding only occurs as a result of mixing fan-induced airflow over the surface of the vinyl siding.
Measuring the effective thermal resistance of ventilated air-spaces behind common wall assemblies: Theoretical uncertainty analysis and recommendations for the hot box method modifications (ASHRAE 1759-RP)
Published in Science and Technology for the Built Environment, 2022
Mohammad Rahiminejad, Dolaana Khovalyg
The relative uncertainty of the total thermal resistance is formulated in Appendix B, and the values determined are tabulated in Table 2. The temperature difference between indoor and outdoor spaces remains constant in summer and winter conditions. Therefore, the relative uncertainty of the total thermal resistance of the air gap does not considerably change for brick and vinyl siding. A comparison is made with the relevant studies in the literature to evaluate the results obtained for the uncertainty of the total R-value. Based on the results provided in the ASTM 1363-05 test report (2009), the uncertainty of the testing series performed on a ventilated brick wall is ranged from 1.84% to 2.08%. The uncertainty of measurements of R-value for a wall system with a ventilated cavity behind vinyl siding is reported as 1.65% (EXOVA Test Report 2011). The maximum uncertainty associated with the total R-value measurements of wall structures using Guarded Hot Box method is reported be equal to 6.5% (Elmahdy 1992; Elmahdy et al. 2010). Considering the range of uncertainties for calculated in this study, it can be seen that the values are within the same range as reported in similar wall assemblies. Only when high precision sensors are assumed (i.e., ±0.18(0.10 °C) for temperature and 3% for heat flux sensor), the uncertainty becomes lower, which is the best-case scenario theoretically explored. According to the results, the relative uncertainty of the total R-value is much smaller than the corresponding values for the effective thermal resistance of the air-space; this is mainly due to the higher resulting values of The results also reveal that the difference between the relative uncertainty of the total R-value in brick and vinyl siding claddings is negligible. Despite the change in the heat flux passing through the wall core, the relative uncertainty does not change remarkably since the temperature difference is the same in both cases because outdoor and indoor temperatures are fixed.