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Typical Pre-Commissioining and Start-Up Procedures
Published in Maija Virta, HVAC Commissioning Guidebook, 2021
After filling, flushing and venting a system, the pressure test needs to be carried out based on the following principles: Water piping shall be hydrostatically tested to a pressure to 1–1.5 times design pressure;Test shall be performed for at least 24 hours with fluctuation in pressure;Pressure testing shall be performed prior to installation of thermal insulation. All joints must be fully exposed to environment;Underground and other piping that will be subsequently get covered after construction shall not be covered without prior approval of successful testing. Pipe insulation can be done only after pressure testing of system. Chilled water pipes operate at below-ambient temperatures and therefore the water vapour condenses on the pipe surface. Moisture creates many different types of problems like corrosion, so preventing the formation of condensation on pipework is usually considered important. Pipe insulation is also important to reduce the energy loss in the pipework.
Insulation Systems
Published in Stephen A. Roosa, Steve Doty, Wayne C. Turner, Energy Management Handbook, 2020
Javier A. Mont, Michael R. Harrison
Piping for both hot and cold service is normally insulated with fiberglass pipe insulation. For cold work, the vapor-barrier jacket is sealed at the overlap with either an adhesive or a factory-applied self-seal lap. If staples are used, they should be dabbed with mastic to secure the vapor resistance. Aluminum jacketing is often used on exterior applications, with a vapor barrier applied beneath if it is for cold service. Domestic hot- and cold-water plumbing and rain leaders commonly are insulated with fiberglass. Insulation around piping supports takes many forms, depending on the nature of the hangers or supports. On cold work, using a clevis hanger on the outside of the insulation requires a high-density insert to support the weight of the piping. This eliminates the problem of adequately sealing the vapor barrier penetrations.
High-Fidelity Modeling and Experiments to Inform Safety Analysis Codes for Heat Pipe Microreactors
Published in Nuclear Technology, 2023
Carolina da Silva Bourdot Dutra, Elia Merzari, John Acierno, Adam Kraus, Annalisa Manera, Victor Petrov, Taehwan Ahn, Pei-Hsun Huang, Dillon Shaver
Figure 2 shows a schematic diagram of the test facility. The test section assembly consists of the evaporator (254 mm), adiabatic (508 mm), and condenser (254 mm) sections. For the evaporator section, the double spiral–shaped silicon-carbide (SiC) heater (52-mm OD, 40-mm inner diameter, and 254-mm heating length) was used to heat the heat pipe through radiational heat transfer with a maximum operable temperature of 1200°C. The material for the heater was selected with a consideration for a low-Z number to reduce the attenuation of X-rays for the radiography measurement. The heater was fixed to a support, as shown in Fig. 2, and calcium-silicate parts were used for the concentric alignment, protection of the brittle heater, and electrical insulation. The heater was covered with mineral wool pipe insulation with a 220-mm OD .
Determining economic and environmental impact of insulation by thermoeconomic and life cycle assessment analysis for different climate regions of Turkey
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2021
There are numerous studies in the open literature about optimum insulation thickness based on economic analysis. In these studies, the optimum insulation thickness (OIT) was calculated using the Life Cycle Cost (LCC) method. In calculations carried out with this method, heating degree day (HDD) and cooling degree day (CDD) values, which are the parameters affecting the optimum insulation thickness, were used. In literature, studies on optimum insulation thickness have been generally investigated for pipes and exterior surfaces of buildings. OIT calculations were performed on pipes with different thermal insulation materials and diameters. Pipes with larger diameters have been found to save more energy. In addition, the two most important parameters that determine OIT are lifetime and unit cost of insulation material (Ertürk 2016). In the analysis performed by economic and environmental cost, the OIT calculated with the environmental approach is higher. (Açıkkalp and Yerel Kandemir 2018). In OIT calculations for pipes of different sizes, the effect of the air gap was examined. It is concluded that the air gap in small diameter pipes is effective in energy saving. It was found that the insulation thickness plays an important role in energy saving for large diameter pipes (Daşdemir et al. 2017a). Economic and exergy approach was combined in pipe insulation to determine the effect of thermal insulation. The OIT value determined by the exergoeconomic method was found to be higher. (Yin et al. 2018). Economic analyses were carried out for various fuel and insulation materials in pipes for different material types. It is concluded that the most effective fuel in terms of energy-saving is fuel oil and insulation material is rockwool (Daşdemir et al. 2017b).