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Polymers utilised in construction
Published in Ash Ahmed, John Sturges, Materials Science in Construction: An Introduction, 2014
Commonly abbreviated to PEX or XLPE, this is a form of polyethylene with cross-links. It is formed into tubing and is used predominantly in radiant heating systems, domestic water piping and insulation for high-tension electrical cables. Recently, it has become a viable alternative to polyvinyl chloride (PVC), chlorinated polyvinyl chloride (CPVC) or copper pipe for use as residential water pipes. The advantageous properties of PEX also make it a candidate for progressive replacement of metal and thermoplastic pipes, especially in long-life applications, because the expected lifetime of PEX pipes reaches 50–200 years. PEX has become a contender for use in residential water plumbing because of its flexibility. It can be turned through 90 degrees either by a wide turn or using an adapter; PVC, CPVC and copper all require elbow joints. It also has the capacity to run tubing directly from a distribution point continuously to the desired outlet fixture without cutting or splicing; this reduces the need for potentially weak and costly joints. The cost of material can also be approximately 20 per cent less than alternatives, and installation is much less labour intensive. Almost all PEX is made from high-density polyethylene (HDPE). PEX contains cross-link bonds that change the material from a thermoplastic into an elastomer. The cross-linking imparts excellent properties: first, the high-temperature properties of the polymer are improved with the strength maintained to 120–150 °C; second, its impact and tensile strength, scratch resistance and resistance to brittle fracture are enhanced.
Basic Materials Engineering
Published in David A. Hansen, Robert B. Puyear, Materials Selection for Hydrocarbon and Chemical Plants, 2017
David A. Hansen, Robert B. Puyear
Chlorinated Polyvinyl Chloride (CPVC). CPVC’s chemical resistance is similar to, but usually better than, that of PVC. Its primary advantage over PVC is a higher use temperature, nearly 212°F (100°C). Its primary use is for hot water piping and for inorganic aqueous solutions. Because of its high chlorine content, it has considerable flame resistance.
Experimental study in a compound parabolic solar concentrator with different configurations of thermal energy storage system
Published in International Journal of Green Energy, 2023
Sathiya Satchi Christopher, Kalilur Rahiman Arshad Ahmed, Ashokkumar Shyam, Selvarasan Iniyan
In this experimental study, the performance of CPC solar collector with different configurations of the TES system (sensible, single PCM, two PCMs, three PCMs, and six PCMs) was investigated. The schematic of the proposed CPC-type solar collector integrated with the TES system is shown in Figure 1. The system has an aperture area of 2.52 m2, with the TES makeup water tank capacity of 200 L, a 9 kW electric heater, pump, and other necessary components. Each component is connected by chlorinated polyvinyl chloride (CPVC) pipes, wrapped in glass wool for insulation and the entire test rig anchored to the ground to avoid vibrations. The schematic arrangement of the system with electric heater given in necessary openings is provided to accommodate the resistance temperature detectors (RTDs) at various locations of the TES system and the solar collector. Table 1 shows the details of the geometrical parameters and materials of the CPC solar collector.
Measuring convection heat transfer coefficients and thermal resistance for protective fabrics using a heated cylinder in a wind tunnel
Published in The Journal of The Textile Institute, 2022
Tamsaki Asawo, David Torvi, David Sumner
The cylinder was mounted vertically in the wind tunnel test section as shown in Figures 1 and 2, and had an overall height of H = 881 mm and a diameter of D = 48 mm with three major sections. The heated middle section of the cylinder was located at equal distance from the roof of the test section and the ground plane (Figure 1). This heated section was sufficiently far from the roof and ground plane, plus the cylinder’s overall aspect ratio of AR=H/D = 18 was sufficiently high, such that the airflow around the heated middle section of the cylinder could be considered two-dimensional (2D). This heated section had a height of H2D=288 mm and was made of solid brass, which has a relatively high thermal conductivity, to reduce the temperature gradient through the cylinder. Two other cylindrical sections with the same diameter, fabricated using chlorinated polyvinyl chloride (CPVC) plastic pipes, were added above and below the heated section and extended to the ground plane and the roof of the test section (Figures 1 and 2).
Algal biomass harvesting using low-grade waste heat: the effect of waste heat temperature and air speed on dewatering algal suspension
Published in Biofuels, 2022
Ramin E. Yazdi, Temesgen Garoma
The heat exchanger was a shell and tube type with a nominal capacity of 20 kW and heat transfer area of 2.79 ft2 (AIC Alliance, model B 70). The heat exchanger was insulated with Frost King 1-inch fiberglass plumbing pipe wrap insulation (model SP42x) and with a 10-mm sponge foam sheet to minimize heat loss through convection. The evaporation tank is made of 2″ and ¾″ Chlorinated Polyvinyl Chloride pipe and Lasco CPVC-sch80 fittings that tolerate temperatures up to 99 °C. The temperature of the gas at the heat exchanger inlet was measured with an RTD Platinum Thermometer (VWR, model 23609-228) with 0.2 °C accuracy for temperature values of 200 °C or below. The temperatures of the algal suspension and air stream in the evaporation tank and reservoir were measured in different locations using Fisherbrand™ Traceable™ Full-Scale thermometers (Fisher Scientific, model 15-077-940) with ±1 °C temperature accuracy. The low-grade heat for the research was modeled using two heat guns in parallel (Porter Cable, model PC1500HG-19CMF) with a total mass flow rate of about 4.40 g/s. The heat guns were used in parallel to increase the air flow.