Copper Pipe Research Articles

Cultivation of Organics in Controlled Environment Greenhouse

A greenhouse is essentially an enclosed structure, which traps the short wavelength solar radiation and stores the long wavelength thermal radiation to create a favourable microclimate for higher productivity. The sun’s radiation incident on the greenhouse has two parts: direct radiation and an associated diffuse sky radiation. The diffuse part is not focused by the lenses and goes right through Frensel lenses onto the surface of the absorbers. This energy is absorbed and transformed into heat, which is then transported via the liquid medium in copper pipes to the water (heat) storage tanks or, if used, open fish tanks. In this way, an optimal temperature for both plant cultivation and fish production can be maintained. Stable plant growth conditions are light, temperature and air humidity. Light for the photosynthesis of plants comes from the diffuse radiation, which is without substantial fluctuations and variation throughout most of the day. The air temperature inside the greenhouse is one of the factors that have an influence on the precocity of production. The selective collector acts in a more perceptible way on extreme air temperatures inside the greenhouse. Hence, the system makes it possible to avoid the excessive deviation of the temperature inside the greenhouse and provides a favourable microclimate for the precocity of the culture. Sediment and some associated water from the sediment traps are used as organic fertiliser for the plant cultivation. The present trend in greenhouse cultivation is to extend the crop production season in order to maximise use of the equipment and increase annual productivity and profitability. However, in many Mediterranean greenhouses, such practices are limited because the improper cooling methods (mainly natural or forced ventilation) used do not provide the desired micro-climatic condition during the summer of a composite climate. Also, some of these greenhouses have been built where the meteorological conditions require some heating during the winter, particularly at night. The worst scenario is during the winter months when relatively large difference in temperature between day and night occurs. However, overheating of the greenhouse during the day is common, even in winter, requiring ventilation of the structure. Hence, several techniques have been proposed for the storage of the solar energy received by the greenhouse during the day and its use to heat the structure at night. Reviews of such techniques are presented in this article. Air or water can be used for heat transport. The circulating water is heated during the day via two processes. The water absorbs part of the infrared radiation of the solar spectrum. Since the water is transparent in the visible region, they do not compete with the plants that need it. Alternatively, the water exchanges heat with the greenhouse air through the walls. At night, if the greenhouse temperature goes down below a specified value, the water begins to circulate acting as heat transfer surfaces heating the air in the greenhouse.

In memoriam: John R. Mallard (1927-2021).

In memoriam: John R. Mallard (1927-2021).

Experimental study on heat transfer characteristics of closed thermosyphon at different volumes and inclination angles for variable vacuum pressures

In this study, the thermal performance of vacuumed copper pipe has been experimentally investigated by using different volume values of 5 ml, 10 ml, 15 ml, and 20 ml with inclination angles of 45°, 60°, and 90° for variable vacuum pressures. For this purpose, the inner, outer diameter, and length of the vacuumed pipes filled with the distilled water were 26 mm, 28 mm, and 1500 mm, respectively. This copper pipe was vacuumed until the absolute pressure of 6.32 kPa and immersed in a heat source at a constant temperature of 82°C at the beginning of the experiments. The surface temperatures of the vacuumed pipes were measured at twenty different points by using K-type thermocouples in two different data loggers. All calculations were performed as variable saturation temperatures at variable vacuum pressures with changing the time. According to the results, the experimental boiling heat transfer coefficients showed a good agreement with the correlations in the literature. Also, the best thermal resistance was obtained in the vacuumed copper pipe with a water volume of 10 ml at the inclination angle of 90° until the end of the experiment.

Design of Miniature Clamp-On Ultrasonic Flow Measurement Transducers

Clamp-on ultrasonic transit-time difference measurements of liquid flowrate are widely used in industry for both flow metering and heat metering applications. However, the sensors used tend to be relatively large, hindering their use on small diameter pipes, and using more material in the transducer wedge than is strictly necessary. The accuracy of the technique depends on a number of factors, and particularly on the accuracy of the compression wave speed in the liquid that is used in the calculations to obtain flowrate or heat transfer rate from the liquid in the pipe. Many flow meters either assume a value for the wave speed or obtain it using thermocouple measurements of the pipe exterior with a lookup table or simple equation. An error in the liquid ultrasonic velocity relates directly to errors in the calculated flowrate. It is highly beneficial if the ultrasonic wave speed in the liquid can be accurately measured in real time for flowrate calculations, especially for temperature and pressure varying conditions. A new type of small clamp-on ultrasonic transducer is reported, using a 6-mm-wide PEEK wedge that contains two piezoelectric elements, one of which generates sound normal to the flow direction, yielding the measurement of ultrasonic wave speed in the liquid. The new transducers were tested on a small rig with a 15-mm diameter copper pipe and a 70-mm diameter stainless steel pipe, yielding accurate measurements of liquid ultrasonic velocity and flowrates.

Degradation of carbamazepine and disinfection byproducts formation in water distribution system in the presence of copper corrosion products

Copper ion (Cu2+), a common corrosion product released from copper pipes, is widely present in water distribution system (WDS). Cu2+ was confirmed to be capable to catalyze the decay of monochloramine (NH2Cl), which is a commonly used disinfectant and need to maintain a minimum concentration in WDS. Cu2+ and NH2Cl form a system in WDS and their interaction with other substances in WDS is unclear. In this study, the performance of Cu2+/NH2Cl system on degradation of trace pollutants, taking carbamazepine (CBZ) as an example, in WDS was investigated, and significant promotion on CBZ degradation was observed. The acceleration was due to the generation of Cl, OH and other oxidants, which were identified by scavenge experiments. CBZ degradation in Cu2+/NH2Cl system was highly pH-dependent, because the catalytic effect of Cu2+ can only work at low pH (Cu2+ precipitating at pH > 6.0). The removal of CBZ increased with the concentration of Cu2+ increasing. Water matrix (NOM, HCO3− and Br−) can inhibit the removal of CBZ in Cu2+/NH2Cl system. Further, five disinfection byproducts (DBPs), namely, trichloromethane (TCM), dichloroacetonitrile (DCAN), dichloroacetone (DCP), trichloronitromethane (TCNM) and trichloroacetone (TCP), were detected in chloramination in the presence/absence of Cu2+. Compared with chloramination without Cu2+, the cytotoxicity and genotoxicity of formed DBPs increased significantly in the presence of Cu2+, indicating that the chemical safety in WDS deserves more attention.

Enhancing the performance of heat pumps by immersing the external unit in underground water storage tanks

Renewable energy sources have a considerable potential to contribute to sustainable development and have the potential to reduce the reliance on fossil fuels. Direct-Expansion Water Source Heat Pump (DX-WSHP) could be used in air conditioning applications as an energy-efficient environmental-friendly system. In this study, DX-WSHP potential for air conditioning of a multi-level residential building was numerically examined. A closed-loop of copper pipes filled with R134a, as a refrigerant, was immersed in an underground water tank that is used as a heat sink/source. Cooling/Heating loads of the residential unit under three different climate conditions were estimated at different floor levels. The proposed system takes advantage of a higher heat transfer rate in water and better thermal performance when compared with traditional Air Source Heat Pumps (ASHP). A mathematical model was built to examine the performance of the system using the Engineering Equations Solver (EES) software. Results have shown that the DX-WSHP has outperformed the ASHP at a lower (higher) condensing (evaporating) temperature in the cooling (heating) mode with higher values of COP varies from 30% to 118%. Furthermore, there was a significant reduction in economic and environmental impacts, CO2 emissions, and electrical energy consumption of the DX-WSHP system for the three different climate conditions. The reduction in CO2 emissions varied from 8% to 40%. Additional advantages of the proposed system were found: energy-saving and overcoming the problems concerning heat rejection to the surrounding air and the outdoor fan noise.

Effect of Benzotriazole on the Localized Corrosion of Copper Covered with Carbonaceous Residue.

Carbonaceous residues on copper pipes during the manufacturing process are known to be one of the main causes of pitting corrosion on copper pipes. This study examined the corrosion-inhibiting effect of benzotriazole (BTA) on C12200 copper pipes with carbonaceous film in synthetic tap water. In the absence of BTA, localized corrosion mechanisms due to galvanic corrosion, crevice corrosion, and oxygen-concentration cell were proposed in the boundary part of the carbonaceous film on the copper through X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) with energy dispersive spectrometer (EDS) analyses. Electrochemical tests showed that BTA inhibits corrosion by forming Cu−BTA complexes on all over the copper surface where carbonaceous film is present. BTA mitigates galvanic corrosion and crevice corrosion at the boundary of the carbonaceous film and suppresses the formation of oxygen-concentration cells through the formation of a Cu−BTA complex.

Comparison of individual and sequential copper piping systems in an experimental artificial ground freezing model

Comparison of individual and sequential copper piping systems in an experimental artificial ground freezing model

Thermal performance of geothermal pavements constructed with demolition wastes

This paper investigates the potential of harvesting heat energy from geothermal pavements constructed with construction and demolition (C&D) waste materials, by using experimental and numerical methods. The deformation, stiffness, and shear strength properties of two types of C&D materials used for the construction of geothermal pavements, namely crushed brick (CB) and recycled concrete aggregate (RCA), were evaluated by performing repeated load triaxial (RLT) and quick shear tests. A multistage RLT test was adopted to investigate the deformation behavior of CB and RCA over a wide range of stress levels. The stiffness of materials was evaluated in different stress combinations. A small-scale prototype pavement system with a serpentine-shaped copper pipe was placed in the C&D base layer for evaluating the potential of heat energy extraction. Comparisons were made between the performance of CB and RCA for construction of geothermal pavements. RCA was found to be considerably superior to CB in terms of strength and deformation properties. On the other hand, the geothermal pavement constructed with CB was found to have slightly more favorable thermal performance due to the higher thermal conductivity of CB compared to RCA. A numerical model was developed and validated based on the experimental results to investigate the effect of design parameters on the thermal performance of the geothermal pavements. The effect of base layer thermal conductivity, Reynolds number, solar irradiance, inlet water temperature, and pipe embedment depth, was investigated on the surface temperature reduction and heat gain of the system. Overall, the construction of geothermal pavement with C&D materials was found to be a feasible approach which further enhances the environmental sustainability of the system.

Corrosion protection of copper pipes in cooling systems using poly styrene solution in North oil Company/Baba Gorge

This research includes a study of the problem of corrosion in petroleum industry which decaying inthe body of the Iraqi economy, and it is Non-controlled accurately and resorting to toggle mechanismand import of machinery and equipment, which cost the country large sums of money.Four Solutions of gasoline distillates and toluene was prepared and attended the five types ofsolvents, by taking 100 ml of each distilled and dissolved (30) grams of material polystyrene (cork),(available, cheap and that its presence is causing pollution to the environment), then used 5 ml of aproduce mixture in a different rates mixing of distillates and toluene. Solutions have been tested onfifteen models of copper pipes for cooling devices are processed for the study after welded andpainted and placed at the area Baba gurgur region in the North Oil Company-Iraq as an affected areagases that cause corrosion of copper pipes in the cooling devices, the mixture of number (4) has beenshown a very good resistance for corrosion after nine months from the time of exposure to the gas.

Communication—A Rotating Ring Disk Study to Monitor the Concentration of 2M5S in Copper Low TEC Electrolytes

A leveller additive, 2-mercapto-5-benzimidazolesulfonic acid (2M5S), is characterized and monitored by cyclic voltammetry stripping (CVS) measurements using a rotating ring disk electrode (RRDE). The ring current gradually decreases with the increase of 2M5S concentration from 1 to 8 ppm. The relationship between the ring current and 2M5S concentration is used for determining the deterioration of the low thermal expansion coefficient (TEC) copper electrodeposition solution. The amount of 2M5S in the 20-hour-electrolyzed solution has been monitored then supplied. The copper pipe electrodeposited with the refreshed solution achieved low TEC, approximately the same as the copper pipe electrodeposited with the fresh solution.

Reduced Copper Piping Corrosion in Sprinkler Facilities

Copper pipes used in fire sprinkler systems are somewhat superior to steel pipes in terms of corrosion resistance. They have been widely used in apartments since 2010, but their firefighting performance has not been firmly established due to leakage caused by pitting. In order to solve this problem, copper pipes need to be replaced by pipes made of other materials such as STS or C-PVC, which, however, would impose an economic burden on the party responsible for maintenance, as well as economic loss to other relevant parties and inconvenience to residents. Although 27 leakages occurred in the E region in 2018, it was found that the number of incidents was reduced to just one case after an application of corrosion inhibitor. Therefore, for 2 months beginning in October 2020, a second project to reduce piping corrosion was conducted with 2,000 households in five regions nationwide. During this period, the standing fire water of five apartment buildings in the A region was measured as having a pH 8.34–9.08, an ORP -94.9–-135.8 mV, and an EC 0.097–0.137 ms/cm, which indicated a need for improvement. Subsequently, a corrosion inhibitor was poured into the fire water, resulting in improved values of pH 11.13–11.26, ORP -257–-265.5 mV, and EC 4.189–5.769 ms/cm, which demonstrated the effect of preventing pipe corrosion. It was evident that water-soluble silicate was adsorbed on the metal pipe of the anode to form a thin monolayer, which induced basicity by increasing the pH and by decreasing the ORP, which eventually minimized corrosion.

Enhanced formation of dichloroacetamide and dichloroacetonitrile during chloramination of drinking water and model organic matters in the presence of copper corrosion products

The formation of nitrogenous disinfection byproducts (N-DBPs) occurs in chloraminated water in drinking water distribution systems and may be affected by metal pipe materials and their corrosion products. The effect of copper corrosion products, including Cu2+, CuO, and Cu2O, on the formation of dichloroacetonitrile (DCAN) and dichloroacetamide (DCAcAm) was investigated during chloramination of natural organic matter (NOM), model precursors (carboxylic acids and amino acids), and real water samples. Copper corrosion products enhanced DCAN and DCAcAm formation during chloramination of NOM by 33%–72% and 11%–80%, respectively. Addition of 15N-labeled monochloramine showed that the copper corrosion products primarily enhanced the formation of DCAN using organic nitrogen and monochloramine as nitrogen sources, and the formation of DCAcAm using monochloramine as the nitrogen source, but had a limited impact on the formation of DCAcAm using organic nitrogen as the nitrogen source. A distinct N-DBP formation pathway in the presence of Cu2+ and CuO was observed using tyrosine as a model compound, which included the formation of 1,4-benzoquinone as a dominant intermediate. On reaction with monochloramine, the 1,4-benzoquinone greatly contributed to enhancement of DCAN and DCAcAm formation using monochloramine as the nitrogen source. During chloramination of real water samples, Cu2+ and CuO enhanced DCAN formation by 9–40% and DCAcAm formation by 16–33%. This study increases our knowledge of copper catalyzed DCAN and DCAcAm formation in copper pipes, which will be meaningful for water safety in distribution systems using chloramine disinfection.

The Improvement on the Efficiency of Photovoltaic Module using Water Cooling

This study denotes an effective design for thermal regulating by integrating the water-cooling system on photovoltaic (PV) panel. The efficiency of the PV module will reduce the increasing temperature on the panel. Thus, the focus of this study is to improve the efficiency of the PV module by maintaining a low operating temperature. A modification on the rear part of the PV panel is executed by integrating the water-cooling system by using copper pipe. This study is conducted to compare the effects of the PV panel when it is tested in different circumstances, such as with and without water-cooling system as well as a variation of water flow rates at constant solar irradiance. Comparative analyses are performed by conducting I-V and P-V curve as well as temperature test where both tests take these different conditions into account. The study exhibits that the utilisation of water-cooling system will result to a reduced rear temperature of the PV panel. The efficiency of the PV panel has also experienced an increase of 3% for 300 l/h flow rates compared to the one without water-cooling system. The increase of flow rates of the water-cooling system will reduce the rear temperature of the PV panel. In other words, a more massive reduction of temperature on the PV panel with 16°C is detected when the water-cooling system is utilised up to 300 l/h flow rates in 60 minutes duration at 350 W/m2 solar irradiance.

Filling Ratio Optimization for High-Performance Nanoengineered Copper-Water Heat Pipes

Abstract This experimental test investigates the effect of filling ratio (FR) and inclination angle on the thermal performance of a nanoengineered copper-water heat pipe. A hydrophilic copper oxide coating (CuO) is synthesized and integrated on the inner wall of the evaporation section of the heat pipe. The heat pipe is fabricated from an inner grooved copper pipe with dimensions of 12.7 mm outer diameter, 11 mm inner diameter, and 440 mm length. Ultra-filtered de-ionized (DI) water is used as a working fluid. Four different FRs of DI water 3%, 5%, 10%, and 15% are investigated to determine the optimum configuration. All samples are tested at various inclination angles and working loads. Experimental results show that the optimum filling ratio is the 5% FR, which was indicated by the lowest thermal resistance of 0.019 K/W.

Mechanical Damage Protection Method by Reducing Induced Current in NI REBCO Pancake Coils During Quench Propagation

The no-insulation (NI) winding technique has been attracting attention, because NI Rare-Earth Barium Copper Oxide (REBCO) pancake coils have high thermal stability. It is an indispensable technology to generate an ultra-high magnetic field. In 2017, using the NI winding technique a world-record high magnetic field, 45.5 T, was generated by 12 insert single pancake coils with an outsert magnet, and it showed a high potential to generate 14.4 T inside a background field of 31.1 T. After the experiment, the REBCO tapes were mechanically damaged, so that the critical currents were deteriorated. A large current was induced in NI REBCO coils next to the quenched coil when one of multi-stacked NI REBCO pancake coils quenched, resulting in tape property degradation and irreversible mechanical damage. Therefore, in order to protect NI REBCO pancake coils during quench, it is desired to reduce the amount of induced current. To suppress an induced current, the idea of “magnetic dam” has been proposed previously. The idea is to use a copper pipe installed at the outside of NI REBCO pancake coils. However, the copper pipe just slowed the quench propagation. In this paper, we extended the method to decrease an induced current much more by installing extra NI REBCO windings instead of the copper pipe. The electromagnetic and stress behaviors of 6-stacked NI REBCO coils with extra windings are simulated when one of the stacked NI REBCO coils transitions into a normal state. The ability of mechanical damage protection from a strong stress by an induced current during quench propagation is demonstrated through simulations.

Photovoltaic thermal (PV/T) system assisted heat pump utilization for milk pasteurization

In this study, a hybrid photovoltaic-thermal heat pump system, supported by a four-pass economizer and a PV/T panel, has been installed to pasteurize milk to be processed into cheese. The surface temperature, which increases with the solar radiation value of the monocrystalline photovoltaic panel, has been decreased by transferring its heat to the water passing through the copper pipes that have been placed behind it. The study aims to try to increase the electricity generation by ensuring the cooling of the panel and while doing this, to make the thermal energy available for the pasteurization of milk, to meet some of the required energy from the PV/T system, to reduce the amount of energy consumed for pasteurization per unit of milk by shortening the pasteurization period, to increase system efficiency and focus on efficiency performances. The hybrid photovoltaic-thermal heat pump system has been compared with conventional methods. It has been determined that PV/T support and increasing raw (unpasteurized) milk flow from 120 l/h to 150 l/h have decreased the total pasteurization time and the thermal efficiency has increased by increasing the panel water flow. As a result of the experiments, it has been determined that the PV/T supported heat pump system has consumed approximately 73.3% less energy than the previously installed double-walled boiler system, 60.7% less than the plate pasteurizer system, and 25.5% less than the heat pump system. It has been determined that supporting the heat pump system established for pasteurization of milk with the PV/T system provides approximately a 8.8% reduction in the amount of energy consumed per kg milk.

Application of Thermoelectric Generator TEG Type Parallel Series Electric Circuit Produces Electricity from Heat Rocket Stove

In rocket stove, wood is burned in a simple combustion chamber. This combustion chamber is connected by chimneys and air holes. Several studies have been carried out to utilize the heat generated by combustion of rocket stove, namely thermoelectric generators. Thermoelectric generators are electrical generator devices that convert heat energy or temperature differences into electrical energy using a phenomenon called the seebeck effect. The thermoelectric generator used in this study is TEG SP1848. How this tool works is a compilation of combustion occurs on a rocket stove then the copper pipe which is wrapped around a rocket stove flowed by wateralso rises in temperature, and the circulation of water from the chamber passes through a copper pipe, within 30 minutes the water in the chamber reaches 90°C ± then it is done from the power generated by the TEG connection then the test is done by loading a resistor of 1kΏ-10kΏ the highest generator efficiency values obtained at the 5k ohm resistor reached 5.38% of the left TEG. For TEG the right side of generator efficiency tends to be stable. The highest value of the right-side TEG generator efficiency is obtained at 0.48% at 2k ohm resistance.

Simulation analysis of bio-oil from slow pyrolysis using palm empty fruit bunch

This study analyses the slow pyrolysis process of Palm Empty Fruit Bunches (EFB) from a temperature of 400-650°C in producing bio-oil in the Aspen Plus simulation. The study involves the effect of excess air for the combustion process to supply heat to be used by the pyrolysis process. From the analysis, it was found that the value of energy in the form of heat is present in high amounts if the excess air is around 40%. Heat is then used to heat the biomass, producing syngas, which then passes through a heat exchanger with a copper pipe with a length of 10 m in 200 liters of water. The bio-oil mass flow rate will decrease as the pyrolysis working temperature increased, from 0.38 kg/hour to 0.121 kg/hour, or 0.387 liters/hour to 0.124 liters/hour. The bio-oil heating value will increase with increasing pyrolysis temperature from 8713.68 J/kg to 27,130.92 J/kg, at 400 °C to 650°C, respectively. The amount of bio-oil mass-produced in the simulation compared to the yield during the experiment, and it was found that the simulation results were higher, around 39.08%. That is due to there is some bio-liquid stored at the bottom of syngas storage.

Influence of Cavity Materials and Selective Surface Coatings on the Performance of SCC

It is evident that the future energy demand can be compensated by using solar energy. The technological improvements are needed to trap the sunlight and have to be utilized in an efficient way. It mainly depends on the type of material which is to be used for this purpose. Solar energy can be effectively captured and utilized to heat the heat transfer fluids. Therefore the usage of solar energy is a right choice as it has the ample availability in countries like India.Solar cavity collector [SCC] is a kind of improvised, modified and redesigned construction of a solar Flat Plate Collector (FPC). In short, SCC is an upgraded and advanced version of FPC. A Copper pipe has been positioned concentrically fitted to a radius (outer) of 16 mm and placed into a metal box like structure having a size of 50 mm. In a similar way, five numbers of such cavities are formed. It has a provision for inlet and outlet water pipes. It has been designed, fabricated and experimented for its optimized level of performance. This paper explains about the usage of materials and solar selective surface coatings that are applicable to Solar Cavity Collector (SCC). The following experimental modifications are carried out in the SCC which are 1.Reciever materials of the SCC have been changed as aluminum and copper. 2. Cavity materials as Galvanized Iron (G.I) material and Mild Steel (M.S) material, both are experimented. 3. Solar selective coatings (SSC) of Black nickel have been used in SCC for the heat transfer improvement.