Simulation of the performance and cost calculations of the surface pump

The photovoltaic (PV) energy has an important advantage to contribute in the socio-economic development of the remote regions and particularly in the Sahara areas. In Algeria a large number of PV pumps are used to supply water for drinking needs, irrigation, and many other purposes. These pumps are installed mostly in the large Algerian Sahara areas ; the submersible and the surface centrifugal pumps present the state-of-the-art for most applications. This paper presents the electrical and hydraulic performance of a surface centrifugal pump. The performances are calculated for three PV array sizes (1050, 1400 and 1750 Watts peak) and several total dynamic heads. The results which are analyzed are illustrated by tables and curves. The study of this surface pump shows the cost of the water per cubic metre for low total dynamic head (less than 14 metres) , thus it will be able to contribute in supplying water in the remote Sahara regions.     

Mathematic models of photovoltaic motor-pump systems

Photovoltaic (PV) pumping offers the possibility of supplying water to remote and desert regions for their daily needs. The sizing of the PV pumping systems is a very significant step in order to optimize the power peak of the PV array and to ensure the best choice of the motor, the pump and the inverter. Two mathematical models were proposed in this article to contribute in the studies of PV pumping sizing. These models link directly the operating electrical power to the water flow rate of the pump versus total head. These models are based essentially on the experimentation of pumps on CDER PV pumping test facility. Two pumping systems are tested: the first uses a centrifugal pump and the second uses a positive displacement pump. The results obtained by the models are very satisfactory. Also, the models enabled us to simulate the electrical and hydraulic performances of two tested pumps. The performances are calculated using the measured meteorological data of different sites located in Sahara and coastline regions of Algeria.     

The benefits of induced flow solar powered water pumps

This paper presents the case for using a novel type of solar water pump—the ‘induced flow’ pump. This type of pump is shown to be particularly appropriate for use with small, stand-alone units of up to 500 Wp, an area in which traditional solar powered water pumps do not excel. The pump is demonstrated to have performance characteristics combining those of centrifugal and reciprocating pumps over the full range of head and solar irradiance. Consequently the ‘induced flow’ water lifter offers considerable advantages over traditional, site-specific pumps and promises a significant advance in solar powered water pumping.     

Suitability of eccentric helical pumps for turbid water deep well pumping in photovoltaic systems

The inherently slim design of the eccentric helical pump appears to make this type of pump to be attractive for delivering water from deep wells, as compared with multistage centrifugal pumps. The basis shape of the volumeflow-head (V-H characteristics) of displacement pumps promises a more economical use of the available solar energy than possible with centrifugal pumps. This article presents the results of experiments concerning the wear in eccentric helical pumps operating with water containing abrasive particles. The temporary stability of the fluid flow and of the efficiency during delivery of abrasive suspensions is demonstrated. The results are used to derive a prognosis for the expectable service life of such a pump system.     

Modelling the integrated output of wind-driven roto-dynamic pumps

Roto-dynamic pumps offer better match with wind rotors for low lift-high discharge water pumping applications. Tremendous potential for such systems does exist in many developing countries like India. In the present study, a mathematical model is proposed for estimating the performance of wind-driven roto-dynamic pumps at various operating conditions. In contrast with the earlier attempts in this direction, an integrated approach incorporating the characteristics of the rotor, pump and the wind regime is envisaged for formulating the model. The model is validated using the field performance data from a 5 m, five-bladed experimental rotor coupled with a low speed centrifugal pump. Performance of the system at fluctuating conditions of wind regimes is estimated and compared with that of a system with reciprocating pump. Wind driven roto-dynamic pumps are found to offer distinctly better performance than the conventional system with reciprocating pumps. Effects of the specific speed and specific diameter of the pump on the gear ratio and optimum pump size are also discussed. A low specific speed roto-dynamic pump with reasonable specific diameter is found to be suitable for coupling with wind rotors for water pumping application.     

Performance analysis of mini centrifugal pump with splitter blades

Design method for a mini centrifugal pump is not established because the internal flow condition for these small-sized fluid machines is not clarified and conventional theory is not suitable for small-sized pumps. Then, a semi-open impeller for the mini centrifugal pump with 55mm impeller diameter is adopted in this research to take simplicity and maintenance into consideration. Splitter blades are adopted in this research to improve the per- formance and internal flow condition of mini centrifugal pump having large blade outlet angle. The performance tests are conducted with these rotors in order to investigate the effect of the splitter blades on the performance and internal flow condition of the mini centrifugal pump. A three dimensional steady numerical flow analysis is con- ducted to analyze rotor, volute efficiency and loss caused by a vortex. It is clarified from the experimental results that the performance of the mini centrifugal pump is improved by the effect of the splitter blades. Flow condition at outlet of the rotor becomes uniform and back flow regions are suppressed in the case with the splitter blades. Further, the volute efficiency increases and the vortex loss decreases. In the present paper, the performance of the mini centrifugal pump is shown and the flow condition is clarified with the results of the experiment and the nu- merical flow analysis. Furthermore, the performance analyses of the mini centrifugal pumps with and without the splitter blades are conducted.     

Assessment of solar applications for transfer of technology a case of solar pump

For the large and increasing rural population in the developming countries, decentralized solar applications could be relevant. However, new solar technologies being developed in the laboratories presently have to ultimately be acceptable in the field conditions. The conditions which have to be satisfied before the solar applications could be acceptable are discussed. The solar pump is examined in detail in particular due to the interest expressed by many developing countries in this specific application. A comparative techno-economic analysis is carried out for solar pumps and diesel pumps which considered escalation of the diesel price and factors related to climate, geography, locale, social and institutional environment for two types of uses namely for drinking water and for irrigation. It seems unlikely that a solar pump could compete with the diesel engine before the costs are brought down by a factor of 20–50 for irrigation purposes. However, for obtaining the drinking water the cost reduction required is by a factor less than 10 than currently charged for the prototypes. Although specific example of India is taken the matters are relevant to most developing countries. The issues discussed for the case of a solar pump are also relevant to other solar applications used only for seasonal purposes since the capital costs are high and operating diesel pumps during the season would be cheaper for several decades.     

Performance study of solar water pump using packed-bed collectors

In the present investigation solar water pumps using packed-bed collectors have been developed. It has been experimentally observed that the performance behaviour of such pumps is much superior to that of a solar water pump using conventional plain collectors. Among the solar water pumps developed, the one using iron-turning packed-bed collectors exhibits the best performance. It is interesting to conclude that the performance of a solar water pump using conventional (plain) collectors can be improved appreciably just by packing the collectors with metallic materials.     

Unsteady internal flow conditions of mini-centrifugal pump with splitter blades

Mini centrifugal pumps having a diameter smaller than 100mm are employed in many fields. But the design method for the mini centrifugal pump is not established because the internal flow condition for these small-sized fluid machines is not clarified and conventional theory is not suitable for small-sized pumps. Therefore, mini centrifugal pumps with simple structure were investigated by this research. Splitter blades were adopted in this research to improve the performance and the internal flow condition of mini centrifugal pump which had large blade outlet angle. The original impeller without the splitter blades and the impeller with the splitter blades were prepared for experiment. The performance tests are conducted with these rotors in order to investigate the effect of the splitter blades on performance and internal flow condition of mini centrifugal pump. On the other hand, a three dimensional unsteady numerical flow analysis was conducted to investigate the change of the internal flow according to the rotor rotation. It is clarified from the experimental results that the performance of the mini centrifugal pump is improved by the splitter blades. The blade-to-blade low velocity region was suppressed in the case with the splitter blades. In addition to that, the unsteady flows near the volute casing tongue were suppressed due to the splitter blades. In the present paper, the performance of the mini centrifugal pump is shown and the unsteady flow condition is clarified with the results of the numerical flow analysis. Furthermore, the effects of the splitter blades on the performance and the unsteady internal flow condition are investigated.     

Experimental investigation of solar powered diaphragm and helical pumps

For several years, many types of solar powered water pumping systems were evaluated, and in this paper, diaphragm and helical solar photovoltaic (PV) powered water pumping systems are discussed. Data were collected on diaphragm and helical pumps which were powered by different solar PV arrays at multiple pumping depths to determine the pumping performance, efficiency, and reliability of the different systems. The highest diaphragm pump hydraulic efficiency measured was ∼48%, and the highest helical pump hydraulic efficiency measured was ∼60%. The peak total system efficiency (e.g. solar radiation to pumped water) measured for the diaphragm and helical pumps were ∼5% and ∼7%, respectively (based on PV modules with ∼12% efficiency). The daily water volume of the three-chamber high head diaphragm pump performed better than the dual-chamber high head diaphragm pump (∼5 to ∼100% depending on PV array input power and pumping depth). Use of a controller was shown to improve the quad diaphragm pump performance below a solar irradiance of 600 W/m² (20 m head) to 800 W/m² (30 m head). While diaphragm pumps made mostly of plastic demonstrated similar to much better pumping performance than diaphragm pumps made with a high proportion of metal, the metal pumps demonstrated a longer service life (>2 years) than the plastic pumps service life (<2 years). Helical pumps analyzed in this paper were capable of deeper pumping depths and usually demonstrated a longer service life than the diaphragm pumps that were analyzed.     

Advances in solar water heating for domestic use in Australia

A method enabling retrofitting of solar collectors to existing domestic, low pressure electric water heaters has been developed and tested. The performance of the proposed system was found to be comparable with the performance of conventional solar water heaters when the size of the solar collectors is suitably matched to the average daily consumption of hot water. Other developments described are a solar energy operated pump and an airlift pump, both suitable for circulation of water in domestic solar water heaters, and an electronic controller for the circulating pumps.     

Performance of submersible PV solar pumping systems under conditions in the Sudan

Water pumping for domestic use and irrigation purposes can be considered as one of the basic needs in the rural areas of Sudan. For the favourable solar radiation conditions in the country (6 kW h/m²/day), solar water pumping may be a competitive application against diesel-driven pumps for remote areas.Three SP4–8 Grundfos submersible pumps, installed at three different locations in the country, were evaluated. Two of these pumps were driven by M-51 Arco Solar modules, while the third was driven by M-53 Arco Solar modules. For each of these pumps, solar radiation in the plane of the PV array, ambient temperature, PV array voltage and current, water discharge and water delivery pressure were monitored using a data logger.Grundfos solar pumps used in the Sudan have proven in most cases to be reliable. However, their performance was 10–25% less than predicted by the manufacturer's literature. In general the product of the daily water demand (m³ per day) and the total pumping head (m) should not exceed 750 m⁴ for sites with good solar radiation.     

离心泵叶轮内流动的油膜法测试

为了理解离心泵内部复杂的流动机理,揭示其内部的流动规律,以一叶轮形式为半开式的小型离心泵为例,采用表面油膜显示法,对其叶片及叶轮后盖板表面的流动情况进行了可视化试验研究。通过调整试剂成分比例,共设计6个试验方案,对比了不同油膜试剂的显示效果,并根据叶轮表面的流线分布对叶轮表面附近的流动情况进行了分析。试验结果证明了油膜显示法捕捉离心泵表面流动特征的可行性,为进一步理解离心泵内部复杂的流动机理提供依据。     

Analysis and simulation of a solar water pump for lift irrigation

A solar water pump for lift irrigation, which was shown to be economically viable, was proposed by Rao and Rao [5]. A “modified pump” is suggested, which is suitable for village water supply. The thermodynamic analysis of the pumps is presented. Though the solar water pump is intended to be operated with flat-plate collectors, it is analysed whether the pump could be run more efficiently when coupled with concentrating collectors. The analysis is also applicable for bellow actuated solar water pumps.Preliminary experimental studies showed that the heat losses are 2–3 times the theoretical energy requirement and the losses to the water tank shell accounted for a major part of the total heat losses. To reduce these losses, it is proposed that the inner surface of the water tank shell be lined with a resin bonded cork insulation. A method to evaluate the heat losses to the shell with insulation by solving the unsteady state heat conduction equation for a composite cylindrical body with time varying convective boundary conditions is presented. The heat losses are reduced to 5–15 per cent of the theoretical energy requirement with the use of the internal insulation. The major problem encountered in operating the pump was the inadequate condensation of the working fluid, which resulted in failure of the suction of water into the water tank. To ensure proper suction of water, the conditions to be maintained are analysed. The presence of water vapor and air in the spent vapor has to be taken into consideration while designing the condenser.An algorithm to evaluate the year round performance of the water-cooled pump for any location, given the lift and collector area, is presented. The cost of the water-cooled pump is compared with the costs of other types of solar water pumps and it is shown that the pump under consideration costs several times less than the other ones. The conditions at which the pump will be economical vis-a-vis diesel and electrical pumps are presented.     

Alternative technologies for US residential water heating : Energy savings and economic benefits

This article evaluates the energy savings and direct economic benefits of introducing heat pump and solar water heaters to the US residential market and the effects of a tax credit for solar installations. Energy savings are estimated for ten regions of the USA, as well as for the country as a whole, over the period 1977–2000. Changes in annual fuel bills and capital costs for water heaters are also computed. The results suggest that heat pump water heaters are likely to offer much larger benefits than solar heaters, even with tax credits. This is because heat pumps provide the same electricity savings (about 50%), but at a much lower capital cost.     

Installation and operation of the first city centre PV monitoring station in the United Kingdom

Recent interest in the application of PV in buildings throughout northern Europe has developed a need for long-term records of the solar resource in urban situations. Previous records have usually been collected from locations quite remote from city centre sites and, furthermore, at hourly sampling frequencies which are not rapid enough for photovoltaic applications. The installation of a photovoltaic monitoring station in a city centre in the north-east of England is described. Weather monitoring instruments were installed to measure ambient temperature, wind speed and direction, relative humidity and solar irradiance. Four types of photovoltaic modules are mounted on the rig in typical buiding orientations in order to assess their performance with respect to PV cladding applications. Preliminary investigations have shown that the electricity generated by PV cladding on vertical surfaces experiences much less seasonal variation than that on a horizontal surface. The performance of north and south facing modules has also been compared and this has shown that the north facing modules generate reasonably large amounts of electricity, particularly during the summer months. The proportion of diffuse irradiance on a north facing surface has been studied and quantified for various amounts of global horizontal irradiance. Analysis of the cadmium telluride modules has confirmed a better response to diffuse irradiance than the silicon modules and records of the amorphous silicon module show no evidence of cell degradation.     

Improving the effectiveness of solar pumping systems by using modular centrifugal pumps with variable rotational speed

The possibility of improving the performance of deep well solar pumping systems by using centrifugal pumps with variable rotational speed and modular number of working stages (i.e. Divided Shaft Pump, DSP) was investigated and compared with traditional systems equipped with pumps having a fixed number of stages (i.e Standard Centrifugal Pump, SCP). Starting from commercially available pumps with a given head–mass flow characteristic, a visual simulation tool for the evaluation of the modified DSP pump performance and costs was developed. In principle, it would be possible to use the desired number of modular stages, thus achieving the highest efficiency of the system for all conditions of radiation. In practice, in order to reduce the DSP pump costs to an affordable level, only one shaft breakpoint is suggested (and then two modular blocks of stages), whose optimised position is determined by the simulation program on the basis of insolation curve during the daylight and required head and shaft speed.Referring to a 30 m² PV system (about 3000 W peak power) and to a well depth of 100 m and considering a commercial 46-stage submersible pump, it was found that a breakpoint at the 31st impeller produced an increase close to 9% of the yearly pumped water yield with respect to a conventional, non-modular pump.For the above system, assuming that the cost of a modified modular pump is 1.5 times higher than that of a standard pump, the payback time varies from 0.5 to 2.5 years when the water sale price ranges between 1.1 and 0.6 €/m³.     

Energy consumption of a residential building: comparison of conventional and RES-based systems

The energy needs of a typical one-family house in the Thessaloniki area for heating, cooling and domestic hot water production are calculated. The calculations are based on the typical average daily consumption of hot water and on the degree-day method for heating and cooling. The results are finally translated into thermal energy consumption, assuming the typical Greek situation (heating with diesel oil boilers and conventional radiators, cooling with local air-to-air split-type heat pumps and hot water production with electric heaters). The same energy needs are assumed to be covered by a vertical closed loop ground heat exchanger combined with a water-to-water heat pump system with fan-coils for heating and cooling and a thermosyphonic solar system for domestic hot water production. The ground heat exchanger/heat pump system efficiency is determined using data from an existing and continuously monitored similar system installed in the broader area of Thessaloniki. The solar system load coverage is calculated using the f-chart method. The energy consumption of the renewable energy systems is calculated and compared to that of the conventional system. The results prove that significant energy savings can be achieved.     

Effects of the geometrical conditions on the performance of a side channel pump: A review

The side channel pump, which is a common energy conversion equipment, has undergone high developmental trends and has become very popular in recent times because of its wide applications in many fields. The side channel pump is a type of regenerative pump that plays a role in between the centrifugal pump and the positive displacement pump. This kind of pump delivers a high head at relatively small flows compared with other axial and centrifugal pumps even though it requires a low specific speed. Depending on the number of impellers used, the side channel pump can be single‐stage or multistage. This paper first focuses on the physical principle behind the internal flow characteristics illustrating the complex flow and the energy from the blade to the fluid and the side channel inside the pump. Further discussions disclosed that the hydraulic performance of the pump greatly depends on the variations of the geometrical parameters. This review draws conclusion that enhancement of the computational modeling techniques will improve the efficiency of this pump, thereby broadening its applications.     

从大型潜水电泵应用看泵站技术发展

通过宁夏扶贫扬黄灌溉一期工程首级泵站泵型比较,认为大型潜水电泵在可靠性、安装性、运行管理、自动保护以及经济性方面均达到或超过卧式中开离心泵,是具有广泛应用前景的泵型。同时对加快大型潜水电泵应用提出了一些建议。