Development of “Low-tech” Solar Thermal Water Pumps for Use in Developing Countries

2004 ◽  
Vol 126 (2) ◽  
pp. 768-773 ◽  
Author(s):  
E. Orda ◽  
K. Mahkamov
Keyword(s):  
Developing Countries ◽  
Flat Plate ◽  
Thermal Water ◽  
Experimental Tests ◽  
Heating System ◽  
Solar Thermal ◽  
Solar Collectors ◽  
Dynamic Head ◽  
Simple Technology ◽  
Water Pumps

Solar water pumps, based on electro-mechanical pumps powered by PV arrays, are commonly used and commercially available. However, one of the difficulties for their wider application in developing countries, where there is a high average insolation, is their relatively excessive cost. This arises mainly due to the high cost of the PV elements. Hence, this paper describes some developmental work and results of experimental tests on “low-tech” solar thermal water pumps which were built on the basis of Stirling engines with fluid pistons coupled to flat-plate solar collectors. Temperatures and pressures in the cycle are comparatively low, thus cheap design materials, such as glass and plastic, and a simple technology, available in the majority of mechanical workshops, can be used for their manufacture and consequently reduce their cost. Several design modifications of the above solar thermal water pumps have been developed and tested. The results obtained demonstrate that existing installations can be effectively applied for water pumping with a dynamic head which varies between 2-5 m. Furthermore, data from experimental tests shows that the pulsating motion of water in channels of the flat-plate solar collectors increases the collector’s efficiency by approximately 8-10%, which is a considerable advantage when a pump is used as part of a house solar heating system.

Solar Thermal Water Pumps: A Preliminary Analysis of the Working Process

2005 ◽  
Vol 127 (1) ◽  
pp. 29-36 ◽  
Author(s):  
K. Mahkamov ◽  
E. P. Orda
Keyword(s):  
Mathematical Model ◽  
Thermal Water ◽  
Low Cost ◽  
Thermodynamic Cycle ◽  
Solar Thermal ◽  
Maximum Temperature ◽  
Working Fluid ◽  
Water Pump ◽  
Dynamic Head ◽  
Water Pumps

Solar thermal water pumps are low cost and low maintenance devices with a pumping capacity of 0.2-1m3/hour at a dynamic head of 1.5–5 m. The working fluid in the thermodynamic cycle is an air-steam mixture. In this paper we suggest a simple mathematical model to numerically simulate the internal processes in such a pump and determine the performance and physical dimensions of a preliminary design. The proposed mathematical model has been calibrated against experimental data and it provides the numerical simulation of the processes which occur in the cycle within an acceptable degree of accuracy for engineering purposes. The results of the analysis show that the performance of the solar water pump is mainly determined by the “steam” fraction of the cycle. The power of the solar thermal water pump increases with an increase in the maximum temperature in the cycle, while the indicated efficiency reduces because of the increase in the heat loss due to water vaporization and condensation processes.

scholarly journals Aplicaciones del Captador Solar de Placa Plana y del Captador de Tubo de Vacío en la Edificación = Applications of the Flat Plate Solar Collectors and the Vacuum Tube Solar Collectors in Building

2018 ◽  
Vol 4 (3) ◽  
pp. 25 ◽  
Author(s):  
Daniel Ferrández ◽  
Carlos Moron ◽  
Jorge Pablo Díaz ◽  
Pablo Saiz
Keyword(s):  
Flat Plate ◽  
Solar Collector ◽  
Energy Demand ◽  
Hot Water ◽  
Solar Thermal ◽  
Solar Collectors ◽  
Thermal Systems ◽  
Vacuum Tube ◽  
Solar Thermal Collectors ◽  
Flat Plate Solar Collector

ResumenEl actual Código Técnico de la Edificación (CTE) pone de manifiesto la necesidad de cubrir parte de la demanda energética requerida para el abastecimiento de agua caliente sanitaria y climatización de piscinas cubiertas mediante sistemas de aprovechamiento de la energía solar térmica. En este artículo se presenta una comparativa entre las dos principales tipologías de captadores solares térmicos que existen en el mercado: el captador de placa plana y el captador de tubo de vacío, atendiendo a criterios de fracción solar, diseño e integración arquitectónica. Todo ello a fin de discernir en qué circunstancias es más favorable el uso de uno u otro sistema, comparando los resultados obtenidos mediante programas de simulación con la toma de medidas in situ.AbstractThe current Technical Building Code (CTE) highlights the need to cover part of the energy demand required for the supply of hot water and heating of indoor swimming pools using solar thermal systems. This article presents a comparison between the two main types of solar thermal collectors that exist in the market: the flat plate solar collector and the vacuum tube solar collector, according to criteria of solar fraction, design and architectural integration. All of this in order to discern in what circumstances the use of one or the other system is more favourable, comparing the results obtained through simulation programs with the taking of measurements in situ.

scholarly journals Long-Term Performance of Anti-Freeze Protection System of a Solar Thermal System

Processes ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 1286
Author(s):  
Sebastian Pater
Keyword(s):  
Winter Season ◽  
Heating System ◽  
Protection System ◽  
Solar Thermal ◽  
Long Term Results ◽  
Solar Collectors ◽  
Evacuated Tube Collectors ◽  
Term Performance ◽  
Freeze Protection

In a moderate, transitory climate, to prevent freezing of outdoor pipes and collectors in solar thermal systems, anti-freezing fluids are commonly used. There is little experience of using water without any additives as a solar thermal fluid in such a climate. Based on these findings, to fill the knowledge gap this article presents the long-term results of thermal performance and anti-freeze protection of a solar heating system with heat pipe evacuated tube collectors with water as a solar thermal fluid. The operation of this system under real conditions was analysed for five years in southern Poland. The annual value of solar insolation ranged from 839 to almost 1000 kWh/m2. The monthly efficiency of the solar collectors from March to October was usually higher than 25%, and the lowest was between November and January. The anti-freeze protection system consumed annually from 7 to 13% of the heat generated by the collectors in the installation. Supporting the operation of the central heating system in the building during the winter season highly improved the efficiency of the solar collectors. Results show that it is possible to use water without any additives as a solar thermal fluid in a moderate, transitory climate.

An Investigation of a Residential Solar System Coupled to a Radiant Panel Ceiling

1988 ◽  
Vol 110 (3) ◽  
pp. 172-179 ◽  
Author(s):  
Z. Zhang ◽  
M. Pate ◽  
R. Nelson
Keyword(s):  
Heat Exchanger ◽  
Solar System ◽  
Flat Plate ◽  
Storage Tank ◽  
Heating System ◽  
Hot Water ◽  
Radiant Heating ◽  
Solar Collectors ◽  
Water Storage Tank ◽  
Radiant Panel

An experimental study of a solar-radiant heating system was performed at Iowa State University’s Energy Research House (ERH). The ERH was constructed with copper tubes embedded in the plaster ceilings, thus providing a unqiue radiant heating system. In addition, 24 water-glycol, flat-plate solar collectors were mounted on the south side of the residence. The present study uses the solar collectors to heat a storage tank via a submerged copper tube coil. Hot water from the storage tank is then circulated through a heat exchanger, which heats the water flowing through the radiant ceiling. This paper contains a description of the solar-radiant system and an interpretation of the data that were measured during a series of transient experiments. In addition, the performance of the flat-plate solar collectors and the water storage tank were evaluated. The characteristics of a solar-to-radiant heat exchanger were also investigated. The thermal behavior of the radiant ceiling and the room enclosures were observed, and the heat transfer from the ceiling by radiation and convection was estimated. The overall heating system was also evaluated using the thermal performances of the individual components. The results of this study verify that it is feasible to use a solar system coupled to a low-temperature radiant-panel heating system for space heating. A sample performance evaluation is also presented.

scholarly journals Thermo-Economic Analysis of Hybrid Solar-Geothermal Polygeneration Plants in Different Configurations

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2391 ◽  
Author(s):  
Francesco Calise ◽  
Francesco Liberato Cappiello ◽  
Massimo Dentice d’Accadia ◽  
Maria Vicidomini
Keyword(s):  
Flat Plate ◽  
Dynamic Models ◽  
Lithium Ion ◽  
Solar Thermal ◽  
Campi Flegrei ◽  
Condensation Temperature ◽  
Solar Collectors ◽  
Photovoltaic Panels ◽  
Geothermal Well ◽  
Solar Thermal Collectors

This work presents a thermoeconomic comparison between two different solar energy technologies, namely the evacuated flat-plate solar collectors and the photovoltaic panels, integrated as auxiliary systems into two renewable polygeneration plants. Both plants produce electricity, heat and cool, and are based on a 6 kWe organic Rankine cycle (ORC), a 17-kW single-stage H2O/LiBr absorption chiller, a geothermal well at 96 °C, a 200 kWt biomass auxiliary heater, a 45.55 kWh lithium-ion battery and a 25 m2 solar field. In both configurations, electric and thermal storage systems are included to mitigate the fluctuations due to the variability of solar radiation. ORC is mainly supplied by the thermal energy produced by the geothermal well. Additional heat is also provided by solar thermal collectors and by a biomass boiler. In an alternative layout, solar thermal collectors are replaced by photovoltaic panels, producing additional electricity with respect to the one produced by the ORC. To reduce ORC condensation temperature and increase the electric efficiency, a ground-cooled condenser is also adopted. All the components included in both plants were accurately simulated in a TRNSYS environment using dynamic models validated versus literature and experimental data. The ORC is modeled by zero-dimensional energy and mass balances written in Engineering Equation Solver and implemented in TRNSYS. The models of both renewable polygeneration plants are applied to a suitable case study, a commercial area near Campi Flegrei (Naples, South Italy), a location well-known for its geothermal sources and good solar availability. The economic results suggest that for this kind of plant, photovoltaic panels show lower pay back periods than evacuated flat-plate solar collectors, 13 years vs 15 years. The adoption of the electric energy storage system leads to an increase of energy-self-sufficiency equal to 42% and 47% for evacuated flat-plate solar collectors and the photovoltaic panels, respectively.

Performance of Flat-Plate and Compound Parabolic Concentrating Solar Collectors in Underfloor Heating Systems

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Sarvenaz Sobhansarbandi ◽  
Uğur Atikol
Keyword(s):  
Flat Plate ◽  
Solar Thermal ◽  
Concrete Slabs ◽  
Solar Collectors ◽  
Heating Systems ◽  
Circulating Water ◽  
Area Reduction ◽  
Floor Slabs ◽  
Common Area ◽  
Solar Thermal Collectors

There is a growing interest in using solar energy in underfloor heating systems. However, the large areas required for the installation of solar thermal collector's array can be discouraging, especially in the apartment buildings where the apartment's roof is a common area. The objective of this study is to investigate the possibility of using compound parabolic concentrating (CPC) solar collectors instead of the commonly used flat-plate collectors (FPCs) in such systems. It is aimed to explore the feasibility of area reduction required by the collectors. Second, the temperature profiles of circulating water loop and the concrete slabs are sought to be examined. The system consists of solar thermal collectors, a storage tank, and circulation of water to transport the heat to four similar floor slabs. The CPC collector outlet fluid's temperature can reach a maximum of 95 °C, compared to 70 °C obtained from the FPCs. The results from the simulations show that a 2 m2 CPC collector array can perform satisfactorily to match the job of an 8 m2 FPC array, obtaining the same required circulating water's temperature in the slabs.

Cost-Effectiveness of a Photovoltaic-Powered Heat Pump Water Heating System vs. Solar Thermal Water Heating

2009 ◽  
Author(s):  
Eric J. H. Wilson ◽  
John J. Burkhardt
Keyword(s):  
Life Cycle ◽  
Cost Effectiveness ◽  
Thermal Water ◽  
Cost Effective ◽  
Heating System ◽  
The Other ◽  
Cooling Effect ◽  
Solar Thermal ◽  
Water Heating ◽  
Pv System

The cost-effectiveness of a photovoltaic (PV) powered heat pump water heater (HPWH) system is compared to that of a traditional solar thermal water heating system. HPWH evaporators are most often located inside the conditioned building space, resulting in a year-round cooling effect in the building. This effect is beneficial during the cooling season but detrimental during the heating season. The significance of this cooling effect was evaluated as part of the life cycle cost (LCC) analysis of the PV-powered HPWH system. Four different locations were considered: Boulder, CO; Miami, FL; Chicago, IL; and Seattle, WA. For the solar thermal analysis, both electric resistance and gas-fired auxiliary water heating scenarios were considered. Life cycle costs for the PV-HPWH system were calculated for the case of a PV system dedicated to providing electricity for the HPWH, and for the case of a previously planned residential PV system being increased in size to accommodate the HPWH. This latter case uses a lower, incremental cost of increasing the size of the PV system. The most notable results of the analysis are summarized below: • In general, the solar thermal system is more cost effective than the PV-HPWH system, even using the incremental cost of increasing the size of a planned PV system. • In locations where there are incentives that apply to PV but not solar thermal systems, as in much of Colorado, the PV-HPWH system will be more cost-effective than solar thermal. • The cooling effect of the HPWH evaporator is a net benefit in Miami, FL, but a net penalty in the other three locations. • The PV-HPWH system becomes more cost-effective than solar thermal with gas auxiliary in Miami when the price of natural gas is increased from $1 to $1.50 per therm. • Increasing the price of gas in the other locations does not make the PV-HPWH system compete against solar thermal because the cooling effect penalty also increases with the price of natural gas.

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