Progress and latest developments of evacuated tube solar collectors

Sabiha, M.A.; Saidur, R.; Mekhilef, Saad; Mahian, Omid

doi:10.1016/j.rser.2015.07.016

Cited by 332 publications

(93 citation statements)

References 66 publications

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“…where taking into account Italian conditions and components characteristics the following assumptions, were considered: -lower heating value (LHV) of natural gas equal to 9.52 kWh/Nm 3 ; -the total volume of natural gas V NG,tot = ∑ r V NG,r = E th,B / (η B × LHV) should be divided according to the brackets of Table 5, to which different unitary costs (c NG,r ) are associated; -unitary cost of electricity (c el ) equal to €0.211/kWh; -extra cost of desiccant-based AHU with respect to the conventional one equal to €10,000, it also includes maintenance costs, as provided by the purchase contracts; -investment cost of storage tank equal to €3,000; -investment cost of chiller: €3,000 for the AS and €6,000 for the CS; -specific cost of collectors (c col ) equal to €360/m 2 and €600/m 2 for flat-plate and evacuated tube collectors, respectively; -maintenance cost of the boiler (MC B ) equal to €80/year; -maintenance cost of the chiller in the AS (MC AS chil ) equal to €150/year [29]; -maintenance cost of the SC (MC col = mc col × S × c col ) with specific maintenance cost mc col equal to 2% and S gross SC area [40];…”

Section: Model and Performance Assessment Methodologymentioning

confidence: 99%

Performance Assessment of a Solar-Assisted Desiccant-Based Air Handling Unit Considering Different Scenarios

et al. 2016

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Abstract:In this paper, three alternative layouts (scenarios) of an innovative solar-assisted hybrid desiccant-based air handling unit (AHU) are investigated through dynamic simulations. Performance is evaluated with respect to a reference system and compared to those of the innovative plant without modifications. For each scenario, different collector types, surfaces and tilt angles are considered. The effect of the solar thermal energy surplus exploitation for other low-temperature uses is also investigated. The first alternative scenario consists of the recovery of the heat rejected by the condenser of the chiller to pre-heat the regeneration air. The second scenario considers the pre-heating of regeneration air with the warmer regeneration air exiting the desiccant wheel (DW). The last scenario provides pre-cooling of the process air before entering the DW. Results reveal that the plants with evacuated solar collectors (SC) can ensure primary energy savings (15%-24%) and avoid equivalent CO 2 emissions (14%-22%), about 10 percentage points more than those with flat-plate collectors, when the solar thermal energy is used only for air conditioning and the collectors have the best tilt angle. If all of the solar thermal energy is considered, the best results with evacuated tube collectors are approximately 73% in terms of primary energy saving, 71% in terms of avoided equivalent CO 2 emissions and a payback period of six years.

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Section: Model and Performance Assessment Methodologymentioning

confidence: 99%

Performance Assessment of a Solar-Assisted Desiccant-Based Air Handling Unit Considering Different Scenarios

et al. 2016

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“…The solar collector is of great importance and works as the heart of the SWH system. The most diffused solar technologies are evacuated tube collectors in China and are flat-plate solar collectors in the rest of world [4]. However, for a conventional flat-plate solar collector, there are freezing problems when the ambient temperature is lower than zero, as well as corrosion problems when the water temperature is high and the pH departs from the neutral level [5].…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on a Forced-Circulation Loop Thermosiphon Solar Water Heating System

Zhang

2018

International Journal of Photoenergy

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Wickless gravity loop thermosiphons (LTs) have been widely used in heat collection for distances up to several meters. This twophase closed device, which is operating under reduced pressure, is useful in solar water heating (SWH) systems because it could address the freezing problem during winter. Compared to the normal type, forced-circulation wickless LTs have significant advantages in the long-distance heat transfer and installation freedom of condensation section. In this study, a pump-forced wickless LT-SWH system with a remolded flat-plate solar collector was put forward. Solar collector acted as the evaporation section of the wickless LT, while the spiral heat exchanger in the water tank acted as the condensation section. R600a was employed as the working fluid, and long-term outdoor experiments were carried out. Results show that the instantaneous and daily average photothermal efficiency of the proposed system can reach 69.54% and 58.22%, respectively. Temperature differences between the top and bottom and the middle and bottom of the evaporation section of the wickless LT were small, and it usually ranged between 1.1 and 3.9°C. Linear fittings of the collector and system overall performance of the pump-forced wickless LT-SWH system demonstrate the promising potential application of the system.

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“…[31][32][33] The authors used silicon solar cell as well as multijunction solar cell for PV module and analyzed the economical feasibility as well. Experimental and numerical researches were performed [34][35][36][37][38][39][40] based on PVT performance, system of pyramid-shaped solar water purification, solar collector of flat plate pattern, mini channel-based solar collector, evacuated tube, etc. The authors used different water-based nanofluids as well as water as heat transfer medium to enhance the thermal performance of the systems and reviewed the application of nanofluids on solar energy.…”

Section: Introductionmentioning

confidence: 99%

Effect of high irradiation on photovoltaic power and energy

2017

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Summary Solar photovoltaics (PV) is a promising solution to combat against energy crisis and environmental pollution. However, the high manufacturing cost of solar cells along with the huge area required for well‐sized PV power plants are the two major issues for the sustainable expansion of this technology. Concentrator technology is one of the solutions of the abovementioned problem. As concentrating the solar radiation over a single cell is now a proven technology, so attempt has been made in this article to extend this concept over PV module. High irradiation intensity from 1000 to 3000 W/m2 has been investigated to measure the power and energy of PV cell. The numerical simulation has been conducted using finite element technique. At 3000 W/m2 irradiation, the electrical power increases by about 190 W compared with 63 W at irradiation level of 1000 W/m2. At the same time, at 3000 W/m2 irradiation, the thermal energy increases by about 996 W compared with 362 W at 1000 W/m2 irradiation. Electrical power and thermal energy are enhanced by about 6.4 and 31.3 W, respectively, for each 100‐W/m2 increase of solar radiation. The overall energy is increased by about 179.06% with increasing irradiation level from 1000 to 3000 W/m2. It is concluded that the effect of high solar radiation using concentrator can significantly improve the overall output of the PV module.

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Progress and latest developments of evacuated tube solar collectors

Cited by 332 publications

References 66 publications

Performance Assessment of a Solar-Assisted Desiccant-Based Air Handling Unit Considering Different Scenarios

Performance Assessment of a Solar-Assisted Desiccant-Based Air Handling Unit Considering Different Scenarios

Experimental Study on a Forced-Circulation Loop Thermosiphon Solar Water Heating System

Effect of high irradiation on photovoltaic power and energy

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