scholarly journals Photovoltaic Evaporative Chimney I–V Measurement System

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8198
Author(s):  
Pablo Casado ◽  
José M. Blanes ◽  
Francisco Javier Aguilar Valero ◽  
Cristian Torres ◽  
Manuel Lucas Miralles ◽  
...  
Keyword(s):  
Measurement System ◽  
Cooling System ◽  
Local Maximum ◽  
Water Stream ◽  
Solar Cooling ◽  
Curve Tracer ◽  
Current Voltage ◽  
Capacitive Load ◽  
Final Design ◽  
Solar Cooling System

The photovoltaic evaporative chimney is a novel solar-cooling system that serves a double purpose: it increases the efficiency of the photovoltaic (PV) panels and it cools down a water stream which can be used to dissipate the heat from a refrigeration cycle. One of the major issues arising from the operation of the chimney is the temperature stratification in the panel due to the movement of the air in the chimney. This effect can trigger the activation of the bypass diodes of the module, creating local maximum power points (MPP) that can compromise the grid-tied inverter tracking. To fill this gap, this paper deals with the design and implementation of an I–V curve measurement system to be used in the performance analysis of the system. The I–V curve tracer consists of a capacitive load controlled by a single board computer. The final design includes protections, capacitor charging/discharging power electronics, remote commands inputs, and current, voltage, irradiance, and temperature sensors.The results show that the modules bypass diodes are not activated during the tests, and no local MPPs appear. Moreover, the curves measured show the benefits of the photovoltaic chimney: the cooling effect increases the power generated by the PV panels by around 10%.

scholarly journals A solar air-cooled high efficiency absorption system in dry hot climates: Reduction of water consumption and environmental impact

2018 ◽  
Vol 22 (5) ◽  
pp. 2151-2162
Author(s):  
Jose Marcos ◽  
Raquel Lizarte ◽  
Fernando Varela ◽  
Maria Palacios-Lorenzo ◽  
Ana Blanco-Marigorta
Keyword(s):  
Water Consumption ◽  
High Efficiency ◽  
Cooling System ◽  
Double Effect ◽  
Environmental Benefits ◽  
Absorption System ◽  
Solar Cooling ◽  
Single Effect ◽  
Solar Cooling System

A solar cooling system with an optimized air-cooled double-effect water/LiBr absorption machine is proposed as a sustainable alternative to meet cooling demands in dry hot climates. This system allows eliminating the cooling towers in those regions of the planet where water is scarce. This work analyses the environmental benefits of this air-cooled system, as well as its environmental foot-prints, compared to a solar water-cooled single effect. In this regard, a methodology has been applied to calculate the annual saving in water consumption produced in a case study: a hospital located in Almer?a, in South of Spain. Further-more, the reduction in energy consumption and CO2 emissions is also quantified since this machine can be driven by solar energy and with higher efficiency than those of single effect.

Simulation and Experimental Analysis of a Solar Driven Absorption Chiller With Partially Wetted Evaporator

2008 ◽  
Author(s):  
Jan Albers ◽  
Giovanni Nurzia ◽  
Felix Ziegler
Keyword(s):  
Cooling System ◽  
Cooling Water ◽  
Hot Water ◽  
Absorption Chiller ◽  
Efficient Operation ◽  
Part Load ◽  
Solar Cooling ◽  
Wetted Area ◽  
Solar Cooling System ◽  
Load Conditions

The efficient operation of a solar cooling system strongly depends on the chiller behaviour under part-load conditions since driving energy and cooling load are never constant. For this reason the performance of a single stage, hot water driven 30 kW H2O/LiBr-absorption chiller employed in a solar cooling system with a field of 350 m2 evacuated tube collectors has been analysed under part-load conditions with both simulations and experiments. A simulation model has been developed for the whole absorption chiller (Type Yazaki WFC-10), where all internal mass and energy balances are solved. The connection to the external heat reservoirs of hot, chilled and cooling water is done by lumped and distributed UA-values for the main heat exchangers. In addition to an analytical evaporator model — which is described in detail — experimental correlations for UA-values have been used for condenser, generator and solution heat exchanger. For the absorber a basic model based on Nusselt theory has been employed. The evaporator model was developed taking into account the distribution of refrigerant on the tube bundle as well as the change in operation from a partially dry to an overflowing evaporator. A linear model is derived to calculate the wetted area. The influence of these effects on cooling capacity and COP is calculated for three different combinations of hot and cooling water temperature. The comparison to experimental data shows a good agreement in the various operational modes of the evaporator. The model is able to predict the transition from partially dry to an overflowing evaporator quite well. The present deviations in the domain with high refrigerant overflow can be attributed to the simple absorber model and the linear wetted area model. Nevertheless the results of this investigation can be used to improve control strategies for new and existing solar cooling systems.

Impact of a vertical geothermal heat exchanger on the solar fraction of a solar cooling system

2017 ◽  
Vol 76 ◽  
pp. 63-72 ◽  
Author(s):  
A. Acuña ◽  
F. Lara ◽  
P. Rosales ◽  
J. Suastegui ◽  
N. Velázquez ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Cooling System ◽  
Geothermal Heat ◽  
Solar Cooling ◽  
Solar Fraction ◽  
Geothermal Heat Exchanger ◽  
Solar Cooling System

Design and test results of a low-capacity solar cooling system in Alicante (Spain)

Solar Energy ◽  
2012 ◽  
Vol 86 (10) ◽  
pp. 2950-2960 ◽  
Author(s):  
Pedro J. Martínez ◽  
José C. Martínez ◽  
Manuel Lucas
Keyword(s):  
Cooling System ◽  
Test Results ◽  
Solar Cooling ◽  
Solar Cooling System
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