A review on solar-powered cooling and air-conditioning systems for building applications

In a pilot installation at Hamburg University of Technology the coupled operation of an open cycle desiccant assisted air conditioning system with borehole heat exchangers is investigated. The paper presents experimental data recorded during the cooling period 2014. Results show that the electricity demand of the system can be reduced to the parasitic consumption of the fans, wheels and pumps. An electric energy efficiency ratio of 6.63 is achieved, enabling electricity savings of more than 70% compared to a conventional reference system and 54% compared to a desiccant assisted hybrid system relying on an electric chiller. Comfort conditions can be maintained during the whole cooling period. The borehole heat exchangers work highly efficient, exhibiting a seasonal performance factor of 192.

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Experimental investigation of a ground coupled desiccant assisted air conditioning system during winter mode

Hydrogen energy storage optimization in solar-HVAC using Sutterby nanofluid via Koo-Kleinstreuer and Li (KKL) correlations model: A solar thermal application

Heating and cooling (H/C) represent the largest share of energy consumption worldwide. Buildings are the main consumers of H/C, while the share of renewable energy for H/C provision still represents a low percentage, 22.0% in 2019. Hybrid photovoltaic-thermal (PV-T) systems are gaining increasing attention both in research and in applications, as they generate both electricity and useful heat simultaneously. The relevance and potential of PV-T collectors and their integration into wider systems are evident, but there is still a lack of review articles that address the potential of these systems in building applications in a comprehensive way. This work aims to review the state-of-the-art of PV-T collectors for building applications, as well as the corresponding PV-T systems for solar combined cooling, heating and power (S-CCHP) provision. The novelties of this work involve the comparison of these systems with conventional solar H/C technologies, the review of the market of H/C technologies, a summary of the challenges for the wider integration of S-CCHP systems and proposal lines of work to improve the cost-competitiveness of these systems. The first section summarises the focus and findings of previous reviews, followed by an overview of the current development status of the main types of PV-T collectors. Then, PV-T-based S-CCHP systems are reviewed, and the potential of PV-T systems’ penetration in the built environment is evaluated and discussed.

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Photovoltaic-Thermal (PV-T) Systems for Combined Cooling, Heating and Power in Buildings: A Review

Sustainable buildings have recently become a global priority. In hot climates, meeting the cooling demand in the sustainable buildings is challenging. To meet this demand in office buildings during summer, the study proposed a holistic configuration of applying passive solar design strategies (PSDSs), and then integrating an active solar cooling technology (ASCT) into the facade. Three hot climates, namely, humid subtropical, hot semi-arid, and hot desert, were investigated using a building energy model. First, four PSDSs, window-to-wall ratio (WWR), glazing type, shading devices, and wall material were sequentially applied to the facade. Then, an absorption chiller driven by a solar thermal collector (STC) was integrated into this passively designed façade. The best tilt angle, area, and dimensions of STC were specified for the main façade orientations. Finally, this study provides design guidelines for integrating ASCT into passively designed façade of office buildings in hot climates. The results reveal that WWR has the highest impact on the cooling demand reduction, whereas the least effect results from the shading devices. The passively designed facade reduces the cooling demand by 43.5%–65.7%. The sloped STC at a tilt angle of 30° is the most efficient option for all orientations except the north where the horizontal STC is considered the best. For these tilt angles, STC area required for meeting the cooling demand ranges from 2.88 m2 to 4.5 m2, corresponding to an STC-to-façade width ratio of 74.1%–84.3%. In the case of the vertical STC, the ASCT is unable to meet the cooling demands. 

Integration of active solar cooling technology into passively designed facade in hot climates

Conventional energy consumption in refrigeration is one of the important reasons in global warming. Solar cooling systems are becoming more compact, having lower costs, and are potential alternative technologies, especially in hot and sunny climates. The adsorption, absorption, and dissociative evaporative cooling (DEC) are the technologies used for sorption machines, which are discussed in this review paper. Various multi-criteria performance indicators appearing in the previous studies are discussed, followed by evaluating the benefits and drawbacks of distinguishing sorption solar thermal cooling systems. Market research is conducted to prove the capacity of these technologies. The review shows that compared to other technologies, the solar absorption system is more efficient, so it is very commonly used for cooling applications in various locations. An important topic was also presented using phase change materials and nanofluids in solar sorption systems, that need more research. It is noted from this that most solar cooling systems are hybrid in terms of source and there are multiple applications (cooling - heating and electricity generation). The software packages to study these systems are introduced. Further research is required on desiccant materials that can be regenerated under lower temperatures that would augment the extent of solar desiccant cooling application.

S. Suyambazhahan

Papers

Thermal solar sorption cooling systems, a review of principle, technology, and applications