Integrating a nanofluid-based solar system with air handling unit to reduce energy usage: Case studies in Saudi Arabia

Background: In summer, the ventilation requirements of the supply air in the air handling units (AHUs) are adjusted using reheating coils. The water temperature in reheating coils is in the range that can be integrated with a solar heating system. Methods: In this study, the thermal behavior of nanofluid filled solar-assisted AHU was investigated. The first law of thermodynamics was developed considering two phases of vapor as well as air. Considering the Riyadh dew point temperature, vapor condensation was modeled in the cooling coil. Due to the time-dependent nature of solar radiation intensity, the energy, as well as continuity equations for the collector and stratified storage tank were approved. Findings: The results showed that the use of Al2O3 nano-scale particles increased the loss coefficient (undesirable), but due to the enhancement in maximum efficiency (desirable), nanoparticles intensified the annual collector effectiveness up to 6.1%. In July, integrating a nanofluid-based solar system with AHU, the energy demand reduced by 4700 kWh, which was equivalent to 17.9% reduction in the heating coil load. (c) 2021 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Automated summary

The study investigated the thermal behavior of nanofluid filled solar-assisted AHU and found that nanoparticles can increase annual collector effectiveness. Integrating a nanofluid-based solar system with AHU in July can significantly reduce energy demand.