Numerical Evaluation of a HVAC System Based on a High-Performance Heat Transfer Fluid

Abstract

Nanofluids have great potential to improve the heat transfer properties of liquids, as demonstrated by recent studies. This paper presents a novel idea of utilizing nanofluid. It analyzes the performance of a HVAC (Heating Ventilation Air Conditioning) system using a high-performance heat transfer fluid (water-glycol nanofluid with nanoparticles of Al2O3), in the university campus of Lecce, Italy. The work describes the dynamic model of the building and its heating and cooling system, realized through the simulation software TRNSYS 17. The use of heat transfer fluid inseminated by nanoparticles in a real HVAC system is an innovative application that is difficult to find in the scientific literature so far. This work focuses on comparing the efficiency of the system working with a traditional water-glycol mixture with the same system that uses Al2O3-nanofluid. The results obtained by means of the dynamic simulations have confirmed what theoretically assumed, indicating the working conditions of the HVAC system that lead to lower operating costs and higher COP and EER, guaranteeing the optimal conditions of thermo-hygrometric comfort inside the building. Finally, the results showed that the use of a nanofluid based on water-glycol mixture and alumina increases the efficiency about 10% and at the same time reduces the electrical energy consumption of the HVAC system.

Experimental Evaluation of a Full-Scale HVAC System Working with Nanofluid

“…All the results shown in the above graphs demonstrate that the increased performance of the HVAC-2 system is not due to favorable environmental conditions, but only to the positive action of the nanofluid. The above discussed experimental results essentially agree with the numerical results found by Colangelo et al [37].…”

“…The results of this work suggest that the use of nanofluids within hydronic HVAC systems, can have a big impact under environmental, energetic and economic aspect. In fact, taking into account the annual energy consumption of the building "Corpo O" [37] it was possible to calculate annual energy savings equal to 50.2 MWh. Besides, according to the Italian CO2 emission factor [39], it was possible to preliminarily evaluate an annual avoided CO2 emission equal to 21.8 ton related to the use of nanofluid.…”

“…In order to overcome the above discussed problems, this work was based on a nanofluid composed by water-glycol and aluminum oxide (Al2O3) nanoparticles, having controlled size distribution (Dv90=617nm) and good stability, that deliver efficient, reliable and consistent performance over a wide temperature range, with little effects on viscosity, and, therefore, on system fluid pumping energy. Particularly, in [37] Colangelo et al developed dynamic simulations in order to compare the efficiency of two full-scale HVAC systems (installed at the educational building "Corpo O" in the Campus of University of Salento, Lecce -Italy), working with traditional water-glycol mixture and with Al2O3nanofluid: they found a numerical increment in efficiency of about 10%. As a follow-up to that study, the objective of this work was to carry out an extended experimental campaign on the same building, in order to quantify over a long period of time and under real operating conditions, the increase in performance of the HVAC system due to the use of nanofluid.…”

Assessment of a desiccant cooling system in a traditional and innovative nanofluid HVAC system

“…They are dilute suspensions of nanometer-sized particles or fibers dispersed in a liquid [2]. Many researchers have pointed out that the heat transfer performance of nanofluids is better than a pure heat transfer fluid [3], [4]. Sardarabadi et al [5], Zheng et al [6] and Buonomo et al [7] established that the addition of nanoparticles in base fluids improves their heat transfer and absorption characteristics and this good effect depends also on the volume fraction of nanoparticles.…”

Durum-Wheat Straw Bales for Thermal Insulation of Buildings: Findings from a Comparative Energy Analysis of a Set of Wall-Composition Samples on the Building Scale

“…In those studies, the authors often adopt dynamics codes, as it allows for the consideration of the actual heat exchanged by each building component. For instance, Colangelo et al [16] adopted the dynamics code for investigating the performance of heating/ventilation and air conditioning system (HVAC) with high-performance heat-transfer fluid (nanofluids), demonstrating how their new solution obtained a higher COP and EER and lower operating costs. Carlander et al [17] used dynamics simulations to highlight the dependence of the energy needs of a new office building on its indoor heat gains, location, orientation, and façade design.…”