Integrated Renewable Energy Options for HVAC-Cooling Systems

Abstract

The demand for energy is increasing at an unexpected rate all over the world. Most of the present worldwide energy usage is based on fossil fuel and results in continuous depletion of this resource. Conventional Heating Ventilation and Air conditioning (HVAC) cooling systems are the dominant source of power consumption. These systems have some problems such as low performance, high emissions, and high costs. So, more economically and environmentally friendly HVAC systems are desired which can provide the required power while saving energy and having high performance and low emissions to the environment. In this thesis, fuel cells and solar collectors are integrated with absorption cooling systems for sustainable development. This thesis examines the Coefficient of Performance (COP) and/or overall efficiency of a Proton Exchange Membrane Fuel Cell (PEMFC), Flat Plate Solar Collector (FPSC), Parabolic Trough Solar Collector (PTSC), and Photovoltaic-Thermal Collector (PV/T) integrated with Double Effect and Triple Effect Absorption Systems (DEAS and TEAS) to produce 10 kW of cooling capacity. A computer program is developed using Engineering Equation Solver (EES) software. The software is used to obtain all required thermodynamic properties of a water-lithium bromide (H2O/LiBr) solution and to carry out detailed energy and exergy analyses for each integrated system. The analyses show that the PEMFC system integrated with DEAS results in the highest COP. This is followed by the PV/T integrated with TEAS. The maximum energetic and exergetic COPs obtained for PEMFC integrated with DEAS are 2.70 and 2.30, respectively, while those obtained for PV/T integrated with TEAS are 2.32 and 2.06, respectively. However, the integration of PEMFC, PTSC, and PV/T with DEAS results in improved COP where the maximum energetic and exergetic COPs obtained are 2.94 and 2.50, respectively. Thus, this hybrid system is considered to be the optimum design from the performance point of view. This research provides a new interpretation of how alternative energy is utilized in operating HVAC cooling systems and presents a new insight into the most sustainable integrated systems that can be applied in residential and commercial buildings in the UAE.