Demonstration of a Solar-Driven Ejector Chiller Assisting the Air Conditioning System of a Building

Abstract

Days with greater amounts of sunshine often have higher cooling demands. This makes solar energy one of the best solutions to mitigate the use of fossil fuels in cooling systems. On the other hand, scientific studies on ejector technology have demonstrated promising improvements in terms of enhancing the efficiencies of cooling and refrigeration systems. This work involved field testing of a solar thermal plant combined with an ejector-compression system for space cooling applications in buildings. The thermal plant uses parabolic solar collectors that focus a large area of sunlight toward tubes where circulating oil captures the energy. This energy activates the ejector system, which produces a nominal 15-kW cooling effect. A solar ejector cooling system is integrated into the CanmetENERGY Research Centre's building, covering part of its air conditioning load, and consequently decreasing the electrical consumption of the main building's chiller. The system has operated with a coefficient of performance (COP) of up to 0.27 at this location. Design characteristics of the system are presented and the mode of operation and analysis of collected data are elaborated. Practical Application A practical application for ejector-based cooling systems (ECS) used in combination with solar energy is in the design of solar-powered air conditioning systems for homes or commercial buildings. These systems use solar thermal power to generate heat, which is then used to power an ejector cooling cycle that uses a combination of evaporative cooling and mechanical compression to cool the air inside the building. This can significantly reduce the need for electricity from the grid and help to reduce greenhouse gas emissions. Another practical application for ejector cooling systems working with solar energy is in the field of solar thermal power generation. Solar thermal power plants use mirrors to focus the sun's energy onto a fluid, which is then used to generate electricity. However, the high temperatures generated during this process can cause thermal stress on the system and reduce its efficiency. Ejector cooling systems can be used to cool the fluid and reduce thermal stress, increasing the efficiency of the power generation process. This can be done by using solar energy to power an ejector cooling cycle that uses a combination of evaporative cooling and mechanical compression to cool the fluid.