Liquid nitrogen energy storage for air conditioning and power generation in domestic applications

Highlights: • Current AC systems forms a major part of the energy consumed during peak times. • Liquid N₂ has been acknowledged as energy storage vector with high energy density. • It is feasible to use LN₂ to provide cooling and power for domestic applications. • The proposed technology saves up to 79% compared to the conventional AC systems. • The proposed system recovered about 85% of the energy stored in LN₂. - Abstract: The global demands for air conditioning have increased rapidly over the last few decades leading to significant power consumption and CO₂ emissions. Current air conditioning systems use mechanical vapour compression systems which consume significant amount of energy particularly during peak times and use refrigerants that have global warming potential higher than that of carbon dioxide. This paper presents a new approach for providing air conditioning and power using liquid nitrogen produced from surplus electricity at off peak times or renewable energy sources. Thermodynamic analyses of different cryogenic cycles was carried out to achieve the most effective configuration that provides the required cooling and power for a 170 m² dwelling in Libya with minimum LN₂ consumption. Results showed that at today LN₂ prices, it is feasible to use LN₂ to provide for cooling and power demands of residential buildings with saving of up to 28% compared to conventional AC systems. However, as the LN₂ price decreases to around 1.3 pence per litre, the proposed technology will have significant advantages compared to AC systems with savings of up to 79% with almost 85% of the energy stored in LN₂ is recovered.