4. Energy-efficient AC systems

Numerous energy-efficient AC are working worldwide which are mainly based on evaporative cooling, adsorption, absorption, membrane, ejector, renewable energy, solar photovoltaic, solar thermal, low-grade waste heat, and hybrid technologies. From the perspective of nonhuman applications, this chapter focuses on low-cost AC systems particularly based on evaporative cooling and thermally driven technologies. The upcoming three headings discuss evaporating cooling options, followed next by the heating of thermally driven AC. Evaporative cooling is one of the ancient techniques (~2500 B.C.) for providing AC. It is popular worldwide (wherever applicable) due to its low-cost and simple designing. In principle, evaporative cooling produces the cooling effect by means of water vapor evaporation. In literature and worldwide market, numerous arrangements and designing of evaporative cooling systems are available. However, upcoming three headings are important from the subject of thermodynamic conception, that is, isenthalpic cooling [46, 47], sensible cooling, and dew-point (or below wet-bulb) cooling [10, 48, 49]. In order to highlight the significance of temporal and spatial variations on AC performance, 24 h–based ambient air conditions of two cities, that is, Multan (Pakistan) and Fukuoka (Japan), are investigated for nonhuman AC applications. Figure 6 shows ambient air conditions of both cities, archetypally for summer season [3].
