# Evaluation of Coupling PV and Air Conditioning vs. Solar Cooling Systems--Case Study from Jordan
## 1 Introduction
The consumption of auxiliary electricity in solar thermal cooling systems is largely for driving the system's fans and pumps. Solar energy can be converted into beneficial cooling or conditioned air (cooling and dehumidification) using various approaches. Combining photovoltaics and compression cooling additionally provides such benefits. Purely from the perspective of cooling, the amalgamation of photovoltaics and compression cooling could offer increased competition going forward. Nevertheless, the primary environmental benefit of solar cooling systems is not related to cooling, but rather the fact that such systems can be used for multiple purposes, including heating water and supporting heating, which could provide most of the CO\({}_{2}\) savings [29]. Numerous researchers have conducted studies on air conditioning and solar cooling driven by thermal energy. Solar thermal cooling can largely be categorised in terms of either closed or open cycles. In the former, which functions at atmospheric pressure, handling of the latent load is performed with liquid or solid desiccants. The sorbate is the water vapour from the environment, while the liquid or solid desiccant are the absorbent or adsorbent, respectively. Open processes comprise both evaporative cooling and sorption dehumidification, in which various interconnections can occur and a variety of sorbents are employed. The most frequently used techniques employ sorption rotors for dehumidifying. The rotor materials employed thus far have been limited to lithium chloride or silica gel, which are integrated into a cellulose medium. Various researchers have conducted studies in which liquid desiccants were applied to desiccant evaporative cooling systems, including [30; 31], while others have applied desiccant wheels, including [32; 33]. Closed processes involve absorption and adsorption chillers. In adsorption systems of refrigeration, the refrigerant is adsorbed using a solid. Commercially available devices predominantly utilise water and silica gel as the refrigerant and adsorbent, respectively [34]. The system's COP values are around 0.65 and heat from around 60 \({}^{\circ}\)C can be utilised to deliver cooling at reduced re-cooling temperatures [35; 36]. It is only possible to obtain a COP of 0.65 for an adsorption chiller when the desorption temperatures and cooled water temperatures are high but the cooling temperature is low. This value can be significantly lower when the heating temperature drops to 60 \({}^{\circ}\)C (ranging between 0.17-0.34) [36]. Such systems incorporate a particular functionality as a result of the regular desorption and adsorption of the sorbents. In general, two adsorbers function in an alternating manner, meaning that one of the adsorbers is always ready to provide cooling. This intermittent functionality causes the temperatures to fluctuate across a range of temperatures, which is a limitation that must be considered in the system design process [37]. The most common absorption chillers are the ammonia water (NH\({}_{3}\)-H\({}_{2}\)O) and water-lithium bromide (H\({}_{2}\)O-LiBr) systems. The former is used for refrigeration systems with usable temperatures under the point at which water freezes, while the latter is predominantly utilised in buildings' air conditioning systems. In the context of H\({}_{2}\)O-LiBr, the COP achieved by single-stage absorption chillers is generally around the nominal operating point of 0.7-0.8 and operative temperatures in excess of 75 \({}^{\circ}\)C are required [38]. In comparison to single-stage absorption chillers, dual-stage absorption chillers have an additional pair (generator and condenser), which means that the utilisation of the heat supply is increased. These types of systems are predominantly utilised for larger cooling capabilities and the COP values achieved range from 1.1-1.2. They generally require operative temperatures in excess of 140 \({}^{\circ}\)C [39].