# Evaluation of Coupling PV and Air Conditioning vs. Solar Cooling Systems--Case Study from Jordan
## 1 Introduction  
There is growing concern around the world about the consumption of fossil fuels. Studies have revealed that fossil fuel resources still constitute around 85% of the overall energy consumed, and buildings' energy consumption makes up around 20.1% of the overall delivered energy that is consumed globally [1]. To achieve a reduction in the proportion of fossil fuels consumed in this sector, the focus is increasingly turning to solar cooling. The estimates provided by the International Energy Agency (IEA) have been gradually increasing for many years, although they are yet to predict that photovoltaic (PV) technology will actually be deployed in each of their forecasts [2]. The IEA predicts that by 2050, PV technology will produce 4.7 terawatts according to its high renewable energyscenario, where in excess of 50% will be implemented in India and China, thus rendering solar power the leading source of energy in the world. Bloomberg expects there to be growth in the number of solar installations around the world in 2019, which will add 125-141 GW, leading to an overall capacity of 637-653 GW by year end [2]. The idea of solar cooling emerged on the basis of the presumption that solar energy could satisfactorily meet the cooling needs of buildings in hot summer periods, when both the solar radiation and ambient temperature reach their highest levels during the year. The coupling of solar power with cooling could make a significant contribution to lowering the elevated power demands of electricity grids and addressing the problem of climate change caused by global warming. In its current form, solar cooling predominantly comprises solar PV mechanical compression cooling and powered vapor compression cooling [3,4] using solar absorption [5, 6, 7] and solar desiccant cooling [8]. From these different options, the power for solar electric compression cooling systems is provided by PV technology, where such systems can either be connected to utility grids or stand alone. As PV systems can also be utilised for powering heat pumps to heat spaces within buildings, the integrated system can more appropriately be defined as being a photovoltaic air conditioner (PVAC). The other options utilise solar thermal energy and generally comprise a variety of different thermal collectors, including flat-plate collectors and evacuated tube collectors [9]. In PVACs, the energy can be supplied to the air conditioner by either the PV system or the power grid. Surplus PV power can be fed back into the grid in order to allow the PV system to continue working under the maximum peak power tracking (MPPT) function [10]. With regard to applications, PVACs connected to the grid are consistently perceived as being a component of the energy systems in buildings. Related studies concentrate on control strategies that are capable of smoothing the PV generation [11], increasing the cost-effectiveness [12] and enhancing the thermal comfort within buildings [13]. Stand-alone PVACs always include a system for storing energy that could be intended to either store electrical energy [14] or thermal energy [15]. Charging of the energy storage system occurs when the PV technology generates excess energy, whereas it is in a discharged condition when the solar radiation levels are reduced. The capabilities of cold storage batteries to save energy for stand-alone photovoltaic air conditioner systems were compared, which indicated that the energy-saving ability of the cold storage option was worse than the battery option because the coefficient of performance (COP) was comparatively low for air conditioners with cold storage. Nevertheless, stand-alone PVACs with batteries are not currently feasible in economic terms [16]. Both the generation of solar energy and the cooling demands of buildings are highly sensitive to local weather conditions. Associated studies are focused on the evaluation of different kinds of solar cooling approaches in different regions.