Investigation of a Solar Cooling and Process Heat System in Hot Climates for Steam, Heat and Cold Supply in Industry
Abstract
This paper analyses a solar cooling system including a hybrid heat pump (HHP) and concentrating Fresnel collector plant of 400 m2 for industrial purpose at four different locations in hot climates (Barcelona in Spain, Johannesburg in South Africa, Mexico-City in Mexico and Cairo in Egypt). The HHP consists of adsorption chillers (AdC) and compressions chillers (CC) connected in series. This design combines the benefits of both technologies, as the solar thermally driven AdCs work in most efficient temperature levels and the CCs only provides the remaining cooling load. The TRNSYS simulation concluded that the operation in Johannesburg shows best performance in total numbers, accounting more than 160 MWh/a solar yield, as well as the steadiest provision of cold throughout the year. The AdCs in the system cause a significant increase of the electrical Energy Efficiency Ratio (EERel) of the CCs by up to 20 %. Furthermore, a connected steam network at the industrial sites serves as heat storage to provide stored solar heat even at night-time. That means that the solar thermally driven chillers have the potential to operate even in night times, resulting in most efficient operation thanks to lower ambient air temperatures. The COPth of the AdC is between 0.45 and 0.50 for Johannesburg and Mexico-City. The increased efficiency of the CCs and solar generated cooling capacity cause a reduction in electricity consumption. This again leads to potential savings of CO2 emissions. The calculated savings for Johannesburg account more than 50 t/a. The conclusion of the paper is, that the investigated solar cooling system shows best energetic and technical performance for applications in South Africa.
Keywords
Solar cooling, Solar process heat, Solar steam generation, Hybrid heat pump, Adsorption chiller, Heat rejection, Energy analysis, Trnsys, Steam network simulation