Solar energy for cooling systems
Solar energy is a completely renewable energy resource that does not pollute the environment. These advantages make it worthwhile to utilise solar energy in a cost-effective and efficient manner. In response, a consortium of German, Spanish and Portuguese researchers created a solar-assisted gas-driven absorption cooling machine that can be used for the cooling purposes of many types of buildings. This new technology improves on the drawbacks of standard solar driven cooling machines. Current technology consists of a combination of a single effect absorption chiller (SE-AC) and furnaces that utilise oil or gas as fuel. When the solar heat supply is not sufficient for chilling, the system uses heat from the furnace for the absorption machine. Consequently, this switch in modes leads to a significant decrease in system efficiency. Therefore, these researchers aimed at designing an absorption cooling machine that is capable of utilising both solar energy from thermal collectors and natural gas in a way that exhibits a heightened system efficiency. With a simulation phase that examined the actual cooling demands of an ordinary house and a hotel for many Iberian cities, the resulting data were utilised as input for the simulation of three solar assisted cooling systems along with three solar collectors in order to compare the different energy and economic features. As a result, the most effective system was a mixed-mode single/double effect machine that yields the maximum energy savings along with a minimum increase in the yearly costs when compared to standard single effect devices. A prototype was developed and manufactured that optimises the thermohydraulic properties of the system for solar usage while maximising the commercial value of the system's design by building rectangular main heat exchangers that lead to very compact dimensions of the system. Moreover, the researchers want to increase the competitiveness of the European industry within the solar cooling and absorption chiller sectors. Also, the use of this technology could extend to the residential sector with the subsequent design of a small solar assisted absorption cooling machine. Another application is its use in developing countries. A pure solar cooling device could be developed for places where cooling in hospitals and food storage is a difficult task.
