Analysis of the use of sorption and evaporative cooling as part of the preparation of ventilation air for Polish climatic conditions

Abstract

In this paper, the possibility of use of a DEC type air conditioning system, using solar energy, in Polish climatic conditions Polish, as an alternative to traditional systems based on compressor refrigeration equipment, was analyzed. At the beginning of the work, attention was paid to how important it is for users to maintain thermal comfort conditions and how these conditions can be determined. It also shows why the DEC system can be a good solution for the cases under consideration. In the next part of the paper, the analyzed system is described, presenting the individual processes of humid air transformation taking place in it, in which devices these processes can take place and how they were modeled in further calculations. Modeling the operation of the DEC system was based mainly on determining the efficiency of individual devices, i.e. the effectiveness of the processes taking place in them and the use of a psychometric graph. Similarly, the method of calculating the useful heat that can be obtained from solar collectors under known conditions is presented. For this purpose, meteorological data and the theory of similarity in heat transfer were used. In the next part of the work, an example of a calculation cycle was presented, along with the next steps of applying to the psychometric graph points corresponding to the states of moist air at individual points of the DEC system. On the basis of such calculation cycles, performed for different values of outdoor air parameters, the relationships of the obtained cooling power, the power supplied for adsorber regeneration, EER, temperature and relative humidity of the supply air to rooms, from the temperature and relative humidity of the outside air. Next, the calculation process for determining the useful heat obtained from solar collectors is presented. On the basis of several such processes, the average conditions of heat collection from the collector were determined, on the basis of which the amount of energy obtained from solar radiation was determined on the scale of the entire summer period. On the basis of this analysis, surpluses and shortages of energy obtained from collectors on individual days of the considered period were determined. In conclusion, it was stated that despite the fairly good cooperation of the system with solar collectors and its simple construction, the DEC system cannot be an alternative to compressor refrigeration equipment. This is mainly due to the unfavorable level of relative humidity in Polish climatic conditions, which does not allow the device to achieve the appropriate temperature of the air supplied to the rooms.