The operation processes of adsorptive solar refrigerators based on composite adsorbents ‘silica gel - sodium sulphate’ were studied. The correlation between the adsorbent composition and the coefficient of the energy performance of the device was stated. As a consequence of the decreasing of adsorbent mass, the coefficient of performance is increased when sodium sulphate content in the composite increased. Effect of the regeneration process parameters on the composite on the coefficient of performance of the adsorptive refrigenerator was stated. The growth of the coefficient of performance is shown to result from decreasing the difference between adsorbent temperature and regeneration temperature from 85 to 55°C. The maximum values of the coefficient of performance of studied solar adsorptive refrigenerator about of 1.14 are stated for composites containing about 20 wt. % silica gel and 80 wt. % sodium sulphate.

Exergy analysis of an open-mode adsorptive heat storage unit has been performed when a composite ‘silica gel – crystalline hydrate’ used as an adsorbent. The crucial factors affecting the exergy efficiency factor are stated to be temperature and initial humidity of airflow supplied to the inlet of adsorbent layer, temperature of external air and methods of air flow humidification. Procedure of calculation of the operating characteristics of an open-mode adsorptive heat storage device was further developed. The suggested procedure involves determination of adsorption, specific adsorption heat and final airflow temperature, useful heat, heat inputs for operating heat storage device and its efficiency factor, then exergy recovered, exergy supplied and exergy efficiency are calculated. Exergy efficiency depends on characteristics of flow of humid air fanned into the adsorbent layer such as temperature and initial absolute humidity which strongly affect the adsorption and final airflow temperatures. Increase of initial temperature of the humid air leads to decreasing of the exergy efficiency. Maximal values of exergy efficiency are determined at the absolute humidity and temperatures of initial airflow within the ranges of 0.03 – 0.04 kg/m3 and 20 – 30ºC, respectively. These characteristics are corresponded to the maximal airflow temperatures after passing through the adsorbent layer which meet to the Sanitary Regulations. Dependence of exergy efficiency vs. external air temperature and initial airflow temperature is shown. The exergy efficiencies of the open-mode adsorptive heat storage unit with steam and ultrasonic humidification were compared. Ultrasonic humidification is shown to allow increasing the exergy efficiency by 7 % against steam humidification. The obtained results can be used when energy-efficient heat and ventilation systems for residential premises developed.

Исследованы процессы эксплуатации адсорбционной холодильной гелиоустановки на основе композитных адсорбентов «силикагель -натрий сульфат». Получила дальнейшее развитие методика расчета адсорбционного солнечного холодильника. Проанализирован рабочий цикл солнечного адсорбционного холодильника. Установлены основные факторы, влияющие на холодильный коэффициент цикла адсорбционной холодильной гелиоустановки на основе композита «силікагель -сульфат натрия»: состав и адсорбционная емкость композита, определяющие его массу, разность температуры адсорбента и температуры регенерации. Выявлена корреляция между составом адсорбента и холодильным коэффициентом установки. Показан рост холодильного коэффициента при росте содержания сульфата натрия в композите, как следствие снижения массы адсорбента. Подтверждено влияние режима процесса регенерации композита на холодильный коэффициент установки. Показан рост величины холодильного коэффициента при снижении разницы температур адсорбента и температуры регенерации в интервале 85 -55 °С. Определено, что максимальные значения холодильного коэффициента 1,14 соответствуют разнице между температурой адсорбента и температурой регенерации, равной 55 °С, для композитов, содержащих около 20 масс. % силикагеля и 80 мас. % сульфата натрия.Ключевые слова: адсорбционный холодильник, композитный адсорбент, холодильный коэффициент, адсорбция, адсорбционная емкость, температура регенерации.