The criteria of adsorbent selection for adsorption transformers of thermal energy in ventilation systems are considered. The main characteristics of adsorbents that affected the structural parameters of the adsorption module are revealed. The method of determining the mass of the adsorbent and the volume of the adsorption unit in ventilation systems has been developed. The main factor affecting the volume of adsorbent is confirmed to be maximal adsorption. The advantages of ‘salt in the porous silica gel matrix’ composites are compared with traditional silica gels. On the example of an adsorption regenerator of low-potential heat and moisture, the greater effectiveness of the composites "silica gel-sodium sulphate" is shown in comparison with the composite 'silica gel - sodium acetate'. According to the experimental data on the operation of the adsorption regenerator of heat and moisture on the basis of the composite 'silica gel – CH3COONa', the adequacy of the proposed algorithm for determining the temperature efficiency factor has been confirmed. Suggested algorithm includes the calculation of the air volume passed through the layer of heat-storage material, water concentration in the air at the exit from the heat accumulator, adsorption, heat of adsorption, the final cold air temperature, air temperature after mixing cold air from the street and the warm air in the room at the inlet, the calculation of the concentration of water in the flow at the exit from the heat regenerator, the adsorption and heat of adsorption, the final temperature of the warm air, the air temperature after mixing the cold air from the street and the warm air from the room during the discharge, determination of the temperature efficiency factor, total adsorption and time to achieve the maximal adsorption. The efficiency of the processes of operating adsorption regenerators based on composites 'silica gel - sodium sulphate' and 'silica gel-sodium acetate' in the conditions of the typical ventilation system of housing premises was compared. The parameters that correspond to the maximum value of the temperature efficiency factors: the humid air velocity is about 0.22 - 0.32 m/s and the time of switching of the flows up to 5 minutes. The influence of meteorological conditions on the efficiency of the adsorption regenerator has been confirmed. The higher efficiency of adsorption regenerators based on 'silica gel - sodium sulphate' composites is explained, which is explained by higher values of maximal adsorption, which results in increasing the heat of adsorption. The results of the research can be used for the selection of adsorbents for energy-efficient heat energy converters in ventilation systems for residential and warehouse premises.

Operational parameters of adsorptive regenerator of low-potential heat and moisture based on composite adsorbents «silica gel-sodium sulphate» and «silica gel-sodium acetate» synthesized by sol-gel method were studied. Correlation of the parameters such as airflow rate, switching period, and temperatures of internal and external air, temperature efficiency factor was stated. Purposeful changing the temperature efficiency factor in rather wide ranges is shown when the switching period and airflow rate variated. Maximal values of temperature efficiency factors are stated at the airflow rates and switching over time of at most 0.22-0.32 m/s and 5-10 min., when composite «silica gel-sodium sulphate» used. Regenerators based on composites «silica gel-sodium sulphate» are stated to surpass devices based on «silica gel-sodium acetate» by at least 9-10 % of temperature efficiency factors. Efficiency of adsorptive regenerators is revealed to be affected by the meteorological conditions. Maximal values of temperature efficiency factor of regenerators based on composites «silica gel-sodium sulphate» are corresponded with the external air temperature of-5-0 °C and internal air temperature of 15-16 °C.

The performance of an adsorptive heat-moisture regenerator based on a silica gel–sodium sulphate composite adsorbent was studied. The correlation between the adsorbent composition and structural characteristics of the laboratory-scale device was investigated. An algorithm for the calculation of the efficiency factors of the adsorptive regenerator was further developed. The suggested algorithm calculates the operational parameters, including the temperatures, humidities and volumetric flows of internal and external air, and estimates the regenerator’s performance via temperature and moisture efficiency factors, total adsorption and time needed to achieve maximum adsorption, air pressure loss and fan power input. The validity of the calculation results obtained using the proposed algorithm was confirmed experimentally. Temperature efficiency factor, air pressure loss and fan power consumption are crucial parameters for the estimation of the optimal operating regime of an adsorptive heat-moisture regenerator. The correlation between meteorological conditions and efficiency factors was assessed and applied in a simulation of residential house-scale air conditioning unit operation. Maximal values of temperature efficiency factor were found at internal and external air temperatures of 15 to 20 °C and −5 to 0 °C, respectively. Moisture efficiency factors were observed to reach their maximum at the absolute humidities of external and internal air of 4.0 to 5.0 g/m3 and 2.75 to 3.0 g/m3, respectively. The fan power consumption of the adsorptive heat-moisture regenerator was found to be comparable to or even lower than that of commercial air conditioning units used in comparably voluminous interiors.

Thermal conditions of adsorptive heat storage device operating in open-mode were considered when discharged. The main operating parameters affecting the final temperature of airflow which supplied to ventilated premises are determined on the example of heat storage device based on composite ‘silica gel – sodium sulphate’. The main factors which determine a final airflow temperature are confirmed to be initial values of temperature, absolute humidity and speed of airflow which fanned to the adsorbent layer. Algorithm of calculating the operational parameters of adsorptive heat storage device has been further developed.  Proposed algorithm involves calculation of diffusion coefficient, mass transfer coefficient, final absolute humidity of airflow, volume of air which passed through adsorbent layer, adsorption, specific adsorption heat and final airflow temperature, then useful heat, heat inputs for operating heat storage device and its efficiency factor are estimated. The adequacy of the proposed algorithm has been confirmed according with experimental data for operating of open mode adsorptive heat storage device. Curves final temperature of inflowing air vs. time of discharge of heat storage device are stated to depend on characteristics of airflow which fanned to the adsorbent layer such as temperature, speed and initial absolute humidity. When these parameters increased, time to achieve plateau, i.e. maximal values of final inflowing air temperature decrease. The dependence of initial values of temperature, absolute humidity, speed of humid airflow and final airflow temperature is shown. Maximal temperatures of at most 65 – 80 ºC are stated at the initial temperatures and absolute humidity of initial airflow within the ranges of 20 – 30 ºC and 0.03 – 0.04 kg/m3, respectively. The results of the present study can be used for the development of energy-efficient systems and devices for air-conditioning in habitual inner space and warehouses.

This paper is devoted to performance of adsorptive heat energy converters for heat supply systems. The following calculation procedure of operating characteristics of an adsorption heat energy storage device for a decentralized space heating system is suggested: calculation of the mass transfer coefficient, adsorption amount, useful heat of adsorption, determination of the heat input, it being calculated as heat inputs for heating the adsorbent, device housing, water in the tank, evaporation of water in the tank, heating of the adsorbed water and desorption. Then coefficient of efficiency is calculated. The optimal operating conditions of the heat accumulating device which allow to operate with maximal efficiency coefficients 53 – 57 % are stated to be vapor-air flow rate 0.6 - 0.8 m/s and relative humidity of 40 – 60 %. Correlation between efficiency coefficients deduced from experiments and calculated with suggested algorithm is confirmed by the results of field trials.

The performance of the adsorptive heat-moisture regenerators based on the composite materials ‘silica gel - sodium acetate’ and ‘silica gel – sodium sulphate’ have been studied. The mathematical model and algorithm for determining the basic operating parameters of adsorptive regenerator in the housing and communal services sector have been further developed. The proposed algorithm which involves calculating the air volume passed through the adsorbent layer, the final absolute humidity of air near the outlet from the regenerator, the adsorption and the heat of adsorption  during inflow and outflow, the final temperature of the external cold air, the air temperature after mixing the cold external air and the internal warm air in the room near the warm end of the regenerator during inflow, the air temperature after mixing of the cold external air and the warm exhaust air from the premise near the cold end of regenerator during outflow, determining the temperature and moisture efficiency factors has been completed by computing the Reynolds criterion of the adsorbent layer, the coefficient of the hydraulic resistance, the pressure loss, the consumed power of ventilator, summarized adsorption and time to achieve maximal adsorption . The adequacy of suggested mathematical model is confirmed by sufficient correlation of experimental data and calculation results with the proposed algorithm. The performance of adsorptive regenerators based on the adsorbents ‘silica gel – CH3COONa’ and ‘silica gel – Na2SO4’ has been simulated in the conditions of the conventional ventilation system of living quarters. The efficiency of adsorptive regenerators has been compared when ‘silica gel – CH3COONa’ and ‘silica gel – Na2SO4’ used. The correlation of design and efficiency of adsorptive regenerators is shown.

The present work is focused on the performance of the adsorptive heat storage device based on the composite adsorbent "silica gel-sodium sulphate" for the decentralized heating system. The following algorithm for calculating of the efficiency factor of adsorptive heat storage device is proposed calculation of the volume of air passed through the adsorbent layer, absolute humidity of air on the outlet of heat storage device, adsorption, heat of adsorption, operational inputs, such as heating the adsorbent up to the temperature of the beginning adsorption. The correlation of the adsorbent composition and the design characteristics of the heat storage unit has been revealed. The most efficient thermal accumulators are shown to be based on a composite, such as 80% sodium sulphate and 20% silica gel, which corresponded with the maximal values of the limit adsorption. Simulation of the performance of heat storage device based on the composites "silica gel-sodium sulphate" was carried out in the conditions of a typical heating system of residual premises. It has been shown that with steam moistening, the maximal values of the efficiency factor are observed when maximal value of adsorption achieved, the temperature of the humid airflow of 50-60 °C, the relative humidity of 55-60%, airflow speed of 0,4-0,6 m/s. For the first time the structure of inputs for the performance of an adsorptive heat energy storage device was analyzed for steam and ultrasonic moistering. For the first time expediency of the ultrasonic moistering was shown as a method to increase the efficiency of the adsorptive heat storage device. The optimal operational parameters of the adsorptive heat storage device under ultrasonic humidifying: the airflow speed is of 0,2-0,4 m/s and the relative humidity is 40-60%. These parameters allows to enhance the efficiency of the adsorptive heat storage device. Results of the present study can be used to develop energy efficient systems of decentralized heat supply, as well as ventilation and air conditioning.

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