Experimental Study of a Solar Adsorption Refrigeration Unit, Factorial Analysis

The work is focused on the development of an effective algorithm for calculating the operational characteristics of a steamcompressive chilling machine with an adsorptive chilling unit, which involves a cold box, an adsorber, an evaporator and a condenser, water being used as a refrigerant. An algorithm for calculating the operating parameters of the adsorptive chilling unit has been developed, which includes the determination of the cooling capacity of the steam compressor refrigeration unit, the heat load on the condenser, the power consumed by the compressor, the coefficient of performance of the steam compressor refrigeration unit, as well as the calculation of the mass of water, the mass of the adsorbent, the refrigerating capacity, the coefficient of performance of the adsorptive chilling unit and the coefficient of useful energy utilization of a steam compressive chilling machine with an adsorption chilling unit. The chilling capacity and the coefficient of performance of the adsorption chilling unit are estimated under the operating conditions of a typical steam compression chilling machine. The crucial factors affecting the efficiency of the adsorptive chilling unit are analyzed. It has been established that the chilling capacity, the coefficient of performance of the adsorption refrigeration module and the energy efficiency of the installation are determined by the thermal load on the condenser, and, therefore, by the mass of water that is desorbed and evaporated. The coefficient of performance of the adsorption chilling unit and the efficiency of the steam compressor chilling machine with the adsorptive chilling unit are estimated to be 0.878 and 4.64. The criteria for the selection of adsorbents for the adsorption module are analyzed. The temperature of regeneration is determined by the temperatures in the condenser, and the limit adsorption affects the mass of the adsorbent and the size of the adsorber. A comparison of the efficiency of adsorptive chi l l ing uni t based on silicoaluminophosphates and composite adsorbents «silica gel – sodium acetate» is carried out. The prospects of using composites «silica gel – СН3СООNa» are shown. The optimal composition of the composite was established, which corresponds to the minimal size of the adsorber, (80% sodium acetate and 20% silica gel). The prospects of using adsorptive conversion of thermal energy for utilization of low-potential thermal energy during the operation of steam compressive chilling machine are shown. Keywords: adsorptive conversion of heat energy, composite adsorbent, steam compressive chilling unit, adsorption, adsorptive capacity.

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Comparison of an Adsorption Refrigeration Unit Operating with Two and Four Adsorbers

Proccedings of 10th International Conference "Environmental Engineering" ◽

10.3846/enviro.2017.257 ◽

2017 ◽

Author(s):

Andrzej Grzebielec

Keyword(s):

Cooling Capacity ◽

Adsorption Refrigeration ◽

Entire Process ◽

Refrigeration Unit ◽

Operating Unit ◽

Over Time

Adsorption refrigeration systems can be built with one, two or more adsorbers. The most common devices are built of two adsorbers. This fact makes the achieved cooling capacity is variable over time, and in some periods of operation is even 0 kW. Increased number of adsorbers causes the cooling capacity obtained in time is more balanced. The aim of the study is to compare the most popular operating unit with two adsorbers with the installation which continuously work with four adsorbers. It turns out that such a solution can align cooling capacity during the entire process. This solution does not affect the effectiveness of the device, but only on its size. Absorbers are the largest part of the device. So this type of solution is dedicated to wherever it is needed fluently providing cooling capacity and there is no possibility of collecting cooling in tanks.

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Energy Recovery Methods in Adsorption Refrigeration Units

Proccedings of 10th International Conference "Environmental Engineering" ◽

10.3846/enviro.2017.256 ◽

2017 ◽

Author(s):

Andrzej Grzebielec ◽

Adam Szelągowski ◽

Adam Ruciński

Keyword(s):

Energy Loss ◽

Thermal Wave ◽

Energy Recovery ◽

Type Systems ◽

Adsorption Refrigeration ◽

Wave Type ◽

Recovery Processes ◽

Refrigeration Unit ◽

The One ◽

Heat And Mass Recovery

Adsorption refrigeration systems, as opposed to absorption type operate in a cyclic manner. The result is that at the beginning of each process must be fed into the adsorber state in which they will adsorb or desorb a refrigerant. In the case of two adsorbers at the start of a cycle, the one of the adsorber must be refrigerated while the second has to be heated. These processes are causing unnecessary energy loss. The aim of the work is to show how these processes can be connected and the heat received from one adsorber is transported to another adsorber. As part of the study, the heat and mass recovery processes will be considered. It turns out that in the thermal wave type systems, it is possible to recover more than 25% of the energy lost to bring the adsorber to the states in which they will operate efficiently to desorb and adsorb refrigerant. That is, it is possible to improve the efficiency of the adsorption refrigeration unit using the proposed improvements.

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Possibility of using adsorption refrigeration unit in district heating network

Archives of Thermodynamics ◽

10.1515/aoter-2015-0019 ◽

2015 ◽

Vol 36 (3) ◽

pp. 15-24 ◽

Cited By ~ 6

Author(s):

Andrzej Grzebielec ◽

Artur Rusowicz ◽

Maciej Jaworski ◽

Rafał Laskowski

Keyword(s):

Air Conditioning ◽

District Heating ◽

Hot Water ◽

Transitional Period ◽

Heat Sources ◽

Adsorption Refrigeration ◽

Refrigeration Equipment ◽

A Value ◽

Refrigeration Unit ◽

Conditioning Equipment

Abstract Adsorption refrigeration systems are able to work with heat sources of temperature starting with 50 °C. The aim of the article is to determine whether in terms of technical and economic issues adsorption refrigeration equipment can work as elements that produce cold using hot water from the district heating network. For this purpose, examined was the work of the adsorption air conditioning equipment cooperating with drycooler, and the opportunities offered by the district heating network in Warsaw during the summer. It turns out that the efficiency of the adsorption device from the economic perspective is not sufficient for production of cold even during the transitional period. The main problem is not the low temperature of the water supply, but the large difference between the coefficients of performance, COPs, of adsorption device and a traditional compressor air conditioning unit. When outside air temperature is 25 °C, the COP of the compressor type reaches a value of 4.49, whereas that of the adsorption device in the same conditions is 0.14. The ratio of the COPs is 32. At the same time ratio between the price of 1 kWh of electric power and 1 kWh of heat is only 2.85. Adsorption refrigeration equipment to be able to compete with compressor devices, should feature COPads efficiency to be greater than 1.52. At such a low driving temperature and even changing the drycooler into the evaporative cooler it is not currently possible to achieve.

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