Effect of Operating Temperatures and Working Pairs on Performance of Solar Adsorption Cooling System

Renewable energies including solar energy requirements for refrigeration and air conditioning are increasingly gaining interest due to the refrigerants friendly to the environment. However, it was found that these technologies have some limitations like the low performance and their high cost. This paper proposes a comparative study of a solar adsorption refrigeration machine. The study consists in determining the influence of thermodynamic parameters of operation on the performance of the system. This is based on a thermodynamic model using different types of adsorbent / adsorbate pairs. The main parameters considered in this study are: temperature of generation, evaporation, maximum heating temperature, condensation pressure as well as the type of the pair used: activated carbon / methanol and zeolite / water. Simulations for different thermodynamic parameters show that the COP is very sensitive to the generation and evaporation temperatures as well as the maximum heating temperature, on the other hand it was slightly influenced by the condensation pressure. The results obtained have shown that the AC / methanol pair is more profitable than the zeolite / water pair.

Simulation and performance study of a two-bed adsorption cooling system operated with activated carbon-ethanol

This paper presents the transient model of a two-bed adsorption cooling system performed in the SIMULINK platform. The inlet chilled water temperature in the evaporator, temperature of cooling water and hot water temperature of the adsorbent bed and its effect on systems coefficient of performance, refrigeration effect and specific cooling power have been studied and presented. It is observed that the systems coefficient of performance is 0.57 when the inlet hot water temperature about 80 °C. In this study, the optimum cooling power and systems coefficient of performance are also determined in terms of the phase time, shifting duration and hot water inflow temperature. The results indicates that the cooling water and hot water inlet temperatures significantly affects the coefficient of performance, specific cooling power and cooling power of the system. The effect of mass flow rate on the cooler efficiency is also presented. A two bed adsorption system of capacity 13.5 kW having an evaporator and condenser temperatures of 6°C and 28°C, respectively, are considered for the present investigation. The adsorbent mass considered is 45 kg with a shifting duration of 20 sec. The result of this study gives the basis for performance optimization of a practical continuous operating vapour adsorption cooler.

Combined Cooling and Power Management Strategy for a Standalone House Using Hydrogen and Solar Energy

Tropical climate is characterized by hot temperatures throughout the year. In areas subject to this climate, air conditioning represents an important share of total energy consumption. In some tropical islands, there is no electric grid; in these cases, electricity is often provided by diesel generators. In this study, in order to decarbonize electricity and cooling production and to improve autonomy in a standalone application, a microgrid producing combined cooling and electrical power was proposed. The presented system was composed of photovoltaic panels, a battery, an electrolyzer, a hydrogen tank, a fuel cell, power converters, a heat pump, electrical loads, and an adsorption cooling system. Electricity production and storage were provided by photovoltaic panels and a hydrogen storage system, respectively, while cooling production and storage were achieved using a heat pump and an adsorption cooling system, respectively. The standalone application presented was a single house located in Tahiti, French Polynesia. In this paper, the system as a whole is presented. Then, the interaction between each element is described, and a model of the system is presented. Thirdly, the energy and power management required in order to meet electrical and thermal needs are presented. Then, the results of the control strategy are presented. The results showed that the adsorption cooling system provided 53% of the cooling demand. The use of the adsorption cooling system reduced the needed photovoltaic panel area, the use of the electrolyzer, and the use of the fuel cell by more than 60%, and reduced energy losses by 7% (compared to a classic heat pump) for air conditioning.