Numerical Research of a Solar Driven Bubble Pump for Diffusion Absorption Refrigeration Systems

In conventional vapor compression and absorption refrigeration systems, a compressor or a mechanical pump, respectively circulates the refrigerant. Mechanical input, which is required by the compressor or the pump operation, contributes significantly to the noise level and lessens its reliability and portability. In contrast, diffusion absorption refrigeration (DAR) systems are heat-driven and contain no moving parts. Solar-driven diffusion absorption cooling system uses a low-grade heat to produce a cooling effect, and it's specially tuned for remote locations with high levels of solar radiation. This article studies the performance of a DAR system in Ashdod, Israel. Based on existing models in the literature and on experimental measurement of quantities such as the solar irradiance and the air temperature, the cooling capacity and the COP were simulated. Cooling capacity of the DAR system varies between 100 and 140 W, and COP between 0.09 and 0.17.

The Capability to Make Ice from Sunlight Utilizing a New Absorption Unit of Nano-Coated Ammonia/Calcium Chloride

In southern Jordan, the ice machine was designed, produced, operated, and fully examined at Mutah University, a unique Nano-coated ammonium/calcium chloride absorption sun unit. Analytical and experimental assessments on the use of ammonia/calcium chloride absorption unit ice produced. The new study has decreased energy emission by the Nano ice-making company while enhancing Nano's ice machine's nuclear power compared to standard solar chiller absorption that is not used in the current research. Our case was the world's first research to examine the effect of a nanoparticle combination of paint on an absorption cooling system used to make ice by the sunlight. The result of the test was quite encouraging. The combination of paint and nanofluid particle materials has boosted the accessibility to sun-based cooling processes and their capability to make ice of absorption. In addition, 0.6 was found to be a pretty good COP for the ammonia/calcium chloride solar system of absorption.

A Cascade Proportional Integral Derivative Control for a Plate-Heat-Exchanger-Based Solar Absorption Cooling System

Automatic proportional integral derivative control techniques are applied in a single-stage solar absorption cooling system, showing 3.8 kW (~1 ton) cooling capacity, with a coefficient of performance of 0.6 and −4.1 °C evaporator cooling temperature. It is built with plate heat exchangers as main components, using ammonia–water as the working mixture fluid and solar collectors as the main source of hot water. Control tuning was verified with a dynamical simulation model for a solution regarding mass flow stability and temperature control in the solar absorption cooling system. The controller improved steady thermodynamic state and time response. According to experimental cooling temperatures, the system could work in ranges of refrigeration or air-conditioning end-uses, whose operation makes this control technique an attractive option to be implemented in the solar absorption cooling system.

Analysis and Simulation of an Absorption Cooling System Using a Latent Heat Storage Tank and a Tempering Valve

The energy consumption for space cooling is growing faster than for any other end-use in buildings, more than tripling between 1990 and 2016. Energy efficiency is an important topic in the drive to reduce the consumption of electricity, particularly in air conditioning. This paper presents a simulation of an absorption cooling system with a parabolic trough collector under dynamic conditions using TRaNsient SYstem Simulation (TRNSYS) software. The thermal analysis seeks to evaluate a storage tank at three different configurations: (1) sensible heat, (2) latent heat, and (3) latent heat incorporating a tempering valve. The latent heat storage tank is a rectangular heat exchanger using MgCl2·6H2O as the phase change material, programmed in EES software; in addition, water and synthetic organic fluid were analyzed as heating fluids. The process was analyzed while varying the solar collector area from 20 to 40 m2 and the storage tank volume from 0.25 to 0.75 m3. The results showed that the solar collector of configuration 1 is unable to satisfy the energy demand. Configuration 2 can satisfy the demand with water and a storage tank volume above 0.50 m3 and 30 m2, while configuration 3 can satisfy the demand above 0.50 m3 and 20 m2 with water.