Thermo-Economic Evaluation of Aqua-Ammonia Solar Absorption Air Conditioning System Integrated with Various Collector Types.

Adil Al-Falahi,Bernd Epple,Falah Alobaid

doi:10.3390/e22101165

Abstract

The main objective of this paper is to simulate solar absorption cooling systems that use ammonia mixture as a working fluid to produce cooling. In this study, we have considered different configurations based on the ammonia–water (NH3–H2O) cooling cycle depending on the solar thermal technology: Evacuated tube collectors (ETC) and parabolic trough (PTC) solar collectors. To compare the configurations we have performed the energy, exergy, and economic analysis. The effect of heat source temperature on the critical parameters such as coefficient of performance (COP) and exegetic efficiency has been investigated for each configuration. Furthermore, the required optimum area and associated cost for each collector type have been determined. The methodology is applied in a specific case study for a sports arena with a 700~800 kW total cooling load. Results reveal that (PTC/NH3-H2O)configuration gives lower design aspects and minimum rates of hourly costs (USD 11.3/h) while (ETC/NH3-H2O) configuration (USD 12.16/h). (ETC/NH3-H2O) gives lower thermo-economic product cost (USD 0.14/GJ). The cycle coefficient of performance (COP) (of 0.5).

Highlights

In recent years, the predominant technology in cooling systems worldwide is the conventional vapor compression cycle, which is known for its significant consumption of electricity due to the existence of a compressor and extremely high peak loads on the hottest summer days [1,2]
The results reveal that parabolic trough collectors combined with H2 O–LiBr (PTC/H2 O–LiBr)gives lower design aspects and minimum rates of hourly costs (USD 5.2/h), while Evacuated tube collectors (ETC)/H2 O–LiBr configuration give USD 5.6/h
The main objective of this work is to optimize and design NH3 -H2 O absorption air conditioning systems that are operated by different types of solar collectors (ETC and PTC), based on energy, exergy, design, and cost

Summary

Introduction

The predominant technology in cooling systems worldwide is the conventional vapor compression cycle, which is known for its significant consumption of electricity due to the existence of a compressor and extremely high peak loads on the hottest summer days [1,2]. Solar energy is an attractive solution for operating air conditioning systems. It saves electricity and primary energy sources (natural gas or oil), and decreases the emission of air-polluting gases and greenhouse gases causing global warming. The air conditioning cooling loads and the available solar power match well with each other along the day and seasons. According to the Internal Energy Agency (IEA), global energy demand will increase by 35% between 2010 and 2035 [4]. This increase is associated with world population and economic growth, especially in developing countries [5]. The other benefit of using the heat-driven cycle is the fact that the highest cooling demand is associated with the high solar energy in summer and that offers a good chance for the heat-driven cycle to match the cooling demand efficiently

Objectives

Results

Conclusion