Quantitative Analysis of Conventional Cooling Versus Absorption Cooling

By

TABLE OF CONTENTS

CHAPTER 1: INTRODUCTION3

CHAPTER 2: LITERATURE REVIEW6

Vapour Compression and Absorption Systems6

Vapour Compression System6

Vapour Absorption System6

Comparison7

Basic Refrigeration System and its components7

Compressor8

Classification Of Compressor8

Condenser10

Classification of condensers10

Evaporator12

Vapour Compression Refrigeration System13

Working14

Vapour Absorption Refrigeration System15

Working16

CHAPTER 3: METHODOLOGY18

Sizing cooling system components19

Investment cost20

Positive Externalities20

Cases and data21

REFERENCES23

APPENDIX26

CHAPTER 1: INTRODUCTION

The economics of five cooling systems - two conventional vapour compression systems and three solar (absorption and photovoltaic) cooling systems - are discussed and compared for different occupancies and capacities on the basis of respective life-cycle costs per unit of refrigeration output. The absorption system and the water- and air-cooled photovoltaic systems are assumed to receive equal amounts of conventional electricity. The study concludes that occupancy is a major factor in determining costs per ton-hour and cost per ton of installed capacity for all the cooling systems. At present, no solar cooling system can be considered a viable substitute for the conventional systems. Among all the solar systems considered, the absorption system is the most promising and the cost difference between that system and the conventional systems declines steadily as occupancy increases.

The major countries' climate is characterized by a long hot summer, which lasts from April until November, and by a short mild winter. A large share of electricity consumption in those countries is used for cooling of buildings during the summer and is sold at prices which are heavily subsidized. To conserve their oil resources and to prepare for the post-oil period, the Gulf countries are experimenting with new technologies (e.g. solar energy and wind energy) to develop alternative sources of energy. UK is a typical case of these countries. About 50% of annual electricity consumption is used in cooling of buildings' and is currently sold at 2 fils/kWh (KD 1.000 = 1000 fils = USS3.4). Solar technologies are being experimented in an effort to assess their potential as substitutes for conventional electricity in cooling of buildings.

In this paper the economics of solar cooling systems are discussed and compared with those of the conventional energy-based vapour compression cooling systems, air and water cooled, which are in common use in the country. It is argued that if the use of solar cooling systems is to become widespread, they would have to compete with the conventional systems, both technically and economically, on a priority basis, i.e. they would have to start by replacing the costlier conventional cooling systems. It is for this reason that the economics of conventional systems, air and water cooled, are analysed.

The paper deals with the economics of five cooling systems - two conventional systems, air-cooled vapour compression (cona) and water-cooled vapour compression (conw), and three solar-dependent cooling systems, solar absorption system (ab) and photovoltaic-utility air-cooled and water-cooled vapour compression systems, denoted by pvcea and pvcew respectively. It should be noted that even though the absorption system may receive all its thermal energy needs from solar sources it nevertheless requires electrical energy to drive its various pumps and fans. Vapour compression systems, however, depend solely on electricity, which means that ...