الفهرس 
Introduction.Only 14 pages are availabe for public view
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Abstract
The current research aimed at using the Stirling refrigerator/heat pump for domestic uses. Hence, it was chosen to use this new advanced technology for water cooling/ heating since the water cooler/ heater appliance, the water dispenser unit, became one of the most important appliances nowadays due to the need for clean water of suitable temperatures for the daily domestic usage. The conventional water cooler/heater units use a traditional vapor compression cycle for water cooling; whereas they use ordinary electric heaters for water heating. The conventional water dispenser model already seems to be an energy destructive device due to the usage of the electric heater for heating. Also, the conventional apparatus has a high potential for the environmental pollution and green house due to the usage of the harmful refrigerants.
On the other hand, the Stirling refrigerator/heat pump has several advantages including using eco-friendly working fluids such as air, quiet operation, compact size, fast cool-down and high coefficient of performance, theoretically equals to Carnot COP. Furthermore, the cycle was used as cooler and heater at the same time. The heat absorbed by the Stirling cycle was adopted to cool-down the water (in the cooling side) whereas; the heat rejected from the machine was recovered again for heating-up the water (in the heating side) and hence, saving more energy.
Initially, a design for the Stirling water dispenser was proposed according to the dimensions and capacities of the conventional machines. It was suggested to use an alpha type (V-arrangement) to benefit the advantage of using the commercially available V-type reciprocating air compressor. Using the V-type reciprocating air compressor, the main structure of the Stirling machine was built.
A theoretical model was developed according to the Schmidt analysis taking into consideration the effects of the dead volume, heat transfer, pressure loss and the imperfect regeneration. A computer program in the form of spreadsheet was prepared and the different parameters were calculated at each crank angle. The performance of the machine was estimated according to the initial operating conditions and the dimensions of the different machine components. Furthermore, an optimization technique was used to demonstrate the effect of each parameter on the machine performance and finding the optimum machine dimensions and operating conditions.
Subsequently, the Stirling water dispenser was manufactured according to the dimensions of the theoretical analysis. The V-type reciprocating air compressor was prepared for the usage in the Stirling machine. By uncovering the heads of the compressor, there are two pistons; one will be used in the cooling side, while the other will be used in the heating side. The two pistons are connected through two connecting rods to the crankshaft, the drive mechanism. The crankshaft maintains a constant phase shift between the compression and the expansion pistons of 90º. The drive mechanism is contained in a casing and rotates through a lubricating oil to decrease friction. Also, the cold, hot and regenerator heat exchangers were manufactured according to the optimized dimensions. The different components of the machine were assembled together and the measuring devices were properly fitted in the measuring locations in the machine. Finally, the machine was coupled to the electrical motor through a pulley and V-belt.
The machine was run and tested at different operating conditions. The specified cold and hot water temperatures were achieved at different operating conditions for the specified cold and hot water capacities. Moreover, the machine was run and tested at no cooling load conditions and nearly constant hot side temperature. At the no cooling load conditions, a frost was formed on the tubes of the cold heat exchanger and the temperature reached about -11 ºC.
The machine successfully approved its capabilities in cooling and heating. The machine could be practically used to replace the conventional water dispensers. Furthermore, the Stirling refrigerator/heat pump machine could be used for different industrial cooling, freezing and heating applications.