Warren Rice

Freeze desalination using hydraulic refrigerant compressors

Abstract Freeze desalination of seawater using direct contact freezing and melting heat transfer has long been known to be very energy efficient. However, practical dificulties and developmental mishaps have blocked commercial success. The unsuitability of conventional refrigerant compressors for use in freeze desalination plants has been a major obstacle. The recent invention and development of the hydraulic refrigerant compressor now provides an excellent solution to the compressor problem, and the advantages are such as to make reconsideration of freeze desalination worthwhile. Herein suitable candidates are described for each of the principal system components including the hydraulic refrigerant compressors, and the characteristics of a resulting freeze desalination system are discussed.

Diffusion of impurities during epitaxy

The diffusion of impurities in both epitaxial layers and the substrate is considered. The differential equations and boundary conditions which describe the problems are derived and solutions are presented for both the idealizations of a semi-infinite substrate and the true thickness of the substrate. Several types of boundary conditions are considered. For the cases of diffusion of impurities with the substrate considered as semi-infinite, the results from digital computation are given in tabular and graphical form. The method of application of the information to the design and production of epitaxial structures is indicated. A comparison is made between the solutions accounting for diffusion during epitaxy and solutions for a rationalized situation in which diffusion is computed by simpler means, and the simpler method is shown to be unsatisfactory for epitaxial calculations.

Experimental results for a hydraulic refrigeration system using n-butane

Abstract The hydraulic refrigeration system (HRS) is a vapor-compression system that accomplishes the compression and condensation of the refrigerant in a unique manner, by entraining refrigerant vapor in a down-flowing stream of water and utilizing the pressure head of the water to compress and condense the refrigerant. A multi-stage HRS was designed, fabricated, and tested using n -butane as the refrigerant. In general, both the refrigeration rate and the coefficient of performance ( COP ) increased with a corresponding decrease in the compression fluid temperature of the third and final stage. The refrigeration rate and COP were also found to increase with a corresponding increase in evaporator temperature. The predictions of an enhanced model incorporating two-phase hydraulic losses show excellent agreement with the experimental data with a maximum error of ±20%. The results of the experimental investigation indicate that the HRS offers an attractive and feasible alternative to conventional vapor-compression systems, especially in applications where direct-contact heat exchange in the evaporator is desirable.

Characteristics of the hydraulic refrigeration system (HRS) using n-butane as the refrigerant

Abstract The HRS is a recent invention, the theoretical basis of which (using CFCs as the refrigerant) was discussed in an earlier paper. It is a vapor-compression refrigeration system, not an absorption system, and accomplishes the compression and condensation processes in a very unconventional way. The earlier work gave details of the analytical modeling and of computer-implemented calculations to determine component sizes and the expected performance of the system. Results were presented using several different CFC refrigerants. However, the HRS can safely use hydrocarbon refrigerants. Herein, the principles of the HRS are reviewed, and the results of calculations of component sizes and of distances and of the performance characteristics are presented for the use of n -butane as the refrigerant in an HRS. It is shown that the HRS components are about the same size as for the use of a CFC refrigerant and that the performance is somewhat better. The HRS achieves excellent performance mainly because the compression process is virtually isothermal. A description is given of a 10 ton HRS using n -butane and achieving an EER of approx. 15 with a 45°F evaporator temperature, with water circulating in the HRS at 100°F. It is shown that the HRS offers exceptional opportunities for modulation-type control that can further improve the values of the SEER.