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The great need for cooling combined with Mexico's large availability of low enthalpy energy from non conventional energy resources such as geothermal energy, solar heat and waste heat from industrial processes, makes it very attractive to utilize these resources for cooling using heat driven absorption systems. The main purpose of the work described in this thesis is to obtain experimental and theoretical data on heat driven absorption cooling systems for the design of large scale systems. Thermodynamic design data have been theoretically derived for heat driven absorption heat pumps and heat transformers using the working pairs ammonia-water and ammonia-lithium nitrate for cooling, heating and simultaneous heating and cooling. The interaction between the operating parameters has been illustrated graphically. A computer model of the steady state thermodynamics of a heat driven ammonia-water system and an ammonia-lithium nitrate system has been developed. A comparison of both systems is made by assessing the effect of operating temperatures and heat exchanger effectiveness on the coefficient of performance for cooling and the heat transfer rates within the system. An experimental study on the performance of the absorber of an absorption cooling system operating on water-lithium bromide has been made. The experimental study of the adiabatic absorber was concerned with the determination of the effect of the evaporator heat load and the absorber reflux on the performance of the absorber. An experimental study of the operating characteristics of an experimental. absorption cooler using water-lithium bromide-lithium iodide and waterlithium bromide-zinc bromide as ternary systems has been made in order to achieve higher coefficients of performance and a lower risk of crystallization. Experimental studies with a small heat driven absorption cooling system operating on ammonia-water using a falling film generator were made. Low generator temperatures were achieved which will'enable the use of non focussing solar collectors as a heat source for the system. An ammonia-water absorption cooler operating on low enthalpy geothermal energy was installed and operated at two geothermal fields. The system was used to cool a small cold storage facility below freezing temperatures. The experimental and theoretical results on absorption cooling systems will provide a basis for the design of heat pump systems for industrial and commercial applications.

The performance of membrane heat exchangers for HVAC total energy recovery systems was evaluated through experimentation and detailed system modelling. The operating principle of the membrane heat exchanger (enthalpy heat exchanger) is based on passing ambient hot and humid supply air over one side of a porous membrane heat exchanger surface and cold and less humid room exhaust air on the other side of the transfer surface. Due to the gradient in temperature and vapour pressure, both heat and moisture are transferred across the membrane surface causing a decrease in temperature and humidity of the supply air before it enters the evaporator unit of the conventional air conditioner. Hence both sensible and latent energy are recovered. In this study, both experimental and numerical investigations were undertaken and mathematical models were developed to predict the performance of the latent heat recovery heat exchangers for use with conventional air conditioning systems. The membrane moisture transfer resistance was determined by a laboratory-scale permeability measurements. It was found that the membrane heat exchanger performance is significantly influenced by the heat exchanger flow profile and shape, heat and moisture transfer material characteristics, air velocity and air moisture content. Improvement of membrane heat exchanger performance requires an in depth study on flow, temperature and moisture distribution in the heat exchanger flow paths. Thus, a commercial CFD package FLUENT is used to model the membrane heat exchanger. However, software of this type cannot model moisture diffusion through the porous transfer boundary. Therefore, two user defined function codes have been introduced to model the moisture transfer in latent energy heat exchangers. The annual energy consumption of an air conditioner coupled with a membrane heat exchanger is also studied and compared with a conventional air conditioning cycle using the HPRate software. Energy analysis shows that in hot and humid climates where the latent load is high, an air conditioning system coupled with a membrane heat exchanger consumes less energy than a conventional air conditioning system. The membrane heat exchanger dehumidifies the air before it enters the air conditioning system, resulting in a decrease in energy consumption in comparison with conventional air conditioning system.

Thesis (Ph.D.)--University of Tulsa. / Bibliography: leaves 373-384.

Thesis (Ph.D.)--University of Rhode Island, 2005. / Adviser: Stanley Barnett. Includes bibliographical references.

Thesis (M.S.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 37-39). Also available on the World Wide Web.

Report (M.S.)--Virginia Polytechnic Institute and State University. M.S. 1993. / Vita. Abstract. Includes bibliographical references (leaves 53-54). Also available via the Internet.