Thesis (M. S.)--Mechanical Engineering, Georgia Institute of Technology, 2008. / Committee Chair: Srinivas Garimella; Committee Member: David Sanborn; Committee Member: Sheldon Jeter.

Thesis (M.S.)--University of Wisconsin--Madison, 1982. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 131-132).

Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2007. / Includes bibliographical references (leaves 191-204). Also available in electronic version.

M.Ing. (Mechanical Engineering) / A reversible ground source heat pump, coupled to a municipality water reticulation system, is investigated as an alternative to conventional air source systems for space heating and cooling. The investigation was executed through the development of analytical models that were used for the design of a ground-coupled reversible heat pump and a conventional, also reversible air source system. The models were verified with experimental measurements. The results of the models and measurements indicate that ground source systems are a cost effective alternative.

M.Ing. / The refrigerant R22, which is currently used in hot water heat pumps, delivers a maximum hot water temperature of 60 to 65 °C. This temperature is adequate for domestic use, but low if compared to temperatures that can be delivered by fossil fuels and direct electric resistance systems. This limits the potential applications of hot water heat pumps. In this study two analytical design methodologies were developed that can be used to predict the performances of water-to-water heat pumps. The first design methodology is for a pure R22 heat pump and the second for a non-azeotropic refrigerant mixture of R22 and R142b. These design methodologies were used as tools together with three methods of comparison to determine the influence of a non-azeotropic refrigerant mixture (R22 mixed with R142b) on the performance of a hot water heat pump. It was found in certain cases that, depending on the concentrations, not only are increased hot water temperatures possible but also an improved heating capacity, an improvement in the coefficient of performance and a reduction in pressure ratio of the compressor.

An analytical investigation was attempted of a solar driven free-piston Stirling engine driving a second free-piston Stirling engine as a heat pump. A dynamic model and a thermodynamic model with free convection heat transfer were derived. The governing equations were programmed to obtain numerical solutions by computer. Graphs of piston displacements, volumes, pressures, mass cycles, and temperatures versus time are presented. Engine work output, operating frequencies, and efficiencies are calculated. Effects of parameter variations are presented. However, because proper phase angles could not be obtained for this model, the cooling performance of the system could not be evaluated. Limitations of the computer analysis are discussed and areas for possible further investigation are suggested

The residential heat pump is becoming more and more important as a means of heating and cooling homes. The American family is booming increasingly aware of year—round air conditioning in all its various aspects, not only for hosting and cooling the homo, but also for humidity control and air filtration. All those tasks may be accomplished with the installation of a single heat pump unit. Aside from the relatively new concept of cooling buildings during the summer, the heat pump has very distinct advantages when its use as a means of heating alone is considered. The heat pump uses electricity to heat. The individual can perceive immediate advantages in this aspect. The dirt and noxious gases of petroleum or coal combustion are eliminated. The fuel handling and combustion by-product removal equipment are no longer necessary. There is a significant reduction of fire hazard which should be reflected in lower fire insurance costs. The installation of a heat pump would be a distinct advantage architecturally because the heating unit no longer must be placed in a basement or large utility room adjacent to a chimney and fuel storage. In communities where smoke or smog conditions have become serious, extensive installation of electric heating apparatus would be most beneficial. Unless the consumer is willing to assign a monetary value to the afore-listed advantages of the heat pump, he will generally find that in areas where electricity costs over 1-1/2 cents per KWH, it is more expensive to operate than a conventional heating plant.(1O) This figure will of course vary with local fuel costs, heat loads, and heat pump coefficient of performance (COP). In recent years power companies have enthusiastically encouraged the widespread installation of electric heating apparatus, such as the heat pump, by attempting to make their operating costs competitive to other forms of heating. The reason for this encouragement may easily be detected by studying power consumption statistics. The influx of an increasing number of electrical appliances into the home has greatly increased the average power consumption in most areas. However this power consumption varies greatly with the time of day, being at a peak in the early evening, and at a relatively very low minimum in the early morning hours. The utility companies must install sufficient capacity to carry these peak loads, and therefore have machinery idle or operating below rated load and efficiency during the minimum consumption periods. To help offset this economically adverse condition, the power companies are in many areas willing to give rate discounts to consumers using electric heating, as the greatest capacity demands are placed on these units during the minimum power consumption hours. Owners of heat pumps may receive power rate discounts generally in one of two ways, either by a reduced cost per KWH over a certain number, or by the installation of a power meter in which time is integrated with the rate of flow of power, giving a separate or a numerically reduced reading during the off peak hours. The former method is in more widespread use today, however the latter method, although more involved and costly, seems to be more in line with power company objectives. The author has been commissioned as consultant to the architect to design a heat pump system for a proposed residence for Brig. General C. H. Shuey, U.S.H.C. (Ret.). This home is to be built on Sinnepuxant Bay, Maryland. The architect has specified heating is to be accomplished by means of a radiant floor panel. This requirement together with the proximity of a boundless supply of water to use as the heat pump sink and heat source, suggests the use of a water-to—water heat pump system. As a radiant floor panel cannot be used to cool, auxiliary air refrigerating apparatus will have to be installed. The objects of this thesis will be to compute the heating and cooling requirements for the building; to design the radiant floor panels and auxiliary cooling apparatus; and to design the water-to-water heat pump and its associated equipment. / Master of Science

All available information on heat pumps was read and the articles pertaining directly to design, operation, and the overall performance of air-to-air heat pumps were included in the Review of Literature. The advantages and disadvantages of the basic types of systems and their heat sources were explained. A few of the outstanding units as well as small commercial units were discussed, but the data published on these units were very limited as to design and operating values. One of the major problems encountered with air-to-air heat pumps is the defrosting of the outside coil. Several methods were outlined but the best solution for defrosting the coil would depend upon the conditions pertaining to each unit. Several suggestions were outlined where research is needed for the proper utilization of air as a heat source and sink. arter several trial and error solutions the system was designed to give a conditioned air temperature of 100 degrees F for an outside temperature of 30 degrees F and a heat de= Livery of 436.3 Btu/min. The assumed room temperature was 75 degrees F which gave a 25 degree differential across the inside coil, With an 18 degree differential across the outside coil a refrigerating effect of 338.0 Btu/min could be picked up from the outside air. These values appeared to give the best operating conditions, The tubing was sized accordingly and considerations were given to the fact that the vapor lines would be used for both cycles. The stands were constructed and the component parts of the system were mounted on their respected stands. The piping, duct, and electrical work were completed. ‘The design and construction of each of these phases was done with emphasis on clarity, simplicity, and ease in operation and maintenance. The valves numbered 1 through 12 are the control valves. The system is operated on the heating cycle with the even-numbered valves opened and the odd-numbered valves closed. All the control valves, except the expansion valves and their bypasses, are located on the control board. A dehydrator and oil separator were installed in the pining circuits. A two-wattmeter method of power measurement was installed on the unit. This method enables the operators to determine the power supplied to each motor and instantaneous power when the load on the unit is changing. Each of the motors is protected by fusible disconnect boxes. The procedure for starting, operating, and shut down was explained with emphasis on the factors that should be watched for safe and satisfactory operation. The calculations were based upon the conditions of the air, the heat picked up from the outside air, the work supplied to the motors, and the heat gained by the room air. / Master of Science

D. Tech. Engineering: Mechanical. / Discusses the main objective of the study is to carry out a theoretical and experimental study of a water-to-water CO2 heat pump system and improve its performance by optimizing its working parameters and conditions. The optimization process will be based on South African conditions.Specific objectives to meet the required goal are: 1. Carry out the installation and experimental analysis of a water to water CO2 heat pump system.2. Evaluate the reliability of the system using statistical means through regression analysis and create relationship models between the input and output parameters of the system.3. Execute a thermodynamic analysis of the selected system and evaluate the most important factors that affect its energy efficiency, then identify and evaluate possible system improvements and optimum operating conditions. 4. Compare available heat pump related kinematic and mathematical models and evaluate the best model to describe the operations in the system under local operating conditions. Suggest further improvements to the models and evaluate these too.5. Perform computer modelling and simulations to analyse the CO2 heat pump system,supplement the measurements from the test rig and compare the results.

Since the ancient years, human beings were using holes and caves to protect themselves from weather conditions making it the first known form of exploiting ground’s heat, known as Geothermal Energy. Nowadays, geothermal energy is mainly used for electricity production, space heating and cooling, Ground Coupled Heat Pump (GCHP) applications, and many other purposes depending on the morphology of the ground and its temperature. This study presents results of investigations into the evaluation of the thermal properties of the ground in Cyprus. The main objectives were i) to determine the thermal characteristics of the ground in Cyprus, ii) investigate how they affect the sizing and positioning of Ground Heat Exchangers (GHE) and iii) present the results for various ground depths, including a temperature map of the island, as a guide for engineers and specifiers of GCHPs. It was concluded that there is a potential for the efficient exploitation of the thermal properties of the ground in Cyprus for geothermal applications leading to significant savings in power and money as well. Six new boreholes were drilled and two existing ones were used for the investigation and determination of i) the temperature of the ground at various depths, ii) its thermal conductivity, iii) its specific heat and iv) its density. The thermal conductivity was determined by carrying out experiments using the line source method and was found to vary in the range between 1.35 and 2.1 W/mK. It was also observed that the thermal conductivity is strongly affected by the degree of saturation of the ground. The temperature of the undisturbed ground in the 8 borehole locations was recorded monthly for a period of 1 year. The investigations showed that the surface zone reaches a depth of 0.25 m and the shallow zone 7 to 8 m. The undisturbed ground temperature in the deep zone was measured to be in the range of 18.3 °C to 23.6 °C and is strongly dependent on the soil type. Since the ground temperature is a vital parameter in ground thermal applications, the temperature of the ground in locations that no information is available was predicted using Artificial Neural Networks and the temperature map of the island at depths of 20 m, 50 m and 100 m was generated. Data obtained at the location of each borehole were used for the training of the network. Data for the sizing of GHEs based on the ground properties of Cyprus were presented in an easily accessible form so that they can be used as a guide for preliminary system sizing calculations. With the aid of Computational Fluid Dynamics (CFD) software the capacity of the GHEs in each location and the optimum distance between them was estimated. Additionally, the long term temperature variation of the ground was investigated. For the first time since a limited study in the 1970’s, a research focusing on the determination and presentation of the thermal properties of the ground in Cyprus has been carried out. Additionally, the use of Artificial Neural Networks (ANNs) is an innovative approach for the prediction of data at locations where no information is available. The publication of this information not only contributes to knowledge locally but also internationally as it enables comparison with other countries with similar climatic conditions to be carried out.