The objective of this thesis is the design and realization of a higher efficiency air source heat pump. The improved pump???s operating cost must rival the cost of heating with natural gas, while incurring a minimal increase in the capital cost of the pump. A COP greater than 4 at ???15C ambient is needed to achieve this goal. During winter season testing a COP of 4.25 +/- 0.11 was observed. This tracks well with a predicted COP of 4.4 and also against a commercial system with a claimed COP between 2.1 and 3.0.

The report describes the project carried out for EasyServ, whose business is based on the monitoring and diagnosis of heat pumps. Their desire for the project was to develop a more efficient test system that makes it possible to easily simulate a heat pump behavior. The purpose of this was to enable more efficient tests with better accuracy for EasyServs product. This simplifies the quality assurance of the software for their product. The main problems the project were facing was how the test system should be designed and how the simulation of the heat pump's temperature sensors would be to mimic a heat pump. Another question mark was which communication interface was best suited for the test system. The method for constructing the test system was based on the use of the simulation technology Hardware-in-the-loop (HIL). The project was thus divided into subsystems Electronics Design and Programming. In Electronic design the decisions regarding the design were taken and the construction of the test system was made. The Programming subsystem deals with the development of the simulation program. The result was a test system consisting of a Raspberry Pi and a manufactured I/O board, where communication takes place through I²C. The I/O board has eight digital potentiometers which are used to simulate the heat pump’s temperature sensors. The simulation program developed in Raspberry Pi uses Python as programming language. The conclusion is that the project's test system provides a good basis for EasyServ to test their diagnostic tool in a simple way. A potential and desirable development that makes the test system even more useful for EasyServ would be to feedback the compressor signal.

Working fluids for thermal heat pump cycles have been studied. Methanol in conjunction with a mixture of inorganic bromides has been identified as being suitable for transforming heat from temperatures below zero centigrade. A computer programme was written in order to calculate the performance of such a combination, and its accuracy was verified by comparing its predictions with the actual performance of existing (commercial) heat pumps and chillers using combinations other than the above. Transport and other properties of the mixture have been measured, including vapour pressure, specific heat, viscosity, relative density, solubility, thermal conductivity, surface tension, heat of absorption, absorption coefficient, and hence mass diffusivity. An intermittent absorption heat pump was constructed and its performance measured. The tests demonstrated that it was capable of pumping heat from -10 °C up to 74 °C.

Thesis (Ph.D.)--University of Wyoming, 2007. / Title from PDF title page (viewed on June 17, 2009). Includes bibliographical references (p. 167-178).

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Environment has become a major concern for society, which awareness of the importance of an environmentally respectful development has been growing during the last decades. Economic reasons have encompassed this transition to a more planet friendly conception of human development. In fact, this transition has been parallel to the growing prices of fossil fuels, facing a clear perspective of a shortage on its availability, insufficient to cope with a growing demand in the near future. Within this context, the role of renewable energies in order to stop depending on fossil fuels and to reduce greenhouse gases emissions has become crucial.   Because of its climate, heating represents a major source of energy consumption in Sweden, accounting for almost 60% of the residential and services sector energy use. Maximizing the efficiency of heating systems and using renewable, environmentally friendly and economically sustainable sources of energy may have an enormous impact on both environment and economy.   In this thesis the use of district heating and ground heat pump for a multi-dwelling building is evaluated, both from the economic and environmental points of view. Both are recognized to be efficient heating systems, allowing important savings of other sources of energy, and respectful with the environment.   An installation combining both district heating and ground heat pump, for a multi-dwelling building in Gävle has been analyzed. Different scenarios have been considered, and results obtained show that when installing a ground heat pump, both economic savings and CO2 emissions reduction are obtained. Annual economic savings account for 16,8% when providing 60% of the thermal energy with the ground heat pump, and considering the investment associated to the recent installation of a new heat pump (in the case studied, boreholes were already drilled), the payback time is 7,4 years. CO2 emissions reduction for a normal year reaches 34%. However, if we look at the wider picture of electricity and heat production from a community (local, regional, national or even international) point of view, several considerations have to be taken into account, which are discussed in the report.

This thesis is an analysis of the simulated performance of two indirect heat pump assisted solar domestic hot water (i-HPASDHW) systems compared to two base systems: an electric domestic hot water (DHW) system and a traditional solar domestic hot water (SDHW) system. In this study, the four systems of interest were modeled in the TRNSYS software and simulated for a year in order to compare their performances. All of the systems had the same load profile and aimed to deliver domestic hot water at a constant temperature. This insured that each system delivered approximately the same amount of energy for the simulated period, thereby creating a common basis for comparison. The heat pump was introduced into the system configuration in an attempt to further improve the performance. Theoretically, the heat pump should send colder fluid to the collector which will extend the solar collection periods, both daily and seasonally when compared to the traditional SDHW system, as well as increase the efficiency of the collector. This will help to reduce the reliance on the electric auxiliary heaters and thus decrease the total electricity consumption. Both i-HPASDHW systems considered for this thesis collected more solar energy over the course of the simulated year compared to the base traditional SDHW system. They also consumed less electricity than the two base systems, which directly correlated to lower annual operating costs. It was concluded that the two i-HPASDHW systems analyzed in this study proved to be feasible configurations that performed more efficiently than the two base systems under the simulation conditions. However, it is important to understand that the results presented apply to the specific configurations. While the potential has been shown, prototypes must be built and tested with properly sized equipment for specific applications to get an accurate idea of the potential benefits. Also, equipment costs must be considered to determine payback periods for each system.

With the continued development of economy, the energy demand increases continually . The industry is interested in evaluating the technology of heat pump, with applications mostly for water heater. This thesis analyzes and compares the heating efficiency of electric heater, gas heater and heat pump heater . A fuzzy theory is employed to the developed heating algorithm to raise the efficiency of the heat pump heater and suppress the unnecessary heating at the high temperature. According to the experiment, the heat pump heater could reach 60% energy saving while gas heater could attain 23% in comparison with the electric heater under the same temperature, The system could work all year around and can provide users with water at a proper temperature. In the winter, COP of heat pump heater could reache 2.1~2.5 while in the summer around 2.61~2.95. The energy saving is obvious.