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.

With increasing energy costs and competitive pressures, interest has increased in surveying installed pumps for potential energy savings. Field pump efficiency tests are required to assess pumping performance and help to identify improvement opportunities. This work concerns the on-site measurements of pulp-suspension pumping efficiency. This involves the measurement of pump head, flow rate and power consumption. Provided that consistent flow measurements are available, it is possible to reliably and non-invasively measure actual pump system efficiencies in pulp suspension flow, with a minimum process disturbance. As part of a most appropriate measurement-procedure study, four portable nonintrusive flow meters were evaluated on site for pulp suspension flow. The Fast Fourier Transform Doppler was found to be the most suitable for a pulp mill pump survey. Efficiency measurements were performed on six pump systems with motors between 100 and 700 HP. It is shown that as-installed pump efficiency can be used to help predict the degradation of the pump and also its effect on the pumping system’s operation. A system approach analysis was performed in each case, which can be effective in assessing system performance and finding potential enhancements. The use of variable speed drives allows the operating point to move along the system curve, requiring less energy to drive the pump. VSD of larger motors are expensive and their profitability compared to other modification alternatives should always be carefully checked by calculations based on accurate on site measurements and life cycle costs. Finally, in this survey of six pump systems, significant potential savings of around 30% of present power consumption were found.

With increasing energy costs and competitive pressures, interest has increased in surveying installed pumps for potential energy savings. Field pump efficiency tests are required to assess pumping performance and help to identify improvement opportunities. This work concerns the on-site measurements of pulp-suspension pumping efficiency. This involves the measurement of pump head, flow rate and power consumption. Provided that consistent flow measurements are available, it is possible to reliably and non-invasively measure actual pump system efficiencies in pulp suspension flow, with a minimum process disturbance. As part of a most appropriate measurement-procedure study, four portable nonintrusive flow meters were evaluated on site for pulp suspension flow. The Fast Fourier Transform Doppler was found to be the most suitable for a pulp mill pump survey. Efficiency measurements were performed on six pump systems with motors between 100 and 700 HP. It is shown that as-installed pump efficiency can be used to help predict the degradation of the pump and also its effect on the pumping system’s operation. A system approach analysis was performed in each case, which can be effective in assessing system performance and finding potential enhancements. The use of variable speed drives allows the operating point to move along the system curve, requiring less energy to drive the pump. VSD of larger motors are expensive and their profitability compared to other modification alternatives should always be carefully checked by calculations based on accurate on site measurements and life cycle costs. Finally, in this survey of six pump systems, significant potential savings of around 30% of present power consumption were found.

With increasing energy costs and competitive pressures, interest has increased in surveying installed pumps for potential energy savings. Field pump efficiency tests are required to assess pumping performance and help to identify improvement opportunities. This work concerns the on-site measurements of pulp-suspension pumping efficiency. This involves the measurement of pump head, flow rate and power consumption. Provided that consistent flow measurements are available, it is possible to reliably and non-invasively measure actual pump system efficiencies in pulp suspension flow, with a minimum process disturbance. As part of a most appropriate measurement-procedure study, four portable nonintrusive flow meters were evaluated on site for pulp suspension flow. The Fast Fourier Transform Doppler was found to be the most suitable for a pulp mill pump survey. Efficiency measurements were performed on six pump systems with motors between 100 and 700 HP. It is shown that as-installed pump efficiency can be used to help predict the degradation of the pump and also its effect on the pumping system’s operation. A system approach analysis was performed in each case, which can be effective in assessing system performance and finding potential enhancements. The use of variable speed drives allows the operating point to move along the system curve, requiring less energy to drive the pump. VSD of larger motors are expensive and their profitability compared to other modification alternatives should always be carefully checked by calculations based on accurate on site measurements and life cycle costs. Finally, in this survey of six pump systems, significant potential savings of around 30% of present power consumption were found. / Applied Science, Faculty of / Mechanical Engineering, Department of / Graduate

Most current designs for Left Ventricular Assist Devices (LVAD) are based on rotary pumps due to their small size and lack of valves. However, the majority of FDA approved LVADs are larger, positive displacement pumps. One reason for this may be because positive displacement pumps produce pulsatile flow, similar to that of the natural heart, while rotary pumps produce continuous flow. Continuous flow has been shown to support the circulation for short periods of time during open-heart surgery, but it has seen limited success with long-term support. It is thought that pulsatile flow provides many metabolic advantages to patients with high total peripheral resistance (TPR) and lower flowrates. This study focused on modifying a continuous flow multiple disk centrifugal pump (MDCP) into a pulsatile pump, to allow for the combined benefits of the pulsatility from positive displacement pumps and the small size and valveless design of rotary pumps. An efficiency study was carried out by evaluating the hydraulic work output and the power requirements of the pump. The pump was evaluated in both pulsatile and continuous flow modes. In continuous mode, the pump was able to maintain a flow of 5.5 L/min against a pressure head of 60mmHg at 1155rpm. Other LVADs have reported rotational speeds around 2400rpm for centrifugal and 10,000rpm for axial pumps to produce flows around 5 L/min. This indicates that the MDCP is capable of producing flowrates at lower rotational speeds than other LVADs, lessening the mechanical wear of the parts, thus potentially increasing the device's lifespan. In pulsatile mode, cardiac outputs of 5 L/min were achieved against a 55/27mmHg outlet pressure. Higher pressures were unattainable with our current testing apparatus, but the results from the pulsatile tests prove that the MDCP can be operated in a pulsatile fashion and produce normal flowrates at low pressures. The pump efficiency was lower than expected, around 0.7-9% in continuous mode and 3-18% in pulsatile mode, consuming 3.5-28W and 0.5-2.3W, respectively. Utilizing a smaller motor may produce higher efficiencies, since the power requirements will be less without decreasing the flowrates, but a further study should be conducted in order to verify this.

The aim of the diploma thesis is to design the pump impeller. The classical design of the impeller is made for one operating point, in which pump is assumed to operate most of the time. The aim of this diploma thesis is to design a pump, whose pump cover and pump drive discs are designed for each other operating point and then compare the results of both design methods.

As renewable energy production becomes more prevalent, the challenge of producing renewable dispatchable fuel for the transportation sector remains unresolved. One promising approach is to produce hydrogen from solar energy with a two step thermochemical cycle which utilizes an oxygen storage material (OSM) to split water through two reversible reactions. Due to the strong coupling between reactor design, operational parameters, and OSM properties, the direct comparison of two OSMs is not straightforward. In order to guide the designs of OSMs for two-step thermochemical hydrogen production, a methodology is developed to model the max performance possible for a two-step thermochemical cycle. The novel contribution of this model considers the strong coupling between reactor operation, OSM properties, and reactor performance. Next, a method for screening and evaluating new OSMs which utilizes thermogravimetric analysis (TGA) is proposed. With this data, the modeling method previously developed is applied to determine maximum reactor efficiency possible with new materials. This allows many materials to be evaluated quickly, and facilitates further characterization new OSMs. Additionally, by comparing the predicted maximum efficiency of a new material with the efficiency of current ones, this method facilitates the comparison of two different OSMs on equal footing.

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