Independent metering poses a possibility to improve energy efficiency of throttlecontrolled hydraulic single-rod cylinder drives. This paper deals with energetic potentials gained through variable circuitry that come along with independent metering. A method to assess energetic potentials is described, based on load specific, optimal operating modes. As a means of yielding maximum energy efficiency for a wide range of applications, a smooth mode switching algorithm that minimizes losses and allows good motion tracking is proposed. The mode switching algorithm is validated in simulation and on a test stand.

This contribution presents an operating strategy for a novel valve structure for mobile machines’ working hydraulics which combines the flexibility and energetic benefits of individual metering with the functionality of common primary pressure compensation (IPC). The aim is to set up a system that uses a minimal amount of sensors and simple control algorithms. A control strategy theoretically described in /1/ is modified to facilitate the practical implementation on a mini excavator implement as a test rig. This test rig consists only of components that are currently available off-the-shelf to show that it is possible to develop an individual metering system under these economic restrictions. The novel is more energy efficient than common flow sharing systems but provides the same functionality. The control algorithm is experimentally evaluated in terms of functionality and energy consumption. Simulations show potential for further improvements.

Measures of individualization and integration offer a great potential for further development and optimization in hydraulic drive technology. Advantages are seen especially for energy efficiency and functionality. These potentials motivate current research activities for displacement controlled systems and for valve controlled structures. For the latter, the focus lies on strategies of independent metering. Furthermore, expected challenges for the future are discussed.

For delivery, dosing and pressure control of fluids in mobile and stationary applications electromagnetically operated piston pumps are an established solution. The volume per stroke is exactly defined by the geometry. Nevertheless cavitation, more likely with the new fuel blends containing a high proportion of ethanol /1/, deteriorates the dosing precision of the liquid portion. One important criterion of precise metering is the transport of the liquids through the reciprocating piston pump without transferring bubbles. Especially, pumping in the range of vapour pressure of gasoline fuels implies challenges for precision. The objective of this work is revealing potential sources of reduced cavitation by optimising the design. For doing so, optical investigations have been applied. In addition to this, cavitation can be diminished controlling the piston’s travel externally. The second important item covers pumping of degenerated fluids even without negative effects on the pump’s performance. Up to now, wide, inefficient gaps or high force surplus are necessary. A new helix-design /2/ has been investigated and built up in order to reduce the described effort. The effects coming with the helix allow a permanent rinsing of the stressed surfaces, leading to lubrication and lower temperature loads. The results are shown in simulation, fundamental tests and is validated in practical pump operation.

As intelligent hydraulic systems with embedded sensors become more ubiquitous, the real or perceived reliability challenge associated with sensors must be addressed to encourage their adoption. In this paper, a fault-tolerant control strategy for an intelligent independent metering valve that allows continued operation if a sensor fails is described. The twin-spool valve example utilizes position sensors to stabilize the spool positions and eliminate hysteresis, and pressure sensors to provide digital pressure compensation, electronic load sensing, and other features. An independent metering valve has redundancy provided by four sensors working together to control the flow into and out of a single actuator. Although two sensors are needed to control the flow through a spool, the controller can be reconfigured to ensure the flow is always controlled on the spool with both sensors working. To accomplish this, the concept of cross-port pressure control is introduced that uses the faulty side of the valve to maintain constant pressure on the non-faulty side. By maintaining a constant pressure, the flow in and out of the actuator are balanced. Experimental results on the boom of a backhoe demonstrate the operation of the fault tolerant control strategy.

Advanced Metering Infrastructure (AMI) is one of the most important components of smart grid (SG) which aggregates data from smart meters (SMs) and sends the collected data to the utility center (UC) to be analyzed and stored. In traditional centralized AMI architecture, there is one meter data management system to process all gathered information in the UC, therefore, by increasing the number of SMs and their data rates, this architecture is not scalable and able to satisfy SG requirements, e.g., delay and reliability. Since scalability is one of most important characteristics of AMI architecture in SG, we have investigated the scalability of different AMI architectures and proposed a scalable hybrid AMI architecture. We have introduced three performance metrics. Based on these metrics, we formulated each AMI architecture and used a genetic-based algorithm to minimize these metrics for the proposed architecture. We simulated different AMI architectures for five demographic regions and the results proved that our proposed AMI hybrid architecture has a better performance compared with centralized and decentralized AMI architectures and it has a good load and geographic scalability.

Non-residential users contribute to a significant portion of the total water delivered by water supplying agencies. However, a very limited number of studies have attempted to investigate the water use behavior of non-residential users. With the emergence of newer “smart” meters, water use now can be measured and recorded at a very high temporal frequency. Smart meters can help determine total water use, timing, and component end uses to better understand water use practices by non-residential users. Water end use disaggregation is the process of separating the water used by each fixture or process within a facility. This is useful because having a breakdown of the consumption of all end uses may encourage users to consume less water and gives them indications on how to do so. This project involved collecting and working with three different datasets with three different temporal scales (monthly billing data, 5-minute water use data, and 5-second water use data). We analyzed monthly billing data to solicit potential participating facilities for the study. For each participating facility, new smart devices were installed on their existing water meters, including an advanced water meter register and a pulse counting data logger. The newer registers logged and transmitted data to a web-accessible data portal at 5-minute intervals, while the pulse counters recorded water use at 5- second intervals. These devices enabled us to measure the timing and volume of different water uses (e.g., indoor versus outdoor versus industrial processes uses). In this project, we identified different water use events, average water used by each end use (from plumbing fixtures to industrial machinery), variability in end uses (faucets/toilets versus showers), variability in use by the type of user (manufacturing facilities versus assisted living homes), and the impact of the business type on the water use.

During the construction of the new 3 story, 25,000+ square foot police station, a decision was made to participate in the LEED program to ensure the building had low operating costs, reduced emissions, conserved water and overall energy. The design of the building includes a primary-secondary ground source heat pump (GSHP) loop, a Dedicated Outside Air System (DOAS) with Energy Recovery Ventilation (ERV) wheel, all controlled by CO2 monitoring through Demand Control Ventilation (DCV) to supply heat pumps located in each space; all monitored by a Building Automation System (BAS). The building’s future energy performance was predicted through an energy simulation model (ESM) software. Measurement and verification (M&V) was then performed on the building to determine its actual energy performance. Data was collected through the building’s electrical meters, the building automation system (BAS), and other techniques to determine discrepancies. Installed electrical submetering along with ESM results helped identify faults on a subcomponent level. This bottom up approach helped drive a successful retro-commissioning of the building systems reducing energy consumption. This thesis will detail a methodology for retro-commissioning of underperforming new-construction buildings. Optimization of the building’s systems will be facilitated through utilization of the M&V and ESM data. Discussed will be techniques and strategies to benchmark the building’s systems, providing utility from the retro-commissioning and M&V results, to determine the value of the ESM. Last will be to discuss and demonstrate the future benefits of utilizing this real-time data to help building operators reduce, manage, and sustain their energy consumption profiles.

The ability to measure flow in pipes often introduces expensive and difficult installations due to existing flow-meters being invasive. To solve this a non-invasive solution has been found by testing and evaluating different mechanical and electrical methods using ultrasonic piezo-crystals and time-of-flight calculations. The solution consists of an impedance matched circuit with a boosting circuit. Using ultrasound in an non-invasive way comes with a decreased accuracy which can be increased using various software methods. The results from tests at different water-flows shows that there is no significant statistical difference between the developed flow-meter and an existing mechanical one. It also shows that calibration has a major impact on the measured values. This hints at that with the right calibration of the ultrasonic flow-meter it should be possible to close the performance gap between the two flow-meters. / Möjligheten att mäta flöde i rör involverar ofta dyra och svåra installationer på grund av att existerande flödesmätare sitter i röret. För att lösa detta har en optimal icke-invasiv lösning hittats genom att testa och utvärdera olika mekaniska och elektriska metoder som använder piezo-kristaller och signalflygtid. Lösningen består av en impedansmatchningskrets och en boostkrets. Att använda ultraljud på ett icke invasisvt sätt kommer med en minskad precision som kan ökas genom att använda olika mjukvarulösningar. Resultaten från tester vid olika flödeshastigheter visar att det inte finns någon statistisk signifikans mellan den utvecklade flödesmätaren och en existerande mekanisk. Det visade också att kalibrering har en stor betydelse för mätvärderna. Det här visar på att man med rätt kalibrering borde kunna minska skillnaden i precision mellan de två mätarna.

Recent research at UCF into defining surrogate measures for identifying crash prone conditions on freeways has led to the introduction of several statistical models which can flag such conditions with a good degree of accuracy. Outputs from these models have the potential to be used as real-time safety measures on freeways. They may also act as the basis for the evaluation of several intervention strategies that might help in the mitigation of risk of crashes. Ramp Metering and Variable Speed Limits are two approaches which have the potential of becoming effective implementation strategies for improving the safety conditions on congested freeways. This research evaluates both these strategies in different configurations and attempts to quantify their effect on risk of crash on a 9-mile section of Interstate-4 in the Orlando metropolitan region. The section consists of 17 Loop Detector stations, 11 On-ramps and 10 off-ramps. PARAMICS micro-simulation is used as the tool for modeling the freeway section. The simulated network is calibrated and validated for 5 minute average flows and speeds using loop detector data. Feedback Ramp Metering algorithm, ALINEA, is used for controlling access from up to 7 on-ramps. Variable Speed Limits are implemented based on real-time speed conditions prevailing in the whole 9-mile section. Both these strategies are tested separately as well as collectively to determine the individual effects of all the parameters involved. The results have been used to formulate and recommend the best possible strategy for minimizing the risk of crashes on the corridor. The study concluded that Ramp Metering improves the conditions on the freeway in terms of safety by decreasing variance in speeds and decreasing average occupancy. A safety benefit index was developed for quantifying the reduction in crash risk and it indicated that an optimal implementation strategy might produce benefits of up to 55%. The condition on the freeway section improved with increase in the number of metered ramps. It was also observed that shorter signal cycles for metered ramps were more suitable for metering multiple ramps. Ramp Metering at multiple locations also decreased the segment wide travel-times by 5% and was even able to offset the delays incurred by drivers at the metered on-ramps. Variable Speed Limits (VSL) were individually not as effective as ramp metering but when implemented along with ramp metering, they were found to further improve the safety on the freeway section under consideration. By means of a detailed experimental design it was observed that the best strategy for introducing speed limit changes was to raise the speed limits downstream of the location of interest by 5 mph and not affecting the speed limits upstream. A coordinated strategy - involving simultaneous application of VSL and Ramp Metering - provided safety benefits of up to 56 % for the study section according to the safety benefit index. It also improved the average speeds on the network besides decreasing the overall network travel time by as much as 21%.