Power-adaptive plunger pump as a part of reverse osmosis system

Uusiutuvien energianlähteiden hyödyntämisen haasteena on niiden tuottaman tehon vaihtelevuus verrattuna perinteisesti teollisuudessa käytettyihin fossiilisten polttoaineiden ja ydinvoiman tuottamaan tasaiseen ja ennalta tiedettyyn tehoon. Uusiutuvan energian käyttöönotto edellyttääkin siten uusien laitteiden suunnittelua, jotka mahdollistavat tuotetun tehon maksimaalisen hyödyntämisen, riippumatta tehon vaihtelevuudesta. Käänteisosmoosilaitoksessa myös laitteiden kuorma voi olla vaihtelevaa, jos suolanpoistoon käytettävien kalvoyksiköiden määrää muutetaan käytettävissä olevan syöttötehon perusteella. Vaihtelevaan tehoon ja kuormaan mukautuva pumppu voisi olla eräs ratkaisu mahdollisimman korkean hyödyn tuottamiseksi uusiutuvista energianlähteistä. Tämän diplomityön tavoitteena on kehittää vesihydraulinen korkeapainepumppu, jolla on erinomainen hyötysuhde ja joka kykenee mukautumaan tehonvaihteluihin. Diplomityössä suunniteltiin vesi-hydraulinen uppomäntäpumppu sekä simulointiin laskennallisesti sen toimintaa tasaisella sekä vaihtelevalla kuormalla. Nämä simulaatiot tehtiin tuuliturbiinikäyttöisestä käänteisosmoosilaitoksesta, jossa suunniteltu pumppu on kytketty mekaanisesti tuuliturbiiniin. Vertailujärjestelmänä pidettiin laitosta, jossa tuulisähkö ensin taltioidaan akkuihin ja sitten tavallisen pumpun pyörittävää sähkömoottoria käytetään talletetulla sähkövirralla. Työssä tutkittiin myös uppomäntäpumpun sopivuutta erilaisten uusiutuvan energian talteenottolaitteiden kanssa sekä perustellaan miksi käänteis-osmoosi soveltuu parhaiten suolaveden suodatukseen. Suunnitelmien perusteella on valmistettu adaptiivinen uppomäntäpumppu, jota tutkitaan jatkotutkimuksissa. Simuloinneista saatujen tulosten perusteella adaptiivisella pumpulla voitaisiin tuottaa 20 % enemmän puhdasta vettä verrattuna saman kokoluokan sähköisesti avustettuun järjestelmään kun pumppausjärjestelmää käytetään vaihtelevalla teholla. Lisäksi adaptiivista pumppua käyttämällä koko järjestelmän investointi- ja huoltokustannukset pienenevät, koska sähköisen järjestelmän laitteistoa ei tarvita.Renewable energy sources produce fluctuating power. In the industry, however, the processes are designed to work with constant power which the fossil fuels and nuclear energy produce. Accordingly, for increasing the use of renewable energy sources, new state-of-the-art machinery must be developed to utilize the generated fluctuating power more efficiently. Moreover, as in reverse osmosis, the load can also fluctuate if the number of desalinating membranes is changed proportionately to the available power. Design of a power-adaptive pump could re-solve the challenge of the fluctuating power and increase the usage of renewable energy sources. The goal of this master’s thesis was to develop a water hydraulic high-pressure plunger pump, which has excellent efficiency and can adapt to fluctuating power. In the master’s thesis, a water hydraulic plunger pump was designed and simulated with constant as well as variable load. The simulations were made using a wind turbine powered reverse osmosis facility, where the designed power-adaptive pump is mechanically attached to the wind turbine. A comparison system was one that first stores the electrical energy into batteries and then uses that electrical energy to drive a motor which drives a normal plunger pump. An aim of the thesis is to identify the possible renewable energy converters that the power-adaptive pump could be compatible with and powered by in a reverse osmosis system. Another aim is to demonstrate why reverse osmosis is the best desalination method. A plunger pump was manufactured according the design introduced in this thesis. The pump will be tested as follow-up research. According to the simulations, the power-adaptive plunger pump produces 20 % more desalinated water than the same size electrically aided system when the pumping system was driven with a fluctuating power source. Furthermore, by using a power-adaptive pump, the investment and maintenance costs are significantly lower because then the electrical support system is not needed

Comparison of Semi-autonomous Mobile Robot Control Strategies in Presence of Large Delay Fluctuation

We propose semi-autonomous control strategies to assist in the teleoperation of mobile robots under unstable communication conditions. A short-term autonomous control system is the assistance in the semi-autonomous control strategies, when the teleoperation is compromised. The short-term autonomous control comprises of lateral and longitudinal functions. The lateral control is based on an artificial potential field method where obstacles are repulsive, and a route is attractive. LiDAR-based artificial potential field methods are well studied. We present a novel artificial potential field method based on color and depth images. Benefit of a camera system compared to a LiDAR is that a camera detects color, is cheaper, and does not have moving parts. Moreover, utilization of active sensors is not desired in the particle accelerator environment. A set of experiments with a robot prototype are carried out to validate this system. The experiments are carried out in an environment which mimics the accelerator tunnel environment. The difficulty of the teleoperation is altered with obstacles. Fully manual and autonomous control are compared with the proposed semi-autonomous control strategies. The results show that the teleoperation is improved with autonomous, delay-dependent, and control-dependent assist compared to the fully manual control. Based on the operation time, control-dependent assist performed the best, reducing the time by 12% on the tunnel section with most obstacles. The presented system can be easily applied to common industrial robots operating e.g. in warehouses or factories due to hardware simplicity and light computational demand.Peer reviewe

Cost-Benefit Analysis of Electric Bus Fleet with Various Operation Intervals

Electric buses are particularly suitable for city and suburban routes due to zero local exhaust and noise emissions. The operation schedule interval defines the charging power, bus fleet size and total cost of ownership of a bus. We propose a novel cost-benefit method for the scheduling of an electric city bus fleet on a single route. Three different charging infrastructure scenarios were considered. In the first scenario, only one charging station was used. The second scenario considered two charging stations that were located at the same terminus. In the third scenario, two charging stations were located at opposite terminuses. The costs and utilization rates of the buses were analyzed with operation intervals up to 40 minutes. The first scenario with a single charging station had the lowest costs for the entire bus fleet system when the utilization rate was considered. Furthermore, the results show that certain schedule intervals are more cost-beneficial in terms of vehicle specific life-cycle costs than others. In the future, the proposed method is expanded to aid the design of bus network scheduling under energy demand uncertainty.Peer reviewe

Reducing the energy consumption of electric buses with design choices and predictive driving

Peer reviewe

Energy Uncertainty Analysis of Electric Buses

Uncertainty in operation factors, such as the weather and driving behavior, makes it difficult to accurately predict the energy consumption of electric buses. As the consumption varies, the dimensioning of the battery capacity and charging systems is challenging and requires a dedicated decision-making process. To investigate the impact of uncertainty, six electric buses were measured in three routes with an Internet of Things (IoT) system from February 2016 to December 2017 in southern Finland in real operation conditions. The measurement results were thoroughly analyzed and the operation factors that caused variation in the energy consumption and internal resistance of the battery were studied in detail. The average energy consumption was 0.78 kWh/km and the consumption varied by more than 1 kWh/km between trips. Furthermore, consumption was 15% lower on a suburban route than on city routes. The energy consumption was mostly influenced by the ambient temperature, driving behavior, and route characteristics. The internal resistance varied mainly as a result of changes in the battery temperature and charging current. The energy consumption was predicted with above 75% accuracy with a linear model. The operation factors were correlated and a novel second-order normalization method was introduced to improve the interpretation of the results. The presented models and analyses can be integrated to powertrain and charging system design, as well as schedule planning.Peer reviewe

Brake Light Detection Algorithm for Predictive Braking

There has recently been a rapid increase in the number of partially automated systems in passenger vehicles. This has necessitated a greater focus on the effect the systems have on the comfort and trust of passengers. One significant issue is the delayed detection of stationary or harshly braking vehicles. This paper proposes a novel brake light detection algorithm in order to improve ride comfort. The system uses a camera and YOLOv3 object detector to detect the bounding boxes of the vehicles ahead of the ego vehicle. The bounding boxes are preprocessed with L*a*b colorspace thresholding. Thereafter, the bounding boxes are resized to a 30 × 30 pixel resolution and fed into a random forest algorithm. The novel detection system was evaluated using a dataset collected in the Helsinki metropolitan area in varying conditions. Carried out experiments revealed that the new algorithm reaches a high accuracy of 81.8%. For comparison, using the random forest algorithm alone produced an accuracy of 73.4%, thus proving the value of the preprocessing stage. Furthermore, a range test was conducted. It was found that with a suitable camera, the algorithm can reliably detect lit brake lights even up to a distance of 150 m

Brake Light Detection Algorithm for Predictive Braking

There has recently been a rapid increase in the number of partially automated systems in passenger vehicles. This has necessitated a greater focus on the effect the systems have on the comfort and trust of passengers. One significant issue is the delayed detection of stationary or harshly braking vehicles. This paper proposes a novel brake light detection algorithm in order to improve ride comfort. The system uses a camera and YOLOv3 object detector to detect the bounding boxes of the vehicles ahead of the ego vehicle. The bounding boxes are preprocessed with L*a*b colorspace thresholding. Thereafter, the bounding boxes are resized to a 30 × 30 pixel resolution and fed into a random forest algorithm. The novel detection system was evaluated using a dataset collected in the Helsinki metropolitan area in varying conditions. Carried out experiments revealed that the new algorithm reaches a high accuracy of 81.8%. For comparison, using the random forest algorithm alone produced an accuracy of 73.4%, thus proving the value of the preprocessing stage. Furthermore, a range test was conducted. It was found that with a suitable camera, the algorithm can reliably detect lit brake lights even up to a distance of 150 m

Näytteenoton vertailukoe 14/2012. Maaperän haihtuvat öljyhiilivedyt

Näytteenottokäytännöt vaikuttavat tuloksen luotettavuuteen ja ovat siksi tärkeä osa maaperän pilaantuneisuuden ja puhdistustarpeen arviointia. Tämän vertailun tavoitteena oli selvittää, kuinka paljon haihtuvien öljyhiilivetyjen analyysitulokset (VOC) ovat riippuvaisia näytteenoton käytännöistä sekä, mitkä ovat tärkeimmät haihtuvien orgaanisten yhdisteiden näytteenotossa huomioitavat asiat. Vertailussa arvioitiin myös kenttämittarien (PID) käyttöä ja niiden tulosten luotettavuutta. Vertailu toteutettiin haihtuvilla öljyhiilivedyillä pilaantuneessa kohteessa, jossa vertailuun osallistujat suorittivat kenttänäytteenoton omalla vuorollaan. Osallistujien kenttämittarituloksia verrattiin referenssimittarin tuloksiin sekä osallistujien keräämät maanäytteet toimitettiin analysoitavaksi samaan laboratorioon. Vertailukokeeseen osallistui kahdeksan osallistujaa ja heidän toimintaa kentällä arvioitiin sekä annettiin suosituksia näytteenoton laadun parantamiseksi. Vaikka osallistujien kenttätoiminta pääosin oli hyvä, tulisi edelleen kiinnittää enemmän huomiota haihtuvien yhdisteiden haihtumisen ehkäisemiseen näytteenoton ja käsittelyn yhteydessä sekä työsuojelussa. Henkilösuojaimiksi tarkoitettuja kaasuhälyttimiä ei suositella käytettäväksi kenttämittarina maanäytteiden haihtuvien orgaanisten yhdisteiden pitoisuuden määrittämisessä. Vertailun tuloksien perusteella ei saatu selvää näyttöä siitä, että haihtuvien orgaanisten yhdisteiden näytteiden kestävöinti kentällä verrattuna näytteiden kestävöintiin laboratoriossa vaikuttaisi näytepitoisuuksiin. Haihtuvien yhdisteiden saannoissa ei myöskään havaittu näytteenottimesta johtuvia systemaattisia eroja

Prolongation of Battery Lifetime for Electric Buses through Flywheel Integration

Electrification of transportation is an effective way to tackle climate change. Public transportation, such as electric buses, operate on predetermined routes and offer quiet operation, zero local emissions and high energy efficiency. However, the batteries of these buses are expensive and wear out in use. The battery ageing is expedited by fast charging and power spikes during operation. The contribution of this paper is the reduction of the power spikes and thus a prolonged battery lifetime. A novel hybrid energy storage system for electric buses is proposed by introducing a flywheel in addition to the existing battery. A simulation model of the hybrid energy storage system is presented, including a battery ageing model to measure the battery lifetime. The bus was simulated during its daily driving operation on different routes with different energy management strategies and flywheel configurations. These different flywheels as well as the driving cycle had a significant impact on the battery life increase. The proposed hybrid battery/flywheel storage system resulted in a battery lifetime increase of 20% on average