Model predictive approach for the demand side management of S-market Tuira

Abstract. The decrease of the ecological footprint is crucial for the continuation of modern lifestyle as it is in the future. Decarbonization of the power grid is a major step towards this goal. The renewable resources, such as solar and wind, are becoming increasingly important methods of carbon free energy production. However, their integration to the power grid faces limitations due to their inherent seasonal- and circadian rhythms. Thus, the investment into carbon free energy production is only the first part of the solution, because the intermittent nature results in curtailment phenomena, where increased renewable power generation capacity does not result in increase in renewable penetration in the power grid. To get a completely decarbonized power grid, further technical solutions are needed that enable the renewable penetration into the power grid to rise to 100 %. The power grid has been using top-down architecture, where the aggregator side decides the amount of power generation done by the power plants since its introduction in the beginning of 20th century. In this model, the renewable energy is a disturbance, where power generation side must accommodate to the energy demand drop that the renewable power generation causes. To fix the problem, we also must redesign the power grid infrastructure in a way that high portion of renewable energy does not endanger the power grid stability and controllability. An easier way to manage renewables is by building smart micro-grids, which is an individual power grid with two-way power transfer capabilities. This results to easier decision-making on the grid aggregator side. All the micro-grids that are connected to the main power grid can be instructed how to accommodate their energy production and management to benefit the grid stability of main power grid, and to further improve the estimation of power generation demand of conventional power plants. Furthermore, we must develop tools that the microgrids can utilize to balance power demand across all power grid conditions dictated by the intermittent nature of power demand and renewable energy generation. Beyond the micro-grid introduction, the renewable energy proliferation faces limitations because of the intermittent nature of the renewable energy generation. For example, increasing the capacity of solar power generation will not work to replace conventional power generation after a point if we can only utilize the generated power during daytime. The solution here is to shift the consumption from daytime to night-time. To do this, we need to consider energy storage solutions. This thesis explores the possibility of utilizing cooling as part of power grid management using advanced process control methods in conjunction with an Internet-of-Things approach. More specifically, I investigate the idea of using refrigeration systems as one-way energy sinks that can be used to time-shift the consumption of electricity by storing at peak renewable power generation periods. The target system of the work is the steam-compression-cooling cycle of S-Market Tuira in Oulu, which has a carbon dioxide circulation. In his 2016 Master’s thesis dissertation, Jarno Johannes Tenhomaa has introduced a dynamic linear time variant state model that reflects the dynamics of the cycle, thus telling about the thermal inertia of the cooled products and thus the electricity demand of the cycle. In this work, a Model Predictive Controller is derived using a dynamic model of refrigeration systems, whose function is to control the air temperatures of the store’s refrigerators and freezers, which in turn are followed by the temperatures of the refrigerated products. The MPC control calculates the optimal control trajectory for the cooling system actuator, with which the temperature of the refrigeration system deviates from the set-point temperature as little as possible during the selected prediction horizon. Additionally, the different set-point temperature selection strategies are benchmarked in comparison to each other. The spot-price -based control changes the temperature set-point temperatures of the coolers and freezers according to Nord pool spot price data. The renewable portion data -based control strategies are based on power production data for the power grid in Finland provided by organization Energiateollisuus. For the purposes of testing the MPC controller and control strategy benchmarking, I have built a real-time interactive simulator in Matlab -program to illustrate the function and dynamics of the refrigeration systems of the supermarket.Malli-ennustava lähtökohta energia tarpeen hallintaan Tuiran S-Marketille. Tiivistelmä. Ekologisen jalanjäljen laskeminen on ratkaisevaa modernin elämäntavan jatkamisen ylläpitämiseksi. Hiilipohjaisista polttoaineista luopuminen sähköverkon ylläpitämiseksi on merkittävä askel kohti tätä tavoitetta. Uusiutuvista lähteistä, kuten aurinko- ja tuulivoimasta, on tulossa yhä tärkeämpiä menetelmiä hiilivapaassa energiantuotannossa. Niiden integroimisessa sähköverkkoon on kuitenkin rajoituksia johtuen niiden tyypillisistä vuodenaika- ja vuorokausirytmiriippuvaissuksista. Siten investointi hiilettömään energiantuotantoon on vasta ensimmäinen osa ratkaisua, koska niiden ajoittainen luonne johtaa pullonkaulailmiöön, joissa uusiutuvan sähköntuotantokapasiteetin kasvu ei enää lisää uusiutuvan energian sitoutumista sähköverkkoon. Täysin hiilettömän sähköverkon aikaan saamiseksi tarvitaan lisää teknisiä ratkaisuja, joiden avulla uusiutuvien energialähteiden tunkeutuminen sähköverkkoon voisi nousta jopa 100 prosenttiin. Sähköverkossa on jo 1900-luvun alusta asti käytetty ylhäältä alas -arkkitehtuuria, jossa aggregaattipuoli päättää voimalaitosten tuottaman sähkön määrän. Tässä mallissa uusiutuvan energian tuotanto on ’häiriötekijä’, johon sähköntuotantopuolen on sopeuduttava olemalla valmis laskemaan energiantuotanto voimalaitoksilla. Ongelman korjaamiseksi meidän tulee uudelleen suunnitella sähköverkkoinfrastruktuuri siten että uusiutuvan energian tuotanto ei vaaranna sähköverkon vakautta ja hallittavuutta. Helpompi tapa hallita uusiutuvan energian tuotantoa on rakentaa älykkäitä mikroverkkoja, jotka ovat pieniä autonomisia sähköverkkoja, joilla on kaksisuuntaiset virransiirtomahdollisuudet. Tämä helpottaa sähköverkon operaattoreiden päätöksentekoa. Kaikkia pääverkkoon kytkettyjä mikroverkkoja voidaan ohjeistaa siten että niiden energiantuotanto ja energian kulutus edistää pääverkon vakautta ja varmistaa, että voimalaitosten sähköntuotantotarpeisiin ei synny liian nopeita muutoksia. Mikroverkkojen käyttöönoton lisäksi on kehitettävä työkaluja, joita mikroverkot voivat käyttää tasapainottamaan sähkön kysyntää, jotta sähköverkko kykenee selviytymään kaikista olosuhteista, joita voi seurata uusiutuvan energian tuotannon ajoittaisesta luonteesta. Esimerkiksi aurinkoenergian tuotantokapasiteetin lisääminen ei toimi korvaamaan perinteistä sähköntuotantoa tietyn pisteen jälkeen, jos voimme käyttää aurinkoenergialla tuotettua sähköä vain päivällä. Ratkaisu tässä on siirtää kulutus päivältä yöaikaan. Tätä varten meidän on kehitettävä energian varastointiratkaisuja. Tässä opinnäytetyössä tutkitaan mahdollisuutta hyödyntää jäähdytystä osana sähköverkon hallintaa käyttämällä kehittyneitä prosessin ohjausmenetelmiä yhdessä Internet-of-Things-lähestymistavan kanssa. Erityisesti tutkin ajatusta käyttää jäähdytysjärjestelmiä yksisuuntaisina energianieluina, joilla voidaan ajoittaa sähkökulutus uudelleen ajanjaksoihin, jolloin uusiutuvan energian tuotanto on huipussaan. Työn kohde on Oulussa sijaitsevan S-Market Tuiran höyry-puristusjäähdytyskierto, jonka kieroaineena toimii hiilidioksidi. Jarno Johannes Tenhomaa on johdattanut matemaattisen mallin vuoden 2016 diplomityössään dynaamisen lineaarisen aikainvariantin tilamallin, joka kuvastaa kierron dynamiikkaa siten kertoen jäähdytettyjen tuotteiden termisestä inertiasta ja sitä kautta kierron sähköntarpeesta. Tässä työssä johdetaan malliennakoiva säädin (Model Predictive Controller) jäähdytysjärjestelmien dynaamista mallia hyödyntäen, jonka tehtävä on ohjata myymälän jääkaappien ja pakastimien ilman lämpötiloja, joita vuorostaan jäähdytettyjen tuotteiden lämpötilat seuraavat. MPC-säätö laskee jäähdytysjärjestelmän toimilaitteelle optimaalisen ohjauksen, jolla jäähdytysjärjestelmän lämpötila poikkeaa asetusarvosta mahdollisimman vähän valitun ennustushorisontin aikana. Lisäksi pyrin kehittämään ohjausstrategioita, jotka manipuloivat jäähdytysjärjestelmien virrankulutusta säätämällä vuorostaan malliennustavan säätimen asetusarvolämpötilaa. Näiden ohjausstrategioiden tavoite on varastoida joko halpaa ja / tai hiilineutraalia energiaa energianieluihin. Varastoitu energia voidaan myöhemmin hyödyntää aikoina, jolloin sähköverkon energia on kalliimpaa ja / tai tulee vähemmän hiilineutraaleista lähteistä. Energian Spot-markkinahintaan perustuva asetusarvon valintastrategia valitsee jääkaappien ja pakastimien asetusarvolämpötiloja Nord Pool AS:n Spot-hintatietojen mukaan. Sähköverkon uusiutuvan energian osuuteen pohjautuva asetusarvolämpötilan valintastrategia perustuu Energiateollisuus -etujärjestön julkaisemaan Suomen sähköverkon sähköntuotantotietoihin. Malliennustavan säätimen ja ohjausstrategioiden vertailuanalyysin tekemiseksi olen rakentanut reaaliaikaisen interaktiivisen simulaattorin Matlab-ohjelmaan, jolla pystyy havainnollistamaan supermarketin jäähdytysjärjestelmien toimintaa ja prosessin dynamiikkaa

Minimally-destructive detection of magnetically-trapped atoms using frequency-synthesised light

We present a technique for atomic density measurements by the off-resonant phase-shift induced on a two-frequency, coherently-synthesised light beam. We have used this scheme to measure the column density of a magnetically trapped atom cloud and to monitor oscillations of the cloud in real time by making over a hundred non-destructive local density measurments. For measurements using pulses of 10,000-100,000 photons lasting ~10 microsecond, the precision is limited by statistics of the photons and the photodiode avalanche. We explore the relationship between measurement precision and the unwanted loss of atoms from the trap and introduce a figure of merit that characterises it. This method can be used to probe the density of a BEC with minimal disturbance of its phase.Comment: Submitted to New Journal of Physic

Wearable device to assist independent living.

Older people increasingly want to remain living independently in their own homes. The aim of the ENABLE project is to develop a wearable device that can be used both within and outside of the home to support older people in their daily lives and which can monitor their health status, detect potential problems, provide activity reminders and offer communication and alarm services. In order to determine the specifications and functionality required for development of the device user surveys and focus groups were undertaken and use case analysis and scenario modeling carried out. The project has resulted in the development of a wrist worn device and mobile phone combination that can support and assist older and vulnerable wearers with a range of activities and services both inside and outside of their homes. The device is currently undergoing pilot trials in five European countries. The aim of this paper is to describe the ENABLE device, its features and services, and the infrastructure within which it operates

Tapered-amplified AR-coated laser diodes for Potassium and Rubidium atomic-physics experiments

We present a system of room-temperature extended-cavity grating-diode lasers (ECDL) for production of light in the range 760-790nm. The extension of the tuning range towards the blue is permitted by the weak feedback in the cavity: the diodes are anti-reflection coated, and the grating has just 10% reflectance. The light is then amplified using semiconductor tapered amplifiers to give more than 400mW of power. The outputs are shown to be suitable for atomic physics experiments with potassium (767nm), rubidium (780nm) or both, of particular relevance to doubly-degenerate boson-fermion mixtures

Anomalous radio emission from dust in the Helix

A byproduct of experiments designed to map the CMB is the recent detection of a new component of foreground Galactic emission. The anomalous foreground at ~ 10--30 GHz, unexplained by traditional emission mechanisms, correlates with 100um dust emission. We report that in the Helix the emission at 31 GHz and 100um are well correlated, and exhibit similar features on sky images, which are absent in H\beta. Upper limits on the 250 GHz continuum emission in the Helix rule out cold grains as candidates for the 31 GHz emission, and provide spectroscopic evidence for an excess at 31 GHz over bremsstrahlung. We estimate that the 100um-correlated radio emission, presumably due to dust, accounts for at least 20% of the 31 GHz emission in the Helix. This result strengthens previous tentative interpretations of diffuse ISM spectra involving a new dust emission mechanism at radio frequencies. Very small grains have not been detected in the Helix, which hampers interpreting the new component in terms of spinning dust. The observed iron depletion in the Helix favors considering the identity of this new component to be magnetic dipole emission from hot ferromagnetic grains. The reduced level of free-free continuum we report also implies an electronic temperature of Te=4600\pm1200K for the free-free emitting material, which is significantly lower than the temperature of 9500\pm500K inferred from collisionally-excited lines (abridged).Comment: Accepted for publication in Ap

ALMA OBSERVATIONS OF THE COLDEST PLACE IN THE UNIVERSE: THE BOOMERANG NEBULA

The Boomerang Nebula is the coldest known object in the universe, and an extreme member of the class of pre-planetary nebulae, objects which represent a short-lived transitional phase between the asymptotic giant branch and planetary nebula evolutionary stages. Previous single-dish CO (J = 1-0) observations (with a 45 '' beam) showed that the high-speed outflow in this object has cooled to a temperature significantly below the temperature of the cosmic background radiation. Here we report the first observations of the Boomerang Nebula with ALMA in the CO J = 2-1 and J = 1-0 lines to resolve the structure of this ultra-cold nebula. We find a central hourglass-shaped nebula surrounded by a patchy, but roughly round, cold high-velocity outflow. We compare the ALMA data with visible-light images obtained with the Hubble Space Telescope and confirm that the limb-brightened bipolar lobes seen in these data represent hollow cavities with dense walls of molecular gas and dust producing both the molecular-emission-line and scattered-light structures seen at millimeter and visible wavelengths. The large diffuse biconical shape of the nebula seen in the visible wavelength range is likely due to preferential illumination of the cold, high-velocity outflow. We find a compact source of millimeter-wave continuum in the nebular waist-these data, together with sensitive upper limits on the radio continuum using observations with ATCA, indicate the presence of a substantial mass of very large (millimeter-sized) grains in the waist of the nebula. Another unanticipated result is the detection of CO emission regions beyond the ultra-cold region which indicate the re-warming of the cold gas, most likely due to photoelectric grain heating

On the difference between type E and A OH/IR stars

The observed SEDs of a sample of 60 OH/IR stars are fitted using a radiative transfer model of a dusty envelope. Among the whole sample, 21 stars have reliable phase-lag distances while the others have less accurate distances. L*-P,Mlr-P and Mlr-L* relations have been plotted for these stars. It is found that type E (with emission feature at 10um and type A (with absorption feature at 10um) OH/IR stars have different L*-P and Mlr-L* relations while both of them follow a single Mlr-P relation. The type E stars are proven to be located in the area without large scale dense interstellar medium while the type A stars are located probably in dense interstellar medium. It is argued here that this may indicate the two types of OH/IR stars have different chemical composition or zero age main sequence mass and so evolve in different ways. This conclusion has reinforced the argument by Chen et al.(2001) who reached a similar conclusion from the galactic distribution of about 1000 OH/IR stars with the IRAS low-resolution spectra (LRS).Comment: 6 pages, 9 figures, 2 table

RESPOND – A patient-centred program to prevent secondary falls in older people presenting to the emergency department with a fall: Protocol for a multi-centre randomised controlled trial

Introduction: Participation in falls prevention activities by older people following presentation to the Emergency Department (ED) with a fall is suboptimal. This randomised controlled trial (RCT) will test the RESPOND program which is designed to improve older persons’ participation in falls prevention activities through delivery of patient-centred education and behaviour change strategies. Design and setting: An RCT at two tertiary referral EDs in Melbourne and Perth, Australia. Participants: Five-hundred and twenty eight community-dwelling people aged 60-90 years presenting to the ED with a fall and discharged home will be recruited. People who: require an interpreter or hands-on assistance to walk; live in residential aged care or >50 kilometres from the trial hospital; have terminal illness, cognitive impairment, documented aggressive behaviour or history of psychosis; are receiving palliative care; or are unable to use a telephone will be excluded. Methods: Participants will be randomly allocated to the RESPOND intervention or standard care control group. RESPOND incorporates: (1) home-based risk factor assessment; (2) education, coaching, goal setting, and follow-up telephone support for management of one or more of four risk factors with evidence of effective intervention; and (3) healthcare provider communication and community linkage delivered over six months. Primary outcomes are falls and fall injuries per-person-year. Discussion: RESPOND builds on prior falls prevention learnings and aims to help individuals make guided decisions about how they will manage their falls risk. Patient-centred models have been successfully trialled in chronic and cardiovascular disease however evidence to support this approach in falls prevention is limited. Trial registration. The protocol for this study is registered with the Australian New Zealand Clinical Trials Registry (ACTRN12614000336684)

Shape coexistence at the proton drip-line: First identification of excited states in 180Pb

Excited states in the extremely neutron-deficient nucleus, 180Pb, have been identified for the first time using the JUROGAM II array in conjunction with the RITU recoil separator at the Accelerator Laboratory of the University of Jyvaskyla. This study lies at the limit of what is presently achievable with in-beam spectroscopy, with an estimated cross-section of only 10 nb for the 92Mo(90Zr,2n)180Pb reaction. A continuation of the trend observed in 182Pb and 184Pb is seen, where the prolate minimum continues to rise beyond the N=104 mid-shell with respect to the spherical ground state. Beyond mean-field calculations are in reasonable correspondence with the trends deduced from experiment.Comment: 5 pages, 4 figures, submitted to Phys.Rev.