Huoneistokohtaisen ilmanvaihtokoneen lämmöntalteenoton ja äänenvaimentimien kehitys

Tämän työn tavoitteena oli selvittää erään ilmanvaihtokoneen lämmöntalteenottokennon vuosihyötysuhde japohtia voitaisiinko ilmastointikoneen energiatehokkuutta parantaa käyttämällä nykyisen ristivirtalämmönsiirtimen tilalla vastavirtalämmönsiirrintä tai poistoilmalämpöpumppua. Lisäksi tavoitteena oli mitata kahden ilmanvaihtokoneeseen liitettävän äänenvaimentimen vaimennuskyky ja pyrkiä parantamaan näiden vaimennusta. Työn teoriaosassa käsitellään yleisellä tasolla eri ilmanvaihtotapojen ja lämmöntalteenottomenetelmien toimintaperiaatteita ja soveltuvuuksiaeri tilanteisiin. Työn kokeellisessa osassa mitataan ilmanvaihtokoneen lämmöntalteenoton toiminta eri sääolosuhteissa ja lasketaan tulosten perusteella laitteelle lämpötila- ja entalpiavuosihyötysuhteet. Äänenvaimentimesta rakennetaan kaksi kehitysversiota, joiden mittaustuloksia verrataan alkuperäisen vaimentimen vaimennuskykyyn. Lämmöntalteenottoja vertailtaessa havaittiin, että suositeltavin kehitysvaihtoehto olisi vastavirtalämmönsiirtimeen siirtyminen sen yksinkertaisen rakenteen ja hyvän hyötysuhteen ansiosta.Äänenvaimentimien rakenteessa kannattaa mittausten ja pohdinnan perusteella siirtyä seinämillä jaettuun vaimentimeen.

Pientalojen ilmalämpöpumput sähköverkossa

Työssä tutkitaan ilmalämpöpumppujen kokonaisvaltaista vaikutusta sähköverkkoon. Tarkastelu aloitetaan lämpöpumppujen toiminnasta ja rakenteesta, josta jatketaan laitteen käytettävyyteen ja muiden lämmitysmenetelmien vertailuun. Sähköisten ominaisuuksien tarkastelussa pohditaan ilmalämpöpumppujen vaikutusta suomalaiseen sähköverkkoon muun muassa yleissähkötekniikan, taloudellisuuden ja energiatehokkuuden sekä häiriöiden kannalta. Tämä tutkielma rajoittuu pientaloihin, ja niihin asennettuihin ilma-ilmalämpöpumppuihin. Työn loppupäätelmänä on, että ilmalämpöpumppujen käytöstä ei juuri aiheudu vaikutuksia suomalaiseen sähköverkkoon. Suurimmat ilmalämpöpumppujen käytöstä syntyvät seuraukset kohdistuvat sähköverkkoyhtiöihin, joihin ilmalämpöpumput aiheuttavat taloudellisia menetyksiä. Suuret ja tulevaisuudessa kasvavat ilmalämpöpumppumäärät aiheuttavat sähköntuotantoon lisätehontarvetta huippukuorman aikaan. Toisaalta välitehoalueella tehontarve sekä energiankulutus pienenevät. Sähköverkoissa ei ole toistaiseksi havaittu ilmalämpöpumpuista johtuvia häiriöitä.

Germinability of Norway spruce and scots pine pollen exposed to open air

Summary

Effect of soil wetness on air composition and nitrous oxide emission in a loam soil

Selostus: Maan märkyyden vaikutus ilman koostumukseen ja dityppioksidiemissioon hiuemaassa

A combined infrared/heat pump drying technology applied to a rotary dryer

Selostus: Yrttien ja vihannesten infrapunakuivaus rumpukuivurissa

Performance Characteristics of an Axial-Flux Solid-Rotor-Core Induction Motor

The integration of electric motors and industrial appliances such as pumps, fans, and compressors is rapidly increasing. For instance, the integration of an electric motor and a centrifugal pump provides cost savings and improved performance characteristics. Material cost savings are achieved when an electric motor is integrated into the shaft of a centrifugal pump, and the motor utilizes the bearings of the pump. This arrangement leads to a smaller configuration that occupies less floor space. The performance characteristics of a pump drive can be improved by using the variable-speed technology. This enables the full speed control of the drive and the absence of a mechanical gearbox and couplers. When using rotational speeds higher than those that can be directly achieved by the network frequency the structure of the rotor has to be mechanically durable. In this thesis the performance characteristics of an axial-flux solid-rotor-core induction motor are determined. The motor studied is a one-rotor-one-stator axial-flux induction motor, and thus, there is only one air-gap between the rotor and the stator. The motor was designed for higher rotational speeds, and therefore a good mechanical strength of the solid-rotor-core rotor is required to withstand the mechanical stresses. The construction of the rotor and the high rotational speeds together produce a feature, which is not typical of traditional induction motors: the dominating loss component of the motor is the rotor eddy current loss. In the case of a typical industrial induction motor instead the dominating loss component is the stator copper loss. In this thesis, several methods to decrease the rotor eddy current losses in the case of axial-flux induction motors are presented. A prototype motor with 45 kW output power at 6000 min-1 was designed and constructed for ascertaining the results obtained from the numerical FEM calculations. In general, this thesis concentrates on the methods for improving the electromagnetic properties of an axial-flux solid-rotor-core induction motor and examines the methods for decreasing the harmonic eddy currents of the rotor. The target is to improve the efficiency of the motor and to reach the efficiency standard of the present-day industrial induction motors equipped with laminated rotors.

DFMA- Analysis and Aspects of Applying Internet Based Collaborative Design for Axial Eccentric Oil-Pump Design

The integrated system of design for manufacturing and assembly (DFMA) and internet based collaborative design are presented to support product design, manufacturing process, and assembly planning for axial eccentric oil-pump design. The presented system manages and schedules group oriented collaborative activities. The design guidelines of internet based collaborative design & DFMA are expressed. The components and the manufacturing stages of axial eccentric oil-pump are expressed in detail. The file formats of the presented system include the data types of collaborative design of the product, assembly design, assembly planning and assembly system design. Product design and assembly planning can be operated synchronously and intelligently and they are integrated under the condition of internet based collaborative design and DFMA. The technologies of collaborative modelling, collaborative manufacturing, and internet based collaborative assembly for the specific pump construction are developed. A seven-security level is presented to ensure the security of the internet based collaborative design system.

Practical applications of a systematic approach to the chemical abatement of pollutants in water and air

The present dissertation is devoted to the systematic approach to the development of organic toxic and refractory pollutants abatement by chemical decomposition methods in aqueous and gaseous phases. The systematic approach outlines the basic scenario of chemical decomposition process applications with a step-by-step approximation to the most effective result with a predictable outcome for the full-scale application, confirmed by successful experience. The strategy includes the following steps: chemistry studies, reaction kinetic studies in interaction with the mass transfer processes under conditions of different control parameters, contact equipment design and studies, mathematical description of the process for its modelling and simulation, processes integration into treatment technology and its optimisation, and the treatment plant design. The main idea of the systematic approach for oxidation process introduction consists of a search for the most effective combination between the chemical reaction and the treatment device, in which the reaction is supposed to take place. Under this strategy,a knowledge of the reaction pathways, its products, stoichiometry and kinetics is fundamental and, unfortunately, often unavailable from the preliminary knowledge. Therefore, research made in chemistry on novel treatment methods, comprisesnowadays a substantial part of the efforts. Chemical decomposition methods in the aqueous phase include oxidation by ozonation, ozone-associated methods (O3/H2O2, O3/UV, O3/TiO2), Fenton reagent (H2O2/Fe2+/3+) and photocatalytic oxidation (PCO). In the gaseous phase, PCO and catalytic hydrolysis over zero valent ironsare developed. The experimental studies within the described methodology involve aqueous phase oxidation of natural organic matter (NOM) of potable water, phenolic and aromatic amino compounds, ethylene glycol and its derivatives as de-icing agents, and oxygenated motor fuel additives ¿ methyl tert-butyl ether (MTBE) ¿ in leachates and polluted groundwater. Gas-phase chemical decomposition includes PCO of volatile organic compounds and dechlorination of chlorinated methane derivatives. The results of the research summarised here are presented in fifteenattachments (publications and papers submitted for publication and under preparation).

Numerical and ExperimentalModelling of Gas Flow and Heat Transfer in the Air Gap of An Electric Machine

This work deals with the cooling of high-speed electric machines, such as motors and generators, through an air gap. It consists of numerical and experimental modelling of gas flow and heat transfer in an annular channel. Velocity and temperature profiles are modelled in the air gap of a high-speed testmachine. Local and mean heat transfer coefficients and total friction coefficients are attained for a smooth rotor-stator combination at a large velocity range. The aim is to solve the heat transfer numerically and experimentally. The FINFLO software, developed at Helsinki University of Technology, has been used in the flow solution, and the commercial IGG and Field view programs for the grid generation and post processing. The annular channel is discretized as a sector mesh. Calculation is performed with constant mass flow rate on six rotational speeds. The effect of turbulence is calculated using three turbulence models. The friction coefficient and velocity factor are attained via total friction power. The first part of experimental section consists of finding the proper sensors and calibrating them in a straight pipe. After preliminary tests, a RdF-sensor is glued on the walls of stator and rotor surfaces. Telemetry is needed to be able to measure the heat transfer coefficients at the rotor. The mean heat transfer coefficients are measured in a test machine on four cooling air mass flow rates at a wide Couette Reynolds number range. The calculated values concerning the friction and heat transfer coefficients are compared with measured and semi-empirical data. Heat is transferred from the hotter stator and rotor surfaces to the coolerair flow in the air gap, not from the rotor to the stator via the air gap, althought the stator temperature is lower than the rotor temperature. The calculatedfriction coefficients fits well with the semi-empirical equations and precedingmeasurements. On constant mass flow rate the rotor heat transfer coefficient attains a saturation point at a higher rotational speed, while the heat transfer coefficient of the stator grows uniformly. The magnitudes of the heat transfer coefficients are almost constant with different turbulence models. The calibrationof sensors in a straight pipe is only an advisory step in the selection process. Telemetry is tested in the pipe conditions and compared to the same measurements with a plain sensor. The magnitudes of the measured data and the data from the semi-empirical equation are higher for the heat transfer coefficients than thenumerical data considered on the velocity range. Friction and heat transfer coefficients are presented in a large velocity range in the report. The goals are reached acceptably using numerical and experimental research. The next challenge is to achieve results for grooved stator-rotor combinations. The work contains also results for an air gap with a grooved stator with 36 slots. The velocity field by the numerical method does not match in every respect the estimated flow mode. The absence of secondary Taylor vortices is evident when using time averagednumerical simulation.