Browsing by Author "Kontu, Kaisa"

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Älykkäiden järjestelmien tuomat mahdollisuudet ja haasteet lämmitysmarkkinoilla
(2013-04-15) Mertanen, Antti
Insinööritieteiden korkeakoulu | Bachelor's thesis
Käyttöhyödykkeen valinnan vaikutus paperinvalmistuksen energian käyttöön
(2009) Kontu, Kaisa
Helsinki University of Technology | Master's thesis
Teollisuuden käyttöhyödykkeet, kuten sähköjärjestelmät, höyry- ja lauhdejärjestelmät, jäähdytysjärjestelmät sekä paineilma, eivät varsinaisesti tuota taloudellista tulosta tehtaalle, minkä takia niiden tärkeys usein sivutetaan. Käyttöhyödykkeiden optimoinnilla on kuitenkin tärkeä merkitys energiatehokkuuteen ja prosessin kannattavuuteen. Diplomityön kirjallisuusosassa tarkasteltiin metsäteollisuuden prosesseja keskittyen niiden energian käyttöön, käyttämiin käyttöhyödykkeisiin sekä siihen, miten käyttöhyödykevirrat kytkeytyvät toisiinsa. Diplomityössä tarkasteltiin käyttöhyödykkeen valinnan vaikutusta paperinvalmistuksen energian kulutukseen. Tarkastelu kohdistui Balas-ohjelmalla simuloituun tehdasintegraattiin, jossa on TMP-laitos ja paperikone. Tarkastelussa vertailtiin prosessivaihtoehtoja, jotka kohdistuvat paperikoneen tyhjöjärjestelmälle, puristinosalle sekä päällysteen kuivatukselle. Tyhjöjärjestelmälle tutkittiin vesirengaspumppuihin ja turbopuhaltimiin perustuvia järjestelmiä. Puristinosalla tutkittiin höyrylaatikon sekä kenkäpuristimen tuomia vaikutuksia energian kulutukseen. Päällysteen kuivatukselle tarkasteltavat vaihtoehdot olivat sähkö- ja kaasuinfra. Eri prosessivaihtoehtojen energian sekä käyttöhyödykkeiden kulutusta vertailtiin siten, että vertailun taserajoiksi valittiin koko tehdasintegraatti. Tarkastelun näkökulmaksi valittiin primäärienergian kulutus, jolloin eri energiavirtojen vertailu oli mahdollista. Tämän lisäksi selvitettiin CO2-päästöt sekä vaikutukset kustannuksiin. Tarkastelun tuloksista selvisi, että energiatehokkain ratkaisu tyhjöjärjestelmän osalta oli turbopuhallinvaihtoehto, jossa puhaltimien poistoilmaa käytetään hyödyksi sekundäärilämpönä. Kenkäpuristin vaihtoehdolla prosessihöyryn kulutus väheni yli 15 %. Päällysteen kuivatuksessa energian käytön kannalta järkevin vaihtoehto oli kaasuinfra. Höyrylaatikon lisääminen puristinosalle vähensi kuivatusosalla tarvittavaa energiaa mutta koko prosessia tarkasteltaessa huomattiin, että energian käyttö lisääntyi. Tässä esimerkissä havaittiin miten tärkeätä taserajojen oikea asettaminen energian kulutuksen tarkastelussa on. Työn tuloksia vertailtiin myös muihin kirjallisuuslähteisiin ja aikaisempiin tutkimuksiin. Primäärienergian kulutuksen tarkastelu eri prosessivaihtoehdoissa osoittautui hyväksi tavaksi tutkia energian kulutusta, jolloin eri käyttöhyödykkeiden energian kulutukset oli mahdollista huomioida. Tarkastelutapaa on mahdollista soveltaa myös muiden käyttöhyödykkeiden, kuten esimerkiksi paineilman, tarkasteluun sekä muiden teollisuudenalojen prosessien tarkasteluun.
City Scale Demand Side Management in Three Different-Sized District Heating Systems
(2018-12-01) Kontu, Kaisa; Vimpari, Jussi; Penttinen, Petri; Junnila, Seppo
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Demand side management can add flexibility to a district heating (DH) system by balancing the customer’s hourly fluctuating heat demand. The aim of this study is to analyze how different demand side management control strategies, implemented into different customer segments, impact DH production. A city scale heat demand model is constructed from the hourly heat consumption data of different customer segments. This model is used to build several demand side management scenarios to examine the effect of them on both, the heat producer, and the customers. The simulations are run for three different-sized DH systems, representing typical DH systems in Finland, in order to understand how the demand side management implementations affect the production. The findings imply that the demand side management strategy must be built individually for each specific DH system; the changing consumption profiles of different customer segments should be taken into consideration. The results show that the value of demand side management for a DH companies remains low (less than 2% in cost savings), having an effect mostly upon the medium loads without any significant decrease in annual peak heat loads. Also, the findings reflect that the DH pricing models should be developed to make demand side management more attractive to DH customers.
Hajautetun pientuotannon ilmastovaikutukset pohjoismaisessa energiajärjestelmässä
(2013) Olkkonen, Ville
School of Engineering | Master's thesis
The Nordic national climate and energy strategies aims to reduce the environmental loads caused by the buildings heating demand by using energy more efficiently and increasing the use of renewable energy sources, which can be attributed to the promotion of small scale distributed energy generation. This thesis examines the production phase climate impacts of small scale distributed energy generation technologies in the Nordic energy system. The analysis to determine short and potential long-term climate impacts has been performed by using life cycle analysis based on CLCA methodology and energy system analysis. These tools have been applied to model the climate impacts caused by the market dynamics and physical energy flows of the Nordic energy system. Consequently, a model that describes the current and potential future Nordic energy system was developed. In the short-term analysis supply and demand parameters were based on the Nordic national statistics, whereas the long-term analysis focused on modelling the effects of the EU 20-20-20 targets, and further the Nordic national climate and energy strategies targets for the energy system development, on greenhouse gas emissions in the long term. The analysis of Nordic energy system revealed that potential changes in the energy system have significant effect on the production phase climate impacts of small scale distributed energy generation technologies, and therefore, the short-and potential long-term emission factors may differ significantly. The effect of the change in magnitude and direction were found to be depended on the technology used and the sources of primary energy / fuel. By creating alternative policy, technology, and demand scenarios for the development of the energy system, this thesis also demonstrates that certain technologies are associated with uncertainty when CLCA methodology is used to determine the potential long-term emission factors, i.e. when analysing the impact far into the future, the uncertainty may grow larger than the actual effect,
Customer-centred development paths for district heating industry
(2020) Kontu, Kaisa
School of Engineering | Doctoral dissertation (article-based)
Heating and cooling accounts approximately 50% of final energy use in the European Union. District heating systems are seen as feasible energy technologies as part of sustainable energy systems and the market share is predicted to grow in the future. The main advantages of district heating systems are their ability to utilise heat that would otherwise be wasted. Also, the energy storing capacity of district heating systems in short term is expected to bring flexibility to energy systems. The literature underlines that current district heating systems should evolve towards lower temperature levels of networks as well as more versatile production mix. District heating research have concentrated on production and network while customers are often neglected part of the research and seen as consumption points in district heating network. The aim of this dissertation is to examine how district heating industry and its business models should be developed to involve customers. The starting point of the dissertation was that real estate owners seek lower heating costs as well as smaller risk towards increasing energy prices. This dissertation is constructed from four case-study articles. The articles discuss demand side management and heat pumps from perspectives of both customers and district heating system. The results of this dissertation show that from the customers' perspective it is profitable to change over from district heating to on-site heating system either partly or completely and implement demand side management. The results of the case studies found that on-site individual heat pumps are profitable heating systems for real estate owners with rate of returns being two or either three times higher than the property yields. Also, customers' control strategies in heat demand profile (demand side management) decrease heating costs. Understanding customers' perspective sheds light for upcoming changes in district heating industry. According to the results district heating industry should renew its business models, such as renewing pricing models, offer hybrid heating systems for customers and allow prosumers' waste heat into the district heating network, while adding value for the customers.
District heating and cooling as part of smart energy systems
(2015) Kontu, Kaisa
Insinööritieteiden korkeakoulu | Licentiate thesis
Energy systems are evolving and energy companies are required to take action to achieve higher levels of energy efficiency. Smart cities have been widely under discussion and smart energy systems are considered as the backbone of this approach. District heating and cooling (DHC) businesses are argued to be ‘important tools’ for reaching energy targets. The major objective of this research is to study the spedial characteristics of smart energy systems and how DHC systems are adapting to them. The most important factors for smart thermal grids are intelligence, efficiency, and flexibility in production and consumption, customer involvement, integration with other energy systems, and reliability. This study will present three case studies to highlight energy efficiency measures on the consumer side of a DHC system. The first study concentrates on the benefits of remote measurements and better implementation of a district heating (DH) forecasting model when consumer’s hourly measurements are utilized. The forecasting model was formed using linear regression, based on outdoor temperature data and the social component of the heat consumption. The study shows that forecasting models are more accurate for bigger customers and aggregated groups of customers and in the best cases a rather simple model predicts heat consumption with good accuracy. The second case study focuses on the flexibility of the DH network. The demand-side management (DSM) potential of district-heated residential buildings was determined by cutting heat for one hour during the morning consumption peak. Utilising the results of an earlier study, where the thermal behavior of eight different-aged residential buildings was simulated, the object of this research was to figure out the overall DSM potential of the buildings. The results showed that the thermal behavior of the buildings varies and that the buildings with the best potential for DSM were the ones built during the years 1940-2002. In the larger scale, the momentary heat effect decreased 80 percent due to DSM actions. The last case study concentrates on the original idea of the DH system, which is that heat can be recycled from sources where it otherwise would be wasted. A new business model is presented and critically evaluated, in which heat customers can sell their waste heat back to the energy company at a predetermined price. The pricing model is estimated relative to the waste heat suppliers as well as to the energy company. The results showed that, in general, it is profitable for heat customers to sell their waste heat in situations where the price of electricity is low, because then priming the temperature of the waste heat using heat pumps is affordable. System-wide, the results showed that emission levels were increased in most of the cases due to the priming of the waste heat. Despite of the results, this concept is an important opening for the energy and heat markets to include more waste heat in an energy system and thus decrease primary energy consumption.
From partial optimization to overall system management – Real-life smart heat load control in district heating systems
(2019-12-01) Kontu, Kaisa; Penttinen, Petri; Vimpari, Jussi; Junnila, Seppo
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
District heating (DH) customers are becoming increasingly interested in finding ways to decrease their heat consumption and costs. A general assumption is that demand side management (DSM) actions in heating stabilize consumption profiles, reducing consumption and peak demand. While several simulation studies have shown these assumptions to be true, much less is known about how real-life DSM actions affect the heat consumption profiles of buildings. This study analysed real-life consumption data from 109 DH customers over a period of four years. Thirty-one of those customers implemented DSM actions including permanent energy conservation and demand response actions with temporal effects with autonomous control (called Smart control, SC). The remaining 78 customers did not implement DSM and are used as a reference group. This study compared changes in the SC customers’ heat consumption profiles against the reference group and analysed how SC measurements reflect to DH system. The results show that these DSM actions decreased the heat consumption and costs for the customers but simultaneously increased short-term variations of heat load. This study highlights the need for greater co-operation between DH companies and their customers to develop more effective DSM control strategies that can provide better solutions for the whole system.
Hajautettu kaukolämpöjärjestelmä
(2012-12-12) Koskinen, Kalle-Heikki
Insinööritieteiden korkeakoulu | Bachelor's thesis
How to Promote Local District Heat Production Through Real Estate Investments
(2021-06) Penttinen, Petri; Vimpari, Jussi; Kontu, Kaisa; Junnila, Seppo
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Future energy systems must be clean, efficient and profitable. Previous cases have shown that incorporating local production into district heating networks is often unprofitable due to high temperature levels. This article suggests a new way of determining areas in existing networks suitable for low temperature district heating, which makes investments by real estate owners into local production profitable. A simulation of district heating network is used together with an investment optimization model to analyse the spatial potential of local production. The results show that some local production was profitable at current temperature levels, but it could be increased significantly if supply temperatures are decreased. This was shown to decrease losses and emissions of the system. Spatial optimization models are needed to increase knowledge on the effects of local production and lower network temperatures in district heating networks. Furthermore, new pricing models for customers have to be developed.
Individual ground source heat pumps : Can district heating compete with real estate owners' return expectations?
(2020-02-01) Kontu, Kaisa; Vimpari, Jussi; Penttinen, Petri; Junnila, Seppo
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Technological development has decreased costs and improved the efficiency of heat pumps (HPs). In some cases, heat produced with HPs is already less expensive compared to district heating (DH) systems that have high market shares in many European countries. This has generated a phenomenon in which old customers are leaving DH systems, and new customers are not joining DH even if it is available. The study evaluates the economic performance of alternative heating systems (DH, ground source HP with electricity, and a hybrid of these two) for new buildings in selected city in Finland: residential, office, retail and industrial. The aim of this study is to demonstrate the rationale for property owners to invest in ground source HPs. In addition, the study examines whether DH pricing can be developed to improve the competitiveness against HP systems. The results show that currently, HPs are highly profitable for all studied customer types with current DH pricing models used in selected DH company. However, with new pricing models, the competitiveness of DH improves substantially. In conclusion, we suggest that DH companies renew their pricing models to include several customers segments as well as hybrid heating customers.
Kaukolämmön hinnoittelu ja markkinat
(2013-04-24) Einolander, Johannes
Insinööritieteiden korkeakoulu | Bachelor's thesis
Kiinan energiantuotanto nyt ja tulevaisuudessa - uusiutuvat energiantuotantomenetelmät
(2012-04-25) Räty, Sanna
Insinööritieteiden korkeakoulu | Bachelor's thesis
Kiinan energiantuotanto nyt ja tulevaisuudessa - ydinvoima ja fossiiliset polttoaineet
(2012-04-24) Laine, Anssi Markus
Insinööritieteiden korkeakoulu | Bachelor's thesis
Teollisuuden jätelämmön hyödyntäminen kaukolämmöntuotannossa
(2011) Karppinen, Antti
Insinööritieteiden korkeakoulu | Bachelor's thesis
Teollisuuden jätelämmön hyödyntäminen sähköntuotannossa Suomessa käyttäen ORC-prosessia ja Stirling-konetta
(2012) Turunen, Jukka Pekka
Insinööritieteiden korkeakoulu | Bachelor's thesis
Uncertain Greenhouse Gas Implication in Waste Heat Utilization – A Case Study with a Data Center
(2020-06) Laine, Jani; Kontu, Kaisa; Heinonen, Jukka; Junnila, Seppo
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Waste heat utilization is shown to have the potential to decrease greenhouse gas emissions globally. The purpose of this case study is to illustrate how the utilization of waste heat to decrease municipal boundary greenhouse gas emissions may increase such emissions within wider boundaries. The case study assesses the utilization of waste heat generated by a data center. In this paper, we analyze the implications within Scopes 1-3 of the Greenhouse Gas Protocol together with attributional and consequential life cycle assessment principals. Only Scope 1 showed negative greenhouse gas emission implications. In order to achieve negative Scope 2 emissions, approximately half of the waste heat would need to be utilized, which is the purpose of further site development. In order for negative Scope 3 emission implications, electricity production changes are needed or local municipal replaceable greenhouse gas emissions would need to be much higher.
Wood chip drying in connection with combined heat and power or solar energy in Finland
(2014) Rinne, Samuli; Holmberg, Henrik; Myllymaa, Tiina; Kontu, Kaisa; Syri, Sanna
A4 Artikkeli konferenssijulkaisussa
20% of the Finnish district heating (DH) power plant fuels are wood-based and the share is increasing. The wood fuel demand probably exceeds the potential supply in the future. The wood fuel drying with waste heat is one profitable opportunity to gain more wood fuel. If the drying energy can be produced with lower primary energy use than combusting the fuel directly, the drying potentially improves the system efficiency. In this study, the drying feasibility in the connection of a combined heat and power (CHP) system, possibly with solar collectors, is calculated. The wood fuel heating can be increased profitably by 6%, using the heat from CHP for drying only when the marginal cost of the heat is low enough, i.e. the electricity price is high enough and there is free capacity after the DH demand. Although the drying is profitable, a larger heat storage can also increase the annual result similarly. The best investment choice depends on the plant properties. Here the optimal system enables 20% DH production cost savings. Solar heat may be profitable, when the solar heat has a 2–3% share of the annual heat demand. However, the dryer or larger storage tank are more profitable investments.