Browsing by Author "Kohonen, Reijo"
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- Aquifer thermal energy storage (ATES) system application for district heating and cooling
Insinööritieteiden korkeakoulu | Master's thesis(2018-09-24) Todorov Radoslavov, OlegAquifer thermal energy storage (ATES) systems in combination with groundwater heat pumps (GWHP) are promising and effective alternatives for integrated heating and cooling energy supply in buildings and district networks. In the present Thesis ATES systems are presented and addressed from different perspectives, such as their technical rationale, economic feasibility and environmental impact. Groundwater flow and thermal models are developed and calibrated, using a variety of available data sources (National Land Survey of Finland, Finnish Environment Institute) and tools (EXCEL, QGIS, MODFLOW, MT3DMS). Heat pump COP estimation analytical model is also implemented and coupled with the groundwater models. The purpose was to study different energy scenarios for ATES integration within the existing Pukkila's district heating network (Nivos Energia) as well as the long-term environmental flow and thermal impact generated to aquifer groundwater areas. Among the different researched scenarios, the most feasible strategy is to introduce a roughly constant cooling demand (proceeding from e.g. data center or industrial waste heat) in combination with the existing local district heating demand. The introduction of variable cooling demand using standard office simulated data is also modeled, having shown promising results. On the other hand, the "only heating" integration scenario has poor economic results, at least for the assumed present level of boiler's fuel price, and is reasonably feasible only in the case when prices increase. ATES systems are an efficient and a sustainable alternative for traditional fossil fuel boilers due to their capacity to annually store and recover cooling & heating energy from the subsurface. Significant technical and economical improvement could be achieved when simultaneous or seasonable cooling and heating loads are dispatched, within integrated district energy (heating & cooling) networks. - Rakennusten energia-analyysiohjelmien vertailu
Helsinki University of Technology | Master's thesis(1988) Kalliomäki, Pekka - Asuinhuoneistossa tarvittavien ilmavirtojen määrittäminen kuormitusten perusteella
Helsinki University of Technology | Master's thesis(1990) Saari, Mikko - Lämmön ja kosteuden siirtyminen rakenteissa
Helsinki University of Technology | Licentiate thesis(1980) Kohonen, Reijo - Lämmön talteenotto huokoisen materiaalin avulla
Helsinki University of Technology | Master's thesis(1977) Kohonen, Reijo - LVI-laitteiden sähkönkulutus HKR:n kiinteistöissä
Helsinki University of Technology | Master's thesis(1980) Hakkila, Jukka - Jaksottaisen lämmityksen optimointi itsevirittyvällä palautuslämmitysalgoritmilla
Helsinki University of Technology | Master's thesis(1990) Aho, Ilari - Rakennusmateriaalien kosteudenjohtavuuden ja vesihöyryn diffuusiokertoimen määrittäminen
Helsinki University of Technology | Master's thesis(1983) Ojanen, Tuomo - Rakennusten epäjatkuva ja jatkuva lämmitys
Helsinki University of Technology | Master's thesis(1980) Soininen o.s. Häkkinen, Pirkko - Rakennusten vuotoilmavirtausten lämpötekniset vaikutukset
Helsinki University of Technology | Licentiate thesis(1990) Virtanen, Markku - Technologies and solutions for ecocity's energy supply
School of Engineering | Master's thesis(2010) Sepponen, MariThis master's thesis presents a model and emissions calculations for the energy system of an ecocity. The system consists of energy producers and consumers as well as energy transmission and distribution. It has to provide efficient, adequate, and reliable energy supply in addition to being environmentally sustainable. Sustainability can be achieved by maximizing the energy efficiency and the share of renewable energy production as well as minimizing the energy consumption. All aspects of the energy system need to be tightly integrated, as a holistic energy system operates more efficiently, economically and ecologically. The whole system, including both electricity and thermal energy, is managed and optimized in real time with ICT solutions. The energy system is based on distributed energy production from renewable energy sources (mainly solar, wind and waste-to-energy), integrated district heating and cooling, and optimizations. The principles of cogeneration and trigeneration are used to increase profitability and energy efficiency. The thesis also includes a case study of an energy system of a Chinese city neighbourhood with 100.000 residents living in an area of 5 square kilometres. The study compares possibilities to reduce energy consumption and emissions for the whole life cycle of the energy system in four scenarios: firstly the base case representing the current situation, secondly the base case with CHP technology, thirdly the traditional ecocity model, and finally a high tech ecocity model with integrated ICT. In each case the emissions from the energy supply system during its entire life cycle are calculated with GEMIS software. The study finds a remarkable potential of reducing energy consumption in a typical Chinese city. Compared to the base case, the ecocity model shows a 40% reduction of electricity consumption and the high tech model 54% reduction. The energy consumption in heating and cooling systems can also be reduced significantly. Many potential targets for improving energy efficiency are recognized. Decreasing the energy consumption also directly cuts the emission rates. By replacing small coal boilers with a coal fired CHP plant and a distinct heating grid, the CO2 -equivalent emissions would be reduced by 16% compared to the base case. In the ecocity scenario, natural gas fired CHP technology gives 79% and CO2 -free energy production 97% reduction of CO2 -equivalent emissions. The ICT solutions in the high tech scenario give even further improvements; natural gas fired trigeneration achieves the CO2 -equivaient reduction of 83% and CO2 -free energy production the reduction of 98%. Other emissions follow this trend. Hence, the emissions from a Chinese city could he significantly reduced through the integration of more efficient technology. The results of the case study are scalable by the size of the population, and the ecocity and high tech solutions are well applicable to other projects, cities and targets. The reliability of the study is also confirmed by showing a correspondence to other information sources. - Vedenkäyttöön liittyvät säästötoimenpiteet julkisissa rakennuksissa ja suurpesuloissa
Helsinki University of Technology | Master's thesis(1981) Salmi, Ulla - Yhdistetty diffuusinen ja konvektiivinen lämmön ja aineen siirtyminen rakenteissa
Helsinki University of Technology | Licentiate thesis(1988) Ojanen, Tuomo