The dissertation investigates typical operation modes of the heat storage tank in the small-scale cogeneration (CHP) plant, analyses formation of thermal stratifi-cation in such storage tank and presents the simulation of the stratification. The main aim of the dissertation is to investigate peculiarities of operation modes of heat storage tank in small-scale CHP plant, develop an algorithm allowing to choose the storage tank volume and present a model allowing determination of thermal stratification in the storage tank at any time of its operation. / Disertacijoje nagrinėjami būdingi šilumos akumuliacinės talpos veikimo režimai, susiformuojantys nedidelės galios kogeneracinėje jėgainėje, tiriamas šiluminės stratifikacijos susidarymas tokioje talpoje ir atliekamas jos modeliavimas. Pagrindinis disertacijos tikslas – ištirti nedidelės galios kogeneracinės jėgainės šilumos akumuliacinės talpos veikimo režimų ypatumus, sudaryti algoritmą, padedantį parinkti tokios talpos tūrį ir pateikti modelį, leidžiantį nustatyti šiluminę stratifikaciją akumuliacinėje talpoje bet kuriuo jos veikimo metu.

Disertacijoje nagrinėjami būdingi šilumos akumuliacinės talpos veikimo režimai, susiformuojantys nedidelės galios kogeneracinėje jėgainėje, tiriamas šiluminės stratifikacijos susidarymas tokioje talpoje ir atliekamas jos modeliavimas. Pagrindinis disertacijos tikslas – ištirti nedidelės galios kogeneracinės jėgainės šilumos akumuliacinės talpos veikimo režimų ypatumus, sudaryti algoritmą, padedantį parinkti tokios talpos tūrį ir pateikti modelį, leidžiantį nustatyti šiluminę stratifikaciją akumuliacinėje talpoje bet kuriuo jos veikimo metu. / The dissertation investigates typical operation modes of the heat storage tank in the small-scale cogeneration (CHP) plant, analyses formation of thermal stratifi-cation in such storage tank and presents the simulation of the stratification. The main aim of the dissertation is to investigate peculiarities of operation modes of heat storage tank in small-scale CHP plant, develop an algorithm allowing to choose the storage tank volume and present a model allowing determination of thermal stratification in the storage tank at any time of its operation.

This Master’s thesis deals with design of heating source and heating system in the model object. Design is based on three variants of sources and heating systems. The first option is a heating pump air/water, the second option is pellet boiler and the third option is heating pump ground/water. At first heating losses are determined. Then heating systems and related heating sources are designed. The fundamental part of these free options is a design of alternative source for central heat and and hot water and heat storage. The last part is comparison of all variants.

The thesis deals with energy simulation of a solar energy system in a low-energy family house with warm-air heating. The simulations performed resulted in the assessment of the energy contribution of four solar systems with different types of collectors. The profitability and return of investment for the particular system have been evaluated based on investment costs and the savings gained. The theoretical part includes an introduction to the solar energy field, solar panel systems and the passive house concept. The practical part is devoted to description of the simulated object models as used in the TRNSYS environment, the simulation results evaluation along with the assessment of the economic return on investment. The conclusion recommendations regarding a suitable type and size of the solar panel with respect to the economic criteria chosen are given.