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Description of the subject. Date (Phoenix dactylifera L.) seed waste, from the date industry in Mexico, is an attractive source of biomass for bioenergy due to its renewability, availability, and not being otherwise usable. Objectives. In this research project, we calculated and determined the amount of biofuel that could potentially be used from the thermal energy recovery of raw date seed (RDS) and processed date seed (PDS) through oil extraction. Method. The physicochemical composition and thermal behavior of RDS and PDS was determined to evaluate their usefulness for thermal energy production. Proximate and thermogravimetric analyses, Scanning Electron Microscope imaging, and different fuel properties such as Higher Heating Value (HHV), bulk, and energetic density and Fuel Value Index (FVI), were determined. Furthermore, the potential energy production from seed waste of the Mexican date industry was estimated. Results. The RDS presented better HHV 19.33 MJ.kg-1 and energetic density 14.42 MJ.m-3, however, PDS has lower moisture 5.12% and ash content 5.89%. The FVI of PDS is more favorable than RDS, 363.81 and 208.43 respectively. Conclusions. The potential energy production from date seeds produced in Mexico in 2018 was calculated RDS 10.17 TJ, PDS 8.04 TJ and Biodiesel 2.01 TJ and with a tendency to increase every year.

Recent proposals to reorganise the French reactor industry to increase its export capability are reviewed here. Based on its criticism of the technology on offer to export markets, the Rousselly report recommended making the national electricity company a lead company free to negotiate the sale of reactors of its choosing (including Gen2 reactors) and to make the French manufacturer the sub-contractor of the former. The Government did not adopt these recommendations and rightly so. Based on an analysis of the changing world market for reactors, perspective can be gained on the criticism made of Areva about its marketing thrust, as well as the advantage to be gained by broadening its reactor catalogue. This analysis brings out and underlines the significance of the technological and industrial resources of Areva relative to competitors and the relatively meager advantage of architect/assembler and operator provided by the national electricity company in the conquest of export markets. In the final analysis, the mercantile approach proposed by the champions of this reform to improve competitiveness with low cost nuclear newcomers was ruled out by the Government, even before the Fukushima accident. What is really required is a little more export coordination between the two entities. [PUB ABSTRACT]

With the appropriate computer program numerous thermal calculations of the furnace are done, based on the presented one-dimensional zonal method. The results of the calculation are compared with the results of measuring of testing model: Furnace chamber of steam boiler unit OP-650b in TP Kosovo-A, Obilic, Serbia and Montenegro. Comparison of the calculating results and measuring results lead to conclusion that the proposed methods is suitable for the calculation of thermal regime in a furnace chamber of large power boilers in the case when thermal resistance of deposits is great, variable in time and different in some parts. Also, the method is very suitable for analysis of real conditions in the furnace in which the conditions of furnace work are different from the projected one, as well as for simulation of various operating conditions.

Precise and reliable meteorological data are necessary for building performance analysis. Since meteorological conditions vary significantly from year to year, there is a need to create a test reference year (TRY), to represent the long-term weather conditions over a year. In this paper two different TRY data models were generated and compared: TRY and TRY-2. Both models where created by analysing every 3-hour weather data for a 30-year period (1984–2013) in Alūksne, Latvia, provided by the Latvian Environment Geology and Meteorology Centre (LEGMC). TRY model was generated according to standard LVS EN ISO 15927-4, but to create second model - TRY-2, 30 year average data were applied. The generated TRY contains typical months from a number of different years. The data gathered from TRY and TRY-2 models where compared with the climate data from the Latvian Cabinet of Ministers regulation No. 379, Regulations Regarding Latvian Building Code LBN 003-01. Average monthly temperature values in LBN 003-01 were lower than the TRY and TRY-2 values. The results of this study may be used in building energy simulations and heating-cooling load calculations for selected region. TRY selection process should include the most recent meteorological observations and should be periodically renewed to reflect the long-term climate change.

The study aims to survey the practices of private individuals, who become energy producers (with photovoltaic panels, heat pumps, micro-cogeneration...). The underlying issue of this quality survey is as follows: does becoming an energy producer change energy consumption modes ? And if so, in what direction? Various practices have therefore been described and analysed depending on the type of energy produced, the market maturity phase, the respondents' awareness of the world of technology, their life style, or their level of environmental commitment. Based on those observations, one can only acknowledge that the connection between controlled energy consumption and decentralised energy production is far from being straightforward and recommendations have been made to improve the synergy between those two variables. [PUB ABSTRACT]

This study aims to investigate by, 1H NMR the thermal oxidation kinetics of sesame oil (SO) and commercial sesame oil (CSO) obtained from roasted and unroasted seeds, respectively. The samples were heated at 180 deg C by 8 hours per day for 15 days. The 1H NMR data analysis indicated that the hydrogen concentration decreases during 96 h of heating, remaining at 69.51 percent, 60.63 percent and 42.69 percent of allylic (E), vinylic (V) and bis-allylic (G) hydrogen in SO, and 49.29 percent, 38.51 percent, 18.58 percent in CSO, respectively. Behaving as the first order oxidation kinetics, SO average rate constant (k = mol.L-1.h-1) was: kG = 0.088 more then kV = 0.0052 more then kE = 0.0037 and half-life period (h), t1 per 2(E) = 188.37 more then t1 per 2 (V) = 134.56 more the more then t1 per 2 (G) = 79.04. To CSO, kG = 0.0169 more then kV = 0.0101 more then kE = 0.0074 and t1 per 2(E) = 94.18 more then t1 per 2 (V) = 68.49 more then t1 per 2 (G) = 41.12. These results indicated that SO is more resistant to thermal oxidation [less then k, more then t1 per 2] than CSO [more then k, less then t1 per 2]. The study allowed to conclude that sesame oil obtained from unroasted samples has higher thermal-stability than commercial sesame oil from roasted seeds and that their cannot be used after 14.3 and 3.6 hours, respectively, for deep-frying purposes at 180 deg C.

The aim of the study is to determine whether and to what extent it is possible to use excess electricity produced by wind power plants during low demand periods for district heat production by heat pumps. Energy system analysis on an hourly basis is conducted at various capacities of wind power plants. The results show that it is possible to increase the share of renewable energy sources, decrease the use of primary energy sources and CO2 emissions per unit of the produced energy, i.e. heat and electricity, by using the surplus electricity produced by wind power in the heat pumps combined with the heat storage. Centralizētās siltumapgādes sistēmām nākotnē būs pieaugoša nozīme atjaunojamo energoresursu īpatsvara palielināšanā valsts energobilancē. Nozīmīgi pieaugot vēja elektrostaciju saražotās elektroenerģijas īpatsvaram elektroapgādes sistēmā, aktuāls kļūs jautājums par pārpalikuma elektroenerģijas izmantošanu zema patēriņa stundās. Tādēļ nepastāvīgas jaudas atjaunojamo energoresursu elektrību ražojošu avotu plašāka izmantošana un integrēšana energoapgādes sistēmās prasīs patērētājus, kuri elastīgi spēj mainīt patēriņu atbilstoši avotu piegādes iespējām. Centralizētās siltumapgādes sistēmas zināmā apmērā spēj būt elastīgs elektroenerģijas patērētājs un veikt nepastāvīgas jaudas atjaunojamo energoresursu tehnoloģiju ražotās elektroenerģijas izmantošanu. Darba mērķis ir izpētīt, kādā apmērā centralizētās siltumapgādes sistēmas spēj izmantot vēja elektrostaciju ražoto elektroenerģijas pārpalikumu zema patēriņa stundās, lietojot siltuma sūkņu un siltuma akumulatoru iekārtas. Izpētes uzdevums ir noteikt, vai un cik lielā mērā ir iespējams palielināt atjaunojamo energoresursu īpatsvaru un samazināt oglekļa dioksīda emisijas elektroenerģijas un centralizētās siltumenerģijas ražošanas procesā, izmantojot vēja ražoto elektroenerģiju siltuma sūkņu iekārtās. Centralizētās siltumapgādes un elektroapgādes sistēma ir pētīta, lietojot energosistēmu analīzes modelis “EnergyPLAN”, kurš ļauj analīzi veikt stundu griezumā, un analizēt dažādu tehnoloģiju kombinācijas. Darba rezultāti parāda, ka vēja elektrostaciju ražotās pārpalikuma elektroenerģijas lietošana siltuma ražošanai siltuma sūkņu iekārtās, kas apvienotas ar siltuma akumulatoriem centralizētās siltumapgādes sistēmās, ļauj samazināt primāro energoresursu patēriņu un CO2 emisijas, un palielināt atjaunojamo energoresursu īpatsvaru, rēķinot uz vienu saražotās enerģijas (siltuma un elektrības) vienību.

The aim of the study was to identify the similarities and differences in the phytoplankton in lakes Licheńskie and Ślesińskie based on the phytoplankton species composition and biomass. Quantitative and qualitative studies of phytoplankton from two heated lakes were conducted in 2004-2005. A total of 280 and 240 taxa were identified belonging to six phyla: Chlorophyta, Cyanoprokaryota, Cryptophyta, Dinophyta, Euglenophyta, and Heterokontophyta. Most of the taxa were incidental species with frequencies of less than 25%. The phytoplankton biomass in Lake Licheńskie ranged from 0.2 to 8.6 mg dm -3 . Throughout the growing season of 2004, the phytoplankton observed was comprised of diatoms and green algae, while in 2005 it was comprised of diatoms, green algae, and cryptophytes. The phytoplankton biomass in Lake Ślesińskie ranged from 0.4 to 13.2 mg dm -3 . Diatoms dominated in this lake in the spring and fall of both years (54-90%), while in summer 2004 diatoms and green algae dominated and in summer 2005 the dominants were cryptophytes, dinophytes, and cyanophytes. Na podstawie ilościowej i jakościowej analizy fitoplanktonu (skład gatunkowy, różnorodność taksonomiczna, biomasa ogólna wraz ze strukturą dominacji) wykazano podobieństwa i różnice rozwijającego się planktonu roślinnego w jeziorach Licheńskim i Ślesińskim. Badania prowadzono od marca do listopada w latach 2004-2005. Zidentyfikowano odpowiednio: 280 (J. Licheńskie) oraz 240 taksonów (J. Ślesińskie), które należały do 6 gromad: Chlorophyta, Cyanoprokaryota, Cryptophyta, Dinophyta, Euglenophyta oraz Heterokontophyta. Większość taksonów należała do gatunków przypadkowych, z frekwencją 0-25%. W J. Ślesińskim zaobserwowano ponadto większą liczbę gatunków absolutnie stałych i stałych niż w J. Licheńskim.W Jeziorze Licheńskim glony planktonowe utworzyły biomasę w zakresie od 0,2 do 8,6 mg dm -3 . W całym sezonie wegetacyjnym 2004 roku obserwowano fitoplankton o charakterze okrzemkowo-zielenicowym, a w 2005 roku okrzemkowo-zielenicowo-kryptofitowym. W Jeziorze Ślesińskim fitoplankton utworzył biomasę w zakresie od 0,4 do 13,2 mg dm -3 . Wiosną i jesienią w zbiorowiskach dominowały okrzemki (54-90%), natomiast latem współdominowały okrzemki i zielenice w 2004 roku oraz kryptofity, dinofity i sinice w 2005 roku. Wartości wskaźnika różnorodności Shannona-Weavera w Jeziorze Licheńskim średnio wynosiły: H n ' - 2,23; H b ' - 2,52, natomiast w Jeziorze Ślesińskim były niższe - H n ' - 2,08; H b ' - 2,10.Fitoplankton Jeziora Licheńskiego i Ślesińskiego kształtował się w obliczu odmiennych cech tych zbiorników, uwzględniających morfometrię, typ mieszania, czas retencji wody, zawartość tlenu, termikę wód oraz biodostępność fosforu. O odrębności planktonu roślinnego w obu jeziorach zadecydowała głównie różna liczebność i frekwencja taksonów oraz skład letniego zbiorowiska. Potwierdzeniem stały się różne wartości wskaźnika różnorodności gatunkowej Shannona-Weavera. Dość duże podobieństwo stwierdzono natomiast pod względem biomasy ogólnej oraz struktury wiosennego i jesiennego fitoplanktonu.

The paper is focused on analysis of the current situation for the solar thermal system market in Latvia. Solar energy potential and solar thermal market development in Latvia is compared with those in the countries, where solar irradiation is equivalent to that of the Latvian climate. This research also includes a description of the solar and pellet combisystem installed for a demonstration pilot project; the main parameters of this system are identified and the performance data for the first month of operations is analysed. An economic analysis for different heat supply scenarios from simulation data and real performance of the system is shown. Enerģētikas sektors spēlē nozīmīgu lomu ikvienā valstī. Ilgtspējīga enerģētikas politika nodrošina stabilu ekonomisko izaugsmi un pasargā vietējo tirgu no straujām enerģijas cenas izmaiņām. Eiropas Savienība (ES) ir noteikusi, ka līdz 2030. gadam ES-25 valstīm 20% no siltumenerģijas pieprasījuma jānodrošina, izmantojot saules enerģiju. Lai sasniegtu šo mērķi, Eiropas līmenī tiek īstenoti dažādi izpētes un attīstības projekti. Pētījums ietver informāciju par saules siltuma tehnoloģiju tirgus attīstību Latvijā. Saules enerģijas potenciāls un tirgus izaugsme Latvijā tiek salīdzināta ar citām valstīm, kur pieejamais saules radiācijas daudzums ir ekvivalents Latvijas klimatiskajiem apstākļiem. Ar Eiropas Savienības finansiālo atbalstu tika īstenots Rīgas Tehniskās universitātes Vides aizsardzības un siltuma sistēmu institūta un trīs Latvijas uzņēmumu sadarbības projekts „Kompaktais saules un granulu modulis”. Projekta ietvaros tika izveidota kompakta katlu mājā, kurā tika uzstādīta saules un granulu kombisistēma. Saules un granulu kombisistēma nodrošina apkuri un karstā ūdens sagatavošanu vienai daudzdzīvokļu ēkai Siguldā. Publikācijā tiek iekļauts saules un granulu kombisistēmas pilotprojekta apraksts, definēti galvenie sistēmas raksturlielumi un analizēti pirmo piecu mēnešu darbības rezultāti. Tiek salīdzināti dažādi siltumapgādes sistēmu scenāriji renovētai un nerenovētai ēkai ņemot vērā izdevumus resursu iegādei.

District heating networks in Estonia are mostly old and in bad condition. The state of the district heating networks of Tallinn is typical for the rest of Estonian DH networks. The paper includes an analysis of the Tallinn district heating networks. Valid data about damages in district heating systems received for the last 12 years were used for an analysis of the network damages. Different types of network damages are analysed: external corrosion, internal corrosion, defect of installation, factory defects, defect of construction and other reasons. The scale of damages for the different elements of networks is compared in the paper: armature, compensator, construction and pipes. The main factors which influence damages in district heating networks are the age of networks, the quality of construction works and the network operation conditions. The damage quantity dependence on the age of networks is also defined and analysed in the paper. The scale of damages can be diminished by reducing the average age of the networks. This is possible by replacing old pipelines and other network system elements. The pipes average age changes for a 20 year period are simulated according to different intensities of renovation works. Rakstā veikta Tallinas centrālās apkures tīklu analīze. Ticami dati tika saņemti par 12 gadiem un izmantoti tīklu bojājumu analīzei. Dažādiem siltumtīklu bojājumiem tika izanalizēti: ārējā korozija, iekšējā korozija, uzstādīšanas defekti, rūpnīcas defekti, būvniecības defekti un citi. Rakstā tika salīdzināti dažādu tīkla elementu bojājumi: armatūras, kompensatoru, cauruļu un konstrukciju. Galvenie faktori, kuri ietekmē bojājumu daudzumu, ir tīklu vecums, būvniecības darbu kvalitāte un tīklu darbības apstākļi. Šajā rakstā ir noteikta un izanalizēta bojājumu daudzuma atkarība no tīklu vecuma. Bojājumu daudzumu var samazināt, nomainot vecos cauruļvadus un citus tīkla elementus. Siltumtīklu cauruļu vidējais vecums tuvākajiem divdesmit gadiem tika prognozēts, ņemot vērā renovācijas darbu dažādo intensitāti.