Tag Archives: energy efficiency

439-450 K. Bumbiere, S. Sereda, J. Pubule and D. Blumberga
The role of energy management in the agricultural sector: key prerequisites and impacts
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The role of energy management in the agricultural sector: key prerequisites and impacts

K. Bumbiere*, S. Sereda, J. Pubule and D. Blumberga

Riga Technical University, Faculty of Electrical and Environmental Engineering, Institute of Energy Systems and Environment, Azenes street 12/1, Riga LV 1048, Latvia
*Correspondence: ketija.bumbiere@rtu.lv

Abstract:

Agriculture is one of the most energy-consuming sectors in the EU’s economy. Implementing sustainable agriculture to reduce GHG emissions and increase energy efficiency through energy management is a crucial strategy to tackle climate change. In this paper, the role of energy management in the agricultural sector is studied, and experiences from Europe and the world have been considered. Literature analysis regarding the chosen topic has been conducted, including the methodology of energy management plan development and its implementation in the case study of Latvia. Data from Latvia’s agricultural and other sectors have been analysed and compared. Latvia’s Inventory Report regarding GHG emissions in the agricultural sector was reviewed, and all emission sources in the agricultural sector were highlighted. The primary purpose of the study is to find out if energy management were introduced in an agricultural company, what would be the potential GHG emission, energy savings and additional advantages. Two companies working in Latvia were surveyed, and potential emission and energy consumption reduction measures in agriculture that would be applied to companies were developed. The research showed that by implementing the basic principles of energy management, it would be possible to reduce the average energy consumption by 17%. If measures are applied to reduce GHG emissions from agricultural companies, the average emissions would be reduced by 43%.

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2148-2155 M. Miljan, M.-J. Miljan, K. Keskküla (Leiten) and J. Miljan
The combined impact of energy efficiency and embodied energy of external wall over 30 years of life cycle
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The combined impact of energy efficiency and embodied energy of external wall over 30 years of life cycle

M. Miljan, M.-J. Miljan*, K. Keskküla (Leiten) and J. Miljan†

Estonian University of Life Sciences, Institute of Forestry and Rural Engineering, Chair of Rural Building and Water Management, Fr. R. Kreutzwaldi 5, EE51006 Tartu, Estonia
*Correspondence: martti-jaan.miljan@emu.ee

Abstract:

Decreasing the energy consumption in production and building activity is the main aim nowadays as well as in the future. Taking into account that almost 50% of European Union’s final energy consumption is used for heating and cooling, of which 80% is used in buildings it is essential to minimize this amount beforehand. Looking at the energy losses we see that the main heat losses are caused due to the transmission through the envelope and ventilation system.
EU energy efficiency target for buildings to 2030 is at least 32.5%. According to this, national energy efficiency action plans were done, which mean that existing building stock need renovation and new buildings will be constructed according to the energy efficiency requirements. One important factor to improve energy efficiency is to modify thermal transmittance of the envelope. In 2017 minimum energy efficiency requirements were validated in Estonia and determined that the thermal conductance of outer wall must be less than 0.22 W m-2 K-1 (recommended range of U = 0.12–0.22 W m-2 K-1). According to this the energy loss through the envelope was calculated over the year taking degree-days as bases. In our area this number is 4,933 degree days per year, what gives us the calculated heat loss through the envelope 10.22 kWh m-2 if the thermal conductance of the wall is 0.092 W m-2 K-1. This required value of thermal conductance we can achieve using good insulation materials. Still there are possibilities to choose between insulations.
Done tests and calculations allow to conclude that energy consumption during building life cycle together with embodied energy of building materials gives us more realistic overview of the energy efficiency of the building. Our results confirm that the use of local natural insulation materials is 1.67 times more sustainable and energy saving than using industrial materials.

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2166-2184 J.L. Paes, B.C. Vargas, J.P.B. Cunha, D.S.C. Silva, G.A.S. Ferraz, M.R.S. Braz, P.F.P. Ferraz, L. Conti and G. Rossi
Thermal performance of a solar hybrid dryer for Conilon coffee (Coffea canephora)
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Thermal performance of a solar hybrid dryer for Conilon coffee (Coffea canephora)

J.L. Paes¹*, B.C. Vargas¹, J.P.B. Cunha¹, D.S.C. Silva¹, G.A.S. Ferraz², M.R.S. Braz¹, P.F.P. Ferraz², L. Conti³ and G. Rossi³

¹Rural Federal University of Rio de Janeiro, Engineering Department, Campus Seropédica, ZIP Code BR23890000, Seropédica, Rio de Janeiro, Brazil
²Federal University of Lavras, Agricultural Engineering Department, ZIP Code BR37200000, Lavras, Minas Gerais, Brazil
³University of Florence, Department of Agricultural, Food, Environment and Forestry (DAGRI), Via San Bonaventura, 13, IT50145, Florence, Italy *Correspondence: juliana.lobop@gmail.com

Abstract:

The study was aimed at design and development of an energy efficient hybrid solar dryer suitable for drying of organic Conilon coffee placed in the town of Seropédica, Rio de Janeiro, Brazil. The energy efficiency and the drying efficiency were the evaluation criteria for thermal performance of the hybrid solar dryer during the coffee drying. Temperature and relative humidity (RH) of the drying and ambient air, solar radiation intensity and coffee weight loss were monitored during the drying process. The process occurred over six consecutive days; the drying time was from 07:00 to 17:00 h, totalling 120 h of operation with an intermittent period (at night) of 14 h. During intermittence, the exhaust system kept off and solar collector and drying chamber sealed. The effective drying period took 60 h, with temperature and RH, respectively, of 38.3 °C and 60.6% outlet of the solar collector, 32.7 °C and 72.2% outlet drying chamber and 27.8 °C and 74.5% ambient air. The maximum temperature in the solar collector and drying chamber reached 54 and 47.7 °C, respectively, with an ambient air temperature of 32 °C at 12:00 h. These values showing temperature increase 22.2 °C in solar collector and 10 ºC drying chamber. The mean variation for the reduction in RH between the drying air inside the solar collector and the ambient air was 28%, while in the chamber obtained in a range of 10.5% at 13:00 h. The solar collector and dryer chamber efficiency were 29.1 and 40.8%, respectively, while the overall dryer efficiency 39.7%.

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1097–1106 K. Leiten, P. Kirotar and M. Kiviste
Hygrothermal analysis of masonry wall with wool glass interior insulation
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Hygrothermal analysis of masonry wall with wool glass interior insulation

K. Leiten*, P. Kirotar and M. Kiviste

Estonian University of Life and Science, Institute of Forestry and Rural Engineering, Kreutzwaldi 5, EE51014 Tartu Estonia
*Correspondence: kadri.keskkyla@mail.ee

Abstract:

When the external appearance of the building is fixed due to heritage requirements the interior thermal insulation is the only possible solution for thermal upgrade of the building envelope. Applying internal insulation to existing buildings is known to pose a challenge in relation to hygrothermal risks, as this can lead to high relative humidity levels, condensation and ultimately, mould growth and decay. The case study building is under historical preservation and therefore this is not allowed to be insulated from outside. The paper describes the hygrothermal assessment of applying internal glass wool insulation and vapour barrier in masonry wall with air gap. In addition to the calculations the condition investigation was also performed. Data loggers measuring temperature and RH were applied during the period of 31.01.2013–16.02.2013. The conclusions were based to theoretical calculations (case study and DIN 4108-3) and practical measurement results based on the data logger values obtained. The calculations showed that glass wool and vapour barrier insulated system were in risk on condensation but the condensed water dries out during summer time. Due to the fact that logger measurements were recorded during the time when inside plastering was still in progress the relative humidity in the room was very high. As a result of calculations it is possible to build this type of wall effectively, but in this case it was not the most reliable way because of ongoing interior fitting.

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322–328 M. Bloch-Michalik and M. Gaworski
Agricultural vs forest biomass: production efficiency and future trends in Polish conditions
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Agricultural vs forest biomass: production efficiency and future trends in Polish conditions

M. Bloch-Michalik* and M. Gaworski

Department of Production Management and Engineering, Warsaw University of Life Sciences, PL02-787 Warsaw, Nowoursynowska str. 164, Poland
*Correspondence: marta_michalik@sggw.pl

Abstract:

Biomass is one of the main sources of renewable energy with rapidly growing trend in the European Union countries. The technical potential of biomass energy in Poland is one of the highest in Europe, estimated at approximately 900 PJ/year. Solid biomass is the primary Polish RES and the share in the structure of production in Poland amounted to almost 77% in 2015. The most common types of biomass are waste raw materials from crop fields and forests.
The paper presents current potential of the biomass of two basic types, i.e. agricultural and forest material, based on the analyses developed with the scenario forecast of future use in Poland. Detailed considerations include differences in efficiency of agricultural and forest biomass production. To develop the efficiency aspects some indices were proposed to compare potential of energy production basing on different kind of biological material.

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520-525 T. Prodanuksand D. Blumberga
Methodology of demand side management Study course. experience of case studies
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Methodology of demand side management Study course. experience of case studies

T. Prodanuks*and D. Blumberga

Riga Technical University, Faculty of Power and Electrical Engineering, Institute of Energy Systems and Environment, Azenes street 12-K1, LV1043 Riga, Latvia; *Correspondence: toms.prodanuks_1@rtu.lv

Abstract:

The role of environmental and energy security issues due to political issues are increasing and this stimulates governments to review sustainable energy strategies. One of the ways to reach the targets set by many countries for cuts in greenhouse-gas emissions, free competition and security of supply is energy efficiency. Energy efficiency can be achieved by demand side management (DSM) programs. DMS requires regular and intensive work with energy users and it makes a platform for introduction of DSM strategies in engineering education. The paper discusses the integration models of DSM in the engineering education, analyses the components significant for ensurance of sustainable engineering education and energy efficiency and climate change targets. Based on analysis a methodology for of integration of DSM is developed. Methodology shows how to introduce environmental specialists, students and municipality employees with demand side management in public buildings and how to evaluate efficiency of such integration. Methodology is analysed through several case studies and conclusions and recommendations developed.

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89-94 T. Jokiniemi, T. Oksanen and J. Ahokas
Continuous airflow rate control in a recirculating batch grain dryer
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Continuous airflow rate control in a recirculating batch grain dryer

T. Jokiniemi*, T. Oksanen and J. Ahokas

University of Helsinki, Faculty of Agriculture and Forestry, Department of Agricultural Sciences, P.O. Box 28, 00014, University of Helsinki, Finland;
*Correspondence: tapani.jokiniemi@helsinki.fi

Abstract:

As the energy efficiency requirements in agriculture increase, offers grain drying opportunities for substantial energy saving. Earlier work indicated that energy savings in grain drying can be achieved by controlling the drying airflow rate during the drying process. Aim of this study was to design an embedded control system, based on microcontroller, for continuous airflow rate control in a recirculating batch grain dryer, and to test it in a scaled-down research dryer. The control system proved to be working as designed, reducing the dryer airflow rate smoothly towards the end of the process. However, additional research of the energy efficiency and performance of the dryer using the airflow rate control is needed.

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491-498 E. Kamendere,, A. Zandeckis, A. Kamenders, J. Ikaunieks and C. Rochas
Mechanical ventilation with a heat recovery system in renovated apartment buildings
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Mechanical ventilation with a heat recovery system in renovated apartment buildings

E. Kamendere¹,*, A. Zandeckis¹, A. Kamenders¹, J. Ikaunieks² and C. Rochas¹

¹Institute of Energy Systems and Environment, Faculty of Power and Electrical Engineering, Riga Technical University, Kalku street 1, LV-1658 Riga, Latvia; *Correspondence: edite.kamendere@rtu.lv 2Ekodoma Ltd., Noliktavas Street 3, LV-1010 Riga, Latvia

Abstract:

Renovation of existing buildings offers a great opportunity to reduce energy consumption, but often it also reduces indoor air quality, as buildings which were originally designed for natural ventilation are made highly air tight. A solution to the problem would be a mechanical ventilation system, but several problems are experienced when implementing it – no place for installing air ducts, cold air inflow or additional energy needed for incoming air preheating. Ventilation using heat recovery units is the one method out of many other energy saving measures. The advantage of using heat recovery units is energy saving, and as a result, savings on costs of the operation of the ventilation system. This paper describes the renovation carried out in 4-storey apartment buildings. In the course of the study, two buildings were analysed, both belonging to the series buildings of the Soviet Era (103 series), built in 1970 using the same materials, the same construction solutions. The renovation was carried out by one company, using the same materials and the same renovation principles for both buildings. The only difference after the renovation is that a new centralized mechanical ventilation system with a heat recovery unit is installed in one of the buildings, while in the second building the natural ventilation system is preserved. The arrangement of the mechanical ventilation system is rather innovative as the ventilation ducts in the building for fresh air supply are integrated into the facade’s insulation layer and enter the living room through the wall directly behind heating radiators. The main questions studied in the course of the research are the efficiency of the mechanical ventilation system heat recovery, the building’s air tightness, and the overall system efficiency.

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527-542 I. Laicāne, A. Blumberga, M. Rošā and D. Blumberga
Determinants of household electricity consumption savings: A Latvian case study
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Determinants of household electricity consumption savings: A Latvian case study

I. Laicāne*, A. Blumberga, M. Rošā and D. Blumberga

Institute of Energy Systems and Environment, Faculty of Power and Electrical Engineering, Riga Technical University, Kronvalda boulevard ¹, LV–¹0¹0 Riga, Latvia;
*Correspondence: ilze.laicane@rtu.lv

Abstract:

In order to assess the potential for energy efficiency in households it is important to understand the implications for household electricity consumption by analyzing the factors that impact consumption. Moreover some recent studies suggested that changes in household electricity consumption are more likely to be explained by user behavioural aspects than technical solutions. This paper examines the influence of household’s personal, demographic, socio–economic, the stock and use of electrical appliances, structural characteristics, external factors (such as weather, location etc.) by analysing data obtained from a smart metering pilot project currently being implemented in ⁵00 Latvian households. The preliminary results show a decrease of the electricity consumption in ²0¹³ (April–December) by ²³% for the target group and ⁵% for the control group. The aim of the study is to introduce a novel model for assessing electricity consumption and savings achieved in households. The main tasks of this study is to examine the main characteristics determining electricity consumption savings, in particular, to evaluate the extent of smart metering influence on electricity consumption savings by using linear regression model.

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335-346 I. Laicāne, A. Blumberga, M. Rosa and D. Blumberga
Assessment of changes in households’ electricity consumption
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Assessment of changes in households’ electricity consumption

I. Laicāne*, A. Blumberga, M. Rosa and D. Blumberga

Faculty of Power and Electrical Engineering, Institute of Energy Systems andEnvironment, Riga Technical University, Kronvalda bulvaris 1, LV-1010, Riga, Latvia;
*Correspondence: ilze.laicane@rtu.lv

Abstract:

The purpose of this research is based on a literature review analysis mainly based onthe evaluation of the effectiveness from the smart metering implementation as a behaviouralfeedback on the consumer daily lives and their motivations on reducing energy consumption. Afeasibility analysis of the improved household monitoring system with integrated smart metersand assessment of changes in residential electricity consumption were performed. In this study,an initial assessment of the pilot project for smart meters installation were conducted; thepreparation of the questionnaire survey for involvement of households in the pilot project weredescribed; a literature review on the factors effecting users’ behaviour were conducted; andbased on this literature review an assessment of household electricity consumption and CO2emission savings were provided. This research serves as a basis for further research to explorefactors influencing the user behaviour and to make analysis on electricity consumptionreduction in households, as well as the further development of smart metering in Latvia.

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