Energy Consumption and Indoor Air Quality of Different Ventilation Possibilities in a New Apartment Building
The paper focuses on natural ventilation systems in new buildings. There is particular interest in heat energy consumption and indoor air quality with different ventilation possibilities. Indoor air quality measurements during different ventilation solutions were conducted in a new apartment building. The results of this paper show that, by applying some common ventilation solutions, the consumption of heat energy for heating the cold incoming air can reach up to 0,86 MWh/month in a 10 m2 room in the coldest months of winter.
When the renewable energy is used, the challenge is match the supply of intermittent energy with the demand for energy therefore the energy storage solutions should be used. This paper is dedicated to hydrogen accumulation from wind sources. The case study investigates the conceptual system that uses intermitted renewable energy resources to produce hydrogen (power-to-gas concept) and fuel (power-to-liquid concept). For this specific case study hydrogen is produced from surplus electricity generated by wind power plant trough electrolysis process and fuel is obtained by upgrading biogas to biomethane using hydrogen. System dynamic model is created for this conceptual system. The developed system dynamics model has been used to simulate 2 different scenarios. The results show that in both scenarios the point at which the all electricity needs of Latvia are covered is obtained. Moreover, the methodology of system dynamics used in this paper is white-box model that allows to apply the developed model to other case studies and/or to modify model based on the newest data. The developed model can be used for both scientific research and policy makers to better understand the dynamic relation within the system and the response of system to changes in both internal and external factors.
Thermal Bridge Impact on the Heating Demand in a Low-Energy House
Thermal bridges typically occur at the junction of different building components where it is difficult to achieve continuity in the thermal insulation layer. In this paper thermal bridges are investigated in the first one-family low-energy house in Latvia. The proportion of the overall heat loss due to thermal bridging is determined based on the results from a numerical calculation method described in the standard LVS EN ISO 10211 and from the simplified calculation method given in the standard LVS EN ISO 14683. In this paper the software tool THERM is used for two-dimensional thermal bridge model simulations. The results suggest that 7.7 % of the total heat transmission losses occur due to thermal bridges.
The energy efficiency – indoor air quality dilemma is well known and the main drawback to operate the mechanical ventilation is electricity costs as concluded from previous studies. Educational buildings are one of the places where future taxpayers spend a lot of time. This paper aims to study an alternative solution on how to reduce energy efficiency – indoor air quality dilemma in educational buildings by adopting systems that use renewable energy sources. A typical education building in Latvia is taken as a case study by changing it from a consumer to prosumer. This building type has a specific electricity usage profile that makes the choice of photovoltaics (PV) power quite challenging so the various power options have been analysed and used for an electricity solution. Also, the more decentralised preference is chosen – disconnect from a public heating provider and using a local system with a pellet boiler. Educational buildings using PV can reduce the electricity tariff, but the payback periods are still not very satisfactory without subsidies. The average electricity tariff per month varies between scenarios and the best one is for the scenario with 30 kW installed power. The educational building partly using 16 kW PV system reduces not only its bill for electricity but also reduces CO2 emissions by around 36 tons. The education buildings as energy prosumers using renewable energy sources are reducing GHG emissions by having high indoor air quality.
The EU 2030 climate package calls for raising energy efficiency, increasing usage of RES and decreasing the carbon footprint. There are stringent requirements for new buildings, but the energy efficiency potential in the existing building stock is still not fully explored. The latest trend in urban energy efficiency is the Positive Energy Block (PEB) strategies for new developments. It includes raising building energy efficiency, optimizing energy flow and implementing renewable energy sources (RES). Transforming all existing blocks in a city centre to a PEB would radically change the pattern of energy supply and consumption. European cities have historic centres with great architectural and cultural value. Any urban regeneration strategies must respect and preserve historic values. This paper describes double multi-criteria analysis evaluating urban blocks from both the energy efficiency and cultural heritage perspective with the goal to select the sample block for a “Smart urban regeneration – transition to the Positive Energy Block” case study. Proposed criteria for multi-criteria analysis to evaluate cultural heritage, liveability and energy efficiency potential describes specific qualities of the urban block. The obtained results show that blocks with higher cultural value show less energy efficiency potential and vice versa. It is recommended to apply cultural value and liveability qualities in the Smart urban regeneration process to those blocks with high energy efficiency potential.
The paper describes the development of a computer-based inverse model for climate adaptive building shell which is in the cold climatic conditions of Latvia to determine changes in energy consumption. Types, principles of operation and classification of climate adaptive building shells (CABS) were reviewed and CABS most fitting to Latvia’s climate conditions were chosen for application in the model. Research implies that building modelling tools play an important role in the design phase. The results indicate that hourly facade adjustment can have a significant impact on GHG emissions and energy consumption reduction without compromising the comfort level. Optimization is proven to be an essential part of the inverse modelling phase, which provides the best possible option defined by the user for the characteristics that distinguish climate adaptive building shells. Inverse modelling approach allowed to determine necessary building enclosure parameters that need to be met to provide best performance.
The study presented in this paper is a continued research of preceding tests of small-scale passive solar wall module to explore 1) the behaviour of solar wall module in various setups for an extended 48-hour period of time, and 2) the performance of solar module with and without fine metal wires as heat exchange enhancers. Eight different solar wall module setups were assembled and tested in a precisely controlled environment. The study reassures observations and conclusions made in previous research and provides new conclusions. Modules that can harvest more solar radiation in the charging phase are exposed to higher heat losses at the discharge phase to the external environment. Module setups that reach stable heat flow fast and respectively melt PCM volume effectively, create a problem of not managing to harvest more of the available solar radiation.
Bioeconomy in Europe has become one of the leading courses for sustainable and resource-efficient development. Main aspects of bioeconomy: development of new technologies and processes, development of markets and competitiveness for bioeconomy can be implemented through higher education and transformative knowledge for building a sustainable bioeconomy. Over the past year, new bioeconomy-related Master study programmes have been created and have integrated bioeconomy goals into their research, programme aims and learning outcomes. During the research the set of competences based on sustainable development competences and bioeconomy competences have been created. The integration of competences for bioeconomy development in higher education can be seen as an important step in transformation towards knowledge-based bioeconomy. On this basis, 10 Master study programmes across Europe were analysed in order to find out the actual integration of competences in different study programmes for bioeconomy. Results of the analysis show that transdisciplinary competence, learning competence, interdisciplinary competence and system-thinking competence are strongly integrated into the study programmes. The analysis also shows that the integration of other competences, like anticipatory competence, normative competence, strategic competence and interpersonal competence can be improved in the future.
Increased energy efficiency of the building sector is high on the list of priorities for energy policy since better energy efficiency would help to reduce impact on climate change and increase security of energy supply. One aim of the present study was to find a relative effect of growth of demand for energy services due to changes in income, energy consumption per unit of demand due to technological development, changes in electricity price and household income on household electricity consumption in Latvia. The method applied included system dynamics modeling and data from a household survey regarding the relationship between electricity saving activities and the electricity cost-income ratio. The results revealed that, in direct contrast to the expected, a potential reduction of the electricity consumption is rather insensitive to electricity price and electricity cost-income ratio, and that the efficiency of technologies could be the main drivers for future electricity savings. The results suggest that support to advancement of technologies and faster replacement of inefficient ones rather than influencing the energy price could be effective energy policy measures. The model, developed in the study could be used in similar assessments in other countries.
The European Union has set the target for energy sector decarbonization. Variable renewable energy technologies are necessary to reach this target, but a high level of variable renewable energy raises the flexibility issues. In this research paper, the flexibility issue is addressed by analysing possibility of sector coupling via power-to-heat and power-to-gas applications by using system dynamics approach. The model is applied to the case of Latvia. Model results show that power-to-heat is a viable flexibility measure, and with additional financial incentives, it can even help to move towards decarbonization of the energy sector. In the best scenario, heat from surplus power can cover 37 % from total heat production in 2050. Unfortunately, in spite of a well-developed gas infrastructure, power-to-gas application is still very immature, and, in the best-case scenario with high incentives in power-to-gas technologies, only 7 % from available power surplus could be allocated for power-to-gas technologies in 2050.