Cost-Optimal Sector Integration and Energy Balancing Strategies for Reaching Carbon Neutrality

Sectoral integration will play a major role in the clean energy transition to increase the utilisation rates of available renewable energy sources (RES). Preliminary studies have shown that the decarbonisation of power generation can be reached through well-developed technical solutions such as the integration of hydro, wind, and solar energy. However, emissions in the buildings, transport, and industrial sectors remain stubbornly high. Therefore, the electrification of these sectors and interconnection through smart grids have been identified as promising future development trends to avoid the usage of fossil fuels. The TIMES optimisation model is used to evaluate the future cost-effective pathways for reaching carbon neutrality in the Latvian energy sector. The model includes both the end-use sectors such as transport, buildings, industry and agriculture and the energy sector with a well-developed database of existing and future RES and storage technologies. The modelling framework allows for identifying the cost-optimal future energy mix by considering the electrification potential of each sector. Therefore, it allows analysing of the impact of different policy strategies at sectoral integration levels and the necessity for additional energy storage capacities. The preliminary results show that one of regret-free solutions for reaching the energy efficiency targets in 2030 is the wide expanse of heat pump utilisation in residential buildings instead of inefficient biomass boilers. The building heat supply transformation also brings higher power consumption and interacts with the wider utilisation of wind power. In addition, sensitivity analyses have been performed to evaluate the impact of high uncertainties related to fuel costs, resource availability and other conditions

Hygrothermal Performance Evaluation of Internally Insulated Historic Stone Building in a Cold Climate

In most cases, internal insulation is the only solution to improve the energy efficiency of historic buildings. However, it is one of the most challenging and complex energy efficiency measures due to changes in boundary conditions and hygrothermal behavior of the wall, particularly in cold climates. This study presents the long-term monitoring of the hygrothermal performance of an internally insulated historic stone wall building. The study aimed to assess the hygrothermal behavior of the dolomite wall if mineral wool insulation is applied internally on the north-east wall in the rooms with and without high internal moisture load. The measurements included temperature, relative humidity, water content, and heat flux. Monitoring results are compared with 1D hygrothermal simulations and a building energy consumption simulation. The in situ measurement results and hygrothermal assessment shows energy consumption decreased by 55% with relative humidity under the insulation staying belove 60% for most of the time, with short periods of increase over 80%. Energy consumption simulation shows an energy saving potential of up to 72% in the case of proper energy management

Solar Facade Module for Nearly Zero Energy Building. Optimization Strategies

The study presented in this paper is a continuation of small-scale passive solar wall module testing to evaluate: 1) the impact of phase change material embedded in building envelope on indoor air temperature in comparison to reference wall insulated with mineral wool 2) the impact of Fresnel lens on heat transfer processes in designed module compared to PMMA acrylic glass. Six different solar wall modules and a reference wall module were built and tested in a laboratory under controlled conditions. Compared to previous studies, changes in the experimental setup were made - solar radiation intensified, simulated outdoor temperature adjusted. The study shows explicitly the phase change melting processes in different modules tested, describing the differences between modules and impact of Fresnel lenses and insulation solutions. Room temperature with solar wall modules after the full cycle of charging and discharging latent and sensible energy (24 h) is higher than in the reference wall. Two of 3 of the proposed solar wall modules with Fresnel lens are more effective than modules with PMMA

In-Situ Moisture Assessment in External Walls of Historic Building using Non-Destructive Methods

In-situ measurements of a case study building located in Riga old town near the river Daugava has been carried out in this work. Performed measurements are moisture level of historic masonry, and interstitial monitoring of temperature and relative humidity between the layers of internal insulation and external wall. Obtained results are compared with outdoor weather data. Results show that during the cold months of the year no rising damp problem. No interstitial condensation under the internal insulation, and no risk of mold growth occur. However, the façade of the building tends to be highly influenced by the outdoor weather, and the moisture of the masonry increases during the rain load events

Laboratory Testing of Small Scale Solar Facade Module with Phase Change Material and Adjustable Insulation Layer

Active building envelopes that act as energy converters—gathering on-site available renewable energy and converting it to thermal energy or electricity—is a promising technological design niche to reduce energy consumption in the building sector, cut greenhouse gas emissions, and thus tackle climate change challenges. This research adds scientific knowledge in the field of composite building envelope structures containing phase-change materials for thermal energy storage. In this study, the focus lies on the cooling phase of the diurnal gain and release of solar energy. The experimental setup imitates day and night environment. Six alterations of small-scale solar facade modules are tested in two different configurations—with and without the adjustable insulation layer on their outer surface during the discharging phase. Modules explore combinations of aerogel, air gap, and Fresnel lenses for solar energy concentration. The results allow us to compare the impact of the application of an additional insulation layer at “night” for different designs of solar facade modules. The results show that modules with an air gap provide higher heat gains but do not take full advantage of the latent heat capacity of phase-change materials

Is the High Quality Baukultur a Monkey Wrench in the Global Climate Challenges?

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

Examining the Influence of Focal Point Location on Heat Transfer Dynamics in Phase Change Material: A Dataset Publication

Dataset including experimental data from small-scale solar facade module that consists of several components: Fresnel lens; cone-shaped air gap; aerogel (semi-transparent) as insulation layer; PCM container. Variations of the experimental settings in test setups are different cone diameter (2, 3 and 4 cm) and insulation layer thickness is (3,5 and 7cm). Nine different compositions were tested in laboratory to evaluate the ompact of focal point location. The focal point has been described with three different values that reflect its location on the inner and outer surfaces and in the middle of the PCM container. The corresponding figures can be found in the paper The Effect of Fresnel Lens Focal Point Location on Heat Transfer in Phase Change Material (PCM) Enhanced Dynamic Solar Facade. This study has been supported by Fundamental and Applied Research project ‘Smart building EnVElope with solaR Energy STorage (EVEREST)’, project No. lzp-2019/1-0363, funded by the Latvian Council of Science.Terms of use: These data are provided "as is", without any warranties of any kind. The data are provided under the Creative Commons Attribution 4.0 International license

Study of Hygrothermal Processes in External Walls with Internal Insulation

Being an important contributor to the final energy consumption, historic buildings built before 1945 have high specific heating energy consumption compared to current energy standards and norms. However, they often cannot be insulated from the outside due to their heritage and culture value. Internal insulation is an alternative. However internal insulation faces challenges related to hygrothermal behaviour leading to mold growth, freezing, deterioration and other risks. The goal of this research is to link hygrothermal simulation results with experimental results for internally insulated historic brick masonry to assess correlation between simulated and measured data as well as the most influential parameters. The study is carried out by both a mathematical simulation tool and laboratory tests of historic masonry with internal insulation with four insulation materials (mineral wool, EPS, wood fiber and granulated aerogel) in a cold climate (average 4000 heating degree days). We found disparity between measured and simulated hygrothermal performance of studied constructions due to differences in material parameters and initial conditions of materials. The latter plays a more important role than material parameters. Under a steady state of conditions, the condensate tolerating system varies between 72.7 % and 80.5 % relative humidity, but in condensate limiting systems relative humidity variates between 73.3 % and 82.3 %. The temperature between the masonry wall and all insulation materials has stabilized on average at +10 °C. Mold corresponding to Mold index 3 was discovered on wood fiber mat

Adaptation of TIMES Model Structure to Industrial, Commercial and Residential Sectors

National energy sector management differs from country to country. Therefore, it is important to develop country-specific energy models to analyse the energy demand, structure and potential policy instruments. The paper presents a pathway for adaption and improvement of the standard TIMES model structure to the specific country requirements. The analysis is based on a three-sector (industrial, commercial and residential) case study of Latvia. Literature review presents experience of other research when developing different energy models as well as adapting the TIMES model structure. The main results show a distribution of the final energy consumption and the validation of the obtained results of the sectors studied. Method and intermediate results presented in the paper are part of an ongoing modelling process of Latvia’s energy sector

Cost-Optimal Policy Strategies for Reaching Energy Efficiency Targets and Carbon Neutrality

The TIMES Latvia optimization model was developed to evaluate cost-effective pathways for reaching energy efficiency targets in 2030 and carbon neutrality in the Latvian economy by 2050. The model includes both the end-use sectors such as transport, buildings, industry and agriculture and the energy sector, with a well-developed database of existing and future RES and storage technologies. The modelling framework allows to identify the cost-optimal future energy mix by considering the electrification potential of each sector. Therefore, it allows the analysing of the impact of different policy strategies on sectoral integration levels and the necessity for additional energy storage capacities. The results show that one of the optimal solutions for reaching the energy efficiency targets in 2030 is the wide expansion of heat pump utilization merged with ambitious building renovation policy to increase energy efficiency. The building heat supply transformation also brings higher power consumption and interacts with the wider utilization of wind power. Alternative pathway could rely on increased solar power installation for self-consumption coverage which shows lower costs than building energy efficiency increase