On calculated and actual energy savings from thermal building renovations – Long term field evaluation of multifamily buildings (original) (raw)
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System impact of energy efficient building refurbishment within a district heated region
Energy, 2016
The energy efficiency of the European building stock needs to be increased in order to fulfill the climate goals of the European Union. To be able to evaluate the impact of energy efficient refurbishment in matters of greenhouse gas emissions, it is necessary to apply a system perspective where not only the building but also the surrounding energy system is taken into consideration. This study examines the impact that energy efficient refurbishment of multi-family buildings has on the district heating and the electricity production. It also investigates the impact on electricity utilization and emissions of greenhouse gases. The results from the simulation of four energy efficiency building refurbishment packages were used to evaluate the impact on the district heating system. The packages were chosen to show the difference between refurbishment actions that increase the use of electricity when lowering the heat demand, and actions that lower the heat demand without increasing the electricity use. The energy system cost optimization modeling tool MODEST (Model for Optimization of Dynamic Energy Systems with Time-Dependent Components and Boundary Conditions) was used. When comparing two refurbishment packages with the same annual district heating use, this study shows that a package including changes in the building envelope decreases the greenhouse gas emissions more than a package including ventilation measures.
Case Study on Residential Building Renovation and its Impact on the Energy Use and Thermal Comfort
Energy Procedia, 2014
In Norway, a large portion of the building stock originates from the period from 1955 to 1990. Many of these buildings fail to comply with the current building regulations regarding the energy consumption. In this study, the possibility for upgrading a hypothetical apartment building with an oil-based heating system has been investigated employing simulations from the IDA Indoor Climate and Energy software. For the construction of the original building, customs and regulations from the period 1981-90 were employed, and the building envelope was upgraded to the requirements of the Norwegian research centre on Zero Emission Buildings. Two alternative heating systems have been investigated: solar thermal collectors (i) alone and (ii) as combined with borehole thermal storage and a ground-source heat pump. For each case, the energy consumption, thermal comfort and indoor climate were studied. The simulations predict a reduction in the total annual heat demand to one third of the original with the upgrading. For the alternative heating systems, with solar collectors alone the demand for additional electric heating was still considerable, however in the combined system it was negligible. Regarding thermal comfort, in the upgraded building longer periods with elevated temperatures were observed.
Primary energy has grown by 49% worldwide in the last two decades. The residential building stock in Germany accounts for about one third of the total energy demand of the country. About 90% of this building stock is existing and not consistent with current standards in the context of the German Energy Saving Ordinance (EnEV) 2009. Consequently, refurbishment of the existing residential buildings supports significant opportunities to improve their energy performance. However, most refurbishment measures in Germany are limited to windows replacement and roof and upper floor(s) insulation. This paper investigates an integrative approach for thermal refurbishment measures of the whole building envelope and heating system in terms of three scenarios to two case study buildings: timber frame and modern buildings in Wolfhagen, Germany. Thus, the study aims at reducing the buildings’ heat losses and saving the heating and primary energy demands. The results show a great potential for saving the case study buildings’ specific annual heating energy demand by about 48%, 41%, 45% and 46%, 44% in each scenario for the timber frame building and modern buildings respectively in comparison to the previously estimated baseline values. A small difference in heating demand savings between the scenarios of each building is noticed. Hence, it can be interpreted that the basement ceiling is not a refurbishment priority while the façade has to be taken into account for refurbishment. Other considerations affecting primary and heating demands have to be studied while not all refurbishment scenarios possibilities are worked out in this paper. Keywords: Energy Demand, Existing Residential Buildings, Refurbishment, Integrative, Scenarios
Energy savings and carbon reduction due to renovated buildings
International Review of Mechanical Engineering
The paper deals with an energy saving case study of a renovated building in comparison with the building energy balance before renovation. The renovation was carried out in the building envelopes such as external walls, floor on ground and the flat roof for the improvement of thermal insulation properties of the investigated building. The renovation has brought forward energy saving effects, which are important for both reducing energy consumption for heating during winter seasons and the associated heating costs. In addition, the renovation represents a positive environmental impact due to the reduction of carbon dioxide emissions from such dwellings. The energy renovation of the case study building evaluated was used as a base for an estimation of energy savings and reductions of carbon emissions within a housing estate residential complex with twenty similar buildings. The study presents the importance of having such thermally insulated building envelopes in building together with windows that also have good thermal property and insulation quality for the reduction of overall energy consumption.
Buildings
To achieve carbon neutrality in the EU, it is important to renovate the existing EU residential buildings for a higher building energy efficiency. This study examines the impacts of several novel renovation technologies on energy consumption, CO2 emissions and indoor climates in southern European residential buildings through building-level simulations. Three typical residential buildings in South Europe were chosen as the demo buildings to implement the novel technologies. The technologies were classified into passive, ventilation and generation packages, and then simulated independently under the intermittent and continuous heating schedules. Additionally, two final combinations of renovation technologies were also simulated to demonstrate the maximum energy and CO2 emissions reduction potential of the demo buildings. All novel retrofit technologies manifested obvious effects on the energy consumption and CO2 emissions. Nevertheless, the effects were significantly affected by the ...
Sustainable Cities and Society, 2021
Renovation at district scale is a key strategy to reduce CO 2 emissions and energy consumptions by optimising the implementation of renewable energy sources and taking advantage of economies of scale. In this context, this paper focuses on assessing the positive impacts and difficulties after the energy rehabilitation of thermal envelopes in two buildings that belong to two different District Heating systems. The methodology is based on the comparative analysis of indoor temperatures data and energy consumption data of 17 monitored dwellings. The results showed a significant association between the improvement of envelopes and the increase of indoor temperatures in winter (β=0,644). Due to some technical and social barriers, the heating system was not regulated after the rehabilitation, so energy consumption was unnecessarily high, there were situations of indoor overheating in winter (maximum average indoor temperatures between 24-26 • C) and these issues produced dissatisfaction on neighbours. In order to avoid these negative consequences, some recommendations are provided, such as informing neighbours about expectations in each step of the long rehabilitation process, reconsidering payments to promote the envelope rehabilitation but maintaining a fixed cost to protect vulnerable groups, and promoting post-occupational studies that contribute to the viability and update of this kind of District Heating systems.
Sustainability
In Sweden, 90% of multifamily buildings utilize district heat and a large portion is in need of renovation. The aim is to analyze the impact of renovating a multifamily building stock in a district heating and cooling system, in terms of primary energy savings, peak power demands, electricity demand and production, and greenhouse gas emissions on local and global levels. The study analyzes scenarios regarding measures on the building envelope, ventilation, and substitution from district heat to ground source heat pump. The results indicate improved energy performance for all scenarios, ranging from 11% to 56%. Moreover, the scenarios present a reduction of fossil fuel use and reduced peak power demand in the district heating and cooling system ranging from 1 MW to 13 MW, corresponding to 4–48 W/m2 heated building area. However, the study concludes that scenarios including a ground source heat pump generate significantly higher global greenhouse gas emissions relative to scenarios in...
Environmental impact of energy refurbishment of buildings within different district heating systems
Applied Energy, 2017
h i g h l i g h t s Energy refurbishment of a multi-family house within a district heating system. Changes in purchased energy, primary energy use and CO 2 emissions are analyzed. Four energy refurbishment packages and four district heating systems are included. Purchased energy savings are not correlated to the change in environmental impact. It is more important to reduce electricity use than heating demand.
The Influence of Energy Renovation on the Change of Indoor Temperature and Energy Use
Energies
The aim of the renovation of apartment buildings is to lower the energy consumption of those buildings, mainly the heating energy consumption. There are few analyses regarding those other energy consumptions which are also related to the primary energy need for calculating the energy efficiency class, including the primary energy need of calculated heating, domestic hot water (DHW), and household electricity. Indoor temperature is directly connected with heating energy consumption, but it is not known yet how much it will change after renovation. One of the research issues relates to the change of electricity and DHW usage after renovation and to the question of whether this change is related to the users’ behavior or to changes to technical solutions. Thirty-five renovated apartment buildings have been analyzed in this study, where the data of indoor temperature, airflow, and energy consumption for DHW with and without circulation and electricity use in apartments and common rooms ...