scholarly journals Dynamic Approach to Evaluate the Effect of Reducing District Heating Temperature on Indoor Thermal Comfort

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 25
Author(s):  
Benedetta Grassi ◽  
Edoardo Alessio Piana ◽  
Gian Paolo Beretta ◽  
Mariagrazia Pilotelli
Keyword(s):  
Heat Exchanger ◽  
Thermal Comfort ◽  
Urban Areas ◽  
Heating Temperature ◽  
Renewable Energy Sources ◽  
District Heating ◽  
Energy Performance ◽  
Building Stock ◽  
The Individual ◽  
High Temperature Operation

To reduce energy consumption for space heating, a coordinated action on energy supply, building fabric and occupant behavior is required to realize sustainable improvements. A reduction in district heating supply temperature is an interesting option to allow the incorporation of renewable energy sources and reduce distribution losses, but its impact on the final users must be considered. This aspect is especially critical as most European countries feature an old building stock, with poor insulation and heating systems designed for high-temperature operation. In this study, a complete methodology is devised to evaluate the effect of district heating temperature reduction on the end users by modeling all the stages of the system, from the primary heat exchanger to the indoor environment. A dynamic energy performance engine, based on EN ISO 52016-1:2017 standard and completed with a heat exchanger model, is implemented, and its outputs are used to calculate thermal comfort indicators throughout the heating season. As a practical application, the method is used to evaluate different scenarios resulting from the reduction of primary supply temperature of a second-generation district heating network in Northern Italy. Several building typologies dating back to different periods are considered, in the conservative assumption of radiator heating. The results of the simulations show that the most severe discomfort situations are experienced in buildings built before 1990, but in recent buildings the amount of discomfort occurrences can be high because of the poor output of radiators when working at very low temperatures. Among the possible measures that could help the transition, actions on the primary side, on the installed power and on the building fabric are considered. The investigation method requires a limited amount of input data and is applicable to different scales, from the individual building to entire urban areas lined up for renovation.

scholarly journals Building Integrated Shading and Building Applied Photovoltaic System Assessment in the Energy Performance and Thermal Comfort of Office Buildings

2018 ◽  
Vol 10 (12) ◽  
pp. 4670 ◽  
Author(s):  
Georgios Martinopoulos ◽  
Anna Serasidou ◽  
Panagiota Antoniadou ◽  
Agis M. Papadopoulos
Keyword(s):  
Energy Consumption ◽  
Thermal Comfort ◽  
Urban Areas ◽  
Specific Energy Consumption ◽  
Energy Performance ◽  
Office Buildings ◽  
Photovoltaic System ◽  
Energy Status ◽  
Building Stock ◽  
Consumption Rates

Non-residential and more specifically office buildings are, nowadays, an integral part of the building stock and milestones of urban areas in most of the developed and developing countries all over the world. Compared to other building types, office buildings present some of the highest specific energy consumption rates. In the present study, a typical nine-story office is assessed for a number of different building integrated retrofitting measures. Measurements of indoor environmental conditions were used in order to validate the developed simulation model of the building in EnergyPlus. Then, a number of different building integration options for photovoltaic systems and shading options are examined, in order to evaluate the best option in terms of indoor air quality, thermal comfort and energy consumption. The amount of electricity produced can meet 65% of the building’s annual electricity requirements, while the shading options can reduce energy requirements by as much as 33%. Although this in not a value that can be dismissed easily, it becomes clear that further—and more deeply aiming—measures are needed, if the building is to achieve near zero energy status.

scholarly journals Experimental Data and Simulations of Performance and Thermal Comfort in a Typical Mediterranean House

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3311
Author(s):  
Víctor Pérez-Andreu ◽  
Carolina Aparicio-Fernández ◽  
José-Luis Vivancos ◽  
Javier Cárcel-Carrasco
Keyword(s):  
Energy Efficiency ◽  
Thermal Comfort ◽  
Energy Demand ◽  
Natural Ventilation ◽  
Thermal Characterization ◽  
Energy Performance ◽  
Building Stock ◽  
Energy Demands ◽  
Dwelling House ◽  
Account Standard

The number of buildings renovated following the introduction of European energy-efficiency policy represents a small number of buildings in Spain. So, the main Spanish building stock needs an urgent energy renovation. Using passive strategies is essential, and thermal characterization and predictive tests of the energy-efficiency improvements achieving acceptable levels of comfort for their users are urgently necessary. This study analyzes the energy performance and thermal comfort of the users in a typical Mediterranean dwelling house. A transient simulation has been used to acquire the scope of Spanish standards for its energy rehabilitation, taking into account standard comfort conditions. The work is based on thermal monitoring of the building and a numerical validated model developed in TRNSYS. Energy demands for different models have been calculated considering different passive constructive measures combined with real wind site conditions and the behavior of users related to natural ventilation. This methodology has given us the necessary information to decide the best solution in relation to energy demand and facility of implementation. The thermal comfort for different models is not directly related to energy demand and has allowed checking when and where the measures need to be done.

scholarly journals Energy Rehabilitation of Social Housing in Vulnerable Areas. Case study: a 1950s Building in a Medium-sized Mediterranean City

2019 ◽  
Vol 4 (1) ◽  
pp. 44
Author(s):  
Ruá María José ◽  
Huedo Patricia ◽  
Cabeza Manuel ◽  
Saez Beatriz ◽  
Civera Vicente
Keyword(s):  
Low Income ◽  
Social Housing ◽  
Urban Areas ◽  
Optimal Solution ◽  
Energy Performance ◽  
Urban Context ◽  
Building Stock ◽  
Performance Simulation ◽  
Urban Level

In the urban context, buildings play a key role as they are energy consumers. In well-established cities with a high percentage of aged building stock, the focus should lie on sensitive urban areas where the weakest population sectors and the worst physico-economic conditions are usually encountered. In this work, the energy refurbishment of social housing is proposed. A block of municipally owned buildings is selected as a case study to consider that public buildings play an exemplary role according to Directive 2012/27/EU. The group is formed by 12 buildings, which account for 120 dwellings.This study is grounded on two levels. First the urban level. The building is located in a prioritised urban Area of Rehabilitation, Renovation and Urban Regeneration (ARRU), according to the new local Land Plan. This area presents multidimensional vulnerability and considers urban, building, socio-demographic and socio-economic features. Second, the building presents very low energy performance. It was built in 1959 when a high demand of dwellings and the economic resources then available led to low-quality buildings that are far from meeting today’s standards.Some proposals are made, having in mind the specific features of the urban context. The energy refurbishment of the building is proposed, selecting the optimal solution, considering technical, environmental and economic criteria. The energy performance simulation shows a remarkable improvement of the energy performance, resulting in an improvement of the thermal comfort of the dwellers. Besides, a reduction in the energy consumption is reached, which would reduce the energy bills and, on the other hand, a reduction of the carbon emissions to the atmosphere, contributing to a better environment quality. Having in mind that the building is intended for social housing, energy poverty situations could be avoided, as dwellings are inhabited by low-income dwellers.

scholarly journals Towards Nearly-Zero Energy in Heritage Residential Buildings Retrofitting in Hot, Dry Climates

2021 ◽  
Vol 13 (24) ◽  
pp. 13934
Author(s):  
Hanan S. S. Ibrahim ◽  
Ahmed Z. Khan ◽  
Yehya Serag ◽  
Shady Attia
Keyword(s):  
Renewable Energy ◽  
Residential Buildings ◽  
Renewable Energy Sources ◽  
Energy Performance ◽  
High Energy ◽  
Energy Sources ◽  
Zero Energy ◽  
Building Stock ◽  
Heritage Buildings ◽  
Dry Climates

Retrofitting “nearly-zero energy” heritage buildings has always been controversial, due to the usual association of the “nearly-zero energy” target with high energy performance and the utilization of renewable energy sources in highly regarded cultural values of heritage buildings. This paper aims to evaluate the potential of turning heritage building stock into a “nearly-zero energy” in hot, dry climates, which has been addressed in only a few studies. Therefore, a four-phase integrated energy retrofitting methodology was proposed and applied to a sample of heritage residential building stock in Egypt along with microscale analysis on buildings. Three reference buildings were selected, representing the most dominant building typologies. The study combines field measurements and observations with energy simulations. In addition, simulation models were created and calibrated based on monitored data in the reference buildings. The results show that the application of hybrid passive and active non-energy generating scenarios significantly impacts energy use in the reference buildings, e.g., where 66.4% of annual electricity use can be saved. Moreover, the application of solar energy sources approximately covers the energy demand in the reference buildings, e.g., where an annual self-consumption of electricity up to 78% and surplus electricity up to 20.4% can be achieved by using photo-voltaic modules. Furthermore, annual natural gas of up to 66.8% can be saved by using two unglazed solar collectors. Lastly, achieving “nearly-zero energy” was possible for the presented case study area. The originality of this work lies in developing and applying an informed retrofitting (nearly-zero energy) guide to be used as a benchmark energy model for buildings that belong to an important historical era. The findings contribute to fill a gap in existing studies of integrating renewable energy sources to achieve “nearly-zero energy” in heritage buildings in hot climates.

scholarly journals Potentials for improving energy performance of multifamily housing blocks connected to the district heating system

2018 ◽  
Vol 22 (Suppl. 4) ◽  
pp. 1183-1193
Author(s):  
Natasa Cukovic-Ignjatovic ◽  
Dusan Ignjatovic ◽  
Budimir Sudimac
Keyword(s):  
Housing Stock ◽  
Renewable Energy Sources ◽  
District Heating ◽  
Building Design ◽  
Heating System ◽  
Energy Performance ◽  
District Level ◽  
Multifamily Housing ◽  
Open Spaces ◽  
District Heating System

Developments conceived following the principles of Athens Charter were typical form of urban answer to the post-war housing shortage and during the decades of intense construction activity that followed. In city of Belgrade, multifamily housing in open city blocks built between 1961 and 1990 account for about 40% of current housing stock. The current ownership and operation of these housing blocks derive from their socialist legacy: home-owners rights relate only to the buildings, excluding any open spaces, even the ones immediately along the building?s perimeter. On the other hand, heating is supplied by district heating system. Management of open spaces as well as provision of district heating are subordinates to local municipality (the city of Belgrade). Energy efficiency related refurbishment options for these developments that would engage both the home-owners and the public companies may be the key for bringing ever-needed modernization, prolonged lifespan and a sustainable way of using this portion of housing stock. By applying simple architectural measures, energy demand for heating of these buildings can be reduced by 30-78%, which opens a pathway for effective use of renewable energy sources. Unlike solar energy, which can be managed at building level, geothermal energy can be exploited only at the district level due to the ownership rights. The presented research explores the effectiveness of using geo-thermal energy at a district level coupled with systematic approach to building refurbishment, taking the advantage of the repetitive use of the same building design and the formal and practical relations with local authorities.

scholarly journals District Power-To-Heat/Cool Complemented by Sewage Heat Recovery

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 364 ◽  
Author(s):  
Marcello Aprile ◽  
Rossano Scoccia ◽  
Alice Dénarié ◽  
Pál Kiss ◽  
Marcell Dombrovszky ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Heat Pump ◽  
Heat Recovery ◽  
Renewable Energy Sources ◽  
District Heating ◽  
Heat Pumps ◽  
Economic Feasibility ◽  
Operational Experience ◽  
Operational Parameters ◽  
Heating And Cooling

District heating and cooling (DHC), when combined with waste or renewable energy sources, is an environmentally sound alternative to individual heating and cooling systems in buildings. In this work, the theoretical energy and economic performances of a DHC network complemented by compression heat pump and sewage heat exchanger are assessed through dynamic, year-round energy simulations. The proposed system comprises also a water storage and a PV plant. The study stems from the operational experience on a DHC network in Budapest, in which a new sewage heat recovery system is in place and provided the experimental base for assessing main operational parameters of the sewage heat exchanger, like effectiveness, parasitic energy consumption and impact of cleaning. The energy and economic potential is explored for a commercial district in Italy. It is found that the overall seasonal COP and EER are 3.10 and 3.64, while the seasonal COP and EER of the heat pump alone achieve 3.74 and 4.03, respectively. The economic feasibility is investigated by means of the levelized cost of heating and cooling (LCOHC). With an overall LCOHC between 79.1 and 89.9 €/MWh, the proposed system can be an attractive solution with respect to individual heat pumps.

scholarly journals Building stock simulation to support the development of a district multi-energy grid

2019 ◽  
Vol 111 ◽  
pp. 06027
Author(s):  
Francesco Causone ◽  
Martina Pelle
Keyword(s):  
Urban Areas ◽  
Cooling System ◽  
Residential Buildings ◽  
Energy Performance ◽  
Heat Pumps ◽  
Monitoring Data ◽  
Building Stock ◽  
District Heating System ◽  
Existing Building ◽  
Energy Grid

The urbanization process is constantly increasing worldwide. Today over 50 % of the population resides in urban areas and this value is expected to grow up to 68 % by 2050. In this scenario, the development of district scale energy grids and management systems has become crucial to optimize energy use and to balance energy flows within the cities, encouraging the use of renewable sources and self-consumption. This study focusses on a district under development in the city of Milan, involving an urban area of about 920 000 m2, which, once completed, will count for about 4 500 apartments, a school and a few other commercial uses. The existing energy systems consist of an electric grid, including a small photovoltaic field, a district heating system and a local district cooling system exploiting groundwater via heat pumps. They serve, at present, seven residential tower buildings (400 apartments). The overarching aim of the research is to evolve the existing grid into a smart energy grid able to guarantee an intelligent management of the district, empowering eventually people to apply for demand-response schemes, electric mobility and other innovative services. In order to perform such an improvement and extension of the exiting grid, it is necessary to evaluate and simulate the profiles and dynamics of the final energy uses for the residential buildings, that will represent the major load on site. Since monitoring data are not yet available for the district, the evaluation of the energy performance of the existing buildings has been developed through dynamic energy simulations via the definition of profile loads of the most frequent apartment typologies, that allow, moreover, to simulate further developments in the districts. Besides, a monitoring plan for the existing systems has been developed and implemented. Monitoring data will be used at first for validating the developed load profiles; then, they will be analysed to develop optimisation algorithms for the management of the upgraded energy grid. In this paper, the case study is presented and the results of the analysis, via energy simulation, on the existing building stock are reported.

scholarly journals Cooling Degree Models and Future Energy Demand in the Residential Sector. A Seven-Country Case Study

2021 ◽  
Vol 13 (5) ◽  
pp. 2987
Author(s):  
Raúl Castaño-Rosa ◽  
Roberto Barrella ◽  
Carmen Sánchez-Guevara ◽  
Ricardo Barbosa ◽  
Ioanna Kyprianou ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Thermal Comfort ◽  
Energy Demand ◽  
Energy Performance ◽  
Low Energy ◽  
Extreme Weather Events ◽  
Building Stock ◽  
Residential Sector ◽  
Adaptive Thermal Comfort

The intensity and duration of hot weather and the number of extreme weather events, such as heatwaves, are increasing, leading to a growing need for space cooling energy demand. Together with the building stock’s low energy performance, this phenomenon may also increase households’ energy consumption. On the other hand, the low level of ownership of cooling equipment can cause low energy consumption, leading to a lack of indoor thermal comfort and several health-related problems, yet increasing the risk of energy poverty in summer. Understanding future temperature variations and the associated impacts on building cooling demand will allow mitigating future issues related to a warmer climate. In this respect, this paper analyses the effects of change in temperatures in the residential sector cooling demand in 2050 for a case study of nineteen cities across seven countries: Cyprus, Finland, Greece, Israel, Portugal, Slovakia, and Spain, by estimating cooling degree days and hours (CDD and CDH). CDD and CDH are calculated using both fixed and adaptive thermal comfort temperature thresholds for 2020 and 2050, understanding their strengths and weaknesses to assess the effects of warmer temperatures. Results suggest a noticeable average increase in CDD and CDH values, up to double, by using both thresholds for 2050, with a particular interest in northern countries where structural modifications in the building stock and occupants’ behavior should be anticipated. Furthermore, the use of the adaptive thermal comfort threshold shows that the projected temperature increases for 2050 might affect people’s capability to adapt their comfort band (i.e., indoor habitability) as temperatures would be higher than the maximum admissible values for people’s comfort and health.

scholarly journals The Influence of Immediate Urban Surroundings on Energy Performance of Historical Buildings

10.29007/ghfx ◽  
2020 ◽  
Author(s):  
Onur Dursun ◽  
Feyza Durmuslar ◽  
Duhan Olmez
Keyword(s):  
Urban Areas ◽  
Energy Demand ◽  
Energy Performance ◽  
Building Envelope ◽  
Historical Buildings ◽  
Humid Climate ◽  
Numerical Result ◽  
The Individual ◽  
Hot Humid Climate ◽  
Thermal Simulations

High-density urban areas contain large number of historical buildings whose structures and artistic values are protected by regulations. This restricts the improvements can be made to building envelope to reduce energy demand of historical buildings. Therefore, immediate urban surroundings (IUS) may play a central role on energy performance of historical buildings (EPHB). Yet, literature has provided little or no evidence, so far. To address the gap, the current experimental inquiry aims to test the significance of IUS’s influence on the EPHB. To achieve, historical structure in hot- humid climate was selected and surveyed thoroughly. Control and intervention cases were considered to measure the influence IUS. The control case corresponds to the former state of IUS; whereas the intervention described as the IUS which includes a recently built office block with reflective glass façade. The numerical result obtained from computational thermal simulations were used for comparison. Accordingly, the increase in heating demand substantially surpassed the decrease in cooling demand for the case under study. Therefore, a significant increase in total energy demand was observed in the presence of intervention. In addition, the energy performance of the individual volumes located in the lower floors presented higher fluctuations due to intervention’s shading effect.

Energy Consumption and CO2 Emission of Buildings Built with Industrialized Technology: The Case of Debrecen and Future Trends

2014 ◽  
Vol 899 ◽  
pp. 16-23
Author(s):  
Tamás Csoknyai
Keyword(s):  
Energy Consumption ◽  
Residential Buildings ◽  
District Heating ◽  
Energy Performance ◽  
Future Trend ◽  
Building Stock ◽  
Heating Systems ◽  
Heat Demand ◽  
District Heating Systems ◽  
Inefficient Operation

The residential buildings built with prefabricated technology (also called panel buildings) represent a significant part of the building stock, particularly in Eastern Europe. These buildings are typically 30-40 years old and due to their poor energy performance they have been in the focus of energy policy makers over the recent years. These buildings are typically connected to district heating systems and the continuously decreasing heat demand caused by the renovation subsidy programs resulting in risks of inefficient operation and on the long term it questions the viability of the district heating systems. Therefore it is particularly important to have a clear picture on the energy consumption trends about this segment of the building stock. In this paper, the building stock of the city of Debrecen connected to district heating is analysed. The current energy consumption figures of the buildings are analysed. In Debrecen, the share of retrofitted buildings is relatively low (appr. 15%), therefore a future trend analysis was also carried out. The results of this study can be interesting for other cities as well, particularly those with a significant share of “panel buildings”.

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