scholarly journals A Staged Approach for Energy Retrofitting an Old Service Building: A Cost-Optimal Assessment

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6929
Author(s):  
Jorge Lopes ◽  
Rui A. F. Oliveira ◽  
Nerija Banaitiene ◽  
Audrius Banaitis
Keyword(s):  
Discount Rate ◽  
Age Groups ◽  
Energy Performance ◽  
Building Envelope ◽  
Hot Water ◽  
Office Buildings ◽  
Future Research ◽  
Financial Evaluation ◽  
Financial Return ◽  
The Real

Office buildings built before the pre-1960 age constitute a relevant group for analyzing the energy performance of the Portuguese building sector. A dynamic energy simulation was used to assess the energy performance of an existing office building located in the town of Bragança, Portugal. By using a staged renovation approach, two passive technologies applied to the building envelope and an efficient domestic hot water system were selected and a financial evaluation through the net saving (NS) method was undertaken to choose the best efficiency measures/packages for improving the building’s energy performance. Real discount rates of 3% and 1% were used in the financial evaluation. Considering the real discount rate of 3%, the results showed that only two out seven retrofit options had a positive financial return. By using the real discount rate of 1%, all retrofit options were found to be financially efficient. The results of the study corroborated those of earlier works that found that the financial profitability of energy renovation investments is very sensitive to the discount rate used in the analysis. The results of the study also suggested that the staged renovation approach used in the analysis is economically feasible, and that this approach is an alternative to one-step renovation approach to help to achieve the country´s energy and climate targets by 2030. Suggestions for future research conducted for office buildings in the different climate zones and other age groups in Portugal are proposed.

scholarly journals EVALUATION OF COST-OPTIMAL RETROFIT INVESTMENT IN BUILDINGS: THE CASE OF BRAGANÇA FIRE STATION, PORTUGAL

2021 ◽  
Vol 25 (5) ◽  
pp. 369-381
Author(s):  
Sónia Cova ◽  
Carlos Andrade ◽  
Orlando Soares ◽  
Jorge Lopes
Keyword(s):  
Water System ◽  
Cost Effective ◽  
Energy Performance ◽  
Hot Water ◽  
Office Buildings ◽  
Financial Return ◽  
Building Retrofit ◽  
Efficiency Measures ◽  
Cost Effective Approach ◽  
The Cost

Office buildings built before the entry into force of the first thermal regulation in 1991 constitute a relevant group for analysing the energy performance of the Portuguese building sector. A dynamic energy simulation was used to assess the energy performance of an existing office building located in the town of Bragança, Portugal. Four energy efficiency measures were selected and a financial evaluation through the internal rate of return (IRR) method was undertaken to choose the best retrofit option for improving the building’s energy performance. An investment package consisting of the roof insulation and a new equipment for the domestic hot water system presented an IRR higher than the discount rate used in the analysis, and, thus, a positive financial return. The results of the study also suggest that the EU’s comparative methodology framework is not particularly suitable for assessing building retrofit investment at the private investor’s perspective and further refinement in the cost-effective approach to renovations is needed to help stimulate building’s energy renovation market. Suggestions for further studies conducted for office buildings in the different climate zones in Portugal are also proposed.

scholarly journals A Comparative Study: Energy Performance Analysis of Conventional Office Buildings at Lucknow

2020 ◽  
Vol 20 (1) ◽  
pp. 24-34
Author(s):  
Farheen Bano ◽  
Vandana Sehgal
Keyword(s):  
Energy Consumption ◽  
Time Use ◽  
Energy Savings ◽  
Energy Performance ◽  
Building Envelope ◽  
Office Buildings ◽  
Energy Audit ◽  
Energy Usage ◽  
Factors Affecting ◽  
Using Data

In this study, the energy consumption of three government and three private office buildings in Lucknow was investigated, and the energy performance index (EPI) for each building was determined. The main purpose of this research was to assess the energy usage of the buildings and identify factors affecting the energy usage. An analysis was performed using data from an energy audit of government buildings, electricity bills of private office buildings, and an on-site visit to determine building envelope materials and its systems. The annual energy consumption of buildings has been evaluated through EPI. The EPI, measured in kilowatt hour per square meter per year, is annual energy consumption in kilowatt hours divided by the gross floor area of the building in square meters. In this study, the energy benchmark for day-time-use office buildings in composite climate specified by Energy Conservation Building Code (ECBC) has been compared with the energy consumption of the selected buildings. Consequently, it has been found that the average EPI of the selected buildings was close to the national energy benchmark indicated by ECBC. Moreover, factors causing inefficient energy consumption were determined, and solutions for consistent energy savings are suggested for buildings in composite climate.

scholarly journals New Equation for Optimal Insulation Dependency on the Climate for Office Buildings

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 321
Author(s):  
Kaiser Ahmed ◽  
Jarek Kurnitski
Keyword(s):  
Energy Performance ◽  
Building Envelope ◽  
Cold Climate ◽  
Office Buildings ◽  
Sensitivity Analyses ◽  
Base Temperature ◽  
Optimal Solutions ◽  
U Value ◽  
New Equation ◽  
Different Climates

The comparison of building energy efficiency in different climates is a growing issue. Unique structural solutions will not ensure the same energy use, but the differences also remain if cost-optimal solutions are applied. This study developed a new equation for the assessment of building envelope optimal insulation in different climates for office buildings. The developed method suggests determining actual degree days from simulated heating energy need and the thermal conductance of a building, avoiding in such a way the use of a base temperature. The method was tested in four climates and validated against cost-optimal solutions solved with optimization. The accuracy of the method was assessed with sensitivity analyses of key parameters such as window-to-wall ratios (WWRs), window g-values, costs of heating, and electricity. These results showed that the existing square root equation overestimated the climate difference effect so that the calculation from the cold climate U-value resulted in less insulation than cost-optimal in warmer climates. Parametric analyses revealed that the power value of 0.2 remarkably improved the accuracy as well as performance worked well in all cases and can be recommended as a default value. Sensitivity analyses with a broad range of energy costs and window parameters revealed that the developed equation resulted in maximum 5% underestimation and maximum 7% overestimation of an average area-weighted optimal U-value of building envelope in another climate. The developed method allows objectively to compare optimal insulation of the building envelope in different climates. The method is easy to apply for energy performance comparison of similar buildings in different climates and also for energy performance requirements comparison.

scholarly journals Analysis of the Impact of the Fireplace Heating on the Energy Performance of the Family House

2020 ◽  
Vol 64 (2) ◽  
pp. 145-149
Author(s):  
Rastislav Ingeli ◽  
Peter Buday
Keyword(s):  
Energy Efficient ◽  
Energy Use ◽  
Energy Performance ◽  
Building Envelope ◽  
Cold Climate ◽  
Hot Water ◽  
Energy Class ◽  
Main Concern ◽  
Technical Equipment ◽  
The Impact

Reduction of energy use in buildings is an important measure to achieve climate changes of mitigation. It is essential to minimize heat losses when designing energy efficient buildings. For energy efficient building in a cold climate, a large part of the space heating demand is caused by transmission losses through the building envelope. In compliance with the today's trend of designing sustainable and energy-saving architecture, it is necessary firstly to solve the factors influencing the energy balance. This year the subsidy for houses has been valued at € 8,000. The condition is that the building is classified in the energy class A0 according to the Energy Performance Act. Energy class A0 characterizes nearly zero energy buildings. The main concern is for the public to become interested in such buildings. The subsidy is designed to reward and promote those buildings that their heat and technical characteristics and modern technical equipment that meet energy class. In addition to a good plan to raise the profile of such buildings, there has been a lot of speculation to help make buildings in energy class A0. They are mainly owners of family houses where there is no gasification and are forced to have electricity as a source of heat and hot water. Electricity has a high primary energy factor, which means that buildings do not have to be approved.

scholarly journals An evaluation of the effects of thermal insulation levels on the energy performance of New Zealand office buildings- exploring the impact of building attributes on the performance of thermal insulation

2021 ◽  
Author(s):  
◽  
Brittany Grieve
Keyword(s):  
Energy Consumption ◽  
New Zealand ◽  
Thermal Insulation ◽  
Building Energy ◽  
Energy Performance ◽  
Building Envelope ◽  
Office Buildings ◽  
Building Performance ◽  
Energy Models ◽  
The Impact

<p>This thesis explored the impact of thermal insulation on the energy performance of New Zealand air-conditioned commercial office buildings. A sample of calibrated energy models constructed using real building performance data and construction information was used to ensure that the results produced were as realistic as possible to the actual building performance of New Zealand commercial office buildings. The aim was to assess how different climates and building attributes impact thermal insulation's ability to reduce energy consumption in New Zealand commercial office buildings.   Driven by the ever increasing demands for healthier, more comfortable, more sustainable buildings, building regulations have steadily increased the levels of insulation they require in new buildings over time. Improving the thermal properties of the building envelope with the addition of thermal insulation is normally used to reduce the amount of heating and cooling energy a building requires. Thermal insulation reduces the conductive heat transfer through the building envelope and with a higher level of thermal resistance, the less heat would transfer through the envelope. Consequently, the common expectation is that the addition of thermal insulation to the building envelope will always reduce energy consumption. However, this assumption is not always the case. For internal load dominated buildings located in certain climates, the presence of any or a higher level of thermal insulation may prevent heat loss through the wall, increasing the cooling energy required. This issue is thought to have not been directly examined in literature until 2008. However, an early study undertaken in New Zealand in 1996 found that for climates similar or warmer than Auckland, the addition of insulation could be detrimental to an office building's energy efficiency due to increased cooling energy requirements.  The energy performance of a sample of 13 real New Zealand office building energy models with varying levels of thermal insulation in 8 locations was examined under various scenarios. A parametric method of analysis using building energy modelling was used to assess the energy performance of the buildings. Buildings were modelled as built and standardised with the current NZS4243:2007 regulated and assumed internal load and operational values. The effect the cooling thermostat set point temperature had on the buildings' energy performance at varying levels of insulation was also tested.   The study concluded that the use of thermal insulation in New Zealand office buildings can cause an increase in cooling energy for certain types of buildings in any of the eight locations and thermal insulation levels explored in the study. The increase in cooling energy was significant enough to increase the total energy consumption of two buildings when modelled as built. These buildings were characterised by large internal loads, low performance windows with high window to wall ratios and low surface to volume ratios. The current minimum thermal resistance requirements were found to not be effective for a number of buildings in North Island locations.</p>

scholarly journals An evaluation of the effects of thermal insulation levels on the energy performance of New Zealand office buildings- exploring the impact of building attributes on the performance of thermal insulation

2021 ◽  
Author(s):  
◽  
Brittany Grieve
Keyword(s):  
Energy Consumption ◽  
New Zealand ◽  
Thermal Insulation ◽  
Building Energy ◽  
Energy Performance ◽  
Building Envelope ◽  
Office Buildings ◽  
Building Performance ◽  
Energy Models ◽  
The Impact

<p>This thesis explored the impact of thermal insulation on the energy performance of New Zealand air-conditioned commercial office buildings. A sample of calibrated energy models constructed using real building performance data and construction information was used to ensure that the results produced were as realistic as possible to the actual building performance of New Zealand commercial office buildings. The aim was to assess how different climates and building attributes impact thermal insulation's ability to reduce energy consumption in New Zealand commercial office buildings.   Driven by the ever increasing demands for healthier, more comfortable, more sustainable buildings, building regulations have steadily increased the levels of insulation they require in new buildings over time. Improving the thermal properties of the building envelope with the addition of thermal insulation is normally used to reduce the amount of heating and cooling energy a building requires. Thermal insulation reduces the conductive heat transfer through the building envelope and with a higher level of thermal resistance, the less heat would transfer through the envelope. Consequently, the common expectation is that the addition of thermal insulation to the building envelope will always reduce energy consumption. However, this assumption is not always the case. For internal load dominated buildings located in certain climates, the presence of any or a higher level of thermal insulation may prevent heat loss through the wall, increasing the cooling energy required. This issue is thought to have not been directly examined in literature until 2008. However, an early study undertaken in New Zealand in 1996 found that for climates similar or warmer than Auckland, the addition of insulation could be detrimental to an office building's energy efficiency due to increased cooling energy requirements.  The energy performance of a sample of 13 real New Zealand office building energy models with varying levels of thermal insulation in 8 locations was examined under various scenarios. A parametric method of analysis using building energy modelling was used to assess the energy performance of the buildings. Buildings were modelled as built and standardised with the current NZS4243:2007 regulated and assumed internal load and operational values. The effect the cooling thermostat set point temperature had on the buildings' energy performance at varying levels of insulation was also tested.   The study concluded that the use of thermal insulation in New Zealand office buildings can cause an increase in cooling energy for certain types of buildings in any of the eight locations and thermal insulation levels explored in the study. The increase in cooling energy was significant enough to increase the total energy consumption of two buildings when modelled as built. These buildings were characterised by large internal loads, low performance windows with high window to wall ratios and low surface to volume ratios. The current minimum thermal resistance requirements were found to not be effective for a number of buildings in North Island locations.</p>

Nearly Zero Energy Building (NZEB) using IoT and Smart Grid

2015 ◽  
Vol 3 (4) ◽  
pp. 340-342
Author(s):  
P. Deepak ◽  
Z. Anees Hussain
Keyword(s):  
Smart Grid ◽  
Energy Demand ◽  
Net Present Value ◽  
Ventilation System ◽  
Energy Performance ◽  
Building Envelope ◽  
Hot Water ◽  
Climate Mitigation ◽  
Large Set ◽  
Zero Energy

Current energy policy and climate mitigation goals require distinct reductions of the primary energy demand in the building sector. The existing building stock poses challenge since clear-cut technical and economical retrofit strategies for different types of existing buildings are still not established. The goal of the study is to identify such retrofit strategies to achieve optimal cost levels and to assess costs and benefits of nearly zero energy buildings (nZEB). Firstly building types are defined by covering single-family houses, multi-family houses, office buildings and school buildings. Secondly, a large set of generic energy efficiency measures are described, covering seven strategic fields, namely building envelope measures, heating and hot water supply technologies and fuel choice, ventilation and lighting systems, electricity and district heat mixes. This covers the usage of smart home appliances, eco-friendly building ventilation system. Thirdly, energy performance is calculated based on technical and physical characteristics and using building energy balance software. Fourthly, investment costs and life cycle costs are established based on unitary costs of building elements and building technologies. Cost-effectiveness is determined based on he net present value method which is compared to the annuity method for a couple of cases. The integration of smart grid and IoT(Internet of Things) is a new concept for conserving more.

scholarly journals Cost-efficient Nearly Zero-Energy Buildings

2019 ◽  
Vol 111 ◽  
pp. 03075 ◽  
Author(s):  
Heike Erhorn-Kluttig ◽  
Hans Erhorn ◽  
Micha Illner
Keyword(s):  
Life Cycle ◽  
Minimum Energy ◽  
Energy Performance ◽  
Building Envelope ◽  
Hot Water ◽  
Technical Solution ◽  
Zero Energy ◽  
Solution Sets ◽  
The Impact ◽  
New Buildings

The next level of energy performance of new buildings within the European Union will be the Nearly Zero-Energy Building (NZEB). A lot of work has been spent on pilot and demonstration buildings on this and also even higher energy performance levels throughout all EU countries. However, most of the high performance buildings realised so far result in higher investment costs when compared to the current national minimum energy performance requirements. The considerably higher investment costs are one of the main barriers to the early application of the NZEB-level in Europe. The EU H2020 project CoNZEBs works on technical solution sets that result in lower investment costs for NZEBs, bringing the costs close to those of conventional new buildings. The focus is on multi-family houses. In each of the four participating countries Germany, Denmark, Italy and Slovenia a team of researchers is analysing which sets of marketready technologies at the building envelope, the services systems for heating, domestic hot water, ventilation and cooling (where required) in combination with renewable energy systems can fulfil the NZEB requirements at lower costs than those incurred by the national mainstream NZEB application. Additional efforts are being spent on the life-cycle costs and the life-cycle analysis of the solution sets, as well as on the impact of future developments of primary energy factors, energy costs and technology efficiencies.

scholarly journals Case Study of Thermal Diagnostics of Single-Family House in Temperate Climate

Energies ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4549 ◽  
Author(s):  
Aleksandra Specjał ◽  
Aleksandra Lipczyńska ◽  
Maria Hurnik ◽  
Małgorzata Król ◽  
Agnieszka Palmowska ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Ventilation System ◽  
Energy Performance ◽  
Primary Energy ◽  
Building Envelope ◽  
Hot Water ◽  
Temperate Climate ◽  
Normative Values ◽  
Single Family ◽  
Family House

Reduction of the primary energy consumption is a crucial challenge for the building sector due to economic and environmental issues. Substantial savings could be achieved within the household. In this paper, we investigate the energy performance of a single-family house located in the temperate climate. The assessment is based on the comprehensive thermal diagnostic of the building performed on-site and via computational analyses. The on-site measurements included diagnostics of the building envelope, heat source, heating and domestic hot water system, ventilation system, and indoor environmental quality. Analyses confirmed that the studied building, which was built in 2008, meets the legislation requirements for the primary energy usage at that time and nowadays. However, results show discrepancies between energy performance obtained through on-site measurements and computational methods following regulations. Partially, discrepancies are a result of differences on normative values and how the building is operated in practice. It is also showed how important the role in the assessment of energy consumption through measurements is played by the measurement period.

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