Infrastructure Engineering - Research Publications
Permanent URI for this collection
Search Results
1 - 2 of 2
-
ItemAlternative Heating and Cooling Systems for the Retrofit of Medium-Rise Residential Buildings in Greece(WILEY-V C H VERLAG GMBH, 2021-11)The European Union recently set the target of doubling building retrofit rates through the European Green Deal. Currently, more than half of the households’ energy consumption is accounted for space conditioning, with southern European countries experiencing increasing demand for cooling systems over the past decade. Herein, the performance of market‐available heating and cooling systems that can replace the existing low‐efficiency systems in multiresidential buildings in Greece is compared. The study's objectives are to minimize the operating greenhouse gas emissions and the life‐cycle cost. Results demonstrate that air‐to‐air heat pumps have the lowest life‐cycle cost. In areas where natural gas is not available, the replacement of the diesel‐oil boiler with a biomass boiler leads to a 48% to 73% decrease of the operating greenhouse gas emissions. In areas where natural gas is available, the gas absorption heat pump has the lowest operating greenhouse gas emissions, demonstrating a reduction between 40% and 54% when compared to a conventional gas boiler; however, it dramatically increases the life‐cycle cost, making it less attractive than heat pumps and condensing gas boilers. The findings are in line with the current residential space conditioning market, while indicating the potential of biomass boilers and gas absorption heat pumps.
-
ItemLow energy building retrofit: A review of objectives and solutions(ZEMCH Network, 2018-01-29)Worldwide, the building sector is accountable for one-third of final energy consumption. This is expected to increase in the future. It is due to the continuing growth in demand for new buildings and the poor energy efficiency of the existing building stock. In developed countries, the ratio of new to old buildings is around 1% per year. According to the European Energy Performance of Buildings Directive Recast (Directive 2010/31/EU), optimal solutions towards low and near-Zero Energy Building (near ZEB) retrofit is of critical importance in order to achieve European Union (EU) climate and energy objectives. This has led to a large number of projects on deep building retrofit during the last 20 years. Each project has specific objective functions, depending on the adopted stakeholder’s perspective and the selected retrofit strategies are dictated by the objective functions set. This study investigates stakeholders (legislators, investors, owners and users), objectives and optimal retrofit strategies and their interrelationships. The focus is on residential buildings due to the significant opportunity for reducing their Greenhouse Gas (GHG) emissions. A matrix has been developed to classify information in order to facilitate comparison and apparent correlations to be identified. The expected outcome is the better understanding of stakeholders’ perspectives on financial, energy, GHG emissions, thermal comfort and the resulted optimal strategies.