Cost-optimal energy performance measures in a new daycare building in cold climate

Cool roof effectiveness in improving building thermal-energy performance is affected by different variables. In particular, roof insulation level and climate conditions are key parameters influencing cool roofs benefits and whole building energy performance. This work aims at assessing the role of cool roof in the optimum roof configuration, i.e., combination of solar reflectance capability and thermal insulation level, in terms of building energy performance in different climate conditions worldwide. To this aim, coupled dynamic thermal-energy simulation and optimization analysis is carried out. In detail, multi-dimensional optimization of combined building roof thermal insulation and solar reflectance is developed to minimize building annual energy consumption for heating–cooling. Results highlight how a high reflectance roof minimizes annual energy need for a small standard office building in the majority of considered climates. Moreover, building energy performance is more sensitive to roof solar reflectance than thermal insulation level, except for the coldest conditions. Therefore, for the selected building, the optimum roof typology presents high solar reflectance capability (0.8) and no/low insulation level (0.00–0.03 m), except for extremely hot or cold climate zones. Accordingly, this research shows how the classic approach of super-insulated buildings should be reframed for the office case toward truly environmentally friendly buildings.

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Energy Renovation versus Demolition and Construction of a New Building—A Comparative Analysis of a Swedish Multi-Family Building

Energies ◽

10.3390/en12112218 ◽

2019 ◽

Vol 12 (11) ◽

pp. 2218 ◽

Cited By ~ 5

Author(s):

Lina La Fleur ◽

Patrik Rohdin ◽

Bahram Moshfegh

Keyword(s):

Life Cycle ◽

Life Cycle Cost ◽

Energy Performance ◽

Optimal Energy ◽

Heated Floor ◽

New Construction ◽

Family Building ◽

1960S And 1970S ◽

Internal Volume ◽

The 1960S

This study addresses the life cycle costs (LCC) of energy renovation, and the demolition and construction of a new building. A comparison is made between LCC optimal energy renovations of four different building types with thermal performance, representing Swedish constructions from the 1940s, 1950s, 1960s, and 1970s, as well as the demolition of the building and construction of a new building that complies with the Swedish building code. A Swedish multi-family building from the 1960s is used as a reference building. LCC optimal energy renovations are identified with energy saving targets ranging between 10% and 70%, in addition to the lowest possible life cycle cost. The analyses show that an ambitious energy renovation is not cost-optimal in any of the studied buildings, if achieving the lowest LCC is the objective function. The cost of the demolition and construction of a new building is higher compared to energy renovation to the same energy performance. The higher rent in new buildings does not compensate for the higher cost of new construction. A more ambitious renovation is required in buildings that have a shape factor with a high internal volume to heated floor area ratio.

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An Approach to Improve Energy and Cost Performance of a Social Housing Archetype in Cold Climate Region

E3S Web of Conferences ◽

10.1051/e3sconf/201911103065 ◽

2019 ◽

Vol 111 ◽

pp. 03065

Author(s):

Yiğit Yılmaz ◽

Burcu Çiğdem Yılmaz

Keyword(s):

Life Cycle ◽

Physical Properties ◽

Social Housing ◽

Life Cycle Cost ◽

Energy Performance ◽

Cold Climate ◽

Temperate Climate ◽

Base Case ◽

Climate Region ◽

Thermo Physical Properties

The importance of building energy performance has been substantially increasing in the last decades due to the global warming. Therefore, buildings within the existing stock and the new buildings are encouraged to achieve the energy performance restrictions and efficiency levels. In this context, a social housing archetype (Harct), which is constructed in each climate region of Turkey with a common design approach for temperate climate region, is evaluated as a base case to improve the energy performance for the cold climate region by the optimization of the life cycle cost (LCC). It is, namely, aimed to not only improve the energy performance of the archetype but also to ensure optimal cost efficiency as significant criterion. It is focused to optimize the façades of the Harct in terms of window width, and optic and thermo-physical properties of the façade with determining the efficient insulation thickness level for exterior walls and efficient glazing types for windows. Firstly, façade design is analysed to find out the minimum and maximum windows’ widths to achieve the optimal window sizes. Secondly, optic and thermo-physical properties and cost data of the opaque and transparent façade elements have been designated among the market products in accordance with the current regulations. Energy model of the building has been run by Energy Plus simulation tool, in order to integrate it with GenOpt for optimization. Optimization was performed to carry out efficient frontier cases. The results were evaluated from life cycle cost (LCC) and energy efficiency point of view to highlight the cost optimal point

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