1. Erasmus+ CBHE project 561890-2015E-JP
MARUEEB
Erasmus+ CBHE project E-JP
Influence of constructive solutions of buildings on their energy efficiency
Author: Strulev Sergey
Head: Evdokimtsev Oleg
St. Petersburg, 18nd September 2017
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2. Introduction
In modern society, the problem of reducing the consumption of primary energy is becoming ever more acute. Scientists around the world solve the problems associated with global energy efficiency. Construction, as one of the largest energy consumers on the planet, can't remain aloof from this problem.
The search for energy-efficient solutions in construction has been going on for a long time. However, the main attention is paid to the engineering equipment of building objects and the creation of impenetrable shells for them from the thermotechnical point of view. In the conditions of gradual exhaustion of opportunities to further increase energy efficiency in construction by traditional methods, this work aims to draw attention to the influence of the constructive decision of buildings on their energy consumption. It can be assumed that optimization of load-bearing structures of buildings will become a new driver for the development of energy efficiency of buildings and structures.

3. Influence of a constructive solution on the energy efficiency of buildings and structures
A rationally designed frame contributes to a reduction in the internal heated volume and, as a result, a reduction in the resources spent on maintaining the design temperatures in the room.
The optimization of the dimensions of the bearing core allows, with the preservation of the main parameters of the functional spaces, to reduce the area of the enclosing structures, which in turn leads to a reduction in heat losses.
Reducing the weight of structural elements and their number in the design, can reduce energy costs in production, delivery and installation.

4. Types of constructive solutions for enclosing structures in an energy efficient building
Double-skin facade

5. Hypothesis
Increasing the energy efficiency of buildings and structures by optimizing its design solution is a complex non-trivial task. Most often in the design of such facilities, special attention is paid to the insulation of the fence and the installation of modern engineering support for the building. At the same time, the efficiency of thermal insulation with thickness is reduced, and the expediency of using additional equipment is determined by the overall level of energy consumption of the facility. In the context of continuous tightening of environmental and energy requirements for construction projects, traditional ways to reduce heat losses are becoming less promising. In this case, it is necessary to look for new sources for improving the energy efficiency of buildings.
The solution of the problem can be the innovation of constructive solutions of the supporting framework of building objects. The idea may be to reduce the overall dimensions of the main structural elements of the frame, which leads, while maintaining the usable area and other characteristics that determine the functional filling of the room, to reduce the perimeter of the enclosing structures and the heated volume. As a result, it is possible to achieve a significant reduction in heat losses and costs for heating and air conditioning of the facility.

6. Possible ways of implementing the hypothesis
It is necessary to carry out a rational choice of structural material. The use of modern high-strength materials makes it possible to substantially reduce the cross-section dimensions of the bearing elements. High-strength concrete and steel, composite materials with high performance characteristics, as a rule, also have a high cost, which constrains their wide application in construction.
Reducing the overall dimensions of the basic structures of the frame can be by changing the principles of its work and the formation of a stress-strain state. In this case, a large amount of resources is required to conduct theoretical and practical research and implement the results.
The paradigm shift in the work of designers is necessary. The traditional approach involves the orientation of the cross-sections of the framework elements to minimize the mass of the final product. However, often a solution with a minimum finite mass of structures does not correspond to a variant with minimal overall dimensions, which, due to the lower bearing capacity of the elements, requires more of them, which leads to some weight gain. Orientation when designing for a different parameter of optimization of building systems will increase their energy efficiency.

7. Description of the case
«Innovations of constructive solutions of energy-efficient buildings (example)»
Description of the case
Planned construction of an industrial unheated building with the heated room located inside. Covering of heated object required to execute at the normal scheme of beam cells. Insulation of all surfaces are selected from the calculation to ensure sufficient thermal resistance and an equal amount of heat loss from all surfaces. The design of the cover has a height of unlimited technological parameters. It was therefore decided to use a story combination of elements of beam cells. You need to choose the design of girder cells, providing more energy efficiency of the facility at the lowest possible costs.
Available data
The designed facility is scheduled to be operated for 20 years. According to the results of thermal calculation we spend 10 kW/(m3∙0C) of thermal energy for heating the premises under consideration. The air temperature in winter in an unheated part of the building to 10 0C above the ambient air temperature. Construction is planned to be conducted in Nizhny Novgorod. In Nizhny Novgorod in 2016 the cost per kWh of thermal energy (Се) is 1.2 euro cents.

8. Available data Initial data for meaningful analysis beam cells
Year over year evolution of the heat cost
Year
Evolution Coefficient
2017
7,42%
2018
7,51%
2019
7,39%
2020
7,30%
2021
7,28%
2022
2023
7,29%
2024
7,31%
2025
2026
2027
2028
7,32%
2029
2030
2031
2032
2033
2034
7,27%
2035
7,26%
2036
7,25%
Parameter
Value
Units
Step of columns 6 m
Span between columns 12
Prescribed load 25
kN/m2
Number of cells 9
pcs
Design resistance of the steel
by the yield strength (Ry)
230
MPa
Design shear resistance of the steel (Rs)
140
Density of steel (ρ)
7850
kg/m3
Monthly distribution of average temperature for the city of Nizhny Novgorod
Month 1 2 3 4 5 6 7 8 9 10 11 12
Temp. (̊C)
-8,9
-8,8
-2,6
6,1
12,9
17,2
19,4
16,9
11,1
4,7
-2,8
-7,3

9. Formulation of the problem
The general scheme of the problem being solved

10. Mechanical analysis Thickness of deck (tn), mm12
Step of deck beams (ln), mm
1466,401792
Number of steps (n) 8,
Integer number of steps (n) 9
Step of deck beams (ln), m 1,
Bending moment of deck (M), kN·cm 1,
Acting stress of deck (σ), kN/cm2
11,
Operating deflection of deck (θ), sm 0,
Normative deflection of deck θu, sm 1,
Condition for strength: σ/Ry·γc≤1 for deck 0,
Сondition for stiffness: θ/θcr ≤1 for deck 0,
Weight of the deсk (ṁ), kg/m2
94,2
Bending moment of deck beam (Mmax), kN*cm
18593,46
Shear force of deck beam (Vmax), kN
123,9564
Required section modulus of deck beam (Wbn), cm3
734,
Section modulus of deck beam (Wbx),cm3
743
Normal stress of deck beam (σ)≤1 0,
Shear stress of deck beam (τ)≤1 0,
Deflection beam (θ) 2,
θ/θcr ≤1 for deck beam 0,
Weight of the deсk beam (ṁb), kg/m2
36,45

11. The difference between the traditional and energy-efficient approach

12. Energy and Economic Analysis
The comparison of total energy consumption for solutions with deck thickness of 3 mm,
5 mm and 12 mm
The comparison of versions of the beam cells layout

13. Key economic indicators of implementation of optimal solutions

14. Thank you very much for your attention!