Defining an Innovative Design Method Based on the Life Cycle Approach

Abstract

This chapter will illustrate an experimental design model that can be used to produce two different outcomes based on two levels of assessments. This tool is called the Life Cycle Design Model (LCDM).

Appendices

Appendix 1: Simplified Calculation to Quantify the Thermal Dispersion of a Wall

The premise is to calculate the loss of thermal resistance of the technical element and, as a result, the increase in the amount of heat needed to warm the house in winter. Take, for example, a material—insulation inside a hollow wall—which at the end of its physical life cannot be replaced for functional and economic reasons.³⁹ The energy needed to maintain the initial conditions will have to be calculated for the life cycle period remaining to the building (70 years less the years during which the material performed its task).

The formula used in the model is based on the re-elaboration of the calculation method proposed by the Italian Agency for Energy and the Environment (ENEA) to quantify the annual savings of energy from primary sources thanks to an energy-efficient intervention.⁴⁰ The goal of this study is just the opposite. In other words, to determine the envisaged annual consumption in the case of loss of energy efficiency by the envelope. However the method is the same. Dispersion of the envelope element (ΔQ_a) can be identified by applying the formula:

$$ \Delta Q_{a} = \frac{{{\text{GG}} \times 24 \times {\text{f}} \times {\text{R}} \times \Delta {\text{U}} \times {\text{S}}}}{1000}[{\text{kWh}}] $$

where:

GG:

Daylight temperature (°C) at the site in question;

F:

Correction factor taking into consideration the average internal temperature (below 20 °C, since rooms are not heated throughout the day but only according to pre-established schedules).

For residential houses, the indication is f = 0.9, and in all other cases from 0.4 to 0.8.

R:

Correction factor of the difference in temperature according to the type of element;

suggested values:

R = 1 if the opaque element or window is between the heated room and the exterior;

R = 0.5 if the opaque element or window is between a heated room and an unheated room;

R = 0.8 if the opaque element or window is between a heated room and the ground or an unheated and ventilated room;

ΔU:

Variation in transmittance due to the loss of performance of the material (expressed in W/m² K)

S:

Surface area of an opaque element (S = 1 considering a surface of 1 m²).

The following equation can be used to calculate the amount of primary energy required for winter heating (ΔQ_pr)

$$ \Delta Q_{pr} = \frac{{\Delta Q_{a} }}{{\eta_{g} }}[{\text{kWh}}]\,\,{\text{with}}\,\,\eta_{g} = \eta_{p} \times \eta_{d} \times \eta_{r} \times \eta_{s} $$

where:

η_g:

Global average seasonal performance of the systems and the building.⁴¹

Defined as the ratio between the thermal energy requirement to provide winter heating and the primary energy of energy sources (including sources of electricity) calculated with reference to the annual operating period

η_p:

Production performance (UNI 10348)

η_d:

Distribution performance (UNI 10348)

η_r:

Regulation performance (UNI 10348)

η_e:

Emission performance (UNI 10348).

Appendix 2: Technical Sheet of the Envelope Elements

See Table 4.7

Table 4.7 Thermos-physics characteristics

Appendix 3: Life Cycle Environmental Analysis of the Envelope Elements

See Tables 4.8, 4.9 and 4.10.

Table 4.8 Process 1—construction stage—environmental analysis

Table 4.9 Process 2—use stage—environmental analysis

Table 4.10 Process 3—end of life stage—environmental analysis

Appendix 4: Life Cycle Cost Analysis of the Envelope Elements

See Tables 4.11, 4.12 and 4.13.

Table 4.11 Process 1—construction stage—cost analysis

Table 4.12 Process 2—use stage—cost analysis (Discount rate: 5%)

Table 4.13 Process 3—end of life stage—cost analysis (Discount rate: 5%)