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ESO Y4B · Technology
Sustainable technology · Sustainability and design

Bioclimatic architecture and energy saving

The cheapest and least polluting energy is the energy we do not need to use. Before installing a machine that burns electricity or fuel, bioclimatic architecture solves a good part of the problem with something that is free once the building has been built: its orientation, its materials and the way air circulates inside it.

Before you start, make sure you know: Energy and its consumption (3rd ESO)
Before you start, make sure you know: Percentages (2nd ESO)

Orientation and sun exposure

Animation of a south-facing facade with an overhang: the sun moves along its arc from the low winter position to the high summer one and back again. Its ray changes angle: in winter it enters beneath the overhang to the back of the home and in summer it is cut off by the overhang. house overhang winter sun summer sun S (south facade, receives low winter sun) N
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Explain what bioclimatic architecture is and name two of its characteristic strategies, stating what each one achieves.

Explain what bioclimatic architecture is and name two of its characteristic strategies, stating what each one achieves.

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In Spain, why is it beneficial to face the large windows of a house towards the south? Explain what this achieves in winter and what problem may arise in summer.

In Spain, why is it beneficial to face the large windows of a house towards the south? Explain what this achieves in winter and what problem may arise in summer.

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The figure shows the cross-section of a bioclimatic house, with a wall feature marked with ?. State what this feature is, what function it serves, and explain why the…

The figure shows the cross-section of a bioclimatic house, with a wall feature marked with ?. State what this feature is, what function it serves, and explain why the winter sun enters through the window while the summer sun does not.

? summer sun winter sun N S
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Thermal insulation, thermal bridges and glazing

Horizontal section of a brick facade with insulation: little heat escapes through the insulated wall, whereas much more escapes through the concrete pillar, which interrupts the insulation; it is a thermal bridge plan view (horizontal section) inside (warm) outside (cold) low U: little heat escapes concrete pillar high U at the pillar: much more escapes insulation brick brick thermal bridge
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Explain what the thermal insulation of a building is and name the two elements of a home where it is usually most important (roof, facades, windows), justifying your…

Explain what the thermal insulation of a building is and name the two elements of a home where it is usually most important (roof, facades, windows), justifying your choice.

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Explain why a double-glazed window insulates better than a single-glazed one: what role the air gap between the two panes of glass plays.

Explain why a double-glazed window insulates better than a single-glazed one: what role the air gap between the two panes of glass plays.

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Explain what thermal insulation in a building is and reason the meaning behind the phrase "insulation is the first form of heating", relating it to energy demand.

Explain what thermal insulation in a building is and reason the meaning behind the phrase "insulation is the first form of heating", relating it to energy demand.

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Thermal inertia and cross ventilation

Plan of a house with thick walls and two windows open on opposite facades: the fresh air enters on one side, spreads through the two rooms via the interior door and leaves through the opposite facade. fresh air passes through the whole house inlet higher pressure outlet lower pressure thick stone wall (thermal inertia) plan view · windows on opposite facades
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A classroom gets very hot in the afternoons during June. Propose three bioclimatic solutions (without air conditioning), order them from lowest to highest cost, and…

A classroom gets very hot in the afternoons during June. Propose three bioclimatic solutions (without air conditioning), order them from lowest to highest cost, and explain how each one works.

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Explain what cross ventilation is, how it is achieved in a home, and why it cools down a space without using electricity.

Explain what cross ventilation is, how it is achieved in a home, and why it cools down a space without using electricity.

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Explain what the "thermal mass" of thick walls is and how traditional houses in southern Spain take advantage of it to stay cool during the day and warm at night.

Explain what the "thermal mass" of thick walls is and how traditional houses in southern Spain take advantage of it to stay cool during the day and warm at night.

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Energy certification and labelling

Energy certification scale with seven horizontal bars from the letter A (lowest consumption, shortest bar) to G (highest consumption, longest bar) Energy performance certificate A B C D E F G less consumption more consumption
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What is the energy label on household appliances? Explain what its letter indicates and why it is worth looking at it (and at the annual consumption figure) before…

What is the energy label on household appliances? Explain what its letter indicates and why it is worth looking at it (and at the annual consumption figure) before buying.

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Design a school experiment to compare the insulating properties of three materials (cork, wool and polystyrene): setup with identical boxes and hot water or ice, which…

Design a school experiment to compare the insulating properties of three materials (cork, wool and polystyrene): setup with identical boxes and hot water or ice, which variable is measured, and how to ensure the test is fair.

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An office building in Madrid has its four facades completely glazed with conventional curtain walls. The owner company proposes installing identical tinted solar films…

An office building in Madrid has its four facades completely glazed with conventional curtain walls. The owner company proposes installing identical tinted solar films on all the building's glass to solve the heat problem in summer.\na) Refute why applying an identical solution on all four facades is a bioclimatic design mistake, analyzing solar radiation and thermal and lighting needs on the north facade compared to the south facade.\nb) Design a differentiated passive bioclimatic renovation proposal: indicate what type of solar shading (horizontal or vertical) you would install on the south facade and on the east and west facades considering solar altitude, and what thermal or glazing intervention you would prioritize on the north facade. Justify each decision.

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Real efficiency: the rebound effect and economic payback

Economic graph: the rising line of accumulated saving crosses the horizontal line of initial investment at the payback point, marked on the time axis. accumulated € time (years) initial investment accumulated saving payback point
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A $9\ \text{W}$ LED bulb replaces a $60\ \text{W}$ incandescent bulb that gave the same amount of light. If it is turned on for 4 hours a day, calculate how much energy,…

A $9\ \text{W}$ LED bulb replaces a $60\ \text{W}$ incandescent bulb that gave the same amount of light. If it is turned on for 4 hours a day, calculate how much energy, in $\text{kWh}$, is saved in a year (365 days).

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A home consumes $1.200\ \text{kWh}$ per year in electric heating (at $0,20\ \text{€/kWh}$). A company assures them: "If you invest $1.800\ \text{€}$ in insulating the…

A home consumes $1.200\ \text{kWh}$ per year in electric heating (at $0,20\ \text{€/kWh}$). A company assures them: "If you invest $1.800\ \text{€}$ in insulating the facade, you will reduce consumption by $40\ \%$ and pay off the work in about $5$ years, because energy prices keep rising."\na) Calculate the annual financial savings with the current rate and determine how many years it would actually take to pay off the investment without price increases.\nb) Refute the 5-year claim with data: what average price would the kWh need to be paid at during that period to pay off the $1.800\ \text{€}$ in just 5 years? Is it a realistic forecast?\nc) Technically justify whether you would recommend carrying out this work first or whether it would be advisable to prioritize low-cost measures (such as sealing window drafts or programmable thermostats), considering the cost-benefit ratio.

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A school replaces $100$ $60\ \text{W}$ fluorescent luminaires (which operated for $6\ \text{h/day}$) with $20\ \text{W}$ LED panels. An energy saving of $66,7\ \%$ was…

A school replaces $100$ $60\ \text{W}$ fluorescent luminaires (which operated for $6\ \text{h/day}$) with $20\ \text{W}$ LED panels. An energy saving of $66,7\ \%$ was projected. However, after the renovation, lighting electricity consumption was only reduced by $33,3\ \%$ because the staff, perceiving that "LEDs consume nothing", leave the lights on for an average of $12\ \text{h/day}$.\na) Calculate the original daily consumption in $\text{kWh}$, the projected consumption after installing the LEDs, and the resulting actual consumption. What percentage of the theoretical savings has been lost?\nb) Explain using these data what the "rebound effect" (or Jevons paradox) is and how it distorts energy efficiency forecasts.\nc) Design two automated technical measures (sensors, timers, or control systems) that prevent this rebound effect without relying on the will or behavior of the users.

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Summary

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