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.
Orientation and sun exposure
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.
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.
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.
Thermal insulation, thermal bridges and glazing
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.
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.
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.
Thermal inertia and cross ventilation
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.
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.
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.
Energy certification and labelling
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.
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.
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.
Real efficiency: the rebound effect and economic payback
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).
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.
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.