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Fast fixes, re-think control policies. Work with nature!
Learn from the old building traditions - incorporate passive techniques and the building mass in the control policy and avoid peak demand crises.
The first obvious measure to reduce the energy use for heating of buildings is to improve the insulation and reduce the air leakage. Only simple steady state calculations are necessary to show this. Today this is reflected in most building codes prescribing U -values and air flow rates.
When those measures come to a certain limit, internal and solar heat gains will cover most of the heat losses and often even cause excess heat and overheating problems. Then there is nothing to gain by going on this way.
The common calculations and design principles are based on very rough simplifications and steady state conditions. Old knowledge, developed through hundreds years of experience, has during a few decades been replaced by principles that are based on constant temperature and that the energy needed always is proportional to the temperature difference outside - inside. (this factor of proportionality is commonly named the "U-value")
The reality in the current thinking can easily be exposed:
In an office of 10 sqm, built with todays building codes, the energy losses are around 10 W/K. During a working day the loads for lighting, machines and people can be 350-600 W and the sun through the window 700-1,000 W. In a calculation of steady state condition the rise of the temperature would be 135 degree Celsius. It would be very difficult for a person to survive longer than minutes. Common sense and experiences must tell us that this is not happening. But we are still dimensioning the HVAC system and controls for this case. It leads to a common over-dimensioning between 2-5 times of what is necessary and conflicting control policies that gives enormous waste.
Passive technology is the next step in saving energy in buildings. The thermal mass of the building structure is utilized to even out indoor temperature fluctuations and move excess energy from day to night, from one day to the next or from periods of warm weather to colder ones. This is what always has taken place in buildings before technology made it possible to maintain any desired constant indoor temperature by a prompt supply or extraction of energy (heating and cooling).
It is an old joke about military commands and command structure. "If the terrain and the map does not fit, follow the map". This joke fits even better on the common practices for design, dimensioning and control policies within the construction industry. The positive thing is the large gains that can be done, without replacing the constructions with new ones. It is a lot of possibilities for fast and efficient fixes. The fixes must be the first priority and far more important than expanding power production facilities. They will also better prepare us for use of renewable energy resources and avoid peak demand crises.
During the last decades building technology has been dominated by the stationary way of thinking, neglecting the storing - emitting process. One reason for this is the difficulties of handling the process mathematically. However, computers have now made it possible to solve these problems.
A very modern tool has thus helped us to recover old, lost experiences and make advantages to be gained from the building traditions clearly discernible, which leads to the basic philosophy to work with nature instead of against it. The building thermal capacity can be utilized to reduce the energy use to a level far beyond what a steady state calculation indicates.
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BIOFUELS ASIA
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2008 - 27th-28th March 2008,
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Energy Savings in
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Energy Savings in
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"Disturbed children"
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