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Minimising heat loss and storing heat gain are important considerations in Passive House design - Leaving Cert Construction Studies - Question 10 - 2016
Question 10
Minimising heat loss and storing heat gain are important considerations in Passive House design. Using notes and freehand sketches, show best practice design detaili... show full transcript
Worked Solution & Example Answer:Minimising heat loss and storing heat gain are important considerations in Passive House design - Leaving Cert Construction Studies - Question 10 - 2016
Step 1
Foundations
Answer
To minimise heat loss in the foundations of a Passive House, a passive foundation system should achieve a U-value of between 0.10 - 0.15 W/m²K. Important considerations include:
- No thermal bridges should exist, which can allow for unwanted heat loss.
- The foundation should be well insulated to prevent heat loss, employing materials with high compressive strength, such as autoclaved aerated concrete or traditional strip foundations.
- Incorporating thermal mass can also aid in heat retention.
Step 2
Ground floor
Answer
For the ground floor, increasing the thickness of the screed and tile finish enhances the capacity to absorb and retain heat. Effective practices include:
- Ensuring a high level of insulation in the ground floor to prevent heat loss.
- Creating an airtight construction to mitigate air leakage.
- Using materials that meet passive standards and incorporate thermal mass, which will improve the overall energy efficiency.
Step 3
Reasons why overheating occurs in Passive House
Answer
Overheating in a Passive House typically occurs due to:
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Passive Solar Gain: Overheating arises when interior temperatures exceed a comfortable level, particularly when passive solar design does not account for summer conditions.
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Inadequate Thermal Mass: If the thermal mass is insufficient or not designed properly, it will not absorb and release the heat effectively, leading to discomfort during hot months.
Step 4
Two design features to reduce overheating
Answer
To mitigate overheating, consider the following design features:
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Extended Roof Overhangs: This feature reduces direct solar gain by providing shade during summer while allowing sunlight in during winter months.
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Dynamic Glazing Systems: These systems can adjust tint in response to environmental conditions, effectively managing solar heat gain and maintaining comfortable indoor temperatures.
Step 5
Advantages of making Passive House standard
Answer
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Low Energy Consumption: A typical Passive House uses about 75% less energy compared to similar buildings, significantly reducing energy bills and reliance on fossil fuels.
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Comfort Consistency: Passive House design provides consistent indoor temperatures, enhancing occupant comfort throughout the year.
Step 6
Disadvantages of making Passive House standard
Answer
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High Initial Cost: Construction materials and workmanship required for Passive Houses can be expensive, leading to higher upfront costs for builders and homeowners.
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Training Requirements: Significant training and expertise are necessary for designers and construction teams, which may result in limited availability of qualified professionals, thereby delaying projects.