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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 minimize heat loss through foundations in a Passive House:
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Use of Insulated Foundations: Utilize a passive foundation that achieves a U-value of between 0.10 - 0.15 W/m²K. Ensure it's very well insulated to minimize heat loss.
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Preventing Thermal Bridging: Ensure no thermal bridges are present, as these significantly contribute to heat loss.
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Strong Materials: Implement high compressive strength materials for the foundation, such as autoclaved aerated concrete, which can also assist in thermal management.
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Blockwork to Retain Heat: Use blockwork that meets passive standards and incorporates thermal mass elements to help retain and redistribute heat.
Step 2
ground floor
Answer
In addressing the ground floor to maximize heat retention:
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Thermal Mass Utilization: Increase the thickness of the screed and tile finish. This increases the capacity of the floor to absorb and retain heat, providing a stable temperature.
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Airtightness: All ground floors should be designed to ensure airtightness, preventing unwanted air exchange that could lead to heat loss. Use materials that meet passive standards while ensuring the floor is insulated appropriately.
Step 3
Reasons why overheating occurs
Answer
Overheating in a Passive House can be attributed to several factors:
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Passive Solar Gain: During the summer months, passive solar gain can raise indoor temperatures, particularly if not adequately managed through design choices like shading.
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Poor Ventilation: If there is insufficient ventilation, it can lead to heat buildup inside the house, especially with the increase in appliance use, contributing to an overall warmer environment.
Step 4
Two design details to reduce the possibility of overheating
Answer
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Extended Roof Overhangs: Implementing extended roof overhangs can effectively reduce the amount of direct sunlight entering the house during summer, minimizing passive heat gain.
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Thermal Mass and Shading: Strategically include external shading devices and thermal mass features that absorb excess heat during peak sun hours and release it when temperatures cool down.
Step 5
Advantages and disadvantages of the Passive House standard
Answer
Advantages:
- Energy Efficiency: Passive Houses typically consume about 75% less energy compared to conventional homes due to their design, which leads to lower energy bills.
- Comfort: Consistent indoor temperatures are maintained with minimized drafts, providing high comfort levels for occupants.
Disadvantages:
- High Construction Costs: The materials and workmanship required to meet Passive House standards can lead to higher initial investment.
- Training and Credentials: Specialized training is needed for builders and designers to comply with the extensive standards, which may not always be readily available.